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Aims To evaluate the pattern of locoregional recurrence (LRR) after pancreaticoduodenectomy in patients with distal extrahepatic cholangiocarcinoma (DEHC) and to identify an optimal target volume for elective nodal irradiation. Materials and methods We analysed the medical records of DEHC patients who underwent pancreaticoduodenectomy and had LRR between 1991 and 2015. Among these patients, 30 received adjuvant chemotherapy alone, 14 underwent radiotherapy with or without chemotherapy and 28 received no treatment. After reviewing computed tomography or magnetic resonance imaging scans, the sites of LRR were identified and mapped to the corresponding locations on the representative computed tomography images. Results In total, 136 LRRs were identified in 72 patients from four institutions. Local recurrences were observed at 44 sites (32.4%): tumour bed in 15, choledochojejunostomy in 25 and pancreaticojejunostomy in four. Regional recurrences were observed at 92 sites (67.6%); the most common site was the portal vein area (n = 18), followed by the para-aortic area (n = 17). Based on the mapped plots of regional recurrence, a clinical target volume covering 90% of regional recurrences was generated using the appropriate margin for the vascular structures of the portal vein, celiac axis, superior mesenteric artery, left gastric artery and aorta. Conclusions Given the pattern of LRR, we showed that the nodal clinical target volume based on vascular structures could appropriately cover high-risk regions of nodal involvement. These findings may help physicians construct a target volume in postoperative radiotherapy for DEHC patients undergoing pancreaticoduodenectomy.

Background To investigate outcomes of salvage whole-brain radiotherapy (WBRT) for recurrent brain metastases (BM) from breast cancer (BC), to identify prognostic factors of overall survival (OS), and to propose a novel prognostic classification for OS in these patients. Materials and methods We identified 54 patients who had received salvage WBRT as the second brain-focused treatment for recurrent BM from BC (2000–2014). The median follow-up duration was 4.9 months. A recursive partitioning analysis (RPA) was conducted to develop a model to predict OS at the time of salvage WBRT. Results The median OS was 6.8 months. OS according to BC-specific graded prognostic assessment (breast-GPA), modified breast-GPA, and updated breast-GPA did not represent our cohort. In the multivariate analysis, a long time before salvage WBRT (≥16 months), control of primary BC or extracranial metastases, systemic treatment after salvage WBRT, and administration of a biologically effective dose for an α/β of 10 Gy (BED10) of salvage WBRT >37.5 Gy showed superior OS. We proposed three RPA classes based on the control of both primary BC and extracranial metastasis and BED10 of salvage WBRT: class I, class II, and class III. In this model, patients with class I experienced the best OS (34.6 months; class II, 5.0 months; class III, 2.4 months; P, Highlights • Multicenter retrospective study of salvage WBRT for recurrent brain metastasis. • Subsequent use of systemic treatment after salvage WBRT showing better OS. • Limitations of previous graded prognostic assessments for recurrent brain metastasis. • Novel RPA classification consisting of four simple clinical factors predicts OS.

This study evaluated the prognostic value of leukocyte, lymphocyte, and neutrophil counts in anal cancer patients undergoing concurrent chemoradiotherapy (CCRT). Multi-institutional retrospective data review included 148 non-metastatic anal cancer patients treated with definitive CCRT with 5-fluorouracil plus mitomycin C between the year 2001 and 2019. The median radiation dose to the primary tumor was 54 Gy with a median pelvic dose of 45 Gy. Median follow-up duration was 56 months, and complete blood cell counts were analyzed from baseline to 1 year after the completion of radiotherapy. Although most patients showed a normal number of blood cells before treatment, 6.1% and 4.1% of patients showed leukocytosis (> 10,000/μl) and neutrophilia (> 7500/μl), respectively. After the initiation of treatment, seven patients (4.7%) displayed grade 4 lymphopenia (

To identify the risk factors leading to new brain metastases (BM) following brain-directed treatment for initial BM resulting from breast cancer (BC). In this multi-institutional study, 538 BC patients with available follow-up imaging after brain-directed treatment for initial BM were analyzed. Tumor molecular subtypes were classified as follows: hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2−, n = 136), HER2-positive (HER2+, n = 253), or triple-negative BC (TNBC, n = 149). In 37.4% of patients, new BM emerged at a median of 10.5 months after brain-directed treatment for initial BM. The 1-year actuarial rate of new BM for HR+/HER2−, HER2+, and TNBC were 51.9%, 44.0%, and 69.6%, respectively (p = 0.008). Initial whole-brain radiotherapy (WBRT) reduced new BM rates (22.5% reduction at 1 year, p 4) (p

Introduction The purpose of this study was to evaluate the outcomes of upfront surgery followed by radiation therapy (RT) for ipsilateral supraclavicular (SCN) and/or internal mammary (IMN) node-positive breast cancer. Materials and Methods One hundred fifty-eight patients were included; among these, 91 patients were SCN-positive, 54 were IMN-positive, and 13 were SCN- and IMN-positive. Patients underwent breast conserving surgery (n = 74) or mastectomy (n = 84) followed by systemic therapy, and adjuvant RT to whole breast/chest wall with or without regional nodal RT. Regarding regional treatments for SCN and IMN, SCN excision was performed in 59 (37.3%) patients, IMN excision in 10 (6.3%) patients, SCN RT in 143 (90.5%) patients, and IMN RT in 68 (43.0%) patients. Results The median duration of follow-up was 72 months (range, 7-182 months). There were 20 locoregional recurrences and 45 distant metastases. In-field failure was observed only in SCN (n = 8), and 6 of these patients initially underwent SCN excision. The 5-year locoregional recurrence-free survival, disease-free survival (DFS), and overall survival rates were 87.3%, 71.6%, and 89.7%, respectively. Neither SCN excision nor SCN RT dose ≥ 54 Gy improved locoregional control (P = .927 and P = .693, respectively) or DFS (P = .394 and P = .686, respectively). Having ≥ 10 involved axillary lymph nodes was the only independent prognosticator for DFS after adjusting for covariates (P = .003). Conclusion Regional control rate in initially involved SCN and/or IMN was acceptable in patients treated with upfront surgery followed by systemic therapy plus adjuvant RT. More aggressive regional therapy such as SCN excision did not improve locoregional control or survival.

PurposeTo evaluate the role of postmastectomy radiation therapy (PMRT) in patients with node-negative breast cancer of 5cm or larger tumors undergoing mastectomyMaterials and MethodsMedical records of 274 patients from 18 institutions treated with mastectomy between January 2000 and December 2016 were retrospectively reviewed. Among these, 202 patients underwent PMRT, while 72 did not. Two hundred and forty-one patients (88.0%) received systemic chemotherapy, and 172 (62.8%) received hormonal therapy. Patients receiving PMRT were younger, more likely to have progesterone receptor-positive tumors, and received adjuvant chemotherapy more frequently compared with those without PMRT (p

PurposeThe purpose of this study was to investigate the displacement of surgical clips in the excision cavity during whole breast irradiation following breast-conserving surgery (BCS) with or without acellular dermal matrix (ADM) insertion, and to analyze clinicopathologic factors associated with the displacement of surgical clips.Materials and MethodsFrom 2016 to 2017, 100 consecutive breast cancer patients who underwent BCS with the placement of surgical clips (superior, inferior, medial, lateral, and deep sides) in the tumor bed were included in this study. All patients took first planning computed tomography (CT) scan (CT 1) before whole breast irradiation and second CT scan (CT 2) before boost irradiation. Between two sets of planning CT, the displacement of surgical clips was calculated from the ΔX (lateral–medial), ΔY (anterior–posterior), ΔZ (superior–inferior), and three-dimensional (3D) directions. Patients were divided into two groups according to the breast volume replacement with ADM: group A with ADM and group B without ADM.ResultsThe means and 1 standard deviations of 3D displacement for superior, inferior, medial, lateral and deep clips were 5.2±2.9, 5.2±3.2, 5.6±4.5, 5.6±4.3, and 4.9±4.9 mm in entire cohort (n=100); 5.6±2.6, 6.0±3.5, 6.7±5.8, 6.7±5.7, and 6.1±7.4 mm in group A (n=38); 4.9±3.1, 4.8±3.0, 5.0±3.5, 5.0±2.9, and 4.3±2.8 mm in group B (n=62), respectively. The 3D displacements of group A were longer than those of group B, but only significant difference was observed in lateral clip (p=0.047).ConclusionThis study demonstrated displacement of surgical clips during whole breast irradiation in patients with ADM insertion. For patients who had breast volume replacement using ADM, adaptive boost planning should be considered.

Objectives: To evaluate the CT findings of acute radiation pneumonitis (RP) in breast cancer patients undergoing post-operative radiotherapy, and to analyze clinicodosimetric factors associated with acute RP. Methods: Between 2015 and 2017, 61 patients with breast cancer who underwent follow-up chest CT at 3 months after radiotherapy were analyzed. The degree of acute RP on CT was evaluated by the change of extent and scoring system (grade 0, no RP; Grade 1, ground-glass opacities (GGOs); Grade 2, GGOs and/or consolidations; Grade 3, clear focal consolidation; Grade 4, dense consolidation). The dosimetric parameters were calculated from the dose–volume histogram of RT. Results: The acute RP on CT was scored as follows: Grade 0, in 37.7%, Grade 1 in 13.1%, Grade 2 in 44.3%, and Grade 3 in 4.9%. The median extent of RP in patients with Grades 1 to 3 was 6.2 ml (range, 0.2–95.9). There were no clinicodosimetric factors significantly associated with the presence of RP or its severity. One patient developed symptomatic RP. Conclusion: This study showed no correlation between acute RP and clinicodosimetric factors, and acute RP based on CT findings were much more common than symptomatic RP. Advances in knowledge: CT findings of acute RP or extent of RP were not significantly related to clinicodosimetric factors in breast cancer patients.

Background/aim To present the variations in the target delineation and the planning results of intensity-modulated radiation therapy (IMRT) for breast cancers. Patients and methods We requested the target volumes and organs at risk delineation for two cases of left breast cancers, and evaluated the IMRT plans including the supraclavicular and internal mammary node irradiation. Results Twenty-one institutions participated in this study. Differences in the planning target volume among institutions reached up to three-times for breast-conserving surgery (BCS) case and five-times for mastectomy case. Mean heart doses ranged from 3.3 to 24.1 Gy for BCS case and from 5.0 to 26.5 Gy for mastectomy case. Ipsilateral lung volumes receiving more than 20 Gy ranged from 4.7 to 57.4% for BCS case and from 16.4 to 55.5% for mastectomy case. Conclusion There were large variations in the target delineation and planning results of IMRT for breast cancers among institutions. Considering the increased use of breast IMRT, more standardized protocols are needed.

To evaluate the role of adjuvant radiotherapy (RT) after curative resection in patients with extrahepatic bile duct (EHBD) cancer.Between January 2000 and December 2015, 1475 patients with EHBD cancer who underwent curative resection were accrued from 14 institutions in Korea. Among these, 959 patients did not receive any adjuvant therapy (RT(-) group), while 516 underwent postoperative RT with or without chemotherapy (RT(+) group).The median age was 67 years. Nodal involvement was present in 482 patients (32.7%), and resection margin was involved in 293 patients (19.9%). RT(+) group had more patients with proximal tumours, advanced tumours, nodal involvement, perineural invasion, and involved resection margin than RT(-) group (all p 0.001). With a median follow-up of 36 months, there were 211 locoregional recurrences, 307 distant metastases and 322 combined locoregional and distant failures. On multivariate analysis incorporating age, tumour location, differentiation, pT classification, pN classification, perineural invasion and resection margin, adjuvant RT was associated with improved overall survival (hazard ratio, 0.74; 95% confidence interval, 0.63-0.86; p 0.001). When RT(+) group was separated into RT alone, concurrent chemoradiotherapy (CCRT) and CCRT followed by chemotherapy, the greatest benefit was observed in patients treated with CCRT followed by chemotherapy (hazard ratio, 0.52; 95% confidence interval, 0.41-0.68).Adjuvant RT combined with chemotherapy improved survival outcomes of resected EHBD cancer patients. Considering the greatest benefit observed in patients receiving CCRT followed by chemotherapy, a randomised controlled trial comparing chemotherapy alone and CCRT followed by chemotherapy is urgently needed.

Purpose To evaluate the diagnostic accuracy of computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography/computed tomography (PET/CT) in predicting pelvic lymph node (LN) metastases in patients with cervical cancer. Materials and methods From January 2009 to March 2015, 114 patients with FIGO stage IA1-IIB uterine cervical cancer who underwent hysterectomy with pelvic lymphadenectomy and took CT, MRI, and PET/CT before surgery were enrolled in this study. The criteria for LN metastases were a LN diameter ≥1.0 cm and/or the presence of central necrosis on CT, a LN diameter ≥1.0 cm on MRI, and a focally increased FDG uptake on PET/CT. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for pelvic LN metastases were estimated. Results The sensitivity, specificity, PPV, NPV, and accuracy for detection of pelvic LN metastases were 51.4%, 85.9%, 41.3%, 90.1%, and 80.3% for CT; 24.3%, 96.3%, 56.3%, 86.8%, and 84.6% for MRI; and 48.6%, 89.5%, 47.4%, 90.0%, and 82.9% for PET/CT, respectively. The sensitivity of PET/CT and CT was higher than that of MRI (p=0.004 and p= 0.013, respectively). The specificity of MRI was higher than those of PET/CT and CT (p=0.002 and p=0.001, respectively). The difference of specificity between PET/CT and CT was not statistically significant (p=0.167). Conclusion These results indicate that preoperative CT, MRI, and PET/CT showed low to moderate sensitivity and PPV, and moderate to high specificity, NPV, and accuracy. More efforts are necessary to improve sensitivity of imaging modalities in order to predict pelvic LN metastases.

Background: For decades, conventional fractionated whole breast irradiation (CF-WBI) was used after breast conserving surgery (BCS). Pivotal phase-3 trials on hypofractionated-WBI (HF-WBI) showed i...

Background: To examine the factors associated with ovarian failure (OF) and assess the effectiveness of ovarian transposition (OT) before pelvic irradiation for preserving ovarian function in patients with cervical cancer (CC) undergoing hysterectomy.Methods: During 2003-2017, patients who underwent hysterectomy with preservation of one or both ovaries were retrospectively enrolled. Patients were divided into 4 groups, depending on whether radiotherapy (RT) and OT were performed: group 1, RT(+) and OT(+); group 2, RT(+) and OT(-); group 3, RT(-) and OT(+); group 4, RT(-) and OT(-). OF was defined as serum follicle-stimulating hormone levels of ≥30 mIU/mL.Results: Sixty-six patients (59 [89.4%] invasive CC and 7 [10.6%] cervical intraepithelial neoplasia) were included. The 2-year ovarian failure-free survival (OFFS) rate was 61.4% (95% confidence interval (CI) 37.8–86.0), 0%, 91.7% (95% CI 76.0–100), and 75.8% (95% CI 58.2–93.4) for groups 1, 2, 3, and 4, respectively. In groups 1 and 2 receiving RT, OT and combination of external beam radiotherapy and vaginal brachytherapy (VB) were associated with OF on multivariate analysis (MVA) (p-value=0.002 and 0.046, respectively). In groups 3 and 4 without RT, older age (40 years) and OT did not affect OF; however, the number of remaining ovaries was independently associated with OF in MVA (p=0.035).Conclusions: OT could effectively preserve ovarian function in adjuvant RT-treated patients. Lower location of transposed ovary with VB boost was significantly associated with early OF.

Purpose The purpose of this study is to evaluate the treatment outcomes of adjuvant radiotherapy using vaginal brachytherapy (VB) with a lower dose per fraction and/or external beam radiotherapy (EBRT) following surgery for patients with stage I endometrial carcinoma. Materials and methods The subjects were 43 patients with the International Federation of Gynecology and Obstetrics (FIGO) stage I endometrial cancer who underwent adjuvant radiotherapy following surgery between March 2000 and April 2014. Of these, 25 received postoperative VB alone, while 18 received postoperative EBRT to the whole pelvis; 3 of these were treated with EBRT plus VB. The median EBRT dose was 50.0 Gy (45.0-50.4 Gy) and the VB dose was 24 Gy in 6 fractions. Tumor dose was prescribed at a depth of 5 mm from the cylinder surface and delivered twice per week. Results The median follow-up period for all patients was 57 months (range, 9 to 188 months). Five-year disease-free survival (DFS) and overall survival (OS) for all patients were 92.5% and 95.3%, respectively. Adjuvant radiotherapy was performed according to risk factors and stage IB, grade 3 and lymphovascular invasion were observed more frequently in the EBRT group. Five-year DFS for EBRT and VB alone were 88.1% and 96.0%, respectively (p = 0.42), and 5-year OS for EBRT and VB alone were 94.4% and 96%, respectively (p = 0.38). There was no locoregional recurrence in any patient. Two patients who received EBRT and 1 patient who received VB alone developed distant metastatic disease. Two patients who received EBRT had severe complications, one each of grade 3 gastrointestinal complication and pelvic bone insufficiency fracture. Conclusion Adjuvant radiotherapy achieved high DFS and OS with acceptable toxicity in stage I endometrial cancer. VB (with a lower dose per fraction) may be a viable option for selected patients with early-stage endometrial cancer following surgery.

Purpose: To evaluate the treatment outcomes of radiotherapy (RT) for breast cancer with ipsilateral supraclavicular (SCL) and/or internal mammary (IMN) lymph node involvement. Methods: A total of 353 patients from 11 institutions were included. One hundred and thirty-six patients had SCL involvement, 148 had IMN involvement, and 69 had both. All patients received neoadjvant systemic therapy followed by breast conserving surgery or mastectomy, and postoperative RT to whole breast/chest wall. As for regional lymph node irradiation, SCL RT was given to 344 patients, and IMN RT to 236 patients. The median RT dose was 50.4 Gy. Results: The median follow-up duration was 61 months (range, 7-173). In-field progression was present in SCL (n=20) and/or IMN (n=7). The 5-year disease-free survival (DFS) and overall survival rates were 57.8% and 75.1%, respectively. On multivariate analysis, both SCL/IMN involvement, number of axillary lymph node ≥4, triple negative subtype, and mastectomy were significant adverse prognosticators for DFS (p = 0.022, 0.001, 0.001, and 0.004, respectively). Regarding the impact of regional nodal irradiation, SCL RT dose ≥54 Gy was not associated with DFS (5-yr rate, 52.9% vs. 50.9%, p = 0.696) in SCL-involved patients, and the receipt of IMN RT was not associated with DFS (5-yr rate, 56.1% vs. 78.1%, p = 0.099) in IMN-involved patients. Conclusion: Neoadjuvant chemotherapy followed by surgery and postoperative RT achieved an acceptable in-field regional control rate in patients with SCL and/or IMN involvement. However, a higher RT dose to SCL or IMN RT was not associated with the improved DFS in these patients. Citation Format: Kim K, Jeong Y, Shin KH, Kim JH, Ahn SD, Kim SS, Suh C-O, Kim YB, Choi DH, Park W, Cha J, Chun M, Lee DS, Lee SY, Kim JH, Park HJ. Impact of regional nodal irradiation for breast cancer patients with supraclavicular and/or internal mammary lymph node involvement: A multicenter, retrospective study (KROG 16-14) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-12-12.

Background For decades, conventionally fractionated whole breast irradiation (CF-WBI) was used after breast conserving surgery (BCS). Pivotal phase 3 trials on hypofractionated-WBI (HF-WBI) showed its non-inferiority as compared to CF-WBI. However, younger patients ( Methods Between 2010 and 2016, a total of 786 patients aged less than 60 years old with early stage breast cancer were treated with postoperative WBI after BCS in three breast cancer centers: 340 underwent HF-WBI while 446 were treated with CF-WBI. Acute toxicity was evaluated at the end of WBI. Late toxicity was evaluated at 6, 12, 24, and 36 months. Results At univariate logistic analysis, hypofractionation showed a significant protective effect in terms of acute edema (p = 0.0001), acute wet desquamation (p = 0.009), chronic edema (p = 0.0001), chronic erythema/pigmentation (p = 0.0001), and breast fibrosis (p = 0.0002). At multivariate logistic analysis, hypofractionation was independent significant factor for acute edema (OR 0.09, 95% CI 0.02 to 0.48; p = 0.005), acute wet desquamation (OR 0.07, 95% CI 0.009 to 0.59; p = 0.014), and chronic edema (OR 0.18, 95% CI 0.04 to 0.75; p = 0.018). Significant association between individual characteristics and toxicity (grade 2 or more) are summarized in Table. Table . 215P Toxicity N Protective factor p-value OR (95%CI) Risk factor p-value OR (95%CI) Acute edema 43 Hypofractionation Dmax/Prescribed dose° 0.0001 0.001 0.09 (0.03-0.30) 0.16 (0.06-0.46) Chemotherapy 0.002 2.63 (1.42-4.90) Chronic edema 50 Hypofractionation Dmax/Prescribed dose° 0.0001 0.003 0.20 (0.09-0.44) 0.31 (0.14-0.66) EIC presence Boost dose >10 Gy Breast size >492 cc 0.0001 0.032 0.003 3.0 (1.66-5.46) 9.02 (1.21-67.45) 2.67 (1.41-5.05) Acute erythema/ pigmentation 163 HER2 positive status Trastuzumab 0.002 0.022 0.30 (0.14-0.63) 0.39 (0.18-0.87) Smoking habits Boost dose >10 Gy Breast size >492 cc 0.001 0.038 0.002 2.14 (1.37-3.32) 2.60 (1.06-6.41) 1.78 (1.24-2.54) Chronic erythema/ pigmentation 110 Hypofractionation Dmax/Prescribed dose° 0.0001 0.001 0.40 (0.25-0.63) 0.45 (0.28-0.73) EIC presence Positive FSM Boost dose >10 Gy Breast size >492 cc 0.0001 0.002 0.007 0.034 2.39 (1.54-3.71) 3.47 (1.56-7.71) 15.43 (2.08-114.3) 1.58 (1.04-2.41) Acute wet desquamation 20 Hypofractionation Dmax/Prescribed dose° 0.009 0.047 0.14 (0.03-0.61) 0.29 (0.08-0.99) - - - Breast fibrosis 117 Hypofractionation Tumor grade Ki67 index Dmax/Prescribed dose° 0.0002 0.022 0.023 0.017 0.44 (0.29-0.68) 0.53 (0.31-0.92) 0.60 (0.38-0.93) 0.58 (0.37-0.91) EIC presence Boost dose >10 Gy Breast size >492 cc 0.0001 0.022 0.0001 3.03 (1.99-4.62) 6.76 (2.04-22.45) 2.84 (1.83-4.41) Conclusions HF-WBI showed significantly improved toxicity outcomes in terms of both acute skin edema and wet desquamation, and chronic skin edema. HF-WBI after BCS should replace CF-WBI independently of age. Legal entity responsible for the study The authors. Funding Has not received any funding. Disclosure All authors have declared no conflicts of interest.

Objective: To generate a map of local recurrences after pancreaticoduodenectomy (PD) for patients with distal extrahepatic cholangiocarcinoma (DEHC) and to evaluate the adequate target volume coverage encompassing the majority of local recurrences when the clinical target volume (CTV) for pancreatic cancer was applied. Methods: We retrospectively reviewed the records of DEHC patients who underwent pancreaticoduodenectomy and had postoperative CT scans acquired between 1991 and 2015 available. The sites of local recurrence were delineated on individual CT scans, and then, mapping was manually performed onto template CT images. Coverage of each site of local recurrence was evaluated by applying the CTV defined according to Radiation Therapy Oncology Group (RTOG) consensus guidelines (CTVRTOG ) for target delineation in the postoperative treatment of pancreatic head cancer. Results: Of the 99 patients, 36 patients had a total of 62 local relapses identifiable by postoperative CT scans; the relapses were the most frequent in the choledochojejunostomy (CJ) site, 11 sites (17.7%); para-aortic area, 10 sites (16.1%), superior mesenteric artery area, 10 sites (16.1%); and portal vein area, 9 sites (14.5%). 21 sites (33.9%) were not covered by the CTVRTOG, and the most common site of local recurrence outside the CTVRTOG was the CJ site. Conclusion: When mapping of local relapses was evaluated according to the CTVRTOG, the choledochojejunostomy site was identified as a high-risk area of local recurrence but was insufficiently covered within the CTVRTOG. These findings may help construct a target volume for postoperative radiotherapy in DEHC. Advances in knowledge: Mapping local recurrences can aid in defining appropriate target volume for postoperative radiotherapy in DEHC.