Importance of sentinel lymphatic node biopsy in detection of early micrometastases in patients with cutaneous squamous cell carcinoma.

BACKGROUND: Cutaneous squamous cell carcinoma (CSCC) is the second most common malignant skin cancer with a tendency to spread through the lymphogenic pathway. Metastases are found in 2-6% of cases. The aim of this study was to determine CSCC micrometastases when non-invasive examination methods do not detect them.

METHOD: A total of 88 patients were included in the study with clinically diagnosed, histologically confirmed CSCC and no distant or regional lymph node metastases detected during instrumental tests. The patients were grouped into low- and high-risk CSCC groups. They underwent one-stage surgery - radical tumour excision and sentinel lymph node/nodes biopsy (SLNB). Significance level of 0.05 was chosen for testing statistical hypotheses.

RESULTS: One hundred and fifty-three sentinel lymph nodes (SLNs) were detected and excised in 88 patients. Micrometastases were found in five SLNs of three patients with high-risk CSCC. The rate of micrometastases was 3.4%; however, in the high-risk group it was 6.5%. The mean diameter of CSCC with micrometastases in SLN was 5.6 ± 3.5 cm, and that without micrometastases was 1.5 ± 1.1 cm (p = 0.003). The depth of CSCC according to Breslow in the patients with detected micrometastases in SLN was 3.5 ± 1.2 mm, and that without detected micrometastases was 2.2 ± 1.4 mm (p = 0.047). Patients with micrometastases in sentinel lymphatic nodes underwent radical lymphadenectomy. There was neither recurrence of CSCC metastases in regional lymph nodes nor distant metastases during the research period detected.

CONCLUSIONS: In patients with CSCC the rate of micrometastases directly correlates with the depth and diameter of the tumour. In patients with high-risk CSCC the rate of micrometastases is 6.5%.