The Impact of Variation in Bladder Volume on the Doses of Target and Organ-at-Risk in Intensity-Modulated Radiation Therapy for Localized Prostate Cancer

Intensity-modulated radiation therapy (IMRT) has become the mainstay of treatment for localized prostate cancer. In IMRT, minimizing differences between the conditions used during planning CT and daily treatment is important to prevent adverse events in normal tissues. In the present study, we evaluated the impact of variation in bladder volume on the doses to various organs. A total of 35 patients underwent definitive radiotherapy at Saitama Medical Center. A Light Speed RT16 (GE Healthcare) was used for planning and to obtain examination CT images. Such images were acquired after 4 - 6 days of planning CT image acquisition. The IMRT plans were optimized using the planning CT data to satisfy the dose constraints set by our in-house protocols for the PTV and the OARs. The dose distributions were then re-calculated using the same IMRT beams, and checked on examination CT images. It was clear that bladder volume affected the doses to certain organs. We focused on the prostate, bladder, rectum, small bowel, and large bowel. Regression coefficients were calculated for variables that correlated strongly with bladder volume (p < 0.05). We found that variation in bladder volume [cm3] predicted deviations in the bladder V70Gy, V50Gy, and V30Gy [%];the maximum dose to the small bowel [cGy];and the maximum dose to the large bowel [cGy]. The regression coefficients were -0.065, -0.125, -0.180, -10.22, and -9.831, respectively. We evaluated the impacts of such variation on organ doses. These may be helpful when checking a patient’s bladder volume before daily IMRT for localized prostate cancer.

Evaluation of Quality of Life and Psychological Response in Recurrent and Metastatic Tumors Treated with Palliative Radiotherapy

Objective: We evaluated the effects of palliative radiotherapy for cancer recurrence or metastasis on patient QOL and psychophysiology. Materials and Methods: Sixty seven patients who received palliative radiotherapy between 2014 and 2015 were enrolled. Patient diseases were bone metastasis in 51 patients, lymph node metastasis in 7 patients, brain metastasis in 2 patients, local recurrence in 3 patients, and others in 4 patients. Median irradiated dose was 30 Gy in 10 fractions for palliative radiotherapy. We used the questionnaires EORTC-QLQ-C30 and EORTC-QLQ-C15-PAL to evaluate patient QOL and the Hospital Anxiety and Depression Scale to evaluate patient mental healthcare at the start and at the end of radiotherapy. Results: As compared to scores at the start of radiotherapy, at the end of radiotherapy, NRS and face scale significantly decreased. On the other hand, Eastern Cooperative Oncology Group Performance Status did not show any changes during palliative radiotherapy. In functional scales, average scores of RF2 and EF also improved. In symptom scales, average scores of FA, PA, and SL improved. In bone metastasis group, global health status/QOL, PA, and SL significantly improved. There was relationship between anxiety improvement and QOL improvement after palliative radiotherapy. Nausea and vomiting scores of EORTC-QLQ-C15-PAL were associated with the irradiated volume of palliative radiotherapy for pelvic region. Conclusion: Patient QOL of was improved by palliative radiotherapy regardless of PS. The possibility of palliative radiotherapy having a positive influence on patient psychophysiology was also suggested in younger age.