In a patient with ER+/HER2- breast cancer, do you ever use Oncotype testing to assist in decision-making regarding adjuvant chemotherapy when the tumor size is less than 0.5 cm, or when there are positive lymph nodes?  

The NSABP and other data that was approved for prognostication and for prediction of benefit with chemo excluded 5 mm or smaller tumors. In practice, oncologists would not offer chemo for ER positive and node negative tumors that are 5 mm or less in size . Thus, I would not do oncotype do testing. ...