Title : Sentinel Lymph Node (SLN) biopsy in patients with head & neck and thyroid cancers
Abstract:
Introduction: Head and neck cancer is the common cancer amongst Indian males. Neck nodes are the best predictor of outcome in these cancers, and survival drops by 50% in node -positive necks. Neck dissections are therefore essential aspect of management of head and neck cancers. Sentinel lymph node(SLN) is the first lymph node draining a regional lymphatic basin. In case of established cancerous dissemination, it is postulated that the SLN is the target organs primarily reached by metastasizing cancer cells from the tumour.
Objectives: To assess the accuracy of sentinel lymph node biopsy in thyroid and head and neck malignancies.
Material and Methods: 35 FNAC/ Histology confirmed cases of thyroid and head and neck malignancies were evaluated after taking informed consent for enrolment in the study. Staging of the disease was done using USG/CECT . The patients were then take up for definitive surgery in form of surgery for the primary and neck dissection with a standardized technique. Intra-operatively Peri-tumoral 1ml of methylene blue dye was injected. The sentinel node/s (blue node/s) mapped and isolated after raising the superior flap. For thyroid malignancies dye was injected into the gland after raising flaps and identification of the parathyroid glands. Blue or sentinel lymph node were resected and sent for histology in separate container and assessed for the presence of metastatic deposits and compared with the final histology of all neck nodes sent after neck dissection along with the final histology of primary.
Result : The SLNB was a reliable predictor for the involvement of neck nodes in most of the cases. Identification rate using methylene blue dye alone was 93.33%. Over all Sensitivity, NPV & Accuracy was low however site specific Sensitivity, NPV & Accuracy was highest for the thyroid malignancy and lowest for carcinoma tongue.
Conclusion : Sentinel lymph node biopsy is reliable and accurate for assessing the status of neck nodes in thyroid malignancies. For oral malignancies (Ca GB sulcus /Buccal mucosa) role is still controversial. And for tongue malignancies SLNB is unreliable because of high skip metastasis.
