Gonad Dose Assessment of Patients Undergoing Pelvic Radiotherapy

Introduction: Radiotherapy can impact on patients’ reproductive organs and fertility. This study aims (i) to assess whether the doses to the gonads of 70 patients met the tolerance doses used in radiotherapy planning; (ii) to compare Three-Dimensional Conformal Radiotherapy (3DCRT) with Volumetric Modulated Arc Therapy (VMAT) techniques; and (iii) to verify if ovarian transposition reduces the dose to the ovaries. Methods: A retrospective analysis of 70 patients aged 45 or under who underwent pelvic radiotherapy between 2014 and 2023 in a radiotherapy department was carried out. The dose constraints considered were derived from the Dose-Volume Constraints for Organs at Risk in Radiotherapy project. Results: The average number of children of all the patients in the study was 1.25 and the standard deviation was 1.40. No statistically significant differences were detected regarding the doses to the left and right gonads between 3DCRT and VMAT (p > 0.05). There were statistically significant differences between female patients who underwent ovarian transposition and those who did not undergo ovarian transposition regarding the maximum and medium doses in both right and left ovaries (p < 0.05), with a dose reduction that could reduce doses by an average of up to 39 Gy. Conclusions: In the total sample, 58.6% of patients were treated with VMAT, only 18.6% met the maximum dose limits, and 22.9% met the average dose constraints. Only five women underwent ovarian transposition, which proved effective in meeting dose constraints and significantly reducing the dose to the ovaries.