Prognostic impact of secondary malignancies in non-small cell lung cancer (NSCLC)

Introduction: In NSCLC major improvements in diagnostics and treatment increased overall survival in the last decades. As a consequence, the number of patients with identified secondary malignancies has risen. Material and Methods: To identify clinicopathological characteristics and a potential prognostic impact of second order cancers, we retrospectively analyzed a pooled NSCLC patient cohort from two academic centers with focus on additional cancers. Results: Of 1012 NSCLC patients (median age 63.3 yrs, 27.2% female, 90.4% eversmokers, 49.9% adenocarcinoma, 49.2% TNM stage IV), 188 (18.6%) showed at least one additional malignancy [15/188 (8.0%) ≥ 2 additional cancers]. Of them, 128 (69.2%) were diagnosed ≥6 month prior NSCLC diagnosis (pre metachronous secondary cancer), 39 (21.1%) within 6 month before or after NSCLC diagnosis (synchronous secondary cancer), and 18 (9.7%) ≥6 month after NSCLC diagnosis (post metachronous secondary cancer). Genitourinary cancers (32.4%) and headu0026neck cancers (28.7%) were predominant. Besides stage, age, ECOG, BMI, and histology, multivariate Cox regression analysis revealed an improved survival for NSCLC patients with synchronous secondary cancers (HR 0.61 (95%CI 0.42-0.89), p=0.010) and post metachronous secondary cancers (HR 0.39 (95%CI 0.22-0.69), p Conclusion: Almost one out of five NSCLC patients suffered from secondary malignancies. Synchronous or post metachronous second order cancers, however, portray only one third of all secondary malignancies in NSCLC patients and display a substantial better prognosis. Future studies need to determine potential genetic or immunologic predispositions in this less aggressive NSCLC phenotype.