Patients diagnosed with cancer faced an increased risk for common mental disorders — such as depression, anxiety and stress reaction/adjustment disorder — for up to 10 years, according to the results of a matched cohort study conducted in Sweden.
The risk for mental disorders appeared stronger among patients whose cancers had poorer prognoses, results showed.
“Our previous work has shown highly increased risks for suicide and cardiovascular events among patients with cancer,” Donghao Lu, MD, PhD candidate in the department of medical epidemiology and biostatistics at Karolinska Institutet in Stockholm, told HemOnc Today. “These events, however likely, only represent the tip of the iceberg for the enormous psychological turmoil related to a newly received cancer diagnosis. Further, accumulating evidence suggests that the cancer diagnostic workup may also bring about severe psychological distress.”
However, the degree to which diagnostic workups may increase the risk for stress-related health outcomes, such as mental disorders, remains unknown, Lu said.
Lu and colleagues evaluated 2001 to 2010 data from Swedish population and health registers. They identified 304,118 patients with cancer (median age at diagnosis, 69 years; 46.9% female), as well as 3,041,174 cancer-free controls whom they matched to patients based on sex and year of birth.
The researchers estimated time-varying HRs — adjusted for age, sex, education level and calendar period — for the first clinical diagnosis of mental disorders beginning 2 years before cancer diagnosis, continuing through the time of diagnosis and for up to 10 years after diagnosis.
Key study endpoints included the relative risks for depression, anxiety, substance abuse, somatoform/conversion disorder, and stress reaction/adjustment disorder during the periods preceding and following a cancer diagnosis, as compared with individuals without cancer.
Overall, there were 3,355 patients with a new mental disorder diagnosis in the prediagnostic period, and 10,296 patients with a new mental disorder in the postdiagnostic period.
The researchers observed an increase in the relative rate for all studied mental disorders beginning 10 months before a cancer diagnosis (HR = 1.1; 95% CI, 1.1-1.2). The increase reached its peak in the first week following diagnosis (HR = 6.7; 95% CI, 6.1-7.4).
Although a steady decrease began following the peak period, patients with cancer still experienced an elevated risk for mental disorders up to 10 years after receiving their diagnosis (HR = 1.1; 95% CI, 1.1-1.2).
The risk appeared comparable for all disorders studied; however, the highest rate occurred for stress reaction/adjustment disorder immediately following diagnosis.
Women appeared at greater risk for mental disorders than men immediately before (HR = 1.9 vs. HR = 1.7) and immediately following (HR = 7.6 vs. HR = 5.4) diagnosis. Younger patients and those with higher education levels had higher HRs after diagnosis but not before.
The increased risk for mental disorders persisted across cancer types, with the exception of nonmelanoma skin cancer.
Patients with poorer-prognosis cancers had higher relative rates before and after diagnosis (P < .001 for both). Having advanced or metastatic cancers did not increase risk for mental disorders compared with localized or nonmetastatic disease; however, mental disorders occurred more frequently by the end of follow-up among patients with locally advanced cancer and those with metastatic breast and lung cancers.
To assess milder mental conditions and symptoms, Lu and colleagues evaluated the use of related psychiatric medications among patients diagnosed with cancer in 2008 and 2009.
Compared with matched controls, patients with cancer used psychiatric medications more frequently 1 month before diagnosis (12.2% vs. 11.7%; corrected P = .04). This rate peaked 3 months after diagnosis (18.1% vs. 11.9%; corrected P < .001) and then declined, but still remained elevated 2 years after diagnosis (15.4% vs. 12.7%; corrected P < .001).
The greatest use of psychiatric medicines occurred among patients with lung cancers, central nervous system cancers and other severe conditions. Conversely, patients with nonmelanoma skin cancer had no increase.
The researchers acknowledged their reliance on inpatient and outpatient specialist care to determine clinical diagnoses as a study limitation.
“Our findings support the existing guidelines of integrating psychological management into cancer care, and call for the extended vigilance for multiple mental disorders in cancer care,” Lu said. “We are currently examining the temporal pattern of stress experience, as well as its related health outcomes, within the time period of the cancer diagnostic workup and by patient characteristics. Our aim is to identify specific time windows or high-risk groups for potential clinical intervention.” – by Cameron Kelsall
For more information:
Lu, MD, can be reached at firstname.lastname@example.org.
The researchers report no relevant financial disclosures.