Ductal Carcinoma In Situ (DCIS) is an early form of breast cancer. It is considered a non-invasive, Stage 0 condition, meaning the abnormal cells are contained entirely within the milk ducts. While the term “carcinoma” can cause concern, a diagnosis of DCIS, even high-grade, generally carries a favorable outlook.
Understanding High-Grade DCIS
The term “high-grade” or “Grade 3” in DCIS refers to how abnormal the cancer cells appear when examined under a microscope. Pathologists classify DCIS into three grades based on cellular characteristics: Grade 1 (low-grade), Grade 2 (intermediate-grade), and Grade 3 (high-grade). High-grade DCIS cells look distinctly different from normal breast cells and tend to grow more rapidly compared to lower-grade cells.
High-grade DCIS is frequently associated with comedonecrosis. This term describes areas of dead cancer cells within the milk duct, occurring when rapidly growing cells outgrow their blood supply. The presence of comedonecrosis often suggests a more aggressive form of DCIS and guides treatment and follow-up care.
Survival Rates and Recurrence Risks
The long-term survival rate for individuals diagnosed with DCIS is very high, approaching 100%. While the risk of death from DCIS is exceedingly low, the primary concern revolves around the potential for recurrence within the breast.
Recurrence can manifest in two ways: as a return of DCIS in the same breast (local recurrence) or as the development of new invasive breast cancer. For high-grade DCIS, the risk of recurrence is influenced by the specific treatments received. The overall recurrence rate for DCIS is estimated at around 15% for individuals who undergo both surgery and radiation therapy. About half of these recurrences are found to be invasive breast cancer. Studies indicate that the 10-year cumulative incidence of ipsilateral (same breast) invasive breast cancer after DCIS treatment is approximately 3.2%.
Treatment Approaches and Their Impact
Treatment for high-grade DCIS primarily aims to eliminate abnormal cells and reduce the likelihood of recurrence or progression to invasive cancer. Surgery is the most common initial step, with two main options: lumpectomy or mastectomy. A lumpectomy, also known as breast-conserving surgery, removes the DCIS and a small margin of healthy tissue, preserving most of the breast. A mastectomy involves removing the entire breast and may be recommended if the DCIS is widespread, involves multiple areas, or cannot be fully removed with a lumpectomy.
Following a lumpectomy for high-grade DCIS, radiation therapy is often recommended to destroy any remaining abnormal cells and further reduce the risk of local recurrence. If a mastectomy is performed, radiation therapy is typically not needed, as the entire breast tissue containing the DCIS is removed.
Hormone therapy may be considered for high-grade DCIS if the cells are found to be hormone receptor-positive (ER/PR-positive). These therapies, such as tamoxifen or aromatase inhibitors, work by blocking the effects of hormones like estrogen that can fuel cancer cell growth. Taking hormone therapy after surgery, especially after a lumpectomy, can help lower the risk of DCIS recurrence and the development of future invasive breast cancer. Chemotherapy is generally not utilized for DCIS, as it is a non-invasive condition. Lymph nodes are usually not removed unless the DCIS is extensive or there is a suspicion of invasive cancer.
Factors Influencing Prognosis
Beyond the grade of DCIS, several specific factors from a pathology report provide additional information that guides personalized prognosis and treatment planning. One such factor is surgical margins, which refers to the rim of healthy tissue surrounding the removed DCIS. Achieving “clear” or “negative” margins, typically defined as at least 2 millimeters of healthy tissue, indicates that no cancer cells are present at the edge of the removed specimen and is associated with a lower risk of recurrence. If margins are “positive” (cancer cells are touching the edge), additional surgery may be necessary to ensure all abnormal cells are removed.
The size and extent of the DCIS area also influence treatment decisions and prognosis. Larger areas of DCIS can increase the likelihood of recurrence. For instance, a large DCIS (50 millimeters or more) has been associated with a higher risk of developing more advanced stages of invasive breast cancer if it recurs.
Hormone receptor status is another detail. This indicates whether the DCIS cells have receptors for hormones like estrogen (ER-positive) or progesterone (PR-positive), suggesting these hormones may contribute to cell growth. Individuals with ER-positive and PR-positive DCIS, who receive tamoxifen therapy, have shown a better survival outcome. This information helps determine if hormone therapy is a suitable addition to the treatment plan, as it can reduce the risk of future breast cancer development.