The metastatic breast cancer (MBC) treatment plan your doctor will recommend depends on whether the tumors have receptors for estrogen or progesterone or elevated levels of human epidermal growth factor receptor 2 (HER2). These are known as a tumor’s biologic subtype.

There are various targeted therapies for each subtype of MBC.

People who are hormone receptor-positive and HER2-negative are usually given antiestrogen medications. Examples include an aromatase inhibitor, tamoxifen (Soltamox), or a drug called fulvestrant (Faslodex).

One exciting new class of medications for HER2-negative MBC is known as cyclin-dependent kinase 4/6 (CDK4/6) inhibitors. Examples include abemaciclib (Verzenio), palbociclib (Ibrance), and ribociclib (Kisqali).

When these medications are added to standard antiestrogen therapy, the length of time a person responds to therapy doubles as compared to antiestrogen therapy alone.

For MBC that is HER2-positive, there are a number of new targeted drugs that are effective and have few side effects. Examples include fam-trastuzumab deruxtecan-nxki (Enhertu) and tucatinib (Tukysa).

Treatment for hormone receptor-positive breast cancer can put women into early menopause. This can affect quality of life.

There are a variety of nonestrogenic lubricants that may help with vaginal dryness. Your doctor may also prescribe low-dose vaginal estrogen to treat vaginal dryness and painful intercourse.

Acupuncture has been shown to be helpful for hot flashes. In addition, there are several types of medications that can help.

MBC is a chronic illness and, in general, requires indefinite treatment. How long a treatment works depends on the biologic subtype of the cancer and the treatment itself.

Many people with hormone receptor-positive breast cancer are prescribed hormone therapy — such as an aromatase inhibitor or fulvestrant — in combination with a CDK4/6 inhibitor. This treatment keeps the breast cancer from growing for about 2 years on average. Some people do well on this therapy for much longer.

Your doctor may change to a different treatment regimen if your cancer progresses on your current treatment. Fortunately, there are many to choose from.

All MBC treatments can cause side effects. Doctors try their best to maximize the quantity and quality of life for people with MBC by monitoring side effects very carefully.

Your doctor will generally continue treatment for as long as you respond to it and tolerate it. Otherwise, your doctor may change therapies or adjust your dose.

Alternative therapies may help. Recent research indicates that acupuncture may ease common side effects including hot flashes, joint pain, and neuropathy (numbness and tingling of the fingers and toes).

Don’t hesitate to communicate with your doctor about how you’re feeling. This will help your care team better understand and address any symptoms you’re experiencing.

Exercise has been shown to minimize some side effects from cancer and cancer therapies, including fatigue, nausea, depression, and anxiety.

A cancer diagnosis can be stressful. It’s important to ask for psychosocial support. Most cancer centers have dedicated social workers, psychologists, and psychiatrists. You might also find cancer support groups beneficial.

Lack of energy and exhaustion are common for people with MBC. Exercise is the best treatment for fatigue related to cancer and cancer treatments. Eating well, staying hydrated, and getting plenty of sleep may also help.

Cancer treatments can be very expensive, even if you have health insurance. Some newer medications available today have very high copays.

Fortunately, many pharmaceutical companies have patient financial assistance programs to help with this. Social workers can help patients access these programs. Ask your doctor and hospital social services for help.

People are living longer and longer with MBC. The future of MBC treatment is very bright.

New and effective biologic and targeted therapies are approved every year to help improve quantity and quality of life, and a huge number of ongoing trials continue to uncover new medications that help treat MBC.

Amy Tiersten, MD, is a professor of medicine and Clinical Director of Breast Medical Oncology at Mount Sinai Hospital in New York City.