The Sentinel Node Concept in Melanoma and Breast Cancer : Relevancy and Therapeutic Consequences

Metastasis of squamous cell carcinoma of the oral tongue

Squamous cell carcinoma of the oral tongue (SCCOT) is one of the most prevalent tumors of the head and neck region. Despite advances in treatment, the survival of patients with SCCOT has not significantly improved over the past several decades. Most frequently, treatment failure takes the form of local and regional recurrences, but as disease control in these areas improves, SCCOT treatment failures are occurring more often as distant metastasis. The presence of cervical lymph node metastasis is the most reliable adverse prognostic factor in patients with SCCOT, and extracapsular spread (ECS) of cervical lymph nodes metastasis is a particularly reliable predictor of regional and distant recurrence and death from disease. Decisions regarding the elective and therapeutic management of cervical lymph node metastases are made mainly on clinical grounds as we cannot always predict cervical lymph node metastasis from the size and extent of invasion of the primary tumors. Therefore, the treatment of these metastases in the management of SCCOT remains controversial. The promise of basing treatment decisions on biomarkers has yet to be fully realized because of our poor understanding of the mechanisms of regional and distant metastases of SCCOT. Here we summarize the current status of investigations of SCCOT metastases and the potential of these studies to have a positive impact on the clinical management of SCCOT in the future.

The sentinel node concept in head and neck cancer: solution for the controversies in the n0 neck?

BACKGROUND

The majority of patients with head and neck squamous cell carcinoma (HNSCC) who have a clinical N0 neck undergo neck dissection (ND) even though no lymph node metastases may be detected. With this background, our investigation critically analyzes the value of sentinel lymphadenectomy.

METHODS

Ninety patients with HNSCC, all staged with an N0 neck, underwent intraoperative 99mTc-radiolabeled detection of up to three hot nodes (SN1-3) during elective ND and primary site resection.

RESULTS

Sentinel lymphadenectomy (SN1-3) detected occult metastatic spread in 20 (22%) of 90 patients, whereas failure occurred in three of 90 patients. Metastatic spread was directed to level II in the majority (66.7%) of cases. If only the SN1 had been examined, the procedure would have failed in nine (39%) of 23 patients.

CONCLUSION

Sentinel lymphadenectomy correctly identified the stage of metastatic disease in 97% of patients in cases in which up to three sentinel nodes were identified. If only the lymph node with the highest tracer activity had been excised, 39% of cancer-positive necks would have been missed. Selective ND identified metastatic disease in the additional 3% of patients.

Sentinel node detection in N0 cancer of the pharynx and larynx

Neck lymph node status is the most important factor for prognosis in head and neck squamous cell carcinoma. Sentinel node detection reliably predicts the lymph node status in melanoma and breast cancer patients. This study evaluates the predictive value of sentinel node detection in 50 patients suffering from pharyngeal and laryngeal carcinomas with a N0 neck as assessed by ultrasound imaging. Following 99m-Technetium nanocolloid injection in the perimeter of the tumour intraoperative sentinel node detection was performed during lymph node dissection. Postoperatively the histological results of the sentinel nodes were compared with the excised neck dissection specimen. Identification of sentinel nodes was successful in all 50 patients with a sensitivity of 89%. In eight cases the sentinel node showed nodal disease (pN1). In 41 patients the sentinel node was tumour negative reflecting the correct neck lymph node status (pN0). We observed one false-negative result. In this case the sentinel node was free of tumour, whereas a neighbouring lymph node contained a lymph node metastasis (pN1). Although we have shown, that skipping of nodal basins can occur, this technique still reliably identifies the sentinel nodes of patients with squamous cell carcinoma of the pharynx and larynx. Future studies must show, if sentinel node detection is suitable to limit the extent of lymph node dissection in clinically N0 necks of patients suffering from pharyngeal and laryngeal squamous cell carcinoma.