Representativeness of oncology clinical trials in Alberta.
27 Background: The Institute of Medicine encourages broad participation by patients in clinical trials to “efficiently provide practice-changing evidence”. Enrolment of a representative sample of the general oncology population in clinical trials is essential to ensure that outcomes are generalizable and to ensure equity and social justice. Our aims were to 1) determine the characteristics of all cancer patients compared to those enrolled on a clinical trial and 2) to determine factors and outcomes associated with clinical trial participation. Methods: We assembled a large cohort of patients diagnosed with all solid malignancies between 2004 and 2016 in a large Canadian province. We collected information on age, sex, tumor type, Charlson comorbidity index (CCI), year of diagnosis, treatment type (surgery, chemo, radiation, and immunotherapy). Logistic regression was used to identify factors associated with clinical trial participation. Cox regression models were constructed to determine overall survival (OS). Results: We identified 146,294 patients with a cancer diagnosis, of which 43% were men and the mean age at diagnosis was 61 years (SD 15.6). Approximately 3% (4,364/146,294) of all patients were enrolled in a clinical trial. Baseline characteristics showed that clinical trial patients were younger (mean age 58 years vs 61 years), had fewer comorbidities (CCI 0 = 83% vs. 73%) and more often male (45% vs 43%). Compared to all patients, clinical trial patients were more likely to be younger (OR 0.98, p < 0.001), male (OR 1.21, 95% CI 1.10-1.32 p < 0.001), and to have a diagnosis of brain (OR 3.8, 95% CI 2.86-5.05, p < 0.001), kidney (OR 2.61, 95% CI 1.93-3.52) or breast cancer (OR 2.38, 95% CI 1.84-3.08). Compared to all patients and those not treated on clinical trial, patients on clinical trial had improved OS (HR 0.81, 95% CI 0.77-0.85, p < 0.001). Conclusions: Only a small proportion of real world patients are treated within a clinical trial. Characteristics of clinical trials patients are significantly different from all patients with cancer. More representative clinical trials are needed in order to reflect the real world cancer population.