P26. Well differentiated neuroendocrine tumors of the lung—our experience

Well differentiated pulmonary neuroendocrine tumors [low (G1) and intermediate grade (G2) neuroendocrine tumors according to WHO 2010, abbreviated as G1/G2 NET] represent minor but clinically important part of lung neoplasms. More often known as typical and atypical carcinoids, both entities account for 1-2% of pulmonary tumors. Because of their rather favorable prognosis—G1 NET 5-year survival over 90%, G2 NET 40-60%—and low incidence, they were in past on the margins of attention. However, with advances in molecular genetics and biology sciences, new therapeutic ways are emerging, such as mTOR kinase inhibitors, anti-angiogenic monoclonal antibodies or other, still experimental drugs interfering with PI3K/Alt/mTOR kinase signal pathway, as well as long-acting somatostatine inhibitors with attached radioisotopes. Our poster presents ten year experience with GR/G2 NET on our Pulmonary department and befriended Clinic of T. Bati. We consecutively followed up 42 patients with G1 NET and 22 patients with G2 NET for average period of 4.4 years (G1 NET, median follow up 4.0 years), respectively 4.7 years (G2 NET, median 3.9 years) with histologically verified diagnosis of primary typical/atypical carcinoid of the lung. Population characteristics, staging, tumor marker levels, rate of paraneoplastic syndromes, treatment, reccurence, 5-year and 10-year survival (where possible) and occurrence of duplicite malignancies were evaluated. Most patients (n=52) were treated by thoracic surgery methods, endobronchial laser therapy was performed in small subset of patients (n=8) with recurrence rate 25%. Our observations confirm excellent prognosis of G1 NET (none of patients died because of carcinoid tumor in 5-year follow up, however two died because of duplicite malignancies), and worse prognosis of G2 NET (5-year survival 64%, 10-year survival 41%). We would like to also draw attention to new therapeutic possibilities in treatment of pulmonary G1/G2 neuroendocrine tumors.