The relationship among primary anatomic subsite and risk and distribution of second malignant neoplasms in patients with stage I/II diffuse large B-cell lymphoma: An analysis of the surveillance, epidemiology, and end results database

BACKGROUND: Recent studies have reported that diffuse large B-cell lymphoma (DLBCL) involving different primary extranodal sites have distinct clinicopathological characteristics and prognosis. However, the risk of secondary malignant neoplasms (SMNs) in DLBCL survivors with different primary extranodal sites are unknown. METHODS: A total of 40,714 patients diagnosed with stage I/II DLBCL were included from the Surveillance, Epidemiology, and End Results (SEER) database from 1983 to 2015.The standardized incidence ratio (SIR) and absolute excess risk (AER) were used to assess the risk of SMNs. RESULTS: The results show that the risk of SMN was significantly higher in extranodal DLBCL than in the US general population (SIR, 1.18; 95% CI, 1.11–1.26), and the risk of developing SMN remains significantly elevated with increased latency. Moreover, there were multiple site-specific risk patterns. There was a 22%, 44%, 66%, 123% and 151% increased risk of SMN 10 years after primary gastrointestinal tract, head/neck, skeletal, lung and liver/pancreas DLBCL diagnosis, respectively. There was a significant decrease risk of SMN with increasing age at diagnosis for primary gastrointestinal tract and skeletal DLBCL. In addition, DLBCL patients with primary sites in the gastrointestinal tract, thyroid and liver/pancreas had the highest incidences of secondary stomach cancer, second thyroid cancer, and second hepatobiliary cancer, respectively, which indicated that the initial site of DLBCL may predict the type of SMN. CONCLUSIONS: The strategies for cancer surveillance after extranodal DLBCL diagnosis may need to be individualized according to the subsite of extranodal DLBCL.