One of the primary treatments for pleural mesothelioma is radiation therapy. Often used as an adjuvant therapy (i.e., as a secondary treatment after surgery and/or chemotherapy), radiation helps reduce the size tumors in the chest and can alleviate pain. However, radiation cannot distinguish between cancerous cells and noncancerous cells, which means that it can damage healthy tissue – sometimes significantly.

The good news is that there exists a special kind of radiation therapy called intensity modulated radiotherapy (IMRT) that uses small radiation beams and a more intense and targeted approach than standard techniques. Specifically, IMRT targets precise locations at the lining of the lungs, which helps to reduce the effects of radiation in other areas of the chest.

Radiation Therapy and Mesothelioma

A recent study has demonstrated some success when using IMRT on patients who undergo an extrapleural pneumonectomy (EPP) – a surgery that removes an entire lung and surrounding tissue in an attempt to get rid of cancer tumors. In particular, post-EPP patients had tumors that were controlled controlled after 9 months of IMRT treatment.

Up until now, the use of radiation therapy to treat mesothelioma has been somewhat controversial. Some experts have questioned the treatment’s efficacy, believing that it is not extremely effective in shrinking tumors. A bigger concern has been the potential for developing radiation pneumonitis, a condition that causes inflammation on the chest after several months of radiation therapy and can lead to fibrosis of the lungs – which may ultimately lead to fatal respiratory failure.

New studies like the one using IMRT are important to help doctors and researchers understand the mechanisms of potential new treatments, and developing new techniques that are more effective, better targeted, and less invasive than existing mesothelioma treatment options.

IMPRINTing New Treatments

To answer these two questions of efficacy and safety, the researchers at Memorial Sloan Kettering Cancer Center in New York and MD Anderson Cancer Center in Houston, Texas, conducted a study into the potential role of hemithoracic intensity-modulated pleural radiation therapy (IMPRINT) after chemotherapy and pleurectomy-decortication (PD). The latter is a less invasive surgical option as it only removes the diseased tissue and membranes, and preserves as much of lung as possible.

The total number of patients enrolled for the IMPRINT treatment was 45, out of which 9 had already progressed to a point where treatment was not feasible, 5 refused to take this treatment option, 2 chose EPP as a surgical option, and 2 developed complications when given chemotherapy.

During the trial, patients were given up to four cycles of chemotherapy with pemetrexed and a platinum agent (cisplatin is the most common), followed by the surgical treatment. After the chemotherapy courses, patients received a dose of IMPRINT radiation therapy.

All in all, the results offer some hope for using IMPRINT as a treatment option that can spare the lungs of mesothelioma patients. The average rate of survival without metastasis (spreading) was around 12.4 months, while the overall average survival rate of patients was seen just short of two years. With tumors that could be removed, the patients had two-year survival rate of 59%, and for patients with non-removable tumors, the rate stood at 25%. These are all better rates of survival than current treatment options offer.

Moving Forward with Lung-Sparing Treatments

The use of IMPRINT radiation after chemotherapy is a good news for patients suffering from mesothelioma, due to its relative safety and improved survival rate. It offers hope to mesothelioma patients, who generally have a poor prognosis, and researchers can continue to study the technique, hopefully improving on its effectiveness. While it may have a long way to go before being adopted as a standard form of treatment, it nonetheless gives mesothelioma patients and doctors a new tool to use in the fight against this deadly disease.