P25.02 Lymph Node Metastasis of Malignant Pleural Mesothelioma

Abstract

Lymph node dissections and its efficacy are not well defined in malignant pleural mesothelioma (MPM) to date. To evaluate the progression of the disease, an appropriate mapping/zoning of lymph nodes is essential. We analyzed the frequency of lymph node metastases and prognosis of the patients with or without lymph node metastasis in MPM. We retrospectively retrieved the clinicopathological characteristics and medical courses of consecutive patients who had undergone surgery for MPM for curative intent. The lymph node was categorized according to lung cancer nodal chart: from zone 1 to zone 5. The cases with lymph nodes dissected only from one zone, with an incomplete evaluation of lymph nodes, a histological diagnosis other than epithelioid type, or cases without macroscopic complete resection were excluded in this analysis. From January 2007 and March 2019, a total of 241 patients received surgery for MPM. Of which 78 (32.4%) cases had a pathological evaluation of lymph node retrieved. There were 50 patients with no lymph node metastasis while 28 had metastases in lymph node resected. The median number of lymph node dissected was 6 (range 2-26). The five-year overall survival rate of patients without lymph node metastasis after diagnosis of MPM was 34.9% (C.I.19.6-50.1) and patient with positive lymph node metastasis was 10.7% (C.I. 0-22.1) (p<0.001). The limitation of this study is that lymph node dissection is not systematic and cannot be analyzed for each zone. There was a significant difference in the overall survival of the patients with or without lymph node metastases, which is compatible with the 8th ed of TNM classification for MPM. Prospective and planned lymph node dissection is most desired for MPM specific lymph node mapping.