Spread Through Air Spaces Is a Prognostic Factor in Sublobar Resection of Non-Small Cell Lung Cancer

Tumor Spread Through Air Spaces in Non-Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

A series of studies have assessed the clinicopathological features and prognostic impact of spread through air spaces (STAS) in non-small cell lung cancer (NSCLC) bringing conflicting findings so far. We performed a systematic review and meta-analysis to synthesize the available evidence regarding to the prognostic value of STAS in NSCLCs.

METHODS

Studies were identified by searching databases including PubMed, EMBASE, Web of Science, and Cochrane Library up to August 2018 without language restrictions. Results of these searches were filtered according to a set of eligibility criteria and analyzed in line with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines.

RESULTS

A total of 3,754 patients from 14 studies were selected for the present study. The pooled results suggested that presence of STAS was associated with worse recurrence-free survival (hazard ratio [HR], 1.975; 95% confidence interval [CI], 1.691 to 2.307; p < 0.001) and overall survival (HR, 1.75; 95% CI, 1.375 to 2.227; p < 0.001) in NSCLCs. Subgroup analysis by histology type indicated the presence of STAS was significantly associated with inferior recurrence-free survival in resected lung adenocarcinoma (n = 7; HR, 2.288; 95% CI, 1.843 to 2.840; I² = 7.80%), lung squamous cell carcinoma (n = 3; HR, 1.622; 95% CI, 1.279 to 2.056; I² = 0%), and lung pleomorphic carcinoma (n = 1; HR, 4.76; 95% CI, 1.168 to 19.398). Additionally, a number of clinicopathological characteristics indicating STAS in NSCLCs are summarized.

CONCLUSIONS

Our study indicates that tumor STAS was a potentially significant prognostic predictor for surgical patients with NSCLCs. The prognostic impact of STAS present in the resection margin remains undetermined. Further large-scale prospective studies are warranted to confirm the prognostic significance of STAS in patients with NSCLCs.

Prognostic Impact of Tumor Spread Through Air Spaces in Sublobar Resection for 1A Lung Adenocarcinoma Patients

BACKGROUND

This study aimed to clarify differences in the prognostic impact of tumor spread through air spaces (STAS) in lobectomy versus sublobar resection (SR). The study also investigated the frequency and significance of STAS in residual lung segments.

METHODS

This study identified 752 patients with p-stage 1A non-small cell lung cancer (NSCLC) from 2010 to 2012. Recurrence-free survival (RFS) and overall survival (OS) were compared. For proactive simulation of SR, 100 consecutive lobectomy specimens of p-stage 1A NSCLC were selected.

RESULTS

The study found STAS in 182 (28.7%) of 634 lobectomy cases and 43 (36.4%) of 118 SR cases. Multivariable analysis showed that STAS was not a prognostic factor in the lobectomy group, but showed a significantly worse prognostic effect for the SR group (RFS, P < 0.001; OS, P < 0.001). In 9 of 100 simulated cases, STAS occurred in residual lung segments. The patients with T1c category disease had a significantly increased risk for the development of STAS in residual lung segments (P = 0.033).

CONCLUSIONS

For patients with p-stage 1A lung cancer who have undergone SR, STAS is a prognostic indicator of poor outcomes. The presence of STAS does occasionally exist in the residual lung segments.

Predictive value of a prognostic model based on pathologic features in lung invasive adenocarcinoma

OBJECTIVES

Tumor spread through air spaces (STAS) was recently reported as a novel risk factor for the prognosis of patients with resected lung adenocarcinoma that indicates invasive tumor behavior. The purpose of this study was to build a prognostic model consisting of STAS and other pathologic features including visceral pleural invasion (VPI), vascular invasion (VI) and histological subtype (HS) in lung invasive adenocarcinoma.

MATERIALS AND METHODS

A total of 289 patients with resected lung invasive adenocarcinomas ≤4 cm were analyzed retrospectively to evaluate the potential prognostic value of STAS, VPI, VI and HS for recurrence-free survival (RFS) and overall survival (OS).

RESULTS

STAS was observed in 143 patients (49.5%). Univariate and multivariate analysis showed that STAS, VPI, VI and HS were significant prognostic factors for poorer RFS and OS. Thus, a prognostic model including STAS, VPI, VI and HS was built using the results of the multivariate analysis. Nomograms were developed to predict the 5-year RFS and OS. The concordance index (C-index) of the prognostic model was 0.8122 for predicting 5-year RFS and 0.8539 for predicting 5-year OS in the internal validation. Moreover, the calibration curves for the 5-year RFS and OS showed that the nomograms were calibrated well. In addition, a similar predicted capability of the prognostic model was observed in the validation cohort.

CONCLUSION

STAS, VPI, VI and HS were significant prognostic factors for poorer RFS and OS. The prognostic model including STAS, VPI, VI and HS could effectively predict prognosis.

Prognostic Impact of Tumor Spread Through Air Spaces in Non-small Cell Lung Cancers: a Meta-Analysis Including 3564 Patients

Surgical resection is the most effective treatment for early stage lung adenocarcinoma. However, the rate of 5-year postoperative recurrence reaches 30%, Spread Through Air Spaces(STAS) is a recently described novel invasive pattern of lung cancer, According to the 2015 WHO classification. STAS is defined as"micropapillary clusters, solid nests, or single cells spreading within air spaces beyond the edge of the main tumor, However, the prognostic role of STAS in lung cancer is not known, The aim of the current study is to evaluate the association between STAS and clinical outcome of lung cancer patients after surgical resection through a meta-analysis. Systematic research was conducted using three online databases to search for studies published before August 1, 2018. The 5-year RFS and OS for non-small cell lung cancer patients after surgical resection with or without STAS were compared. The studies were selected according to rigorous inclusion and exclusion criteria. Meta-analysis was performed using hazard ratio (HR) and 95% confidence intervals (CIs) as effective measures. Included in our meta-analysis were 12 studies, published from 2015 to 2018, with a total of 3564 patients. Our results clearly depicted that the presence of STAS predicted a worse outcome for 5-year RFS with the combined HR of 1.84(95% CI: 1.59-2.12). Meta-analysis of these 8 studies showed that patients with the presence of STAS were associated with shorter 5-year OS (the pooled HR:1.78, 95% CI: 1.51-2.11). This meta-analysis illuminated that the presence of STAS might be a unfavorable prognostic factor for patients with NSCLC. it should be paid sufficient attention and recorded in pathologic reports, which can indicate treatment choice and prognosis of patients. In future, more studies with well-designed and large-scale are needed to confirm the conclusion.

Spread through air spaces in lung cancer patients is a risk factor for pulmonary metastasis after surgery

BACKGROUND

Spread through air spaces (STAS) is regarded as a significant risk factor for lung cancer recurrence. STAS consists of micropapillary clusters, solid nests, or single cells beyond the edge of the tumor into air spaces in the surrounding lung parenchyma. However, the patterns of lung cancer recurrence have not been clarified in patients with STAS. The aim of this study was to explore STAS and recurrence patterns in patients who underwent lung cancer surgery.

METHODS

Between January 2000 and December 2017, a total of 1,426 patients underwent complete resection of lung cancer. We studied 848 patients with pathological stage I disease who underwent surgery. Recurrence patterns and recurrence-free rates were determined from pathological findings, particularly the presence of STAS. Locoregional recurrences included surgical margin recurrences, hilar and mediastinal lymph node metastases, ipsilateral lobe metastases, and pleural dissemination, whereas distant recurrences included extrathoracic organ and contralateral lobe metastases.

RESULTS

STAS was observed in 139 of 848 (16.4%) cases. Recurrences developed in 108 (12.7%) cases: locoregional recurrences in 76 (9.0%), distant metastases in 27 (3.2%), and both in 5 (0.6%) cases. Among recurrences, pleural dissemination developed in 12 (1.4%) and pulmonary metastases in 46 (5.4%) cases. Five-year recurrence-free rates were 65.4% among patients with STAS and 89.0% among patients without STAS. Univariate and multivariate analyses revealed that STAS was a significant risk factor for recurrence (P<0.001), particularly locoregional recurrence (P=0.005). In addition, STAS was a significant risk factor for pulmonary metastasis (P=0.009).

CONCLUSIONS

Among pathological stage I patients who undergo complete resection of lung cancer, patients with STAS tend to develop locoregional recurrence and pulmonary metastases.

Significance of spread through air spaces in early-stage lung adenocarcinomas undergoing limited resection

Background

In early‐stage lung adenocarcinomas, spread through air spaces (STAS) are reported to be a prognostic factor in patients who have undergone sublobar resection, but not lobectomy. In contrast, reports have also shown that STAS is significantly associated with poor survival outcomes after lobectomy, but not after limited resection. Thus, the prognostic impact of STAS differs according to published reports.

Methods

A total of 82 patients with early‐stage adenocarcinomas who underwent limited resection and whose STAS status could be examined were enrolled in this retrospective study. We evaluated the association between STAS and clinicopathological characteristics and postoperative survival.

Results

Among 82 patients, 31 (37.8%) were positive for STAS, while 51 (62.2%) were negative. STAS was significantly associated with advanced tumor stage (P < 0.01), lower histological differentiation (P = 0.01), and the presence of pleural invasion (P = 0.01). Patients with STAS had significantly shorter recurrence‐free survival (RFS) and overall survival (OS) than those without STAS (P < 0.01 and P = 0.02, respectively). According to multivariate analysis, positivity for STAS was an independent prognostic parameter for RFS (P < 0.01), but not OS (P = 0.45). Three patients who developed surgical margin recurrence and one patient who developed distant recurrence were all positive for STAS.

Conclusions

STAS was predictive of poor postoperative survival in patients with early‐stage adenocarcinomas treated with limited resection and was associated with surgical margin recurrence.