Despite clinical trial evidence and recommendations that certain older breast cancer patients can forego radiation therapy after lumpectomy, most older patients continue to receive radiation therapy, according to a new study.
Despite clinical trial evidence and recommendations that certain older breast cancer patients with small tumors forego radiation therapy after lumpectomy, most of these older patients continue to receive radiation therapy, according to a study published in the Journal of the American College of Surgeons.
The study found that radiotherapy use decreased only slightly, from 68.7% to 65.8%, in women 70 years of age or older with stage I, estrogen receptor–positive breast cancer following publication of the Cancer and Leukemia Group B (CALGB) 9343 phase III trial, which showed that adjuvant radiation therapy is not necessary for these women. This trial prompted a recommendation from the National Comprehensive Cancer Network (NCCN) against radiation therapy for this subset of breast cancer patients. The results of the trial have since been confirmed in a 10-year follow-up analysis.
Quyen D. Chu, MD, MBA, FACS, professor of surgery at Louisiana State University Health Sciences Center in Shreveport, Louisiana, and colleagues analyzed 205,860 women aged 70 years or older diagnosed with breast cancer between 1998 and 2012 who underwent lumpectomy for their estrogen receptor–positive, stage I breast cancer. About half of the women received their diagnosis prior to publication of the CALGB 9343 trial in 2004.
Women more likely to not receive radiotherapy were older than 85 years of age, treated at an academic research facility, had an increased great circle distance, a high comorbidity index, a small tumor size, well-differentiated histology, residual tumor, or did not receive anti-hormonal therapy. Insurance status and education level had no significant impact on use of radiation therapy.
Radiation therapy is an important part of the treatment of breast cancer with data from prospective phase III clinical trials supporting the use of radiation along with breast-conserving surgery to reduce the risk of local recurrence and distant metastases, while also improving survival.
The CALGB 9343 clinical trial identified a subset of patients who did not benefit from adjuvant radiation therapy, however-specifically, women 70 years of age and older with stage I, estrogen receptor–positive breast cancer (≤ 2 cm) that has not spread to the lymph nodes, who have had a lumpectomy, have negative surgical margins, and have received at least 5 years of anti-hormone therapy such as tamoxifen.
There are many potential reasons for the relatively poor adoption of the recommendation. Poorer access to cancer care, rather than better adherence to the guideline, may explain some differences observed in radiation therapy use, Chu said in a statement. Women may also have opted for radiation therapy to reduce their worrying about disease recurrence, according to the study authors.