Prevalence [P] of molecular biomarkers [MB] expression [exp] in patients [pts] with metastatic adenocarcinoma lung [MAC]: Illinois CancerCare [ILCC] analysis.

Abstract

e21004 Background: Treatment of MAC is guided by MB. These include Programmed Death Ligand 1 (PDL1), Epidermal Growth Factor Receptor (EGFR), Anaplastic Lymphoma Kinase (ALK) & ROS1. There is little information available on P of MB in US Midwestern population, a largely homogenous Caucasian group. We examined the expression (exp) of the MB in pts with MAC who presented at ILCC in 2018, one of the largest practices in US Midwest. Methods: We conducted a retrospective analysis of all MAC pts who presented at ILCC in 2018. We analyzed the exp of PDL1, EGFR, ALK, and ROS1 in these pts. PDL1 status was defined as high if PDL1 was ≥50%, low if 1- < 50% and -ve if 0- < 1%. High and low groups [all pts with > 1%] were designated +ve. Results: In 2018 there were 125 pts seen at ILCC with MAC. As of 6/2019, 57/125 [46%] pts were alive. Pts: median age 69 yrs [45-89], median PS 1 [0-3], males 62%, current/former smokers 90%, Caucasians 95%. PDL1 results were available in 104/125 pts [83%], EGFR in 95 (76%), ALK in 97 (78%), and ROS1 in 95 (76%). Previously reported papers have described PDL1+ to be as high as 58% in MAC. However, in our study only 53/104 (51%) pts were PDL1+. Though, 26/104 (25%) did have high PDL1 exp [consistent with other reports]. 27/104 (26%) had low PDL1 exp and 51/104 (49%) pts were PDL1-ve. EGFR mutation [M] was found in 11/95 (12%), ALK M was found in 5/97 (5%) pts & ROS1 M was found in 2/95 (2%), the results of these three mutations are consistent with other groups. Conclusions: Our results indicate that exp of PDL1+ pts at ILCC is lower than reported by others, yet the proportion of those with ≥50% PDL1 in our group is similar to others. Exp of EGFR, ALK, and ROS1 in our pts is similar to other studies.[Table: see text]