Promising results from the Groupe Européen de Curiethérapie European Society for Therapeutic Radiology and Oncology (GEC-ESTRO) trial, to evaluate the effects of partial breast irradiation (PBI) administered with multicatheter interstitial brachytherapy, were presented by co-lead author Dr. Csaba Polgár at the 35th European Society for Therapeutic Radiology and Oncology (ESTRO) Conference, Turin.
The new Phase III clinical data adds to the IMPORT-Low trial results, which together demonstrate the clinical equivalence of PBI and whole breast irradiation (WBI) for the treatment of early breast cancer.
Accelerated partial breast irradiation with brachytherapy (APBI brachytherapy) is a treatment composed of a short course of high-dose radiation therapy delivered directly into the tumor tissue of early-stage breast cancer patients. It is delivered as part of breast conservation therapy (BCT), which consists of lumpectomy surgery followed by radiation. Whole breast irradiation (WBI) has been the traditional approach of BCT, a procedure that exposes the entire breast and surrounding tissue to radiation. APBI offers three main advantages over WBI: reduction in radiation exposure, reduced treatment time and preservation of future organ sparing treatment options.
The primary objective of the GEC-ESTRO clinical trial was to compare APBI brachytherapy to WBI with boost, in a group of patients with invasive (stage I-IIA) breast cancer or ductal carcinoma in situ (DCIS; stage 0) who underwent breast-conserving surgery. The study evaluated 1,184 patients randomized to either group. Previous results, published in The Lancet, demonstrated that APBI brachytherapy had equal overall survival rate, disease-free survival rate and local cancer control compared to WBI with boost.
The new data refers to 969 patients (82% of the total enrolled patients). Five-year follow-up data indicates that the toxicity profile was similar between treatment arms, with fewer late skin side effects and better cosmetic results in the APBI group. No grade 4 toxicities were reported and significantly more patients experienced excellent cosmetic results after APBI when compared with WBI (43.6% vs 30.9%).
Dr. Vratislav Strnad, chair of the GEC-ESTRO Breast Cancer Working Group and a radiation oncologist at the Department of Radiation Oncology of University Hospital in Erlangen, Germany, said in a news release that the data will likely spark changes in how certain women with early breast cancer are treated.
“Early stage breast cancer has high unmet medical needs and places an enormous physical, emotional and economic burden on women, families and health care systems,” said Strnad. “We anticipate these data will drive significant changes in how clinicians approach early stage breast cancer treatment in patients 50 years and older and place APBI multicatheter brachytherapy as an accepted standard alternative to whole breast irradiation.”