To evaluate whether the use of the Oncotype DX DCIS score can guide delivery of radiation in women with low to moderate risk DCIS who have had breast conserving surgery

A prospective cohort study, conducted in Canada, to evaluate whether the use of the DCIS score changes the treatment recommended and the treatment received in women with low to moderate risk DCIS following breast conserving surgery who are candidates for radiation therapy. We plan to study 280 eligible, consenting women who will have their tumour tissue specimen sent to Genomic Health to assess their DCIS score.

At each centre, all patients with DCIS referred to radiation oncology will be documented. When a physician identifies an eligible patient, the patient will be approached by the referring physician or delegate to voluntarily provide informed consent to participate in this study. Consenting patients will be registered through the Ontario Clinical Oncology Group's (OCOG) web-based registration system. Data related to the patient demographics, surgery details, and tumour characteristics will be collected. The preliminary treatment recommendation and patient preference for treatment will be documented. Patient Decisional Conflict will be documented by the patient using the Decisional Conflict Scale (DCS). The patient's tumour specimen will be sent for analysis to Genomic Health. DCIS score results will be sent to the referring physician. OCOG will also receive the DCIS score results. The final treatment recommendation, patient preference, and treatment received by the patient will be documented. Patient decisional conflict will be documented by the patient using the DCS. The study data will be verified by source documentation.

Inclusion Criteria:

(1) Women with newly diagnosed breast cancer treated by definitive surgery with histological evidence limited to DCIS.

Exclusion Criteria:

1. Age < or = 45;
2. Treated by mastectomy;
3. Surgical margins of <1mm;(re-excisions may be performed where results are regarded as clear margins, these cases will not exclude patients);
4. Tumour size >2.5cm;
5. Any invasive breast cancer including micro invasion;
6. Histological evidence of multifocality (defined as having more than one distinct focus of DCIS with >5mm of intervening benign breast tissue in one quadrant of the breast);
7. Any associated lobular carcinoma in situ;
8. Previous diagnosis of ipsilateral invasive carcinoma or DCIS of the breast;
9. Any contraindication for whole breast irradiation such as chronic heart or lung disease or previous ipsilateral chest wall radiotherapy;
10. Physician/patient unwilling to comply with study protocol; and
11. Inability to provide informed consent (e.g. dementia or severe cognitive impairment).

Prospective cohort study conducted in Ontario in women with a low to moderate risk DCIS following breast conserving surgery who are candidates for radiation. Eligibility status should be confirmed by the referring physician or delegate prior to enrollment. It is important that no exceptions are made to the eligibility criteria. Questions related to eligibility requirements and/or specific criteria should be addressed with OCOG prior to enrollment

Genomic Health will provide results to referring physician, OCOG will have access to results