Research explores impact of radiotherapy in older women with low risk of breast cancer recurrence

A Rhode Island Hospital radiation oncologist says in a new editorial that research exploring the impact of radiotherapy in older women with low risk of breast cancer recurrence has little effect on actual clinical decisions. The editorial written by David E. Wazer, M.D., chief of the department of radiation oncology, is published in the current issue of the Journal of Clinical Oncology.

Breast-conserving therapy (BCT) has shown to have comparable outcomes to mastectomy, allowing women to preserve their breast without compromising their chance of being cured of cancer. BCT also has been associated with improved quality of life, as compared to mastectomy. Radiation therapy is an integral part of BCT, and its benefit is clearly dependent on the baseline risk of ipsilateral breast tumor recurrence (IBTR) after surgical excision alone, and is small in patients at low risk of recurrence. Multiple trials have shown that the IBTR risk decreases with age, and has prompted analysis of the benefit of radiotherapy for older patients with breast cancer.

"If an older patient has been treated for breast cancer, and has a low risk of recurrence, there may be no clinical reason to subject them to radiation therapy," Wazer said. "It's simply not necessary -- it will not improve their quality of life, nor increase their chance of survival."

Wazer references the Cancer and Leukemia Group B 9343 trial that demonstrated that radiotherapy has no discernable benefits as measured by either mastectomy free (MFS) or overall survival in a highly selected group of patients age 70 or older with estrogen receptor (ER) positive tumors who received five years of tamoxifen.

Despite evidence to support this finding, a recent Surveillance, Epidemiology and End Results (SEER) -Medicare database analysis showed that this data has minimal impact on clinical decisions, suggesting that oncologists perceive meaningful differences between patients treated in routine clinical practice as compared with those enrolled in clinical trials.

"True, there are factors to the SEER-Medicare database analysis that could raise eyebrows," Wazer said. "For example, in the absence of direct data related to the incidence of IBTR, the authors were compelled to use billing codes as surrogates for clinical events, meaning the same mastectomy billing code recorded as indicative of tumor recurrence could be reflective of an entirely unrelated event."

Wazer continued, "But oncologists must look at the big picture. Will the radiation therapy truly help that patient in her 70s who is at a very low risk of tumor recurrence? Not likely. It is perplexing to see that despite high-quality clinical trial evidence supporting the omission of breast radiotherapy in select older patients, the pattern of clinical practice in the United States seem to show little change."

Source: Lifespan