BOSTONEven in a highly selected group of patients with stage I breast cancer, there is a substantial and long-term risk of local recurrence following treatment with conservative surgery without radiotherapy or systemic therapy, May Lim, MD, reported at a general session of the San Antonio Breast Cancer Symposium.
There is a subset of women who have a low rate of local recurrence following conservative surgery and radiotherapy, but the question has remained as to whether treatment with conservative surgery alone could achieve adequate local control in this group of patients, said Dr. Lim, of the Joint Center for Radiation Therapy, Harvard Medical School.
The 81 patients analyzed in this single-arm, prospective trial all had small T1 tumors (median pathologic size, 0.9 cm), histologically negative axillary lymph nodes, no distant metastases, no extensive intraductal component, no lymphatic vessel invasion, wide excision with negative margins of 1.0 cm or greater, and no adjuvant radiation or systemic therapy. Median age was 66 years; 75% of tumors were detected by mammography alone.
Although these patients were considered to have a good prognosis, at a median follow-up of 92 months, 19 of 81 patients (23%) have had a local recurrence. Time to local recurrence was 7 to 135 months, with a median of 35 months (see Table,).
Other sites of first failure include two patients with contralateral breast cancer, one with ipsilateral axillary node failure, and four with distant metastases. The average annual rate of local recurrence is 2.8 per 100 patient-years of follow-up, and for overall breast cancer recurrence, 3.8 per 100 patient-years of follow-up. Thus far, nine patients have died, four of metastatic breast cancer and five of unrelated causes.
The implication is that a subgroup of low-risk patients in whom radiation can safely be omitted has not been clearly identified, Dr. Lim said.