Clinical trials set the treatment standards for cancer care. However, for select populations, such as those who are older, Black, or facing socioeconomic challenges, access to clinical trials and health care generally remains limited. Barriers to clinical trial participation are numerous and include individual factors such as patient knowledge and awareness, provider characteristics including willingness to offer clinical trials, limited infrastructure to support trials, and geographic access barriers.
This differential access to clinical trials and health care results in disparities in patient-centered outcomes and survival. However, these health effects are further compounded for those residing in communities facing high social vulnerability.1
The Centers for Disease Control and Prevention’s Social Vulnerability Index1 and the Area Deprivation Index2 are two examples of composite measures developed to account for the co-occurrence of community-level social factors. These indices are used increasingly to evaluate key health outcomes for those with cancer and other chronic conditions. Yet there is a paucity of data linking neighborhood disadvantage to cancer clinical trial availability and access for the most socially vulnerable groups.
Shakira J. Grant, MBBS
Using multiple myeloma as an exemplar cancer subtype that disproportionately affects older adults (median age at diagnosis, 69 years) and results in the greatest Black-White survival disparities (death rate, 6 per 100,000 for Black persons vs 3 per 100,000 for White persons),3 we used the ClinicalTrials.gov database to investigate the association between the level of social vulnerability and available interventional multiple myeloma trials in North Carolina counties. In this cross-sectional analysis, reported in JCO Oncology Practice,4 we found that counties with the most affluent neighborhoods, compared with those that had high poverty rates, had six times the odds of having a registered clinical trial focused on multiple myeloma. These findings suggest the availability of clinical trials is not equitably accessible among populations with a disproportionate burden of social vulnerabilities.
Study Methodology and Results
We examined the characteristics of 229 multiple myeloma trials opened across 462 nonunique trial sites in North Carolina between 2002 and 2021. Social vulnerability was measured at the county level using the ZIP codes of each trial site linked to the Centers for Disease Control and Prevention Social Vulnerability Index. We examined clinical trial availability using logistic regression models, adjusting for metropolitan, suburban, or rural status.
Of the 100 North Carolina counties, 34 had registered trials during the study period, nearly 50% were conducted in academic medical centers, and 82% were industry-sponsored. The odds of having one or more registered multiple myeloma trial sites were six times greater (odds ratio [OR] = 5.60; 95% confidence interval [CI] = 1.85–19.64; P = .004) for the most affluent neighborhoods (low social vulnerability index score 0–0.333) as opposed to the poorest neighborhoods (higher social vulnerability index score 0.666–1). Counties with the lowest percentage of Black people, Indigenous people, and people of color as well as non-native English-speaking individuals had 77% lower odds (OR = 0.23; 95% CI = 0.07–0.7; P = .011) of having at least one multiple myeloma trial site than those with the highest percentage of these persons. After adjusting for metropolitan, suburban, or rural status, we found the lower odds of having one or more registered multiple myeloma trial sites remained statistically significant for counties with the lowest percentage of Black people, Indigenous people, and people of color as well as non-native English-speaking individuals (OR = 0.25; 95% CI = 0.07–0.81; P = .025) compared with those with the greatest percentage of these persons. Results were similar for sensitivity analyses conducted to account for the expected clustering of trial sites in the five counties with academic medical centers.
Our study highlights the influence of multiple population-level factors, including poverty and socioeconomic status, on the location of sites offering multiple myeloma trials accessible to the most socially vulnerable populations. Future studies should evaluate the associations between community-level social vulnerability and other cancer types beyond multiple myeloma, which would provide the foundation for developing and testing multilevel approaches to addressing racial or socioeconomic inequities in cancer clinical trial participation. Such approaches should target patient and provider knowledge and attitudes about clinical trials as well as organizational practices and policies that ensure equitable access to clinical trial participation.
Dr. Grant is a Geriatric-Hematologist-Oncologist and Assistant Professor–tenure track in the Division of Hematology at the University of North Carolina at Chapel Hill.
DISCLOSURE: Dr. Grant reported no conflicts of interest.
1. Agency for Toxic Substances and Disease Registry: CDC Social Vulnerability Index 2018 Documentation [North Carolina] Available at https://www.atsdr.cdc.gov/placeandhealth/svi/documentation/SVI_documentation_2018.html. Accessed on February 8, 2023.
2. Kind AJH, Buckingham WR: Making neighborhood-disadvantage metrics accessible: The Neighborhood Atlas. N Engl J Med 378:2456-2458, 2018.
3. Centers for Disease Control and Prevention: U.S. Cancer Statistics: Data Visualizations, based on 2021 submission data (1999–2019). Available at www.cdc.gov/cancer/dataviz. Accessed February 8, 2023.
4. Grant SJ, Jansen M, Kuo TM, et al: Cross-sectional analysis of clinical trial availability and North Carolina neighborhood social vulnerability. JCO Oncol Pract 6:OP2200325, 2022.