ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 Interestingly if the survival time was under 7 months the HR decreased with asbestos fibre concentration. The age of these patients was high, and they were probably not involved in fol- low up programs for the asbestos exposed possibly resulting in a delayed diagnosis. No effect of fibre type for the HR of mortality could be established. Conclusion: We found that the total asbestos fibre concentration increased mortality over follow up time in general except for an initial phase. The most common fibre types were anthophyl- lite and crocidolite, the usage of crocidolite has been relatively small. However crocidolite has been used for asbestos spray- ing explaining its prevalence in the lungs. Anthophyllite was recognized to be the sole fibre sizable population of patients with isolated anthophyllite exposure supporting its role in the pathogenesis of MPM. Funding: Several grants from the Helsinki University Hospital, the Finnish Cancer Foundation, the Finnish Work Environment Fund, and the Foundation of Finnish Anti-Tuberculosis Association have funded this study. OFP-06-008 Do different ALK positivity rates affect treatment response and prognosis in non small cell carcinoma of the lung? E. Yumuk*, A.A. Ağalar, D. Gürel, M. Arslan, M. Keser, Ç. Ulukuş, İ. Öztop *Department of Pathology, Dokuz Eylül University Faculty of Medicine, Turkey Background & objectives: Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase and therapeutic target in non-small cell lung cancer (NSCLC). We compared the therapeutic efficiency of targeted therapy between ALK-pos- itive cases near the threshold value (≥15%) and other ALK- positive cases. Methods: Our study included 73 patients with ALK-positive adenocarcinoma or NSCLC, 29 of whom were treated with ALK inhibitors and were followed up and treated at our centre. The percentage of ALK-positive tumour cells and the predominant sig- nal pattern (break-apart or single red) were obtained from pathol- ogy reports, and their relationship to prognosis was statistically evaluated. Results: The median age was 64.4±0.8(41-91). 52 were male (71.2%). The percentage of ALK rearrangements was 15-20% in 29, %15-25 in 47 cases. 51.4% of t he cases died. There was no statistical signif icance between the p e r c e n t a ge a nd s i gn a l p a t t e r n g r oup s a nd p r o gno s i s . Howeve r, t h e s i ngl e - re d s i gn a l domi n a n t g roup h a d a lower mortality rate than the break-apart dominant group (33.3%vs58.3%, p=0.056). The treatment response in the 15-20% ALK-positivity group was lower than in the ≥21% group (%14.3vs%35.7, p=0.314).<gwofw> The treatment response in the single red dominant group was higher than the break apart dominant group (62.5%vs26.3%, p=0.09). 15-25% group showed progression in 5.9 months, while the ≥26% group showed in 8.3 months.</gwofw> Conclusion: The mortality rate was lower and the treatment response rate was higher in the single red dominant group. Treat- ment response was lower in the group with 15-20% compared to the ≥21%group. The time to progression was 2.4 months shorter in the group with 15-25% compared to the ≥26%group. In conclusion, "borderline ALK-positive tumours" and cases with predominant break apart signal may have a worse prognosis. Nonetheless, these findings must be validated by larger-scale research with a greater number of cases. OFP-06-009 Pathologic assessment of resected stage III non-small cell lung cancer after neoadjuvant chemotherapy: identification of new prognostic factors F. Lunardi*, S. Tzorakoleftheraki, L. Vedovelli, F. Fortarezza, F. Pezzuto, A. Ferro, M. Schiavon, D. Gregori, F. Rea, G. Pasello, F. Calabrese *University of Padova, Italy Background & objectives: Non-small cell lung cancer (NSCLC) patients undergoing neoadjuvant chemotherapy followed by surgery represent an ideal clinical setting to discover prognostic/predictive factors. The aim of the study was to identify clinical/pathological features useful for a better patient stratification. Methods: Fifty-four stage III NSCLC patients were included between 2013 and 2021. Main clinical/laboratory data at the time of the diagnosis were recorded. All the morphological parame- ters of the surgical samples were evaluated, including the tumour bed and the new WHO grading for adenocarcinomas. Computer- assisted morphometrical quantification of fibrosis and inflamma- tion extension was performed. Survival analyses were done by Kaplan-Meier curves. Results: Longer disease-free survival (DFS) was found in patients with higher blood lymphocytes count (p=0.005) and higher fibrosis extension (p=0.05). Overall survival (OS) was related to gender (p=0.02), histotype (p=0.03) and pleural infiltration (p=0.05). When considering only adenocarcinomas, DFS was longer in patients with numerous blood lymphocytes (p=0.0006), lower WHO grades (p=0.01), lower proliferative index (p=0.01), less necrosis (p=0.004) and higher fibrosis extension (p=0.04). OS was related only to stage (p=0.02). A combined score that included lymphocytes, vascular infiltration, proliferative index, necrosis, fibrosis and inflammation, resulted more useful in stratifying patients for DFS(p=0.008). In adenocarcinomas the combined score seems to show a better performance when also WHO grading was included (p<0.0001). Conclusion: Different morphological aspects resulted crucial for the patient prognostic stratification, especially for DFS. The precise computer-assisted quantification of stromal components can overcome observer bias and inaccuracy, and the combination of different parameters will result in a more effective prognostic stratification of the stage III NSCLC patients. OFP-06-010 Asbestos body number in the lung of malignant pleural meso- thelioma resected by extrapleural pneumonectomy K. Okabe*, K. Hara, H. Miyamoto, N. Furukawa, T. Kimura *Bell Land General Hospital, Japan Background & objectives: Malignant pleural mesothelioma (MPM) is still dreadful disease, and has been recognized as related to asbestos inhalation. The aim of this study is to analyse the asbes- tos body number in the lung of MPM patients who underwent extrapleural pneumonectomy (EPP). Methods: Sixty consecutive MPM patients who underwent EPP from 2006 to 2019 were reviewed. Asbestos body quantifica- tion involved the digestion of 1-4 grams of lung tissue in bleach employing a modified Smith and Naylor method (Smith MJ, Nay- lor B. Am J Clin Pathol 1972; 58:250-254). In addition, age, sex, affected side, MPM type, cause of asbestos exposure, and prognosis were investigated. Results: The median age at EPP was 62 years old. 49 males and 11 females were operated. Right side was 30, and left side was 30. Epithelioid was 40, biphasic was 15, sarcomatoid was 2, and special variant was 3. 5-year survival and median survival of 30 S25