Staging, grading and cell type of DCIS
The stage of a cancer describes its size and whether it has spread. The grade of a cancer describes how the cells look compared with normal cells.
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 spead into surrounding breast tissue). DCIS can be of any size but it's still always stage 0.
The grade of a cancer describes how the cells look compared with normal cells. 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.
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 overproduced (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.
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 decide on the most appropriate 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.
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.
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 may be 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 that the DCIS is ER positive, you may be given treatment with hormonal therapy.