Mental Illness's Effect on Breast Cancer Survival
Mental Illness can have a severe impact on an individual’s quality of life and is prevalent in the United States. There has been a recent increase in mental illness awareness campaigns over the past couple of decades, but the US still has a long way to go.
According to the National Alliance on Mental Illness (NAMI) 18.5 percent of adults in the United states experience some form of mental illness in a given year. Of these people, 4 percent experience mental illness that is severe enough to impact his or her daily functioning. Even more substantially, 21.4 percent of youth ages 13 to 18 experience a severe mental disorder at some point. NAMI also reports that people with mental illness face an increased risk of developing chronic medical conditions that are largely treatable. On average, these individuals die 25 years earlier than people without mental illness, largely due to a lack of treatment of medical conditions.
Mental illness and breast cancer
Dave Levitan has recently published in the Cancer Network about how breast cancer patients with mental illness have a higher mortality risk. A recent study has shown that elderly breast cancer patients with mental illness have double the risk of death from all causes compared to people without mental illness. Death due specifically to breast cancer was also higher for this group, but not significantly. Melissa L. Santorelli, PhD, of Rutgers School of Public Health in Piscataway, New Jersey along with other authors of the study wrote that, “Although the literature seems to support a positive association between mental illness and mortality among patients with breast cancer, only one known study used a competing risk analysis to study the effects on breast cancer–specific mortality, and few studies have examined the effect of specific pre-existing mental health conditions on survival outcomes.” This means that more research about the effect of mental illness specifically on breast cancer outcomes is needed.
The researchers sought to shed some light on this topic by conducting a retrospective cohort study using Medicare data. They looked at 19,028 women over the age of 67 who had been diagnosed with stage II to IIIa breast cancer between 2005 and 2007. They defined severe mental illness as diagnoses of “bipolar disorder, schizophrenia, or other psychotic disorders during the 3 years prior to a breast cancer diagnosis.”
They found that there were 496 patients with severe mental illness, and 15,233 without mental illness. They also found that 1,151 had anxiety, 1,465 had depression, and 683 had both diagnoses. They followed the patients for 5 years after diagnosis to analyze survival and then compared these results to patients who did not have mental illness.
The end results showed that the incidence of mortality by any cause in patients with severe mental illness was 38 percent compared with 19.4 percent in people without mental illness. For breast cancer-specific mortality, the rates were 7.2 percent with mental illness and 6.2 percent without. The researchers adjusted their results accounting for age, income, race, ethnicity, location, and marital status. After those adjustments were made, they concluded that people with severe mental illness had a hazard ratio for mortality due to any cause of 2.19 compared to the group without mental illness. The breast cancer specific mortality hazard ratio was 1.20 compared to the group without mental illness. The authors note in their results section that there was a 20 percent increase for mortality hazard due to breast cancer specific reasons, but that this was not statistically significant. The authors did note that late stage diagnosis of breast cancer occurred more frequently in people with severe mental illness compared to those without.
So, what does all this mean?