Japanese researchers are reminding doctors to watch for signs of peritoneal mesothelioma in people who have undergone past radiotherapy.
Many cancer patients undergo radiotherapy. Radiation disrupts the DNA inside cancer cells. This can help keep these malignant cells from replicating and spreading.
But radiation treatment also has a downside. It can cause cellular changes in healthy cells, too. This can cause side effects right away, or decades later.
As more people have radiation and survive, scientists at the Shinshu University School of Medicine say more of them could develop radiation-related mesothelioma later in life. But the signs of peritoneal mesothelioma years after radiation are easy to miss.
Peritoneal Mesothelioma Case Study
The new report is based on the case of a Japanese peritoneal mesothelioma patient. The 85-year-old patient underwent several surgeries for ovarian cancer. She also had radiation several times.
She came to the hospital with abdominal pain and diarrhea. But her doctors did not immediately think of these as signs of peritoneal mesothelioma.
The woman got sicker and sicker. She eventually died of cardiac arrest. It was not until her autopsy that doctors realized that her abdominal symptoms were signs of peritoneal mesothelioma.
Radiation and the Signs of Peritoneal Mesothelioma
Peritoneal mesothelioma is a malignancy that happens on the membrane lining the abdomen. This membrane encases the abdominal organs in fluid and prevents friction between them.
Like pleural mesothelioma, peritoneal mesothelioma is usually caused by exposure to asbestos. Scientists think microscopic asbestos fibers trigger changes in the DNA of peritoneal cells. The result is mesothelioma decades later.
In rare cases, radiation can have a similar effect on peritoneal cells. As with asbestos-triggered mesothelioma, it can take decades for the signs of peritoneal mesothelioma to develop after radiotherapy.
The Japanese team says they did not think of mesothelioma in the current case because the radiation happened so long ago. Normally, people show signs of peritoneal mesothelioma 10 to 30 years after radiotherapy.
“To the best of our knowledge, this is the first report of a patient with malignant mesothelioma developing ~50 years after radiotherapy,” writes lead study author Maki Ohya.
Recognizing Mesothelioma Symptoms in Radiotherapy Patients
The most common signs of peritoneal mesothelioma include:
- Feeling of Fullness
- Abdominal Swelling/Weight Loss
- Abdominal Fluid
- Loss of Appetite
As the disease progresses, it can also cause gastrointestinal symptoms like vomiting and diarrhea. Patients who have been exposed to asbestos should tell their healthcare provider. They should also be aware of the signs of peritoneal mesothelioma.
The authors of the Japanese case report say they hope their experience will remind cancer doctors that radiotherapy can also cause mesothelioma.
They advise, “Malignant mesothelioma should be considered in the differential diagnosis of patients with a history of radiotherapy who present with gastrointestinal symptoms.”
Ohya, M, et al, “Malignant peritoneal mesothelioma diagnosed 50 years post-radiotherapy for ovarian cancer in a patient with a history of multiple malignancies: An autopsy case”, August 2, 2019, Molecular and Clinical Oncology, pp. 396-400, https://doi.org/10.3892/mco.2019.1906