Advanced ovarian cancer: correlation of histologic grade with response to therapy and survival.

In order to determine the prognostic and therapeutic importance of histologic grade for patients with advanced ovarian cancer, the pathologic specimens from 82 patients with Stage III-IV disease (as defined by the International Federation of Gynecologists and Obstetricians (F.I.G.O.)) were reviewed and graded by two methods. A system based on cytologic detail using both the degree of anaplasia and the number of undifferentiated cells, (modified Broders' Grades 1--4) was found to be particularly useful because it identified four groups with different survival outcomes as well as an apparent differential response to chemotherapy. Specifically, the overall improvement of survival in patients with Stage III-IV disease observed in a prospective study of combination chemotherapy was related primarily to an increased survival of patients with Grade 2 and 3 lesions. Survival in Grade 1 patients was markedly better than for Grade 4 patients, but in neither case did survival appear to be influenced by the choice of chemotherapy. These observations suggest that prospective clinical trials assessing the efficacy of chemotherapy should employ cytologic grades as a separate stratification factor since chemotherapy for advanced disease may have to be tailored, in part, to the histologic grade.