Breast Cancer Radiation Therapy - Kenneth Tokita, MD
Dr Tokita is the founder and Medical Director of the Cancer Center of Irvine. He is a world-renowned radiation oncologist and a key member of the Breastlink multidisciplinary team.
Historical Development of Breast Cancer Treatment
There has been a gradual improvement in the treatment of localized breast cancer. Initially incurable, breast cancer therapy has not only improved cure rates but also allowed women to keep their breasts.
At the turn of the century, there was no known cure for breast cancer. Dr Halstead first showed it could be cured with a dramatic new operation, called the Halstead Radical Mastectomy. This surgery involved removing the entire breast, pectoral muscle and lymph nodes. As horrible as this sounds today, it was a dramatic step in showing that breast cancer was potentially curable.
The first real modification occurred in the late 1950s. The pectoral muscle was left, and resulted in the Modified Radical Mastectomy. The cure rates were later proven to be identical to the Halstead Radical, but with dramatic improvement in cosmetics and decrease in complications, primarily decreased lymphedema (arm swelling) and improved arm mobility. The cosmetic improvement was the ability to wear lower-cut blouses and short sleeves. These seem modest today but were huge improvements then.
Plastic Surgical Reconstruction The early 1960s saw the introduction of plastic surgical breast reconstruction. Cosmetics became a very important factor as physicians became increasingly aware of the psychological impact mastectomy was having on breast cancer survivors.
Lumpectomy (Breast Preserving Therapy) The mid 1960s saw an innovative surgeon, Dr Oliver Cope, and his cohort radiation oncologist Dr Sam Hellman invent a dramatic new procedure. Accepting for the first time that radiation could indeed cure small amounts of cancer, they combined "limited" surgery with breast radiation to preserve the breast. This procedure is affectionately now called "lumpectomy" (other references are "quadrant resection", "wedge resection", "wide local excision" etc), and this surgery is followed by radiation. Again the long-term studies showed equivalent cure rates but dramatically better acceptance of treatment by women and spectacular improvement in post-cancer treatment psychological healing.
Since the widespread acceptance of lumpectomy as primary therapy for breast cancer, there have been a number of innovations to the overall technique. Initially, the lumpectomy was followed by five weeks of external beam radiation (EBRT) combined with interstitial brachytherapy (boost radiation).
External Beam Radiation Therapy (EBRT) The EBRT was and still is accomplished with a radiation machine called a linear accelerator (high-energy x-ray machine). Treatments are given daily as an outpatient, Monday through Friday, and take 10 to 15 minutes on the machine.
Brachytherapy Boost Radiation The original brachytherapy boost was accomplished by surgically inserting a number of needles through the breast in the area where the original tumor had been removed and where there may be residual cancer cells. The tubes were then "loaded" with a radioactive material called Iridium-192 (Ir-192). Iridium was delivered to us as tiny rice-sized pellets imbedded in plastic tubes. This "ribbon" of Ir-192 was slid into the hollow needles and left in long enough (typically two days or 48 hours in the hospital) to deliver the radiation dose needed to destroy the residual or remaining cancer. This comprised the "boost" radiation and allowed the delivery of very high doses of radiation to the potentially largest clumps of cancer cells that may have been left behind at surgery.
Team Approach to Cancer Treatment Indeed, it was Dr Cope's confidence in his radiation therapy colleagues that allows this treatment to be given, rather than removing the whole breast. This may have been one of the first examples of improved cancer care coming out of the Team Approach.
Dr Tokita had the privilege of learning directly from Dr Cope in 1976 and introduced Breast Preserving Lumpectomy and Radiation to Southern California, while founding and directing a Radiation Department in Torrance California.
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Subsequent Therapeutic Changes
Many subsequent variations have occurred. The first variation was to drop the brachytherapy and accomplish "the boost" with the linear accelerator, using smaller radiation fields or another form of radiation available on the newer accelerators. This different radiation is the "Electron boost". This is the most commonly used "boost" radiation done today.
The entire radiation process typically takes seven to eight weeks, five weeks of external beam and three weeks of electron boost radiation. This delivers upwards of 35 to 40 treatments. That's a lot of visits to the radiation department.
In an attempt to shorten this long course of radiation, some surgeons and radiation therapists have begun to apply the previous "needle" brachytherapy to the breast as the only radiation. This is called "interstitial needle brachytherapy" and this therapy does not use any EBRT. It is completed in five days rather than eight weeks.
This can be done safely in:
- Small tumors (ideally, less than 2 cm)
- Non-aggressive tumors (well differentiated, or slower growing and less likely to spread early)
- No metastasis (no cancer spread)
- Wide surgical lumpectomy margins, lymph nodes not involved with cancer, and adequate spacing from the skin.
- Exclusions, tumors called lobular, and diffuse ductal carcinomas in situ (DCIS) are considered inappropriate for this therapy.
Mammosite® is a new brachytherapy device Recently this new brachytherapy approach has been approved by the Federal Food and Drug Administration and now accepted by all major insurance programs and Medicare. This new procedure is accomplished by having a plastic catheter with a saline or water-filled bulb inserted into the cavity created by the surgeon. The catheter is then "loaded" with Iridium-192 to radiate the cavity and the immediate surrounding tissue. The trade name for the catheter is Mammosite. This treatment is similar to the interstitial needle brachytherapy, and is completed in five days.
Intraoperative Radiation Therapy (IORT) This is an older technique previously used in the abdomen for pancreas and stomach cancer. Recently, it has been applied to breast cancer during the excision of small confined breast tumors. Since it is performed during the surgery, it is referred to as intra-operative radiation therapy. This shortens the radiation even more, from eight weeks to five days, to one treatment on the day of surgery.
How practical or curative this procedure can be will require study, volunteers, and centers able to accomplish this complex procedure.
Which treatment is right? We would advise patients not to make decisions on a specific treatment before they have a good understanding of the entire problem and the implications of each treatment alternative. The team review may lead to a different recommendation. Ultimately, the final decision on which is best for each patient will be determined by the treatment team and the patient. Often this recommendation will offer choices, but occasionally not.
All Cancer Treatments are Potentially Dangerous All cancer treatments are destructive to cancer cells, and therefore run the risk of causing complications, sometimes severe.
We are therefore always exploring ways to modify and improve our treatments, and eliminate treatments where we can.
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Who are These Treatments For?
These treatments need to be individualized. In fact the newer, shorter treatment courses may be for only a limited number of breast cancer patients. Some estimate these treatments will be acceptable for as few as one out of three. Only time will tell.
It is also important to realize that these newer treatments treat only a portion of the breast surrounding the site of tumor removal. The standard radiation treats the whole breast. There is no way that interstitial needle brachytherapy, mammosite and IORT will control the whole breast as well as whole-breast radiation. However, with careful screening and patient selection, we feel that the overall cure rates should be comparable and acceptable.
The tremendous advantage is the very short overall course of radiation: one day or one week versus seven weeks.
The Cancer Center of Irvine has over 30 years of experience with standard external beam radiation therapy (EBRT). During this time of working alongside Breastlink patients we have achieved a 93% cure rate of breast cancer (no evidence of disease at 12-15 years).
Only time and many patients treated will tell if these other newer techniques are as effective in curing patients as standard EBRT. Each patient who undergoes treatment with newer procedures must understand this and be willing to accept a potential difference in cure rate.
Obviously, we believe these treatments will be very close to EBRT, or we would not morally be able to offer or promote them as an alternative.
Breast cancer treatment has become increasingly sophisticated over the last 20 years. There are now many more types of radiaiton treatment to be considered. Any women involved in making decisions about her breast cancer treatment needs to be aware of the different options and which one might best benefit her unique situation.
For more information on radiation therapy offered at the Cancer Center of Irvine, click here.
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