SAN ANTONIO – Omitting radiotherapy after breast-conserving surgery, sentinel node biopsy, and adjuvant endocrine therapy appears safe in older patients with early breast cancer and favorable histopathology, a study presented at the 2016 San Antonio Breast Cancer Symposium (SABCS) has shown.1
“The benefit of radiotherapy in older women with endocrine responsive early breast cancer treated with breast-conserving surgery and endocrine therapy is unclear,” said Kenneth Villman, MD, PhD, Head of the Department of Oncology, Orebro University Hospital, Orebro, Sweden. “We aimed to verify if omission of radiotherapy in a predefined cohort of patients with good prognosis early breast cancer after breast conservation is safe.”
For the study, investigators analyzed data from 601 consecutive women age 65 years and older with early breast cancer from 14 Swedish centers. All patients had undergone breast-conserving surgery, had clear margins, had unifocal T1N0 and Elston grade 1 or 2 disease, and were estrogen receptor (ER)-positive. Patients had also received either tamoxifen or an aromatase inhibitor for 5 years.
After a median follow-up of 59 months, results showed that the cumulative incidence of ipsilateral breast tumor recurrence was 1.3% (95% CI, 0.6-2.7) at 5 years.
Researchers also observed 4 regional recurrences, 1 of which with ipsilateral disease recurrence; 2 distant recurrences, both of which without ipsilateral or regional recurrence; and 11 contralateral breast cancers.
In addition, 29 patients had tumors of other origin, including 7 cases of endometrial cancers. During follow-up, 39 patients died, but only 1 death was related to breast cancer and 11 were due to other cancers.
The 5-year overall survival rate was 93.9% (95% CI, 91.4-95.7).
“This study demonstrates that breast-conserving surgery and endocrine therapy without radiotherapy is a safe treatment option in women with early breast cancer and favorable histopathology age 65 years and older,” said Dr Villman. “Even though the median follow-up of 59 months is rather short, we find the cumulative incidence of ipsilateral breast tumor recurrence of 1.3% very promising.”
1. Wilman KKA, Wickberg A, Killander F, et al. Omitting radiotherapy in women ≥ 65 years with early breast cancer and favorable histopathology after breast-conserving surgery, sentinel node biopsy and adjuvant endocrine therapy is safe. Poster presented at: 2016 San Antonio Breast Cancer Symposium; December 6-10, 2016; San Antonio, TX.