Mean Rectal Radiation Dose in Clinically Localized Prostate Cancer Treated with Moderate Hypofractionated Radiotherapy

Background: Globally, prostate cancer is among the most common cancers affecting men. While external beam radiation therapy (EBRT) is essential for its management, radiation exposure to adjacent organs, including the rectum, may lead to gastrointestinal toxicity. This study aimed to ascertain the average radiation dose to the rectum in patients with moderately hypo-fractionated radiation therapy for clinically localized prostate cancer. Methods: Between June and August of 2025, a retrospective cross-sectional study was carried out at the INMOL Hospital's Department of Radiotherapy in Lahore. There were 55 male patients with histologically confirmed localized prostate adenocarcinoma (T1c–T3a N0 M0) who were between the ages of 40 and 80. All were given 60 Gray (Gy) in 20 fractions (3 Gy per fraction) via Intensity-Modulated Radiation Therapy (IMRT). The dose-volume histograms (DVHs) were used to extract the rectal dosimetric parameters. Chi-square and t-tests were used (p-value<0.05) via SPSS v26.0. Results: The patients were primarily elderly, with a mean age of 68.4 ± 8.7 years. Within the recommended tolerance limits, the average rectal dose was 29.2 ± 3.6 Gy, indicating consistent treatment delivery. The correlation between age and mean rectal dose was weak and statistically non-significant (r = 0.18, p = 0.12), but there was a significant relationship between tumor grade and clinical stage (χ² = 9.12, p = 0.037, Cramer's V = 0.29). Conclusion: Consistent rectal dose limitation was accomplished by moderately hypo-fractionated IMRT without reducing disease coverage.