Clinical research from one of the country’s premier proton therapy research facilities shows that breast cancer proton therapy treatment results in excellent survival rates and cosmetic outcomes.
Loma Linda University conducted the clinical trial on patients with early stage invasive (non lobular) breast cancer. Results of the study of partial breast radiation therapy with protons were published in the International Journal of Radiation Oncology • Biology • Physics. This study represents a solid data set on the clinical benefits of proton therapy and breast cancer outcomes.
The phase-two clinical trial followed 100 breast cancer proton therapy patients, monitoring them for an average of five years following treatment. Results show that the in-breast recurrence-free survival rate was 97 percent with minimal side effects to the breast, lungs, and heart. The cosmetic results as assessed by patients and physicians were good to excellent in 90 percent of cases, which was maintained throughout the five years of follow-up.
Previously published studies indicate that good cosmetic results with photon radiation treatment diminish over time, likely due to increased scarring of the breast that occurs as a result of increased exposure of normal breast tissues when traditional photon radiation is used.
A traditional treatment plan for most women diagnosed early with breast cancer includes surgery to remove the tumor, followed by photon radiation treatment performed over the entire breast. However, the Loma Linda study looked at treatment results from using highly-targeted proton beam radiation isolated to the specific area of the tumor. With proton therapy, the size of the area impacted by radiation is reduced significantly, lessening exposure to the heart, lungs, and other parts of the body.
The study began in 2004 with initial results presented at the American Society for Radiation Oncology meeting in 2010. These results were published in the peer-reviewed scientific journal Clinical Breast Cancer in August 2011.
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 carcinoma and had undergone a lumpectomy were enrolled in the clinical trial, with 50 more being treated after initial analysis. The patients had invasive breast cancer with primary tumors that were three centimeters or less and the cancer had not metastasized. During treatment the patients were placed in a prone position in a patented, customized foam mold to improve the precision of the treatment. Proton treatment was given in 10 sessions over a two-week course. All showed excellent results.