A new study has reported that lobular breast cancer has a tendency to metastasize to more axillary lymph nodes than ductal breast cancer. Lobular lymph node metastases also tend to have a higher stage. However, these differences are not associated with a significant impact on prognosis.

The study was designed to compare axillary lymph node metastases in invasive lobular and ductal breast cancer patients. Lobular and ductal carcinoma have different morphologies (physical forms and structures), with distinct biological characteristics and clinical behavior. The study included 426 patients with lobular breast cancer and 820 grade-matched ductal breast cancer patients. The authors compared the axillary lymph node status of the patients. In addition, the pattern of nodal metastatic deposits and the proportion of involved nodes were analyzed in a subgroup of 246 cases.

Grade-matched lobular tumors were found to be associated with higher lymph node stage (13.1% of lobular and 4.5% of ductal breast cancer nodes were stage 3), higher absolute number of positive lymph nodes, and a higher proportion of positive nodes (0.46 in lobular breast cancer and 0.33 in ductal breast cancer). These differences persisted when analyzed according to tumor size. Nevertheless, lobular breast cancer and grade-matched ductal breast cancer were found to have similar rates of regional recurrence and breast cancer-specific survival. The authors comment that the study results further demonstrate that lobular breast cancer and ductal breast cancer are biologically distinct entities. The two types have different lymph node involvement patterns and lobular breast cancer has a tendency to metastasize to more nodes than ductal breast cancer. However, this difference was not associated with worse outcomes for lobular breast cancer patients.

Please see our article on lobular breast cancer prognosis for more information on factors that influence lobular breast cancer outcome.