Shorter Radiation for Cancer of the Breast
Three weeks of radiation treatment work just as well as the usual course of five weeks or more for women with early-stage breast cancers, Canadian researchers have reported, after monitoring a large group of patients for 12 years.
The results, presented Monday at a conference in Boston, provide some of the strongest evidence yet that radiation schedules can safely be shortened to make life easier for patients and to let clinics reduce their waiting lists and treat more women without buying more machines.
Experts say the new findings, from a respected study, could change the standard of care in the United States. The typical schedule now involves five to seven weeks of daily treatments, and most women would welcome a chance to get it over with faster — especially those who work, have small children or live far from the clinic.
About 180,000 women a year develop breast cancer in the United States, and most need radiation. From 30 percent to 40 percent may be candidates for the type of treatment given in the study.
Some centers in this country already offer shorter courses of treatment, but they are more widely available in Canada and parts of Europe.
“We’ve really got to give it serious consideration in the United States,” said Dr. Anthony L. Zietman, a radiation oncologist at Harvard Medical School and the Massachusetts General Hospital Cancer Center, and president-elect of the American Society for Therapeutic Radiology and Oncology. He was not involved in the Canadian study.
But Dr. Zietman cautioned that the results applied only to women with early cancers like those in the study, which were removed by lumpectomy and had not spread to the lymph nodes. Often, women with such early cancers do not need chemotherapy.
Other major changes in radiation are also in the works. Doctors are experimenting with ways to treat just part of the breast rather than all of it, and to make the treatment safer, they are trying to avoid exposing the heart and lungs to radiation.
The purpose of radiation is to keep cancer from coming back in the same breast where it first occurred, by killing any tumor cells that may have evaded surgery and chemotherapy. Cancer cells are more vulnerable to radiation than are normal ones, and the treatment has always been a balancing act between giving enough radiation to destroy the tumor cells but not enough to cause serious damage to healthy tissue and organs.
The changes now being made result in part from the overall success in treating early breast cancers, Dr. Zietman said. Survival rates have climbed so high — 98 percent of women with early-stage cancers survive at least five years — that it is now considered reasonable to step back, look at women’s quality of life and try modifying the regimens to make treatment less onerous.
“It’s a bit of a change in our thinking,” Dr. Zietman said.
Researchers also hope that faster treatment will help make radiation available to more women. Currently, about 20 to 30 percent of women in North American who need it skip it. And some women who could have lumpectomy plus radiation choose mastectomy instead, simply to avoid radiation, because they live too far from a clinic to travel back and forth for all the treatments.
Not all medical centers offer the newer techniques, and they are not right for every woman. But for many women, there are choices now where none existed before — though it may take some effort to find out about them.
“Patients have to speak up,” Dr. Zietman said.
If the standard regimen is recommended, he said, a woman should ask: “Does it have to be that way? Am I one of the people who could be treated with partial breast irradiation, or, if I need the whole breast treated, could it be done in some more abbreviated fashion?”
He added, “Maybe they can, maybe they can’t.”
Some radiation oncologists may resist change, fearful of giving up the tried and true formulas they were taught, Dr. Zietman said. He noted that the standard treatment had 30 years of evidence to back it up, whereas the newer approach had less than half that. But still, the field is moving ahead.
“You don’t give all women with breast cancer the same treatment,” he said. “You base it on what they have, and who they are.”
Canadian researchers decided to study the shorter courses because doctors there and in England had begun using them without a formal trial, to make the most of a limited number of radiation machines.
The study included 1,234 women who started treatment at one of eight hospitals from 1993 to 1996. Half of the women received the standard regimen of 25 treatments in 35 days (five treatments a week for five weeks). The other half had 16 treatments in 22 days. The shorter course used slightly higher daily doses of radiation, but the total cumulative dose was slightly lower.
There were concerns that the lower overall dose would allow recurrences, or that over time the higher daily doses might damage the breast tissue, heart or lungs. Radiation injuries can take years or even a decade or more to show up.
But after 10 years, there were no significant differences between the groups. Both had recurrence rates of 6 to 7 percent, and about 70 percent in both groups had a “good or excellent cosmetic outcome,” meaning the breast did not have much discoloration, shrinkage or scarring from the radiation.
“Our patients really like it because it’s much more convenient,” said Dr. Timothy Whelan, the first author of the study and director of the supportive cancer care research unit at the Juravinski Cancer Center in Hamilton, Ontario. “It’s preferred because, I think to be fair, in Canada there may be more distance to travel to a radiation facility. Patients really are strong supporters of this approach.”
Fran Dowhaniuk, 71, who lives in Hamilton, received the three-week treatment as part of the study in 1995. She liked the idea of finishing more quickly, especially because her daughter’s wedding was coming up.
“I’m really glad I did it,” she said. “I would recommend it to anybody.”
Dr. Whelan estimated that 60 to 70 percent of women with early-stage breast cancers in Canada were already receiving this type of therapy.
Similar results from studies in England that had fewer years of follow-up were published in medical journals earlier this year.
Dr. Catherine Park, an associate professor of radiation oncology at the University of California, San Francisco, said Dr. Whelan’s approach looked extremely promising.
“You can’t argue with the results,” she said.
She said she had treated 20 or 30 patients with this method and hoped Dr. Whelan’s findings would satisfy more-conservative doctors who wanted additional data, so that they would offer it to appropriate patients. She said that the shorter courses would probably also be appropriate for women with a condition called D.C.I.S., ductal carcinoma in situ, a form of breast cancer even earlier than the stage included in the study. But the technique has not been studied in D.C.I.S.
She had one cautionary note: radiation oncologists give some patients a “boost,” meaning five to eight extra treatments aimed just at the tumor bed. Dr. Whelan’s study did not include a boost, and some doctors think that on top of the higher daily doses, it would deliver too much radiation. So some doctors may be unwilling to offer the shorter treatment to patients who they think could benefit from a boost.
Dr. Silvia Formenti, chairwoman of radiation oncology at New York University and the leader of breast cancer research at its cancer institute, called Dr. Whelan’s study impeccable and extremely solid. She said she had treated more than 1,000 patients using a faster schedule of treatments, often including a boost. The median time since treatment is more than five years, and some patients have had slightly more advanced disease than those in Dr. Whelan’s study. So far, she said, the results have been at least as good as those with conventional treatment.
Dr. Formenti uses a technique that she and some other researchers think is important to make the treatment safer: most of her patients are treated lying on their stomach instead of the usual way, on their back. The women lie on a mattress with openings for the breasts; the idea is to let the breasts drop away from the chest, to minimize the amount of the heart and lungs exposed to radiation.
Radiation oncologists are eager to avoid hitting those organs because there is some evidence that irradiating the heart — most likely to occur when the left breast is treated — may increase the risk of coronary artery disease. And even though lung problems linked to breast radiation are extremely rare, there is a potential for scarring and irritation and even an increased risk of lung cancer, particularly in smokers.
“Why not do what is best for women?” Dr. Formenti said, adding that the prone technique is easy for doctors to learn.
She uses CT scans to determine which position is actually safest for each patient.
At Memorial Sloan-Kettering Cancer Center in New York, most women are also treated lying on their stomach, and about half choose the shorter course of treatment, said Dr. Beryl McCormick, the clinical director of radiation oncology.
“I see no difference in how the patients are doing,” she said.
The faster treatment should become standard practice for women with early cancers, she continued, but added, “I’m always surprised to see how long it takes for physicians to change their practice patterns.”
Medical centers are also experimenting with techniques that could shorten the treatment to a few days or even just one day for some women. Those techniques involve treating only about a quarter of the breast, the part nearest the tumor, and the radiation can be given with a machine or with radioactive seeds that are temporarily implanted into the cavity left by lumpectomy. In some cases the entire dose of radiation is given before the patient leaves the operating room.
The partial breast treatments are still being studied, and although the results look promising, more time for follow-up is needed to be sure, Dr. Zietman said.
“I doubt we’ll strongly advocate it until more information is in,” he said.
Dr. Park, who is studying partial breast irradiation, said: “We’re learning who we can treat appropriately with these more limited treatments. We may not know exactly right now, but people should watch. In the next 10 years, we’ll really change the number of things we can offer for breast cancer.”