A new report from the National Cancer Institute (NCI) shows between 20 and 30 percent of malignant mesothelioma patients do not receive any cancer treatment.
The study, “Patterns of care and survival among patients with malignant mesothelioma in the United States,” published August 10 in the journal Lung Cancer, aimed to describe the patterns of care and subsequent survival among mesothelioma patients in the U.S. while adjusting for patient demographics and pre-existing health conditions.
Using the NCI’s Surveillance, Epidemiology, and End Results (SEER) data, researchers discovered significant differences in treatment patterns and overall survival between pleural mesothelioma patients and nonpleural patients.
Mesothelioma patients diagnosed with the pleural type and older than 70 were less likely to receive therapy compared to peritoneal mesothelioma patients and those diagnosed at younger ages.
Key findings included:
“These findings indicate the need for efforts to ensure equitable application of currently available therapies to all patients,” lead author Lindsey Enewold wrote in the study.
For many years, the combination of surgery, chemotherapy and radiation therapy has been the standard of care for mesothelioma.
This latest study gave new insight into the number of patients who undergo surgery, chemotherapy or radiation.
Systemic therapies — which includes chemotherapy and immunotherapy — was the most widely performed treatment for all types of mesothelioma, with around 62 percent of patients receiving some form of drug to treat cancer cells.
More pleural mesothelioma patients (18.4 percent) received radiation therapy than nonpleural patients (4.9 percent). This is likely because radiation therapy is limited for those with peritoneal mesothelioma, the second-most-common disease type, because it affects the lining of the abdominal cavity where radiation is commonly restricted.
However, peritoneal mesothelioma patients are more likely to undergo surgery. Only 27.1 percent of pleural patients underwent surgery, while 51.8 percent of nonpleural patients had at least one procedure.
A combination of cytoreduction surgery and heated chemotherapy has become the standard treatment option for peritoneal mesothelioma. Studies show half of patients who receive the procedure survive at least five years after diagnosis.
Heated chemotherapy isn’t as viable of an option for pleural patients, but some mesothelioma specialists have found success with intraoperative heated chemotherapy, which adds a chemotherapy solution to the thoracic cavity directly following surgery. The solution is then circulated throughout the cavity for up to an hour before it is drained.
Enewold and her team noted that new treatments for mesothelioma are being developed, but currently available therapies remain underutilized.
Emerging therapies, such as immunotherapy, continue to be a popular topic in the mesothelioma community.
Immunotherapy drugs including pembrolizumab (Keytruda) and nivolumab (Opdivo) still don’t have approval from the U.S. Food and Drug Administration (FDA) for the treatment of mesothelioma, but recent FDA approvals for non-small cell lung cancer are a step in the right direction for making immunotherapy a first-line treatment option for the asbestos-related cancer.
The drugs, which belong to a class known as checkpoint inhibitors, can be used in combination with other treatments or on their own for patients who may be ineligible for surgery or when chemotherapy is no longer effective.
Keytruda and Opdivo are available to mesothelioma patients through clinical trials and from doctors and oncologists who prescribe the drugs as an off-label use.
However, the NCI report shows clinical trial participation is very low for mesothelioma patients. According to the study, around 5 percent of pleural patients participated in a trial, while less than 2 percent of peritoneal patients enrolled.
Multivariate analysis from the study showed that systemic therapy improved overall survival regardless of treatment regimen or whether surgery was used. This demonstrates the need for more patients to enroll in clinical trials and the potential impact immunotherapy and other emerging therapies can have on treating mesothelioma and other aggressive cancers.
“Receipt of either surgery or systemic therapy and particularly the combination of these two modalities was associated with better all-cause survival,” Enewold wrote.