MD Anderson study also finds reduced toxicities with use of more advanced radiation therapy.
For patients with advanced, inoperable stage 3 lung cancer, concurrent chemotherapy and the specialized radiation treatment, proton therapy, offers improved survival compared to historical data for standard of care, according to a new study from The University of Texas MD Anderson Cancer Center.

The research, published in JAMA Oncology journal, reported an overall survival (OS) of 26.5 months. In contrast, the historical OS rate with standard of care concurrent chemotherapy and traditional radiation was 16 months at the time when the study was designed.

The findings are the final results of the single institution, Phase II study and represent the longest follow–up to date of stage 3 lung cancer patients who have received proton therapy, said Joe Y. Chang, MD, professor, Radiation Oncology and the study’s corresponding author.

“With our study, we hypothesized that proton therapy would offer a survival benefit to patients and reduce treatment–associated toxicities, which can be very serious,” he said.

The study opened at MD Anderson in 2006; in this research, Chang and his colleague report on the study’s five–year results.

For the prospective Phase II trial, 64 patients with inoperable, Stage III non–small–cell lung cancer were enrolled. The study’s primary endpoint was OS. The researchers hypothesized that the median OS would increase from historical data of 16 months on standard therapy to 24 months. Secondary endpoints included distant metastasis and local and regional recurrence rates. Toxic effects of treatment in both the acute and late settings also were analyzed.

Median follow up was 27.3 months for all patients, and 79.6 months for alive patients. At five years, the median OS was 26.5 months, and the corresponding five–year OS was 29 percent. Median progression–free survival was 12.9 months, with a five–year progression–free survival of 22 percent.

In sum, 39 patients experienced a relapse, with distant sites representing 62 percent of all recurrences. Local and regional recurrence rates were low, 16 percent and 14 percent, respectively.

Among the acute and late toxic effects diagnosed in patients were: esophagitis, pneumonitis and cardiac arrhythmia. Of note, said Chang, no patients developed the most severe, or grade five, toxicities, as seen in patients who receive standard of care.

Chang noted his study is not without limitations. Of greatest significance: the study was designed more than a decade ago. While the study’s survival, recurrence rates and toxic effects are still favorable when compared to rates associated with the most advanced traditional photon radiation therapy, intensity modulated radiation therapy (IMRT), technology to diagnose and stage the disease, as well all treatment modalities have significantly improved.

A Phase II trial studying IMPT and concurrent chemotherapy is underway.

Chang also noted the advancements in cancer biology and immunotherapy and that both are important areas of research focus in combination with proton therapy.