Patients with advanced lung cancer and depression whose depressive symptoms increased after diagnosis were found to have significantly earlier mortality compared to patients whose depression improved or stayed the same, according to a new study. This relationship was found to persist even among patients who received treatments associated with improved survival in advanced lung cancer. The study was published in Psychosomatic Medicine.
Investigating Lung Cancer and Depression
“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,” wrote the authors. According to the study authors, this is the first study to investigate the relationship between the trajectory of depression and lung cancer survival outcomes.
“Previous studies have just looked at depression at the time of diagnosis and shortly thereafter to predict survival,” said lead author Barbara Andersen, PhD, professor of psychology at The Ohio State University, via a press release. “But this study shows that what happens to depression levels after diagnosis and in the months thereafter are key to understanding how depression relates to premature death.”
This study enrolled patients with stage IV non-small cell lung cancer (NSCLC) at diagnosis. In total, 157 patients were included. Assessments of depression and anxiety symptoms were the Patient Health Questionnaire-9 (PHQ9) and Generalized Anxiety Disorder-7 (GAD7), respectively. Questionnaires were completed every one to two months through two years, for a total of 16 total assessments. The average completion rate was 80%.
The researchers used joint statistical models to conduct simultaneous modeling of psychological and survival processes. The team controlled for age, sex, marital status, education, smoking status, cancer type, and treatment type.
Progression of Depressive Symptoms Linked to Survival
In this population, 28% of patients had moderate depressive symptoms at diagnosis and 8% had moderate to severe symptoms. The remaining patients had lower levels of depression.
Overall, depression and anxiety symptoms significantly decreased as time passed from diagnosis. Patients who did not show improvement in depression symptoms and reported moderate-to-severe levels at three months post-diagnosis had a 15-month survival rate of around 30%, compared with 50% among patients with no depression or mild levels at three months.
The two-year trajectory of depressive symptoms after diagnosis was found to be significantly associated with survival (hazard ratio=1.09 per unit increase in PHQ9, 95% confidence interval 1.03-1.15, P=0.002). This relationship remained significant even after adjustment for covariates.
Regarding anxiety, the impact of these symptoms on survival was found to be marginally significant in the unadjusted model (P=0.053), but not after covariate adjustment (P=0.39).
“We found in this study, for the first time, that even as impressive new treatments are coming online, their efficacy may be constrained for those patients also struggling with depression,” said Dr. Andersen. “These data are novel in suggesting continuing depression as a significant limiting factor, even when the best therapies we have for lung cancer are being used.”
She continued, “We need to help these patients, not only at diagnosis, but throughout treatment to take depressive symptoms out of the equation and let these impressive new therapies do their jobs.”