Miner Study Finds Mesothelioma Often Undiagnosed

A new study of former South African mine workers suggests that too many asbestos-related diseases may be going undiagnosed.

The study conducted by researchers at the University of the Witwatersrand and the National Institute for Occupational Health in Johannesburg found that, in a cohort of 149 workers, more than half of the cases of malignant mesothelioma were missed until after the patient had died.

With cases of asbestos-related lung cancer, the difference between the number of cases identified by an autopsy and the number of cases actually diagnosed in the patient’s lifetime was even more dramatic – 22 identifications on autopsy versus just 3 lung cancer diagnoses.

Doctors diagnosed 52 cases of the lung-scarring disease asbestosis among the studied workers, but found 77 cases when their bodies were autopsied.

Mesothelioma Diagnosis Not Sensitive Enough

The researchers found that doctors were only able to correctly diagnose cases of malignant mesothelioma about 40 percent of the time. They were much better at being able to rule it out; current diagnostic tests correctly identified those who were mesothelioma-free in 97 percent of cases.

Asbestos-related lung cancer proved even more difficult to diagnose. Only 16.6 percent of lung cancer cases were correctly identified, but 100 percent of miners who did not have lung cancer were correctly ruled out.

Not surprisingly, false-negative diagnoses of asbestosis were more likely if the X-ray images were deemed to be just “acceptable” rather than “good” quality.

The study’s authors say these numbers point to the fact that asbestos diseases like pleural and peritoneal mesothelioma are challenging to diagnose and X-rays alone should not be used to rule out suspected cases.

“Where clinical features suggest asbestos-related diseases but the chest radiograph is negative, more sophisticated imaging techniques or immunohistochemistry for asbestos-related cancers should be used,” writes the study’s lead author, Ntombizodwa Ndlovu with the School of Public Health at the University of Witwatersrand.

Autopsy and Mesothelioma Compensation

While it is critical to improve identification and treatment of malignant mesothelioma and other asbestos diseases, Dr. Ndlovu and his colleagues say autopsies can still play a valuable role, especially in cases where an asbestos disease was suspected but never diagnosed.

In these cases, say the authors, autopsies can be used to monitor how good a clinical practice is at recognizing these diseases and at identifying cases where compensation may be warranted.

Most cases of asbestos-related diseases, including both pleural and peritoneal mesothelioma, are caused by exposure to asbestos in the workplace. Often this happens because an employer failed to adequately protect or train workers, such a miners, who were likely to come in contact with toxic asbestos.

Source:

Ndlovu, N, et al, “Asbestos-related diseases in mineworkers: a clinicopathological study”, August 25, 2017, ERJ Open Research, eCollection