People who have radiotherapy to treat lymphoma are more likely to develop malignant mesothelioma, especially if they were diagnosed before 1995 and were younger at diagnosis, a study reports.
The research, “Therapeutic radiation for lymphoma: risk of malignant mesothelioma,” was published in the journal Cancer Causes & Control.
Radiotherapy has been used as a cancer treatment since the 1950s. But it doesn’t just kill cancer cells. It also triggers changes in healthy cells that can lead to other cancers.
A number of studies have reported an increased prevalence of mesothelioma among cancer survivors who had received radiation. The association was not found among cancer survivors who did not receive radiation.
Researchers at SRI Biosciences’ Center for Health Sciences in California examined records of Hodgkin and non-Hodgkin lymphoma survivors to assess their risk of developing mesothelioma after radiation therapy.
The team analyzed data from the U.S. National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) program. The records covered 47,219 Hodgkin and 252,090 non-Hodgkin patients diagnosed between 1973 and 2014.
“In this study, by far the largest study to date of mesothelioma risk after radiotherapy for lymphoma, we took advantage of the relatively large number of cases to conduct a multivariate adjusted survival analysis of the independent impact of radiotherapy” on mesothelioma risk, the researchers wrote.
Forty-one percent of those with Hodgkin lymphoma received radiation during their treatment course, versus 21 percent of non-Hodgkin lymphoma patients.
Twenty-eight, or 0.039 percent, of the patients who received radiotherapy developed malignant mesothelioma. Among those who did not receive radiation therapy, 59, or 0.026 percent, developed the disease.
After adjusting for age at lymphoma diagnosis, sex, race, lymphoma type, year of diagnosis, and lymph node status, the team found that survivors who had received radiation therapy were 64 percent more likely to develop mesothelioma.
This was particularly true of those who were less than 40 years old when diagnosed, and those whose cancer had been dormant at least 10 years. In addition, those diagnosed with lymphoma before 1995 were 2.6 times more likely to develop mesothelioma than those diagnosed after 1995.
Overall, the results showed that radiotherapy increases the risk of a lymphoma patient developing mesothelioma.
“Our results offer greater insight into how radiotherapy-induced mesothelioma varies by demographic and treatment characteristics, thereby shedding greater light on the epidemiology of this uncommon and lethal cancer,” they added.