The youngest population under 50 years old (P50) with lung cancer (LC) in the French nationwide real-life KBP cohorts: Evolution since 2000.
Authors: Falchero Lionel , Laurent Thomas , Quieffin Jean , Pegliasco Herve , Jeandeau Serge , Clarot Caroline , Rabut Hong , Magne Fanny , Kraemer Jean-Philippe , Larive Sébastien , Peloni Jean-Michel , Mairovitz Alexa , Marichy Catherine , Tack Vincent , Bonnefoy Philippe , Benmammar Kheir Eddin , Bordier Soraya , Morel Hugues , Debieuvre Didier 
Published: June 2024

8059 Background: The KBP-CPHG studies are multicenter prospective real-life studies on LC, conducted in France each decade since 2000. We describe the characteristics of the LC in P50, which is a small population and rarely described [1 ], compare it to the oldest population with LC and describe the evolution since 2000. Methods: All patients with LC diagnosed in 2020, in non-academic public hospital were included in KBP 2020. The characteristics of the 8999 patients included in KBP-2020 have already been reported [ 2 ]. Only 428 (4.8%) were P50 and included in this cohort. Here, we describe their characteristics compared to the oldest patients from and over 50 years old and with the previous cohorts (KBP-2000 & 2010). Results: In KBP-2020, among the P50, the proportion of women is 41.1% vs 34.3% (p = 0.004). The proportion of active smokers is greater (79.4% vs 51.5%, p < 0.0001) including more cannabis users (28.3% vs 2.3%, p < 0.0001). P50 are symptomatic in 81.1% of cases, more often have adenocarcinomas 66.8% vs 55.6%, p < 0.0001 and metastatic at diagnosis (67% vs 57.9%, p < 0.001) with brain metastasis in 39.9% of cases. The molecular alterations are more often researched in P50 (72.2% vs 55.4%, p < 0.0001) and we found a significantly higher proportion of ALK rearrangement (7.2% vs 2.1% p < 0.0001) and ROS1 (4.2% vs 1.6 p < 0.007) and less KRAS rearrangement (26.8% vs 35.5% p = 0.013). P50 have significantly better 3-y overall survival (OS) than ≥ 50 years old, 39.2% [34.5 - 44.6] vs 31.5% [30.4 - 32.6], log-rank test for OS, p = 0.0003. Compared to KBP-2000 and 2010, the overall proportion of P50 have been decreasing for 20 years (respectively 12.3%, 8.7% and 4.8%, p < 0.001), with an increasing proportion of women (respectively 24.1%, 38.2% and 41.1%, p < 0.001). The ECOG PS at diagnosis improves (PS 0/1 = 74.3%, 81.0% and 84.0% respectively, p = 0.002). Among the P50, the proportion of non-smokers increases (respectively 4.4%, 9.8% and 11.7%) but there is still a large majority of smokers with a decreasing quantity of tobacco (respectively 35.3 PA, 33.1 PA, 29.1 PA). P50 have significantly better 3y survival in 2020 (39.2% [34.5 - 44.6]) compared to 2000 (19.1% [16.3 - 22.3]). The median OS was 9.8 months [8.9 - 11.2] in 2000, 11.7 [10.3 - 13.8] in 2010 and 21.6 [16.1 - 29.2] in 2020, log-rank test for OS, p < 0,0001. Conclusions: The proportion of P50 with LC has decreased over the last 20 years in France, with an increased proportion of women. In this young population, the proportion of tobacco smokers was still high but has decreased for 20 years and the cannabis consumption was high. Compared to older patients, the PS is better although metastatic diseases were more frequent, and patients were more often symptomatic. Adenocarcinoma was the most frequent histology type.