The characteristics and survival of second primary lung cancer after Hodgkin’s lymphoma: A comparison with first primary lung cancer using the SEER database

OBJECTIVE: The study aimed to compare the characteristics and prognosis between patients with second primary lung cancer following Hodgkin’s lymphoma and those with primary lung cancer. MATERIALS AND METHODS: Using the SEER 18 database, the characteristics and prognosis were compared between the second primary non-small cell lung cancer following Hodgkin’s lymphoma (HL-NSCLC) (n = 466) and the first primary non-small cell lung cancer (n = 469,851)(NSCLC-1), as well as between the second primary small cell lung cancer following Hodgkin’s lymphoma (n = 93) (HL-SCLC) and the first primary small cell lung cancer (n = 94,168) (SCLC-1). Comparisons of categorical variables were performed using Chi-square or Fisher’s test. Continuous variables were compared using the Mann-Whitney U test. Overall survival (OS) was estimated using the Kaplan-Meier method, and the difference between groups was analyzed by log-rank test. RESULTS: HL-NSCLC group had more males than NSCLC-1 group, and the median age of HL-NSCLC group was younger than that of NSCLC-1 group. Patients with HL-NSCLC showed inferior OS than those with NSCLC-1 (median: 10 months vs. 11 months, P = 0.006). Both HL-SCLC and SCLC-1 groups had poor prognosis, with median OS of 7 months (P = 0.4). The 3-year cumulative risks of death from any cause for patients with the latencies from HL to NSCLC of 0 to 5 years, >5 to 10 years, >10 to 15 years, >15 to 20 years, and>20 years were 71.8%, 82.6%, 86.8%, 85.7% and 78.5%, respectively(P = 0.020). CONCLUSION: HL-NSCLC patients had worse prognosis than NSCLC-1 patients, while HL-SCLC patients shared similar characteristics and survival with SCLC-1 patients.