Important New Advance in Breast Cancer Treatment: Intraoperative Radiation Therapy
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IMPORTANT NEW ADVANCE IN BREAST CANCER TREATMENT:
INTRAOPERATIVE RADIATION THERAPY
The surgical management of breast cancer has undergone several very important revolutions over the past 20 years. When I began medical school, there was essentially only one treatment available to women newly diagnosed with breast cancer. Irrespective of how small or how large the tumor, every woman was advised to undergo complete removal of her breast (mastectomy). Likewise, a radical removal of the lymph nodes in the armpit area, on the same side as the breast cancer, was also considered mandatory back then, even if there were no clinically enlarged lymph nodes detected prior to surgery.
Thanks to a landmark prospective clinical research study, conducted by the National Surgical Adjuvant Breast and Bowel Project (NSABP) cancer study group, we know that radical mastectomy offers no improvement in breast cancer survival when compared to simply removing the breast tumor with a margin of normal surrounding breast tissue (partial mastectomy, also known as “lumpectomy”). The NSABP B-04 study, which was initiated in 1971, has now reached an average duration of patient follow-up of nearly 30 years, and the compelling findings of this study have made it possible for hundreds of thousands of women with breast cancer to preserve their breasts.
More recently, the application of the sentinel lymph node (SLN) concept has enabled surgeons to locate the one, or a couple, of lymph nodes most likely to contain breast cancer cells. By removing a very small number of SLNs, the complications associated with removal of the armpit (axillary) lymph nodes can be reduced by ten-fold when compared to removal of most of the lymph nodes in the axilla. Since 60 to 65 percent of all breast cancer patients will not have their SLNs involved with breast cancer cells, the vast majority of these women are now able to avoid a complete axillary lymph node dissection, and its associated 30 to 35 percent incidence of complications, including chronic swelling of the arm (lymphedema), numbness or chronic discomfort the arm, and decreased shoulder mobility and strength. (Unfortunately, at the present time, women with “positive” SLNs are still advised to have their remaining armpit lymph nodes surgically removed.)
For most women, “breast-conserving” surgery carries an additional price, though. Radiation treatments are administered to the breast after all other treatment has been completed, as this has been shown to cut the risk of recurrence of cancer within the same breast in half. For most patients, conventional “external beam” radiation therapy lasts approximately 5 weeks. Although these treatments are given on an outpatient basis (Monday through Friday, typically), this somewhat prolonged duration of treatment is enough of an inconvenience to some breast cancer patients that they, ultimately, decide to undergo mastectomy instead of lumpectomy combined with radiation.
A number of techniques have been devised to speed up the process of radiation therapy for breast cancer patients. These approved methods of accelerated breast irradiation include the use of more frequent treatment sessions, using a standard “external beam” radiation machine, as well as various forms of radiation treatments collectively referred to as brachytherapy. Unlike external beam irradiation, where beams of radiation pass from a machine, and through space, before entering the breast from outside the body, brachytherapy techniques all involve placing a device inside the breast (within the lumpectomy cavity). These catheter-based brachytherapy devices are then loaded with radioactive seeds that emit therapeutic radiation to the inside of the breast. Based upon recent research data, brachytherapy appears to be just as effective as conventional external beam irradiation in reducing the risk of breast cancer local recurrence. However, both brachytherapy and other forms of accelerated breast irradiation still require 1 to 2 weeks of treatment.
One potential alternative to standard accelerated breast irradiation methods has been the use of a one-time treatment of the lumpectomy cavity with radiation at the same time that the patient undergoes lumpectomy in the operating room. Intraoperative radiation therapy has been utilized for other types of cancer, primarily within the abdomen, but its usefulness in treating breast cancer has been less clear. Now, a newly published prospective, multi-institutional clinical study, just published in the journal Lancet, offers hope that a single application of radiation, administered while the patient is still under anesthesia at the time of her lumpectomy, might be able to replace the more cumbersome and time-consuming radiation therapy modalities currently in use.
This clinical trial was started in 2000, and enrolled 2232 women with newly diagnosed breast cancer. Half of these women underwent conventional external beam radiation therapy, while the other half of these volunteers underwent a single episode of intraoperative radiation treatment at the time of their breast cancer surgery (it should be noted that 14 percent of the women who were randomized to receive intraoperative radiation therapy also subsequently received external beam irradiation as well).
After an average follow-up duration of 4 years, there was no significant difference in the incidence of local breast cancer recurrence between these two groups of women. Moreover, the incidence of complications associated with radiation therapy was significantly lower in the group of patients who underwent a single intraoperative treatment with radiation when compared to the conventional external beam radiation therapy group.
While the 4-year follow-up of this group of breast cancer patients is too brief to definitively conclude that a single dose of intraoperative radiation provides equivalent long-term protection against local breast cancer recurrence when compared to external beam irradiation and brachytherapy, this study still offers the hope of yet another significant advancement in the treatment of breast cancer. If intraoperative radiation therapy appears to be as effective as conventional breast irradiation after at least 10 years of patient follow-up, then I predict that eligible breast cancer patients will, someday, be routinely treated in this manner. Ultimately, this approach to breast cancer treatment has the potential to significantly increase the efficiency and speed of patient care while simultaneously decreasing the overall cost of such care. It will also improve the quality of the lives of millions of women, over time, and free them to move on with their lives more quickly after receiving the diagnosis of breast cancer.
To learn more about the prevention of breast cancer, and other cancers, look for the publication of my new landmark book, “A Cancer Prevention Guide for the Human Race,” in the summer of this year.
Disclaimer: As always, my advice to readers is to seek the advice of your physician before making any significant changes in medications, diet, or level of physical activity
Dr. Wascher is an oncologic surgeon, a professor of surgery, a cancer researcher, an oncology consultant, and a widely published author
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