Incidence of Bladder Cancer in Patients Undergoing Radiotherapy for Prostate Cancer.

INTRODUCTION: Radiotherapeutic treatment of prostate cancer has been validated in terms of efficacy, but its relationship with the occurrence of second pelvic primary malignancy and the relevance of radio-induced toxicity is still under debate. This study analyses the occurrence of second pelvic primary malignancy as well as morbidity secondary to radiotherapy treatment in patients treated for prostate cancer. MATERIAL AND METHODS: Retrospective consecutive descriptive study of 317 patients who received radiotherapy treatment for prostate cancer between 2007 and 2017. Predictor variables, side effects and the appearance of second pelvic primary malignancy during a maximum follow-up of 10 years were collected. We analyse whether there is a significant relationship in the appearance of second pelvic primary malignancy and describe the clinical toxicity presented by the patients. RESULTS: The median age was 62.27 years and the most commonly employed treatment modality was brachytherapy with IMRT (60%). 17 patients (5.4%) developed a second pelvic primary malignancy, with a median time to onset of 58 and 25 months for bladder and colon tumours, respectively. Local recurrence and mortality rates are 8% and 7%, respectively. Statistically significant association is demonstrated for the occurrence of second pelvic primary malignancy and for chronic radioinduced toxicity according to type of radiotherapy χ2 (4) = 16.34; p = 0.003 and χ2 (1) = 6.47; p = 0.011 respectively. CONCLUSIONS: In our series, the occurrence of a second pelvic primary malignancy is statistically associated with the modality of radiotherapy administered and occurrence of chronic adverse effects.

Incidence of Bladder Cancer in Patients Undergoing Radiotherapy for Prostate Cancer

Introduction: Radiotherapeutic treatment of prostate cancer has been validated in terms of efficacy, but its relationship with the occurrence of second pelvic primary malignancy and the relevance of radio-induced toxicity is still under debate. This study analyses the occurrence of second pelvic primary malignancy as well as morbidity secondary to radiotherapy treatment in patients treated for prostate cancer. Material and Methods: Retrospective consecutive descriptive study of 317 patients who received radiotherapy treatment for prostate cancer between 2007 and 2017. Predictor variables, side effects and the appearance of second pelvic primary malignancy during a maximum follow-up of 10 years were collected. We analyse whether there is a significant relationship in the appearance of second pelvic primary malignancy and describe the clinical toxicity presented by the patients. Results: The median age was 62.27 years and the most commonly employed treatment modality was brachytherapy with IMRT (60%). 17 patients (5.4%) developed a second pelvic primary malignancy, with a median time to onset of 58 and 25 months for bladder and colon tumours, respectively. Local recurrence and mortality rates are 8% and 7%, respectively. Statistically significant association is demonstrated for the occurrence of second pelvic primary malignancy and for chronic radioinduced toxicity according to type of radiotherapy χ2 (4) = 16.34; p = 0.003 and χ2 (1) = 6.47; p = 0.011 respectively. Conclusions: In our series, the occurrence of a second pelvic primary malignancy is statistically associated with the modality of radiotherapy administered and occurrence of chronic adverse effects (AU)

Analysis of the Influence of Peripheral Anatomical Changes for CBCT-Guided Prostate Cancer Radiotherapy.

PURPOSE: To analyze the influence of the bladder and rectum filling and the body contour changes on the prostate target dose. METHODS: A total of 190 cone-beam CT (CBCT) image data sets from 16 patients with prostate cancer were used in this study. Dose reconstruction was performed on the virtual CT generated by the deformable planning CT. Then, the effects of the bladder filling, rectal filling, and the patient's body contour changes of the PCTV1 (the prostate area, B1) and PCTV2 (the seminal vesicle area, B2) on the target dose were analyzed. Correlation analysis was performed for the ratio of bladder and rectal volume variation and the variation of the bladder and rectal dose. RESULTS: The mean Dice coefficients of B1, B2, bladder, and rectum were 0.979, 0.975, 0.888 and 0.827, respectively, and the mean Hausdorff distances were 0.633, 1.505, 2.075, and 1.533, respectively. With the maximum volume variations of 142.04 ml for the bladder and 40.50 ml for the rectum, the changes of V100, V95, D2, and D98 were 1.739 ± 1.762 (%), 0.066 ± 0.169 (%), 0.562 ± 0.442 (%), and 0.496 ± 0.479 (%) in PCTV1 and 1.686 ± 1.051 (%), 0.240 ± 0.215 (%), 1.123 ± 0.925 (%), and 0.924 ± 0.662 (%) in PCTV2, respectively. With a 10% increase in the volume of the bladder and rectum, the V75, V70, and V65 of rectum increased at 0.73 (%), 0.71 (%), and 1.18 (%), and the V75, V70, and V65 of bladder changed at -0.21 (%), -0.32 (%), and -0.39 (%), respectively. CONCLUSION: Significant correlations were observed between the volume variation and the dose variation of the bladder and rectum. However, when a bladder and rectal filling protocol was adopted, the target dose coverage can be effectively ensured based on CBCT guidance to correct the prostate target position.