Older, Hispanic Patients More Likely to Withdraw From Cancer Trials

Cancer patients are more likely to withdraw from clinical trials if they are older, Hispanic, and participating in a placebo-controlled study, according to research published in JAMA Oncology.

The research also revealed that the risk of withdrawal was highest within 2 years of enrollment. Furthermore, the overall rate of withdrawal increased over the 6-year period analyzed.

For this study, researchers analyzed data from 11,993 cancer patients enrolled in 58 clinical trials through the Alliance for Clinical Trials in Oncology. The goal was to determine the rates of, and factors associated with, consent withdrawal, which was defined as voluntary termination of consent by the patient at any time during a trial.

At trial registration, 61% of patients were younger than 65 years of age, 27% were 65-74 years, and 12% were 75 years of age or older. Most patients were women (67%) and White (82%). Most trials involved experimental therapeutics or rare tumors, hematologic cancers, gastrointestinal cancers, genitourinary cancers, or nervous system cancers. Placebo was used in 22% of trials.

The rate of withdrawal within 2 years of enrollment was 9%. During the first 3 months of a trial, the withdrawal rate was nearly 4%, but the rate decreased to below 2% between 3 and 6 months. The 2-year rate of withdrawal increased between 2013 to 2019, from 5.7% to 9.8%.

In a multivariate analysis, both patient- and trial-related factors were significantly associated with withdrawal of consent. Hispanic patients were more likely to withdraw from a trial than non-Hispanic patients (odds ratio [OR], 1.67; 95% CI, 1.30-2.15; P <.001).

Patients who were 75 years of age or older were more likely to withdraw consent than patients in other age groups (OR, 1.39; 95% CI, 1.12-1.72; P =.003).

Clinical trials with a placebo control had higher odds of patient withdrawal as well (OR, 1.64; 95% CI, 1.38-1.94; P <.001).

On the other hand, receipt of radiation therapy was associated with an increased likelihood of staying in a trial (OR, 0.68; 95% CI, 0.54-0.86; P =.001).

“[A]n important message from this work is that, across the board and at the very least, educational efforts geared toward patients and study personnel on the topic of withdrawal of consent should be deployed to improve retention rates,” the researchers wrote. “Factors that are associated with withdrawal of consent should be considered when designing future cancer clinical trials.”

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.

Reference

Hillman SL, Jatoi A, Strand CA, Perlmutter J, George S, Mandrekar, SJ. Rates of and factors associated with patient withdrawal of consent in cancer clinical trials. JAMA Oncol. Published online June 22, 2023. doi:101001/jamaoncol.2023.1648