Chapter 145: Breast Cancer

Update Summary

The following updates to this chapter were made on January 25, 2021:

• Early Breast Cancer (Stage I and II), Adjuvant Biologic or Targeted thearpy was updated to include information on pertuzumab, trastuzumab, and hyaluronidase-zzx

• Locally Advanced Breast Cancer (Stage III) section was updated to include information on ado-trastuzumab emtansine

• Metastatic Breast Cancer (Stage IV), HER2-Targeted Agents section was updated to include information on pertuzumab, trastuzumab, and hyaluronidase-zzxf and margetuximab-cmkb plus chemotherapy, tucatinib plus trastuzumab and capecitabine, neratinib plus capecitabine, or fam-trastuzumab deruxtecan-nxki

• Metastatic Breast Cancer (Stage IV), Mammalian Target of Rapamycin (mTOR) Inhibitors section was updated to include information on alpelisib

• Metastatic Breast Cancer (Stage IV), Chemotherapy section was updated to include information on sacituzumab govitecan-hziy and pembrolizumab

KEY CONCEPTS

• Breast cancer is usually diagnosed in the early stages when it is highly curable.

• Although controversial, regular screening mammography in women younger than 50 years of age is beneficial, and many studies demonstrate that annual or biennial screening mammography in women ages 50 to 74 years reduces the breast cancer mortality rate.

• Local therapy of early-stage breast cancer consists of modified radical mastectomy or lumpectomy plus external-beam radiation therapy. The surgical approach to the ipsilateral axilla may consist of a lymph node mapping procedure with sentinel lymph node biopsy or a full level I/II axillary lymph node dissection.

• Adjuvant endocrine therapy reduces the rates of relapse and death in patients with hormone receptor–positive early breast cancer. Adjuvant chemotherapy reduces the rates of relapse and death in all patients with early-stage breast cancer.

• The choice of the most appropriate chemotherapy, endocrine therapy, and anti-HER2 therapy regimen is complex and rapidly changes as results from ongoing randomized clinical trials are reported.

• Neoadjuvant chemotherapy and biotherapy are appropriate for selected patients with early breast cancer and most patients with locally advanced and inflammatory breast cancer followed by local therapy and further adjuvant systemic therapy as indicated.

• The goal of adjuvant and neoadjuvant chemotherapy is cure while the goal of chemotherapy in the metastatic setting is palliation.

• Anti-HER2 therapies and other biologic or targeted agents (eg, everolimus, cyclin-dependent kinase [CDK] inhibitors) in combination with chemotherapy or endocrine therapy have significantly improved outcomes for patients with metastatic breast cancer (MBC).

• Initial therapy of MBC in most women with hormone receptor–positive tumors should include endocrine therapy.

• About 60% of women with MBC will respond to chemotherapy regimens; anthracycline- and taxane-containing regimens are the most active.

Preclass Engaged Learning Activity

Create a summary table of anti-HER2 treatment options for patients treated in the adjuvant setting with HER2-positive breast cancer. Conduct a literature search and discuss their impact on ...