Study examines limited-field radiation for early breast cancer

Main Category: Cancer / Oncology
Article Date: 19 Aug 2003 - 0:00 PDT

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Journal of the National Cancer Institute

Data from a five-year study suggests that limited-field radiation therapy (radiation directed at the tumor site) may be as effective as whole-breast radiation therapy in preventing breast cancer recurrence in women treated with breast-conserving surgery. The study appears in the August 20 issue of the Journal of the National Cancer Institute.

Whole-breast radiation therapy is part of standard treatment for women with early-stage breast cancer who have undergone breast-conserving surgery. However, it has never been clear how much tissue surrounding the tumor bed needs to be irradiated, and whole-breast radiation therapy has been associated with both acute and chronic toxicity. Researchers are now looking at whether limited-field radiation therapy could be a better option for patients at low risk for recurrence.

Frank A. Vicini, M.D., of the William Beaumont Hospital in Royal Oak, Mich., and his colleagues compared rates of local recurrence between 199 women treated with limited-field radiation therapy and 199 matched control women treated with whole-breast radiation therapy. All of the women had early-stage breast cancer and were treated with breast-conserving surgery; women were matched by age, tumor size, lymph-node status, margins of excision, estrogen receptor status, and use of adjuvant tamoxifen therapy.

After five years of follow-up, there was no difference in the median time to recurrence and rate of local recurrence between women in the two treatment groups, nor was there any difference in the rates of distant metastases, disease-free survival, overall survival, or cause-specific survival.

'These results suggest that, in appropriately selected early-stage breast cancer patients, limited-field radiation therapy may be adequate in controlling residual disease after breast-conserving therapy,' the researchers write, adding that these results raise the question of whether whole-breast radiation therapy is necessary in certain low-risk patients.

The authors point out that several phase III trials are under way in Europe to compare standard whole-breast radiation therapy with limited-field radiation therapy using different techniques and radiation schedules. 'Data from these studies will potentially provide invaluable information on the requisite volume of breast tissue requiring treatment and the range of patients appropriately managed with limited-field radiation therapy,' they write.

In an accompanying editorial, C. Norman Coleman, M.D., and his colleagues at the National Cancer Institute caution that extended follow-up will be needed to determine any late recurrences or late toxicity, which may take 10 or more years to manifest.

'Only by successfully completing a clinical trial on the equivalency of partial-breast irradiation with whole-breast irradiation can we provide definitive answers for those physicians and patients yet to face the decision about treatment options for early-stage breast cancer,' they conclude.