Lymph node metastasis from ductal carcinoma in situ with microinvasion

BACKGROUND. Widespread use of mammography has increased the detection of du ctal carcinoma in situ with microinvasion (DCISM) in pathology specimens. C urrently there is disagreement regarding the incidence of axillary metastas is from DCISM. The controversy centers on whether complete lymphadenectomy is indicated for axillary staging, given its morbidity and the reportedly m inimal rate of axillary involvement in these patients. Intraoperative lymph atic mapping and sentinel lymphadenectomy (SLND) may obviate complete axill ary lymph node dissection in selected breast carcinoma patients. In intraop erative lymphatic mapping, isosulfan blue dye is used to demonstrate the co urse of lymphatic flow from the breast tumor to the first draining or senti nel lymph node. This blue-stained lymph node is selectively excised for pat hologic examination; its tumor status is used to predict the tumor status o f the other axillary lymph nodes. The authors examined whether SLND would b e suitable for staging DCISM. METHODS. From February 1992 to January 1997, 14 patients with DCISM underwe nt intraoperative lymphatic mapping and SLND at the John Wayne Cancer Insti tute in Santa Monica, California. Clinical and pathologic data were prospec tively collected. RESULTS, Primary DCISM tumors ranged in size from 0.9 to 6.5 cm. Nine patie nts presented with mammographic abnormalities, two patients presented with Paget's disease and a palpable lesion, and three patients presented with pa lpable lesions. Two patients (14.3%) had tumor-involved sentinel lymph node s. One of these patients had two sentinel lymph nodes, both of which contai ned single cancer cells identified by immunohistochemistry. The other patie nt had 1 sentinel lymph node, in which a 0.3-cm metastasis was revealed by light microscopy. Completion axillary dissection was performed on both pati ents and revealed no further tumor positive lymph node metastases. CONCLUSIONS. SLND can detect lymph node micrometastases (tumor deposits <2 mm) in patients with DCISM. The clinical relevance of these micrometastases is unknown, but their existence shows that DCISM can involve the lymph nod es. Cancer 1999;85:2439-43, (C) 1999 American Cancer Society.