Partial Breast Irradiation

In the past, women with breast cancer received mastectomies. Women with earlier stage disease received lumpectomy followed by whole breast radiation; roughly equivalent to mastectomy in terms of local control and overall survival. Whole breast radiation requires daily, Monday through Friday treatments for approximately 5 to 7 weeks, after chemotherapy, if needed.

Treating less than the whole breast is called accelerated partial breast irradiation (APBI) and targets just the area of breast tissue where the tumor was removed. By treating a smaller volume of tissue, we can deliver a larger dose of radiation during each treatment. Most APBI techniques involve giving radiation twice a day for five days shortly after surgery and before chemotherapy, if needed. Because this technique was somewhat difficult for doctors, patients and physicists (those who help doctors plan radiation treatment), other techniques were investigated.

The results from these early trials have created a lot of interest in partial breast irradiation and a large national trial is currently underway (run by NSABP and RTOG cooperative groups) to compare whole breast radiation and partial breast radiation head-to-head. This trial is open to women 18 years and older with tumors 3cm or smaller with negative margins. This trial also allows delivering partial breast treatment using 3D conformal external beam radiation for patients who cannot have a catheter/catheters placed due to location or due to patient/doctor preference.

The trial has already enrolled all the needed patients in the lowest risk groups and follow-up data is being collected. The results of this study will help doctors decide who can safely be treated with partial breast radiation. The physicians of Radiation Oncology Consultants have been treating patients with partial breast irradiation since April 2003 including treating patients on the current NSABP national trial.