Dosimetric Advantage of Scanning Beam Proton Therapy in Gynecologic Patients Receiving Adjuvant Radiotherapy

Authors

Rachel B Ger
Jarrod M Lentz
Joshua S Niedzielski
Sujay A Vora
Martin Bues
Danairis Hernandez Morales
Justin D Anderson
Christopher J Kutyreff
Christie A Schulz
Pedro R Lara
Ana K Ridgway
Pamela R Lemish
Justin D Gagneur
Aman Anand

Publication Date

6-17-2025

Journal

Cancers

DOI

10.3390/cancers17122010

PMID

40563662

PMCID

PMC12190590

PubMedCentral® Posted Date

6-17-2025

PubMedCentral® Full Text Version

Post-print

Abstract

Background/Objectives: Adjuvant radiation for gynecologic malignancies often exposes organs at risk (OARs), such as the bone marrow, bowel, rectum, and bladder, to radiation, leading to toxicities that impact treatment tolerance and patient quality of life. Scanning proton beam therapy, particularly with Individual Field Simultaneous Optimization (IFSO), may offer dosimetric and biological advantages over volumetric modulated arc therapy (VMAT). This study evaluates the clinical impact of IFSO-based proton planning in post-operative gynecologic cancer patients.

Materials and Methods: Fourteen patients receiving adjuvant proton therapy to 45 Gy in 25 fractions were retrospectively analyzed. Comparison VMAT plans were generated on the same datasets. Dose-volume metrics for key OARs and normal tissue complication probabilities (NTCPs) were compared using paired statistical tests. Robustness evaluations accounted for setup and range uncertainties.

Results: Proton plans significantly reduced dose to bone marrow (V10Gy: 58% vs. 86%, p < 0.00001; V20Gy: 47% vs. 58%, p < 0.00001), small bowel (V20Gy: 21% vs. 56%, p < 0.00001), and femoral heads (left femoral head mean: 11Gy vs. 13Gy, p = 0.032; right femoral head mean: 11Gy vs. 13Gy, p = 0.022). NTCP modeling predicted significantly lower rates of bowel urgency (9.4% vs. 3.3%, p < 0.001) and hematologic toxicity (10.2% vs. 4.9%, p < 0.001) with proton therapy. Plans remained robust across uncertainty scenarios.

Conclusions: IFSO-based scanning proton therapy provides clinically meaningful sparing of bone marrow and bowel, with the potential to reduce hematologic and gastrointestinal toxicities. These findings support its use in patients receiving adjuvant pelvic radiotherapy, particularly those undergoing extended field treatment or chemotherapy.

Keywords

gynecological malignancy, proton therapy, NTCP

Published Open-Access

yes

Recommended Citation

Ger, Rachel B; Lentz, Jarrod M; Niedzielski, Joshua S; et al., "Dosimetric Advantage of Scanning Beam Proton Therapy in Gynecologic Patients Receiving Adjuvant Radiotherapy" (2025). Faculty, Staff and Student Publications. 4904.
https://digitalcommons.library.tmc.edu/uthgsbs_docs/4904