DCIS doesn’t usually appear as a breast lump or breast change. As a result, most women with DCIS do not show any signs or symptoms of having breast cancer.

Occasionally, you may feel or notice a lump, or there may be some discharge from the nipple. It is important to discuss any changes in your breasts with your doctor.

Getting your diagnosis of DCIS can take a little while as you may need several tests. This is a time of uncertainty and anxious waiting. 

How DCIS is usually diagnosed

The most common ways people are diagnosed are through:

• mammograms (a low-dose X-ray of the breasts)
• ultrasound scan.

This may be during routine breast screening or if scans are done for another reason.

If these tests show possible DCIS, doctors will want to understand how much disease is present, and what level or grade. They may recommend more tests or a biopsy to make the diagnosis.

The most common way DCIS is noticed is on a mammogram. The mammogram may show tiny white dots called ‘calcification’. These are calcium salts and they are common.

Some calcification is normal, not cancer (‘benign’) and does not require removal or treatment. Other calcification is abnormal and you may need surgery to remove it. 

Not all DCIS shows up as calcification. Sometimes, a mammogram or ultrasound shows other abnormal changes such as a mass-like appearance.

Some DCIS is not visible at all on a mammogram.

The mammogram shows different views of the breast. The side view (‘mediolateral oblique or MLO) and the top-to-bottom view (‘craniocaudal’ or CC) allows most breast tissue to be seen.

Tests to confirm a DCIS diagnosis

If a mammogram shows changes that may be DCIS, doctors will want to do tests to confirm the diagnosis.

There are several possible tests and procedures. This means that a final diagnosis may take a while as more test results come in.

Imaging tests

You may have another mammogram or an ultrasound to see the area of calcification in more detail. Sometimes you may need an MRI scan to see:

• how much DCIS is present
• if the DCIS has spread into the surrounding tissue (invasive breast cancer).

Biopsy

Doctors will want to take samples of affected breast tissue so they can be reviewed by a pathologist. They use the mammogram or ultrasound as a guide, to take the sample from the exact area of calcification or breast abnormality.

The biopsy may be:

• a core needle biopsy (CNB)
• vacuum assisted biopsy needle (VAB).

It is not always easy to confirm a diagnosis of DCIS from a biopsy. This is because a range of cell changes can be present in the ducts.

These vary from very small changes in a small number of cells around the walls of the duct to significant changes that block the entire duct.

If the doctor cannot accurately classify the DCIS, you may need more procedures such as another biopsy or surgery to make a final diagnosis.

Procedures to locate the DCIS before surgery 

A small procedure during a biopsy or before surgery can help the surgeon find the right spot when they operate on the DCIS. This can show (‘mark’) the borders or margins of the DCIS.

Several different types of markers can be used.

Hookwire

This is the most common procedure used to mark the area of the tissue that needs to be removed. The hookwire is a very thin wire with a tiny hook at the end. It is inserted into the breast, with its end at the place the abnormal tissue was found. The hook keeps the wire in the right place.

The procedure usually happens in an X-ray department or private radiology clinic. A radiologist inserts the wire using a mammogram or ultrasound as a guide. 

Metal marker

During a biopsy, a small metal clip (or marker) may be put in the breast where the tissue samples are taken. This makes it easier to find the area again if another biopsy or surgery is needed. It is safe to leave the clip in the breast.

It does not need to be removed, even if you do not have any more procedures.

Radioactive seed

Instead of using a hookwire or marker, some hospitals insert a very low dose radioactive seed or a magnetic seed into the breast tissue. The seed is tiny – less than 5mm long, about the length of a sesame seed – and is made of metal. This procedure can be done up to two weeks before your surgery.

During surgery, a special probe finds the seed. This guides the surgeon to the tissue they need to remove, along with the seed.

Carbon tracking

Another procedure uses a small amount of carbon (‘charcoal suspension’) to guide the surgeon.

Under ultrasound or mammography, a needle is injected into the site of the lesion. As the needle is removed, it leaves behind a track or trail of carbon. This directs the surgeon to the tissue they need to remove.