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 (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.