Adjuvant Small Pelvic Radiation Therapy in Cervical Cancer Patients With Minor Risk Factors

Abstract

To retrospectively evaluate the efficacy of adjuvant small pelvic radiation therapy (RT) in cervical cancer patients with minor risk factors after radical surgery. Seventy-six patients with at least 2 minor risk factors (tumor size > 4cm, lymphovascular space invasion (LVSI), deep stromal invasion (DSI) and adenocarcinoma histology) after surgery were treated with small pelvic RT from January 2001 through April 2013 in our department. None of the patients received concomitant chemotherapy. Median age was 54 years (range, 34-70 years). Surgery was in the form of type 3 in 72 (95%) and type 2 radical hysterectomy in 4 (5%) patients. The mean number of dissected lymph nodes (LN) was 47 (13-120). Vaginal surgical margin was positive in 4 patients (5%) and closer than 0.5cm margin in 4 (5%) patients; in addition, carcinoma in situ was detected on the surgical margin in 3 patients (3.9%). From 2001 through 2007, pelvic RT was administered as 2-dimensional RT with field borders between L5-S1 in superior, below obturator foramens in inferior and bony pelvis in lateral directions. After 2007, pelvic RT was in the form of 3-dimensional conformal RT, and the clinical target volume included primary tumor bed, proximal vagina, parametrial bed, and presacral lymphatic region as defined by RTOG. External RT was performed to small pelvis, which comprised surgical bed and presacral LNs. The median fraction dose was 1.8 Gy (range, 1.8-2 Gy), and the median total dose was 50.4 Gy (range, 45-50.4 Gy). In 9 (12%) patients with surgical margin positivity or close surgical margins, a total median dose of 21 Gy (range, 15-28 Gy) of additional brachytherapy (BRT) was also performed with median 7 Gy (range, 5-7 Gy) fraction doses. Median follow-up time was 78 months (range, 4-169 months). Local recurrence, regional recurrence or distant metastasis developed in 6 (7.9%), 3 (3.9%), and 4 (5%) patients, respectively. Median local recurrence-free survival (LRFS) was 76 months (range, 4-169 months), regional recurrence-free survival (RRFS) was 76 months (range, 4-169 months), and distant metastasis-free survival (DMFS) was 78 months (range, 4-169 months). Five-year cancer specific survival (CSS) rate was 94%; disease-free survival (DFS) rate was 86%; LRFS rate was 92%; RRFS rate was 96%; DMFS rate was 94%, respectively. In multivariate analysis, no statistically significant factor was found for CSS and DFS; however, the presence of LVSI was found significant for LRFS (P=.017). Following RT, rectovaginal fistula in 1 patient after 5 months, enterovesical fistula in 1 patient after 35 months, and rectovesical fistula in 1 patient after 40 months were observed. Our results confirmed us that small pelvic RT in patients with minor risk factors after definitive surgery is highly effective treatment strategy with high local and regional control, and DFS rates with low toxicity profile.