A medical center’s level of experience with intensity modulated radiation therapy (IMRT) can have a significant impact on the outcomes of mesothelioma patients who undergo the treatment. That conclusion comes from a new study conducted by cancer experts at Memorial Sloan-Kettering Cancer Center in New York and published in the International Journal of Radiation Oncology, Biology, Physics.
IMRT is a precision method for delivering radiation into a tumor while protecting healthy cells from overexposure. Controlled by a computerized device called a linear accelerator, IMRT delivers beams of radiation in short bursts which give it the ability to conform radiation dose to the shape of a tumor. This ability to accurately target even oddly-shaped tumors is the reason some believe IMRT can be a valuable part of mesothelioma treatment.
The New York study focused on the cases of 67 malignant pleural mesothelioma patients who underwent hemithoracic (on one side of the chest) IMRT between November 2004 and May 2013. Specifically, the team wanted to know when and where mesothelioma tumors began to grow again after treatment.
After a median follow-up of two years from diagnosis, doctors found that most (64%) mesothelioma tumors eventually began growing again at their original spot. Although this happened at a median of 10 months for all study participants, mesothelioma patients in the study who underwent a pleurectomy/decortication procedure prior to IMRT had a significantly longer time before their tumors regrew – a median of 14 months, versus just 6 months for patients who did not undergo P/D.
In 13 (19%) of the studied mesothelioma patients, cancer returned along the margins of the treatment area, just outside the area that received the highest IMRT dose. In these cases, especially, the researchers said experience appeared to make a difference in outcomes. “Increasing experience and improvement in target delineation minimize the incidence of avoidable marginal failures,” writes lead study author Andreas Rimner, MD.
Because mesothelioma is resistant to some degree to all conventional cancer treatments, most patients are treated with a combination of therapies which may include chemotherapy, radiotherapy, surgery and/or experimental treatments.
Rimner, A et al, “Failure Patterns After Hemithoracic Pleural Intensity Moducated Radiation Therapy for Malignant Pleural Mesothelioma”, July 26, 2014, International Journal of Radiation Oncology, Biology, Physics, Epub ahead of print