ASCO Guideline – Adjuvant Systemic Therapy Decision Making for Early Stage Operable Breast Cancer

SUMMARY: Breast cancer is the most common cancer among women in the US and about 1 in 8 women (12%) will develop invasive breast cancer during their life time. Approximately, 246,660 new cases of invasive breast cancer will be diagnosed in 2016 and 40,450 women will die of the disease. Patients with early stage breast cancer often receive adjuvant therapy. The ASCO Clinical Practice Guidelines Committee endorsed a set of Cancer Care Ontario guideline recommendations that addressed the role of a range of patient and disease characteristics, in selecting adjuvant therapy for women with early-stage breast cancer. This guideline does not address the selection of optimal adjuvant chemotherapy regimens.

Guideline Question: Which patient and disease factors should be considered in selecting adjuvant therapy for women with early-stage breast cancer?

Target Population: Female patients who are being considered for, or who are receiving systemic therapy for early-stage invasive breast cancer (Stages I–IIA, T1N0–1, T2N0).


Decisions regarding adjuvant therapy should be based on relevant (either prognostic or predictive) information and consideration given to-

1) Lymph node status, T stage, Estrogen Receptor status, Progesterone Receptor status, HER2 status, tumor grade, and presence of tumor lymphovascular invasion.

2) Risk-stratification tools including Oncotype DX score (for hormone receptor-positive, N0 or N1mic or isolated tumor cell, and HER2-negative cancers) and Adjuvant! Online.

3) Patient age, menopausal status, and medical comorbidities.

For patients in whom chemotherapy would likely be tolerated and for whom chemotherapy is acceptable, adjuvant chemotherapy should be considered if the following characteristics are present:

1) Lymph node-positive tumor (at least one node with macrometastatic deposit > 2 mm)

2) Estrogen receptor-negative tumor (> 5 mm)

3) HER2-positive tumor

4) High-risk node-negative tumors (> 5 mm) and another high-risk feature

5) Adjuvant! Online 10-year risk of death from breast cancer > 10%.

Patients with node-negative early stage breast cancer with high risk features who should be considered candidates for chemotherapy include

1) Tumors > 5 mm

2) Grade III histology

3) Triple negative tumors

4) Lymphovascular invasion

5) Oncotype DX recurrence score associated with an estimated distant relapse risk ≥ 15% at 10 years

6) HER2-positive tumors

(The ASCO panel suggested an estimated distant relapse risk > 20% in this setting).

Patients with tumor size < 5 mm, node-negative tumors, and no other high-risk features, may not benefit from adjuvant chemotherapy.

Adjuvant chemotherapy may not be required in patients with HER2-negative, strongly ER-positive, and PR-positive breast cancer and any of the following additional characteristics: positive nodes with micrometastasis only (< 2 mm), or Tumor size < 5 mm, or Oncotype DX recurrence score with an estimated distant relapse risk < 15% at 10 years. (The ASCO panel suggested an estimated distant relapse risk < 10% at 10 years in this setting)

ASCO Panel Discussion Points

Areas that warrant further consideration include-

1) Tumor histology and adjuvant therapy recommendations

2) Risk-stratification tools and proposed Oncotype DX recurrence score thresholds to guide decisions about chemotherapy

3) Patient factors in decision-making.

The panel noted that some uncommon breast cancer subtypes (eg, tubular, mucinous) may have a favorable prognosis and that such histologic information may be relevant for making decisions regarding adjuvant chemotherapy. Additionally, factors such as Grade III disease and lymphovascular invasion generally should not be used in isolation in decision-making but considered within the overall clinical context.

Role of patient and disease factors in adjuvant systemic therapy decision making for early-stage, operable breast cancer: Henry NL, Somerfield MR, Abramson VG, et al. American Society of Clinical Oncology endorsement of Cancer Care Ontario guideline recommendations. J Clin Oncol 34:2303-2311, 2016