Sentinel node biopsy in anal cancer - a promising strategy to individualize therapy

In order to individualize the therapy in patients with anal cancer, we evaluated the applicability of the sentinel lymph node (SLN) concept for the staging of inguinal lymph nodes in these patients.

SLN mapping using the radiocolloid technique was performed in 12 patients with histopathologically proven anal cancer. Mean age of the 4 male and 8 female patients was 62 years (range: 37-83 years). All patients underwent injection of (99m)Tc-colloid (Nanocis) in 4 portions around the tumor followed by scintigraphy after 17 h and selective lymph node biopsy in case of nuclide enrichment. The nuclide-enriched lymph node was intraoperatively identified by a hand-held gamma-camera. Histopathological assessment of the harvested SLNs included serial sections and immunohistochemical staining.

Enrichment of radiocolloid in lymph nodes was seen in 10 of the 12 patients (detection rate: 83%). SLN biopsy was performed in 9 patients, one patient refused the SLN biopsy (SLNB). 4 patients revealed tumor-infiltrated sentinel lymph nodes including one patient with bilateral biopsy, who showed metastases unilaterally. The remaining 5 patients had no evidence of metastases in the excised SLNs.

It is feasible to evaluate the nodal status of the groin in patients with anal cancer using the radiocolloid technique. Preliminary results indicate a refined diagnostic work-up for anal cancer patients, potentially improving the results of clinical and sonographical examinations. Further application of the method may lead to an individualized treatment of patients with anal cancer.