Evidence suggests that psychological symptoms are indeed associated with cancer survival. Data shows that people with anxiety and depression tend to have worse survival compared to individuals without symptoms. But an important distinction is that not all psychological symptoms can be lumped together as being linked to the same causes or effects in patients with cancer.
That was the conclusion of a research paper published in the Journal of Psychosomatic Research (2020; doi: 10.1016/j.jpsychores.2020.110218). “Although often considered together as aspects of ‘emotional distress,’ depression and anxiety have different independent associations with survival in patients with cancer and should therefore be considered separately,” the authors noted.
Enter a paper published in PLOS ONE that looked at depression in lung cancer patients, along with systemic inflammation biomarker ratios (2023; doi.org/10.1371/journal.pone.0282206). The data showed highly depressed patients were 1.3-3 times more likely to have high inflammation levels, even after controlling for other factors related to inflammation biomarker levels, including demographics and smoking status. The researchers noted in the paper that the data suggests depression in lung cancer patients is an important factor to consider and treat if present.
“It is normal to be upset, sad, and anxious about a cancer diagnosis, but it is not normal to have major depression,” noted Barbara Andersen, PhD, a lead author of the study and a Professor of Psychology at The Ohio State University.
However, in an interview with Oncology Times, William S. Breitbart, MD, a psychiatrist and the Jimmie C. Holland Chair of the Department of Psychiatry and Behavioral Sciences at Memorial Sloan Kettering Cancer Center, added that another important consideration is the role of cancer and the inflammation associated with it in causing some cases of inflammatory depression in cancer patients, too.
“For many cancer patients who have [certain] cancers, like lung and pancreatic cancer in which there are high rates of depression, those cases of depression are often inflammatory depression. And these are depressions caused by inflammation or associated with inflammation that's produced by the cancer itself or is related to the cancer,” Breitbart said.
There is research that suggests that these cases of inflammatory depressions in people with cancers are actually different (in terms of the neurotransmitter deficiencies they lead to) compared with other types of depression. And that means such cases of depression may respond to different types of antidepressants than other cases of depression, Breitbart noted.
When you're talking about treating depression in these patients, that's an important point, he said. That's because the research on inflammatory depression in cancer is very young. “It's really not well known,” he said. “It's not even widely known among psycho-oncologists.”
The recent study from Andersen's group analyzed data from blood draws and depression self-reports from 186 individuals with newly diagnosed Stage IV non-small cell lung cancer. The blood samples, cell counts of neutrophils (N), lymphocytes (L), and platelets (P) were abstracted for ratio (R) calculations for NLR, PLR, and the advanced lung cancer inflammation index. The presence of symptoms of depression, but not necessarily depression diagnosis, was measured via the Patient Health Questionnaire-9.
Patients were followed and biomarkers were tested as predictors of 2-year overall survival to confirm their relevance. The key findings in the study were as follows:
- “Adjusting for covariates, depression was reliably associated with biomarker levels. Patients with moderate or severe depressive symptoms were 2-3 times more likely to have prognostically poor biomarker levels.”
- “Novel data show patients' depressive symptoms were reliably associated with lung-relevant systemic inflammation biomarkers, all assessed at diagnosis or during pretreatment. The same systemic inflammation ratios were found prognostic for patients' 2-year overall survival.”
Breitbart said it's important to keep in mind that what this paper doesn't show necessarily is that, because these people with lung cancer have inflammation and then have inflammatory depression, it's the depression that contributed in some way to the decreased length of survival.
“This correlation to me doesn't suggest to me an etiology in the sense that the depression is what contributes to the inflammation, and then causes worse survival,” he said.
There is growing evidence that for certain types of cancers, like lung and pancreatic tumors, the inflammation associated with the cancer triggers depressive symptoms, too. Previous research from Breitbart and others has identified specific biomarkers associated with inflammatory depression in lung cancer patients (Psychosomatics 2020; doi: 10.1016/j.psym.2020.03.005).
Other data shows that patients with pancreatic cancer have higher rates of depression even prior to getting a cancer diagnosis, indicating the depression is not necessarily only caused by the emotional distress of receiving a cancer diagnosis, Brietbart noted (BMC Cancer 2010; https://doi.org/10.1186/1471-2407-10-569).
“So, I think the takeaway from this is that, with cancers that have a great deal of inflammation associated with them, there can be a significant incidence of pro-inflammatory depression—and that needs attention because depression can obviously increase morbidity and distress and interfere with adherence to treatment,” Breitbart stated.
It's worth noting that the paper mentions that inflammation may be playing a role in cases of depression.
“A plausible interpretation of this data is a differential effect of depression severity which ‘adds’ to patients' basal level of inflammation arising from other sources,” the research noted. “This may be a contributing mechanism to the uniquely high rates of depression found in [lung cancer] patients at diagnosis and the toxicity of the depression trajectory thereafter predicting lower survival.”
Sarah DiGiulio is a contributing writer.