T1 G1 NO ER positive breast cancer—adjuvant therapy is needed

Aims To assess the outcome of treating patients with excellent prognosis (T1 G1 N0 ER +ve) breast cancers with breast conserving surgery alone. Methods One hundred and twenty-one women with grade 1, node negative, ER+ tumours, smaller than 20 mm who were treated by breast conserving surgery alone between 1991 and 2000. Margin width was always at least 5 mm. The following were recorded: local recurrence (LR), distant recurrence, new contra-lateral primaries and death. Recurrence rates were then compared to those in the largest series. Results One hundred and twenty-one women were followed up for a median of 68 months. Fourteen developed further breast cancer in the same side and eight new cancers in the contra-lateral breast. There was one case of distant metastasis and no deaths. Local recurrence rate was significantly higher than other studies (p=0.006). Conclusions Although there is no detrimental effect on survival after this length of follow-up, the omission of radiotherapy and tamoxifen appears to increase the probability of LR. Patients with T1 G1 N0 ER+ breast cancer treated by breast conserving surgery should be offered both radiotherapy and tamoxifen.