The incidence of locally advanced breast cancer (LABC) is estimated at 10% of all breast cancer diagnoses. These cancers have a higher risk of recurrence than earlier stage disease⁶.

The definition of LABC varies across different randomized controlled trials. The Canadian Consensus for the definition of LABC is (pan Canadian consensus, Locally Advanced Breast Cancer Network):

This is consistent with the MD Anderson definition of Stage IIB or Stage III disease6. Patients with a diagnosis of LABC fall into one of two categories: those who have neglected seeking medical attention for a breast tumour for some time (these tumours often have a more indolent course of slowly growing disease over many months to years with no signs of metastases), and those with rapidly growing, aggressive disease, for whom timely management and coordination of care is key (see Pathway of Care Chart under Neoadjuvant Therapy, below). Neoadjuvant therapy with chemotherapy followed by surgery and radiotherapy is standard for all patients with LABC.  

There is a wide range of response rates, pathologic complete response, and overall survival associated with LABC, depending on the underlying intrinsic subtype of the cancer (triple negative and Her2+ having higher rates of pCR than luminal A and B subtypes)⁷. Intrinsic subtype is not routinely ascertained at diagnosis at present, but clinical and pathological factors that predict for likelihood a higher likelihood of a pathologic complete response are young age, high grade, basal-like or Her2+ breast cancer⁸.