Prognostic impact of the 2015 world health organisation classification of lung adenocarcinoma : a study in departement specialized in thoracic pathology.

BACKGROUND: The 2015 WHO classification of primary lung adenocarcinomas idendified not only new subtypes but also new prognostic groups. Solid and micropapillary adenocarcinomas are considered of bad prognosis, lepidici adenocarcinomas are considered of good prognosis and acinary and papillary ones are considered of intermediate prognosis. We aimed to assess the prognostic relevance of this classification through the experience of a specialized Department in Thoracic Oncology.

METHODS: We described a survival study about 101 patients presenting primary adenocarcinomas diagnosed between 2008 and 2011. Survival curves were compared using the Log-Rank test. In order to assess the prognostic impact of the classification, 3 groups were formes: group 1 included lepidic adenocarcinomas, le group 2 included acinary and papillary subtypes and group 3 included solid subtype. A univariate analysis was performed to assess the age, sex, size, vascular emboli, lymph nodes, pTNM, histologic subtypes, neoadjuvant treatment and adjuvant treatment. Multivariate analysis using COX model was performed.

RESULTS: There was no significant difference between the different subtypes. Besides, the multivariate analysis revealed the pTNM (p=0,02)  stage and the adjuvant treatment (p=0,007) as relevant prognostic factors.

CONCLUSION: Our results are discordant with those reported in the literature. It seems that including large series is necessary in order to assess this prognostic classification.