Diagnosis of Lymph Node Metastasis in Colorectal Cancer by a Semi-dry Dot-blot Method

BACKGROUND/AIM

This study aimed to examine whether the semi-dry dot-blot (SDB) method can correctly identify metastasis to lymph nodes in colorectal cancer.

MATERIALS AND METHODS

A total of 200 dissected lymph nodes from 83 patients with colorectal cancer who underwent surgery between November 2013 and May 2016 were examined. Each lymph node was first examined by SDB using anti-pancytokeratin antibody (AE1/AE3). Pathological Stage I/II patients with a negative reaction were further analyzed by SDB using anti-cytokeratin 20 antibody (CK-20) to detect micrometastasis or isolated tumor cells.

RESULTS

The sensitivity, specificity, and accuracy of SDB using AE1/AE3 were 91.3%, 100%, and 98.0%, respectively. Five of 99 lymph nodes of pathological Stage I/II patients had a negative reaction to AE1/AE3, but were positive to CK-20, while 3 showed isolated tumor cells.

CONCLUSION

The SDB is a useful diagnostic tool to detect lymph node metastases in colorectal cancer.

Validation of a Novel Diagnostic Kit Using the Semidry Dot-Blot Method to Detect Metastatic Lymph Nodes in Breast Cancer: Distinguishing Macrometastases From Nonmacrometastases

BACKGROUND

The semidry dot-blot method is a diagnostic procedure for detecting lymph node (LN) metastases using the presence of cytokeratin (CK) in lavage fluid from sectioned LNs. We evaluated 2 novel kits that use newly developed anti-CK-19 antibodies to diagnose LN metastases in breast cancer.

PATIENTS AND METHODS

We examined 159 LNs dissected that we sliced at 2-mm intervals and washed with phosphate-buffered saline. The suspended cells in the lavage were centrifuged and lysed to extract protein. This extracted protein was used with a low-power and a high-power kit to diagnose LN metastasis. Diagnoses on the basis of the kits were compared with pathological diagnoses.

RESULTS

Of the 159 LNs, 68 were assessed as positive and 91 as negative in permanent section examination. Sensitivity, specificity, and accuracy of the low-power kit for detecting LN metastases was 83.8%, 100%, and 93.1%, respectively. Those of the high-power kit were 92.6%, 92.3%, and 92.5%, respectively. Combining the low- and high-power kit results, those for distinguishing macrometastases were 94.5%, 95.2%, and 95.0%, respectively. Diagnosis was achieved in approximately 20 minutes, at a cost of less than $30 USD.

CONCLUSION

The kits were accurate, fast, and cost-effective in diagnosing LN metastases without the loss of LN tissue.