Black patients with malignant pleural mesothelioma typically live longer than white patients, despite being less likely to undergo aggressive surgery for the cancer caused by asbestos exposure.
The reason for the disparity remains unclear. Mesothelioma patients who have surgery normally survive longer than those who do not.
The study stems from the Surveillance, Epidemiology and End Results (SEER) Database across America from 1973 to 2009, which included 13,734 confirmed cases of mesothelioma.
They were reviewed recently by researchers in the department of thoracic surgery at Mount Sinai Medical Center and in the department of population health at Hofstra North Shore School of Medicine. Results were published earlier this year in Disease Markers, a peer reviewed open access journal.
"It's the largest series ever studied [in regard to race differences]," Mount Sinai thoracic surgeon and mesothelioma specialist Dr. Andrea Wolf told Asbestos.com. "And it sheds light on some differences that we need to look at more closely to help these patients."
The database of patients included 13,046 whites and 688 blacks. There was a stark contrast in incidence rates, which included 1.1 per 100,000 for whites but only 0.5 per 100,000 for blacks.
Higher Percentage of Black Females
Black patients were more likely to be younger and female, but also more likely to have advanced stage disease at time of diagnosis.
Among the specific findings:
- White patients had a mean survival of 15.5 months. Black patients had a mean survival of 16.7 months.
- 18 percent of black patients had aggressive surgery, compared to 24 percent of white patients.
- 7.9 percent of white patients not having surgery survived three years or more, and 3.5 percent reached the five-year mark.
- 10.6 percent of black patients not having surgery survived three years or more, and 6.7 percent reached the five-year mark.
- 22 percent of white patients were female, compared to 26 percent of black patients.
In a multivariable analysis, younger age, female gender, cancer-directed surgery and earlier diagnosis were predictors of longer survival in white patients. In black patients, only younger age and cancer-directed surgery translated into longer survival.
Lower Incidence May Be Traced to Occupational Opportunity
The authors surmise lower incidence of black mesothelioma patients could be related to lower opportunity for occupational exposure, which includes the U.S. Navy, which has a long history of high exposure rates.
They cite the U.S. Department of Labor statistics, which report black workers are less likely to be employed in specific occupations where high levels of asbestos were used in the past.
Researchers also speculate higher level of late-stage diagnosis for blacks could be related to lack of access to diagnosis procedures, general delays in seeking care for symptoms, or a lack of health insurance coverage that encourages earlier care. Early symptoms of mesothelioma could be different in black patients, too, the authors write.
Lack of Surgical Options
The lack of aggressive surgery for blacks with mesothelioma also could be directly related to their standard of care.
"Where you live, who [medically] you are seeing, the lack of developing a rapport with your doctor, the lack of access to a high-volume center, it could be a number of things," Wolf said. "We need to find out why, and how to help everyone."
There was an inverse trend, involving surgery with more advanced stage mesothelioma, with both ethnicities. With localized disease, 31.5 percent of whites and 29.3 percent of blacks had surgery. In advanced disease, 21.4 percent of whites and only 15.1 percent of blacks had surgery.
"This study suggests that further attention to the treatment of black patients is needed to determine if patient survival would be improved with better access to the same treatments as whites," the authors write. "Further studies on exposure history, access to care, type of medical and surgical treatment, and hospital characteristics in black patients with MPM are needed."