SENTINEL LYMPH NODE BIOPSY AS A PROGNOSTIC TOOL IN EARLY ORAL CANCER USING METHYLENE BLUE DYE

Research Abstract

Using SLN biopsy allows for reducing the risk of occult lymph node metastases in T1/T2 oral cancer patients from 40% to 8%, in addition to excellent control of the neck Since metastasis to a regional node is the most important prognostic factor in early-stage oral squamous cell carcinoma (elective) lymphadenectomy has been advocated to improve tumor staging and possibly survival. However, this approach exposes patients to complications resulting from the procedure and has not been shown to improve overall survival in a minority of patients with nodal metastases; however, it may have benefit. The study reported here shows that SLNB is useful and reliable for patients with early oral cancer that can benefit from this method where SLNB should reduce unnecessary functional and esthetic complications for N0 patients by reducing the incidence or extent of neck dissection. However, further multi-institutional studies are needed with clinical application of SLNB for oral cancer patients. In most of the recent literatures on patients with cT1-T2, N0 tongue cancer who underwent SLNB, the follow-up time was approximately 1 to 3 years thus, it is difficult to observe the impact of this treatment on long-term survival. Moreover, in contrast to the recent literatures, our study was limited to patients with cT1-T2, N0 oral cancer (not just tongue cancer), which made our study more targeted. Frozen section biopsy followed by Immunohistochemistry increase the sensitivity and negative predictive value of SLN but its applicability in real time decision making is limited. It has been reported that SLNB with step sectioning and immunohistochemistry can improve the detection rate of micrometastases therefore, a rapid, accurate intraoperative test for the presence of metastatic disease in SLN may support widespread acceptance of SLNB in cases of SCC of the head and neck. None of the differences between watchful waiting and SLNB reached statistical significance, but SLNB tended to reduce the rate of regional recurrence. Therefore we recommend that SLNB be the management strategy for treating clinical N0 in early oral cancer. The benefits of SLNB in the treatment of early tongue carcinoma should be further evaluated. In terms of reducing morbidity, SLNB is attractive way to think about. Cervical lymph node excision, and the amount of dissection required is a different to a formal END. Operative times are consequently shorter and, by not sacrificing the great auricular nerve, sensory perception is preserved. Similarly, by not dissecting out the accessory nerve, the risk of altered shoulder function is also reduced. Surgical drains are small and removed generally on the first postoperative day as the risk of hematoma, seroma, or chyle leak are low SND continues to be an appealing surgical procedure. A better understanding of the patterns of nodal metastasis, the biology of the primary tumor, and prognostic factors of metastatic disease in the neck should clarify some of the issues related to extent of neck dissection required. Prospective randomized trials comparing SND to RND and in particular the role of postoperative radiation therapy and indications for its use following SND will be required to resolve some of these controversial issues. Methylene blue dye alone can be successfully used for SLN identification in early oral cancers with a good accuracy and sensitivity. This method will be of use especially in resource limited countries and centers where nuclear medicine facilities are not widely available

Research Keywords

Sentinel L.N in H& N, Early Oral Cancer, Prophylactic Neck Dissection.