Serous surface papillary carcinoma (SSPC) is a multicentric peritoneal tumor that can spare or minimally involve the ovaries and has been reported to be more aggressive than the usual form of serous carcinoma of the ovary (SCO). From 360 serious ovarian carcinomas, we selected 87 cases with high histological grade, clinical stage III, residual disease after the first operation, similar chemotherapeutic regimens, and at least a 4-year follow-up period. Of these, 33 patients had SSPC in which the tumors were smaller than 10 mm (ovaries not enlarged), and 54 had SCO in which the tumors were larger than 5.0 cm. The 33 cases with SSPC were then subdivided according to tumor size: (a) 17 patients had SSPC characterized by tumors that were smaller than 5.0 mm in largest dimension and that involved only the ovarian surface or showed minimal superficial invasion of the ovarian cortex (maximum depth, 3 mm); (b) 16 patients had SSPC characterized by tumors that measured 5.1 to 10 mm and involved the ovarian surface, cortex, and/or medulla. The subdivision of the SSPC into small and large types was found to be of no clinical statistical significance; thus, the two groups were recombined as a single group. The difference in length of survival between SSPC and SCO at 24 months (39% versus 32%, respectively) and the median survival times (SSPC = 17 months and SCO = 18 months) were not statistically significant. However, the 48-month survival rate (SSPC = 28% and SCO = 9%), was statistically significant (p = 0.027).(ABSTRACT TRUNCATED AT 250 WORDS)