[1220] A Clinicopathologic Analysis of 419 Consecutive Endometrial Carcinomas with Emphasis on Lower Uterine Segment Tumors
Saul L Offman, Sofia Liou, Anne M Mills, Teri A Longacre. Stanford University, Stanford, CA
Background: The clinicopathological features of lower uterine segment (LUS) endometrial carcinomas are incompletely defined.
Design: 419 consecutive cases of primary endometrial cancer were stratified by site of tumor involvement (LUS vs corpus vs LUS and corpus) and evaluated for patient age at time of presentation, tumor type, grade, stage, and mismatch repair protein status. Real-time PCR (Methylight) DNA methylation analysis was performed in cases with MLH1/PMS2 deficiency.
Results: Patients with LUS only tumors were younger than those with corpus only tumors (p=0.0004) or tumors involving the corpus and LUS (p=0.001). The proportion of non-endometrioid tumors tended to be increased in the LUS compared to the corpus, but only the proportion of undifferentiated carcinoma reached statistical significance (7.7% in LUS vs. 0.6% in corpus; p=0.03). The proportion of Lynch syndrome (LS)-associated cancer in the LUS was higher than in the corpus, but this did not meet statistical significance.
| LUS | Corpus | LUS and Corpus | |
|---|---|---|---|
| Cases | 26 (6.2%) | 312 (74.5%) | 81 (19.3%) |
| Age (yr) | 55.4 +/- 15.3 | 64.2 +/- 11.8 | 65.8 +/- 13.3 |
| Non-Endometrioid | 34.6% | 19.6% | 19.8% |
| Grade 3 | 46.2% | 31.1% | 43.2% |
| Stage III/IV | 23.1% | 19.6% | 35.8% |
| dMMR | 30.4% | 29.6% | 28.4% |
| LS-associated | 13.0% | 7.7% | 5.4% |