Risk of multiple primary tumors in breast cancer survivors

This study aimed to investigate the risk factors associated with subsequent multiple primary tumors in female breast cancer survivors by using analytical method for recurrent data. A total of 389,344 patients with primary breast cancer were enrolled from the SEER (Surveillance, Epidemiology, and End Results) database. The outcome of this study was the diagnosis of multiple primary tumors. SEER rules were used to define the multiple primary tumors. The comparison between the data of each group was performed by chi 2 test. Risk factors of multiple primary tumors were examined by marginal means and rates model. A total of 42020 (10.79%) patients developed multiple primary cancers, of which the majority of patients (38,767, 92.3%) with second primary tumor. There were 3013 cases and 240 cases of third primary tumor and fourth primary tumor, respectively. Older age, black race, large tumor size (> 2 cm), negative HR, mixed initial tumor histology, poor differentiated or differentiated cancer cells, and lumpectomy were associated with higher risk of subsequent multiple primary tumors. More active clinical monitoring and follow-up should be performed on breast cancer survivors who are at higher risk of multiple primary tumors, thereby improving their prognosis and life quality.