Abstract 1118P
Background
Well-differentiated lung neuroendocrine tumours (NETs), classified as typical (TC) and atypical (AC) carcinoids, are 30% of NETs. Angiogenesis plays an essential role in the development and progression of NETs. In this context, a higher vascular network represents a marker of differentiation, with positive prognostic implications. This phenomenon is called ’neuroendocrine paradox’, with vascularization being inversely related to tumour aggressiveness. No data are available about the role of angiogenesis in left vs right-sided lung NETs.
Methods
We have retrospectively evaluated microvessel density (MD) by immunohistochemical staining for CD34 positive endothelial cells & through hot spot method in peritumoral and intra-tumoral areas, comparing right and left lung parenchyma in 53 lung NETs. We collected patients’ data and analysed them through SPSS system.
Results
Median age was 66 years (39-81), 56.6% males, 26.4% smokers, 24.5% AC, 40.5% left-sided tumours, 69.8% TNM stage I at diagnosis. Mitotic count was <2/10 HPF in 79.2%, absence of necrosis in 71.7%; 39.6% with a Ki67≤2%, 52.8% with a Ki67 of 3-19%. NE markers (synaptophysin, chromogranin A,TTF-1) were positive in 92.5%, 75.5% and 35.8%. Median follow-up was 23 months (0.7-323), 2-years and 5-years PFS rates were 100% and 93.8%, respectively. 2-years and 5-years OS rates were both 96.2%. MD was evaluated in 41 cases, 19 left-sided and 22 right-sided tumours. The median values were higher in right than left parenchyma (MD: 252 vs 195, number of vessels: 759 vs 529, average vessel area 202 vs 182). We detected a statistically significant association between 18 FDG positivity and lower MD (p=0.001) as well as with lower number of vessels (p=0.003).
Conclusions
This study suggests a biological rationale for a different angiogenesis according to primary tumour side in left vs right parenchyma for lung NETs. 18FGD PET positivity (a well-known poor prognostic factor for NETs) correlated with lower vascularization. Left-sided tumours were associated with lower MD, number of vessels and average vessel area, with potential prognostic impact. These data could support NET paradox also in lung parenchyma, paving the way for a more personalized treatment for lung NET.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.