2001 Abstract: 334 One Hundred Consecutive Cases of Sentinel Lymph Node Mapping in Early Colorectal Carcinoma: Detection of Missed Micrometastases
Abstracts 2001 Digestive Disease Week
# 334 One Hundred Consecutive Cases of Sentinel Lymph Node Mapping in Early Colorectal Carcinoma: Detection of Missed Micrometastases Thomas F. Wood, Sukamal Saha, Donald L. Morton, George J. Tsioulias, Roderick R. Turner, Decio Rangel, William Hutchinson Jr, Anton J. Bilchik, Santa Monica, CA, Flint, MI
Background: Almost one-third of patients with node-negative colorectal carcinoma (CRC) develop systemic disease. This implies that these patients have occult disease that is inadequately treated by surgery alone. We have coupled sentinel lymph node (SN) mapping and a focused pathologic examination to detect occult nodal micrometastases in CRC.
Methods: Since 1996, SN mapping was performed in 100 consecutive patients undergoing colectomy for CRC. Peritumoral injection of 0.5-1.0 cc of isosulfan blue dye was performed to demonstrate the SN(s). All lymph nodes in the resection specimen were examined by routine hematoxylin and eosin (H&E) staining. In addition, a focused examination of multiple sections of the SNs was performed using both H&E and cytokeratin immunohistochemistry (CK-IHC).
Results: Overall, SN mapping successfully demonstrated 1-4 SNs in 97/100 cases (97%). These SNs accurately reflected the status of the nodal basin as a whole in 92/97 patients (95%). All five of the false-negative cases occurred in T3/T4 tumors and 3 of the 5 occurred during the first 30 cases in the experience. Unexpected lymphatic drainage was encountered in 7 patients (7%) altering the operative approach. Twenty-six patients were node positive by routine H&E staining. An additional eighteen patients (18%) were upstaged by identification of occult nodal micrometastases missed on routine H&E sections but detected by multiple sections (5) or CK-IHC (13). The SNs were the only positive nodes in 19 cases.
Conclusions: Sentinel lymph node mapping may be performed in CRC with a high degree of success and accuracy. A focused pathologic examination of the SN detects micrometastatic disease missed by conventional techniques in a significant proportion of patients with early CRC and may be useful to stratify those who might benefit from adjuvant therapy.