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Clinicians continue to treat older women with breast radiation despite lack of survival advantage
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Many radiation oncologists and surgeons use adjuvant radiotherapy to treat older women with early-stage breast cancer, despite no evidence showing a survival advantage for this approach, according to a survey published in Annals of Surgical Oncology.
“The addition of radiotherapy decreases the chance that the cancer will come back, but does not seem to affect how long patients live,” Dean A. Shumway, MD, assistant professor of radiation oncology at Michigan Medicine at University of Michigan, told HemOnc Today. “We wanted to understand more about the underlying reasons that many older women continued to receive radiotherapy when they have the option of omitting it.”
Although radiotherapy has long been considered a key component of breast-conserving therapy and has been shown to cut recurrence rates in half, the absolute benefit in women aged 70 years or older with stage I, ER-positive tumors is small.
A 2004 study published in The New England Journal of Medicine showed that among women aged 70 years or older who had early, ER-positive breast cancer, the addition of adjuvant radiation therapy to tamoxifen did not significantly decrease the rate of mastectomy for local recurrence, increase the survival rate, or increase the rate of freedom from distant metastases. The study suggested tamoxifen alone was a reasonable choice for adjuvant treatment.
In their study, Shumway and colleagues surveyed a national sample of 713 radiation oncologists and 879 surgeons. Of those, 452 surgeons (mean age, 52.2 years; 63.8% men) and 373 radiation oncologists (mean age, 49.8 years; 63.3% men) responded.
Researchers assessed responses to clinical scenarios, knowledge of pertinent risk information, and correlates of views on radiation omission.
Forty percent of surgeons and 20% of radiation oncologists reported it was unreasonable to omit radiotherapy in women aged 70 years or older with stage I, ER-positive breast cancer following lumpectomy and endocrine therapy. Additionally, 29% of surgeons and 10% of radiation oncologists erroneously reported radiotherapy improved survival for older women.
Thirty-two percent of surgeons and 19% of radiation oncologists overestimated the risk for locoregional recurrence with the omission of radiotherapy among older women.
Moreover, when presented with a scenario of an 81-year-old woman with early-stage breast cancer and multiple comorbidities, 31% of surgeons and 35% of radiation oncologists said they would still recommend radiotherapy.
“Our study found that many surgeons and radiation oncologists felt that omitting radiotherapy was a departure from the standard of care,” Shumway said. “Some tended to overestimate the benefits obtained from radiotherapy in this group of older patients with favorable-prognosis breast cancer.
“It also is important to acknowledge that the decision to omit radiotherapy is ultimately the patient’s choice,” Shumway added. “A majority of the clinicians in our study reported that patients frequently desire maximal treatment, even if the benefit is very small.”
Most older women with early-stage breast cancer die of medical conditions other than their breast cancer, Shumway noted, adding that many oncologists wonder if the omission of radiotherapy could be an option in women aged younger than 70 years.
A study sponsored by University of Michigan Cancer Center is recruiting women for its Individualized Decisions for Endocrine Therapy Alone (IDEA) trial, which is assessing the safety and efficacy of omitting radiotherapy among postmenopausal women aged 50 to 69 years who have a favorable genomic score (Oncotype DX [Genomic Health] score of 18 or lower). Those women would receive endocrine therapy alone following lumpectomy.
“Omitting radiotherapy in younger patients is an ongoing area of investigation,” Shumway said. “The general trend that I see is that less really is more, and we are becoming more able to identify women with a favorable prognosis who have a similarly excellent outcome with less intensive treatment.”
It is equally important to learn whether substituting radiotherapy for endocrine therapy might provide clinicians with another option for women with early-stage breast cancer, Shumway said. Commonly reported adverse events associated with endocrine therapy include hot flashes, tiredness, insomnia or other sleep problems, headaches, loss of appetite, upset stomach or vomiting.
“Many women experience side effects with endocrine therapy, and approximately half of women have difficulty completing a 5-year course,” Shumway said. “There is evidence to suggest that the outcome might be similar whether patients omit radiotherapy or endocrine therapy. There may be many older women with early-stage breast cancer who would prefer to have 3 weeks of radiotherapy and be done with it, rather than continue a medication every day for 5 years when there can be meaningful side effects.” – by Chuck Gormley
For more information:
Dean A. Shumway, MD, can be reached at dshumway@umich.edu.
Additional references:
Aiello Bowles EJ, et al. J Oncol Pract. 2012;doi:10.1200/JOP.2012.000543.
Hughes KS, et al. J Clin Oncol. 2012;doi: 10.1200/JCO.2012.45.2615.
Hughes KS, et al. N Engl J Med. 2004;doi:10.1056/NEJMoa040587.
Disclosures: The Conquer Cancer Foundation, Breast Cancer Research Foundation, Cancer Surveillance and Outcomes Research Team, and NCI funded this study. The authors report no relevant financial disclosures.