There could be some good news for patients dealing with recurrent lung cancer. One type of radiation treatment, called intensity modulated proton therapy (IMPT), has shown promise in preliminary testing. Researchers at The University of Texas MD Anderson Cancer Center treated patients by reirradiating with IMPT. The majority of those patients had no cancer recurrence within one year of treatment. In addition, few people were subjected to side effects. The data from the research was reported at the 2017 Multidisciplinary Thoracic Cancers Symposium.
Lung cancer is a devastating disease, and recurrence is the main reason that people die. The American Cancer Society estimates that 155,870 die from the disease annually, while 222,500 people are newly diagnosed. Currently, none of the typical treatment options are very good and it is often not a condition that surgery can alleviate. Jennifer Ho, M.D., resident, Radiation Oncology explained that because the treatment options are poor, there is interest in using radiation as a therapeutic.
"Historically, repeat radiation at a higher, curative dose was not possible with older, less precise radiation techniques because the cumulative radiation dose necessary to treat the cancer would cause too much toxicity," explained lead author of the work, Ho. "In lung cancer, tumors are close to the esophagus, aorta and spinal cord, and all of these critical structures are vital for the body to function. The proton beam - and pencil beam in particular - provides much more conformal radiation, which means higher doses to tumors and lower dosages to critical structures nearby."
IMPT is one of the most advanced proton therapies, using scanning beam technology as a foundation to both optimize intensities and energies of all pencil beams to send a targeted dose of protons to tumors, explained Joe Y. Chang, M.D., Ph.D., a Professor of Radiation Oncology. "The technology has the ability to destroy cancer cells while sparing surrounding healthy tissue from damage. Therefore, important quality of life outcomes can be preserved and severe toxicities have shown to be reduced," said Chang, the corresponding author of the report.
While it was a relatively small study which employed a retrospective analysis, the investigators learned that of 27 patients given IMPT to treat lung cancer recurrence, after one year, 61 percent of the patients did not have a recurrence in the chest and lung. The researchers also found that those that received higher doses of radiation had fewer local recurrences and better progression-free survival. The radiation therapy was also tolerated well by the patients.
"With the advancement of IMPT, we knew that we were able to generate more precise radiation treatment plans that spared normal tissue, but we weren't sure if this would translate into beneficial clinical outcomes until we analyzed this data," said Chang. "While the findings are early, we're hopeful that we can offer more positive outcomes and low toxicity with IMPT for recurrent thoracic cancer patients who previously had few treatment options."
You can learn more about IMPT in the video, from MD Anderson Proton Therapy Center.