Stereotactic body radiotherapy for pelvic boost in gynecological cancer patients with local recurrence or unsuitable for intracavitary brachytherapy

Objective: To evaluate efficacy of stereotactic body radiotherapy (SBRT) for pelvic boost irradiation in gynecological cancer patients with pelvic recurrence or with intact uterus unsuitable for brachytherapy. Materials and methods: We retrospectively reviewed the medical records of 25 gynecological cancer patients who received SBRT boost for pelvic recurrence (salvage group, n = 14), or for local dose escalation instead of intracavitary brachytherapy due to unfavorable medical condition (definitive group, n = 11). The pelvis was irradiated with a median dose of 54 Gy in six weeks, and then SBRT was prescribed with a range of 10-25Gy in two to five fractions. The cumulative radiobiological equivalent dose in 2-Gy fractions (EQD2) to the tumors ranged from 62.5 to 89.5 Gy(10) (median, 80.7). Overall survival (OS) and in-field relapse-free survival (IFRFS) were calculated using the Kaplan-Meier method. Results: At the initial assessment, eighteen (72%) patients achieved complete or partial remission, and seven (28%) had stable or progressive disease. With a median follow duration of 12 months, the 1-year IFRFS for salvage and definitive group were 64.5% and 90.0%, whereas the 1-year OS for the two groups were 80.8% and 49.1%, respectively. One patient developed entero-vaginal fistula and one had sigmoid perforation. No patient experienced >= grade 3 genitourinary complications. Conclusion: In gynecological cancer patients with recurrent pelvic tumors or intact uterus unsuitable for brachytherapy, local dose escalation with SBRT resulted in an initial response rate of 72% with acceptable early toxicities. A long-term follow-up is required to assess the impact on local control or survival. (C) 2021 Taiwan Association of Obstetrics & Gynecology. Publishing services by Elsevier B.V.