Would you recommend observation for an early stage, low grade, ER+, pure tubular carcinoma of the breast after lumpectomy with negative margins for women younger than 65?  

We have data in this subset of patients from BASO II. Essentially, the risk of 10-yr LRR was ~20% with nothing, 8% with endocrine tx or RT, and 2% with both. When I treat these patients, I give 40.05 Gy no boost. External beam APBI like IMPORT LOW seems quite reasonable. I would happily enroll the...