Postoperative low-pelvic irradiation for stage I-IIA cervical cancer patients with risk factors other than pelvic lymph node metastasis.

PURPOSE: To retrospectively investigate whether postoperative low-pelvic radiotherapy (RT) is an appropriate treatment for node-negative, high-risk Stage I-IIA cervical cancer patients. METHODS AND MATERIALS: A total of 228 Stage I-IIA cervical cancer patients treated by radical surgery and postoperative RT were included in this study. All patients had histopathologically negative pelvic node metastasis, but at least one of the following risk factors: parametrial involvement, positive or close resection margins, invasion depth two-thirds or greater cervical stromal thickness. Seventy-nine patients (35%) received 30-50 Gy (median 44) to whole pelvis and a boost dose to the low pelvis (whole-pelvic RT group); the other 149 patients (65%) received low-pelvic RT only (low-pelvic RT group). For both groups, the total external RT dose to the low pelvis ranged from 40 to 60 Gy (median 50). The potential factors associated with survival, small bowel (gastrointestinal) complications, and leg lymphedema were analyzed, and patients who had a relapse in the upper pelvis were identified.
RESULTS: The 5-year overall and disease-specific survival rate was 84% and 86%, respectively. After multivariate analysis, only bulky tumor (>or=4 cm) and non-squamous cell carcinoma were significantly associated with survival. Parametrial involvement, lymph-vascular invasion, <or=50.4 Gy to the low pelvis, positive or close margins, and low-pelvic RT alone did not significantly affect survival. Grade I-V small bowel complications occurred in 33 patients (15%). Whole pelvic RT and >50.4 Gy to the low pelvis, but not old age and treatment technique (AP-PA vs. box), were significantly associated with gastrointestinal complications. Three patients (2%) in the low-pelvic RT group and 6 patients (8%) in the whole-pelvic RT group were found to have Grade III or higher small bowel complications (p = 0.023). Thirty-one percent of patients developed lymphedema of the leg. A dose to the low pelvis >50.4 Gy and an AP-PA field, but not whole-pelvic RT, old age, or the number of sampled lymph nodes, were associated with lymphedema of the leg. Five patients (3.6%) of the low-pelvic RT group and none of the whole-pelvic RT group developed upper pelvis relapse. Three of these 5 patients had upper pelvic relapse alone.
CONCLUSION: Compared with whole-pelvic RT plus low-pelvic boost, low-pelvic RT alone significantly reduces the small bowel complications in node-negative, high-risk, Stage I-IIA cervical cancer patients. Although low-pelvic RT alone increases the incidence of upper pelvic relapse, its effect on survival is not substantial. Low-pelvic RT alone appears to be an appropriate treatment method for this group of patients.