Inflammatory breast cancer or T4d tumours present with rapid development of swelling, redness and peau d'orange (skin edema), which is often mistaken for an infection and treated with antibiotics before the correct diagnosis is made. A breast mass may or may not be apparent or the breast may be diffusely involved, but the overlying skin involvement is visible on clinical exam. The mammogram may show a discrete mass, but often there is only diffuse increase in density and skin thickening.

Inflammatory breast cancer is a clinical diagnosis. As expected, there is much controversy in the literature with regards to the "true" clinical parameters that define inflammatory breast cancer. According to international expert panel⁴, at a minimum, the following clinical criteria are required:

The distinctive pathological finding is the involvement of the dermal lymphatic vessels by tumour cells, which results in the skin erythema and edema. A biopsy (either core or open) to confirm the diagnosis should include skin to allow for the examination of dermal lymphatics.

This subtype of breast cancer is rare. Estimates from US datasets (SEER) suggest an incidence in the US of 1-5%⁵. While the incidence has increased since the early 1980s, this stage of cancer remains uncommon.

Patients with inflammatory breast cancer (IBC) should receive neoadjuvant therapy with chemotherapy and radiotherapy with the aim to render the disease operable.

Response rates and overall survival rates in this population are typically lower than for other stages of disease, with reported pathologic complete response ranging from 18-40% and 5 year OS rates ranging from 35-55%⁴. More intensive chemotherapy regimens are associated with higher rates of response. Treatment options are outlined in the section Neoadjuvant Therapy, below. As this subtype of breast cancer is aggressive, rapidly progressive, and associated with a high risk of recurrence/mortality, it is recommended that NAT be started in patients with IBC as soon as possible (see Pathway of Care Chart under Neoadjuvant Therapy, below).

Inflammatory breast cancer is the most aggressive form of breast cancer with a median survival of 18 to 24 months, despite intensive combined modality treatment leading to a high initial response. Prompt initial referral to BC Cancer is strongly recommended for these patients. 

Inflammatory breast cancer should be managed like other inoperable locally advanced breast cancer (stage IIIB and C) with neoadjuvant therapy, as described below.