I. Update points
There are few updates in this guideline on the management of advanced breast cancer, mainly including.
1. For patients with metastatic breast cancer, the metastatic site should be biopsied again to determine ER/PR and HER-2 status. If biopsy samples cannot be safely obtained, treatment should be based on the ER/PR and HER-2 test results of the primary tumor.
The optimal regimen for zoledronic acid is once a month, reduced to once every 3 months after 12 months.
3. Limited studies have shown a benefit in progression-free survival (PFS) with the addition of trastuzumab or lapatinib in postmenopausal patients who are ER and HER-2 positive and on aromatase inhibitors, but no evidence of prolonged overall survival (OS).
4. Patients with metastatic breast cancer already treated with chemotherapy and trastuzumab may be considered for a regimen of trastuzumab in combination with patuximab therapy with or without cytotoxic agents (e.g., vincristine, paclitaxel).
II. Treatment of local/regional recurrence
1. Patients with local recurrence of breast cancer will undergo surgical re-excision if possible. If not initially treated with radiation therapy, irradiation of chest wall, supraclavicular lymph nodes and subclavian lymph nodes will be performed postoperatively. If necessary, systemic treatment should be given first to achieve the best remission rate before surgical resection.
2. For patients with local recurrence who have undergone primary local lesion excision, total mastectomy + axillary lymph node dissection is performed.
3.Patients with regional recurrence should all undergo radiation therapy to the chest wall, supraclavicular lymph nodes, subclavicular lymph nodes and the corresponding regional lymph nodes.
4. Systemic treatment should be continued after local treatment
Treatment of bone metastasis
Bone metastasis is the most common distant metastasis of breast cancer, with an incidence of 49%-60%. Bone metastasis itself does not pose a direct threat to life, but the bone-related events caused by it can lead to extreme pain and seriously affect patients’ quality of life. Therefore, the treatment of bone metastases is of great importance.
For patients with breast cancer bone metastases with expected survival ≥ 3 months and creatinine < 3.0 mg/dl, denosumab, zoledronic acid or pamidronate disodium should be added to the regimen of conventional chemotherapy and endocrine therapy against bone destruction, especially for patients with osteolytic bone metastases and/or weight-bearing bone metastases (Class I recommendation).
2. For osteolytic bone metastases, zoledronic acid is preferred over pamidophosphate.
3. Studies have shown that the use of bisphosphonates and denosumab has the potential to cause osteonecrosis of the jaw (incidence approximately 5.48%), with poor underlying oral health status or dental surgery during drug administration being known risk factors. Therefore, it is recommended that patients undergo dental examination and prophylaxis before receiving intravenous administration of these drugs, and avoid dental procedures during treatment if possible.
4. No studies have shown an effect of bisphosphonate or denosumab use on overall survival.
5. Calcium and vitamin D should be supplemented with a daily dose of 1200-1500 mg of calcium and 400-800 IU of vitamin D3 while taking bisphosphonates.
6. Current research data support a 2-year duration of treatment with bisphosphonates.
Endocrine therapy
Patients with ER and/or PR positive advanced breast cancer are suitable for endocrine therapy, mainly including Nonsteroidal Aromatase Inhibitors (Anastrozole and Letrozole), Steroidal Aromatase Inhibitors (Exemestane), Selective Estrogen Receptor Modulators (SERMs; Tamoxifen, Toremifene), Selective Estrogen Receptor Downregulators ( Selective Estrogen Receptor Down-odulators (SERDs; fulvestrant); for most patients with advanced premenopausal breast cancer treated with tamoxifen, ovarian debulking or resection with endocrine therapy regimens are also appropriate options.
For premenopausal patients with ER and/or PR positive who have received endocrine therapy within the last 1 year, ovarian debulking or resection with postmenopausal endocrine therapy is recommended; premenopausal patients who have not received endocrine therapy within 1 year can also be treated with SERMs (tamoxifen, toremifene).
2. Postmenopausal patients with ER and/or PR positivity who have received endocrine therapy within the last 1 year can continue the original regimen until disease progression; postmenopausal patients who have not received endocrine therapy within 1 year are recommended to be treated with Aromatase Inhibitors-AIs (anastrozole, letrozole or exemestane) or SERMs (tamoxifen, toremifene) or SERDs (fulvestrant).
3. Because of the possibility of false-negative ER/PR tests, endocrine therapy may be considered in patients with metastatic breast cancer with non-visceral metastases or asymptomatic visceral metastases even if they are hormone receptor negative, especially in patients with clinical features suggesting the possibility of hormone receptor positivity (e.g., long disease-free survival, limited recurrent foci, slowly progressing lesions, advanced age, etc.).
4. A phase III clinical trial demonstrated a benefit in progression-free survival (PFS) with 500 mg fulvestrant versus a 250 mg dose (HR 0.8), with the final analysis showing a 4.1 month increase in median overall survival (OS) (26.4 : 22.3) and a 19% reduction in the risk of death (HR 0.81).
For postmenopausal patients with recurrent breast cancer who have been treated with anti-estrogen drugs for less than 1 year, there is evidence to support the use of AI as a first-line treatment option.
6. One of the mechanisms of resistance to endocrine therapy in breast cancer is the activation of the Mammalian Target Of Rapamycin-mTOR signaling pathway. An intention-to-treat analysis showed a greater advantage of tamoxifen in combination with everolimus than tamoxifen alone in the treatment of patients with endocrine drug resistance (PFS 8.5m: 4.5m).
However, in the other BOLERO-2 trial, there was no difference in the results of letrozole in combination with everolimus versus letrozole alone. The reason for the inconsistent results of the two trials is unknown and may be related to the degree of prior endocrine therapy and the type of drug the patient received.
The BOLERO-2 trial showed that exemestane combined with everolimus significantly prolonged PFS in postmenopausal hormone receptor-positive breast cancer patients with recurrence or progression after treatment with nonsteroidal aromatase inhibitors, and the panel strongly recommended that patients who met the BOLERO-2 enrollment criteria be treated with the above regimen.
V. Chemotherapy and Targeted Therapy
The guidelines recommend that patients with advanced breast cancer who are hormone receptor negative, whose metastases are not confined to bone or soft tissue and have significant symptoms, or who are hormone receptor positive but have failed endocrine therapy may receive chemotherapy.
1. In single-agent regimens, eribulin is indicated for patients with metastatic breast cancer who have received at least two chemotherapy regimens containing anthracyclines and paclitaxel. Eribulin has a greater advantage in OS and PFS than the rest of single-agent regimens.
2. The first-line regimen for patients with HER2-positive advanced breast cancer is either pertuzumab + trastuzumab + docetaxel (Class I recommendation) or pertuzumab + trastuzumab + paclitaxel.
3. T-DM1 therapy is recommended for patients with advanced disease who have been previously treated with trastuzumab.
VI. Summary
There are many treatment options for advanced breast cancer, and despite the extensive clinical use as a basis, there is still no single option that achieves maximum efficacy and minimum toxicity, so patients should not be satisfied with just accepting the current level of treatment. It is the responsibility of both the patient and the clinician to explore the most appropriate treatment options.