Researchers identified another tool for diagnosing pleural mesothelioma, hoping it can accelerate the diagnostic process and help eliminate recurring mistakes.
Dr. Michele Carbone of the University of Hawaii Cancer Center and his team of mesothelioma specialists discovered that tumor-suppressing protein BAP1 can help oncologists accurately differentiate mesothelioma from lung cancer.
People lacking the BAP1 protein are more likely to develop malignant mesothelioma.
In the team's study, all 45 non-small cell lung cancer samples tested positive for normal BAP1 expression. Of the 35 pleural mesothelioma samples tested, more than half didn't show BAP1.
“Now we have an additional tool that we can use to increase the accuracy of a diagnosis,” Carbone told Asbestos.com. “The fact is today there is a high rate of misdiagnosis. And there are many reasons for that. We need to use this tool to help get it right.”
His research team included specialists from New York University's Langone Medical Center and the Queen's Medical Center in Honolulu.
Rise in Misdiagnoses
“We still don't know for sure how many cases are being misdiagnosed in the United States, but 10 percent is a safe bet,” Carbone said. “That means there are lots of people not receiving the proper treatment. It's important to increase the accuracy of the diagnostic process because the last thing you want as a patient is to be treated for the wrong disease.”
By comparison, an estimated 200,000 people are diagnosed annually with lung cancer. The treatments, clinical trials and prognoses of mesothelioma are considerably different for lung cancer.
Pleural mesothelioma is a rare and aggressive cancer that starts in the thin membrane surrounding the thoracic cavity, but it often metastasizes to the lungs. There are an estimated 3,000 cases identified annually in the country, and many oncologists rarely see the disease.
Symptoms mirror those of lung cancer, too.
A precise diagnosis can be difficult to obtain outside of a speciality center.
“Many times the diagnosis [of mesothelioma] is simple, obvious and clear cut. Everything works like you expect. Other times, it is not clear cut at all, and that's when it becomes complicated,” Carbone said. “Patients need to know if the diagnosis is made with great confidence or by a 51 percent to 49 percent margin.”
Reasons for a Misdiagnosis
The inability to diagnose mesothelioma in the early stage of the cancer is one reason why the prognosis is often grim (6-18 months) and the treatment options limited. Patients are encouraged to find a mesothelioma specialty center that incorporates a multidisciplinary approach to treatment.
There are many reasons for a misdiagnosis:
- Inadequate, small specimen
- Misguided needle biopsy
- Pathologist inexperienced in mesothelioma
- Restrictions from insurance companies
Carbone believes the diagnostic accuracy of immunohistochemistry (IHC) staining for mesothelioma would be better if BAP1 were included in the panel. IHC staining distinguishes mesothelioma from lung cancer.
“Patients tend to believe that if a doctor says so, it is so. But for a diagnosis like this, you better be sure,” Carbone told Asbestos.com. “Before somebody takes your lung out, you want to know exactly what you have.”