Disclosures: Hyunwoo J. Choo, MD, MPH: No financial relationships or conflicts of interest

Objective: While pelvic floor dysfunction (PFD) is common issue amongst patients with gynecologic cancer, the impact of radiation specifically on pelvic floor muscle bulk and subsequent pelvic floor symptoms has not been previously investigated. Herein, we aimed to quantify volumetric changes in pelvic floor musculature before and after radiation therapy for endometrial cancer, and to correlate changes with pelvic floor dysfunction symptoms.

Design: Pilot retrospective cohort study

Setting: Radiation oncology department in a single academic center

Participants: 20 female patients diagnosed with non-metastatic endometrial cancer undergoing pelvic radiotherapy

Interventions: Patients receiving radiotherapy undergo pelvic CT scan prior to treatment for radiation planning, and 3-12 months following treatment for surveillance. Pelvic floor (PF) muscle volumes were obtained by contouring pre- and post-radiation scans using the radiation treatment planning software MIM. Patient’s pelvic floor symptoms were collected and quantified via chart review. Linear regression analysis between volume change and variables of interest was performed.

Main Outcome Measures: Individual (obturator internus, piriformis) and total pelvic floor muscle volume changes, PFD symptoms

Results: Volumetric analysis of the pelvic floor muscles pre- and post-radiation treatment demonstrated significant decrease in piriformis (pre=69.70 cm3, post=61.12 cm3, p < 0.01) and total pelvic muscle volume (pre=152.66 cm3, post=140.57 cm3, p < 0.01). Regression analysis demonstrated that percent change in pelvic muscle volume had a trend towards an inverse relationship with the number of pelvic floor symptoms (slope=0.36 p=0.098).

Conclusions: Using a novel approach of volumetric measurement of pelvic floor muscles before and after radiation, our data demonstrates that there is significant decrease in the muscle volume following radiotherapy that trends with increased pelvic floor symptoms. This pilot work strongly suggests that larger scale studies of pelvic floor muscle volume and function are needed. Our approach will enable the development of dosimetric dose constraints to minimize pelvic floor atrophy, and help identify patients who need rehabilitation interventions to minimize dysfunction.

Level of Evidence: Level IV

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/the-link-between-pelvic-floor-muscle-atrophy-after-radiation-for-endometrial-cancer-and-pelvic-floor-dysfunction/