New Cancer Therapy Easier on the Patient
By Judy Foreman
04/20/2004

Eighty-two year old Marie Desilets lives in Dunstable, about an hour's drive from Brigham and Women's Hospital in Boston. When she discovered that she needed radiation for breast cancer a year or so ago, she faced a dilemma.

She could get regular radiation treatments, which would involve being in Boston 5 days a week for seven weeks. Or, she could opt for a new type of radiation that involves only 10 treatments -- given twice a day for 5 days. In the standard method, the whole breast is irradiated; in the new one, radiation is aimed only at the exact spot where the tumor was.

Desilets chose the latter, and went shopping every day between the first and second treatments. "It was a piece of cake," she said. "I highly recommend it. I felt great the whole time."

More than half of women with relatively small tumors opt to skip a lumpectomy and instead have their entire breasts removed -- usually to avoid radiation. Radiation, which requires regular treatments for weeks and has side effects including skin irritation, is a huge hassle for those who live a long way from a medical center or whose work schedules make it difficult to spend part of every day getting treatment.

But the new procedure that Desilets had, called "accelerated partial breast radiation," is likely to change such thinking.

An estimated 71,000 women each year may be potential candidates for the procedure which is already available at many medical centers, thanks to growing patient demand. Many insurers already pay for it. It's too soon to say that whether the new technique is ready to replace the old, which is supported by decades of practice and studies.

"The quandary is that the rationale for partial breast irradiation is compelling, but we are moving away from something that is tried and true with excellent long-term results to something that has at least something of a question mark," said Dr. Jay Harris, chief of the department of radiation oncology at Brigham and Women's Hospital and the Dana-Farber Cancer Institute.

For that reason, he and others suggest that women considering partial breast irradiation be treated through clinical trials, a number of which are underway or about to start.

On the other hand, the risk of the new approach is probably small. Almost all the time, when a cancer grows back in the breast where it started, it does so right in the area where the initial tumor was, not in a more distant part of the breast, said Dr. Phillip Devlin, director of brachytherapy at Brigham and Women's Hospital and the Dana-Farber Cancer Institute. That suggests tightly-targeted radiation should do the trick.

Indeed, while radiation is important for reducing the risk of recurrence of cancer in the same breast, it does not affect overall survival. Unlike chemotherapy, whose goal is to knock out cancer cells anywhere in the body, "radiation controls local recurrence," said Dr. Oscar Streeter, associate professor of clinical radiation oncology at the Keck School of Medicine at the University of Southern California. It" does not have an effect on overall survival."

Because of its newness, partial breast irradiation is generally recommended only for women with small tumors in only one section of the breast and no signs of cancer spread to the lymph nodes.

In one of three forms of the new procedure, called catheter-based or interstitial radiation, doctors numb the breast, then insert 10 to 20 small tubes into the area where the tumor was. They then insert a radioactive "seed" containing Iridium 192 into each catheter, leave it in briefly, then take it out and put it in the next catheter.

The whole procedure takes about 10 minutes, said Dr. Frank Vicini, chief of oncology at the William Beaumont Hospital in Royal Oak, MI and principle investigator of a new trial of partial breast irradiation in 3,000 women. The radiation is given twice a day for five days -- the tubes stay in the whole time -- and provide the same tumor-killing effect as standard radiation, said Vicini, author of a study in 2003 of nearly 400 women, half of whom got the new radiation and the other half, whole-breast radiation. After 5 years, the study showed, there was no significant difference in the rate of local recurrence.

A second approach is with a device called the MammoSite, which involves placing just one catheter into the cavity where the tumor was. So far, women receiving MammoSite treatment have only been followed for about two years, but the data look promising.

The third, and newest, approach involves an old-style external beam and is called 3D-conformal radiation or a similar technique called, IMRT, for intensity-modulated radiation therapy. Instead of targeting the radiation to the whole breast, the beam is aimed with exquisite precision, using CT scans, to just the area where the tumor was.

For Marie Desilets, who had the Mammosite procedure,  the new radiation was a breeze. "I didn't feel anything. My skin didn't get red. There were no repercussions at all." 

Judy Foreman is a Lecturer on Medicine at Harvard Medical School. Her column appears every other week. Past columns are available on www.myhealthsense.com.

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