What is the recommended next treatment for a 64-year-old woman with Stage 1 breast cancer, estrogen (ER) and progesterone (PR) receptor-positive, human epidermal growth factor receptor 2 (HER2) negative, status post (s/p) mastectomy with negative lymph nodes, at a one-month follow-up visit?

From the Guidelines

For a 64-year-old woman with Stage 1, ER/PR-positive, HER2-negative breast cancer who has undergone mastectomy with negative lymph nodes, the recommended next treatment at one-month follow-up is adjuvant endocrine therapy with an aromatase inhibitor such as anastrozole (1 mg daily), letrozole (2.5 mg daily), or exemestane (25 mg daily) for 5-10 years, as supported by the most recent guidelines 1. Given her postmenopausal status at 64 years old, aromatase inhibitors are preferred over tamoxifen as they provide superior disease-free survival in postmenopausal women.

Key Considerations

• Treatment should begin as soon as surgical healing is adequate, typically within 4-12 weeks after surgery.
• Regular follow-up visits every 3-6 months for the first few years are important to monitor for side effects such as bone loss, joint pain, and cardiovascular issues.
• Bone density testing should be performed at baseline and periodically during treatment, with calcium and vitamin D supplementation recommended.
• This endocrine therapy is crucial because it blocks estrogen production or action, preventing stimulation of any remaining microscopic cancer cells that might be present despite the negative lymph nodes, thereby reducing recurrence risk by approximately 50%.
• No chemotherapy is typically indicated for this early-stage, node-negative disease with favorable biology, particularly in an older patient, as per the guidelines from the St Gallen International Consensus Conference for the primary therapy of individuals with early breast cancer 2023 1.

Additional Recommendations

• The patient should be encouraged to consider regular exercise and nutritional counseling to improve prognosis and overall health, as suggested by previous guidelines 1.
• Regular monitoring for potential side effects of endocrine therapy, such as changes in lipid profiles, is also recommended 1.

From the FDA Drug Label

The NSABP B-14, a prospective, double-blind, randomized study, compared tamoxifen to placebo in women with axillary node-negative, estrogen-receptor positive (≥ 10 fmol/mg cytosol protein) breast cancer (as adjuvant therapy, following total mastectomy and axillary dissection, or segmental resection, axillary dissection, and breast radiation) After five years of treatment, there was a significant improvement in disease-free survival in women receiving tamoxifen. In the EBCTCG 1995 overview, the reduction in recurrence and mortality was greater in those studies that used tamoxifen for about 5 years than in those that used tamoxifen for a shorter period of therapy.

The recommended next treatment for a 64-year-old woman with Stage 1 breast cancer, estrogen (ER) and progesterone (PR) receptor-positive, human epidermal growth factor receptor 2 (HER2) negative, status post (s/p) mastectomy with negative lymph nodes, at a one-month follow-up visit is:

• Hormonal therapy: Tamoxifen 20 mg daily for about 5 years, as it has been shown to improve disease-free survival in women with axillary node-negative, estrogen-receptor positive breast cancer 2.
• The benefits of tamoxifen appear to be independent of estrogen receptor status, and the reduction in recurrence and mortality is greater with 5 years of treatment compared to shorter durations.
• Key points:
  • Tamoxifen improves disease-free survival
  • 5 years of treatment is more effective than shorter durations
  • Benefits are independent of estrogen receptor status

From the Research

Next Treatment Recommendations

For a 64-year-old woman with Stage 1 breast cancer, estrogen (ER) and progesterone (PR) receptor-positive, human epidermal growth factor receptor 2 (HER2) negative, status post (s/p) mastectomy with negative lymph nodes, at a one-month follow-up visit, the recommended next treatment is adjuvant endocrine therapy.

• The patient's hormone receptor-positive status makes her a candidate for endocrine therapy, which has been shown to reduce the risk of recurrence and improve survival outcomes 3, 4, 5.
• Given the patient's postmenopausal status, aromatase inhibitors (AIs) such as anastrozole, letrozole, or exemestane are recommended as adjuvant therapy 6, 3, 4.
• The choice of AI and duration of therapy should be individualized based on the patient's menopausal status, tumor characteristics, and other factors 3, 5.
• The patient should be monitored for changes in bone mineral density and cardiovascular disease risk factors and outcomes while on AI therapy 3.
• Genomic assays and other biomarkers may also be considered to help guide treatment decisions and individualize therapeutic decision-making 5.

Adjuvant Endocrine Therapy Options

The following options are available for adjuvant endocrine therapy:

• Anastrozole or letrozole for five years 3
• Anastrozole or exemestane following two to three years of tamoxifen, for a total of five years of hormonal therapy 3
• Five years of letrozole after five years of tamoxifen 3

Management of Side Effects

AIs can cause side effects such as vasomotor symptoms, vaginal dryness, dyspareunia, bone loss, arthralgias, and myalgias, which can be managed with various interventions to improve adherence and persistence with therapy 6.