Particle Beam Radiotherapy for Gynecologic Cancers: A Scoping Review and Expert Opinion by the Particle Therapy...

To characterize the current clinical applications of particle therapy in gynecologic oncology, the Particle Therapy Cooperative Group (PTCOG) Gynecologic Subcommittee conducted a scoping review to systematically assess the available evidence and define the evolving role of particle-beam radiotherapy across gynecologic cancer subtypes.

A systematic literature search was performed in MEDLINE, Embase, Web of Science, and the Cochrane Library in accordance with PRISMA-ScR guidelines. Study selection followed a PICOS framework and was conducted in two sequential screening phases. Methodologic quality of the included studies was assessed with the Joanna Briggs Institute critical appraisal tool for case series.

Of 414 unique records identified, 41 were included in the final analysis. Publication years ranged from 1976 to 2025, with most studies (63.4%) published between 2018 and 2025, most (63.4%)from Japanese particle therapy centers, and most (n=27, 65.8%) were cohort studies or case series, including retrospective, prospective, and pair-matched cohorts, pooled analyses, and case series. Phase I and/or II clinical trials accounted for 29.3% of the studies (n=12). Carbon-ion radiotherapy was the most commonly used modality, primarily for radical treatment of radioresistant gynecologic tumors, including melanomas and locally advanced cervical cancer. Emerging data suggest a potential role for ablative particle therapy in oligometastatic ovarian disease not suitable for conventional treatments. Proton beam radiotherapy was predominantly applied in the postoperative and recurrent disease settings.

Current evidence supports the use of carbon-ion radiotherapy for the radical management of radioresistant gynecologic malignancies and unresectable recurrences. Increasing evidence also supports proton therapy, particularly as adjuvant and reirradiation therapy, to reduce toxicity and improve quality of life. Standardization of treatment protocols, centralization of rare gynecologic cancer management within the PTCOG network, and adequately powered prospective studies are needed to optimize patient selection and refine clinical indications.