Clinical Analysis of 152 Cases of Multiple Primary Malignant Tumors in 15,398 Patients with Malignant Tumors

OBJECTIVES: In this study, the etiology, clinical characteristics, and prognosis of multiple primary malignant tumors (MPMTs) were investigated. Furthermore, we analyzed the treatment factors associated with MPMTs. METHODS: From 15,398 patients with malignant tumors presenting to The First Hospital of Jilin University, China, between January 2010 and December 2013, we identified and analyzed patients with MPMTs. Data were obtained retrospectively from the hospital database. RESULTS: The prevalence of MPMTs in this study was 0.99% (152/15398): 51 cases were synchronous MPMTs, and 101 cases were metachronous MPMTs. The mean time between the first and second primary cancer was 43.1 months. In this population, MPMTs were observed more frequently in patients with head and neck tumors (5.65%) and urinary tumors (4.19%); the prevalence of MPMTs in these patients was over 4-fold greater than the prevalence of MPMTs in all patients (0.99%). There were no cases of MPMTs in 132 cases of nervous system tumors and 404 cases of multiple myeloma. Nearly 50% (45.4%) of patients with MPMTs did not receive chemotherapy or radiotherapy before the second primary cancer was diagnosed. Eighty-five patients with MPMTs were followed for more than 2 years, and the 2-year cumulative survival rate was 40.8%. CONCLUSIONS: In this study, the prevalence of MPMTs was 0.99% (152/15398), which is consistent with the Chinese literature. Patients with head and neck tumors or urinary tumors are at greater risk of developing MPMTs. In addition to radiotherapy or chemotherapy, this study suggests that other factors may contribute to MPMTs.