Tobacco smoking impairs survival in lymphoma patients in two finnish population‐based cohorts

Introduction: A few studies have explored the effect of smoking status on the survival after the diagnosis of lymphoma during the modern immunochemotherapy era. Shorter overall survival (OS) has been reported especially in patients with the most pack years smoked. Methods: Deep learning-based algorithm was used to classify smoking status (persistent, former or never) at the time of the diagnosis from medical records from Turku and Tampere University Hospitals in Finland. Lymphoma patients excluding Hodgkin lymphoma from years 2009 to 2019 were identified based on histological diagnosis and followed up for OS and cancer-specific survival. Currently detailed baseline demographics and treatment data are available from Turku cohort only. Survival was analyzed with Kaplan-Meier analysis and hazard ratio for death was calculated using Cox regression with 95% confidence interval. Results: Turku cohort included 1814 and Tampere cohort 1027 patients; 1223 with diffuse large B-cell lymphoma (DLBCL) and 513 with follicular lymphoma (FL). Median follow-up time was 69 months. Smoking status was unavailable for 885 patients (31%). Among the DLBCL patients 583 (57%) had never smoked, 238 were former smokers (23%) and 198 (19%) were persistent smokers. For FL patients respective numbers were 248 (57%), 90 (21%) and 97 (22%). Among all patients from Turku median OS was 127 months for never smokers (reference), 82 months for former (HR 1.30 [1.06–1.60]) and 93 months for persistent smokers (HR 1.30 [1.02–1.65]). Among DLBCL patients median OS was 117 months for never (reference), 56 months for former (HR 1.45 [1.09–1.95]) and 57 months for persistent smokers (HR 1.37 [0.97–1.95]). 5-year survival rate was 63%, 50% and 48% in Turku and 59%, 55% and 40% in Tampere, respectively. Among FL patients, median OS was not reached and their 5-year survival rates were 73%, 75% and 70% in Turku and 81%, 70% and 79% in Tampere, respectively. In Turku cohort, DLBCL patients' baseline Ann Arbor stage was advanced (stage III-IV) in 68%, 69% and 76% never, former and persistent smokers respectively (p = 0.47) and in FL patients the baseline Ann Arbor stage was III-IV in 65%, 70% and 51% (p = 0.14) respectively. Persistent smokers were slightly younger compared to former and never smokers (62 years, 67 yrs and 65 yrs for DLBCL (p = 0.03) and 57 yrs, 67 yrs and 67 yrs for FL (p < 0.001)). Persistent and former smokers were more often male than never smokers (66%, 67% and 45% respectively in DLBCL, (p < 0.001) and 64%, 57% and 43% for FL (p = 0.04)). The research was funded by: This study was financially supported by Finnish Cancer Foundation, State Competitive Research Funds and Juho Vainio Foundation. Keywords: aggressive B-cell non-Hodgkin lymphoma, indolent non-Hodgkin lymphoma, late effects in lymphoma survivors No conflicts of interests pertinent to the abstract.