After a lumpectomy (removal of breast tumor), breast cancer patients usually have radiation therapy to kill any remaining cancer cells. There are two main types of radiation therapy — one that treats the whole breast and one that treats part of the breast. Which is more effective?
A long-term follow-up study discovered very little difference in the outcomes of women who received whole breast irradiation and those who had partial breast irradiation.
The different treatments resulted in similar rates of cancer return, disease-free survival and cancers developing in the other breast.
Jessica Wobb, MD, a radiation oncologist with the Beaumont Cancer Institute in Royal Oak, MI was the lead investigator of this study.
The goal of the study was to compare the clinical outcomes of patients who received whole breast irradiation (WBI) with those who had accelerated partial breast irradiation (APBI).
Whole breast irradiation involves beaming powerful X-rays to the outside of the entire breast from which a cancerous tumor was removed. The normal course of WBI requires sessions five days a week for five to six weeks.
Accelerated partial breast irradiation involves inserting a radioactive “seed” into the cavity where the tumor was removed. A device that holds the seed, which may be a balloon or stent, remains in place for eight to 10 days. This procedure is also known as brachytherapy.
This study followed 3,009 patients with early stage breast cancer who had a lumpectomy between 1980 and 2012. Of these women, 2,528 received WBI and 481 had been treated with APBI.
To compare the effectiveness of both techniques, participants who had received the different radiation therapies were matched according to age (within three years), cancer stage and estrogen receptor status (whether or not the cancers were driven by estrogen).
Women who had WBI were followed for an average of 8.1 years, and women who had APBI were followed for 7.8 years.
The researchers learned that breast appearance years after the therapy was judged as good to excellent in 94 percent of the women who had undergone WBI and 95 percent of the women who had APBI.
Ten years after treatment, the study found the following:
- No difference in cancer recurrence in the same breast (4 percent for each) or regional recurrence (1 percent each).
- Distant spread (metastasis) occurred in 3 percent of the women who received WBI and 6 percent of those who had APBI.
- Disease-free survival (period during which there was no evidence of cancer) was 93 percent in the WBI group and 91 percent in the APBI group.
- Cancer developed in the other breast in 9 percent of the women who had WBI and 3 percent of those who had APBI.
- Cancer-specific survival was 94 percent among WBI recipients and 93 percent among APBI recipients.
- 83 percent of the women who had WBI were still alive, compared to 75 percent of women who had APBI.
“These data represent one of the only APBI series with prolonged follow-up and show similar outcomes in a matched group of patients undergoing WBI or APBI,” the authors concluded.
"Ongoing studies of the equivalence of local radiation therapy on breast cancer recurrence and disease-free survival as compared to more traditional radiation therapy is analogous to studies proving the relative equivalence on those same parameters when lumpectomy and radiation were compared with the mastectomy 30 years ago," Rob Fuller, MD, surgical oncologist with Capital Surgeons Group, told dailyRx News.
"Combined with our better understanding of the biology of breast cancer now than in the past, in general we are becoming more aggressive with systemic treatment (chemotherapy) and less aggressive with local therapy (surgery and radiation) for patients with breast cancer," explained Dr. Fuller.
Findings from this study were presented at ASCO Breast Cancer Symposium 2013.
All research is considered preliminary before it is published in a peer-reviewed journal.