Proton Therapy Helps Eradicate Recurrent Lung Cancer

A new study reports that using intensity-modulated proton therapy (IMPT) for recurrent lung and other thoracic tumors could offer a new treatment option for patients who previously had none.

The study, by researchers at the University of Texas MD Anderson Cancer Center, retrospectively examined the records of 27 patients who received reirradiation for thoracic tumors using the IMPT technique through prospective clinical trials between 2011 and 2016; 81% had non-small cell lung cancer (NSCLC), and all patients had previously received curative thoracic radiation therapy (RT). Median time to reirradiation was 29.5 months, with a median follow-up for all patients of 11.2 months.

The results showed that median overall survival was 18 months following IMPT reirradiation. At one year, the majority of patients were free from local and regional relapse, and over half of the patients free from disease progression. Patients who received IMPT re-irradiation doses higher than population median were twice as likely to be free from local failure, and nearly four times as likely to be free from local-regional failure. Reirradiation with IMPT was well tolerated, with only two patients experiencing long-term lung toxicity. The study was presented at the 2017 Multidisciplinary Thoracic Cancers Symposium, held during March 2017 in San Diego (CA, USA).

“Treating patients who have already received a prior course of thoracic radiation is a common clinical scenario, and it is particularly challenging to subsequently provide strong enough radiation doses to eliminate the new tumor without causing significant harm to normal tissues,” said lead author Jennifer Ho, MD. “Our study is the first to show that IMPT can be safe and effective for these patients, and that it offers these patients a chance for lasting cancer control without adding significant toxicity.”

“We knew that IMPT would allow us to generate much more precise radiation treatment plans that spared normal tissue, but we weren’t sure if this would translate into excellent clinical outcomes,” said senior author professor of radiation oncology Joe Chang, MD. “Our findings demonstrate that the use of IMPT resulted in better local control and survival, with very minimal toxicity compared to other radiation types, suggesting that IMPT is the optimal treatment modality for re-treatment of thoracic cancers.”

Proton therapy is a precise form of RT that uses charged particles instead of x-rays. It can be a more effective form of treatment than conventional radiotherapy as it is more precise, with minimal damage to surrounding tissue. Evidence is growing that protons can be effective in treating a number of cancers, in particular in children and young people with brain tumors, for whom it appears to produce fewer side effects such as secondary cancers, growth deformity, hearing loss, and learning difficulties.