Patterns of metastatic breast cancer in relation to histological type

We have examined the clinical records fo 1238 patients with operable breast cancer to identify the sites of metastatic disease. Infiltrating ductal carcinoma (IDC) recurred more commonly in lung (P < 0.05), pleura (P < 0.05) and brain (P < 0.05), while infiltrating lobular carcinoma (ILC) more commonly metastasised to the bone marrow (P < 0.01) and peritoneum (P < 0.01). Bone involvement as the initial presentation of distant metastatic disease occurred in over 50% of women with ILC, significantly more commonly than in those with IDC (34%, P < 0.01). Survival was similar for the two groups, both from time of diagnosis and from time of development of distant metastases.