Fast Neutron Radiotherapy safe and effective for treatment of non-small cell lung cancer: Study

Scientists from the Barbara Ann Karmanos Cancer Institute and Wayne State University School of Medicine (WSU SOM) in Detroit are presenting two research studies that found the use of Fast Neutron Radiotherapy (FNRT) – a form of radiation that is about three times more powerful than typical photon radiotherapy – is highly effective and safe for patients who are dealing with non-small cell lung cancer. The findings are being formally presented Monday, Nov. 1, at the American Society of Therapeutic Radiology and Oncology (ASTRO) Annual Meeting.

George G. Chen, M.D., chief resident of Radiation Oncology at Karmanos and WSU SOM, is giving the poster presentations on the two research projects titled, "Salvage Fast Neutron Radiotherapy for Treatment of Refractory Non-Small Cell Lung Cancer" and "Fast Neutron Radiotherapy for Advanced Stage Non-Small Cell Lung Cancer."

Fellow authors are fourth-year medical student Laura Koller, as well as members of Karmanos and WSU SOM's Department of Radiation Oncology, including Peter Paximadis, M.D.; Professor Michael Joiner, Ph.D.; Jay Burmeister, Ph.D., chief of Physics; and Andre Konski, M.D. MBA, MA FACR, professor and chair of the Department of Radiology and clinical service chief of Radiation Therapy. Other authors from Karmanos are Shirish M. Gadgeel, M.D., leader, Thoracic Oncology Multidisciplinary Team; Antoinette Wozniak, M.D., member of the Thoracic Oncology Multidisciplinary Team; and Frank Baciewicz, M.D., professor of surgery.

Researchers analyzed results for non-small cell lung cancer patients that were treated at Karmanos from 1993 to 2006. Treatments included a combination of fast neutron and photon radiotherapy.  

"The main point of our research was to determine which patients could benefit from FNRT," said Dr. Chen. "We found we could deliver FNRT safely at certain dose levels, which we had to translate from fast neutron radiation doses to photon radiation doses."

Delivering FNRT takes great skill considering it comes with risks, Dr. Chen said, including potential for higher levels of toxicity. FNRT lost favor in the medical community in the past because in some cancer patient cases, delivering FNRT resulted in higher toxicities.

Researchers at Karmanos and WSU SOM said that it's critical to understand and use the most effective and safest doses to provide the best outcomes for patients who can benefit from both photon and neutron radiotherapies. While FNRT can help many cancers, it seems to work best on lung cancer, sarcomas, glioblastomas (brain cancers), prostate cancer and head and neck cancers.

In the FNRT study for salvage therapy, 20 patients with non-small cell lung cancer had failed primary treatment with chemotherapy and/or radiotherapy. The estimated clinical relative biological effectiveness for neutron radiotherapy was three times more effective than photon radiotherapy in the normal lung tissue and four times more effective for targeted tumors. In the study group, researchers found there were no grade three or four toxicities, which usually require significant medical intervention or hospitalization. All treatment related toxicities, such as radiation pneumonitis, esophagitis and radiation dermatitis were adequately treated in an outpatient basis.

Among the 12 patients who had longer than a one-month follow up, six patients had no evidence of local cancer progression. The median local control of the other six patients that did have cancer recurrence was three months. Nine out of the 14 symptomatic patients had successful palliation within a month after treatment was over. One year overall survival was 20 percent, and one year disease-free survival was 10 percent.

For the study of FNRT for advanced stage non-small cell lung cancer, Chen and his co-authors looked at the results of 23 patients who received a combination of FNRT and photon radiotherapy for non-small cell lung cancer between March 1993 and December 2006.

Median follow up was five months. There were no grade 4 toxicities recorded. Three patients had developed grade 3 radiation pneumonitis; 12 patients developed grade 1 or 2 esophagitis. Nine patients developed grade 1 radiation dermatitis and one patient had grade 3 radiation dermatitis. Among the 20 patients who had longer than a one-month follow up, 16 patients (80 percent) had no evidence of local progression, and the median local control of the other four who did recur was three months. Median overall survival was seven months, and median disease-free survival was almost three months. One year overall survival was 32.4 percent, and one-year disease free survival was 5.3 percent.

"We've found with these two studies that we can deliver FNRT safely," said Dr. Chen.