What is the recommended management for ductal carcinoma in situ (DCIS) smaller than one centimeter?

From the Guidelines

The recommended management for ductal carcinoma in situ (DCIS) smaller than one centimeter typically involves breast-conserving surgery (lumpectomy) followed by radiation therapy, as this approach has been shown to reduce the risk of local recurrence and is supported by the most recent and highest quality evidence 1.

Key Considerations

• The surgical procedure should aim to remove the abnormal tissue with clear margins, ideally 2mm or greater, as margin status is a significant predictor of local recurrence 1.
• Following surgery, whole breast radiation therapy is usually administered over 3-6 weeks to reduce the risk of local recurrence.
• For hormone receptor-positive DCIS, adjuvant endocrine therapy with tamoxifen (20mg daily for 5 years) or an aromatase inhibitor such as anastrozole (1mg daily for 5 years) in postmenopausal women may be recommended to further reduce recurrence risk 1.
• In select cases of low-risk DCIS (small size, low/intermediate grade, adequate surgical margins), omission of radiation therapy may be considered, particularly in elderly patients, as the risk of local recurrence following excision only may be low enough to omit radiation 1.

Additional Recommendations

• Regular follow-up with annual mammography is essential regardless of treatment approach to monitor for any signs of recurrence or new lesions.
• The use of a radiation boost to the tumor bed may be recommended in cases with higher risk features, such as larger areas of DCIS, margins <2 mm, or the presence of comedonecrosis, to maximize local control 1.
• Genetic counseling is recommended if the patient is considered to be at high risk for hereditary breast cancer, as defined by the NCCN Guidelines for Genetic/Familial High-Risk Assessment: Breast and Ovarian 1.

From the FDA Drug Label

The primary objective was to determine whether 5 years of tamoxifen therapy (20 mg/day) would reduce the incidence of invasive breast cancer in the ipsilateral (the same) or contralateral (the opposite) breast In this trial 1,804 women were randomized to receive either tamoxifen or placebo for 5 years: Over 80% of the tumors were less than or equal to 1 cm in their maximum dimension, were not palpable, and were detected by mammography alone. For the primary endpoint, the incidence of invasive breast cancer was reduced by 43% among women assigned to tamoxifen (44 cases-tamoxifen, 74 cases-placebo; p = 0.004; relative risk (RR) = 0.57,95% CI: 0.39 to 0. 84)

The recommended management for ductal carcinoma in situ (DCIS) smaller than one centimeter includes:

• Lumpectomy and radiation therapy
• Consideration of tamoxifen therapy for 5 years to reduce the incidence of invasive breast cancer, as it has been shown to reduce the incidence by 43% in women with DCIS 2 Key points:
• The majority of tumors in the study were less than or equal to 1 cm in size
• Tamoxifen therapy was associated with a significant reduction in the incidence of invasive breast cancer
• The decision to use tamoxifen should be based on individual patient factors and discussion with a healthcare provider 2

From the Research

Management of Ductal Carcinoma in Situ (DCIS) Smaller Than One Centimeter

The management of DCIS smaller than one centimeter involves several approaches, including:

• Surgical excision: This is the primary treatment for DCIS, with the goal of removing the tumor with clear margins 3, 4.
• Radiotherapy: This may be employed for local control in breast conservation, although it may be omitted for select low-risk situations 3, 5.
• Hormonal therapy: This may be used to reduce the risk of recurrence, particularly in patients with hormone receptor-positive DCIS 4, 5.

Risk Stratification

Risk stratification is important in determining the appropriate management for DCIS smaller than one centimeter. Factors such as tumor size, grade, and margin status are used to determine the risk of recurrence 4, 6.

• Low-risk DCIS: Patients with low-risk DCIS may be considered for omission of radiotherapy after lumpectomy, although this approach is still being studied 4, 5.
• High-risk DCIS: Patients with high-risk DCIS are generally recommended to receive radiotherapy after lumpectomy to reduce the risk of recurrence 4, 5.

Omission of Radiotherapy

The omission of radiotherapy after lumpectomy for DCIS smaller than one centimeter is still being studied. Some studies suggest that omission of radiotherapy may be safe for select low-risk patients, although this approach is not universally accepted 4, 5, 7.

• A study by NRG/RTOG 9804 found that radiotherapy significantly reduced the risk of ipsilateral breast recurrence in patients with good-risk DCIS, although the study did not specifically address tumors smaller than one centimeter 5.
• Another study found that even low-risk patients identified from multigene assays had higher rates of local recurrence with local excision alone than would be expected with the addition of radiotherapy 7.

Future Directions

Future research is focused on identifying low-risk patients who may not require radiotherapy after lumpectomy for DCIS smaller than one centimeter. Approaches such as multigene assays and biomarkers are being studied to determine their utility in risk stratification 4, 7.