Posted on 02/24/2004 4:33:25 PM PST by neverdem
Radiation treatment is being prescribed for more and more breast cancer patients, including women who would have been told just a few years ago that they could skip it.
The added therapy mostly affects those women who are treated with mastectomy and chemotherapy, and have fairly good prognoses at what is called Stage 2 cancer.
But cancer experts and doctors are divided over whether these women really need radiation to improve their chances of survival.
For some, radiation may enhance their prospects of preventing a recurrence of their breast cancer. But whether that translates into increases in the chances for long-term survival is not clear.
Some doctors are simply prescribing radiation; others want to wait for more data.
Harvard's affiliated hospitals take different approaches, said Dr. Abram Recht, deputy chief of radiation oncology at Beth Israel Deaconess Medical Center. "At Mass General, they tend to be quite aggressive and will radiate these women," he said. "At Brigham and Women's they tend not to. We're somewhere in the middle."
The debate does not concern breast cancer patients who have lumpectomies or patients who receive mastectomies and have more than three malignant lymph nodes. In those cases, experts generally agree that radiation after surgery increases the chances of survival.
Rather, at issue are mastectomy patients who have one to three positive axillary, or underarm, lymph nodes. Some 15,000 to 20,000 women annually fall into this gray zone.
"Recommending or not recommending radiation therapy has extremely significant consequences for women," said Dr. Patrick I. Borgen, chief of breast service, department of surgery, at Memorial Sloan-Kettering Cancer Center in New York.
High-dose radiation is delivered to precise spots on the body through what looks like a large X-ray machine. It is an arduous treatment, delivered for a few minutes five days a week for six to eight weeks. While the sessions are painless, they cause fatigue and may produce sunburnlike sensations.
Combined with removal of lymph nodes, radiation doubles the rate of lymphedema or permanent swelling of the arm. Radiation may increase the long-term risk of dying from cardiovascular or lung diseases, though advances in radiation therapy have greatly reduced these risks.
In addition, radiation limits the choices women have for reconstructive surgery, eliminating the option for some. Others must delay reconstruction for six to nine months.
Women are treated with radiation to destroy tumor cells left in chest walls and lymph nodes. Those cells can, with time, spread to other parts of the body.
The use of postsurgical radiation began to surge after the results of two large medical trials appeared in The New England Journal of Medicine in 1997. One study from Denmark involved 1,708 premenopausal women who received surgery and chemotherapy, with or without radiation, for their Stage 2 and 3 cancers. Those who received radiation reduced by two-thirds their risk of a cancer recurring locally over 10 years.
More important, they had a 10 percent improvement in survival. The 10-year survival increased to 54 percent from 45 percent. A smaller trial from Canada with 318 women found similar results.
In 1999, the American Society for Therapeutic Radiology and Oncology published a consensus statement, and in 2001, the American Society of Clinical Oncology published guidelines. Each recommended postmastectomy radiation to women with four or more positive lymph nodes.
"Almost overnight, following these consensus conferences, the majority of the country switched to radiating women with four or more positive nodes," Dr. Borgen said. That led to a drastic increase in postmastectomy radiation. Previously, only women with 10 or more positive nodes, a very advanced cancer, were routinely given radiation, he said.
The guidelines did not affect women who were found to have one to three positive lymph nodes. Experts in the United States believed that radiation treatment might not be as effective here.
The studies done elsewhere showed higher recurrence rates for women in that category who did not receive radiation than for American women in similar circumstances.
Some experts say the differences emerged because of less aggressive surgical techniques in Europe. In the Danish study, surgeons removed an average of 7 lymph nodes; in the United States, they removed an average of 15 to 17 nodes.
Because American women have had a lower local recurrence rate, the value of radiation therapy is less clear, Dr. Borgen explained.
"What's clear is that women with a 25 to 30 percent risk of local recurrence can improve their chance of being cured by 10 percent," said Dr. Thomas A. Buchholz, program director of breast radiation oncology at the University of Texas M. D. Anderson Cancer Center in Houston. "The controversy is, Who has that risk?" Not, he said, the women with the fewest number of positive lymph nodes.
There is no question that if given radiation, these women would further reduce the rate of recurrence by two-thirds, bringing it down to 3 to 5 percent.
But whether that translates into a survival benefit — and how much of one — is not known. "At some point there's a law of diminishing returns," said Dr. Recht of Beth Israel Deaconess.
On the other hand, some people say that even a 1 percent improvement in survival is enough to justify therapy.
"We really don't have substantial data to inform our patients about what the risks and benefits are in the one- to three-node positive group," Dr. Borgen said. At Sloan-Kettering, women in this group do not routinely receive radiation.
The argument for treating women is that it is quite possible that by reducing local recurrence of a cancer to 5 percent from 15 percent the survival rate may be improved.
At Duke University, doctors use radiation on anyone who has a single positive lymph node, said Dr. Lawrence B. Marks, professor of radiation oncology there.
"There have been several randomized studies and a survival advantage is seen in every subgroup," Dr. Marks said. "People can poke holes in the studies, but there are a handful of studies with trends in the same direction." None of the studies he mentioned were conducted in this country, though.
To try to answer the question here, experts began a huge randomized study in 1999 that was open to several hundred hospitals. But it ended because researchers were unable to recruit enough women.
Without a study in the United States, breast cancer experts have reassessed the 1997 studies and drawn their own conclusions. More and more are now referring their patients to radiation oncologists for treatment, experts said.
Improvements in technology have also greatly reduced the risks. "All of us feel we are delivering it in a much safer way than we did 10 years ago," said Dr. Beryl McCormick, attending and clinical director of the department of radiation oncology at Sloan-Kettering.
Still, some doctors remain undecided. Certain factors increase the risk of recurrence, nudging a woman with one to three positive nodes into the higher risk category. These factors include having a large primary tumor of 2 inches (5 centimeters) or greater, having cancer that has broken out of the lymph nodes to involve surrounding tissue, and having surgical margins that show some malignant cells.
Some doctors leave it to the patients, who, experts agree, know what risks they want to take.
"Patients have an inner sense of what they want to do," said Dr. Lori J. Pierce, an associate professor of radiation oncology at the University of Michigan, who was the lead researcher for the study that failed to draw enough participants. "Patients need to have an informed discussion with the doctors to look at the pros and cons to help them make that decision." That wasn't happening three or four years ago.
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