Comparison of clinical outcomes among cancer patients treated in and out of clinical trials

It is unknown if participation in a cancer clinical trial confers clinical benefits to patients. There is not enough scientific evidence in this regard and the available publications are scarce and provide ambiguous and limited information.

Compare overall and progression-free survival and response to treatment among those who met the eligibility criteria and accepted to participate and those who refused to participate in cancer clinical trials.

An observational cross-sectional study with an analytical component was carried out, which included patients diagnosed with cancer who participated in phase III clinical trials and patients who, being eligible, refused to participate. The patients were cared for at the National Institute of Cancerology in Colombia between 2019 and 2022. Analysis of differences in proportions and means of sociodemographic and clinical variables was included; overall survival and progression-free survival time were described and the survival curves between groups were compared. Variables related to survival were determined using a Cox regression model and Hazard Ratios were calculated.

62 women and 50 men were included. In the women group, we found a statistical association between clinical trial participation and non-serious events adverse and progression. The stable disease and complete response were higher in participants than in refusers. The median progression-free survival for refusers was 7,4 m meantime for participants the median was not reached and 74,1% remained without progression at 28 months. In the men group, we also found a statistical association between clinical trial participation and the occurrence of non-serious events adverse meanwhile there were no significant differences in overall response, progression, and death, even though the proportion of progression was minor in participants 20% vs. refusers 26% respectively. The median survival was not reached for any group, even though in the participants group 55,2% were still alive at month 20 and in the refusers group still alive at 56,8% at month 45. Covariables included for the multivariate Cox regression only age had a statistical association with overall survival in the women’s group and the men group any covariables reached statistical association.

It can be considered that participation in clinical trials could give participants a better response to treatment, without increasing the probability of death and with the probability of decreasing the progression of the disease. Participation in trials could improve the outcomes of clinical response rates, no change in overall survival, and progression-free.