METASTATIC PATTERNS OF INVASIVE LOBULAR VERSUS INVASIVE DUCTAL CARCINOMA OF THE BREAST

Background. Many studies have analyzed the metastatic patterns of brea st carcinoma. However, very few studies have analyzed the differences in metastatic patterns of lobular versus ductal carcinoma. Methods. By use of our tumor registry, the metastatic sites of all invasive lobul ar and ductal breast carcinoma cases during an 18-year period (january 1973 to December 1990) were analyzed. Results. There were 2605 cases of invasive lobular and invasive ductal breast carcinoma. Lobular carc inoma accounted for 359 (14%) and ductal carcinoma for 2246 (86%) of t he cases. The percentage of patients with regional lymph node metastas is at diagnosis was not significantly different between the two groups . The rates of metastasis to all lymph nodes, liver, and central nervo us system were not significantly different. However, the rates of meta stasis to the gastrointestinal system (4.5% vs 0.2%), gynecologic orga ns (4.5% vs 0.8%), peritoneum-retroperitoneum (3. 1% vs 0.6%), adrenal glands (0.6% vs 0%), bone-marrow (21.2% vs 14.4%), and lung-pleura (2 .5% vs 10.2%) were significantly different (p < 0.05). Conclusions. Th e metastatic patterns of lobular and ductal carcinoma of the breast ar e different, with gastrointestinal system, gynecologic organ, and peri toneum-retroperitoneum metastases markedly more prevalent in lobular c arcinoma. Physicians should be aware of these different metastatic pat terns of lobular and ductal carcinoma of the breast.