Kaplan–Meier ovarian cancer-specific survival showing number of women at risk according to grade of ovarian carcinosarcoma and undifferentiated carcinoma. Women with ovarian carcinosarcoma (8950/3, 8951/3 & 8980/3) that was grade 1 well differentiated (blue curve, n = 29; 50, 100 & 200-month survival is 89.1.0%, 89.1%, 81.7%), grade 2 moderately differentiated (red curve, n = 40; 50, 100 & 200-month survival is 37.7%, 31.9%, 31.9%), and grade 3 undifferentiated (green curve, n = 1250; 50, 100 & 200-month survival is 31.8%, 21.8%, 18.9%). Log-rank test p < 0.001. Women with undifferentiated EOC (8020/3) that was grade 3 by definition (black curve, n = 304; 50, 100 & 200-month survival is 46.9%, 32.9%, 25.8%).