Pathological features and patterns of metastatic disease in locally advanced inflammatory and non-inflammatory breast cancer

Locally advanced primary breast cancer (LAPC) is associated with a high risk of metastatic disease in spite of multimodality treatment. The aim of this study was to describe and compare the patterns of metastatic disease of the non-inflammatory (nIBC) and inflammatory (IBC) breast cancer subtypes as detected by staging computed tomography scan of the chest, abdomen and pelvis (CTCAP).

Over a 29 month period, 97 patients underwent staging CTCAP for LAPC or IBC and were identified from the hospital's computerised radiology system. The formal staging CTCAP scan and initial core biopsy pathology reports were reviewed. Statistical analyses were carried out using Fisher's exact test or chi square test via an online analysis package ('SISA-Binomial').

Thirty-eight patients (39%) presented with IBC and 59 patients (61%) with nIBC. Out of 97 patients, 16 (16.5%) had metastatic disease at staging CTCAP. Of these, 10 of 38 patients (26%) of the IBC group had metastases compared to 6 of 59 patients (10%) of the nIBC group (P = 0.034). Metastatic disease was present within the lungs, pleura and lymph nodes, with no liver or bone metastases. However, compared to nIBC, IBC patients were more likely to present with pleural metastases (4 of 38 (10.5%) versus 1 of 59 (1.7%), P = 0.05), the majority presenting with bilateral pleural based nodules.

A distinct pattern of pleural metastatic disease has been shown in patients with IBC.