Purpose: The effectiveness of radiation therapy (RT) in reducing local recurrence after breast-conserving surgery (BCS) in unselected patients with early stage invasive breast cancer has been demonstrated in multiple randomized trials. Whether a subset of women can achieve local control without RT is unknown. In 1986, we initiated a prospective one-arm trial of BCS alone for highly selected breast-cancer patients. This report updates those results.
Methods and materials: Eighty-seven (of 90 planned) patients enrolled from 1986 until closure in 1992, when a predefined stopping boundary was crossed. Patients were required to have a unicentric, T1, pathologic node-negative invasive ductal, mucinous, or tubular carcinoma without an extensive intraductal component or lymphatic-vessel invasion. Surgery included local excision with margins of at least 1 cm or a negative re-excision. No RT or systemic therapy was given.
Results: Results are available on 81 patients (median follow-up, 86 months). Nineteen patients (23%) had local recurrence (LR) as a first site of failure (average annual LR: 3.5 per 100 patient-years of follow-up). Other sites of first failure included 1 ipsilateral axilla, 2 contralateral breast cancers, and 4 distant metastases. Six patients developed other (nonbreast) malignancies. Nine patients have died, 4 of metastatic breast cancer and 5 of unrelated causes.
Conclusions: Even in this highly selected cohort, a substantial risk of local recurrence occurred after BCS alone with margins of 1.0 cm or more. These results suggest that with the possible exception of elderly women with comorbid conditions, radiation therapy after BCS remains standard treatment.