Measuring tumor thickness may help doctors do a better job of determining which patients should have aggressive treatments for malignant pleural mesothelioma (MPM), research shows.
The multimodal therapy that is used to treat MPM today typically includes surgery, chemotherapy, and radiation. But surgery’s role has remained controversial because of what critics say is a faulty mesothelioma clinical staging system. The system makes it difficult to select patients who need aggressive treatment and hampers comparisons between surgical and non-surgical approaches, the critics contend.
Many doctors like an innovative approach called surgery for mesothelioma after radiation therapy, or SMART. It has proven better than induction chemotherapy — or chemo that is given before other treatments — at preventing mesothelioma from worsening, research has shown.
It has also been associated with promising results in patients with epithelial MPM. Epithelial cells are those that line body cavities.
Contradictory results in analyses of MPM samples have made it difficult to select appropriate patients for the SMART approach, however.
So researchers decided to evaluate whether tumor thickness could be used to refine the selection criteria of patients chosen for the SMART approach.
John Cho, MD, PhD, of the Princess Margaret Cancer Center, led the research team. The assistant professor at the University of Toronto is also with Toronto General Hospital.
Researchers looked for a connection between tumor thickness and MPM patient outcomes. They also looked at tumor volume and other parameters.
The team reviewed 65 MPM patients who had never been treated before and were now going through SMART. After a median follow-up of 19 months, the cancer had recurred in 40 patients, or 62%, while 36 of the patients, or 55%, had died.
Researchers found a correlation between tumor thickness — which ranged from 2.4 to 21 cm — and tumor volume, which research has shown to be a potential marker of MPM outcomes.
Importantly, tumor thickness was a predictor of overall survival and disease-free survival. Diaphragmatic tumor thickness offered the best correlation with survival, indicating that it could help determine the disease’s clinical stage.
Overall, “the impact of tumor thickness on survival and disease-free survival independent of histologic subtypes and nodal disease is extremely encouraging,” the researchers wrote. The study showed that “the SMART approach provides encouraging results in patients with epithelial subtypes,” compared with outcomes in other large multimodal prospective clinical trials.
The researchers suggested that tumor thickness “could potentially be used to refine the clinical staging of malignant pleural mesothelioma and optimize patient selection for radical treatment.”
Future studies are needed to confirm that tumor thickness is a good predictor of outcomes, the team said. Additional studies should include connections between tumor thickness and other treatment approaches, they said. And they should include more patients, the team added.