The minimally invasive technique is called cryoablation or cryosurgery. Although it has been used in medicine for decades, UCLA is one of the few centers using cryoablation to treat mesothelioma tumors.
The Challenge of Treating Mesothelioma
Pleural mesothelioma, which grows on the membrane that surrounds the lungs, is challenging to treat for a number of reasons.
Mesothelioma causes few symptoms in its early stages so it is possible for it to grow unchecked until it is less likely to respond to treatment. When conventional treatments like chemotherapy or radiation are initiated, mesothelioma often does not respond the way other cancers do. It also frequently recurs after treatment.
In addition, mesothelioma tumors are irregular in shape and are located dangerously close to vital organs like the lungs, making them hard to remove surgically.
While a number of cancer centers use cryoablation to treat other types of tumors, few use the technique for malignant mesothelioma for fear of damaging the lungs.
Cryosurgery has been used to treat several types of cancer, including prostate, liver, breast, cervical and some types of skin cancer.
For the new UCLA study, 24 mesothelioma patients underwent 110 cryoablations for recurrent mesothelioma. Radiologists use CT to guide the placement of a hollow instrument into contact with the mesothelioma tumor and release a gas which kills cancer cells by freezing them.
“Freedom from local recurrence was observed in 100% of cases at 30 days, 92.5% at 6 months, 90.8% at 1 year, 87.3% at 2 years and 73.7% at 3 years,” reports lead author and UCLA radiologist Fereidoun Abtin, MD, who performs the procedure.
The results are particularly impressive given the fact that most patients diagnosed with mesothelioma die of the disease within a year of diagnosis, even with aggressive treatment.
Just as importantly, none of the mesothelioma patients in the study died from treatment-related side effects and only 7 percent had any significant complications.
Predicting Mesothelioma Tumor Recurrence
Unfortunately, cryoablation is still not a cure for mesothelioma. Mesothelioma tumors did recur eventually. However, one advantage of cryoablation over some other treatments is that it can be safely repeated.
When the researchers looked at the risk factors for mesothelioma tumor recurrence, they found that when there was a smaller margin between the edge of the frozen tumor and the surrounding healthy tissue, recurrence was more likely.
The research team team concludes their report summary in the Journal of Vascular and Interventional Radiology with these encouraging words: “CT-guided cryoablation is safe for local control of recurrent mesothelioma, with a low rate of complications and promising early-term efficacy.”
Abtin, F, et al, “Percutaneous cryoablation for the treatment of recurrent malignant pleural mesothelioma: safety, early-term efficacy, and predictors of local recurrence”, December 12, 2016, Journal of Vascular and Interventional Radiology, Epub ahead of print
“Cryosurgery in Cancer Treatment”, National Cancer Institute website, accessed December 18, 2016