Oophorectomy and Colon Cancer

Abstract

Data on survival and survival free-from-recurrence were analyzed retrospectively in a group of 571 women who had undergone curative resection for colon cancer at the Mayo Clinic [USA] between 1972-1978. Of these women, 75 (group 1) had required bilateral oophorectomy before or at colon resection, while 496 (group 2) retained 1 or both ovaries. Average age, location and grade of tumor, and duration of follow-up were similar for both groups. Five-year-survival rate for the 571 women was 73.6% as compared with 84.3% for matched controls. The 5-yr survival rates were not significantly different for group 1 (78.0%) and group 2 (72.9%). Five-year survival free-from-recurrence also was not significantly different (82.9%, group 1 and 79.5%, group 2). Women in group 1 who had grade 1 or 2 tumors or lesions in the sigmoid and cecum fared the best (no significant difference from controls). Incidence studies of ovarian metastases from colon cancers suggest that 3-8% of women should benefit from bilateral oophorectomy. This agrees with the difference in survival observed between groups 1 and 2 in this study. Sample size is too small to statistically confirm the reliability of this difference. The design of a prospective study testing this hypothesis is outlined.