detection rate), the propotion of pathologically positive results (malig- nancy rate) per patient and per node. The study project has been aprooved by the local ethic committee. Procedure description: one day before SLN biopsy, patients receive per- itumoral injections of Tc99 and Sienna+®. The surgeon uses both Sentimag and gamma probe to localize SLN. The process is being repeated after incision and all detected SLN are excised and assessed by histology. In case no SLN is identified or suspicious lymph node has been found the surgeon is obliged to perform standard inguinofemoral lymphadenectomy. Results: We found SLN in every case with both studied methods with equal average distribution (3.1 SLN per patient). SLN detection rate per patient was 100% in both techniques. Nodal detection rate was either equal for ferromagnetic and for radioactive tracer (95,7%). Pathological analysis showed squamous carcinoma of the vulva with the average tumour size of 29.7 mm. 4 patients had no metastases in SLN (pN0), 1 had micrometa- stasis found (pN1) and 3 macrometastases(pN2). Malignancy detection rate per patient was 100% positive with both methods. Malignancy rate for nodes was 29% and for patients - 50% . Conclusions: We consider the new method of SLN detection with the use of ferromagnetic injection in vulvar cancer patients as reliable, efficient and safe. However these promising data are few thus SARVU study must be continued to proove the efficacy of a novel technique of Sentimag/ Sienna+® in SLN detection in vulvar carcinoma. Conflict of interest: No conflict of interest. 604 SENTINEL LYMPH NODE BIOPSY IN THE MANAGEMENT OF PAPILLARY THYROID CARCINOMA E. Bakalinis , G. Dori, E. Papantoni, N. Perrakis, K. Ntatsis. Metaxa Cancer Hospital, 2nd Surgical Clinic, Piraeus- Attica, Greece Background: Papillary Thyroid Carcinoma (PTC) predominantly metasta- sizes into regional lymph nodes and is associated with significant inci- dence of occult central and lateral nodal metastases as high as 50%. No evidence exists in favor of prophylactic neck dissection for PTC. Sentinel Lymph Node (SLN) biopsy helps to identify patients who might benefit from lymph node dissection in breast cancer and localized melanoma. The purpose of this study is to assess the potential of SLN biopsy in the se- lection of patients with PTC who would benefit from cervical lymph node dissection. Materials and methods: A systematic literature search conducted in PubMed for original articles, systematic reviews and practice guidelines regarding the use of SLN biopsy in patients with PTC, using the keywords: PTC, SLN and neck dissection. Results: In total 8 articles were evaluated and their results and conclusions were summarized in the current paper. Multiple techniques for SLN mapping such as dyes like methylene blue, patent blue and nano-carbon or radiotracers are described. Intraoperative SLN identification rate, SLN metastatic rate and false negative rate were 92.1%, 33.6% and 25.4% respectively. Lymph node metastasis were found in the central (23%) and lateral compartments (10.6%). Conclusions: Sentinel Lymph Node biopsy may have a role in the man- agement of patients with clinically node negative PTC. Radioguided SLN biopsy is a safe and promising technique which improves node staging, thus enabling better selection of patients eligible for radioiodine therapy and reducing disease recurrence. More prospective trials are needed to further assess whether SLN biopsy belongs in the armamentarium against PTC. Keywords: papillary thyroid carcinoma, sentinel lymph node Conflict of interest: No conflict of interest. Poster Session Soft Tissue Sarcoma 606 MULTIDISCIPLINARY MANAGEMENT OF SOFT TISSUE SARCOMAS: EXPERIENCE FROM PAKISTAN R. Sayyed 1 , S. Niazi 2 , A. Ahmed 3 , A. Haider 4 , F. Buriro 5 . 1 Patel Hospital, Surgical Oncology, Karachi, Pakistan; 2 Dow University of Health Sciences, Surgical Oncology, Karachi, Pakistan; 3 Kiran Hospital, Oncology, Karachi, Pakistan; 4 The Aga Khan University, Medical College, Karachi, Pakistan; 5 Patel Hospital, Plastic Surgery, Karachi, Pakistan Background : Soft tissue sarcomas (STS) are best managed in an expert centre. Expertise and centralized care may not be easily available in resource limited settings. We describe our efforts to develop a STS service in Karachi, Pakistan. Material and methods : A group of surgeons with common interest in STS got together to discuss and manage STS cases. The STS cases were worked up with cross-sectional imaging and biopsy. All clinical data were dis- cussed with an international sarcoma expert who helped with the decision making process as well as surgical planning. Results : Between January and April 2018, 7 patients with STS were reviewed in our service. There was one patient that presented for primary treatment, 3 patients had inadequate excision elsewhere requirin re- excision, while 3 patients had recurrent STS. Tumor location was trunk in 3 patients, retroperitoneum in 2 patients and extremity in 2 patients. One patient had angiosarcoma, while Malignant peripheral nerve sheath tu- mor, liposarcoma and synovial cell sarcoma was seen in two patients each. Treatment decisions were made as per discussion with expert sarcoma surgeon. Three patients underwent resection with clear margins, three patients went elsewhere for resection and one patient was advised sys- temic chemotherapy followed by reassessment. Conclusions: In the face of lack of expertise and training in management of STS and limited resources, collaboration and mentoring by an international expert has helped in treatment decisions as well as learning of the team in overall management of STS. Conflict of interest: No conflict of interest. 607 ARE ALL MALIGNANT PERIPHERAL NERVOUS SHEATH TUMORS THE SAME? e ANALYSIS OF PROGNOSTIC FACTORS A. Ferreira 1 , A. Sousa 2 , M. Afonso 3 , P. Martins 2 , A. Ferreira 4 , S. Conde 5 , F. Videira 2 , A. Moreira 2 , J. Guimar~ aes 2 , M. Ribeiro 6 , J. Abreu de Sousa 2 . 1 Local Health Unit of Litoral Alentejano, Department of Surgery, Santiago do Cac em, Portugal; 2 Portuguese Institute of Oncology, Department of Surgical Oncology, Porto, Portugal; 3 Portuguese Institute of Oncology, Department of Pathology, Porto, Portugal; 4 Portuguese Institute of Oncology, Department of Medical Oncology, Porto, Portugal; 5 Portuguese Institute of Oncology, Department of Radiation Oncology, Porto, Portugal; 6 Portuguese Institute of Oncology, Department of Plastic and Reconstructive Surgery, Porto, Portugal Background: Malignant peripheral nerve sheath tumors (MPNST) are rare sarcomas thought to be of neural origin from the perineural cells, frequently associated to neurofibromatosis type 1 (NF1) and are a partic- ularly challenging group of sarcomas to treat. As they originate from the neural tissue, malignant cells have a direct access to neural infiltration and dissemination. Prognosis is generally poor, with a high grade nature and high rates of recurrence and metastatic dissemination. We sought to determine prognostic factors regarding this disease using a group of pa- tients treated at our center. Material and Methods: The authors have performed a retrospective analysis of patients treated at our center with the diagnosis of MPSNT between 2008 and 2017. Demographic, pathologic and treatment data were determined, and prognostic factors were analyzed using de Kaplan- Meier method. Results:A total of thirty-three patients were identified. There was an equal distribution of gender (17 women and 16 men) with a median age of 44 years. Ten patients had NF1. Most lesions were located in the lower limb (24 cases) and the second most commonly involved area was the head and neck (8 patients). At presentation, only twenty-seven patients had potentially resectable locoregional disease with a median tumor size of 9 cm. Neoadjuvant therapy was used in six cases (18.2%). Ten patients were referred to our center after surgery. Formal nerve resection during surgery was described in 11 patients (33.3%). Only 21 patients had negative mar- gins after the first surgery (63.6%). In most cases, MPSNT was classified as Abstracts / European Journal of Surgical Oncology 45 (2019) e25ee158 e152