ارزیابی سرطان‌های ثانویه ایجادشده در اندام‌های در معرض خطر حین پرتودرمانی سرطان پروستات: یک گزارش کوتاه

زمینه و هدف: ازآنجاکه پرتودرمانی سرطان پروستات ممکن است همراه با عوارض جانبی باشد، لذا هدف از مطالعه حاضر بررسی خطر ابتلا به سرطان‌های ثانویه پس از پرتودرمانی سرطان پروستات در اندام‌های خارج از میدان است. روش بررسی: داده‌های هیستوگرام دوز حجمی 39 بیمار مبتلا به سرطان پروستات (که توسط پرتودرمانی سه‌بعدی تطبیقی درمان شده بودند) استخراج شد و میزان دوز جذب‌شده در بافت‌های حساس موردمطالعه با توجه به مفهوم geud محاسبه شد. سپس خطر بدخیمی‌های متعاقب پرتودرمانی سرطان پروستات با استفاده از مدل معرفی‌شده در گزارش beir محاسبه شد. یافته‌ها: مقادیر geud راست‌روده بین 51.04 گری تا 74.69 گری و برای مثانه از 27.22 گری تا 75.51 گری متغیر بود. حداکثر مقادیر احتمال خطر برای راست‌روده و مثانه به‌ترتیب 49.85% و 74.91% محاسبه شد. نتیجه‌گیری: نتایج حاصل نشان دادند که احتمال بیشتری برای ایجاد بدخیمی‌های ثانویه در مثانه نسبت به راست‌روده وجود دارد.

secondary cancers evaluation inside organs at risk during the prostate cancer radiotherapy: a brief report

background: in prostate cancer radiotherapy, due to the proximity of the prostate to the rectum, it can be affected by high radiation doses. it has been reported that about 70% of secondary cancers after prostate cancer radiotherapy occur in the bladder and rectum, which are exposed to direct radiation. since prostate cancer radiotherapy may be accompanied by side effects, the aim of this study is to investigate the risk of secondary cancers after the radiotherapy of prostate cancer inside the outfield organs. methods: the dose volume histogram data relevant to 39 patients with prostate cancer (who were treated with 3-dimensional conformal radiotherapy technique in 2022 in tehran) were extracted, and the uniform absorbed dose inside the sensitive tissues was calculated according to the geud concept. then, the risks of secondary malignancies following prostate cancer radiotherapy were calculated using the model introduced by the beir report. accordingly, the lifetime attributable risk values (lar) were estimated based on the desired organs and patient age at exposure time through the calculation of excess relative risk (err) and excess absolute risk (ear) values. results: from the obtained results, the geud values for the rectum ranged from 51.04 gy to 74.69 gy and for the bladder from 27.22 gy to 75.51 gy. the maximum calculated risk values for the rectum and bladder were calculated to be 49.85% and 74.91%, respectively. besides, a significant level of secondary cancer risk within the rectum and bladder was obtained for most of the studied patients. furthermore, small values of secondary cancer risks were estimated for patients who were irradiated at older ages, and higher ones were obtained for patients who were irradiated at younger ages. conclusion: the results showed that there is a higher probability of developing secondary malignancies in the bladder than the rectum. the information obtained in this research can improve the performance of the treatment process, so that information about secondary cancers following radiation therapy for prostate cancer will ultimately help doctors design more effective and optimal treatment designs.