- Treatment is dictated by 3 main factors: breast cancer tumor subtype (hormone receptor [HR]-positive, HER2-positive, and triple-negative breast cancer [TNBC]), anatomic cancer stage, and patient preference.
- Treatment has changed dramatically for metastatic cancer in the last 6 years with the introduction of 6 medications in the United States: 3 CDK4/6 inhibitors, 2 PARP inhibitors, and an HER2-targeted antibody conjugate.
Why this matters
- Breast cancer affects 12% of women over their lifetime; in 2017, 250,000 new cases were diagnosed in the United States.
- Early-stage breast cancer has 85%-99% 5-year cancer-specific survival depending on tumor subtype; metastatic breast cancer has 4-5-year median OS for HR+ and HER2+ and 10-13 months for TNBC subtypes.
- Treatment goals for nonmetastatic disease, using local (surgery and radiotherapy) and systemic therapy, are to achieve tumor eradication and prevention of recurrence; for metastatic disease, they are to prolong life and palliate symptoms.
- Detailed tables summarize:
- therapeutic options by subtype for nonmetastatic disease and metastatic disease (including initial lines and later lines) plus overall response rates,
- important toxicities by regimen,
- treatment and long-term outcomes by genomic risk scores in nonmetastatic breast cancer, and
- new drug approvals for metastatic breast cancer by drug class, mechanism-of-action, indications, notable toxicities.