Comparison of lung adenocarcinosis subtypes PET results and short period survival

Lung cancer is the most common cause of cancer death worldwide. The most common subtype of lung cancer is adenocarcinoma in many countries. In 2011, the study group of the International Association for the Study of Lung Cancer (IASLC) / American Thoracic Society (ATS) / European Respiratory Society (ERS) proposed a new classification for lung adenocarcinomas. In line with this recommendation, the World Health Organization (WHO) 4th edition published in 2015 included new changes. While this classification includes subtyping of adenocarcinomas, it emphasizes the prognostic significance of these patological subtypes. Positron Emission Tomography/Computed Tomography (PET/CT) used in the diagnosis of lung cancer is a method to measure the amount of fluorodeoxyglucose (FDG) absorption of suspicious lesions. This value is referred to as the Standard Uptake Value (SUV). SUV value >2.5 is considered suspicious for malignancy. In this study, in acinar, lepidic, micropapillary, papillary and solid subtypes of 152 adenocarcinoma cases of which the lungs were resected between January 2010 and January 2016; the relationship between SUV max values in PET-CT and survival was examined. A total of 152 (100%) operated patients, 112 (73.7%) male and 40 (26.3%) female, were included in the study. The mean age of the patients was 64.2 ± 8.6 (41-88). When the distribution of patients according to subgroups was examined; it was observed that there were 84 acinar (55%), 31 solid (20%), 23 lepidic (15%), 9 papillary (5%) and 5 micropapillary (3%). There was no significant difference in the distribution of subgroups according to age (p = 0.404). In the distributions of the sexes to the subgroups; acinar, solid, lepidic, papillary, and micropapillary were seen in men respectively; while subgroups of acinar, lepidic, solid, papillary and micropapillary were seen in women respectively. When the PET uptakes of the subgroups were examined, the difference between the groups was statistically significant (p=0.004); it was found that the greater uptake was in the solid (9,76) group, followed by micropapillary (8.98), acinar (8.06), papillary (5.82) and lepidic (4.23) subgroups. Patients participating in the study were followed for a mean of 40.2 ± 22.04 months, median of 36.62 (1-87); according to Kaplan-Meier life analysis, an interpretation of 59.65 ± 2.81 months (54.13-65.16 months) was made possible. When the distribution of patients according to TNM staging was evaluated; stage I was found to be 48.68% (n=74), stage II 25.0% (n=38), stage III 25.0% (n=38) and stage IV 1.31% (n=2). Survival between stages was statistically significant (p=0.001) when 1,3,5 years of survival was examined for all patients according to their stage; survival rates according to the stage were Stage I; 95%, 77%, 69%, Stage II; 92%, 72%, 10%, Stage III 80%, 45%, 9%, Stage IV 50%, 0%, 0% respectively. When the mean survival rate of the subgroups was examined; it was 57.4 months in acinar, 61.6 in lepidic, 44.5 in micropapillary, 66.0 in papillary and 59.7 in solid, was not statistically significant (p = 0.587). Conclusion: Although the most frequent subtype of lung adenocarcinomas was found as acinar in women and in men, the least frequent as micropapillary; statistically significant associations between age and sex were not achieved (p = 0.404). When the PET uptakes of the subgroups were examined, it was observed that the greater uptake was in the solid group and the least uptake was in the lepidic group (p = 0.004). Despite the fact that survival was determined to be statistically significant according to staging, no significant difference was found between survival of subgroups for the same stage. Keywords: Lung adenocarcinoma, classification, Positron Emission Tomography/Computed Tomography (PET/CT), survival