Implication of total tumor size on the prognosis of patients with clinical stage IA lung adenocarcinomas appearing as part-solid nodules: Does only the solid portion size matter?

Stenotrophomonas maltophilia promotes lung adenocarcinoma progression by upregulating histone deacetylase 5

Introduction

Lung cancer is the leading cause of cancer death worldwide, and lung adenocarcinoma (LADC) is the most common lung cancer. Lung cancer has a distinct microbiome composition correlated with patients' smoking status. However, the causal evidence of microbial impacts on LADC is largely unknown.

Methods

We investigated microbial communities' differences in Formalin-Fixed Paraffin-Embedded tissues of ever-smoke (n = 22) and never-smoke (n = 31) patients with LADC through bacterial 16S rRNA gene high-throughput sequencing. Then nitrosamines 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung cancer mouse model and A549 cells were used to study the effect of Stenotrophomonas maltophilia (S. maltophilia) in LADC.

Results and Discussion

We found a significant increase of genus Stenotrophomonas in LADC tissues of patients with primary tumor size greater than 3 cm and never-smoker patients. We further found that intratracheal infection with S. maltophilia promoted tumor progression in the NNK-induced lung cancer mouse model. We performed RNA-seq analysis on lung tissues and found that S. maltophilia treatment drove inflammation and upregulated tumor associated cell signaling, including Apelin signaling pathway. Mechanistically, histone deacetylase 5 (HDAC5) gene expression was significantly upregulated in S. maltophilia treated groups, and was required for S. maltophilia induced cell proliferation and migration in LADC cell line A549. Therefore, we provide in vivo and in vitro evidence to demonstrate that S. maltophilia promotes LADC progression, in part, through HDAC5.

Tumor size, but not consolidation-to-tumor ratio, is an independent prognostic factor for part-solid clinical T1 non-small cell lung cancer

BACKGROUND

Tumor size and consolidation-to-tumor ratio (CTR) are crucial for non-small cell lung cancer (NSCLC) prognosis. However, the optimal CTR cutoff remains unclear. Whether tumor size and CTR are independent prognostic factors for part-solid NSCLC is under debate. Here, we aimed to evaluate the prognostic impacts of CTR and tumor size on NSCLC, especially on part-solid NSCLC.

METHODS

We reviewed 1366 clinical T1 NSCLC patients who underwent surgical treatment. Log-rank test and Cox regression analyses were adopted for prognostic evaluation. The "surv_cutpoint" function was used to identify the optimal CTR and tumor size cutoff values.

RESULTS

There were 416, 510, and 440 subjects with pure ground-glass opacity (pGGO), part-solid, and pure solid nodules. The 5-year overall survival (disease-free survival) for patients with pGGO, part-solid, and pure solid nodules were 99.5% (99.5%), 97.3% (95.8%), and 90.4% (78.9%), respectively. Multivariate Cox regression analysis indicated that CTR was an independent prognostic factor for the whole patients, and the optimal CTR cutoff was 0.99. However, for part-solid NSCLC, CTR was not independently associated with survival, even if categorized by the optimal cutoffs. The predicted optimal cutoffs of total tumor size and solid component size were 2.4 and 1.4 cm for part-solid NSCLC. Total tumor size (HR = 6.21, 95% CI: 1.58-24.34, p = 0.009) and solid component size (HR = 2.27, 95% CI: 1.04-5.92, p = 0.045) grouped by the cutoffs were significantly associated with part-solid NSCLC prognosis.

CONCLUSIONS

CTR was an independent prognostic factor for the whole NSCLC, but not for the part-solid NSCLC. Tumor size was still meaningful for part-solid NSCLC.

Narrative review of optimal prognostic radiological tools using computed tomography for T1N0-staged non-small cell lung cancer

Various radiological tools can predict the prognosis of non-small cell lung cancer (NSCLC). In this study, we evaluated the prognostic effect of different radiological tools such as whole tumor size (WTS), consolidation size (CS), consolidation tumor ratio (CTR), tumor disappearance ratio (TDR), mediastinal diameter (MD), and ground glass opacity (GGO) using high-resolution computed tomography (HRCT). We reviewed recent retrospective studies on the predictive effect of these radiological tools on disease-free survival (DFS) and overall survival (OS) in patients with T1N0-staged NSCLC. We searched PubMed and the British Library databases for the English literature published from January 2010 to December 2020 and generated a total of 32 publications (NSCLC, n=16; adenocarcinoma, n=16). The TNM classification version 7 was used in 18 studies, and version 8 in 14 studies. The evaluated radiological parameters were WTS, CS including T category, CTR, TDR, MD, presence of GGO, GGO ratio, and pure GGO. This review suggested that CS, MD, and the presence of GGO are optimal prognostic radiological tools for cT1N0-Staged NSCLC. CTR or TDR for part solid nodules (PSNs) is not a well-accepted prognostic factor. Further investigations are required to differentiate between benign scars and malignant components on HRCT and evaluate the prognosis of PSNs (1< CS ≤2 cm) with large WTS in the future.