Histologic correlates of progression-free interval and survival in ovarian clear cell adenocarcinoma

Unlike other ovarian epithelial cancers, histologic measures of differentiation of ovarian clear cell adenocarcinoma have not been found to be reliable predictors of progression-free interval and survival. Forty-two consecutively treated patients with pure ovarian clear cell adenocarcinoma were identified and all histologic materials were reviewed. The following histologic features were assessed: architectural pattern (tubular/tubulocystic, papillary, solid, and mixed), average and maximal mitotic activity per 10 high-power fields (hpf's), percentage of cells with clear cytoplasm, and nuclear grading (both Fuhrman et al.'s (Am. J. Surg. Pathol. 6, 655-663, 1982) and Christopherson et al.'s (Cancer 49, 1511-1523, 1982) methods). Surgical stage was most predictive of survival (P < 0.01) and subsequent comparisons using Cox proportional hazards modeling were adjusted for Stages III and IV. Greater than six mitotic figures per 10 hpf's predicted a poorer survival (P = 0.05) but was not predictive of progression-free interval (P = 0.28). Survival and progression-free interval in patients with tumors of mixed architectural pattern tended to be shorter than those for patients where one type did predominate, but this was not statistically significant (P = 0.06). The tubulocystic pattern was not predictive of patient outcome nor was either method of nuclear grading. Stage and average mitotic activity seem to be the best predictors of survival for patients with ovarian clear cell adnocarcinoma, while architectural pattern and nuclear grading are not as reliable.