Synchronous and metachronous malignancy in endometrial cancer patients treated in a tertiary care center of Thailand

OBJECTIVE: To evaluate the prevalence and features of non-endometrial cancers in Thai endometrial cancer (EC) patients. METHODS: EC patients treated in our institution were identified and the following data were collected: age, EC stage, histopathology, adjuvant therapy, other cancers, living status, and cause of death. RESULTS: The mean age of the 344 patients was 56.8±10.8 years. Fifty (14.5%) had other synchronous and metachronous cancers. Mean ages of the patients with or without other cancers were not significantly different, 55.7±10.04 years versus 57.1±11.0 years, respectively (p=0.358). History of any cancer in the family and tumor in the lower uterine segment were more frequent among the patients with other cancers (6.0% vs. 1.7%, p=0.095; 12.0% vs. 1.0%, p<0.001; respectively). Six patients had ≥2 other cancers. Ovarian, breast, and colon were the three most common other cancers. After a median follow-up of 57.1 months, 18.3% of patients had died: 30.0% of patients with other cancers and 16.3% of those without other cancers. The corresponding EC deaths were 14.0% and 11.2%. The 5-year overall survival was significantly lower in patients who had other cancers: 79.3% (95% confidence interval [CI], 68.3 to 90.3) vs. 86.0% (95% CI, 81.7 to 90.3) than in those without (p=0.023). However, the corresponding disease-specific survival was not significantly different: 85.1% (95% CI, 75.5 to 94.7) compared with 89.0% (95% CI, 85.1 to 92.9), respectively (p=0.514). CONCLUSION: Thai EC patients had a high incidence of other cancers. Overall survival of EC patients who had other cancers was worse than those without, while disease-specific survival was not significantly different.