From the Guidelines
Focal ductal carcinoma should be treated with surgical removal of the tumor, followed by radiation therapy, and adjuvant endocrine therapy to reduce the risk of recurrence, as recommended by the most recent guidelines 1. The goal of primary therapy for ductal carcinoma in situ (DCIS) is to prevent progression to invasive breast carcinoma. Management strategies for DCIS treatment include surgery (mastectomy or lumpectomy), radiation therapy (RT), and adjuvant endocrine therapy to reduce risk of recurrence.
- Surgical excision is the mainstay of therapy, with most women being candidates for breast-conserving surgery, whereas some may require mastectomy based on the extent of DCIS in the breast 1.
- Radiation therapy after breast-conserving surgery reduces the recurrence risk of DCIS or invasive breast cancer in the ipsilateral breast, with moderately hypofractionated treatment schedules being as effective as standard fractionation treatment schedules in management of DCIS 1.
- The addition of boost lowers recurrence rates in non-low-risk DCIS cases, and is recommended in cases with larger areas of DCIS or other factors associated with increased risk of recurrence, including margins <2 mm and the presence of comedonecrosis 1.
- Adjuvant endocrine therapy can further reduce the risk of recurrence in DCIS treated with breast conservation and radiation therapy, as well as prevent contralateral disease, with either tamoxifen or an aromatase inhibitor being options 1. The prognosis for focal ductal carcinoma is generally favorable when detected early, with 5-year survival rates exceeding 90% for localized disease, and the specific treatment approach is individualized based on the patient's age, overall health, tumor characteristics, and personal preferences after discussion with their healthcare team 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: 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). Table 1: Major Outcomes of the NSABP B-24 Trial
- Invasive breast cancer (Primary endpoint)74 16.7 34 9.6 0.57 0.39 to 0.84
The use of tamoxifen for 5 years reduces the incidence of invasive breast cancer by 43% in women with ductal carcinoma in situ (DCIS), as shown in the NSABP B-24 trial 2.
- The relative risk (RR) of invasive breast cancer was 0.57 (95% CI: 0.39 to 0.84) for the tamoxifen group compared to the placebo group.
- The reduction in invasive breast cancer incidence was statistically significant (p = 0.004).
From the Research
Focal Ductal Carcinoma
- Focal ductal carcinoma, also known as ductal carcinoma in situ (DCIS), is a non-invasive cancer where cells are contained in the milk ducts of the breast 3.
- The management of DCIS typically involves breast conservation surgery, radiation therapy, and hormonal therapy to reduce the risk of recurrence 3, 4.
- Studies have shown that the addition of radiation therapy after breast conservation surgery can reduce the rate of ipsilateral local recurrence by about half, and the addition of hormonal therapy can reduce the rate of all breast cancer events 3.
Risk Factors and Recurrence
- Risk factors for recurrence after mastectomy for DCIS are not well established, but may include close or positive mastectomy margins, age at diagnosis, extent of breast disease, and mutation carriers 5.
- Local recurrence rates after mastectomy for DCIS are reportedly low, with one study finding a 10-year relapse-free survival rate of 97% 6.
- Another study found that recurrence after mastectomy for pure DCIS is a rare event, with only one recurrence occurring in a cohort of 165 patients 5.
Treatment Options
- Treatment options for DCIS include breast conservation surgery, mastectomy, radiation therapy, and hormonal therapy 3, 4.
- Active surveillance is also being explored as a potential treatment option for DCIS, particularly for low-risk patients 7.
- Multigene expression assays may be useful in stratifying patients at increased risk for progression to invasive breast cancer, and could potentially guide treatment decisions 7.