A Comprehensive Overview of Ductal Carcinoma In Situ (DCIS)

Ductal carcinoma in situ (DCIS) is a type of breast cancer that is considered non-invasive or pre-invasive. This occurs when the healthy cells within the milk ducts of the breast transform into cancerous cells and begin to rapidly multiply. However, this type of cancer has not penetrated the outermost wall of the breast ducts, known as the ductal basement membrane, and has not affected the surrounding breast tissue.

It is considered an early stage of cancer and generally carries a favorable prognosis if treated promptly and appropriately. However, if left untreated or undetected, it can potentially develop into a more serious and advanced form of breast cancer. It is important to receive regular breast cancer screenings and seek medical attention if any concerning symptoms arise.

DCIS is classified as a stage 0 cancer as the atypical cells have not spread outside of the ducts.

DCIS accounts for about 20% to 25% of all newly diagnosed cases of breast cancer in the United States and about 17% to 34% of mammography-detected cases.

The overall incidence of DCIS has increased greatly due to the widespread adoption of mammography as a screening technique. Due to the nature of DCIS, it is challenging to identify it without the use of screening methods as it rarely has obvious or palpable symptoms.

As DCIS is an early cancer, it often has few to no symptoms or signs. However, sometimes symptoms may present themselves such as:

• A breast lump
• Bloody nipple discharge

Since DCIS rarely shows symptoms, DCIS is normally first identified through a breast cancer screening where calcifications are observed on a mammogram by a doctor. The doctor may then recommend other tests, which could include a breast biopsy, to confirm the diagnosis. In most cases, a core-needle biopsy is done using a hollow needle to extract tissue samples from the breast. This procedure is usually guided using ultrasound (ultrasound-guided breast biopsy) or by X-ray (stereotactic breast biopsy). During a breast biopsy, breast tissue samples are taken, and a pathologist — a doctor specializing in analyzing body tissue and blood- examines the cells under a microscope to check for cancer.

As DCIS is non-invasive, the common treatment strategy would be to remove the tumor using surgery and reduce the chances of recurrence through radiation or hormone therapy (for tumors that are hormone-receptor positive). Chemotherapy is normally not recommended for DCIS. The surgical treatments usually recommended include:

• Lumpectomy (breast-preserving surgery)

A lumpectomy is a surgery that only removes the affected part of the breast together with a margin of healthy tissue that surrounds it.

• Mastectomy

A mastectomy is a surgery that removes the whole breast affected by DCIS.

The type of surgery recommended would depend on several factors, including:

• Size of the tumor relative to the size of the breast

If the tumor is large, relative to the size of breast, then a mastectomy is normally recommended.

• Number of affected areas on the breast

If there are multiple areas of DCIS on the breast, a mastectomy may be more effective in removing all the affected areas, primarily if they are found in different quadrants of the breast.

• Possibility of radiation therapy after surgery

Radiation therapy is normally done after lumpectomy to reduce the chances of recurrence. However, if the patient is unable to get radiation therapy or does not want to get radiation therapy, then a mastectomy may be recommended. A patient may not be able to get radiation therapy due to reasons such as pregnancy, prior radiation to the chest, or certain autoimmune conditions that make them sensitive to the side effects of radiation.

Radiation therapy uses high-energy rays to destroy cancer cells. It is normally used after a lumpectomy to get rid of any remaining cancer cells and reduce the chances of the cancer coming back in the same breast or nearby lymph nodes. It also reduces the chance of invasive breast cancer in either breast in the future.

For tumors that are hormone-receptor positive, hormone therapy can be considered to reduce the chances of recurrence.

Learn more: Using Medicine to Reduce Breast Cancer Risk

As DCIS is an early-stage cancer and is highly treatable, it has a very high survival rate. The 10-year survival rate for women diagnosed with DCIS is 98%.