Population-based comparison of cancer survival outcomes in patients with and without psychiatric disorders.

BACKGROUND: Individuals with psychiatric disorders (PD) have a high prevalence of tobacco use. Patients with PD also potentially receive substandard care in comparison to the general population. Previous research has shown that individuals with PD have a decreased risk of receiving a tobacco related (TR) cancer diagnosis. To further assess this trend, this study assesses the survival of patients with a TR cancer with or without a PD. MATERIALS AND METHODS: Our study utilized multiple databases, with methods described elsewhere,6 to identify people in British Columbia that have been diagnosed with psychiatric disorders and appendicitis (our control group). From these groups, we selected individuals who also had a TR cancer. We subsequently extracted information pertaining to these patients from these databases. RESULTS: Thirty-nine thousand eight hundred forty-one patients with cancer were included in our study. Analyses of these patients were controlled for by age, gender, cancer type and diagnosis year. This analysis displayed shorter survival time among patients who were diagnosed with depression (HR = 1.16; p = 0.01; 95% CI: 1.04-1.29), schizophrenia (HR = 1.62; p < 0.01; 95% CI: 1.43-1.84), or bipolar disorder (HR = 1.35; p < 0.01; 95% CI: 1.12-1.64) compared to the cancer patients without a PD, all of which were statistically significant. People that were diagnosed with anxiety disorders did not have a survival time that was significantly different from our control population (HR = 1.07; p = 0.22; 95% CI: 0.96-1.19). CONCLUSIONS: Individuals with PD, except for those with anxiety, were found to have a shorter survival time following diagnosis with a TR cancer as compared to our control group. We hypothesize several factors, which may account for this statistically significant difference: (1) delayed diagnosis, (2) poor access to care, (3) poor assessment or follow-up, or (4) physician beliefs of poor treatment adherence.

Identification of Tobacco-Related Cancer Diagnoses among Individuals with Psychiatric Disorders: A Population-Based Matched Cohort Study Using a Competing Risks Approach from British Columbia.

BACKGROUND: Individuals with psychiatric disorders (PD) have a high prevalence of tobacco use. Therefore, we assessed the hazard of receiving a tobacco-related (TR) cancer diagnosis among individuals with PD. METHODS: Several population-based provincial databases were used to identify individuals in BC diagnosed with depression, schizophrenia, bipolar disorder, anxiety disorders, or multiple PD between 1990 and 2013. A primary population proxy comparison group (appendicitis) was also identified and matched to the psychiatric cohort based on age at cohort entry, gender, year of cohort entry, and postal code. We linked individuals in the cohort and comparison groups with the BC Cancer Registry. Using a competing risks approach, we estimated the effect of having a PD on the risk of receiving a TR cancer diagnosis, in light of the competing risk of mortality. RESULTS: In total, 165,289 patients were included. Individuals with depression (HR = 0.81; p < 0.01; 95% CI: 0.73-0.91), anxiety disorders (HR = 0.84; p = 0.02; 95% CI: 0.73-0.97), or multiple PD (HR = 0.74; p < 0.01; 95% CI: 0.66-0.83) had a statistically significant lower risk of a TR cancer diagnosis compared to the comparison group. Individuals with schizophrenia (HR = 0.86; p = 0.40; 95% CI: 0.62-1.21) or bipolar disorder (HR = 0.58; p = 0.12; 95% CI: 0.29-1.14), however, showed no evidence of a statistically significant difference from the comparison group. INTERPRETATION: We found that individuals with depression, anxiety disorders, or multiple PD diagnoses had a significantly reduced risk of receiving a tobacco-related cancer diagnosis. These results were unexpected and could be explained by individuals with a PD having barriers to a cancer diagnosis rather than a true decreased incidence.

Population-based assessment of relationship between volume of practice and outcomes in head and neck cancer patients treated in a provincially coordinated radiotherapy program.

BACKGROUND AND PURPOSE: Literature suggests that higher volumes of practice are associated with better survival outcomes for head and neck cancer (HNC) patients. The objective of this study was to evaluate the effect of treatment center on the overall survival (OS) and cancer-specific survival (CSS) in a provincially coordinated program. MATERIALS AND METHODS: A population-based provincial database was used to identify all patients in BC diagnosed for the first time with a primary non-thyroid HNC and treated with radiotherapy between 2006 and 2011. RESULTS: 2330 HNC patients were included. On multivariable analysis, after controlling for age, gender, cancer stage, anatomical site, treatment and physician case frequency, OS (HR range=0.91-1.05; p=0.60-0.88) did not significantly differ by center. OS was also not significantly different for patients treated by physicians with low case frequency (HR=0.96; 0.81-1.13; p=0.60) and medium case frequency (HR=1.12; 0.84-1.49; p=0.43) in reference to high case frequency. There was no effect on OS or head and neck CSS when physician case frequency was treated as a continuous variable. CONCLUSIONS: In our provincially coordinated radiotherapy program, there was no significant difference in survival between cancer centers after controlling for differences in rurality, physician case volume and other potential confounding variables.