What is the recommended treatment for a patient with hormone receptor-positive DCIS?

From the Guidelines

The recommended treatment for hormone receptor-positive ductal carcinoma in situ (DCIS) is surgical removal of the tumor followed by radiation therapy and endocrine therapy, with tamoxifen or an aromatase inhibitor such as anastrozole being considered for 5 years to reduce recurrence risk. Surgery options include breast-conserving surgery (lumpectomy) or mastectomy, depending on factors like tumor size, location, and patient preference. After lumpectomy, radiation therapy is usually recommended to reduce recurrence risk. For hormone receptor-positive DCIS, endocrine therapy with tamoxifen (20mg daily for 5 years) or an aromatase inhibitor like anastrozole (1mg daily for 5 years) for postmenopausal women is often prescribed to further reduce recurrence risk, as shown in studies such as the NSABP B-24 trial 1 and the IBIS-II trial 1. Tamoxifen works by blocking estrogen receptors, while aromatase inhibitors prevent estrogen production. The choice between these treatments depends on menopausal status, comorbidities, and potential side effects, with guidelines such as those from the NCCN 1 providing recommendations for management. Regular follow-up with clinical exams and mammography is essential. This multimodal approach is effective because DCIS is a non-invasive breast cancer where malignant cells are confined to the milk ducts, and hormone receptor positivity indicates that the cancer cells grow in response to hormones like estrogen. Key considerations include:

• The patient's menopausal status, as this influences the choice between tamoxifen and an aromatase inhibitor
• The presence of comorbidities, which may affect the tolerability of certain treatments
• Potential side effects of endocrine therapy, which must be weighed against the benefits of reduced recurrence risk
• The importance of regular follow-up to monitor for recurrence and address any concerns or side effects promptly.

From the FDA Drug Label

Tamoxifen citrate tablets are used: to lower the chance of getting breast cancer in women with a higher than normal chance of getting breast cancer in the next 5 years (high-risk women) to lower the chance of getting invasive (spreading) breast cancer in women who had surgery and radiation for ductal carcinoma in situ (DCIS). Tamoxifen citrate tablets may block the growth of breast cancers that need estrogen to grow (cancers that are estrogen- or progesterone-receptor positive)

The recommended treatment for a patient with hormone receptor-positive DCIS is tamoxifen citrate tablets to lower the chance of getting invasive breast cancer.

• The studies showed that on average, women with DCIS who took tamoxifen citrate tablets lowered their chances of getting invasive breast cancer by 43%, from 17 in 1,000 to 10 in 1,000 2.

From the Research

Treatment Options for Hormone Receptor-Positive DCIS

• The recommended treatment for a patient with hormone receptor-positive DCIS includes adjuvant tamoxifen, which has been shown to reduce recurrence rates by almost 50% 3.
• Aromatase inhibitors are also likely to be effective in DCIS, with studies suggesting significant effects on DCIS, including reduced PgR expression and proliferation 3.
• The NSABP B-24 study demonstrated a significant benefit with adjuvant tamoxifen in patients with DCIS after lumpectomy and radiation, with a 27% reduction in the annual incidence rate of all breast cancer-related events 4.
• A retrospective evaluation of the NSABP B-24 study found that patients with ER-positive DCIS treated with tamoxifen showed significant decreases in subsequent breast cancer at 10 years and overall follow-up 5.

Benefits and Risks of Tamoxifen and Aromatase Inhibitors

• Tamoxifen has been shown to reduce the risk of breast cancer recurrence in women with ER-positive DCIS, but may also increase the risk of adverse events such as endometrial cancer, thromboembolic events, and cataracts 4, 5.
• Aromatase inhibitors may be more effective than tamoxifen in reducing the risk of breast cancer recurrence, but may also increase the risk of bone fractures and other adverse events 6.
• The choice of treatment should be individualized based on the patient's specific needs and risk factors, with consideration of the potential benefits and risks of each treatment option.

Current Research and Recommendations

• Recent studies have confirmed the effectiveness of tamoxifen and aromatase inhibitors in reducing the risk of breast cancer recurrence in women with ER-positive DCIS 7, 6.
• The use of adjuvant tamoxifen or aromatase inhibitors should be considered for patients with ER-positive DCIS, particularly those with a high risk of recurrence 7, 5.
• Further research is needed to fully understand the benefits and risks of each treatment option and to determine the optimal treatment strategy for individual patients.