Also called intraductal carcinoma, ductal carcinoma in situ (DCIS) is a type of breast cancer referring to the presence of deviant or irregular cells lining a breast’s milk ducts. DCIS is non-invasive in nature, which means the cancer is within the milk duct and has not attacked other portions of the breast. However, if the cancerous cells are kept untreated for long, they could eventually break via the duct and move to surrounding tissues, transforming into an invasive type. Generally, DCIS is treated through non-invasive methods such as radiation. Surgery is usually not the first resort.
The possibilities of DCIS returning post treatment are fairly high at an estimated 20-30 percent; the recurring cancer could be noninvasive or invasive. Also, there are risks of cancer developing in the other breast. Typically, the recurrence percentage is higher among younger patients.
DCIS can be categorized, primarily depending on the tumor’s appearance and location. Generally, DCIS is classified based on how different the affected cells look from regular breast cells and their speed of growth. DCIS could be graded as:
- Low: Also referred to as low mitotic rate or nuclear grade 1, the cancer cells in this grade don’t look much different from regular breast cells and recurrence post-surgery is highly unlikely.
- Intermediate or moderate: Also known as intermediate mitotic rate or nuclear grade 2, this DCIS grade happens to have cells that look slightly different from normal cells and their growth rate is slow just like low-grade DCIS.
- High: Also known as high mitotic rate or nuclear grade 3, the cancer cells in this DCIS grade appear significantly abnormal, have a much faster growth rate, and are extremely likely to show up after surgery.
There are different low- and moderate-grade DCIS patterns such as:
- Papillary DCIS: The affected cells have a finger-like arrangement inside the milk ducts. In case the cells are extremely small in size, they are referred to as micropapillary.
- Cribriform DCIS: In this case, gaps exist between cancer cells within the infected breast ducts.
- Solid DCIS: The infected breast ducts are completely filled with the cancer cells.
Causes & Risk Factors
Like other types of breast cancer, no specific factor could be held responsible for causing DCIS. Generally, it’s likely due to multiple factors such as genes, lifestyle and environment. Certain factors that could increase DCIS risks are age, personal breast cancer history, familial history, first pregnancy after 30 years of age, obesity, etc. Women falling in the 50-59 years age group are likely to fall prey to DCIS.
Usually, there are no distinct DCIS symptoms. But certain signs such as bloody nipple discharge, breast lump, thickened region below the breast skin, etc. are possible in some affected women.
Diagnosis & Testing
DCIS is typically detected during a mammogram, which is carried out as part of regular breast cancer screening. On a mammogram, DCIS cancer cells usually appear in small clusters with the cells having irregular sizes and shapes. A diagnostic mammogram that views the cells at increased magnification could be done, to ascertain if the abnormal cells are truly worrisome and whether there’s a need to examine both breasts. In case further diagnosis is needed, the next phase of testing would entail breast biopsy and ultrasound.
Breast tissue samples could be harvested for further testing. The sample removal could be done through one or multiple breast biopsy procedure types such as core needle biopsy, stereotactic biopsy, and surgical biopsy. The core needle and stereotactic techniques entail usage of a needle – smaller breast tissue samples are removed. In case either of the two biopsy techniques indicate DCIS presence, surgical biopsy (wide local excision) would be carried out for further analysis.
DCIS isn’t fatal or life-threatening. However, as aforementioned, treatment is required to ensure the condition doesn’t turn invasive. Generally, radiation and lumpectomy (breast-conserving surgery) are used to effectively treat the cancer. A simple mastectomy could also be performed. The treatment for DCIS turns out successful almost always. Lumpectomy is performed when a smaller area is affected with DCIS, which also means the requirement for a breast reconstruction surgery is almost zero.
Mastectomy is resorted to if the DCIS-affected area is large or if there are multiple regions impacted by DCIS. Both these conditions mean additional tissues have to be removed. Also, if the patient is not the ideal candidate for radiation therapy, a mastectomy would be the only way out. Radiation is usually administered post lumpectomy. An ideal candidate is someone who is not in her first pregnancy trimester, has not received radiation to the breast or chest before, and is not sensitive to the therapy’s side effects.