Tuesday, February 24, 2004

A Debate on Radiation in Breast Cancerfrom The New York Times.

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.

The benefits of post-mastecomy radiation in patients with 3-4 or more positive nodes began after these articles appeared in the New England Journal of Medicine. This was in spite of the weaknesses of the studies, mainly the low numbers of lymph nodes removed in the Danish study (average of seven) and the low numbers of patients in the Canadian study. So the standard of care has evolved that premenopausal women with four or more positive nodes receive post-mastectomy radiation, mainly to prevent loco-regional recurrence. The benefit on overall survival is less clear.

The debate is about what to do with the patient with 1-3 positive nodes. Patients like this in my practice have received radiation if they had larger primary tumors, extracapsular tumor in a node, or close margins. There can be some benefit to these patients from post-mastectomy radiation:

Radiation therapy after mastectomy reduces loco-regional recurrence rates for breast cancer patients with positive lymph nodes, positive surgical margins, or both, according to the results of a large retrospective study presented at the 44th Annual Meeting of the American Society for Therapeutic Radiology and Oncology ....For all patients treated with postmastectomy radiation, the total locoregional recurrence rate (with or without distant metastases) was 10%, compared with 19% for the patients who did not receive postmas-tectomy radiation, Dr. Woodward reported.
Looking specifically at the subset of 502 patients with T1-T2 stage tumors with one to three positive nodes, the investigators found that freedom from locoregional recurrence in patients treated with radiation was 97% vs 87% for patients not treated with radiation.
(Oncology News International Vol 11, No 12 (December 2002))

Again, keep in mind that the above is from a retrospective trial. The Southwest Oncology Group's randomized Intergroup trial (mentioned above) was closed due to lack of enrollment. Back to the Times...

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.

The question remains is the risk of increased lymphedema, post-radiation skin changes, and difficulties with breast reconstruction worth it for women with only 1-3 nodes? As with most issues related to breast surgery, it is largely up to the patient:

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.

Just remember the difference in recurrence-free survival and overall survival as the line is blurred by this paragraph:

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.

As I posted earlier, that link has not been solidified yet.

ADDENDUM: Personally I think that the reduction of loco-regional recurrence is reason enough to offer radiation to these patients as local recurrence after a mastectomy can be difficult to treat, requiring myocutaneous flaps in some cases.
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