Chihiro Kanehira

Evaluation of rectal bleeding factors associated with prostate brachytherapy

PurposeTo analyze rectal bleeding prognostic factors associated with prostate brachytherapy (PB) or in combination with external-beam radiation therapy (EBRT) and to examine dosimetric indications associated with rectal bleeding.Materials and methodsThe study included 296 patients followed up for >36 months (median, 48 months). PB was performed alone in 252 patients and in combination with EBRT in 44 patients. PB combined with EBRT is indicated for patients with a Gleason score >6. The prescribed dose was 144 Gy for monotherapy and 110 Gy for PB + EBRT (44–46 Gy).ResultsAlthough 9.1% who received monotherapy had 2.3% grade 2 rectal bleeding, 36.3% who received combined therapy had 15.9% grade 2 rectal bleeding. Combined therapy was associated with higher incidence of rectal bleeding (P = 0.0049) and higher percentage of grade 2 bleeding (P = 0.0005). Multivariate analysis revealed that R-150 was the only significant factor for rectal bleeding, and modified Radiation Therapy Oncology Group (RTOG) grade in monotherapy and biologically equivalent dose (BED) were significant for combined therapy. Moreover, grade 2 rectal bleeding increased significantly at D90 > 130 Gy.ConclusionAlthough R-150 was the significant prognostic factor for rectal bleeding and modified RTOG rectal toxicity grade, BED was the significant prognostic factor for modified RTOG rectal toxicity grade.

Enhanced four-detector row computed tomography imaging of laryngeal and hypopharyngeal cancers.

Purpose Four-detector row computed tomography (4D CT) enables imaging of the larynx and hypopharynx with high temporal resolution and rapid reformatting of coronal planes. The aim of our study was to assess the usefulness of postcontrast biphasic 4D CT in diagnosing tumor extent. Methods Forty-seven patients with laryngeal or hypopharyngeal cancer were investigated using 4D CT. Two radiologists retrospectively evaluated transverse and reformatted coronal images in both the early and late phases. Results Images in the late phase were superior to those in the early phase in the conspicuity of the depicted lesions. The coronal images facilitated assessment of the craniocaudal extension of tumors and obliteration of the paraglottic space. The maximal diameter of tumors tended to be larger on the coronal image than on the transverse image. Conclusions Images in the late phase were more informative than images in the early phase to demonstrate tumor extension. Reformatted coronal imaging was useful in evaluating craniocaudal extension.

Skin Reactions after Breast-conserving Therapy and Prediction of Late Complications Using Physiological Functions.

BackgroundThe temperature of the skin remains elevated long after breast-conserving treatment with irradiation, perhaps because evaporative cooling is impaired. We investigated physiological changes of the irradiated skin and reevaluated the radiosensitivity of sweat glands on a functional basis to determine whether severe complications can be predicted.MethodsBreast and axillary skin temperatures were measured with thermography and sweat production in response to local thermal stimuli was measured on the basis of changes in electrical skin resistance with a bridge circuit in 45 women before, during, and after breast irradiation for breast cancer.ResultsBreast and axillary skin temperatures were significantly increased after irradiation. In response to cutaneous thermal stimuli, the electric skin resistance of nonirradiated areas decreased significantly because of sweating, but that of irradiated areas was unchanged.ConclusionImpairment of sweating may play an important role in skin damage after irradiation. Although glandular tissue is not usually radiosensitive, the results of our functional assessment suggest that sweat glands are more radiosensitive than expected.

Pulmonary Metastases After Low-Dose-Rate Brachytherapy for Localized Prostate Cancer

Purpose To analyze unusual events and focus discussion on pulmonary metastasis in particular after low-dose-rate brachytherapy (LDR-BT) for prostate cancer (PCa). Materials and Methods A total of 616 consecutive patients who had undergone LDR-BT for clinically localized PCa at Jikei University Hospital between October 2003 and April 2010 were enrolled in this study. Follow-up information was summarized, and patterns of biochemical recurrence and clinical outcome were investigated. Results Disease risk was stratified as low-risk in 231 patients, intermediate-risk in 365, and high-risk in 20, respectively. Of these patients, 269 (43.7%) had received hormonal therapy (HT) in combination with LDR-BT, and 80 (13.0%) had received external beam radiotherapy (EBRT). Average dosimetric parameter values with and without EBRT were 95.3% and 94.2% for V100, 132.8 Gy and 164.2 Gy for D90, and 180.6 Gy2 and 173.7 Gy2 for the biologically effective dose. Biochemical recurrence was noted in 14 patients (6.1%) in the low-risk group, 25 patients (6.8%) in the intermediate-risk group, and 6 patients (30.0%) in the high-risk group, respectively. In these cases of biochemical recurrence, 9 (64.3%), 13 (52.0%), and 4 patients (66.7%) in each respective risk group showed signs of clinical recurrence. Five patients (19.2%) with clinical recurrence developed pulmonary metastases, of which 4 were isolated lesions. All tumors responded favorably to subsequent HT. Conclusions LDR-BT for biologically aggressive PCa may be linked to possible pulmonary metastasis owing to tumor dissemination during seed implantation. This information is important in planning adequate treatment for these patients.