A Prospective Cohort Study to Evaluate the Oncotype DX® Test in Early Stage Breast Cancer
A Prospective Cohort Study to Evaluate the Oncotype DX® Test in Early Stage Breast Cancer
A prospective population-based cohort study is being conducted in Ontario to evaluate whether
 the performance of Oncotype DX® changes the treatment recommended and the treatment received
 in women or men with node negative, ER positive breast cancer who are receiving (or will
 receive) endocrine therapy and who are candidates for chemotherapy. One thousand eligible
 consenting women and men will have their tumor tissue specimen sent to Genomic Health where
 the Oncotype DX® assay will be performed.
The evidence supporting the adoption of Oncotype DX® is relatively weak by the criteria used
 by the Ontario Health Technology Advisory Committee (OHTAC). There is only one small
 published prospective study that reports on Oncotype DX® changing clinical management. The
 economic models that estimated the potential advantages of using an Oncotype DX® guided
 treatment strategy may have overestimated the benefits because they assumed that all patients
 with tumors >1cm in the absence of Oncotype DX® testing would receive chemotherapy in
 addition to tamoxifen, and that the magnitude of benefit with chemotherapy over tamoxifen is
 relatively large, i.e. reduces recurrence risk by 74% and associated with an absolute benefit
 of 28%. (The benefit comes from one trial and is applied to all patients). It is estimated
 that there are about 3,300 incident cases with node negative, ER positive, HER2 neu negative
 tumors annually in Ontario, it is important to evaluate the adoption of this test for
 decision making in Ontario.
Inclusion Criteria:

 -  Women or men with histologic evidence of invasive breast cancer (ductal, lobular or
 mixed disease).

 -  Surgical resection including breast conserving surgery or modified radical mastectomy
 or simple mastectomy, within the last four months.

 -  Axillary lymph nodes assessed for tumor by:

 (i) sentinel node biopsy, or (ii) axillary node dissection, or (iii) both

 -  Axillary lymph node assessment negative for cancer, or positive only for
 micrometastases (i.e., cancer <2mm by H&E stain).

 -  Tumor is estrogen receptor (ER) positive.

 -  Receiving or to receive adjuvant endocrine therapy (i.e., tamoxifen or aromatase
 inhibitor).

 -  Being considered for adjuvant chemotherapy.

 Exclusion Criteria:

 -  Axillary lymph node positive for cancer.

 -  Patients with inoperable locally advanced breast cancer.

 -  Metastatic breast cancer, including local ipsilateral recurrence.

 -  HER2 neu positive.

 -  Physician/Patient unwilling to comply with study protocol.

 -  Inability to provide informed consent (e.g. dementia or severe cognitive impairment).