Abstract Rationale Older adults represent an increasing proportion of patients with early-stage NSCLC, yet data on EGFR mutation prevalence and clinical correlates in octogenarians remain limited. Understanding the mutation spectrum and its prognostic implications in this population could streamline treatment. The goal of this research is to describe the scope of EGFR mutations in octogenarians with clinical stage IA NSCLC, and to compare clinical, radiologic, and pathologic features, between EGFR mutant and EGFR wild-type cases. Methods We analyzed data from the Initiative for Early Lung Cancer Research on Treatment (IELCART) study. Eligible patients had surgery at Mount Sinai, were ≥80 years of age, with clinical stage IA NSCLC (≤30 mm; cT1a-cN0M0, 8th TNM edition) who underwent curative-intent resection after study launch in April 2016 and had genomic profiling available for the resected cancer. Tumors harboring EGFR mutations were identified, and the corresponding demographic, clinicopathologic, surgical, and post-treatment characteristics were reviewed and compared with those having EGFR wild-type tumors. In addition, the frequency of EGFR mutations—stratified into four categories (classic mutations exon 19 deletions and exon 21 L858R substitutions, exon 20 insertions, uncommon variants, and compound mutations defined by the presence of ≥ 2 coexisting EGFR alterations)—were compared with those observed in younger patients within the IELCART cohort. Results Among 70 octogenarians with molecularly characterized NSCLC, 31 (44.3%) harbored an EGFR mutation. Of these, 24 (77%) classic , 2 (7%) exon 20 insertions, 3 (10%) uncommon variants, and 2 (6%) compound alterations. The frequency and distribution of EGFR mutations, when stratified into the four subgroups, were comparable between octogenarians and younger patients (n = 116) (see Figure). EGFR mutants were more often never-smokers (42% vs 10%, p=0.003), less frequently White (68% vs 90%, p=0.10), and more often female (55% vs 45%, p = 0.3) than EGFR wild-type. EGFR-mutated cancers were less solid (48% vs 87%, p0.001) and more often part-solid (39% vs 13%) or nonsolid (13% vs 0%). Pathological stage, surgical modality, and perioperative outcomes were similar between both groups. Survival and recurrence analyses are ongoing and will be updated at the time of presentation. Conclusion 44% of the 70 octogenarians with surgically-resected clinical stage IA NSCLC were EGFR mutants, mostly classical mutations. They were more often never-smokers and had more subsolid tumors. Findings may clarify the biological behavior of EGFR-mutated disease in the elderly and inform tailored management and molecular testing strategies in this underrepresented population. This abstract is funded by: The Simons Foundation
Zhu et al. (Fri,) studied this question.