Search

Purpose: We investigated the long-term oncological outcome of high-dose-rate (HDR) multicatheter interstitial brachytherapy (MIB) for adjuvant accelerated partial breast irradiation (APBI) after breast conserving surgery in Japanese patients. Material and methods: Between June 2002 and October 2011, 86 breast cancer patients were treated at National Hospital Organization Osaka National Hospital (trial number of the local institutional review board, 0329). Median age was 48 years (range, 26-73 years). Eighty patients had invasive and 6 patients non-invasive ductal carcinoma. Tumor stage distribution was pT0 in 2, pTis in 6, pT1 in 55, pT2 in 22, and pT3 in one patient, respectively. Twenty-seven patients had close/positive resection margins. Total physical HDR dose was 36-42 Gy in 6-7 fractions. Results: At a median follow-up of 119 months (range, 13-189 months), the 10-year local control (LC) and overall survival rate was 93% and 88%, respectively. Concerning the 2009 Groupe Européen de Curiethérapie-European Society for Therapeutic Radiology and Oncology risk stratification scheme, the 10-year LC rate was 100%, 100%, and 91% for patients considered as low-risk, intermediate-risk, and high-risk, respectively. According to the 2018 American Brachytherapy Society risk stratification scheme, the 10-year LC rate was 100% and 90% for patients 'acceptable' and 'unacceptable' for APBI, respectively. Wound complications were observed in 7 patients (8%). Risk factors for wound complications were the omission of prophylactic antibiotics during MIB, open cavity implantation, and V100 ≥ 190 cc. No grade ≥ 3 late complications (CTCVE version 4.0) were observed. Conclusions: Adjuvant APBI using MIB is associated with favorable long-term oncological outcomes in Japanese patients for low-risk, intermediate-risk, and acceptable groups of patients. [ABSTRACT FROM AUTHOR]

Purpose: Tongue edema is a potential cause of treatment target underdosage in high-dose-rate interstitial brachytherapy (HDR-ISBT) of mobile tongue cancer. To prevent such edema-associated alteration of dosimetry, we developed a special silicon device. In this report we communicate our initial experience with two mobile tongue cancer patients whom we treated using this new device. Material and methods: The device consists of silicone tubes with a fixed width and scalable length depending on tongue size. These tubes are lined and fixed like a palisade, allowing the device to be used also as a template. The device is placed next to the lateral border of the tongue and on the floor of the mouth. In addition, a vinyl template can be placed on the dorsal tongue surface with both devices combined for implantation guidance. Between June and August 2012, two patients with locally confined tongue cancer were treated. Results: Between June and August 2012, two mobile tongue cancer patients classified as cT2N0M0 were treated with HDR-ISBT using the silicone device. They underwent ISBT as monotherapy with fractional doses of 6.0 Gy up to a total physical dose of 54.0 Gy. The D90 (CTV) values of both patients were 6.3 Gy and 6.6 Gy and the D2cc (mandible) values were 3.4 Gy and 2.6 Gy, respectively. At present, both patients remain without local disease recurrence at 60 and 56 months after ISBT, respectively. Conclusions: The described silicone device has the potential to prevent underdosage to the treatment target related to tongue edema. It has been shown to be safe and easy to implement. [ABSTRACT FROM AUTHOR]

Purpose: Advances in three-dimensional image-guided brachytherapy technique allow for using intra-cavitary, intra-cavitary and interstitial brachytherapy (ICIS-BT), and sole interstitial brachytherapy (ISBT) in addition to conventional intra-cavitary brachytherapy (ICBT). However, no consensus has been reached regarding the choice of these techniques. The aim of this study was to propose the size criteria for indication of interstitial techniques. Material and methods: We examined initial gross tumor volume (GTV) at presentation and at each brachytherapy session. Also, dose volume histogram parameters for each modality were compared in 112 patients with cervical cancer treated with brachytherapy (ICBT, 54; ICIS-BT, 11; and ISBT, 47).Results: The average GTV at diagnosis was 80.9 cm3 (range, 4.4-343.2 cm³), which shrank to 20.6 cm³ (25.5% of initial volume, range, 0.0-124.8 cm³) at initial brachytherapy. GTV > 30 cm³ at brachytherapy and high-risk clinical target volume > 40 cm³ were good threshold values for indication of interstitial technique, and tumors with initial GTV > 150 cm³ could be candidates for ISBT. An ISBT dose of 89.10 Gy can be prescribed in equivalent dose in 2 Gy fractions (range, 65.5-107.6 Gy), which was higher than those of ICIS (73.94 Gy, range, 71.44-82.50 Gy) and ICBT (72.83 Gy, range, 62.50-82.27 Gy) (p < 0.0001).Conclusions:Initial tumor volume is an important predictor for indication of ICBT and ICIS-BT. ISBT or at least an interstitial technique is recommended for initial GTV > 150 cm³. [ABSTRACT FROM AUTHOR]

Purpose: We report our study on two patients to highlight the risk of underdosage of the clinical target volume (CTV) due to edema during high-dose-rate interstitial brachytherapy (HDR-ISBT) of mobile tongue cancer. Material and methods: To treat the lateral side of the CTV, flexible applicator tubes were implanted on the mouth floor. Two-dimensional planning was performed using X-ray images for Case 1, and three-dimensional (3D) planning was performed using computed tomography (CT) for Case 2. Prescribed doses for both cases were 54 Gy in nine fractions. Case reports: Case 1 was treated for cancer of the right lateral border of the tongue in 2005. Tongue edema occurred after implantation, and part of the lateral border of the tongue protruded between the applicator tubes. Acute mucosal reaction abated in the protruded area earlier than in the other parts of the CTV. In this case, the tumor recurred in this area 5 months after the treatment. Case 2 was treated for cancer of the left lateral border of the tongue. Because tongue edema occurred in this case also, plastic splints were inserted between the applicator tubes to push the edematous region into the irradiated area. The mucosal surface of the CTV was covered by the 70% isodose, and 100% isodose line for before and after splint insertion. Local control of the tumor was achieved 4 years after treatment. Discussion and conclusions: To ensure sufficient target coverage, 3D image-based planning using CT should be performed, followed by re-planning using repeated CT as needed. Also, the development of devices to prevent protrusion of the edematous tissue outside the target area will help to ensure the full dosing of CTV. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to evaluate the effect of a lead block for alveolar bone protection in image-guided high-dose-rate interstitial brachytherapy for tongue cancer. Material and methods: We treated 6 patients and delivered 5,400 cGy in 9 fractions using a lead block. Effects of lead block (median thickness, 4 mm) on dose attenuation by distance were visually examined using TG-43 formalism-based dose distribution curves to determine whether or not the area with the highest dose is located in the alveolar bone, where there is a high-risk of infection. Dose re-calculations were performed using TG-186 formalism with advanced collapsed cone engine (ACE) for inhomogeneity correction set to cortical bone density for the whole mandible and alveolar bone, water density for clinical target volume (CTV), air density for outside body and lead density, and silastic density for lead block and its' silicon replica, respectively. Results: The highest dose was detected outside the alveolar bone in five of the six cases. For dose-volume histogram analysis, median minimum doses delivered per fraction to the 0.1 cm3 of alveolar bone (D0.1cm3 TG-43, ACE-silicon, and ACE-lead) were 344.3 (range, 262.9-427.4) cGy, 336.6 (253.3-425.0) cGy, and 169.7 (114.9-233.3) cGy, respectively. D0.1cm3 ACE-lead was significantly lower than other parameters. No significant difference was observed between CTV-related parameters. Conclusions: The results suggested that using a lead block for alveolar bone protection with a thickness of about 4 mm, can shift the highest dose area to non-alveolar regions. In addition, it reduced D0.1cm3 of alveolar bone to about half, without affecting tumor dose. [ABSTRACT FROM AUTHOR]

We initiated the first multi-institutional prospective study of accelerated partial breast irradiation for early breast cancer in Japan. Our early clinical results showed that the treatment methods were technically reproducible between institutions and showed excellent disease control at a median follow-up of 26 months in our previous report. At present, total 46 patients from six institutions underwent the treatment regimen from October 2009 to December 2011, and the median follow-up time was 60 months (range, 57-67 months). In 46 patients, we experienced one patient who had rib fracture as a late complication. The dose-volume histogram (DVH) result of this patient was analyzed. The D0.01cc, D0.1cc, and D1cc values of the patient were 913, 817, and 664 cGy per fraction, respectively. These values were the highest values in 46 patients. The average D0.01cc, D0.1cc, and D1cc values of the other 45 patients were 546, 500, and 419, respectively, cGy per fraction. From this result, DVH values showing high-dose irradiated volume (D0.01cc, D0.1cc, and D1cc) seem to be a good predictive factor of rib fracture for accelerated partial breast irradiation. However, further investigation is necessary because of the small number of patients investigated. [ABSTRACT FROM AUTHOR]

The aim of the present study was to elucidate the effect of intratumoral abscess/necrosis (AN) on the outcome of patients with recurrent head and neck cancer (HNC) treated by stereotactic radiotherapy. The records of 67 patients treated with CyberKnife® in four institutes between August 2000 and July 2010 were reviewed. The frequency of AN appeared to be increased in younger postoperative patients with large ulcerative tumors. The AN+ group exhibited a better initial response rate compared with the AN- group (64 vs. 33%, respectively; P=0.04). The 1-year local control rate was 51 and 75% in the AN+ and AN- groups, respectively (P=0.01), while the respective 1-year overall survival rates were 53 and and 71% (P=0.0004). A total of 21 patients (31%) experienced grade ≥ 3 toxicities, and carotid blowout syndrome (CBOS) was found in 11 patients, resulting in 8 deaths. A significantly larger proportion of patients in the AN+ group developed CBOS (8/18; 44%) compared with the AN- group (3/49; 6%) (P=0.001). Therefore, AN may be an important prognostic factor for patients with recurrent HNC, as well as a predictor of lethal toxicity due to CBOS. [ABSTRACT FROM AUTHOR]

Background: This study aimed to elucidate the influence of skin invasion in patients with recurrent head and neck cancer treated with re-irradiation using stereotactic radiotherapy.Materials: We reviewed 104 patients treated using CyberKnife in four institutions.Results: Nine cases of skin invasion were recognized (8.6 %). Larger tumors tended to exhibit skin invasion. The skin invasion (+) group showed a lower response rate (0/9, 0 %) than the skin invasion (-) group (56/95, 59 %) (p = 0.002). The skin invasion (+) group showed lower local control (LC) and progression free survival (PFS) rates, both 0 % at 6 months, than the skin invasion (-) group, which had a LC of 69 % (p = 0.0001) and a PFS of 48 % at 1 year (p = 0.0157). Median survival time and one-year survival rates for the skin invasion (+) and (-) groups were 6.6 vs. 15.3 months and 14 % vs. 59 % (p = 0.0005), respectively. No patient with skin invasion survived more than 14.4 months. The percentage of patients who developed grade 3 or higher toxicity was 44 % in the skin invasion (+) group and 18 % in the skin invasion (-) group (p = 0.14).Conclusions: Skin invasion is an important predictor of poor prognosis in recurrent head and neck cancer after re-irradiation with stereotactic radiation therapy. [ABSTRACT FROM AUTHOR]

Objective: To assess actual rates of late vaginal stenosis and identify predisposing factors for complications among patients with previously untreated cervical cancer following high-dose-rate brachytherapy. Methods: We performed longitudinal analyses of 57 patients using the modified Dische score at 6, 12, 18, 24, 36, and 60 months after treatment, which consisted of 15 interstitial brachytherapys and 42 conventional intracavitary brachytherapys, with a median follow-up time of 36 months (range, 6 to 144 months). Results: More than half of the patients developed grade 1 (mild) vaginal stenosis within the first year of follow-up, and grade 2 (97.5%, moderate) to grade 3 (severe) stenosis gradually increased with time. Actual stenosis rates for grade 1, 2, and 3 were 97.5% (95% confidence interval [CI], 92.7 to 97.5), 60.7% (95% CI, 42.2 to 79.3), and 7.4% (95% CI, 0 to 18.4) at 3 years after treatment. Pallor reaction grade 2-3 at 6 months was only a statistically significant predisposing factor for grade 2-3 late vaginal stenosis 3 years or later with a hazard ratio of 3.48 (95% CI, 1.32 to 9.19; p=0.018) by a multivariate Cox proportional hazard model. Patients with grade 0-1 pallor reaction at 6 months showed a grade ⩾2 vaginal stenosis rate of 53%, whereas the grade 2-3 pallor reaction group achieved a grade ⩾2 vaginal stenosis rate at 3 years at 100% (p=0.001). Conclusion: High-dose-rate brachytherapy was associated with high incidence of late vaginal stenosis. Pallor reaction grade 2-3 at 6 months was predictive of late grade 2-3 vaginal stenosis at 3 years after treatment. These findings should prove helpful for patient counseling and preventive intervention. [ABSTRACT FROM AUTHOR]

Background: In Japan, breast-conserving surgery with closed cavity has generally been performed for breast cancer patients, and accelerated partial breast irradiation (APBI) is considered difficult because Asian females generally have smaller breast sizes than Western females. Therefore, common identification of target and treatment plan method in APBI is required. A prospective multicenter study was conducted in Japan to determine institutional compliance with APBI using high-dose-rate interstitial brachytherapy (ISBT) designed for Japanese female patients. Methods: For this study, 46 patients were recruited at eight institutions from January 2009 to December 2011. The reproducibility of the ISBT-APBI plan was evaluated using three criteria: (1) minimum clinical target volume dose with a clip dose ≥ 6 Gy/fraction, (2) irradiated volume constraint of 40-150 cm3, and (3) uniformity of dose distribution, expressed as the dose non-uniformity ratio (DNR, V150/V100) < 0.35. The ISBT-APBI plan for each patient was considered reproducible when all three criteria were met. When the number of non-reproducible patients was ≤ 4 at study completion, APBI at this institution was considered statistically reproducible. Results: Half of the patients (52 %) had a small bra size (A/B cup). The mean values of the dose-constrained parameters were as follows: Vref, 117 cm3 (range, 40-282), DNR, 0.30 (range, 0.22-0.51), and clip dose, 784 cGy (range, 469-3146). A total of 43/46 treatment plans were judged to be compliant and ISBT-APBI was concluded to be reproducible. Conclusions: This study showed that multi-institutional ISBT-APBI treatment plan was reproducible for small breast patient with closed cavity. [ABSTRACT FROM AUTHOR]

Background: In Japan, breast-conserving surgery with closed cavity has generally been performed for breast cancer patients, and accelerated partial breast irradiation (APBI) is considered difficult because Asian females generally have smaller breast sizes than Western females. Therefore, common identification of target and treatment plan method in APBI is required. A prospective multicenter study was conducted in Japan to determine institutional compliance with APBI using high-dose-rate interstitial brachytherapy (ISBT) designed for Japanese female patients. Methods: For this study, 46 patients were recruited at eight institutions from January 2009 to December 2011. The reproducibility of the ISBT–APBI plan was evaluated using three criteria: (1) minimum clinical target volume dose with a clip dose ≥ 6 Gy/fraction, (2) irradiated volume constraint of 40-150 cm3, and (3) uniformity of dose distribution, expressed as the dose non-uniformity ratio (DNR, V150/V100) < 0.35. The ISBT–APBI plan for each patient was considered reproducible when all three criteria were met. When the number of non-reproducible patients was ≤ 4 at study completion, APBI at this institution was considered statistically reproducible. Results: Half of the patients (52 %) had a small bra size (A/B cup). The mean values of the dose-constrained parameters were as follows: Vref, 117 cm3 (range, 40-282), DNR, 0.30 (range, 0.22-0.51), and clip dose, 784 cGy (range, 469-3146). A total of 43/46 treatment plans were judged to be compliant and ISBT–APBI was concluded to be reproducible. Conclusions: This study showed that multi-institutional ISBT–APBI treatment plan was reproducible for small breast patient with closed cavity. [ABSTRACT FROM AUTHOR]

Purpose: To compare the outcome of our facility with another about the shortened schedule (60 Gy in 10 fractions to 54 Gy in 9 fractions) of high-dose-rate interstitial brachytherapy (HDR ISBT) for mobile tongue cancer. Material and methods: Eighteen patients were treated with HDR ISBT as a monotherapy in dose reduction schedule with some unique technique to determine the border of tumor accuracy (lugol's staining and metal marker), and to minimize adverse effect (lead-lined silicon block) at our facility. Results: The 2-year local and regional control rates and cause-specific survival rate were 82%, 80%, and 83% and moderate to severe late complications occurred in five patients (28%), which were almost the same treatment results achieved by another facility. Conclusions: We recommend 54 Gy in 9 fractions over 7 days as a feasible treatment to reduce patient discomfort in mobile tongue cancer patients. [ABSTRACT FROM AUTHOR]