Association of Patient Comorbid Conditions With Cancer Clinical Trial Participation

The American Society of Clinical Oncology (ASCO), Friends of Cancer Research, and the US Food and Drug Administration recently recommended modernizing criteria related to comorbidities routinely used to exclude patients from cancer clinical trials. The goal was to design clinical trial eligibility such that trial results better reflect real-world cancer patient populations, to improve clinical trial participation, and to increase patient access to new treatments in trials. Yet despite the assumed influence of comorbidities on trial participation, the relationship between patients' comorbidity profile at diagnosis and trial participation has not been explicitly examined using patient-level data.

To investigate the association between comorbidities, clinical trial decision-making, and clinical trial participation; and to estimate the potential impact of reducing comorbidity exclusion criteria on trial participation, to provide a benchmark for changing criteria.

A national survey was embedded within a web-based cancer treatment-decision tool accessible on multiple cancer-oriented websites. Participants must have received a diagnosis of breast, lung, colorectal, or prostate cancer. In total, 5499 surveyed patients who made a treatment decision within the past 3 months were analyzed using logistic regression analysis and simulations.

Cancer diagnosis and 1 or more of 18 comorbidities.

Patient discussion of a clinical trial with their physician (yes vs no); if a trial was discussed, the offer of trial participation (yes vs no); and, if trial participation was offered, trial participation (yes vs no).

Of the 5499 patients who participated in the survey, 3420 (62.6%) were women and 2079 (37.8%) were men (mean [SD] age, 56.63 [10.05] years). Most patients (65.6%; n = 3610) had 1 or more comorbidities. The most common comorbid condition was hypertension (35.0%; n = 1924). Compared with the absence of comorbidities, the presence of 1 or more comorbidities was associated with a decreased risk of trial discussions (44.1% vs 37.2%; OR, 0.86; 95% CI, 0.75-0.97; P = .02), trial offers (21.7% vs 15.7%; OR, 0.82; 95% CI, 0.70-0.96; P = .02), and trial participation (11.3% vs 7.8%; OR, 0.76; 95% CI, 0.61-0.94; P = .01). The removal of the ASCO-recommended comorbidity restrictions could generate up to 6317 additional patient trial registrations every year.

Independent of sociodemographic variables, the presence of comorbidities is adversely associated with trial discussions, trial offers, and trial participation itself. Updating trial eligibility criteria could provide an opportunity for several thousand more patients with well-managed comorbidities to participate in clinical trials each year.