Site-specific factors for cancer of the corpus uteri from SEER registries: collaborative stage data collection...

Uterine cancer is the fourth leading cancer among US women. Changes in uterine cancer staging were made from the American Joint Committee on Cancer (AJCC) 6th to 7th edition staging manuals, and 8 site-specific factors (SSFs) and 3 histologic schemas were introduced. Carcinomas account for 95% of cases and are the focus of this report.

Distributions of SSF values were examined for 11,601 cases of malignant cancer of the corpus uteri and uterus, NOS (not otherwise specified) diagnosed in Surveillance, Epidemiology, and End Results (SEER) Program registries during 2010. AJCC 6th and 7th edition staging distributions were compared for 11,176 cases using data in both staging systems. AJCC 6th edition staging distributions during 2004-2010 were examined. AJCC 7th edition SSFs required by SEER were International Federation of Gynecology and Obstetrics stage (SSF1), peritoneal cytology (SSF2), number of positive pelvic lymph nodes (SSF3), number of pelvic lymph nodes examined (SSF4), number of positive para-aortic lymph nodes (SSF5), and number of para-aortic lymph nodes examined (SSF6).

For SSFs related to lymph nodes, a third of cases were classified as "not applicable," reflecting that lymph node dissection is not indicated for cases with stage1A and stage 4 diagnoses. AJCC 7th edition criteria assigned more cases to stage I (72.9%) than AJCC 6th edition criteria (68.7%). Annual counts significantly increased during 2004-2010, as did counts for AJCC 6th edition stages INOS, IA, IB, IC, IIIA, IIIB, IIIC, and IVB. The proportion of cases diagnosed with stage I cancer was stable, whereas stages II and IV decreased and stage III increased.

Five SSFs were suitable for analysis: peritoneal cytology results (SSF2), numbers of positive pelvic lymph nodes (SSF3), pelvic lymph nodes examined (SSF4), positive para-aortic lymph nodes (SSF5), and para-aortic lymph nodes examined (SSF6).