Background: The current study examined the extent to which depression and functional limitations contribute to the mortality of newly diagnosed cancer patients. The analysis focused on differences in survival times among cancer patients with new experiences of depressive symptoms and functional limitations and patients with a history of such limitations.
Methods: Data for the current analysis came from two panel studies conducted in Michigan between 1993 and 1997, including 871 adult (> or = 21 years of age) breast, colon, lung, and prostate carcinoma patients. Information came from four separate sources: the intake patient interview, a self-administered questionnaire, medical record audits, and the Death Certificate Registry of Michigan's Department of Community Health. With time to death as the primary outcome (followup of 571 days), data were analyzed using Kaplan-Meier product limit estimates and the Cox proportional hazard model.
Results: Cancer patients who, after diagnosis, report only new depressive symptoms or functional limitations, have the same survival chances as those who report none. Cancer patients with either previous emotional problems or previous physical limitations face, within the first 19 months after diagnosis, a 2.6 times greater hazard of dying than patients without prior problems. Patients with both previous emotional problems and physical limitations before diagnosis have a 7.6 times greater hazard of dying within that time frame.
Conclusions: The current data show cancer patients with prior limitations and emotional problems have worse survival chances than would be expected on the basis of their cancer diagnosis alone. While depressive symptoms and functional limitations are common short-run responses to a cancer diagnosis and initial treatment, patients with no prior history of such problems appear to be more resilient.