Metachronous Double Primary Cancer after Diagnosis of Gastric Cancer

PURPOSE: The pattern of double primary cancers after treatment for gastric cancer is important for a patient's survival. MATERIALS AND METHODS: We analyzed the clinicopathologic data of 214 gastric cancer patients from October 1996 to November 2007 with regard to metachronous second primary cancers. RESULTS: Out of 5,778 patients with gastric cancer, metachronous second primary cancers occurred in 214 patients. The median age was 61.8 years, the number of male and female patients was 140 (65.4%), 74 (34.6%), respectively. The median time to the occurrence of second cancers after diagnosis of the first was 39.2 months (standard deviation, 31.2 months). The most common cancer was colorectal cancer, which occurred in 44 patients (20.6%), and lung cancer in 33 patients (15.4%), hepatocellular carcinoma in 26 patients (12.1%), ovarian cancer in 15 patients (7.0%), cervical cancer in 12 patients (7.0%), breast cancer in 11 patients (5.1%), and esophageal cancer in 11 patients (5.1%). The observed/expected (O/E) ratio showed a significant increase in colorectal (1.25), male biliary (1.60), ovarian (8.72), and cervical cancer (3.33) with primary gastric cancer. After five years from diagnosis of gastric cancer, secondary cancer occurred in 50 patients (23.4%), and breast cancer, prostate cancer, laryngeal cancer, lung cancer, and hepatocellular carcinoma were the most frequent. CONCLUSION: The O/E ratio showed a significant increase in colorectal, male biliary, ovarian, and cervical cancer with primary gastric cancer, and second primary cancer as the main cause of death for these patients. A follow-up examination for metachronous double primary cancer is needed in order to improve the survival time in patients with gastric cancer.