Association of Performance Status With Survival in Patients With Advanced Non–Small Cell Lung Cancer Treated With Pembrolizumab Monotherapy

IMPORTANCE: Despite approximately 40% of patients having Eastern Cooperative Oncology Group (ECOG) performance status (PS) scores of at least 2 in the real world, most landmark clinical trials that led to the use of pembrolizumab as standard of care in advanced non–small cell lung cancer (NSCLC) excluded this group. OBJECTIVE: To evaluate whether an ECOG PS score of at least 2 at the start of therapy is associated with progression-free survival (PFS) and overall survival (OS) in advanced NSCLC treated with pembrolizumab monotherapy. DESIGN, SETTING, AND PARTICIPANTS: This cohort study included all consecutive patients with advanced NSCLC who underwent treatment with palliative pembrolizumab monotherapy from February 2016 to October 2019 at a single academic cancer center, with data censoring on January 15, 2020. EXPOSURES: ECOG PS score at start of therapy, with 0 and 1 indicating fully active or restricted in strenuous activity and scores of 2 and higher indicating increasing disability. MAIN OUTCOMES AND MEASURES: PFS and OS, measured from initiation of pembrolizumab monotherapy. RESULTS: Of 74 patients (median [range] age, 68.5 [33-87] years; 36 [48.7%] women; 53 [71.6%] White individuals) with median follow-up of 19.5 (95% CI, 13.4-27.8) months, 45 (60.8%) had an ECOG PS of 0 or 1, while 29 (39.2%) had an ECOG PS of at least 2. There were no significant differences in the baseline characteristics, except in age. Compared with patients with PS scores of 0 or 1, those with PS scores of at least 2 had significantly lower disease control rates (38 [88.4%] vs 15 [53.6%]; P = .002), shorter median PFS (7.9 [95% CI, 4.6-15.4] months vs 2.3 [95% CI, 1.8-4.8] months; P = .004), and shorter median OS (23.2 [14.0 vs 35.7] months vs 4.1 [95% CI, 2.1-6.9] months; P < .001). Among those potentially eligible for subsequent cancer-directed therapy beyond pembrolizumab monotherapy, patients in the group with PS scores of at least 2 were less likely to receive it than those with PS scores of 0 or 1 (2 [8.3%] vs 14 [45.2%]; P = .003). Multivariable adjustment for baseline characteristics confirmed ECOG PS of at least 2 as an independent risk factor for worse PFS (HR, 2.02; 95% CI, 1.09-3.74; P = .03) and worse OS (HR, 2.87; 95% CI, 1.40-5.89; P = .004). CONCLUSIONS AND RELEVANCE: In this cohort study, having an ECOG PS score of at least 2 was associated with poorer prognosis for treatment of advanced NSCLC with palliative pembrolizumab monotherapy. Further prospective studies are needed to evaluate more objective and consistent measures of functional status to facilitate identification of patients with borderline performance status who may achieve durable clinical benefit from treatment with pembrolizumab monotherapy.