Prognostic value of sentinel node in oral cancer

In stage I oral squamous cell carcinoma, clinical examination and imaging techniques are unable to identify 60-90% of patients at risk of micrometastasis, while the sentinel node biopsy technique allows to avoid the morbidity of elective neck dissection in patients not actually affected by micrometastases.

Forty-one T1-T2N0 patients underwent lymphoscintigraphy after peritumoral injection of human albumin labeled with 99Tc. Focal areas of radiotracer uptake were marked on the skin preoperatively. The sentinel lymph node (SLN) was identified by the combined use of blue dye and gamma probe and subsequently removed. Complete neck dissection was then performed in all patients and the histological findings were compared with those of SLN biopsy.

The SLN was identified in 95% of the patients; in four cases (10%) two SLNs were isolated. In 18% of our patients the SLNs were located outside the expected drainage area. When the histology of the negative SLNs was compared with the pathological status of the neck dissection specimens no false negatives were found. Five SLNs in four patients contained micrometastases and were the only positive lymph nodes.

SLN biopsy can be a valuable staging technique in T2 and T2 oral cancer with uninvolved neck in patients whose lymphatic drainage of the neck has not been altered by previous surgery or radiotherapy. It provides reliable detection of micrometastasis, indicating which level(s) should be removed ipsilaterally or contralaterally, and allows the surgeon to accurately plan neck dissection, taking into consideration the pattern of lymphatic drainage of each individual patient. In this way unnecessary neck dissection and its morphofunctional sequelae can be avoided in a considerable number of patients.