Staging, grading and cell type

The stage of a cancer describes its size and whether it has spread to other parts of the body. DCIS can be any size but is always stage 0 because it hasn’t spread into surrounding breast tissue.

The grade of a cancer describes how the cells look and how quickly they grow compared to normal cells. The grade of DCIS is important as it describes how likely it is to come back or develop into invasive breast cancer. There are three grades of DCIS: low-grade, moderate or intermediate-grade, and high-grade.

Doctors grade DCIS by looking at cells from your biopsy under a microscope. DCIS cells are either comedo or non-comedo. Comedo cells are fast-growing, which means they are high-grade. Non-comedo cells are slow-growing, which means they are low- or moderate-grade.

The cells will also be tested for oestrogen receptors as the oestrogen hormone can help the cancer cells to grow.

Knowing the grade and type of the DCIS cells helps your doctors plan the best treatment for you.

Staging of DCIS

In breast cancer, DCIS is described as stage 0. This is the earliest stage and means there is no invasive breast cancer (it hasn't spread into surrounding breast tissue). DCIS can be of any size but it's still always stage 0.

Grading of DCIS

The grade of a cancer describes how the cells look compared with normal cells and how quickly they grow. In DCIS, the grade of the cells is important. It shows how likely DCIS is to come back in the breast, or to develop into an invasive cancer.

There are three grades: low-grade, moderate- or intermediate-grade, and high-grade.

Low-grade DCIS

The cells look similar to normal cells or to cells seen in a benign condition known as atypical ductal hyperplasia. This is where cells are being over produced (hyperplasia) but they are only slightly abnormal or atypical.

Moderate- or intermediate-grade DCIS

The cells grow faster than normal cells and look a little less like normal cells.

High-grade DCIS

The cells grow more quickly and look quite different from normal breast cells.

High-grade DCIS is more likely to come back or develop into an invasive cancer than low-grade DCIS. Low-grade DCIS can still develop into invasive cancer, but this would usually take many more years than for a high-grade DCIS.

Knowing the grade of the DCIS helps your doctors to decide on the best treatment for you.

DCIS with microinvasion

The pathologist will examine the tissue closely to see if there are areas where the cells have just started to spread through the duct walls. These very small areas are called microinvasions.

Cell type

The breast cells in DCIS also have a particular appearance and pattern that can be seen when they’re looked at under the microscope. The cells can be classified as either comedo or non-comedo.

Comedo cells are fast-growing (high-grade) cells. Because the cells grow quickly, they don’t get enough nourishment and die off, leaving a build-up of dead cells in the middle of the duct.

Non-comedo cells are not fast-growing, so there aren’t areas of dead cells in the ducts. This means non-comedo DCIS is low- or moderate-grade.

Hormone receptors

Some DCIS cells have receptors on them that allow hormones, such as oestrogen, to attach to the cancer cell. These hormones can help the cancer cells to grow. The tissue that’s removed is tested to see if it has oestrogen receptors. If it does, it’s known as oestrogen-receptor positive (ER positive) breast cancer. If your tests show the DCIS is ER positive, you may be given treatment with hormonal therapy.

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Treatment overview

Most women will have surgery to remove the cancer. You may also have other treatments to reduce the risk of it coming back.