Stereotactic Ablative Body Radiotherapy Boost for Cervical Cancer When Brachytherapy Boost is Not Feasible

Abstract

The purpose of this study was to analyze the treatment efficacy and safety of stereotactic ablative body radiotherapy (SABR) boost for cervical cancer patients not amenable to brachytherapy.A retrospective review of the medical records of 25 eligible patients was performed. The patients underwent pelvic radiotherapy in 25 or 28 fractions with a median dose of 45 Gy (range, 44-50.4 Gy). SABR boost was delivered after pelvic radiotherapy, with a median dose of 25 Gy (range, 20 to 33 Gy), and a median fraction number of 5 (range, 4-6). Patients with a follow-up period of more than one year were included in the toxicity analysis, and hematuria and hematochezia that occurred later than 3 months after the radiotherapy were graded.The median follow-up period after RT was 2.85 years (range, 0.33 to 6.60). The 3-year local control, locoregional control, disease-free survival, and overall survival rates were 80.9%, 75.8%, 40.9%, and 77.1%, respectively. The 3-year rates of freedom from hematuria and hematochezia were 58.5% and 29.6%, respectively. No grade 4-5 toxicity was reported. Receiver operating characteristic (ROC) curve analysis showed that simple summation of the mean biologically equivalent dose (BED) to the bladder was predictive of hematuria (P = 0.040), while the simple summation of the maximum BED to the rectum was marginally predictive of hematochezia (P = 0.057).SABR boost for cervical cancer was effective and tolerable. Although it cannot substitute brachytherapy, it can be a treatment option when brachytherapy is not possible.T. Lee: None. I. Kim: None. J. Kim: None. C. Song: None. Y. Kim: None. K. Kim: None. J. No: None. D. Suh: None. J. Chung: None. K. Eom: None.