Sentinel node biopsy for oral and oropharyngeal squamous cell carcinoma in the previously treated neck

In patients with early stage oral or oropharyngeal squamous cell carcinoma (OSCC) sentinel node biopsy (SNB) is a reliable method to detect occult disease in the neck. However, patients with a history of surgery or radiotherapy in the neck may have aberrant lymphatic drainage caused by disruption of lymphatic channels. Therefore, treatment of the same levels at risk as in the primary setting may not be appropriate. The aim of our prospective observational study was to evaluate the clinical application of SNB in previously treated OSCC. Between 2003 and 2010 twenty-two patients were included. Lymph node mapping consisted of preoperative lymphoscintigraphy, SPECT/CT, intraoperative use of gamma-probe and patent blue. Endpoints were the sentinel node (SN) detection rate, unexpected lymphatic drainage patterns, negative predictive value and regional tumor control. 4/22 (18%) Patients were previously treated only on the contralateral site. The SN detection rate was 100% and unexpected drainage was found in 1/4 patients. The other 18 patients had ipsi- or bilateral previous neck treatment and a SN detection rate of 83%. The upstaging rate was 7% and 67% had unexpected lymphatic drainage patterns. The median follow-up was 22 months. Regional tumor control and negative predictive value were 100%. SNB in previously treated OSCC patients is feasible. SN detection is reliable and regional tumor control after staging by SNB is excellent. Moreover, SNB renders an assessment of the individual lymphatic drainage pattern, compensating for a potential variability after previous treatment of the neck.