3121 - Feasibility of Uterus-Sparing Pelvic Radiotherapy for Fertility Preservation in Premenopausal Women: A Dosimetric Planning Study
Presenter(s)
K. Sharma1, B. Huang2, J. Antone2, J. Chang2, C. Martucci3, B. F. Bloom2, G. Wernicke2, and B. Parashar3; 1Virgina Commonwealth University, Richmond, VA, 2Northwell Health, Lake Success, NY, 3Northwell, New Hyde Park, NY
Purpose/Objective(s): Cancer survival among women <45 years now exceeds 70–80%, shifting focus toward survivorship and fertility preservation. Pelvic radiotherapy (RT) can impair uterine integrity, increasing risks of miscarriage, preterm birth, and low birth weight. Despite this, the uterus is not routinely treated as an organ-at-risk (OAR), and no standard dose constraints exist. We evaluated the feasibility of uterus-sparing pelvic RT while maintaining adequate target coverage.
Materials/Methods: In this IRB-approved planning study, previously treated women <45 years who received pelvic RT for gynecologic or colorectal malignancies were retrospectively replanned. Original plans were recreated in Eclipse™ (Varian). The uterus and pelvic nodal volumes were contoured in addition to standard OARs. Planning objectives included nodal and target coverage (PTV D95% =95%), uterus mean dose =20 Gy, and adherence to institutional OAR constraints. VMAT-based inverse planning was used to optimize coverage while minimizing uterine dose. Dosimetric parameters were compared descriptively.
Results: Thirteen patients were replanned. Adequate target and nodal coverage (PTV D95% =95%) was achieved in all cases at a prescription dose of 45 Gy. Median uterine mean dose was 15.0 Gy (range: 11.4–34.9 Gy), meeting the predefined constraint in 92% of cases. Median uterine V10Gy and V20Gy were 8% (range: 0–60%) and 69% (range: 0–98%), respectively. Mean bladder dose was 35.2 Gy (range: 23.5–40.1 Gy), remaining within acceptable limits. The uterine constraint was not achieved in one patient with vulvar cancer due to target proximity.
Conclusion: Uterus-sparing pelvic RT using modern VMAT planning is dosimetrically feasible without compromising target coverage. Substantial reductions in uterine dose can be achieved in most patients, supporting the uterus as a modifiable OAR. These findings provide a foundation for prospective evaluation of fertility-preserving RT strategies and may inform future guideline development for young women undergoing pelvic irradiation.