Ductal Carcinoma In Situ (DCIS) is the earliest form of breast cancer. It is considered a non-invasive, or stage 0, cancer because the abnormal cells are contained within the milk ducts of the breast. A mastectomy, the surgical removal of the entire breast, is one treatment option for DCIS. This approach is often chosen to reduce the possibility of the cancer returning, and understanding the likelihood of recurrence is a common concern.
Overall Risk of Recurrence After Mastectomy
The likelihood of DCIS returning after a mastectomy is very low. Because a mastectomy removes nearly all of the breast tissue where DCIS originates, the chance for the cancer to come back in the same area is minimal. The overall risk for a local recurrence is about 1-2% over a 10-year period following the surgery.
This small percentage reflects cases where cancer cells reappear on the chest wall, which includes the skin or muscle where the breast used to be. The effectiveness of the surgery lies in its thoroughness, as the removal of the ductal systems that house the DCIS cells leaves very little tissue behind for a new cancer to develop.
For most individuals, a mastectomy is considered a curative treatment for DCIS. The small chance of recurrence is why many patients, in consultation with their doctors, opt for this procedure, particularly when the DCIS is widespread throughout the breast.
Factors That Can Affect Recurrence Risk
While the general risk of DCIS recurrence after a mastectomy is low, specific characteristics of the original tumor can influence an individual’s chances. One of the main factors is the tumor’s grade, which describes how abnormal the cancer cells appear under a microscope. High-grade DCIS cells look more irregular and grow faster, and they are associated with a slightly higher tendency to recur.
Another factor is the presence of comedonecrosis within the tumor. This term refers to areas of dead, or necrotic, cancer cells that have built up inside the duct. Comedonecrosis is often found in high-grade DCIS and is considered a sign of a more aggressive form of the non-invasive cancer.
The size and extent of the DCIS can also play a role. Very large areas of DCIS or disease that is multifocal, meaning it appears in several different locations within the breast, may increase the chance of recurrence. Younger age at diagnosis, particularly for patients under 40, has also been identified as a factor associated with a greater risk of recurrence.
Types of Potential Recurrence
When a recurrence does happen after a mastectomy for DCIS, it can present in different ways. The term “recurrence” simply means the cancer has returned, but the nature of that new cancer is a separate consideration. Understanding these distinctions is part of comprehending the full picture of risk.
Roughly half of the time, if a local recurrence occurs, it will be another instance of non-invasive DCIS. The other half of recurrences are invasive ductal carcinoma (IDC). In an invasive recurrence, the cancer cells have broken out of the ducts and have the potential to spread to other parts of the body.
Recurrence is also classified by its location. A local recurrence is one that appears on the chest wall at the site of the original mastectomy. A regional recurrence is one that develops in the nearby lymph nodes, such as those in the armpit. Regional recurrences after a mastectomy for DCIS are very uncommon.
Post-Mastectomy Monitoring and Follow-Up
Following a mastectomy for DCIS, a regular monitoring plan is put in place to watch for any signs of recurrence. The core of this plan involves routine physical examinations with a doctor. During these appointments, the surgeon or oncologist will carefully check the chest wall, the mastectomy scar, and the surrounding areas, including the armpit.
Patients are also educated on how to perform a monthly self-exam of the surgical site. This involves looking for and feeling for any new or unusual lumps, bumps, areas of thickness, or skin changes like redness or dimpling. Being familiar with the normal post-surgical contours of the chest wall helps in quickly identifying any new developments.
If the mastectomy was performed on only one breast, continued surveillance of the remaining breast is a standard part of the follow-up plan. This typically includes an annual mammogram on the intact breast. This imaging allows for the early detection of any new issues in that breast, which is separate from the risk of recurrence at the mastectomy site.