Proton beam therapy provides disease control, cuts side effects in early breast cancer

After initial clinical trial results showing excellent disease control, Loma Linda University Medical Center (LLUMC) has expanded enrollment in a breast cancer trial of proton beam radiotherapy.

Results of the Phase II clinical trial conducted by researchers at the LLUMC department of radiation medicine have indicated that partial breast radiotherapy delivered with proton beams appears to provide excellent disease control within the breast with minimal risk of side effects, according to a press release. Apart from being less toxic to the patient, the technique reduces radiation treatment time to two weeks instead of seven weeks.

The disease-free survival rate at five years for the initial 50 patients who took part in the study was 92 percent, while the overall survival rate was 96 percent. The study results were initially presented at the American Society for Radiation Oncology meeting in 2010, and were published in Clinical Breast Cancer in August 2011.

“The study results show that we are able to offer early stage breast cancer patients a treatment program that is less risky and can be completed in less time,” said David Bush, MD, vice-chairman of the department of radiation, said in the release.

The study looked at treatment results provided by targeting proton beam radiation to the area where the tumor was located instead of the whole breast. The breast cancer clinical trial investigated the safety and efficacy of utilizing proton beam radiotherapy to deliver partial breast radiotherapy following lumpectomy for early stage breast cancer.

Initially, 50 patients who had invasive (non-lobular) carcinoma and had undergone a lumpectomy were enrolled in the clinical trial. The patients had primary tumors that were three cm or less and the cancer had not yet metastasized. They received daily proton beam treatment over a two-week course.

The study completed enrollment of 100 patients, and the second phase of the trial will add an additional 100 patients. The study, which began in 2004, has been expanded to include slightly more advanced tumors.