New Radiation Therapies and Shorter Treatment Times Effective on Breast Cancer

A more powerful, yet shorter treatment with radiation therapy has been found to be equally effective as the long-established extended course of treatment for many breast cancer patients, according to Canadian researchers. After 12 years of monitoring a large group of breast cancer patients, the researchers have reported that three weeks of radiation treatment are just as successful as the normally endured schedule of five to seven weeks of daily treatment for women diagnosed with early-stage breast cancers. The findings are strong evidence that the necessary course of radiation can safely be reduced, making life easier for patients while reducing clinic waiting lists and allowing treatment of more women without the additional costs of purchasing more equipment.
Experts agree that the new findings could change the U.S. standard of care and offer women the welcome chance to complete their treatment faster, allowing them to get on with their normal lives. In the United States alone, approximately 180,000 women are diagnosed with breast cancer annually. Although most need radiation, 30 to 40 percent of these patients may be candidates for the abbreviated treatment that currently is widely available in Canada and parts of Europe and scarcely found in the U.S.
The most ideal candidates for the shorter radiation treatment are women with early breast cancers that have not spread to the lymph nodes and have had the cancer removed by lumpectomy. Although women with such early stage cancers often do not need to undergo chemotherapy, radiation is used to keep cancer from returning in the breast where it occurred by killing any remaining tumor cells that may have escaped surgery. Cancer cells are more vulnerable to radiation than are normal, healthy cells.
With survival rates in the first five years having reached 98 percent of women with early-stage cancers, considering the quality of life of patients is now a real possibility when deciding treatment options. Currently, some women who could have the option of a lumpectomy followed by radiation choose to have a mastectomy in order to avoid radiation, because they cannot travel to a clinic for daily treatments.
The study participants included 1,234 women who began treatment between 1993 and 1996 at one of eight hospitals. Half of the participants underwent the standard regimen of 25 treatments in 35 days consisting of five treatments per week for five weeks, while the other half received 16 treatments in only 22 days. The shorter treatment utilized a higher daily dose of radiation although the total cumulative dose was lower.
During the 12 year study, the outcome concerns remained that a lower overall dose could allow for recurrences and that the higher daily doses could cause damage to breast tissue, the heart or the lungs since radiation injuries can take up to a decade to become evident. However, the findings showed no significant differences between the groups after 10 years. Both recurrence rates were 6 to 7 percent, with approximately 70 percent of both groups experiencing a little discoloration, scarring, or shrinkage from the radiation therapy.
Dr. Timothy Whelan, lead author of the study and director of the supportive cancer care research unit at the Juravinski Cancer Center in Hamilton, Ontario commented regarding the shorter treatment, “Our patients really like it because it’s much more convenient.” He also noted that, “It’s preferred because…in Canada there may be more distance to travel to a radiation facility."
According to Whelan, the new findings reflect a longer-term follow-up than those presented five years ago. Referring to the shorter but more intense radiation treatments he said, "We first presented our results five years ago, but many oncologists were reluctant to adopt this. They were concerned about long-term effects."
Healthcare providers continue to experiment with new ways to treat only affected parts of the breast rather than the breast in its entirety, to make the treatment safer by avoid exposure of the heart and lungs to radiation.
In a second study presented at the recent ASTRO conference, Dr. Peter Beitsch, a surgical oncologist at Medical City Dallas Hospital, Dallas, used a type of accelerated partial breast irradiation (APBI) that utilizes a radiation seed implant known as balloon brachytherapy. Beitsch said that the implants work very well as an alternative to whole breast radiation. Once a tumor is surgically removed a small balloon is inserted into the cavity and a catheter is attached to the balloon, which carries a high radiation dose by means of tiny radioactive seeds.
Beitsch used the Mammosite Radiation Therapy System, which was approved by the FDA in 2002, in the post-approval study funded by the manufacturer. Of the more than 1400 women in the study, Beitsch reported on 400 followed for almost 4 years now. The study found that the rate of early complications, as well as cosmetic results, were similar to those of patients receiving standard therapy. There were about 2 percent of tumor recurrences. When compared to the zero to 5 percent range of recurrences for whole breast radiation, the results are comparable.
According to Beitsch, women age 45 or older with tumors of three centimeters or less and a diagnosis of ductal cancer or ductal cancer in situ (DCIS) are the best candidates for the seed therapy. This accounts for about 40 percent of women diagnosed with breast cancer.In yet a third study presented at the conference, proton therapy, a form of external beam radiation therapy, reportedly reduced the risk for the development of a secondary malignancy in cancer patients by double when compared to traditional radiation therapy that uses photons.
Proton therapy is targeted radiation that distributes less radiation to the areas surrounding the cancer than photon radiation. Nevertheless, with proton therapy, neutrons are produced and scattered, causing some experts to fear that the scatter radiation could increase the chances for secondary cancer.
In the study, 503 patients with different cancers who underwent proton therapy were compared to 1,600 patients who had photon therapy. After a year or more of monitoring, only 6.4 percent of the proton therapy patients developed a second cancer, compared to 12.8 percent of the traditional photon therapy patients. These results suggest that fears about scatter radiation may be unjustified.