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Introduction: We aimed to identify the role of radiotherapy (RT) in the treatment of thymic carcinoma as well as the optimal RT target volume. Materials and Methods: This single-institution retrospective study included 116 patients diagnosed with thymic carcinoma between November 2006 and December 2021 who received multimodal treatment including RT with or without surgery or chemotherapy. Seventy-nine patients (68.1%) were treated with postoperative RT, 17 patients (14.7%) with preoperative RT, 11 patients (9.5%) with definitive RT, and nine patients (7.8%) with palliative RT. The target volume was defined as the tumor bed or gross tumor with margin, and selective irradiation of the regional nodal area was performed when involved. Results: With a median follow-up of 37.0 (range, 6.7–174.3) months, the 5-year overall survival (OS), progression-free survival, and local recurrence-free survival rates were 75.2%, 47.7% and 94.7%, respectively. The 5-year OS was 51.9% in patients with unresectable disease. Overall, 53 recurrences were observed, of which distant metastasis was the most common pattern of failure (n = 32, 60.4%) after RT. No isolated infield or marginal failures were observed. Thirty patients (25.8%) who had lymph node metastases at the initial diagnosis had regional nodal areas irradiated. There was no lymph node failure inside the RT field. A tumor dimension of ≥5.7 cm (hazard ratio [HR] 3.01; 95% confidence interval [CI] 1.25–7.26; p = 0.030) and postoperative RT (HR 0.20; 95% CI 0.08–0.52; p = 0.001) were independently associated with OS. Intensity-modulated-RT-treated patients developed less overall toxicity (p < 0.001) and esophagitis (p < 0.021) than three-dimensional-conformal-RT-treated patients. Conclusions: A high local control rate was achieved with RT in the primary tumor sites and involved lymph node area in the treatment of thymic carcinoma. A target volume confined to the tumor bed or gross tumor plus margin with the involved lymph node stations seems reasonable. The advanced RT techniques with intensity-modulated RT have led to reduced RT-related toxicity.

Metabolic parameters evaluated by 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) are known as prognostic markers in various cancers. We aimed to validate the predictive value of mid-radiotherapy (RT) FDG PET/CT parameters in esophageal cancer.Eighty-three patients treated with RT with or without chemotherapy between 2015 and 2020 were included. PET parameters including metabolic tumor volume (MTV), total lesion glycolysis, and mean (SUVThe median follow-up period was 10.5 months. Mid-RT SUVTumor metabolism changes during RT can be a useful predictive tool for treatment response and recurrence in patients with esophageal cancer. Clinicians may consider early response evaluation with PET during RT for predicting prognosis information about prognosis.

We investigated dental implant outcomes in patients who had previously received radiotherapy (RT) for head and neck malignancies.We reviewed 90 dental implants in 27 patients who received RT for head and neck cancer and received dental implants afterwards. The cumulative implant survival rate (CISR) was calculated. In addition, the implant quality was assessed using "Health Scale for Dental Implants."The CISR at 3 years was 79.6%. The mean radiation dose at the implant site (DD

Purpose: Pulmonary large cell neuroendocrine carcinoma (LCNEC) is a high-grade lung neuroendocrine tumor with a poor prognosis, similar to small cell lung cancer (SCLC). However, it remains unclear whether to treat LCNEC as non-small-cell lung cancer (NSCLC) or as SCLC. We reviewed our experiences to suggest appropriate treatment strategy for resected pulmonary LCNEC.Materials and Methods: Forty-four patients were treated for pathologically diagnosed pulmonary LCNEC during 2005‒2018. We considered curative surgery first in early-stage or some locally advanced tumors, unless medically inoperable. Adjuvant treatments were decided considering patient’s clinical and pathological features. After excluding two stage I tumors with radiotherapy alone and three stage III tumors with upfront chemotherapy, we analyzed 39 patients with stage I‒III pulmonary LCNEC, who underwent curative resection first. Results: Adjuvant chemotherapy (NSCLC-based 91%, SCLC-based 9%) was performed in 62%, and adjuvant radiotherapy was done in three patients for pN2 or positive margin. None received prophylactic cranial irradiation (PCI). With a median follow-up of 30 months, the 2- and 5-year overall survival (OS) rates were 68% and 51%, and the 2- and 5-year recurrence-free survival (RFS) rates were 49% and 43%, respectively. Aged ≥67 years and SCLC-mixed pathology were significant poor prognostic factors for OS or RFS (p < 0.05). Among 17 recurrences, regional failures were most common (n = 6), and there were five brain metastases. Conclusions: Surgery and adjuvant treatment (without PCI) could achieve favorable outcomes in pulmonary LCNEC, which was more similar to NSCLC, although some factors worsened the prognosis. The importance of intensified adjuvant therapies with multidisciplinary approach remains high.

The present study aimed to identify the mechanisms underlying the increase in vascular permeability in mouse skin following irradiation. The left ears of C3H mice were subjected to 2 and 15 Gy of radiation in a single exposure. At 24 h after irradiation, the ears were excised and tissue sections were stained with toluidine blue to assess mast cell degranulation. Vascular endothelial growth factor (VEGF) expression was assessed via immunohistochemistry and western blotting. Approximately 5% (3%–14%) (mean [95% CI]) of mast cells in the skin of control mice were degranulated; moreover, at 24 h after 2 Gy irradiation, this value increased to approximately 20% (17%–28%). Mast cell degranulation by 15 Gy irradiation (32% [24%–40%]) was greater than that by 2 Gy irradiation. Significant differences were observed in mast cell degranulation among the control, 2 Gy and 15 Gy groups (p = 0.012). Furthermore, VEGF-positive reactions were observed in the cytoplasm of scattered fibroblasts in the dermis. In immunohistochemistry tests, VEGF expression at 24 h after irradiation increased slightly in the 2 Gy group compared to that in the control group, whereas no difference in VEGF expression was observed in the 15 Gy group compared to that in the control group. Expression of VEGF in western blots was consistent with that in immunohistochemistry. In conclusion, mast cell degranulation was increased in mouse skin at 24 h after irradiation in a dose-dependent manner. In contrast, VEGF expression was slightly increased following only low-dose (2 Gy) irradiation.

PURPOSE: We investigated the dynamics of lymphocyte depletion and recovery during and after definitive concurrent chemoradiotherapy (CCRT), dose to which structures is correlated to them, and how they affect the prognosis of stage III non-small cell lung cancer (NSCLC) patients undergoing maintenance immunotherapy. METHODS AND MATERIALS: In this retrospective study, absolute lymphocyte counts (ALC) of 66 patients were obtained before, during, and after CCRT. Persistent lymphopenia was defined as ALC

Chondroradionecrosis (CRN) is an infrequent phenomenon after definitive RT. The clinical manifestation is usually difficult to distinguish from that of tumor recurrence; however, clinicians should be aware of the possibility of CRN.

BACKGROUND Generally, radiotherapy for patients with early glottic cancer includes treatment of the whole larynx. This study was conducted to evaluate the treatment outcomes and toxicity in patients who received single vocal cord irradiation (SVCI) for T1a classification glottic cancer. METHODS A total of 34 patients diagnosed with clinical T1aN0M0 classification squamous cell carcinoma of the glottis who received radiotherapy to the single vocal cord were included for analysis. RESULTS Median follow-up period was 41.3 months (range, 6.4-124.5 months). The 3-year and 5-year local control (LC) rates were both 96.8%. Grade 3 radiation dermatitis was observed as severe acute toxicity in two (6%) patients. No patients experienced any severe late toxicity events during follow-up. CONCLUSIONS SVCI showed good LC, low acute and late toxicities, and reasonable voice recovery. SVCI may be considered a feasible treatment strategy for patients with T1a glottic cancer.

The interest in combining radiation therapy (RT) with immunotherapy is increasing. We investigated the significance of lymphopenia in patients receiving immunotherapy for non-small cell lung cancer (NSCLC), and the factors associated with treatment-related lymphopenia, with particular emphasis on RT.In this retrospective single institution study, 268 patients with advanced NSCLC received immunotherapy, of whom 146 received RT. Lymphopenia was defined as an absolute lymphocyte count1000 cells/mm.At median 6.4 months of follow-up, patients with peri-immunotherapy lymphopenia (n = 146; 54.5%) showed significantly poorer progression-free survival (PFS) (median PFS: 2.2 vs 5.9 months, P.001) and overall survival (OS) (median OS: 5.7 vs 12.1 months, P.001). On multivariate analysis, peri-immunotherapy lymphopenia remained a significant prognostic factor for both PFS and OS. RT significantly increased peri-immunotherapy lymphopenia with an odds ratio (OR) of 1.91 (P = .025). Factors associated with the development of RT-associated lymphopenia included multiple courses (OR, 3.78; P.001), multiple irradiated sites (OR, 4.77; P = .018), and higher dose (≥50 Gy) (OR, 3.75; P = .004). Conversely, stereotactic body RT/radiosurgery reduced the risk (OR 0.21; P = .002).Lymphopenia was indicative of poor prognosis in NSCLC patients receiving immunotherapy and was significantly associated with more intensive RT. Choosing appropriate RT regimens and techniques may be essential in reducing lymphopenia. Promising results are expected in the era of precision RT.

Background/Aims: Endoscopic resection is a standard treatment for stage T1a esophageal cancer, with esophagectomy or radical radiation therapy (RT) performed for stage T1b lesions. This study aimed to compare treatment outcomes of each modality for clinical stage T1 esophageal cancer. Methods: In total, 179 patients with clinical T1N0M0- stage esophageal cancer treated from 2006 to 2016 were retrospectively evaluated. Sixty-two patients with clinical T1a-stage cancer underwent endoscopic resection. Among 117 patients with clinical T1b-stage cancer, 82 underwent esoph-agectomy, and 35 received chemoradiotherapy or RT. We compared overall survival (OS) and recurrence-free survival (RFS) rates for each treatment modality. Results: The median follow-up time was 32 months (range, 1 to 120 months). The 5-year OS and RFS rates for patients with stage T1a cancer receiving endoscopic resection were 100% and 85%, respectively. For patients with stage T1b, the 5-year OS and RFS rates were 78% and 77%, respectively, for the esophagectomy group; 80% and 44%, respectively, for the RT alone group; and 96% and 80%, respectively, for the chemoradiation group. The esophagectomy group showed significantly higher RFS than the RT alone group (p=0.04). There was no significant difference in RFS between the esophagectomy and chemoradiation groups (p=0.922). Grade 4 or higher treatment-related complications occurred in four patients who underwent esophagectomy. Conclusions: Endoscopic resection appeared to be an adequate treatment for patients with T1a-stage esophageal cancer. The multidisciplinary approach involving chemoradiation was comparable to esophagectomy in terms of survival outcome without serious complications for T1b-stage esophageal cancer. (Gut Liver 2019;13:315-324)

Background To identify whether early metabolic responses as determined using 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) during radiotherapy (RT) predict outcomes in patients with esophageal cancer. Methods Twenty-one patients with esophageal cancer who received pre-treatment 18F-FDG PET/CT (PET1) and inter-fractional 18F-FDG PET/CT (PET2) after 11 fractions of RT (median 23.1 Gy, 2.1 Gy per fraction) were retrospectively reviewed. The region of interest for each calculation was delineated using “PET Edge”. We calculated PET parameters including maximum and mean standardized uptake values (SUVmax and SUVmean, respectively), metabolic tumor volume (MTV), and total lesion glycolysis (TLG). The relative changes (%) were calculated using the logarithmically transformed parameter values for the PET1 and PET2 scans. Multivariate analysis of locoregional recurrence and distant failures were performed using Cox regression analysis. After identifying statistically significant PET parameters for discriminating responders from non-responders, receiver operating characteristics curve analyses were used to assess the potentials of the studied PET parameters. Results After a median follow-up of 13 months, the 1-year overall and progression-free survival rates were 79.0% and 34.4%, respectively. Four patients developed locoregional recurrences (LRRs) and 8 had distant metastases (DMs). The 1-year overall LRR-free rate was 76.9% while the DM-free rate was 60.6%. The relative changes in MTV (ΔMTV) were significantly associated with LRR (p = 0.03). Conversely, the relative changes in SUVmean (ΔSUVmean) were associated with the risk of DM (p = 0.02). An ΔMTV threshold of 1.14 yielded a sensitivity of 60%, specificity of 94%, and an accuracy of 86% for predicting an LRR. Additionally, a ΔSUVmean threshold of a 35% decrease yielded a sensitivity of 67%, specificity of 83%, and accuracy of 76% for the prediction DM. Trial registration Retrospectively registered. Conclusions Changes in tumor metabolism during RT could be used to predict treatment responses, recurrences, and prognoses in patients with esophageal cancer.

Numerical simulations of the bubble-bursting phenomenon in two tandem bubbles at the free surface are conducted to explore the influence of a following bubble behind the bursting bubble on the jet ejection at fixed Bo = 0.05 and Oh = 0.022. The equivalent radius of the bursting bubble ( RB) is fixed, and the configuration of two tandem bubbles is varied systematically by changing the equivalent radius of the following bubble ( RF) and the gap distance between the two bubbles ( L). An increase in the bubble–bubble interactive force (repulsive force) is observed with a decrease in L or an increase in RF. As the repulsive force increases, the velocity of the primary capillary wave (PCW) increases due to the reduced wavelength of the PCW, thus increasing the bursting jet velocity. However, when the repulsive force is sufficiently large, the curvature of the PCW near the bottom of the bursting bubble is reversed, causing a new secondary capillary wave to be generated. An increase in the secondary capillary wavelength with an increase in the force disturbs the self-similar behavior of the interface of the bursting bubble, resulting in a decrease in the bursting jet velocity. In order to scale the bursting jet velocity using RF and L in cases where PCWs are important to induce a bursting jet, a scaling law is formulated by defining the scaling variable φ in terms of RF and L. The proposed scaling law is found to be capable of providing accurate predictions of capillary numbers as a function of φ.

We evaluated intracranial failure after hippocampus-avoidance-prophylactic cranial irradiation (HA-PCI) for limited-stage small-cell lung cancer (SCLC). Data of 106 patients who received PCI with 25 Gy were retrospectively reviewed. The patients were divided into two groups based on whether they underwent HA-PCI: the HA-PCI group (n = 48) and the conventional PCI (C-PCI) group (n = 58). Twenty-one patients experienced intracranial failure: 11 and 10 patients in the C-PCI and HA-PCI groups, respectively. Using the log-rank test, the intracranial failure rate was not significantly different between the groups (p = 0.215). No clinical factor was significantly associated with intracranial failure in multivariate Cox regression analysis, but HA-PCI tended to be associated with increased incidence of intracranial failure (HR 2.87, 95% CI 0.86–9.58, p = 0.087). Among patients who received HA-PCI, two developed peri-hippocampal recurrence. A higher thoracic radiotherapy dose (≥ 60 Gy) was significantly associated with DFS (HR 0.52, p = 0.048) and OS (HR 0.35, p = 0.003). However, HA-PCI was associated with neither DFS nor OS. Although HA-PCI may be associated with an increased risk of intracranial failure, HA-PCI did not impair disease control or survival. Future prospective randomized trials are needed to reach a definite conclusion.

The study aimed to investigate the clinical significance of interim response evaluation during definitive chemoradiotherapy (dCRT) in predicting overall treatment response and survival of patients with locally advanced esophageal squamous cell carcinoma (LAESCC). We reviewed 194 consecutive patients treated with dCRT for biopsy-confirmed LAESCC. A total of 51 patients met the inclusion criteria. Interim response was assessed by defining a region of interest in initial and adaptive computed tomography (CT) images and subsequently examined against the overall treatment response assessed three months after dCRT, treatment failure pattern, overall survival (OS), and progression-free survival (PFS) estimates. Reductions in both the area and maximal diameter of the primary lesion (p &lt, 0.001, p &lt, 0.001, respectively) and those of the metastatic lymph nodes (LN) (p = 0.002, 0.001, respectively) in interim analysis were significantly higher among patients who achieved complete response (CR) than among those who did not. OS was significantly longer among patients who showed ≥30% interim reduction in the area and maximal diameter of the primary lesion and among those who showed such reduction in both the primary lesion and LN. PFS was significantly longer in the patients with ≥30% interim reduction in the area of the primary lesion. In addition, the proportion of cases with locoregional failure began decreasing at interim response of 20% or higher, while the proportion of cases with outfield failure followed the opposite pattern, increasing at interim response of 20% or higher. Among patients treated with dCRT for LAESCC, interim response assessed using adaptive CT images correlated with overall CR and OS rates. The evaluation of tumor burden reduction during dCRT may help predict patient prognosis.

This study investigated the feasibility of deep learning-based segmentation (DLS) and continual training for adaptive radiotherapy (RT) of head and neck (H&amp, N) cancer. One-hundred patients treated with definitive RT were included. Based on 23 organs-at-risk (OARs) manually segmented in initial planning computed tomography (CT), modified FC-DenseNet was trained for DLS: (i) using data obtained from 60 patients, with 20 matched patients in the test set (DLSm), (ii) using data obtained from 60 identical patients with 20 unmatched patients in the test set (DLSu). Manually contoured OARs in adaptive planning CT for independent 20 patients were provided as test sets. Deformable image registration (DIR) was also performed. All 23 OARs were compared using quantitative measurements, and nine OARs were also evaluated via subjective assessment from 26 observers using the Turing test. DLSm achieved better performance than both DLSu and DIR (mean Dice similarity coefficient, 0.83 vs. 0.80 vs. 0.70), mainly for glandular structures, whose volume significantly reduced during RT. Based on subjective measurements, DLS is often perceived as a human (49.2%). Furthermore, DLSm is preferred over DLSu (67.2%) and DIR (96.7%), with a similar rate of required revision to that of manual segmentation (28.0% vs. 29.7%). In conclusion, DLS was effective and preferred over DIR. Additionally, continual DLS training is required for an effective optimization and robustness in personalized adaptive RT.

Purpose The benefits of reirradiation for head and neck cancer (HNC) have not been determined. This study evaluated the efficacy of reirradiation using intensity-modulated radiotherapy (IMRT) for recurrent or second primary HNC (RSPHNC) and identified subgroups for whom reirradiation for RSPHNC is beneficial. Materials and methods A total of 118 patients from seven Korean institutions with RSPHNC who underwent IMRT-based reirradiation between 2006 and 2015 were evaluated through retrospective review of medical records. We assessed overall survival (OS) and local control (LC) within the radiotherapy (RT) field following IMRT-based reirradiation. Additionally, the OS curve according to the recursive partitioning analysis (RPA) suggested by the Multi-Institution Reirradiation (MIRI) Collaborative was determined. Results At a median follow-up period of 18.5 months, OS at 2 years was 43.1%. In multivariate analysis, primary subsite, recurrent tumor size, interval between RT courses, and salvage surgery were associated with OS. With regard to the MIRI RPA model, the class I subgroup had a significantly higher OS than class II or III subgroups. LC at 2 years was 53.5%. Multivariate analyses revealed that both intervals between RT courses and salvage surgery were prognostic factors affecting LC. Grade 3 or more toxicity and grade 5 toxicity rates were 8.5% and 0.8%, respectively. Conclusion IMRT-based reirradiation was an effective therapeutic option for patients with RSPHNC, especially those with resectable tumors and a long interval between RT courses. Further, our patients' population validated the MIRI RPA classification by showing the difference of OS according to MIRI RPA class.

Purpose The indication of elective neck treatment (ENT) for clinically N0 (cN0) paranasal sinus (PNS) carcinoma remains unclear. We aimed to investigate different treatment outcomes regarding ENT and propose optimal recommendations for ENT. Materials and methods We identified patients with cN0 PNS carcinoma who underwent curative-intent treatment between 1992 and 2015. Survival outcomes and pattern of failure were compared between patients who received ENT and those who did not. We sought to identify significant patient or pathologic factors regarding treatment outcomes. Results Among 124 patients meeting the inclusion criteria, 40 (32%) received ENT ('ENT (+) group') and 84 (68%) did not ('ENT (-) group'). With a median follow-up of 54 months, the 5-year overall survival (OS) was 67%, and the 5-year progression-free survival (PFS) was 45%. There was no significant difference between the ENT (+) and ENT (-) groups regarding OS (p = 0.67) and PFS (p = 0.50). Neither group showed a significantly different pattern of failure, including regional failure (p = 0.91). There was no specific benefit, even in the subgroups analysis by tumor site, histologic type, and T stage. Nevertheless, patients who ever had regional and/ or distant failure showed significantly worse prognosis. Conclusion ENT did not significantly affect the survival outcome or pattern of failure in patients with cN0 PNS carcinomas, showing that ENT should not be generalized in this group. However, further discussion on the optimal strategy for ENT should continue because of the non-negligible regional failure rates and significantly worse prognosis after regional failure events.

Purpose The purpose of this study was to compare the clinical and functional outcomes in patients with primary base of tongue (BOT) cancer who received definitive radiotherapy (RT) or surgery followed by radiotherapy (SRT). Materials and Methods Between January 2002 and December 2016, 102 patients with stage I-IVB primary BOT cancer underwent either definitive RT (n=46) or SRT (n=56), and treatment outcomes were compared between two groups. The expression of p16 was also analyzed. Results The RT group had more patients with advanced T stage (T3-4) disease (58.7% vs. 35.7%, p=0.021) and who received chemotherapy (91.3% vs. 37.5%, p < 0.001) than the SRT group. At a median follow up of 36.9 months (range, 3.3 to 181.5 months), the 5-year overall survival (OS) and disease-free survival (DFS) were 75.5% and 68.7%, respectively. With respect to treatment group, the 5-year OS and DFS in the RT and SRT groups did not differ significantly (OS, 68.7% vs. 80.5%, p=0.601; DFS, 63.1% vs. 73.1%, p=0.653). In multivariate analysis, OS differed significantly according to p16 expression (p16-negative vs. p16-positive; hazard ratio [HR], 0.145; 95% confidence interval [CI], 0.025 to 0.853; p=0.033). Regarding DFS, p16 expression (p16-negative vs. p16-positive; HR, 0.164; 95% CI, 0.045 to 0.598; p=0.006) showed a significant effect in multivariate analysis. Functional defects (late grade ≥ 3 dysphagia or voice alteration) were more frequently reported in the SRT than in the RT group (16.1% vs. 2.2%, p=0.021). Conclusion Despite advanced disease, patients in the RT group showed comparable survival outcomes and better functional preservation than those in the SRT group.

Purpose The purpose of this study was to compare the treatment outcomes of definitive radiotherapy (RT) with cordectomy in patients with early glottic cancer. Materials and methods A total of 165 patients who were diagnosedwith T1/2 squamous cell carcinoma of the glottic larynx between January 2006 and December 2012 were retrospectively analyzed. A total of 112 patients received RT and 53 patients received cordectomy. Local control (LC), disease-free survival (DFS), overall survival (OS), and larynx preservation rates after RT and cordectomy were investigated. Results The median follow-up period was 77.7 months (range, 10.7 to 127.0 months). The 3- and 5-year LC rates were 91.9% and 89.9%, respectively, for the RT group, and 82.8% and 73.2%, respectively, for the cordectomy group (p=0.006). The 3- and 5-year DFS rates were 87.5% and 83.7%, respectively, for the RT group and 79.2% and 68.0%, respectively, for the cordectomy group (p=0.046). No significant differences were identified in the 5-year OS (92.8% vs. 90.6%, p=0.713) or larynx preservation rates (98.2% vs. 97.2%, p=0.831) between groups. The major failure pattern was local failure (n=26), followed by regional (n=3) and distant failure (n=2). Multivariate analysis of LC showed that T2 stage (p=0.012) and receiving cordectomy as initial treatment (p=0.001) were significantly associated with poorer LC. Conclusion RT resulted in higher rates of LC and DFS compared to cordectomy for early glottic cancer. Treatment with radiotherapy is feasible and should be encouraged for both T1 and T2 glottic cancer.

Purpose The impact of postoperative ipsilateral neck radiotherapy (INRT) versus bilateral neck radiotherapy (BNRT) on the clinical outcomes of patients with tonsillar squamous cell carcinoma was analyzed retrospectively. Materials and Methods Between October 2001 and June 2012, 241 patients with T1-2 and N0-N2b tonsillar carcinoma from 16 institutes underwent postoperative INRT (n=84) or BNRT (n=157) following a tonsillectomy. Seventy patients were identified from each group by propensity score matching and compared in terms of the overall survival (OS), disease-free survival (DFS), locoregional relapse-free survival (LRRFS), and distant metastasis-free survival (DMFS) rates calculated using the Kaplan-Meier method with a log-rank test. Results The median follow-up was 55 months (range, 3 to 133 months). The survival outcomes in the INRT and BNRT groups were similar: 5-year OS (92.8% vs. 94.0%, p=0.985), DFS (80.5% vs. 94.2%. p=0.085), LRRFS (88.1% vs. 97.1%, p=0.083), and DMFS (92.7% vs. 97.0%, p=0.370). Subgroup analysis revealed no contralateral neck recurrence in 61 patients with T1-2N0-2a regardless of the treatment groups. For 79 patients with N2b, contralateral neck recurrence was more common in the INRT group than in the BNRT group (7.9% vs. 0.0%), but the difference was not significant (p=0.107). The overall grade ≥ 2 toxicities were lower in the INRT group: acute (45.7% vs. 74.3%, p=0.001) and late (4.3% vs. 31.4%, p < 0.001), respectively. Conclusion INRT is an attractive strategy for patients with T1-2N0-2a tonsillar carcinoma compared to BNRT. For patients with N2b, there was a small risk of contralateral neck recurrence when treated with INRT, but its impact on the OS was limited with successful salvage treatment.

Purpose The correlation between radiation dose and loco-regional control (LRC) was evaluated in patients with stage II-III esophageal cancer treated with definitive concurrent chemoradiotherapy (CRT). Materials and Methods Medical records of 236 stage II-III esophageal cancer patients treated with definitive CRT at Yonsei Cancer Center between 1994 and 2013 were retrospectively reviewed. Among these, 120 received a radiation dose of < 60 Gy (standard-dose group), while 116 received ≥ 60 Gy (high-dose group). The median doses of radiation in the standard- and high-dose groups were 50.4 and 63 Gy, respectively. Concurrent 5-fluorouracil/cisplatin chemotherapy was administered to most patients. Results There were no differences in patient characteristics between the two groups except for high Karnofsky performance status and lower-thoracic lesions being more prevalent in the standard-dose group. The median progression-free survival (PFS) and overall survival (OS) times were 13.2 months and 26.2 months, respectively. Patients in the high-dose group had significantly better 2-year LRC (69.1% vs. 50.3%, p=0.002), median PFS (16.7 months vs. 11.7 months, p=0.029), and median OS (35.1 months vs. 22.3 months, p=0.043). Additionally, LRC exhibited a dose-response relationship and the complete response rate was significantly higher in the high-dose group (p=0.006). There were no significant differences in treatment-related toxicities between the groups. Conclusion A higher radiation dose (> 60 Gy) is associated with increased LRC, PFS, and OS in patients with stage II-III esophageal cancer treated with definitive CRT.

Purpose To evaluate intracranial control after surgical resection according to the adjuvant treatment received in order to assess the optimal radiotherapy (RT) dose and volume. Materials and Methods Between 2003 and 2015, a total of 53 patients with brain oligometastases from non-small cell lung cancer (NSCLC) underwent metastasectomy. The patients were divided into three groups according to the adjuvant treatment received: whole brain radiotherapy (WBRT) ± boost (WBRT ± boost group, n = 26), local RT/Gamma Knife surgery (local RT group, n = 14), and the observation group (n = 13). The most commonly used dose schedule was WBRT (25 Gy in 10 fractions, equivalent dose in 2 Gy fractions [EQD2] 26.04 Gy) with tumor bed boost (15 Gy in 5 fractions, EQD2 16.25 Gy). Results The WBRT ± boost group showed the lowest 1-year intracranial recurrence rate of 30.4%, followed by the local RT and observation groups, at 66.7%, and 76.9%, respectively (p = 0.006). In the WBRT ± boost group, there was no significant increase in the 1-year new site recurrence rate of patients receiving a lower dose of WBRT (EQD2)

Background and purpose Based on the 6th edition of the American Joint Commission on Cancer (AJCC) staging system for esophageal squamous cell carcinoma (ESCC), M1a node involvement was classified as regional node involvement in the revised 7th/8th edition. However, the clinical significance of M1a node involvement is unclear. Thus, we analyzed the prognostic value of M1a node involvement in patients with ESCC after definitive concurrent chemoradiotherapy (CCRT). Materials and methods In total, 188 patients with ESCC had M0 disease according to the 7th/8th edition AJCC. We reclassified 31 (16.5%) of these patients as having M1a disease according to the 6th edition. After definitive CCRT, we compared baseline characteristics between the two groups and analyzed the rates of responders and recurrence. Finally, we compared prognoses according to overall survival (OS), disease-specific OS, and disease-free survival (DFS). Results Among 31 patients reclassified to have M1a disease, 21 (67.7%) had supraclavicular lymph node metastasis and 10 (32.3%) had celiac lymph node metastasis. The number of responders was significantly lower for M1a disease based on univariate (p = 0.004) and multivariate (p = 0.011) analyses. Significantly lower survival rates were observed in individuals with M1a disease (median OS, 16.4 vs. 42.7 months; 5-year OS, 10.8% vs. 41.2%). Conclusions M1a node involvement should be differentiated from regional node involvement.

Purpose To explore the role of salvage radiotherapy (RT) for recurrent thymoma as an alternative to surgery. Materials and methods Between 2007 and 2015, 47 patients who received salvage RT for recurrent thymoma at Yonsei Cancer Center were included in this study. Recurrent sites included initial tumor bed (n = 4), pleura (n = 19), lung parenchyma (n = 10), distant (n = 9), and multiple regions (n = 5). Three-dimensional conformal and intensity-modulated RT were used in 29 and 18 patients, respectively. Median prescribed dose to gross tumor was 52 Gy (range, 30 to 70 Gy), with equivalent doses in 2-Gy fractions (EQD2). We investigated overall survival (OS), progression-free survival (PFS), and patterns of failure. Local failure after salvage RT was defined as recurrence at the target volume receiving >50% of the prescription dose. Results Median follow-up time was 83 months (range, 8 to 299 months). Five-year OS and PFS were 70% and 22%, respectively. The overall response rate was 97.9%; complete response, 34%; partial response, 44.7%; and stable disease, 19.1%. In multivariate analysis, histologic type and salvage RT dose (≥52 Gy, EQD2) were significantly associated with OS. The high dose group (≥52 Gy, EQD2) had significantly better outcomes than the low dose group (5-year OS: 80% vs. 59%, p = 0.046; 5-year PFS: 30% vs. 14%, p=0.002). Treatment failure occurred in 34 patients; out-of-field failure was dominant (intra-thoracic recurrence 35.3%; extrathoracic recurrence 11.8%), while local failure rate was 5.8%. Conclusion Salvage RT for recurrent thymoma using high doses and advanced precision techniques produced favorable outcomes, providing evidence that recurrent thymoma is radiosensitive.

Purpose Early hypopharyngeal squamous cell carcinoma (HPSCC) is a rarely diagnosed disease, for which the optimal treatment has not been defined yet. We assessed patterns of failure and outcomes in early HPSCC treated with various therapeutic approaches to identify its optimal treatment. Materials and methods Thirty-six patients with stage I (n = 10) and II (n = 26) treated between January 1992 and March 2014 were reviewed. Patients received definitive radiotherapy (RT) (R group, n = 10), surgery only (S group, n = 19), or postoperative RT (PORT group, n = 7). All patients in both the R and PORT groups received elective bilateral neck irradiation. In the S group, 7 patients had ipsilateral and 8 had bilateral dissection, while 4 patients had no elective dissection. Results At a median follow-up of 48 months, the 5-year locoregional control (LRC) rate was 65%. Six patients had local failure, 1 regional failure (RF), 3 combined locoregional failures, and 2 distant failures. There was no difference in 5-year LRC among the R, S, and PORT groups (p = 0.17). The presence with a pyriform sinus apex extension was a prognosticator related to LRC (p = 0.01) in the multivariate analysis. Patients with a bilaterally treated neck showed a trend toward a lower RF rate (p = 0.08). Conclusion This study shows that patients with early stage HPSCC involving the pyriform sinus apex might need a tailored approach to improve LRC. Additionally, our study confirms elective neck treatment might have an efficacious role in regional control.

PURPOSE We investigated (18)F-fluorodeoxyglucose positron emission tomography (PET)-derived parameters as prognostic indices for disease progression and survival in locally advanced nasopharyngeal carcinoma (NPC) and the effect of high-dose radiotherapy for a subpopulation with PET-based poor prognoses. MATERIALS AND METHODS Ninety-seven stage III and Iva-b NPC patients who underwent definitive treatment and PET were reviewed. For each primary, nodal, and whole tumor, maximum standardized uptake value, metabolic tumor volume, and total lesion glycolysis (TLG) were evaluated. RESULTS Based on the C-index (0.666) and incremental area under the curve (0.669), the whole tumor TLGwas the most useful predictorfor progression-free survival (PFS); thewhole tumor TLG cut-off value showing the best predictive performance was 322.7. In multivariate analysis, whole tumor TLG was a significant prognostic factor for PFS (hazard ratio [HR], 0.3; 95% confidence interval [CI], 0.14 to 0.65; p=0.002) and OS (HR, 0.29; 95% CI, 0.11 to 0.79; p=0.02). Patients with low whole tumor TLG showed the higher 5-year PFS in the subgroup for only patients receiving intensity modulated radiotherapy (77.4% vs. 53.0%, p=0.01). In the subgroup of patients with high whole tumor TLG, patients receiving an EQD2 ≥ 70 Gy showed significantly greater complete remission rates (71.4% vs. 33.3%, p=0.03) and higher 5-year OS (74.7% vs. 19.6%, p=0.02). CONCLUSION Our findings demonstrated that whole tumor TLG could be an independent prognostic factor and high-dose radiotherapy could improve outcomes for NPC showing high whole tumor TLG.

Purpose We compared the treatment results and toxicity in nasopharyngeal carcinoma (NPC) patients treated with concurrent chemotherapy (CCRT) alone (the CRT arm) or neoadjuvant chemotherapy followed by CCRT (the NCT arm). Materials and methods A multi-institutional retrospective study was conducted to review NPC patterns of care and treatment outcome. Data of 568 NPC patients treated by CCRT alone or by neoadjuvant chemotherapy followed by CCRT were collected from 15 institutions. Patients in both treatment arms were matched using the propensity score matching method, and the clinical outcomes were analyzed. Results After matching, 300 patients (150 patients in each group) were selected for analysis. Higher 5-year locoregional failure-free survival was observed in the CRT arm (85% vs. 72%, p=0.014). No significant differences in distant failure-free survival (DFFS), disease-free survival (DFS), and overall survival were observed between groups. In subgroup analysis, the NCT arm showed superior DFFS and DFS in stage IV patients younger than 60 years. No significant difference in compliance and toxicity was observed between groups, except the radiation therapy duration was slightly shorter in the CRT arm (50.0 days vs. 53.9 days, p=0.018). Conclusion This study did not show the superiority of NCT followed by CCRT over CCRT alone. Because NCT could increase the risk of locoregional recurrences, it can only be considered in selected young patients with advanced stage IV disease. The role of NCT remains to be defined and should not be viewed as the standard of care.

Purpose The purpose of this study was to evaluate the clinical outcomes of patients treated with radiotherapy (RT) for a carcinoma of the external auditory canal (EAC) and middle ear. Materials and methods The records of 32 patients who received RT from 1990 to 2013 were reviewed retrospectively. The Pittsburgh classification was used to stage all the cancers (early stage, T1/T2 [n=12]; advanced stage, T3/T4 or N positive [n=20]). Twenty-one patients (65.6%) were treated with postoperative RT and 11 patients (34.4%) were treated with definitive RT. The median radiation doses for postoperative and definitive RT were 60 Gy and 64.8 Gy, respectively. Chemotherapy was administered to seven patients (21.9%). Results The 5-year overall survival and disease-free survival rates for all patients were 57% and 52%, respectively. The disease control rates for the patients with early stage versus advanced stage carcinomawere 55.6% (5/9) and 50% (6/12) in the postoperative RT group and 66.7% (2/3) and 37.5% (3/8) in the definitive RT group, respectively. Overall, 15 cases (14 patients, 46.7%) experienced treatment failure; these failures were classified as local in four cases, regional in one case, and distant in 10 cases. The median follow-up period after RT was 51 months (range, 7 to 286 months). Conclusion Patients with early stage carcinoma achieved better outcomes when definitive RT was used. Advanced stage carcinoma patients experienced better outcomes with postoperative RT. The high rate of distant failure after RT, with or without surgery, reflected the lack of a consensus regarding the best therapeutic approach for treating carcinoma of the EAC and middle ear.

PURPOSE The purpose of this study was to evaluate the benefits of adjuvant treatment for curatively resected thoracic esophageal squamous cell carcinoma (ESCC) and determine the optimal adjuvant treatments. MATERIALS AND METHODS One hundred ninety-five patients who underwent a curative resection for thoracic ESCC between 1994 and 2014 were reviewed retrospectively. Postoperatively, the patients received no adjuvant treatment (no-adjuvant group, n=68), adjuvant chemotherapy (AC group, n=62), radiotherapy (RT group, n=41), or chemoradiotherapy (CRT group, n=24). Chemotherapy comprised cisplatin and 5-fluorouracil administration every 3 weeks. The median RT dose was 45.0 Gy (range, 34.8 to 59.4 Gy). The overall survival (OS), disease-free survival (DFS), locoregional recurrence (LRR), and distant metastasis (DM) rates were estimated. RESULTS At a median follow-up duration of 42.2 months (range, 6.3 to 215.2 months), the 5-year OS and DFS were 37.6% and 31.4%, respectively. After adjusting for other clinicopathologic variables, the AC and CRT groups had a significantly better OS and DFS compared to the no-adjuvant group (p < 0.05). The LRR rate was significantly lower in the RT and CRT groups than in the no-adjuvant group (p < 0.05), whereas no significant difference was observed in the AC group. In the no-adjuvant and AC groups, 25% of patients received high-dose salvage RT due to LRR. The DM rates were similar. The anastomotic stenosis and leakage were similar in the treatment groups. CONCLUSION Adjuvant treatment might prolong survival after an ESCC resection, and RT contributes to a reduction of the LRR. Overall, the risks and benefits should be weighed properly when selecting the optimal adjuvant treatment.

Background The purpose of this study was to determine whether pretreatment 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) volumetric parameters add more prognostic information to p16-positive oropharyngeal squamous cell carcinoma (SCC). Methods We retrospectively analyzed 86 patients with p16-positive oropharyngeal SCC who underwent surgery and postoperative radiotherapy (RT) or chemoradiotherapy (CRT). Maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured. Results Higher total MTV (tMTV), nodal MTV (nMTV), and tumor TLG (tTLG) were significantly associated with lower disease-free survival (DFS) (all p < .05) and higher distant metastasis rates (all p < .05). Multivariate analysis of DFS revealed that tMTV (p = .032), nMTV (p = .004), and tTLG (p = .018) were independently significant prognosticators. Conclusion Patients with p16-positive disease with high metabolic tumor burden were associated with higher distant metastasis rates, translating into worse survival. These patients may not be optimal candidates for treatment deintensification. © 2016 Wiley Periodicals, Inc. Head Neck, 2016

Background The purpose of this study was to assess the efficacy and safety of induction chemotherapy with docetaxel-S-1, and radiotherapy (RT) with concurrent daily cisplatin in locally advanced head and neck carcinoma. Method Fifty patients received 2 cycles of induction chemotherapy with induction chemotherapy with docetaxel and S-1, followed by 7 cycles of RT with concurrent daily cisplatin. Results The most frequent grade 3 to 4 hematologic toxicity was neutropenia (14%). Forty of 50 patients who completed induction chemotherapy with docetaxel and S-1 subsequently started RT with concurrent daily cisplatin, all within 3 to 4 weeks after the start of the second cycle of induction chemotherapy with docetaxel and S-1. The best response to induction chemotherapy with docetaxel and S-1 and after completion of RT with concurrent daily cisplatin was partial response (PR) in 52.5% and complete response in 47.5%, respectively. With a median follow-up of 61 months, 5-year progression-free survival (PFS) and overall survival (OS) were 63.3% and 65.7%, respectively. Conclusion Administration of induction chemotherapy with docetaxel and S-1 before RT with concurrent daily cisplatin chemoradiotherapy (CRT) resulted in a high response rate with good tolerability, and did not compromise subsequent CRT. © 2016 Wiley Periodicals, Inc. Head Neck 38: E1653–E1659, 2016

Induction of vascular hyperpermeability is one of the early vascular responses to radiation exposure and is considered to contribute to subsequent fibrosis and tissue injuries. However, the mechanism underlying radiation-induced hyperpermeability has not yet been clearly elucidated. Here, we provide experimental evidence indicating that mast cells contribute to the increase in vascular permeability for albumin in normal mouse skin after irradiation. Vascular permeability in the skin of C3H mice increased after 2, 15 and 50 Gy irradiation, peaked at 24 h after irradiation and gradually decreased thereafter to the baseline level within 3-10 days. Both the extent and duration of hyperpermeability were dose dependent. We found significant degranulation of mast cells in the skin after 15 Gy irradiation. To further investigate the role of mast cells in the radiation-induced increase in vascular permeability, we measured vascular permeability in the skin of mast cell-deficient mice (WW(v)) and their wild-type littermates at 24 h after irradiation. Vascular permeability in WW(v) mice did not change, whereas that in wild-type mice significantly increased after irradiation. There were no appreciable changes in the total tissue levels of vascular endothelial growth factor or endothelial nitric oxide synthase after 15 Gy irradiation and there was no detectable expression of inducible nitric oxide synthase. Collectively, these results show that exposure to radiation induces vascular hyperpermeability in a dose-dependent manner and that mast cells contribute to this process.

Purpose The purpose of this study is to compare the treatment outcomes for locally advanced resectable hypopharyngeal cancer between organ-preserving chemoradiotherapy (CRT) and surgery followed by radiotherapy (SRT). Materials and Methods We reviewed 91 patients with stage III/IV hypopharyngeal squamous cell carcinoma treated with radiotherapy (RT). In the CRT group (n=34), 18 patients were treated with concurrent CRT and 16 patients with induction chemotherapy plus concurrent CRT. In the SRT group (n=57), six patients were treated with total laryngopharyngectomy, 34 patients with total laryngectomy (TL) and partial pharyngectomy (PP), and 17 patients with PP, which were followed by adjuvant radiotherapy (n=41) or CRT (n=16). The median RT dose was 70 Gy for CRT and 59.4 Gy for SRT. Results Five-year local control (84.1% vs. 90.9%), and disease-free survival (DFS, 51.0% vs. 52.7%) and overall survival (OS, 58.6% vs. 56.6%) showed no significant difference between the CRT and SRT groups. The functional larynx-preservation rate was higher in the CRT group (88.2% vs. 29.8%). Treatment-related toxicity, requiring surgical intervention, occurred more frequently in the SRT group (37% vs. 12%). In the SRT group, TL resulted in a significantly higher DFS than larynx-sparing surgery (63.9% vs. 26.5%, p=0.027). Treatment outcome of the SRT group improved when only patients with TL were considered (n=40); however, 5-year OS (67.1% vs. 58.6%, p=0.830) and DFS (63.9% vs. 51.0%, p=0.490) did not improve significantly when compared to the CRT group. Conclusion Organ preserving CRT provided a treatment outcome that is comparable to SRT for locally advanced hypopharyngeal cancer, while offering an opportunity for functional larynx-preservation and reduced treatment-related toxicity.