Underrepresentation of vulnerable older patients with cancer in phase II and III oncology registration trials: A case-control study

Objectives: We aimed to determine the proportion of “fit” versus “vulnerable” older patients with cancer included in phase II and III oncology registration trials, as compared to the proportions in a real life oncology setting. Methods: Trial and patient characteristics of older (≥70 years) patients treated at the OECI-designated clinical cancer centre in Kortrijk and included in a phase II or III oncology registration trial were collected retrospectively. These patients were matched individually with randomly-selected patients from the general oncology setting, based on gender, age, tumour type, tumour stage, and treatment intent. Patients' fitness, based on routine Geriatric-8 (G8) screening, was retrieved from prospectively constructed databases. Results: Between November 2012 and October 2018, 218 older patients with cancer were included in a phase II or III oncology registration trial. Of those, 41 cases with a mean age of 76.0 years were included in the analyses. A Fisher's Exact Test revealed a statistical significant difference between cases and matched controls, with a higher proportion of “fit” patients included in phase II or III oncology registration trials compared to the proportion in the matched control group (respectively 70.7% and 41.5%, p <.010). Discussion: We provide evidence for the hypothesis that older patients included in phase II or III oncology trials are significantly fitter than the real life oncology population. Some form of geriatric evaluation should be integrated in future cancer clinical trials to enable stratification according to this parameter and allow subgroup analysis. This will broaden the application and interpretation of trial results.