Tumor epidermal growth factor receptor genotype and depression in stage IV non-small cell lung cancer.

INTRODUCTION: Depression appears to be associated with worse survival from cancer, but underlying mechanisms for this association are unknown. In the present study, we explored the degree to which tumor genotype may be associated with depression in patients with non-small cell lung cancer (NSCLC). We examined differences in depression severity and rates of positive screens for major depressive disorder among newly diagnosed patients with stage IV NSCLC and known epidermal growth factor receptor (EGFR) genotype.
METHODS: Newly diagnosed patients (n = 53) with metastatic NSCLC attending an initial thoracic oncology consultation completed self-report questionnaires regarding demographics, smoking behavior, and depression before meeting with their oncologist. Biopsy samples were subsequently genotyped, including screening for EGFR mutations. We conducted a retrospective chart review to obtain clinical data, including tumor stage, performance status, and EGFR genotype.
RESULTS: Twelve patients (22.6%) tested positive for EGFR mutation. No EGFR mutation-positive cases met the screening criteria for major depressive disorder, in comparison with 29.3% of patients with wild-type EGFR (p = .03). Mutations of EGFR were also associated with lower depression severity than with wild-type EGFR, independent of gender, performance status, and smoking history (p < .05). This finding persisted for both the cognitive-affective and somatic domains of depression symptoms.
CONCLUSIONS: EGFR mutations were associated with lower depression severity and lower rates of probable major depressive disorder in patients with metastatic NSCLC, based on mood screening performed before results of genotyping were known. Findings support further work to explore the directionality of the associations and potential biological pathways to depression.