Radiation Does Not Improve Survival in Elderly Early-Stage Breast Cancer Patients

Roxanne Nelson

May 26, 2010

May 26, 2010 — Adjuvant radiation therapy might not be necessary for older women with early-stage breast cancer who undergo lumpectomy. Women 70 years or older with early-stage disease who have a lumpectomy and also receive tamoxifen can safely forego radiation therapy because it does not appear to affect survival, distant disease-free survival, breast-cancer-specific survival, or breast conservation, a new study concludes.

At 10 years, the breast-cancer-specific survival for women who received tamoxifen was 98%, compared with 96% for those who received tamoxifen and radiation. Those who received tamoxifen only had a 10-year overall survival of 63%, compared with 61% for women who also received radiation therapy.

"We found that radiotherapy did have some benefit in terms of in-breast recurrence, but those benefits were relatively small," said Kevin S. Hughes, MD, from the Department of Surgery at Massachusetts General Hospital in Boston, at a press briefing held in advance of the American Society of Clinical Oncology (ASCO) 2010 Annual Meeting. The study will be presented on June 7.

"You can get about a 6% reduction in in-breast recurrence with the addition of radiation, but it has no impact on the ultimate ability to preserve the breast, no impact on distant metastases, no impact on breast-cancer-specific morality, and no impact on overall survival," he said.

The results are . . . certainly practice affirming and may be potentially practice changing.

Douglas W. Blayney, MD, president of ASCO, said the results of this study are "certainly practice affirming and may be potentially practice changing."

From his own experience and the experiences of his colleagues, Dr. Blayney noted that many older women in this group often elect to forgo radiation when they understand the small benefit. These results "give us some comfort as physicians in supporting that decision on our patients' behalf, and that may change the recommendation we make to our patients," he added.

No Survival Benefit With Added Radiation Therapy

The current study is a follow up to an earlier analysis of this trial, which showed that after a median follow-up of 7.9 years, tamoxifen alone was an effective alternative to tamoxifen and radiation. This new analysis includes follow-up data after 10.5 years.

The study involved 636 women who were 70 years of age or older with clinical stage I, node-negative, estrogen-receptor (ER)-positive breast carcinoma who had undergone lumpectomy. They were randomized to receive tamoxifen plus radiation therapy (n = 317 women) or tamoxifen alone (n = 319 women). The primary end points of the study were time to locoregional recurrence, mastectomy for recurrence, distant metastases, breast-cancer-specific mortality, and all-cause mortality.

There was a small benefit for radiation therapy in only 1 of the end points, Dr. Hughes explained. Patients who received tamoxifen plus radiation had an absolute 6% reduction in ipsilateral breast tumor recurrence, compared with those who received tamoxifen alone. "Essentially, we would have to irradiate 319 women to prevent 20 in-breast recurrences, which is a fairly small benefit," he said.

Otherwise, the remaining end points did not differ between the 2 cohorts (P > .05). The probability of being free from mastectomy at 10 years was 96% for tamoxifen only and 98% for tamoxifen plus radiation; being free from distant metastases was 95% and 93%, respectively.

The 10-year breast-cancer-specific survival was also similar between the 2 groups: 98% for tamoxifen only and 96% for the tamoxifen plus radiation. Overall survival was 63% and 61%, respectively.

Feasible to Avoid Radiation

Dr. Hughes pointed out that 43% of the patients in this study have died, but this was an older population and almost none of the deaths were due to breast cancer. "Only 12 women died in the radiation group died from breast cancer and only 8 in the tamoxifen group, so the majority died of other causes," he explained.

These findings demonstrate that after more than 10 years of follow-up, lumpectomy with antiestrogen therapy alone can be an appropriate treatment option for this population. "The question now becomes whether tamoxifen is enough treatment for women aged 70 and older with these small-stage, ER-positive tumors," said Dr. Hughes. "This means discussing it with patients, but I think avoiding radiation in this group is very feasible."

The study was funded by the National Cancer Institute. The authors have disclosed no relevant financial relationships.

American Society of Clinical Oncology (ASCO) 2010 Annual Meeting: Abstract 507. To be presented June 7, 2010.


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