Prior to 1896, no one had ever had an X-ray picture taken of a body part. This now-ubiquitous diagnostic tool that lets us see deep inside the body simply hadn’t been invented yet. But just 121 years ago, German physics professor Wilhelm Conrad Röntgen described the use of radiation to create X-ray images for the first time. The method soon became a great way to diagnose injury and disease, and the American Cancer Society reports that within three years, radiation was being used to treat cancer.
Although too much radiation was subsequently found to cause cancer, at the right dose its curative properties have been well established. It’s now a common component of treatment for breast cancer, and it can be delivered in a few different ways to either the whole breast or just part of it as external beam radiation or internal radiation.
[See: A Tour of Mammographic Screenings During Your Life.]
Whole Breast or Partial Breast Radiation?
Michael J. Greenberg, a radiation oncologist with Geisinger Health System in Danville, Pennsylvania, says, “the first thing we ask is ‘do you have to treat the whole breast, or can we just treat a portion of the breast?’ For years, we treated the whole breast,” he says, focusing more radiation on the site where the tumor was, but exposing the whole breast to small doses of radiation five days a week for five to six weeks. Even with these treatments, over time, a pattern emerged. “If the cancer came back, it came back about 90 percent of the time in the area where it was to begin with. So the question came up, did we need to treat the whole breast?,” Greenberg says.
Alongside this, radiologists in Europe and Canada were experimenting with condensing treatment using what Greenberg calls “accelerated fractionation of the dose per day,” so instead of a five- to six-week period, the patient would get the same dose of radiation in three or four weeks. This approach seemed to have the same therapeutic results, but with fewer side effects. “The Europeans and Canadians demonstrated with long-term follow-up that the cosmetics were as good or even better with accelerated treatments and the amount of morbidity and fatigue on the patient was better with the shorter course. The control rates and the cure were absolutely the same,” he says.
Today, patients with breast cancers that meet certain criteria — those with less aggressive, early stage breast cancers — may be candidates for partial breast radiation rather than whole breast radiation, and they may be able to receive these treatments over a shorter period of time than previously thought necessary. Those treatments can be delivered externally or internally.
External Beam
The ACS reports that external beam radiation is the most common way of delivering radiation for breast cancer. It can be used in patients who’ve had a mastectomy and those who’ve had a lumpectomy. In either case, the beam comes from a machine outside the body and focuses on where the tumor was located to kill off any cancerous cells that may have been left behind by surgery.
Greenberg says the radiation “machine moves around the patient and it targets the specific areas around the tumor bed. We use a technique called image-guided radiation” to deliver radiation to precisely the right place “within sub-millimeter accuracy, so we can stay away from things like the heart, lungs, opposite breast and other normal structures.” Radiation treatments can damage healthy cells, which can cause heart disease and other side effects, so the more precisely the dose can be delivered, the less likely those complications will arise.
Greenberg says the external radiation beam is on for an average of about five minutes with most patients, and from set up to completion, the whole process takes about 15 minutes. Some patients may be able to have these treatments twice per day with a 6-hour break in between, so there are different ways to deliver the dose needed that can work for patients in different situations. For example, if the patient lives very far away from the treatment center, it may not be feasible to return every day for several weeks, therefore a condensed timeline may be more convenient, and Greenberg says it’s been shown to be just as effective.
[See: 7 Innovations in Cancer Therapy.]
Internal Beam
Internal beam radiation, also called brachytherapy, involves implantation of a device into the body to deliver highly targeted radiation to the tumor itself or the tumor bed if it has been removed. Although it’s considered an advanced cancer treatment, brachytherapy is not exactly a new procedure, says Dr. Sean Park, a radiation oncology researcher at the Mayo Clinic in Rochester, Minnesota. “Brachytherapy is tried and true and the earliest way of delivering radiotherapy, even before the external beam came on.”
But a new approach Park helped develop can, for some early-stage breast cancer patients with no lymph node involvement, reduce the time needed to deliver an appropriate amount of radiation by reducing the waiting period between having the lumpectomy and having the brachytherapy device implanted.
In the past, the tumor would be removed during a lumpectomy and sentinel node biopsy (a procedure that removes one to three of the lymph nodes closest to the tumor to check whether cancer has spread), and then the tissue would be sent to a lab for testing to determine whether the patient was a good candidate for brachytherapy. It could take several days to get the pathology report back, and that would delay the surgery to implant the brachytherapy device in patients eligible for this treatment by up to four weeks, Park says.
With this new approach, the pathology report is completed immediately, while the patient is still under general anesthesia for the lumpectomy. “There’s literally a runner who takes the specimen down the hall to the Frozen Section Pathology Lab where they quickly make sections and look on the microscope to make sure that there’s no tumor touching the boundary of the specimen and the lymph nodes are not involved with the cancer,” Park says. If the lab findings confirm what the surgeon expected of the tumor and brachytherapy is determined to be a good option, the device is implanted right then.
The next day, the patient begins the radiotherapy treatments, which involve a radioactive seed inserted into the device and moved around precisely to deliver radiation exactly where it’s required, thereby reducing the amount of radiation delivered to healthy tissue. (The Mayo Clinic produced a video that shows exactly how it works.)
[See: Breast Pain? Stop Worrying About Cancer.]
Park says that “surprisingly, most patients tolerate [the implanted device] very well,” and few need a painkiller stronger than Tylenol, likely because “the lumpectomy procedure cuts the nerves in the area, so the lumpectomy cavity is numbed up.” Currently, the standard treatment protocol is two radiation treatments per day over the course of five days, for a total of 10 treatments. The device is removed upon completion of radiation treatments.
Park says his team recently completed a clinical trial of the device. Although results aren’t available just yet, early analysis seems to indicate that for certain patients, as few as three treatments with the device may be all that’s needed, meaning these patients could be done with treatment for breast cancer in less than a week.
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What Are the Types of Radiation Treatment for Breast Cancer? originally appeared on usnews.com
