Ductal carcinoma in situ (DCIS) is not breast cancer as we commonly understand it, because it has not spread outside the milk ducts into other parts of the breast, or to other parts of the body. Without treatment, DCIS may develop into invasive breast cancer, which can spread outside the ducts and possibly to other parts of the body.

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The pathology report

After a biopsy or breast surgery, the cells or tissue are sent to a pathologist. The pathologist looks at the cells or tissue under a microscope and writes the results in a pathology report. This will usually take a couple of days. Information in the pathology report helps with treatment planning.

Information in the pathology report is used to determine the stage of breast cancer. The stage used to describe DCIS is Stage 0.

Some women find it helpful to keep a copy of their pathology report so that they can refer to it later.

What does the DCIS pathology report mean?

The DCIS pathology report contains important information about a woman’s DCIS that is used to decide on treatment recommendations.

Some of the information in the pathology report will only be available after breast surgery.

The pathology report usually includes the following information:

• Size and location
  The report shows the size of the DCIS and where it is in the breast. This will affect what treatments are recommended, including the type of surgery.
   
• Surgical margin
  During a surgical biopsy or breast conserving surgery, the surgeon removes the DCIS and an area of healthy looking tissue around the DCIS. The healthy looking tissue is called the surgical margin. If there are no DCIS cells in the surgical margin, it’s likely that all the DCIS has been removed. In this case, the surgical margin is said to be ‘clear’. If the surgical margin is not considered to be ‘clear’, more surgery may be required to ensure that all of the DCIS is removed.
   
• Grade of DCIS
  The grade of the DCIS shows how fast the abnormal cells are growing. DCIS grade is numbered from 1 to 3. A low grade (Grade 1) means that the DCIS is growing slowly. A high grade (Grade 3) means that the cancer is growing more quickly.
   
• Hormone receptors
  The report may show whether the DCIS cells are positive or negative for hormone receptors. This will affect whether hormonal therapies are recommended.

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