Ovarian Transposition Before Pelvic Radiation Therapy: Spatial Distribution and Dose Volume Analysis

Area of Science:

• Reproductive medicine
• Radiation oncology
• Gynecologic oncology

Background:

• Pelvic radiation therapy (RT) poses a risk to ovarian function.
• Ovarian transposition is a technique to preserve fertility and hormonal function.
• Data on the precise location and radiation dose to transposed ovaries is limited.

Purpose of the Study:

• To analyze the anatomic locations and radiation dose metrics of surgically transposed ovaries in patients receiving pelvic RT.
• To evaluate the effectiveness of ovarian transposition in shielding ovaries from RT.
• To inform surgical and RT planning for improved ovarian preservation.

Main Methods:

• Retrospective analysis of women undergoing ovarian transposition before pelvic RT (2010-2020).
• Measurement of ovarian position relative to sacral promontory, iliac crest, and RT planning target volume (PTV).
• Calculation of radiation dose (mean and maximum) to transposed ovaries.

Main Results:

• Thirty-one ovaries from 18 patients were analyzed.
• Most ovaries (64.5%) were located outside the PTV and above the sacral promontory.
• Despite being outside the PTV, median ovarian doses were 15.5 Gy (mean) and 32.2 Gy (maximum), associated with high failure risk.
• Distance from the iliac crest was a significant predictor of ovary location outside the PTV.

Conclusions:

• Transposed ovaries often receive high radiation doses, increasing the risk of ovarian failure.
• Current transposition techniques may not sufficiently shield ovaries from pelvic RT.
• More aggressive ovary-sparing strategies are necessary to improve fertility and hormonal preservation outcomes.