This is a prospective cohort study for patients diagnosed with ductal carcinoma in situ (DCIS) of the breast. The primary objective of the study is to create a de-identified database of patients, test results, treatment decisions and outcomes that can be queried to determine the utility of the DCISionRT™ test in the diagnosis and treatment of ductal carcinoma in situ of the breast.

This is a prospective cohort study conducted within the medical network of the participating investigators and institutions. Patients meeting the eligibility criteria outlined above will be eligible for participation and the investigators will obtain written informed consent. A central Institutional Review Board (IRB) will approve the protocol and each participating institution.

After diagnosis of DCIS, the most representative tissue block (or 10 sections mounted on charged slides cut at 3 microns) will be sent to PreludeDx for DCISionRT. The most representative specimen should be selected from tissue collected via direct tumor biopsy (either FNA, core needle or excisional biopsy) as part of routine patient care. Patients must be enrolled in the study and the enrollment and pre-testing data forms must be completed and submitted before the DCISionRT results are reported. Then, after review of the DCISionRT results, the investigators complete and submit the post-testing data form. The patient may then be followed for up to 10 years (or until death).

All study data will be stored in an encrypted, HIPAA-compliant database maintained by the sponsor. Each consented patient will be assigned a unique Study ID number. Study personnel at each institution will maintain a key to link the Study IDs of its own patients to the patients' local medical record number. All personal health information (PHI) will remain at the local institution and only de-identified data will be uploaded to the national registry. No genetic test results that may be used to identify the patient will be included in the database.

This study anticipates the participation of up to 150 sites within Australia with each site enrolling between 10 and 100 patients. The study is designed to collect information for up to 1,500 patients.

The purpose of this study is to create a de-identified database of patients, test results, treatment decisions and outcomes that can be queried to determine the clinical utility of the DCISionRT™ Test in the management of DCIS, as it is broadly incorporated into clinical practice. The primary objective is to identify a statistically significant difference in physician treatment recommendations for patients diagnosed with DCIS and treated with breast conserving surgery based on availability of the DCISionRT test results. The primary endpoints are treatment recommendations according to standard procedure at each clinical site both pre- and post-DCISionRT results.

Secondary endpoints include the percent of patients for which the recommended treatment before DCISionRT results and after DCISionRT results differ as a function of clinical factors, such as age groups (<40, 40-50 and >50), grade (I, II, III), and tumor size (>1cm, >2.5cm, >4cm). Other analyses involve the identification of key driver(s) of treatment recommendation, such as age, ethnicity, race, family history, presentation (screening/clinical), grade, architecture, necrosis, tumor size, palpability, number of excisions, surgical margin, hormone receptor status, HER2 status; distribution of DCISionRT scores across the cohort; and identification of key driver(s) of treatment recommendation based on geographic region of the investigator.

The study population will be selected from the clinical practices of the participating investigators and institutions. Patients who have been recently diagnosed with DCIS and are being evaluated for the need for further therapy will be screened for eligibility per the following eligibility criteria.

Inclusion Criteria:

1. A clinical decision has been made to order the DCISionRT™ Test as part of routine patient care
2. Patient must have histologically confirmed ductal carcinoma in situ (DCIS) in a single breast (presence of lobular carcinoma in situ (LCIS) or other benign breast disease in addition to DCIS is acceptable)
3. Patient must be consented within 120 days after surgery
4. Patient must be eligible for, or have already received breast conserving surgery
5. Patient must be eligible to receive radiation and/or systemic treatment
6. Patient must be female and greater than 25 years old
7. Patient must be able to provide informed consent

Exclusion Criteria:

1. Patient tissue is insufficient to generate DCISionRT test results or required DCISionRT inputs (age, tumor size, margin status, palpability) are missing
2. Patient has invasive breast cancer or evidence in the ipsilateral or contralateral breast of invasive breast cancer, including microinvasion, lymph node involvement, or Paget's disease of the nipple
3. Patient has already been surgically treated with a mastectomy for primary DCIS
4. Patient has prior in situ or invasive breast cancer

The study population will be selected from the clinical practices of the participating investigators and institutions. Patients who have been recently diagnosed with DCIS and are being evaluated for the need for further therapy will be screened for eligibility per the following eligibility criteria.

There is no current plan to govern sharing of IPD. Interested researchers should contact Principal Investigators.