The Value of Boost to Vaginal Cuff with External Beam Radiation Therapy (EBRT) for Cervical Cancer Patients with High/Moderate Risk Factors after Radical Hysterectomy

Abstract

In early stage cervical cancer, adjuvant radiotherapy following radical hysterectomy has been recommended in patients who are considered to at high or moderate risk for recurrence. Brachytherapy may be used as a boost to external beam radiation therapy (EBRT). With the rapid development of recent EBRT techniques, a radiation boost to the vaginal cuff and parametria can be achieved by EBRT techniques. Several years ago we reported very good oncologic outcomes and low toxicity of the simultaneous integrated boost (SIB) or late course accelerated boost (LCAB) with external beam radiotherapy (EBRT) to the vaginal cuff for high or moderate risk cervical cancer patients after radical hysterectomy. Here we report further results of EBRT boost and make the comparison with non-boost data. Between October 2009 and January 2015, cervical cancer patients with high or moderate risk who had undergone radical hysterectomy (R0 resection) followed by EBRT were enrolled. Patients were treated with pelvic intensity modulated radiotherapy (IMRT)/volumetric modulated arc therapy (VMAT) with or without boost to vaginal cuff. Boost were conducted by either SIB (arm A) or LCAB (arm B). In arm A, the pelvic and boost doses were 50.4 Gy and 60.2 Gy in 28 fractions, respectively. In arm B, pelvic irradiation to 50 Gy in 25 fractions followed by a boost of 9 Gy in 3 fractions were delivered. Some patients with moderate risk only received EBRT without boost (arm C). platinum-based adjuvant chemotherapy was given concurrently. Overall, 265 patients were retrospectively analyzed in this study (81 in high risk group R-H and median follow-up 37 months, 184 in moderate risk group R-M and median follow-up 41 months). The 5-year disease-free survival（DFS）and overall survival（OS）in groups R-H vs R-M were 83.3% vs 83.4% and 85.7% vs 93.7% (p= 0.045), respectively. Patients in the high risk group had all undergone radiation boost to the vaginal cuff and parametria. The 5-year DFS and OS in arm A (SIB) vs B (LCAB) were 91.7% vs 95.5% (p=0.363), and 83% vs 89.6% (p=0.358), respectively. Patients in the moderate risk group were treated with the EBRT boost to vaginal cuff (arm boost) or not (arm C). The 5-year DFS and OS in arm boost vs arm C were 86.4% vs 79.3% (p=0.62), and 93.7% vs 93.5% (p=0.98), respectively. Grade 3-4 leukopenia and dermatitis were seen in 13 (16%) and 8 (9.8%) patients in R-H, vs 34 (18.5%) and 15 (8.2%) in R-M, respectively (p>0.05). Only grade 1-2 chronic gastrointestinal (GI) and genitourinary (GU) toxicities were observed. Our results indicate that cervical cancer patients with high risk after radical hysterectomy have worse prognosis than moderate risk patients. Both SIB and LCAB to vaginal cuff for the patients with high risk (R0 resection) are associated with excellent survival and low toxicity. However, EBRT boost to vaginal cuff seem to can't bring survival benefits for those patients with moderate risk after radical surgery.