Disparities between high-impact clinical trials in oncology and disease burden.

Abstract

e17591 Background: Recent research has identified a discrepancy between NIH funding in oncology and various measures of disease burden by tumor type. We sought to identify whether this disparity exists in recent high impact publications. Methods: 833 clinical trials published in five high impact general medicine and clinical oncology journals between January, 2009 and October, 2012 were reviewed. 692 trials were included in this analysis after excluding those that studied >1 tumor type. Disease burden was measured as person-years of life lost (YLLs), reported in the Surveillance, Epidemiology, and End Results database, and disability adjusted life years (DALYs), reported by the World Health Organization. We used a chi square goodness of fit test to compare the overall distribution of trials by tumor type to the distribution of annual YLLs and DALYs. Results: Breast cancer was the most published tumor, accounting for 14% of all trials, followed by lung (13%) and colorectal (7%) cancers. More than half of the trials (56%) were for patients with metastatic disease, and most (81%) were phase 2 and 3 clinical trials. Nearly half of all publications studied targeted therapies (45%), and the majority received industry support (61%). 67% of trials with a comparator arm met their primary endpoint. The distribution of trials by cancer site differed significantly from the distribution of both measures of disease burden (YLLs and DALYs) (both p<0.001). The findings were unchanged in analyses that accounted for the total number of subjects enrolled in the trials (both p<0.001). The most underrepresented malignancies based on burden of disease were lung and pancreatic cancers, while the most overrepresented were breast cancer, leukemia, and melanoma. Conclusions: The number of trials published by tumor type does not directly reflect the burden of these diseases in the population as assessed by YLL or DALY. Future studies examining potential confounders such as funding availability by cancer type or number of unpublished clinical trials may further clarify the observed disparities.