Treatment outcomes for patients with malignant pleural mesothelioma (MPM), a rare cancer commonly known as mesothelioma, are often affected by social determinants of health (SDOH) and overall survival (OS) rates could be improved by addressing these health disparities and improving access to specialized care.

That’s the key takeaway from a study, supported by the Geographic Management of Cancer Health Disparities Programs (GMaP) Region 2 Trainee/Early-Stage Investigator Research Reimbursement, and published on March 23, 2023 by investigators at the Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine and collaborators, whose study appears in the journal JAMA Network Open. [1]

“We found that mesothelioma patients who receive treatment in a timely fashion – and have access to specialized care, including surgery, radiation therapy and chemotherapy – have better outcomes,” noted oncologic surgeon Estelamari Rodriguez, M.D., M.P.H., associate director of community outreach in thoracic oncology and senior author on the paper.

“Unfortunately, many patients have poor access due to health disparities and geographical factors,” Rodriguez added.

Mesothelioma cases are rare in both the U.S. and globally, representing only 0.17 % or about 3,000 of all U.S. tumor diagnoses in 2018, the authors noted. That percentage is expected to decline further with greater awareness of the risks posed by asbestos exposure. [2].

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“We found that mesothelioma patients who receive treatment in a timely fashion – and have access to specialized care, including surgery, radiation therapy and chemotherapy – have better outcomes,” explained Estelamari Rodriguez, MD, MPH, Associate Director of Community Outreach; Breast Medical Oncology, Medical Oncology, Thoracic Medical Oncology. Photo courtesy: © 2023 Sylvester Comprehensive Cancer Center. Used with permission.

The latest guidelines suggest that multimodality therapy, including surgery, chemotherapy, and possible radiation therapy, may lead to the best possible overall survival outcomes for patients diagnosed with this rare tumor type. [3]

Unfortunately, many physicians have little or no experience treating mesothelioma, and those with specialized training and expertise often work at academic or other major medical centers clustered in the Northeast, South or on the West Coast. That leaves large parts of the United States underserved.

For this study, Rodriguez and colleagues performed a retrospective analysis of 1,389 patients from a 2017 National Cancer Database registry who were determined to have operable mesothelioma. The median age of participants was 66 [61-70], with 1024 [74%] being male, 1233 [89%] being White and the remaining ethnicity as follows: Asian 12 [1%], Black 49 [3%], Hispanic 74 [5%] and 21 [2%] of an other race. Median overall survival was 1.7 years ((95% CI, 1.6-1.8).

Among the key findings was that surgery in addition to systemic chemotherapy (HR, 0.70; 95% CI, 0.61-0.81) was independently associated with improved overall survival. But, unfortunately, the authors noted that many patients were never referred for surgery, perhaps due to clinicians being unawareness of treatment options, and as a result, biasing them toward palliative care.

“If a patient gets diagnosed with non-cell lung cancer, they will probably have access to surgeons near them who feel comfortable performing that surgery,” Rodriguez said.

“But oncologists in most communities have little experience with mesothelioma. This study showed that people can benefit from surgery and early multimodal treatment, but resources in the U.S. are not equally distributed,” she added.

Other factors associated with greater survival were recent treatment, treatment at high-volume academic hospitals and greater distance to travel for treatment between the patient’s residence and the hospital (HR, 0.92; 95% CI, 0.86-0.98). [4] These risk factors were associated with worse overall survival, according to the study, included older age, male sex (HR, 1.60; 95% CI, 1.38-1.86) and black race (HR, 1.96; 95% CI, 1.43-2.69).

In addition, the Social Determinants of Health (SDOHs) in this study included zip code–level median income (<100% federal poverty level [FPL], 100%-150% FPL, or >150% FPL based on the neighborhood of patient residence derived from 2016 US Census data), metropolitan statistical area (metropolitan, urban, or rural), and educational attainment (based on a percentage of individuals holding high school degrees according to zip code).

“This is where social determinants of health, including age, gender, race and income, may play a vital role in how patients are treated and explain some of the outcomes from our study,” said Rodriguez.

“There is no clear link between ethnicity and the risk of mesothelioma, but there are many things about living in communities with limited access to high-level care that can explain these differences,” noted Rodriguez.

Reducing outcome disparities
Sylvester continues striving to reduce outcome disparities among mesothelioma patients. In late 2021, the center held its inaugural Miami International Mesothelioma Symposium, a virtual conference designed to educate both providers and patients about this disease. A second conference is planned for November.

Additionally, Sylvester’s expert teams are reaching out to South Florida communities to educate them about the center’s mesothelioma program and its available resources, including clinical trials, immunotherapy and other treatment options.

“We need to get past the point where physicians tell their mesothelioma patients there’s nothing they can do for them,” Rodriguez explained.

“We know that patients who receive comprehensive care have better outcomes. It’s our job to make sure everyone has access,” Rodriguez concluded.

Note: * In this study, the closest travel times were estimated using a network analysis of the road distance weighted by travel speeds from the population or geographic centroid of every ZIP area in the continental U.S. to that of the nearest cancer care setting under consideration: National Cancer Institute (NCI)-designated Cancer Centers, academic medical centers, and oncologists.

[1] Alnajar A, Kareff SA, Razi SS, Rao JS, De Lima Lopes G, Nguyen DM, Villamizar N, Rodriguez E. Disparities in Survival Due to Social Determinants of Health and Access to Treatment in US Patients With Operable Malignant Pleural Mesothelioma. JAMA Netw Open. 2023 Mar 1;6(3):e234261. doi: 10.1001/jamanetworkopen.2023.4261. PMID: 36951862.
[2] Espinoza-Mercado F, Borgella JD, Berz D, Alban RF, Sarkissian A, Imai HTA, Soukiasian HJ. Disparities in Compliance With National Guidelines for the Treatment of Malignant Pleural Mesothelioma. Ann Thorac Surg. 2019 Sep;108(3):889-896. doi: 10.1016/j.athoracsur.2019.03.052. Epub 2019 Apr 18. PMID: 31004585.
[3] Alpert N, van Gerwen M, Steinberg M, Ohri N, Flores R, Taioli E. Racial Disparities in Treatment Patterns and Survival Among Surgically Treated Malignant Pleural Mesothelioma Patients. J Immigr Minor Health. 2020 Dec;22(6):1163-1171. doi: 10.1007/s10903-020-01038-x. PMID: 32529589; PMCID: PMC7686121.
[4] Onega T, Duell EJ, Shi X, Wang D, Demidenko E, Goodman D. Geographic access to cancer care in the U.S. Cancer. 2008 Feb 15;112(4):909-18. doi: 10.1002/cncr.23229. PMID: 18189295.

Featured image by National Cancer Institute on Unsplash

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