Lung cancer remains the number one cause of cancer-related mortality worldwide, but less known is that lung cancer patients are among the most psychologically disabled of all cancer groups. Patients with stage-IV non-small cell lung cancer (NSCLC) were studied to test the hypothesis that trajectories of depression and/or anxiety symptoms following diagnosis would show an adverse relationship with survival, beyond relevant controls.
Patients with stage-IV NSCLC (N = 157) were enrolled (ClinicalTrials.gov Identifier: NCT03199651) at diagnosis and completed validated measures for depressive symptoms (Patient Health Questionnaire-9; PHQ9) and anxiety symptoms (Generalized Anxiety Disorder-7; GAD7). Patients were reassessed every 1-to 2-months thru 24-months (16 assessments; 80% average completion rate) and survival monitored. Joint statistical models provided simultaneous modeling of longitudinal (psychological) and time-to-event (survival) processes. Control variables were age, sex, marital status, education, smoking status, cancer type, and treatment received.
Depression and anxiety symptoms significantly decreased with time since diagnosis. The two-year trajectory of depressive symptoms was significantly associated with cancer survival after adjustment for covariates [Hazard ratio = 1.09 per unit increase in PHQ9, 95% CI 1.03-1.15, p = 0.002]. Anxiety was marginally significant in the unadjusted (p = 0.053) but not the adjusted (p = 0.39) model.
For the first time, joint model analyses test the interaction of a longitudinal trajectory of psychological symptoms, assessed from diagnosis through 24 months, and cancer survival. New data show the continuation of depressive and anxiety symptoms through treatment and thereafter. Immunotherapy and targeted therapies have dramatically improved survival for patients with advanced NSCLC, however novel data suggest their benefit may be constrained by depressive symptoms.