The incidence and significance of micrometastases in lymph nodes of patients with ductal carcinoma in situ and T1a carcinoma of the breast

AimTo report the incidence and predictive value of positive axillary nodes in ductal carcinoma in situ (DCIS) and T1a carcinoma of the breast.MethodsCases from The Netherlands Cancer Institute were used to determine the incidence of lymph-node metastases. All consecutive patients with primary breast cancer that were treated between 1989 and 1998 and who had undergone axillary dissection were selected. Patients were identified with pure DCIS (n=71), DCIS with small invasion (n=12), invasive ductal/lobular carcinoma (IDC/ILC) ≤5 mm (n=18) or tubular carcinoma ≤10 mm (n=17). All archived lymph nodes of these patients were re-evaluated using immunohistochemistry (IHC).ResultsIn DCIS the incidence increased from 1.4% with routine staining to 11% with IHC. For DCIS with small invasion it was 0 vs 27%, respectively. In IDC/ILC sized 2–5 mm the incidence rose from 6 to 12% and in tubular carcinoma ≤10 mm from 0 to 12%. All but one of the immunohistochemically detected metastases were isolated tumour cells (n=9) or small (micro)metastases (n=4). Maximally two nodes per patient were affected. None of the patients with positive lymph nodes died during follow-up (mean 102 months).ConclusionsSurvival of our patients appeared not to be influenced by the finding of micrometastases in the lymph nodes by IHC. Immunohistochemistry of the sentinel node seems not contributive to further treatment in these patients.