Patients with depression and/or anxiety prior to a diagnosis of diffuse large B-cell lymphoma (DLBCL) had shorter survival times than patients without a mental health diagnosis, according to a retrospective study led by Dana-Farber Cancer Institute researchers and published in The Lancet Haematology on June 1.

Patients with depression had the lowest survival, with a 37% higher risk of dying from their disease or other causes than patients without a mental health diagnosis. Patients with anxiety also had decreased survival. Nearly one in six patients studied was already experiencing depression and/or anxiety within two years prior to their diagnosis, suggesting that mental health could take a toll on survival for many patients.

The findings point to an urgent need for systematic mental health assessments and interventions for patients with DLBCL, an aggressive form of blood cancer and the most common form of lymphoma.

Most factors that affect survival times for DLBCL patients, such as age and the stage of disease, cannot be changed, but depression and anxiety can. "Anxiety and depression are conditions that are treatable, and treatment could potentially impact survival for our patients," says Oreofe O. Odejide, MD, MPH, who led the research and is a physician in Adult Lymphoma and the Division of Population Sciences at Dana-Farber.

Odejide, who treats patients with DLBCL, had found in her clinical practice that many patients experience anxiety and depression related to their cancer diagnosis. Previous research had linked mental health and survival in breast cancer, but there were few studies focused on lymphoma and no published studies of DLBCL, which is most frequently diagnosed in older adults.

Odejide was also motivated by the fact that, in recent years, treatment of lymphoma has improved with the advent of immunotherapy and targeted therapies. More patients are living longer, so mental health is becoming an even more important consideration. "We need to not only help our patients live longer, but also we want to ensure that they are living well by addressing mental health issues," Odejide says.

To try to understand the effects of depression and anxiety on patients with DLBCL, Odejide and her colleagues used the National Cancer Institute's Surveillance, Epidemiology, and End Results-Medicare (SEER) database, which collects clinical and survival data from cancer registries across the US.

Using the database, the researchers identified 13,244 patients who had been diagnosed with DLBCL at age 67 or older between 2001 and 2013. They noted pre-existing depression or anxiety prior to a DLBCL diagnosis and tracked the date and cause of death for each patient to calculate survival time from the date of DLBCL diagnosis. This is the largest retrospective cohort analysis assessing the association between mental health disorders and mortality in patients with a blood cancer and the first specifically for patients with DLBCL.

The researchers compared survival for patients with and without a pre-existing mental health disorder. The data analysis showed that pre-existing depression and/or anxiety in patients with DLBCL were associated with lower survival times.

Of the patients studied, 16% had pre-existing depression and/or anxiety. But that number could be an underrepresentation, since it is based on retrospective medical claims data that might be missing information, such as diagnoses of mild symptoms. Further, a cancer diagnosis can be destabilizing and contribute to the development of anxiety and depression, suggesting that mental health interventions could benefit a substantial number of patients.

Based on these findings, Odejide suggests that physicians treating patients with DLBCL should ask patients about their mental health and refer them to experts or support services if they are experiencing anxiety or depression. "You need to know who is experiencing these disorders to be able to act on them," says Odejide. "And these aren't topics people will typically volunteer on their own if they aren't screened or asked."

The researchers were not able to determine what factors, if any, link these mental health conditions to decreased survival times. It could be that patients coping with depression or anxiety get diagnosed later. Or these patients might have barriers, such as limited financial or social support, that make it harder for them to adhere to a treatment plan. It is also possible that the relationship is not causal.

"This paper is a first step that lays the groundwork for future investigation to figure out which factors, if any, explain this association between anxiety and depression and survival," Odejide says.

In addition, the researchers note that the dataset is limited to a population of patients in the U.S. In other countries or regions, the prevalence and impact of mental health disorders on patients with lymphoma could be different.