The role of radiotherapy in treating small early invasive breast cancer

Abstract Aim The aim of the study was to identify if radiotherapy can be safely avoided in a selected subgroup of largely screening detected small invasive breast cancer. Methods One hundred and eighty-eight patients with node negative invasive early breast cancer ≤1 cm (≤T1b) treated in our centre between 1990 and 2004 were retrospectively followed for local, regional and distant recurrences. Treatment involved adequate local excision by breast conserving surgery (BCS). Axillary staging was performed by a four node axillary sampling until 2000, following which sentinel lymph node sampling was employed. All sections were assessed histologically by haematoxylin and eosin stained sections. The inked margins were reported as being involved, close and clear. Radiotherapy (RT) was employed only if the resected margins were inadequate, and in those with involved axillary nodes who refused further completion axillary clearance. Results Ninety-four patients (Group A) had BCS alone and 79 patients (Group B) had both BCS and RT. There was no ipsilateral breast tumour recurrence (IBTR) in 88 patients in Group A, corresponding to an actuarial freedom from IBTR of 96%, 91% and 88.1% at 5 years, 8 years and 9 years. In Group B, there was no IBTR in 75 patients corresponding to an actuarial freedom from IBTR of 97%, 94.9% and 90.6% at 5 years, 8 years and 10 years. Conclusion Our experience over 14 years has shown that it is possible to safely avoid radiotherapy in a selected subgroup of small invasive breast cancer.