Chapter 89: Breast Cancer

Content Update

July 03, 2024

Capivasertib Approved in Combination with Fulvestrant for Hormone Receptor Positive Metastatic Breast Cancer with One or More PIK3CA/AKT1/PTEN Alterations: The tyrosine kinase inhibitor capivasertib is approved in combination with fulvestrant for patients with hormone receptor positive (HR+), human epidermal growth factor negative (HER2-), PIK3CA/AKT1/PTEN, mutated metastatic breast cancer following progression on at least one endocrine therapy. Combination capivasertib-fulvestrant was evaluated in CAPItello-291, a phase III, randomized, doubled-blinded, placebo-controlled trial. The trial enrolled a total of 708 adult patients comparing the addition of capivasertib or placebo to standard of care, fulvestrant. The median progression-free survival was 7.2 months for capivasertib-fulvestrant versus 3.1 months for placebo-fulvestrant (hazard ratio, 0.50; 95% CI, 0.38-0.65; P < 0.001). Common adverse events included rash and diarrhea.

Content Update

April 19, 2023

Elacestrant Approved for ER-Positive, HER2-Negative, ESR1 Mutated Breast Cancer: The estrogen receptor antagonist elacestrant is U.S. Food and Drug Administration-approved for the treatment of postmenopausal women and adult men with advanced or metastatic ER-positive, HER2-negative, ESR1 mutated breast cancer who have progressed following at least one prior endocrine treatment. An open label phase 3 trial enrolling a total of 477 adult patients compared elacestrant to standard of care (SOC) endocrine monotherapy. Patients were randomized without regard to mutation status, and 48% of patients had an ESR1 mutation. Elacestrant significantly reduced the risk of progression or death compared with SOC by 45% in patients with ESR1 mutation (P = .0005). Common adverse events included fatigue, nausea, and arthralgia.

LEARNING OBJECTIVES

Upon completion of the chapter, the reader will be able to:

1. Detail epidemiological and clinical disparities of the disease.

2. Analyze risk factors associated with, and strategies that can modify the risk of, developing breast cancer.

3. Summarize the surrogate definitions of the intrinsic breast cancer subtypes.

4. Recognize signs and symptoms related to early and late stages of the disease.

5. Distinguish between good and poor prognostic factors.

6. Determine treatment goals for early-stage, locally advanced, and metastatic breast cancers.

7. State the rationale for inclusion of adjuvant and neoadjuvant therapies.

8. Describe the relevance of hormone, HER2, and PD-1 receptors.

9. Discuss the benefits and risks associated with various therapies.