236 The Safe Introduction of Sentinel Node Dissection in The Treatment of Vulval Cancer – Early Experience of A British Centre

Surgical treatment for early stage vulval cancer usually involves wide local excision of the primary tumour and inguinofemoral lymphadenectomy. Removal of the lymph nodes carries considerable morbidity. A technique that identified nodal metastases without block dissection of these glands could be of major benefit to both patient and hospital. Sentinel lymph node (SLN) dissection is established in the treatment of breast cancer. The use of radiolabelled colloid to identify SLN(s) in vulval cancer is sensitive with a low false negative rate. We describe the safe introduction of this technique to a British centre. After peritumoral injection of 99mTc-nanocolloid, early dynamic camera imaging followed by a later static scan was used to identify the distribution of SLNs. Intraoperatively, a handheld gamma sensitive system (Europrobe) was used to localise the SLN(s). Patent blue dye was used as a visual aid to localisation. The SLN(s) were removed for pathological assessment, which included multistep sectioning and cytokeratin immunohistochemistry. Completion inguinofemoral lymphadenectomy was performed to assess the accuracy of the technique. Sources were used to simulate predicted activity in a patient in order to train the surgeons with the system before use in theatre. Prior risk assessment and subsequent monitoring in theatre indicated that exposure to staff is minimal. The procedure was well tolerated and SLNs were successfully identified in ten patients with no false negative results. Subsequently, seven patients have now successfully undergone SLND alone as part of the European multicentre observational study.