Use of the small pelvic field instead of the classic whole pelvic field in postoperative radiotherapy for cervical cancer: reduction of adverse events.

PURPOSE: We examined whether use of small pelvic (SP) field encompassing only the pericervical regions and upper stream lymphatic will reduce the adverse events that occur with classic whole pelvic (WP) field, in postoperative radiotherapy (RT) for cervical cancer. METHODS AND MATERIAL: This retrospective study included 72 patients treated with SP field (SP group) used specifically for node-negative status and 46 patients treated with WP field (WP group) used conventionally for node-positive status. Total dose was 50.0 or 50.4 Gy at 2.0 or 1.8 Gy per fraction. Acute adverse events (nausea, diarrhea, cystitis, and leukopenia) and late adverse events (lymphedema, cystitis, ileus, and diarrhea) were graded according to the Common Toxicity Criteria and compared between groups.
RESULTS: Diarrhea (Grades 2-3) and leukopenia (Grades 1-3) occurred significantly more often in WP group (32.4% and 80.5%, respectively) than in SP group (9.2% and 52.2%, respectively). Among the late events, lymphedema occurred most often overall (5-year rate: SP, 47.0%; WP, 49.1%). Only ileus occurred at a significantly higher rate in The WP group than in SP group (5-year rate: 16.2% vs. 3.2%).
CONCLUSIONS: Use of the SP field tailored for node-negative status was suggested to reduce adverse events involving the intestine and hemopoietic system.