Patients with cancer run a higher risk of mental disorders not only as they undergo treatment but also as much as a year before diagnosis, a newly published cohort study involving a decade’s worth of patient data from more than 3 million individuals reported in JAMA Oncology.1
“The dramatic risk increases seen immediately after cancer diagnosis are not surprising and corroborate previous findings on highly increased risks of cardiovascular diseases and suicide right after cancer diagnosis,” the study’s corresponding author, Donghao Lu, MD, PhD candidate of the department of medical epidemiology and biostatistics at the Karolinska Institutet in Sweden, told Cancer Therapy Advisor. “However, the clearly elevated risks during the year before diagnosis are new.”
The possible causes, Dr Lu and his coauthors suggested, could involve both the emotional toll and the physical effects of the cancer itself.
“Besides the potential effect of psychological stress experienced during the diagnostic workup,” they wrote, “prediagnostic cancer symptoms and paraneoplastic syndrome (eg, anemia) may also contribute to the increased risk of mental disorders and increased use of psychiatric medications during the prediagnostic period.”
The study involved 304,118 patients with a first cancer diagnosis between January 1, 2001, and December 31, 2010, and 3,041,174 cancer-free individuals. The researchers excluded anyone with previous psychiatric comorbidities in the 2 years before diagnosis. For each patient with cancer, the researchers randomly selected 10 of the cancer-free individuals and matched them based on birth year and sex.
In total, the study identified 3355 patients with a new diagnosis of the studied mental disorders during the prediagnostic period and another 10,296 post-diagnosis. The analysis calculated that hazard ratios (HRs) for psychiatric symptoms started to increase 10 months before cancer diagnosis (HR, 1.1; 95% CI, 1.1 – 1.2) and peaked immediately following diagnosis. They peaked more so in women (HR, 7.6; 95% CI, 6.8 – 8.6) than in men (HR, 5.4; 95% CI, 4.6 – 6.3) and remained elevated for up to 10 years after diagnosis, although not as strikingly.
The authors noted largely similar results for all individual mental disorders studied—including depression, anxiety, substance abuse, somatoform/conversion disorder, and stress reaction/adjustment disorder—with comparable rate elevations before cancer diagnosis among all of the disorders. However, immediately after diagnosis, the highest rate increase was noted for stress reaction/adjustment disorder.
The team also identified an increased use of psychiatric medications beginning the month before cancer diagnosis (12.2% vs 11.7%; corrected P = .04). The use of the medications peaked at around 3 months after diagnosis (18.1% vs 11.9%; corrected P < .001) and then remained elevated 2 years after diagnosis (15.4% vs 12.7%; corrected P < .001).
“Increased use [of these medications] was most pronounced for lung, CNS [central nervous system], and severe cancers, whereas no increased use was noted for nonmelanoma skin cancer,” they said.
The authors also noted that “not only does living with cancer induce severe psychological stress, but being diagnosed as having a cancer is also highly stressful.” And that, Dr Lu told Cancer Therapy Advisor, provides evidence for incorporating long-term psychological care into cancer treatment strategies from the start.
“Our findings support the existing guidelines of integrating psychological management into cancer care,” he said. “And they call for extended vigilance for multiple mental disorders starting from the time of the cancer diagnostic workup.”
- Lu D, Andersson ML, Fall K, Hultman CM, Czene K, Valdimarsdóttir U, Fang F. Clinical diagnosis of mental disorders immediately before and after cancer diagnosis: a nationwide matched cohort study in Sweden [published online ahead of print April 28, 2016]. JAMA Oncol. doi: 10.1001/jamaoncol.2016.0483.