Most women with early-stage breast cancer have a higher chance of recovery. Each woman’s breast cancer has unique molecular characteristics which may reflect the tumor aggressiveness and the chance of cancer recurrence. Some of these women (~25%) may still experience a cancer recurrence/relapse after surgery. These recurrences often happen within 5 years of initial diagnosis. Hormonal therapy and chemotherapy are required to lower the risk of cancer recurrence after surgery. However, chemotherapy results in side effects and the absolute benefits may be low for patients with low chances of cancer recurrence — It is generally recommended for patients with less than 10% of distant recurrences to consider withholding chemotherapy. Prosigna is a new test which can reliably identify a patient’s 10-year risk of distant recurrence and may inform on whether chemotherapy is required for post-surgery.