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

ObjectiveThe 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 methodsUsing 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. ResultsHL-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). ConclusionHL-NSCLC patients had worse prognosis than NSCLC-1 patients, while HL-SCLC patients shared similar characteristics and survival with SCLC-1 patients.