1. How should breast brain metastasis be treated?
Treatment for breast cancer brain metastasis includes surgery, whole brain radiation therapy (WBRT) or stereotactic radiotherapy (SRT), chemotherapy and biotherapy.
2. What are the main conservative treatments for breast cancer brain metastasis?
The main conservative treatments for breast cancer brain metastasis are: (1) To reduce tumor edema, mannitol and dexamethasone (8~32mg/d)/methylprednisolone can be used, but long-term use of steroid hormone has side effects such as osteoporosis, weight gain, bleeding tendency and abnormal blood sugar. (2) Seizure control can be achieved by considering antiepileptic drug treatment for those who have seizures, but attention should be paid to rash, vertigo, drowsiness and the rare but more serious Stevens-Johnson syndrome.
3. Is surgical treatment of brain metastases from breast cancer meaningful? Which sites of brain metastases from lung cancer are suitable for surgical treatment?
Surgery plays an important role in the treatment of breast cancer brain metastases. Surgery can reduce the occupying effect, improve neurological function and enhance the quality of life by removing metastatic tumor foci, which is also the key to determine the length of patients’ survival.
It is important to note that 6% of MRI-enhanced lesions in the brain of cancer patients are primary tumors in the brain and 5% may be inflammatory lesions. Breast cancer patients often have a tendency to have a high incidence of meningioma, therefore, for certain lesions of unknown pathological nature, surgical excision of the lesion to clarify the pathological diagnosis is crucial for subsequent treatment.
For single brain metastases from breast cancer, surgical resection is the first treatment option. For multiple metastases, surgical total resection can achieve similar survival as that of single metastases.
About 5%-15% of breast cancer brain metastases will continue to grow after whole brain radiotherapy and stereotactic radiosurgery, and can still be treated aggressively if they are suitable for surgical resection.
4. Is whole brain radiotherapy needed for breast cancer brain metastasis? What are the adverse effects after radiotherapy?
Whole brain radiotherapy (WBRT) is suitable for patients with multiple intracranial metastases, tumor diameter <3cm, not suitable for surgery or stereotactic radiosurgery, and patients with moderate intracranial pressure increase. Whole-brain radiotherapy after microsurgical resection of metastatic tumors can significantly reduce the possibility of local tumor recurrence in the tumor cavity.
The commonly used whole-brain radiotherapy regimen is a 30 Gy/10-times regimen (3 Gy per day, 5 days per week for 2 weeks). A 40 Gy/20 fractionated radiotherapy regimen (2 Gy per day, 5 days per week for 4 weeks) is recommended for breast cancer patients with potential long-term survival.
Acute adverse reactions occur mostly within 90 days after radiotherapy and include nausea, vomiting, hair loss, deafness, acute subacute skin reactions of the throat, and drowsiness, most of which disappear at the end of treatment.
Late adverse reactions occur after 90 days of radiotherapy and include radionecrosis, personality and memory changes, and cognitive deficits. Brain damage due to radiotherapy can appear 1 to 2 years after radiotherapy and progresses slowly. Early symptoms are recent memory loss (dementia in severe cases), ataxia, disorientation, drowsiness and diphtheria, and brain failure in severe cases.
5. Which patients with breast cancer brain metastases are suitable for stereotactic radiosurgery (Gamma Knife) treatment?
Stereotactic radiosurgery (SRS) treatment usually does not make the tumor disappear, but aims to control the tumor growth. It is mainly suitable for metastases within 3cm3, without bleeding, without cystic changes, without significant occupying effect and without serious neurological dysfunction, especially for metastases located in the basal ganglia, thalamus, brainstem and other deep areas where surgical treatment is difficult.
The single dose of stereotactic radiosurgery is usually 15-25Gy, and a marginal dose of at least 18Gy is required to obtain an acceptable local control rate without combined whole brain radiotherapy.
Do patients with breast cancer brain metastases need to receive stereotactic radiosurgery combined with whole brain radiotherapy?
Stereotactic radiosurgery combined with whole brain radiotherapy can improve local control rate and reduce the risk of local recurrence, but it has no significant effect on improving survival rate and increases the risk of radiotherapy complications, so microsurgical excision of the lesion + stereotactic radiosurgery is more recommended.
Complications of stereotactic radiosurgery combined with whole brain radiotherapy include: acute complications such as nausea (2%-10%) and epilepsy (2%-6%); subacute complications of complete alopecia (about 5%); chronic complications of transient new or worsening neurological dysfunction (5%-15%), permanent neurological dysfunction (1%-5%) and radionecrosis (1%-6%).
7. Is there a role for chemotherapy in patients with brain metastases from breast cancer?
The use of chemotherapy in the treatment of patients with brain metastases from breast cancer has been controversial. Chemotherapy alone is generally used for patients with multiple brain metastases who cannot receive surgical treatment.
Combination of radiotherapy and chemotherapy is usually started one week before radiotherapy, with one additional chemotherapy session after 20Gy of radiotherapy, followed by 4~6 courses of chemotherapy thereafter.
8. Is molecular targeted therapy suitable for patients with brain metastases from breast cancer?
Although trastuzumab can significantly reduce the risk of recurrence in Her2 overexpressed early-stage breast cancer, it cannot cross the blood-brain barrier and has limited value in the treatment of brain metastasis from breast cancer.
Lapatinib, a small molecule targeting Her1 and Her2, can cross the blood-brain barrier, but its efficacy in patients with brain metastases from breast cancer has yet to be proven.
9. Is there a role for endocrine therapy in patients with brain metastases from breast cancer?
Endocrine therapy is not currently recommended as first-line treatment for brain metastases from breast cancer. Endocrine therapy can be tried for patients with receptor-positive breast cancer brain metastases with mild symptoms. However, although tamoxifen can cross the blood-brain barrier, most patients with brain metastases from breast cancer are advanced and have developed resistance to tamoxifen in previous treatment, so the therapeutic effect is quite limited.