Uterine papillary serous, clear cell, and poorly differentiated endometrioid carcinomas: a comparative study.

Introduction: Uterine papillary serous and clear cell carcinomas (UPSCs/CCs) show a different spreading from that of poorly differentiated endometrioid carcinomas (PDECs) and are usually thought to be prognostically more aggressive than PDECs. On the contrary, it has been recently claimed that UPSC/CC and PDEC have a similar prognosis. In this retrospective study on 2 institutional databases, the surgical-pathological data and survival have been compared in patients with UPSC/CC and PDEC.

Methods: A total of 139 surgically staged consecutive patients, 63 with UPSC/CC (37 UPSC; 26 CC) and 76 with PDEC clinically limited to the uterine corpus, have been compared for nuclear ploidy, myometrial invasion, (occult) cervical extension, peritoneal, and lymph node metastasis. Prognostic factors have been correlated through multivariate analysis with survival (disease-specific [DSS] and disease-free [DFS]).

Results: Peritoneal metastases and aneuploidy were found to be the only parameters significantly different in the 2 groups: peritoneal metastases 28.6% in UPSC/CC (extrapelvic 19%) and 7.9% in PDEC (extrapelvic 2.6%) (P = 0.001), aneuploidy 48.6% in UPSC/CC and 30.6% in PDEC (P = 0.05). Five-year DSS was 57.9% versus 75.2% (P = 0.02), and DFS was 52.3% versus 71.4% (P = 0.04) for UPSC/CC and PDEC, respectively. All but cervical and lymph node involvement were significant predictors of survival. After multivariate analysis, histotype (DSS: hazard ratio [HR], 1.98; 95% confidence interval [CI], 1.02-3.86; P = 0.04; DFS: HR, 1.94; 95% CI, 1.04-3.63; P = 0.04), stage (DSS: HR, 2.26; 95% CI, 1.10-4.65; P = 0.03; DFS: HR, 2.21; 95% CI, 1.12-4.38; P = 0.02), and myometrial invasion (DSS: HR, 2.86; 95% CI, 1.22-6.69; P = 0.01; DFS: HR, 3.96; 95% CI, 1.63-9.62; P = 0.002) were independent risk factors for survival.

Conclusions: Uterine papillary serous and clear cell carcinomas spread to abdominal peritoneum more frequently than PDEC; multivariate analysis confirms UPSC/CC as an independent, unfavorable predictor of outcome.