Race and Medicine
Race and Medicine
Source/Disclosures
Source:

Iorgulescu JB, et al. Abstract PO-091. Presented at: American Association for Cancer Research Virtual Meeting: The Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Oct. 2-4, 2020.

Disclosures: Iorgulescu reports no relevant financial disclosures. Please see the abstract for all other researchers’ relevant financial disclosures.
October 05, 2020
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Study shows disparities in access to molecular diagnostics for colorectal cancer

Source/Disclosures
Source:

Iorgulescu JB, et al. Abstract PO-091. Presented at: American Association for Cancer Research Virtual Meeting: The Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Oct. 2-4, 2020.

Disclosures: Iorgulescu reports no relevant financial disclosures. Please see the abstract for all other researchers’ relevant financial disclosures.
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Although testing for microsatellite instability and mismatch repair deficiency has increased for advanced colorectal cancer, substantial gaps in testing remain among certain patient groups, according to study results.

The results, presented at American Association for Cancer Research Conference on The Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved, showed testing occurred less frequently among older patients, those in historically underrepresented groups, and among uninsured or Medicaid-insured patients.

infographic showing rates of MSI and MMR testing among patients with advanced colorectal cancer

“The development of molecular diagnostics has helped to transform modern oncology, with the number of new FDA-approved molecularly targeted therapies growing each month. For example, detection of high DNA microsatellite instability [MSI] and mismatch repair deficiency [MMR] has become an important indication for use of immune checkpoint inhibitors in patients with advanced colorectal cancer,” Julian Bryan Iorgulescu, MD, FACP, instructor in the department of pathology at Brigham and Women’s Hospital, told Healio. “However, although there has been a lot of recent health services research on the disparities that cancer patients face in accessing standard-of-care therapies, there has been comparably very little research into whether there are disparities in access to molecular diagnostic testing.”

Investigators used the National Cancer Database to pool data on 45,326 patients newly diagnosed with histopathologically confirmed advanced colorectal cancer between 2010 and 2016. Patients who lacked data about MSI and MMR testing or who were initially diagnosed at another institution were excluded.

Julian Bryan Iorgulescu, MD, FACP
Julian Bryan Iorgulescu

Receiving MSI and MMR testing via immunohistochemistry or molecular diagnostic served as primary endpoints.

Researchers used multivariable logistic regression to evaluate the association between MSI and MMR testing and patient demographic, socioeconomic and care setting characteristics, as well as with receipt of immunotherapy.

Results showed 26.5% of patients (n= 11,998) underwent MSI and MMR testing. The rates of testing increased from 14.4% in 2010 to 41.1% in 2016 (adjusted OR per year = 1.26; 95% CI, 1.25-1.29).

Older age was significantly associated with a lower likelihood to undergo testing (age 70-79 years vs. 60-69 years, adjusted OR [aOR] = 0.83; 95% CI, 0.77-0.89; age 50-59 years, aOR = 1.25; 95% CI, 1.16-1.33). Testing also appeared less common among men (aOR = 0.94; 95% CI, 0.9-0.99) and Blacks compared with whites (aOR = 0.87; 95% CI, 0.82-0.94).

Moreover, testing was less common among patients who were uninsured (aOR = 0.78; 95% CI, 0.7-0.86), Medicaid-insured (aOR = 0.87; 95% CI, 0.8-0.94) and Medicare-insured (aOR = 0.87; 95% CI, 0.81-0.93) compared with privately insured, as well as among those diagnosed at a community (aOR = 0.6; 95% CI, 0.56-0.66) or comprehensive community cancer program (aOR = 0.76; 95% CI, 0.72-0.8) compared with those diagnosed at an academic or NCI comprehensive cancer program.

Of note, among patients diagnosed in 2016, those who were not tested also were less likely to receive immunotherapy (aOR = 0.61; 95% CI, 0.53-0.68).

“The magnitudes of some of the gaps in guideline-recommended MSI and MMR testing were quite surprising to us, but we are finding that many of the same socioeconomic factors associated with disparities in patients’ access to treatment and high-quality care are also associated with disparities in access to molecular testing,” Iorgulescu said.

“National cancer databases, like the one we used for our research, have been indispensable resources for identifying many of the disparities in health care for cancer patients,” Iorgulescu added. “Still, much more research is needed to convert what we are learning from national data into effective strategies for reducing those disparities. For our projects, that means finding ways to improve cancer patients’ access to critical molecular diagnostics.”