1% lymphazurin vs 10% fluorescein for sentinel node mapping in colorectal tumors

Hypothesis: Ten percent fluorescein may be successfully used as an alternative to 1% Lymphazurin (1% isosulfan blue; US Surgical Corp, North Haven, Conn) in sentinel lymph node (SLN) mapping for the accurate staging of colorectal tumors. Design: Review of prospectively gathered data. Setting: University-affiliated regional medical center Patients: Sentinel lymph node mapping was performed in 120 consecutive patients with colorectal malignancies. Interventions: The first 1 to 4 blue nodes detected within 5 minutes were designated as Lymphazurin-detected SLNs. The first 1 to 4 fluorescent nodes seen under the Wood light were designated as fluorescein-detected SLNs. Multilevel serial sections for hematoxylin-eosin and immunohistochemistry studies for cytokeratin were performed on all SLNs. Main Outcome Measures: Successful mapping, accuracy, skip metastasis, adverse reactions, occult micrometastases detection, and cost. Results: Mapping was successful using Lymphazurin in 99% of the patients vs 97% of the patients using fluorescein (P=.89). The accuracy of predicting nodal metastases with each tracer was 95.8% vs 93.1%, respectively (P=.82). The skip metastases rate was 4.2% for Lymphazurin vs 6.9% for fluorescein (P=.37). The 5 patients in whom nodal disease was only identified as occult micrometastasis in the SLNs had a total of 5 SLNs, all of which were identified by both tracers. No adverse reactions occurred. The cost for Lymphazurin was $99.00, while the cost for fluorescein was $2.10. Conclusions: With the exception of cost, there were no statistically significant differences between the 2 dyes. While easy availability and lower cost remain distinct advantages of fluorescein, Lymphazurin remains the gold standard. In patients with known hypersensitivity to Lymphazurin and when availability and cost are an issue, fluorescein may be used effectively for SLN mapping in colorectal tumors.