The incidence of breast cancer in China is increasing year by year, and nearly 200,000 women are diagnosed with breast cancer each year. Standardizing the treatment standards and modalities for breast cancer is crucial to improve the prognosis of breast cancer patients. This article introduces the endocrine treatment for premenopausal and postmenopausal hormone receptor positive (HR+) breast cancer according to the Chinese expert consensus on endocrine treatment of breast cancer.
Premenopausal HR+ Early stage breast cancer
The incidence curve of breast cancer in China is bimodal, with the peak incidence at the age of 50 and 70, and the median age of incidence is 45 to 55, which suggests that premenopausal breast cancer patients account for more than 50% of the overall breast cancer patients in China.
1. Standard treatment regimen: Tamoxifen (TAM) for 5 to 10 years
2. TAM combined with ovarian function suppression (OFS)
(1) <35 years old, TAM +OFS is better than TAM alone
(2) ≥ 4 lymph node metastases
(3) 1 to 3 lymph node metastases, histological grade 3 and other multiple risk factors
(4) Poor multi-gene testing
The recommended duration of prognosis for OFS treatment is 5 years, and some low-risk patients can also be considered for 2-3 years of treatment.
Postmenopausal HR+ early stage breast cancer
The two major peaks of recurrence of HR+ breast cancer are 2-3 years and 7 years after surgery. Prolonged endocrine therapy can help reduce the risk of recurrence and increase the chance of cure for early stage patients.
1. Standard treatment: 5 years of TAM
2. TAM combined with aromatase inhibitor (AI) AI (anastrozole, letrozole or exemestane) can be the standard adjuvant therapy for postmenopausal HR+ breast cancer patients, but long-term AI can lead to adverse effects such as osteoporosis, joint pain and hot flashes, which affect patient tolerance.
For those who cannot tolerate AI, adjuvant TAM or sequential TAM and AI can be chosen.
3. Extended endocrine therapy for premenopausal and postmenopausal HR+ breast cancer patients
(1) Continue TAM therapy for 5 years (especially for high-risk patients) if they are not menopausal after 5 years of TAM.
(2) 5-year mid-menopause, switch to AI therapy for a total of 10 years.
(3) After menopause, 5 years of TAM; for those with grade 3 tumor, high Ki-67 value or lymph node metastasis, consider continuing TAM or AI therapy.
Extension of endocrine therapy
It should be treated on a case-by-case basis, considering not only the high-risk factors for tumor recurrence, but also the patient’s willingness and treatment compliance.
Advanced metastatic breast cancer (MBC)
Advanced breast cancer is incurable and the goal of treatment is to prolong survival and improve quality of life.
1. Indications for endocrine therapy
(1) ER+ patients with age > 35 years, DFS > 2 years after adjuvant therapy, bone and soft tissue metastases, and asymptomatic visceral metastases.
(2) ER- patients with slow tumor progression, which can be tried after the end of chemotherapy.
Patients who benefit from first-line endocrine therapy need to continue treatment. After failure, other endocrine therapy drugs can be changed, such as clear endocrine resistance can be combined with drugs that reverse resistance or switch to chemotherapy.
2. Metastasis after adjuvant therapy in advanced postmenopausal breast cancer
(1) Occurring after adjuvant TAM therapy: First-line endocrine therapy can be AI or fulvestrant 500 mg regimen.
(2) Occurring after adjuvant AI therapy: try fulvestrant 500 mg as the first choice (requires evidence-based therapy). For advanced breast cancer patients who have failed non-steroidal AI therapy, steroidal AI in combination with everolimus may be considered, but the benefits need to be weighed against the adverse effects of the drug.
Value of ovarian function protection in young breast cancer patients
Chinese women have a high rate of late marriage and late childbearing, and many young patients develop breast cancer before they have children. This group of patients has a need to preserve their reproductive function and should be treated along with breast cancer to protect ovarian function in this group of patients. (It is not yet widely available)
1. For HR- early stage patients with pregnancy intention, gonadotropin-releasing hormone booster (GnRHa) can be given at the same time as adjuvant chemotherapy to reduce the incidence of 2-year ovarian failure and increase the likelihood of subsequent pregnancy.
2, HR+ young patients, if they have a strong desire to have children during adjuvant endocrine therapy, they need to consider the degree of disease risk, disease-free interval, patient’s age, etc. Some of the medium to low-risk patients can be suspended after 2-3 years of endocrine therapy, try to get pregnant, and continue to receive complete endocrine therapy after pregnancy.