Dermal lymphatic emboli in inflammatory and noninflammatory breast cancer: a French-Tunisian joint study in 337 patients.

Background: We studied whether dermal lymphatic emboli (DLE) add independent prognostic information to the clinical definition of inflammatory breast cancer (IBC).

Patients And Methods: The study was performed in 2 centers, one each in France and Tunisia. For every patient with IBC, 1-3 patients with noninflammatory breast cancer (non-IBC) were included. All patients were to have a surgical tumor biopsy, including a sample of the skin surrounding the tumor. The endpoint was the risk of a relapse at 2 years, which was estimated using univariate and multivariate Cox models.

Results: Three hundred thirty-seven patients were included (150 in France and 187 in Tunisia). The IBC status was divided into 2 clinical categories according to the extent of inflammation in the breast (localized IBC, which was defined as clinical inflammation in the tumor area, vs. diffuse IBC, which was defined as inflammation of at least two thirds of the breast). In total, 57 patients presented with localized IBC, 71 with diffuse IBC, and 209 with non-IBC. Dermal lymphatic emboli were found in 7% of non-IBC cases, in 25% of localized IBC cases, and in 45% of diffuse IBC cases. We found a significant interaction between the presence of DLE and diffuse IBC (P = 0.01). In patients with diffuse IBC, the presence of DLE increased the risk of relapse 3-fold. Conversely, DLE were not associated with the risk of relapse in patients with non-IBC, nor in patients with localized IBC. In patients with diffuse IBC and no DLE, the risk of relapse was similar to that of patients with localized IBC.

Conclusion: A DLE status might be a useful prognostic indicator exclusively in patients with diffuse IBC. However, because all patients with localized and diffuse IBC generally receive similar types of treatment, additional information on the presence or absence of DLE will not have an impact on treatment practice.