Socioeconomic deprivation in patients with cancer was associated with worse overall, progression-free, and cancer-specific survival compared with patients from more affluent areas. These findings were presented at the American Society of Clinical Oncology Quality Care Symposium, held in San Diego, California.
Patients with cancer who live in socioeconomically disadvantaged areas have been shown to have worse outcomes. But because trial participation is based on eligibility criteria and care is directed by the trial protocol, the effects of area-level socioeconomic deprivation have not been systematically evaluated in clinical trial participants.
For this study, the researchers examined survival among 41,182 patients enrolled in 55 phase 3 clinical trials conducted by SWOG from 1985 to 2012, comprising 24 cancer histology and stage-specific strata.
To determine area-level socioeconomic deprivation, the researchers linked trial participants’ residence zip codes to the Area Deprivation Index (ADI). ADI is a comprehensive index used to rank neighborhoods based on select socioeconomic domains scored from 0 to 100 and split into quintiles. Cox regression was used to examine 5-year overall survival, progression-free survival, and cancer-specific survival. Adjustments were made for age (in 5-year intervals), sex, and race (black vs non-black). In a subset of patients, adjustments were made for insurance status (Medicaid/no insurance vs other). Analyses were stratified by cancer histology and stage.
Findings demonstrated that 5-year overall survival (hazard ratio [HR] = 1.26; 95% CI, 1.18-1.35; P <.001), progression-free survival (HR = 1.19; 95% CI, 1.12-1.27; P <.001), and cancer-specific survival (HR = 1.25, 95% CI, 1.17-1.35; P <.001) were worse for clinical trial participants from areas with the highest socioeconomic deprivation (ADI, 80% to 100%) compared with trial participants from the most affluent areas (ADI, 0% to 20%). Adjusting for insurance produced similar results. Risk of an event increased with increases in the ADI quintile.
Area-level socioeconomic deprivation was associated with worse survival, even in patients with access to protocol-directed care and after adjusting for patient-level race and insurance, the researchers concluded. Whether this disparity is due to reduced access to supportive care or treatment after clinical trial participation and/or to health-status differences not revealed in eligibility criteria should be examined in future research. “Policies to mitigate socioeconomic differences in cancer outcomes should emphasize access to cancer care services beyond initial therapy,” concluded the researchers.
Unger JM, Moseley A, Ramsey SD, et al. Socioeconomic deprivation and cancer outcomes in patients treated in clinical trials. J Clin Oncol. 2019;37(suppl 27):abstr 162.