Key Points
➤ Adjuvant chemotherapy improves disease-free survival (DFS) and overall survival
(OS) independent of age, nodal status, and estrogen receptor (ER) status.
• However, those with triple-negative and human epidermal growth factor receptor 2
(HER2)–positive breast cancer seem to derive the greatest proportional benefit from
systemic chemotherapy and biologic therapy.
➤ The potential benefits and risks need to be carefully weighed before rendering a
decision to administer chemotherapy.
• Comorbidities and burden of disease need to be considered for selection of optimal
regimens.
➤ Patients with HER2-positive breast cancer with pathologic invasive residual
disease at surgery following standard preoperative chemotherapy and HER2-
targeted therapy should be offered 14 cycles of adjuvant trastuzumab emtansine
(T-DM1) unless there is disease recurrence or unmanageable toxicity. (Strong
Recommendation; EB-B-H)
➤ Clinicians may offer any of the available and approved formulations of
trastuzumab, including trastuzumab, trastuzumab and hyaluronidase-oysk,
and available biosimilars. (Strong Recommendation; EB-B-H)
New Recommendations from 2021 Guideline Rapid
Recommendation Update
➤ Based on a secondary pre-defined analysis conducted by the FDA (https://www.
accessdata.fda.gov/drugsatfda_docs/label/2021/208716s006s007s008lbl.pdf),
two years of abemaciclib (150 mg twice daily) plus ET may be offered to patients
with HR-positive, HER2-negative, node-positive early breast cancer with a high
risk of recurrence and a Ki-67 score of ≥20% as determined by an FDA-approved
test. (Strong Recommendation; EB-B-M)
➤ The Panel also recommends, based on analyses reported by Harbeck N, et al.
that abemaciclib for two years plus ET for ≥5 years may be offered to the broader
intent-to-treat population of patients with resected, HR-positive, HER2-negative,
node-positive, early breast cancer at high risk of recurrence, defined as having
≥4 positive axillary lymph nodes, or as having 1–3 positive axillary lymph nodes
and one or more of the following features: histologic grade 3 disease, tumor size
>5 cm, or Ki-67 index ≥20%. (Strong Recommendation; EB-B-M)
Qualifying Statements: Although exploratory analyses suggested similar HRs in favor of
abemaciclib regardless of Ki-67 status, there were relatively few Ki-67 low tumors in monarchE.
When discussing treatment options with patients, the potential benefits (improved IDFS) should
be weighed against the potential harms (treatment toxicity, financial cost).
Treatment
