Over the last 30 years, the approach for treating breast cancer has changed dramatically, from the maximum tolerated treatment to the minimum effective treatment.
Over the last 30 years, the approach for treating breast cancer has changed dramatically, from the maximum tolerated
treatment to the minimum effective treatment. Radical mastectomy followed by intensive radiation to the chest wall and lymph node areas at risk has given way to breast-conserving treatment (BCT). This change is a result of the widespread use of mammography to detect cancer at an earlier stage, and a number of randomized clinical trials that demonstrated the effectiveness of less intensive treatment for breast cancer.
In BCT, the patient has the tumor surgically removed and waits three or four weeks to recover from the surgery before beginning adjuvant external beam radiation treatments (EBRT) for five weeks. Some BCT patients also receive an additional one to two weeks of external beam electron boost radiation treatment directed to the site of the tumor. Despite improvements in surgical techniques, modern external beam radiation equipment, and improved hormonal and chemotherapy regimes, women who receive conventional BCT still have a local recurrence rate of 1-2% per year.
New Technology Offers New Hope
A new technology that initiates the radiation treatment at the time of surgery is giving breast cancer patients new options—and, more importantly, new hope. Intraoperative Electron Beam Radiation Therapy (IOERT) reduces the overall dose that needs to be delivered with EBRT, and in some cases, may eliminate EBRT alltogether. IOERT can also be used in conjunction with oncoplastic surgery, which combines breast-conserving surgery with plastic reconstruction of the breast for excellent cosmetic results.
IOERT is delivered directly to the tumor bed, where it can effectively eradicate microscopic residual disease, making subsequent adjuvant treatment much more effective. Because it does not have to pass through healthy skin, organs, and tissue, IOERT can be delivered at higher and more effective cancer-killing doses. Guided by the radiation oncologist’s clear view of the site as well as intraoperative ultrasound, IOERT allows the electron beam to be more accurately targeted. IOERT also eliminates the traditional delay between surgery and initiation of external radiation therapy that can give cancer cells a chance to recover and spread.
IOERT Studies Show Promising Results
The effectiveness of IOERT is supported by several European studies. In one study, 190 women received IOERT (as a “bio-boost”) during lumpectomy followed by whole-breast radiation. Their outcomes were compared with those of 188 previously treated women who received lumpectomy alone, followed by whole-breast radiation using an externally applied electron beam boost to the tumor bed. After a median follow-up period of 51 months, no local tumor recurrence occurred in the IOERT group; after a median follow-up period of 81 months, 6.4% of the other group had experienced local breast cancer recurrences.
Dr. Felix Sedlmayer, chairman of radiation oncology at the University of Salzburg, was the principal investigator in this study and also the lead investigator of a “pooled analysis” involving 1,104 women from six different European centers who had received IOERT as a bio-boost during lumpectomy. More than 52% of the women had one or more unfavorable factors: they were younger than 40, had larger tumors, a higher grade of cancer, or positive nodes. After a median follow-up of more than 51 months, there were only five in-breast recurrences, yielding a local tumor control rate of 99.3%, a truly excellent achievement for this diverse patient population.
The apparent local control improvement from the bio-boost at five years is encouraging, because several recent studies have shown that improved local control in early stage breast cancer at five years correlates with a survival benefit at 15 years. Although these bio-boost studies are not yet randomized, the results are nevertheless impressive. IOERT can also be used for post-menopausal women with small tumors and no positive nodes.
A recently completed randomized trial studied whether a single IOERT dose during breast cancer surgery can replace the entire five-to-seven-week post-surgery course of EBRT. Although the results of this study will not be available for about two years, the hospital conducting the study recently reported on 1,105 women outside of the randomized protocol who were treated with this technique. They appear to be doing as well as would be expected had they been treated with conventional BCT.
For most women, a diagnosis of breast cancer is devastating. In addition to their fears and concerns about survival and health, they must also confront emotional and psychological issues associated with personal identity and sexuality. IOERT offers convenience, peace of mind, and new hope for breast cancer patients by fighting cancer at its source, providing better local control, shortening treatment cycles, and producing fewer side effects. Most importantly, IOERT helps save lives.
Donald A. Goer, PhD, is president and CEO of IntraOp Medical Corporation,a leading designer of systems for intraoperative radiotherapy treatment of cancer, coronary/vascular restenosis, and other medical applications.