Worsening depression symptoms are associated with shorter survival for lung cancer patients, while conversely, when depression symptoms lift, survival tends to improve.
The negative effect of depression was particularly noticeable for those in the early stages of disease, say the researchers.
On the other hand, if depression can be reduced, the negative effects are eliminated.
“Surprisingly, depression remission was associated with a mortality benefit as they had the same mortality as never-depressed patients,” said lead author Donald R. Sullivan of Oregon Health and Science University in Portland.
“This study cannot prove causation — but it lends support to the idea that surveillance for depression symptoms and treatment for depression could provide significant impact on patient outcomes, perhaps even a mortality benefit,” explains Sullivan.
The researchers followed more than 1,700 patients newly diagnosed with lung cancer between 2003 and 2005 who had completed an eight-item depression assessment at diagnosis and again 12 months later.
Almost 40 percent, 681 people, had depressive symptoms at diagnosis and 14 percent, 105 people, developed new-onset symptoms during treatment.
Overall, those who were depressed at the beginning of the study period were 17 percent more likely to die during follow-up than those without depressive symptoms.
The study appears online in the Journal of Clinical Oncology.
Compared to the 640 people who never developed depression symptoms, the 105 with new-onset symptoms were 50 percent more likely to die. Another 254 people whose depression symptoms persisted throughout the study period were 42 percent more likely to die.
However, those who had depressive symptoms at diagnosis but did not have them one year later had a similar risk of death to those who were never depressed. The researchers did not have any data on how or why these patients experienced depression remission.
“We have known since the 1970’s that a cancer diagnosis sets off a period of existential plight, a period that lasts about 100 days during which people ask questions of life and death and worry about their health and the meaning of their physical symptoms,” said Mark Lazenby, associate professor at the Yale School of Nursing in New Haven, Connecticut and a member of Yale Cancer Center.
“Although from this study we cannot say that treating depression would extend survival, other studies have shown that care aimed at improving the psychosocial well-being, which includes but is not limited to detecting and treating depression, does have a survival benefit,” explains Lazenby.
Depression impacts quality of life and has been associated with missed appointments and lower adherence to recommended therapies, which could impact morality, Sullivan noted.
“Most of all, I believe a positive attitude, fighting spirit, and coping ability significantly impact a patient’s ability to persevere in the face of a life-threatening illness,” he said. “This is likely why married patients and those with strong social support networks have better cancer outcomes — having a ‘community’ to help share the emotional burden is essential.”
Mental and physical health are inextricably linked, he added.
“Clinicians have to do a better job of treating the whole person and not focusing on the disease only,” Sullivan said.
“From the patients’ perspective, hopefully some of them will take a look at this study and realize the feelings they are experiencing are common and they will feel empowered to advocate for themselves and ask their clinicians for help or resources when they need it.”