Depression and Inflammation Predict Depression Trajectory of Non-Small Cell Lung Cancer Patients

Depression and systemic inflammation at diagnosis are associated with poor oncologic outcomes for lung cancer (LC) patients. Research has not explored the interaction of these biomarkers and potential for subsequent psychological morbidity. The aim determines if the co-occurrence of depression and systemic inflammation predicts a worsened trajectory of depressive symptoms from diagnosis through 8 months.

An observational longitudinal cohort design was used (ClinicalTrials.gov Identifier: NCT03199651). Individuals ( N =182) with advanced non-small cell lung cancer were enrolled at diagnosis/pretreatment, had blood drawn, and completed a depression assessment and followed with 8 monthly reassessments. Measures were the Advanced Lung Cancer Inflammation Index (ALI) and self-reported depressive symptoms (Patient Health Questionnaire-9). Using validated cutoffs for biomarkers of inflammation (ALI <24 vs. ALI ≥24) and depression (PHQ <8 vs. PHQ ≥8), the sample was subdivided into 4 cohorts: (1) no/low depression and low inflammation (neither); (2) no/low depression but high inflammation (inflammation); (3) high depression but low inflammation (depression); and (4) high depression and high inflammation (depression+inflammation).

Linear mixed models were tested for Group, Time, and Group × Time effects predicting the depression trajectory, adjusting for baseline depression/inflammation, age, partner status, education, smoking history, and cancer treatment. Overall, depressive symptoms did not change across time ( p =0.26), but as predicted, only for Cohort 4 (depression+inflammation) was the interaction significant [ F(24,945) =-0.04, p =0.001], with patients having an elevated depression trajectory.

Novel data contribute to the depression pathophysiology literature, showing that co-occurring depression and inflammation can predict depression. Clinically, data suggest a new biobehavioral metric for the identification of depression maintenance in LC patients.

ClinicalTrials.gov identifier: NCT03199651.