July 11, 2003
Trial to test safety of radiating breast from the inside after
lumpectomy
P. Devlin, MD
Many doctors and patients are intrigued by a new procedure that delivers radiation from inside the breast following breast-conserving surgery for early-stage cancer. This innovation dramatically reduces the treatment period from several weeks to a matter of days, and it's hoped that it will prove as effective as standard external-beam radiation in preventing recurrence of cancer.
But to make certain the method is safe, Women's Cancers Program researchers have launched a small clinical trial to look for side effects of the treatment, such as infection, abscesses, and skin damage. If the method seems feasible, they say, they will then undertake larger tests of its effectiveness.
A team led by radiation oncologist Phillip Devlin, MD, of Dana-Farber and Brigham and Women's Hospital, is recruiting 15 carefully selected patients with early breast cancer to undergo the new treatment, known technically as High Dose-Rate Intracavitary Brachytherapy.
"We are very enthusiastic about moving forward, but the safe way to proceed is a pilot study followed by Phase I and Phase II trials," says Dr. Devlin. He adds that physicians in some parts of the country are already offering the treatment to women without enrolling them in studies of its safety and effectiveness.
With breast-conserving surgery (lumpectomy or partial mastectomy) even cancer caught and removed early is likely to recur without additional treatment to eradicate remaining cancer cells. Long-term studies have shown that the risk is very low if external radiation is given following surgery.
The drawbacks are that the entire breast receives radiation - not just the area adjacent to the tumor - and that treatments take 5 to 6 weeks to complete, posing problems for women who work or live far from a medical center. In fact, says Dr. Devlin, studies show that only 40 percent of women in the United States who are eligible for breast-conservation treatment choose it, in part because of the logistical barriers to radiation treatment.
Another form of inside-the-breast radiation is interstitial brachytherapy. A radioactive source is inserted sequentially through 12 catheters, with treatments stretching over several days. The procedure requires a skilled and experienced team and the use of an operating room for the initial catheter implants.
In contrast, the intracavitary method is simpler to perform than interstitial brachytherapy. The device consists of a catheter with an inflatable balloon at its tip. Using local anesthesia, physicians make a small incision in the skin and insert the catheter into the hollow area created by the tumor's removal. The balloon is inflated inside the cavity, with the breast tissue molding to the balloon in a spherical form so that the tissue will be evenly treated. Next, the doctors insert a source of high-dose radiation through the catheter and into the center of the balloon. After treatment, the radiation source is removed. Two treatments a day for five to eight days are the standard course of therapy. Finally, the catheter is removed. In initial tests, the procedure left only a single, small scar.
The researchers are using stringent criteria to select volunteers with a very favorable outlook and minimal risk of complications. Patients must be postmenopausal with small, unaggressive tumors of a certain type (ductal) with no cancerous lymph nodes. The subjects will remain in the study for 60 days.
For information about the trial, contact Julia Kazakin, MD, in Dr. Devlin's office at (617) 632-2743.
