[Clinicopathological study of SET subtype of ovarian high-grade serous carcinoma]

Objective: To investigate the clinicopathological characteristics and significance of solid, endometrioid and transitional (SET) ovarian high-grade serous carcinoma (HGSC). Methods: A total of 408 cases of ovarian HGSC admitted to Peking University People's Hospital from January 2011 to September 2016 were collected. (1) According to the proportion of tumors with SET form in all tumors, they were divided into three groups: HGSC-classic group (<25%), HGSC-SET Ⅰ (25%-50%) and HGSC-SET Ⅱ (>50%) group. The clinical and pathological characteristics of three groups of ovarian HGSC patients were compared respectively. (2) According to the growth pattern, that was, the proportion of pushing/expanding invasive tumors in the whole pelvic disseminated tumors of pelvic disseminated tumors, the three groups were divided into four subgroups: group A (0-25%), group B (26%-50%), group C (51%-75%) and group D (>75%). Differences in progression-free survival (PFS) among the four subgroups in each group were compared respectively. Results: The median age of 408 cases with ovarian HGSC was 63.3 years (47-78 years), including 152 cases premenopausal and 256 cases postmenopausal. Among 408 cases of ovarian HGSC, 290 cases were in HGSC-classic group, 91 cases in HGSC-SET Ⅰ and 27 cases in HGSC-SET Ⅱ group. (1) There were significant differences in age, proportion of menopausal patients, tumor necrosis (including map necrosis or acne necrosis), response rate to primary chemotherapy, 5-year mortality rate and PFS between HGSC-SET Ⅰ and HGSC-SET Ⅱ (P<0.05). There was no significant difference among the above indexes between HGSC-SET Ⅰ and HGSC-SET Ⅱ (P>0.05). In HGSC-classic group, HGSC-SET Ⅰ and HGSC-SET Ⅱ, the proportion of family members or patients with history of epithelial ovarian cancer or breast cancer increased in turn, and the detection rate of serous tutal intraepithelial carcinoma (STIC) in fallopian tube tissue decreased in turn. There were significant differences between the two groups (P<0.05). (2) In HGSC-classic group, there were 147 cases in group A, 124 cases in group B and 19 cases in group C (0 case in group D), with median PFS of 17.4, 17.7 and 16.5 months respectively (P<0.05); 10, 6, 29 and 46 cases in group A, B, C and D in HGSC-SET Ⅰ, with median PFS of 9.6, 12.7, 30.1 months and 39.0 months respectively, which there were significant difference among group A and C and D (all P<0.05); among group B, C and D group in HGSC-SET Ⅱ, there were respectively 3, 12 and 12 cases (0 case in group A), and the median PFS was 13.5, 34.2 and 47.8 months (P<0.05). PFS was positively correlated with the increase of push/expansive infiltration ratio. Conclusions: The detection rate of STIC in ovarian HGSC patients with SET is higher, the effect of primary chemotherapy is better, and PFS is prolonged. PFS was significantly prolonged in patients with pelvic disseminated tumors of HGSC-SET, the infiltration of which were predominated by pushing or expanding boarder.