High risk of lung cancer in surfactant-related gene variant carriers.

RATIONALE:Several rare surfactant-related genes variants associated with interstitial lung disease are suspected to be associated with lung cancer, but data are missing. OBJECTIVES:We aimed to study the epidemiology and phenotype of lung cancer in an international cohort of surfactant-related gene (SRG) variant carriers. METHODS:We conducted a cross-sectional study of all adults with SRG variants in the OrphaLung network and compared lung cancer risk with telomerase-related gene (TRG) variant carriers. RESULTS:We identified 99 SRG adult variant carriers (SFTPA1 [n=18], SFTPA2 [n=31], SFTPC [n=24], ABCA3 [n=14] and NKX2-1 [n=12]), including 20 (20.2%) with lung cancer (SFTPA1 [n=7]; SFTPA2 [n=8], SFTPC [n=3], NKX2-1 [n=2] and ABCA3 [n=0]). Among SRG variant carriers, the odds of lung cancer was associated with age (odds ratio [OR] 1.04 [95% CI 1.01-1.08]), smoking (OR 20.7 [6.60-76.2]) and SFTPA1/SFTPA2 variants (OR 3.97 [1.39-13.2]). Adenocarcinoma was the only histological type reported, with PDL1 expression≥1% of tumor cells in 3 cases. Cancer staging was localized (I/II) in 8 (40%) individuals, locally advanced (III) in 2 (10%) and metastatic (IV) in 10 (50%). We found no somatic variant eligible for targeted therapy. Seven cancers were surgically removed, 10 received systemic therapy, and 3 received the best supportive care according to their stage and performance status. The median overall survival was 24 months, with stage I/II cancers showing better survival. We identified 233 TRG variant carriers. The comparative risk (subdistribution hazard ratio) for lung cancer in SRG patients versus TRG patients was 18.1 [7.1-44.7]. CONCLUSION:The high risk of lung cancer among SRG variant carriers suggests specific screening and diagnostic and therapeutic challenges. The benefit of regular CT scan follow-up should be evaluated.