Adjuvant small field pelvic radiation for patients with high risk, stage IB lymph node negative cervix carcinoma after radical hysterectomy and pelvic lymph node dissection. A pilot study.

BACKGROUND: After radical hysterectomy and pelvic lymph node dissection, an identifiable subgroup of patients with International Federation of Gynecology and Obstetrics Stage IB lymph node negative cervix carcinoma remains at high risk of pelvic recurrence. This study attempted to determine whether postoperative small field of pelvic radiation can improve the disease free survival (DFS) of this high risk group of patients without producing significant morbidity. METHODS: Between 1991 and 1995, after radical surgery, 25 patients with Stage IB lymph node negative cervix carcinoma were considered to be at high risk of pelvic recurrence on the basis of tumor dimension, depth of stromal invasion, and the presence of lymph-vascular space invasion. All had a score >/= 120 as determined by the Gynecologic Oncology Group (GOG) study. These patients received 50.4 gray of adjuvant radiation to a small central pelvic field and were followed prospectively. A Kaplan-Meier 5-year DFS curve was generated. A log rank analysis produced an estimated log rank P value (est P value) by comparing the 5-year DFS of the patients in the current study with the 5-year DFS of the corresponding high risk group of the GOG study (observation only). The morbidity of small field pelvic radiation was recorded. RESULTS: Among the 25 patients who received small field pelvic radiation, the mean GOG score was 166 (range, 120-263) and the mean follow-up was 32 months (range, 12-64 months). There was 1 recurrence (4%) recorded at 16 months. The log rank analysis demonstrated a significant improvement in the 5-year DFS for the group who received adjuvant small field pelvic radiation (est P value = 0.005) when compared with the DFS of the high risk GOG patients who were observed postoperatively. Four cases of minor morbidity were recorded: lymphedema (three cases) and mild rectal incontinence (one case). No major morbidity was reported. CONCLUSIONS: With low morbidity, adjuvant small field pelvic radiation appears to improve significantly the 5-year DFS of patients with high risk, lymph node negative Stage IB cervical carcinoma. However, this pilot study requires verification