Sentinel Node Biopsy in Early Oral Cancers a Tertiary Cancer Centre Experience

Elective neck dissection (END) is the standard of care in node-negative early oral cancers.

However, it is associated with morbidity predominantly of shoulder dysfunction. Moreover, nearly 55-70% are true node-negative and are over-treated with this approach. Attempts have been made to overcome this limitation and to identify true node-negative patients. Sentinel node biopsy has shown the highest diagnostic accuracy among all other options. The SN is the first echelon node that drains directly through the lymphatics from the primary tumour. The principle of SNB is based on the fact that since it is the first echelon node, it would be the first site of regional metastasis. Therefore, the metastasis is unlikely to involve other nodal levels if the SNB is negative. It is the standard of care in breast cancers and melanoma. The concept made its way into oral cavity tumours and has been explored for over a decade in this setting. The results of the multi-institutional trial by Civantos et al. reported a high NPV of 94% of this procedure in early oral cancers that were node negative. Since then, various meta-analyses have shown that SNB has a high NPV making it a strong diagnostic modality. Schilling et al. reported the 3-year results of SNB in oral cancers in a multicentric study comprising 415 patients. The authors successfully identified the SN in 99.5% of cases and reported an FNR of 14%, which was high. Despite this, the study showed a high 3-year-disease-specific survival of 94%. Recently published Phase III Randomized controlled trials have shown that the overall survival of sentinel node biopsy is comparable to END with lesser morbidity in shoulder dysfunction. The advantage of the procedure is that only 25-30% of the patients who are SNB positive need to undergo neck dissection, and it spares unnecessary neck clearance and hence limits the morbidity in the remaining 70-75% of cases. SNB is a suitable alternative to END and is recommended in standard guidelines. However, SNB has a learning curve, it is recommended that the process be standardized, and the team should perform adequate SNB, followed by the completion of neck dissection before sparing the neck based on SNB. Investigators have been doing SNB in their department to standardize the process following the publication of level I evidence. This study aims to analyze the diagnostic accuracy of the SNB performed to standardize the procedure at the investigator's institute.