Indications for sublobar resection of clinical stage IA radiologic pure-solid lung adenocarcinoma

Explainable PET-Based Habitat and Peritumoral Machine Learning Model for Predicting Progression-free Survival in Clinical Stage IA Pure-Solid Non-small Cell Lung Cancer: A Two-center Study

RATIONALE AND OBJECTIVES

This study aimed to develop and validate machine learning (ML) models utilizing positron emission tomography (PET)-habitat of the tumor and its peritumoral microenvironment to predict progression-free survival (PFS) in patients with clinical stage IA pure-solid non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

234 Patients who underwent lung resection for NSCLC from two hospitals were reviewed. Radiomic features were extracted from both intratumoral, peritumoral and habitat regions on PET. Univariate and multivariate logistic regression analyses were employed to determine significant clinical variables. Subsequently, a radiomics nomogram was developed by combining the radiomics signature with these identified clinical variables. Kaplan-Meier (KM) analysis was performed to investigate the prognostic value of the nomogram. Shapley Additive Explanations (SHAP) were used to interpret the ML models.

RESULTS

The combination model which contained peritumoral 5 mm and habitat regions radiomics features, clinical variables obtained a strong well-performance, achieving area under the curve (AUC) of 0.905 (95% confidence interval (CI) 0.854-0.957) in the train set and 0.875 (95% CI 0.789-0.962) in the internal validation set. The radiomics signature was significantly associated with PFS, the model significantly discerned high and low-risk patients, and exhibited a significant benefit in the clinical use showed low-risk score given have far longer RFS than those with high-risk score (log-rank P＜0.001).

CONCLUSION

The habitat and peritumoral radiomics signatures serve as an independent biomarker for predicting PFS in patients with early-stage NSCLC, effectively stratified survival risk among patients with clinical stage IA pure-solid non-small cell lung cancer.

Segmentectomy versus lobectomy in small-sized peripheral non-small-cell lung cancer with radiologically pure-solid appearance in Japan (JCOG0802/WJOG4607L): a post-hoc supplemental analysis of a multicentre, open-label, phase 3 trial

BACKGROUND

Although segmentectomy was better than lobectomy in terms of overall survival for patients with non-small-cell lung cancer (NSCLC) with a pure-solid tumour appearance on thin-section CT in the open-label, multicentre, randomised, controlled, phase 3 JCOG0802/WJOG4607L trial, the reasons why segmentectomy was associated with better overall survival were unclear. We aimed to compare the survival, cause of death, and recurrence patterns after segmentectomy versus lobectomy in trial participants with NSCLC with a pure-solid appearance METHODS: We conducted a post-hoc supplemental analysis of the JCO0802/WJOG4607L randomised, controlled, non-inferiority trial for the patients (aged 20-85 years) with small-sized NSCLC with radiologically pure-solid appearance on thin-section CT (≤2 cm, consolidation tumour ratio 1·0). The primary aim was to compare the overall and relapse-free survival, cause of death, and recurrence patterns associated with segmentectomy and lobectomy for patients with radiologically pure-solid NSCLC to determine why the overall survival of segmentectomy was superior to that of lobectomy, even for oncologically invasive lung cancers. JCO0802/WJOG4607L is registered with the UMIN Clinical Trials Registry, UMIN000002317, and is complete.

FINDINGS

Between Aug 10, 2009, and Oct 21, 2014, 1106 patients were randomly assigned to undergo either lobectomy or segmentectomy. Of these participants, 553 (50%) had radiologically pure-solid NSCLC and were eligible for this post-hoc supplemental analysis. Of these 553 participants, 274 (50%) patients underwent lobectomy and 279 (50%) underwent segmentectomy. Median patient age was 67 years (IQR 61-73), 347 (63%) of 553 patients were male and 206 (37%) were female, and data on race and ethnicity were not collected. As of data cutoff (June 13, 2020), after a median follow-up of 7·3 years (IQR 6·0-8·5), the 5-year overall survival rate was significantly higher after segmentectomy than after lobectomy (86·1% [95% CI 81·4-89·7] in the lobectomy group, with 55 deaths vs 92·4% [88·6-95·0] in the segmentectomy group, with 38 deaths; hazard ratio (HR) 0·64 [95% CI 0·41-0·97]; log-rank test p=0·033), whereas the 5-year relapse-free survival was similar between the groups (81·7% [95% CI 76·5-85·8], with 34 events vs 82·0% [76·9-86·0], with 52 events; HR 1·01 [95% CI 0·72-1·42]; p=0·94). Deaths after a median follow-up of 7·3 years due to lung cancer occurred in 20 (7%) of 274 patients after lobectomy and 19 (7%) of 279 after segmentectomy, and deaths due to other causes occurred in 35 (13%) patients after lobectomy compared with 19 (7%) after segmentectomy (lung cancer death vs other cause of death, p=0·19). The locoregional recurrence was higher after segmentectomy (21 [8%] vs 45 [16%]; p=0·0021). In subgroup analyses, better 5-year overall survival after segmentectomy than after lobectomy was observed in the subgroup of patients aged 70 years or older (77·1% [95% CI 68·2-83·8] with lobectomy vs 85·6% [77·5-90·9] with segmentectomy; p=0·013) and in male patients (80·5% [73·7-85·7] vs 92·1% [87·0-95·2]; p=0·0085). By contrast, better 5-year relapse-free survival after lobectomy than after segmentectomy was observed in the subgroup younger than 70 years (87·4% [95% CI 81·2-91·7] with lobectomy vs 84·4% [77·9-89·1] with segmentectomy; p=0·049) and in female patients (94·2% [87·6-97·4] vs 82·2% [73·2-88·4]; p=0·047).

INTERPRETATION

This post-hoc analysis showed improved overall survival after segmentectomy in patients with pure-solid NSCLC compared with lobectomy. However, survival outcomes of segmentectomy depend on the patient's age and sex. Given the results of this exploratory analysis, further research is necessary to determine clinically relevant indications for segmentectomy in radiologically pure-solid NSCLC.

FUNDING

Japanese National Cancer Center Research and Development Fund and Practical Research for Innovative Cancer Control Fund, and a Grant-in-Aid for Scientific Research from the Ministry of Health, Labor, and Welfare of Japan.

Differential efficacy of segmentectomy and wedge resection in sublobar resection compared to lobectomy for solid-dominant stage IA lung cancer: a systematic review and meta-analysis

BACKGROUND

Currently, the impact of sublobar resection versus lobectomy on the prognosis of solid-dominant stage IA lung cancer is contradictory in different studies, which requires further exploration.

METHODS

The authors analyzed 26 studies, including one randomized controlled trial and retrospective cohort studies. Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using fixed-effects or random-effects models based on heterogeneity levels.

RESULTS

The analysis included 12 667 patients, with 3488 undergoing sublobar resections and 9179 receiving lobectomies. The overall analysis revealed no statistically significant difference in overall survival (OS) (HR=1.28, 95% CI: 0.98-1.69) between sublobar resection and lobectomy, but lobectomy was associated with better recurrence-free survival (RFS) (HR=1.39, 95% CI: 1.10-1.75). Subgroup analyses revealed that, for tumors with a diameter ≤2 cm, sublobar resection versus lobectomy showed no significant difference in OS but sublobar resection had lower RFS. For 2-3 cm tumors, both OS and RFS were significantly lower in the sublobar resection group. When consolidation-to-tumor ratio (CTR) ranged from 0.5 to <1, OS did not differ significantly, but RFS was significantly lower in sublobar resection. Lung cancers with CTR=1 showed significantly lower OS and RFS in the sublobar resection group. Segmentectomy provided similar OS and RFS compared to lobectomy, while wedge resection had a detrimental effect on patient prognosis. However, wedge resection may have provided comparable outcomes for patients aged 75 years or older.

CONCLUSION

Our findings suggest that segmentectomy and lobectomy yield similar oncological outcomes. However, compared to lobectomy, wedge resection is associated with a poorer prognosis. Nevertheless, for elderly patients, wedge resection is also a reasonable surgical option.

Advances in diagnosis and prediction for aggression of pure solid T1 lung cancer

A growing number of early-stage lung cancers presenting as malignant pulmonary nodules have been diagnosed because of the increased adoption of low-dose spiral computed tomography. But pure solid T1 lung cancer with ≤3 cm in the greatest dimension is not always at an early stage, despite its small size. This type of cancer can be highly aggressive and is associated with pathological involvement, metastasis, postoperative relapse, and even death. However, it is easily misdiagnosed or delay diagnosed in clinics and thus poses a serious threat to human health. The percentage of nodal or extrathoracic metastases has been reported to be >20% in T1 lung cancer. As such, understanding and identifying the aggressive characteristics of pure solid T1 lung cancer is crucial for prevention, diagnosis, and therapeutic strategies, and beneficial to improving the prognosis. With the widespread of lung cancer screening, these highly invasive pure solid T1 lung cancer will become the main advanced lung cancer in future. However, there is limited information regarding precision medicine on how to identify these "early-stage" aggressive lung cancers. To provide clinicians with new insights into early recognition and intervention of the highly invasive pure solid T1 lung cancer, this review summarizes its clinical characteristics, imaging, pathology, gene alterations, immune microenvironment, multi-omics, and current techniques for diagnosis and prediction.

Prognostic role of preoperative fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography with an image-based harmonization technique: A multicenter retrospective study

Objectives

Despite the prognostic impacts of preoperative fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography examination, fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography-based prognosis prediction has not been used clinically because of the disparity in data between institutions. By applying an image-based harmonized approach, we evaluated the prognostic roles of fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters in clinical stage I non-small cell lung cancer.

Methods

We retrospectively examined 495 patients with clinical stage I non-small cell lung cancer who underwent fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography examinations before pulmonary resection between 2013 and 2014 at 4 institutions. Three different harmonization techniques were applied, and an image-based harmonization, which showed the best-fit results, was used in the further analyses to evaluate the prognostic roles of fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters.

Results

Cutoff values of image-based harmonized fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters, maximum standardized uptake, metabolic tumor volume, and total lesion glycolysis were determined using receiver operating characteristic curves that distinguish pathologic high invasiveness of tumors. Among these parameters, only the maximum standardized uptake was an independent prognostic factor in recurrence-free and overall survivals in univariate and multivariate analyses. High image-based maximum standardized uptake value was associated with squamous histology or lung adenocarcinomas with higher pathologic grades. In subgroup analyses defined by ground-glass opacity status and histology or by clinical stages, the prognostic impact of image-based maximum standardized uptake value was always the highest compared with other fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters.

Conclusions

The image-based fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography harmonization was the best fit, and the image-based maximum standardized uptake was the most important prognostic marker in all patients and in subgroups defined by ground-glass opacity status and histology in surgically resected clinical stage I non-small cell lung cancers.

Segmentectomy versus lobectomy for small-sized pure solid non-small cell lung cancer

BACKGROUND

Segmentectomy has been recommended for ground glass opacity (GGO)-dominant small-sized non-small cell lung cancer (NSCLC) or those with GGO component. Pure solid NSCLC is a special sub-type and has an inferior prognosis. Whether segmentectomy could achieve comparable long-term outcomes with lobectomy for pure solid small-sized NSCLC remained controversial. This study aimed to compare the prognosis of segmentectomy and lobectomy for pure solid NSCLC.

METHODS

NSCLC patients with a pure solid nodule (≤2 cm) who received segmentectomy or lobectomy between January 2010 and June 2019 were retrospectively screened. Log-rank test, univariable, and multivariable Cox regression analyses were used for prognostic comparison. Further, the propensity score matching analysis was adopted to yield a matched cohort.

RESULTS

After screening, 344 pure solid NSCLC patients with a median follow-up time of 56 months were reserved. Among them, 98 patients underwent segmentectomy and the other 246 subjects received lobectomy. The lobectomy group had a larger tumor size, a higher rate of lymph node metastasis than the segmentectomy arm. Generally, patients with segmentectomy had a better disease-free survival (DFS) (p = 0.011) and overall survival (OS) (p = 0.028) than those with lobectomy. However, the multivariable Cox regression analysis indicated that no significant survival difference existed between segmentectomy and lobectomy after adjusting the potential confounding factors (DFS: hazard ratio [HR], 0.72; 95% confidence interval [CI], 0.30-1.77, p = 0.476; OS: HR, 0.36; 95% CI, 0.08-1.59, p = 0.178). Consistently, in the propensity score matched cohort, segmentectomy (n = 74) yielded similar DFS (p = 0.960) and OS (p = 0.320) with lobectomy (n = 74).

CONCLUSIONS

Segmentectomy could achieve comparable oncological outcomes with lobectomy for pure solid small-sized NSCLC.

Pathologically noninvasive cancer predictors and surgical procedure for peripheral lung cancer

BACKGROUND

In this retrospective study, based on recent studies reporting the superiority of sublobar resection to lobectomy for peripheral small size non-small cell lung cancer (NSCLC), we investigated the optimal pathological factors for predicting noninvasive cancer and the selection of operative procedure.

METHODS

Patients with peripheral NSCLC of ≤2 cm who underwent surgery at our hospital between January 2010 and June 2020 were included in this study. We evaluated the relationship between pathologically noninvasive cancer and predictive factors according to the area under the curve (AUC) and accuracy, and the cutoff value was set to investigate indications for sublobar resection.

RESULTS

The comparison of the AUCs revealed that the maximum standardized uptake value and consolidation to tumor (C/T) volume ratio were better predictors than the C/T ratio. Among the three factors, the C/T volume ratio showed the best accuracy. The patients were divided into two groups (low and high) using the cutoff value of the C/T volume ratio and compared according to the surgical procedure (lobectomy vs. segmentectomy). In the low-group, there was no significant difference in the prognosis. In the high-group, the 5-year recurrence-free survival rate of the patients who received lobectomy was 87.8%, while that of patients who received segmentectomy was 75.8% (p = 0.08).

CONCLUSIONS

The C/T volume ratio was the best preoperative pathologically noninvasive predictive factor. Sublobar resection should be performed with caution in cases with significant solid components on three-dimensional images.

Prognostic impact of the tumor volume doubling time in clinical T1 non-small cell lung cancer with solid radiological findings

BACKGROUND

The purpose of this study was to investigate better radiological prognostic factors in clinical T1 pure-solid non-small cell lung cancer (NSCLC).

METHODS

This study enrolled 284 patients with clinical T1 solid NSCLC who underwent anatomical lung resection. The Cox proportional hazard model was used to evaluate the prognostic impact of tumor volume doubling time (VDT) at disease-free survival (DFS) and cancer-specific survival (CSS).

RESULTS

The median VDT was 347 days. Age (hazard ratio (HR) = 1.04; 95% confidence interval (CI), 1.01-1.07) and standardized uptake value max (SUVmax) (>6.0) (HR = 2.61; 95% CI, 1.52-4.66) were identified as significantly independent worse prognostic factors for DFS in a multivariable analysis without VDT. Furthermore, a multivariable analysis without SUVmax identified age (HR = 1.06; 95% CI, 1.03-1.09), CEA (>5.0 ng/ml) (HR = 2.34; 95% CI, 1.30-4.02), tumor diameter on CT (>2.0 cm) (HR = 1.91; 95% CI, 1.18-3.13), and VDT (HR = 4.03; 95% CI, 2.41-6.93) as significantly independent worse prognostic factors for DFS.

CONCLUSIONS

The VDT value could be a useful prognostic factor in clinical T1 solid NSCLC.

Combination of mean CT value and maximum CT value as a novel predictor of lepidic predominant lesions in small lung adenocarcinoma presenting as solid nodules

Lung adenocarcinomas presenting as solid nodules are occasionally diagnosed as lepidic predominant lesions. The aim of this study was to clarify the histological structure and to identify factors predictive of lepidic predominant lesions. We retrospectively reviewed 38 patients that underwent lobectomy for small (≤ 2 cm) adenocarcinoma presenting as solid nodules. Resected tumor slides were reviewed and histological components were evaluated. Clinical and radiological data were analyzed to identify factors predictive of lepidic predominant lesions. Of 38 solid nodules, 9 (23.7%) nodules were lepidic predominant lesions. Five-year disease-free survival (DFS) rates were 100% for lepidic predominant lesions (n = 9) and 74.6% for non-lepidic predominant lesions (n = 29). Mean CT values (p = 0.039) and maximum CT values (p = 0.015) were significantly lower in lepidic predominant lesions compared with non-lepidic predominant lesions. For the prediction of lepidic predominant lesions, the sensitivity and specificity of mean CT value (cutoff, - 150 HU) were 77.8% and 82.8%, respectively, and those of maximum CT value (cutoff, 320 HU) were 77.8% and 72.4%, respectively. A combination of mean and maximum CT values (cutoffs of - 150 HU and 380 HU for mean CT value and maximum CT value, respectively) more accurately predicted lepidic predominant lesions, with a sensitivity and specificity of 77.8% and 86.2%, respectively. The prognosis of lepidic predominant lesions was excellent, even for solid nodules. The combined use of mean and maximum CT values was useful for predicting lepidic predominant lesions, and may help predict prognosis.

Quantifying invasiveness of clinical stage IA lung adenocarcinoma with computed tomography texture features

OBJECTIVES

The study objectives were to establish and validate a nomogram for pathological invasiveness prediction in clinical stage IA lung adenocarcinoma and to help identify those potentially unsuitable for sublobar resection-based computed tomography texture features.

METHOD

Patients with clinical stage IA lung adenocarcinoma who underwent surgery at Guangdong Provincial People's Hospital between January 2015 and October 2018 were retrospectively reviewed. All surgically resected nodules were pathologically classified into less-invasive and invasive cohorts. Each nodule was manually segmented, and its computerized texture features were extracted. Clinicopathological and computed tomographic texture features were compared between 2 cohorts. A nomogram for distinguishing the pathological invasiveness was established and validated.

RESULTS

Among 428 enrolled patients, 249 were diagnosed with invasive pathological subtypes. Smoking status (odds ratio, 2.906; 95% confidence interval, 1.285-6.579; P = .011), mean computed tomography attenuation value (odds ratio, 1.005, 95% confidence interval, 1.002-1.007; P < .001), and entropy (odds ratio, 8.536, 95% confidence interval, 3.478-20.951; P < .001) were identified as independent predictors for pathological invasiveness by multivariate logistics regression analysis. The nomogram showed good calibration (P = .182) with an area under the curve of 0.849 when validated with testing set data. Decision curve analysis indicated the potentially clinical usefulness of the model with respect to treat-all or treat-none scenario. Compared with intraoperative frozen-section, the nomogram performed better in pathological invasiveness diagnosis (area under the curve, 0.815 vs 0.670; P = .00095).

CONCLUSIONS

We established and validated a nomogram to compute the probability of invasiveness of clinical stage IA lung adenocarcinoma with great calibration, which may contribute to decisions related to resection extent.

Latest Clinical Evidence and Operative Strategy for Small-Sized Lung Cancers

Many thoracic surgeons revealed that consolidation tumor ratio or solid component size on thin-section computed tomography has been considered more prognostic than maximum tumor size in non-small cell lung cancer (NCSLC). According to the results, the 8th TNM classification drastically changed the staging system, i.e., clinical T category was determined based on the invasive or solid component size excluding a ground-glass opacity (GGO). However, several debates are arising over the application of radiological solid size for the clinical T staging. Meanwhile, recent several institutional reports have noticed a significantly simple fact that the presence of a GGO denotes an influence on the favorable prognosis of NSCLC. More important, radiologic pure-solid lung cancers without a GGO exhibit more malignant behaviors with regard to both the clinical and pathological aspects, and show several histologic types that have a poorer prognosis than radiologic part-solid lung cancer. In contrast, favorable prognostic impact of the presence of a GGO component was demonstrated, which was irrespective of the solid component size in cases in which the tumor showed a GGO component. Recently, this concept has been gradually noticed on a nationwide level. Obvious distinctions regarding the several baseline characteristics between the tumor with/without GGO component is a fundamental biological feature of early-stage lung cancer, which would result in a big difference in prognosis, modes of recurrence, overall behavior, and appropriate operative strategies. As a future perspective, the presence or absence of a GGO should be considered as an important parameter in the next clinical T classification.

Radiomics for Survival Risk Stratification of Clinical and Pathologic Stage IA Pure-Solid Non-Small Cell Lung Cancer

Background Radiomics-based biomarkers enable the prognostication of resected non-small cell lung cancer (NSCLC), but their effectiveness in clinical stage and pathologic stage IA pure-solid tumors requires further determination. Purpose To construct an efficient radiomics signature for survival risk stratification personalized for patients with clinical stage and pathologic stage IA pure-solid NSCLC. Materials and Methods In this retrospective study, six radiomics signatures were constructed for patients with stage IA pure-solid NSCLC who underwent resection between January 2011 and December 2013 at authors' institution and were tested in the radiogenomics data set. The radiomics features were extracted from the intratumoral two-dimensional region, three-dimensional volume, and peritumoral area using PyRadiomics. The discriminative abilities of the signatures were quantified using the area under the time-dependent receiver operating characteristic curve (AUC), and the optimal signature was selected for patient stratification. Results The study included 592 patients with stage IA pure-solid NSCLC (median age, 61 years; interquartile range, 55-66 years; 269 women) for radiomics analysis: 381 patients for training, 163 for internal validation, and 48 for external validation. The radiomics signature combining three-region features yielded the highest 3- and 5-year AUCs of 0.77 and 0.78, respectively, in the internal validation set and 0.76 and 0.75, respectively, in the external validation set. Multivariable analysis suggested that the radiomics signature remained an independent prognostic factor (hazard ratio, 6.2; 95% CI: 3.5, 11.0; P < .001) and improved the discriminative ability and clinical usefulness of conventional clinical predictors. Conclusion The radiomics signature with multiregional features helped stratify the survival risk of patients with clinical stage and pathologic stage IA pure-solid non-small cell lung cancer. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Hsu and Sohn in this issue.

Prognostic influence of a ground-glass opacity component in hypermetabolic lung adenocarcinoma

OBJECTIVES

We evaluated the oncological role of a ground-glass opacity (GGO) component in hypermetabolic lung adenocarcinoma with a high maximum standardized uptake value.

METHODS

Between 2008 and 2017, we retrospectively reviewed the data of surgically resected clinically node-negative lung adenocarcinomas with a hypermetabolic activity. Furthermore, they were classified based on the presence of GGO. The prognostic significance of a GGO in hypermetabolic tumours was evaluated using the Cox proportional-hazards model. The overall survival (OS) was estimated by the Kaplan-Meier method using a log-rank test.

RESULTS

Of the 1134 surgically resected clinically node-negative lung adenocarcinoma, 603 cases with hypermetabolic activity (maximum standardized uptake value ≥3.0 mg/dl) were evaluated. Among them, there were 120 (20%) cases in the With GGO group and 483 (80%) in the Solid group. The 5-year OS of patients with hypermetabolic lung adenocarcinoma was significantly different between the With GGO and Solid groups (83.1% vs 59.4%, P < 0.001). After stratifying by the presence of GGO, maximum standardized uptake value and maximum tumour size were independently significant prognosticators in the Solid group by multivariable analysis; however, no clinical factors were associated with survival among the With GGO group. The 5-year OS was favourable despite the solid component size among the With GGO group (T1a + T1b: 85.5%, T1c: 80.0%, T2a or more: 84.2%, P = 0.904). For the Solid group, survival diminished drastically with increasing tumour size (T1a + T1b: 68.7%, T1c: 62.8%, T2a or more: 48.0%, P < 0.001).

CONCLUSIONS

The prognosis of lung adenocarcinoma with GGO was favourable even in hypermetabolic tumours. Accordingly, the presence of GGO should be considered as an important parameter in the next clinical T classification.

Maximum standardized uptake value of the primary tumor does not improve candidate selection for sublobar resection

OBJECTIVE

This retrospective study examined whether adding the maximum standardized uptake value of a primary tumor to the consolidation-to-tumor ratio from a high-resolution computed tomography scan can improve the predictive accuracy for pathological noninvasive lung cancer and lead to better patient selection for sublobar resection.

METHODS

We included 926 patients with clinical stage IA non-small cell lung cancer. Pathological noninvasive cancer (n = 515) was defined as any case without lymphatic invasion, vascular invasion, or lymph node metastasis. The prediction accuracies of maximum standardized uptake value and consolidation-to-tumor ratio were evaluated using receiver operating characteristic curves and area under the curve.

RESULTS

For consolidation-to-tumor ratio or maximum standardized uptake value alone, the area under the curves were 0.733 (95% confidence interval, 0.708-0.758) and 0.842 (95% confidence interval, 0.816-0.866), respectively. When the consolidation-to-tumor ratio and maximum standardized uptake value were combined, the area under the curve was 0.854 (95% confidence interval, 0.829-0.876). However, to obtain a predictive specificity of 97%, sensitivity needed to be 42.5% for the consolidation-to-tumor ratio, 38.3% for the maximum standardized uptake value, and 45.0% for these 2 in combination.

CONCLUSIONS

Our results suggest that despite the high area under the curve for maximum standardized uptake value, caution is needed when using maximum standardized uptake value to select candidates for sublobar resection. We found that a low maximum standardized uptake value did not mean the tumor was a pathological noninvasive lung cancer. Therefore, using consolidation-to-tumor ratios from high-resolution computed tomography to decide whether sublobar resection is appropriate for patients with clinical stage IA non-small cell lung cancer is better than using maximum standardized uptake value when setting specificity to a conservative 97% for predicting pathological noninvasive lung cancer.

Radiomics is feasible for prediction of spread through air spaces in patients with nonsmall cell lung cancer

Tumor spread through air spaces (STAS) in non-small-cell lung cancer (NSCLC) is known to influence a poor patient outcome, even in patients presenting with early-stage disease. However, the pre-operative diagnosis of STAS remains challenging. With the progress of radiomics-based analyses several attempts have been made to predict STAS based on radiological findings. In the present study, patients with NSCLC which is located peripherally and tumors ≤ 2 cm in size on computed tomography (CT) that were potential candidates for sublobar resection were enrolled in this study. The radiologic features of the targeted tumors on thin-section CT were extracted using the PyRadiomics v3.0 software package, and a predictive model for STAS was built using the t-test and XGBoost. Thirty-five out of 226 patients had a STAS histology. The predictive model of STAS indicated an area under the receiver-operator characteristic curve (AUC) of 0.77. There was no significant difference in the overall survival (OS) for lobectomy between the predicted-STAS (+) and (−) groups (p = 0.19), but an unfavorable OS for sublobar resection was indicated in the predicted-STAS (+) group (p < 0.01). These results suggest that radiomics with machine-learning helped to develop a favorable model of STAS (+) NSCLC, which might be useful for the proper selection of candidates who should undergo sublobar resection.

Extent of mediastinal nodal dissection in stage I non-small cell lung cancer with a radiological pure-solid appearance

BACKGROUND

Radiological pure-solid lung cancer denotes a high invasive nature compared to one that is part-solid. Mediastinal lymph nodal dissection (mLND) is a standard surgical procedure for nodal management in lung cancer surgery, however, the prognostic impact of the extent of mLND in pure-solid lung cancer is still unknown.

METHODS

We reviewed 459 patients with c-stage I radiological pure-solid lung cancer that underwent pulmonary lobectomy with mLND. Pure-solid was defined as a tumor showing only a consolidation without any ground glass opacity. The extent of mLND was classified into lobe-specific (L-mLND) and systematic (S-mLND). Prognostic significance of mLND was assessed by a multivariable analysis using propensity-score matching. Survivals were calculated by Kaplan-Meier methods using log-rank test.

RESULTS

Pathological nodal metastasis was found in 127 (27.6%) patients (hilar: 52 (11.3%), mediastinal: 75 (16.3%)). L-mLND was performed in 278 (61%) patients. A multivariable analysis did not show the survival difference for the extent of mLND (p = 0.266). The 5-year overall survival (OS) was not significantly different between S-mLND and L-mLND (74.3% vs. 72.7%, p = 0.712), which was similar even in 114 propensity-score matched pairs (78.8% vs. 79.9%, p = 0.665). While S-mLND showed a trend for survival benefit compared to L-mLND provided that the tumor showed higher standardized uptake value (SUVmax) (5y-OS: 70.0% vs. 59.2%, p = 0.093).

CONCLUSIONS

Prognostic impact of L-mLND was similar to S-mLND in c-stage I radiological pure-solid lung cancers in the propensity-score matched comparison. Among them, higher SUVmax value might be a promising indicator to decide the extent of mediastinal lymphadenectomy.

Prognosis of wide wedge resection in patients with stage IA1 and IA2 lung adenocarcinoma with total tumor size including the lepidic component greater than 2 cm: a single center retrospective study

Background

Stage I lung adenocarcinoma with a lepidic component has a good prognosis after sublobar resection. The purpose of this study is to evaluate the prognosis of wide wedge resection in patients diagnosed with stage IA1 and IA2 lung adenocarcinoma (based on the eighth edition of the TNM staging system) in which the total tumor size, including the lepidic component, is more than 2 cm.

Methods

From 2010 to 2018, 180 consecutive patients were diagnosed with stage IA1 and IA2 lung adenocarcinoma with a total tumor size (including the lepidic component) of more than 2 cm, and they underwent wide wedge resection or lobectomy at a hospital in Korea. The patients were determined as stage IA1 or stage IA2, and their clinicopathological characteristics and prognosis were compared between the wedge resection group and the lobectomy group.

Results

The clinicopathological characteristics were not statistically different between the wedge resection group and the lobectomy group. There were no recurrences and cancer-related deaths during the follow-up period for patients with stage IA1 lung adenocarcinoma in the wedge resection group and the lobectomy group. However, the 5-year recurrence-free survival rates of the wedge resection group and the lobectomy group were statistically different (73.9% and 90.8%, respectively; P=0.031) in stage IA2 lung adenocarcinoma. In a multivariate analysis of risk factors for recurrence, wedge resection [hazard ratio (HR) =15.883; P=0.026] and lymphovascular invasion (HR =13.854; P=0.023) were significant risk factors for recurrence in patients with stage IA2 lung adenocarcinoma.

Conclusions

In the cases of lung adenocarcinoma with a total tumor size (including the lepidic component) of more than 2 cm, a good prognosis can be expected with wide wedge resection in stage IA1, but not an appropriate surgical choice for the cases in stage IA2.

Impact of treatment modality on long-term survival of stage IA small-cell lung cancer patients: a cohort study of the U.S. SEER database

Background

The optimal treatment modality for patients with stage IA (T1N0M0) small-cell lung cancer (SCLC) is still unclear.

Methods

Patients who received surgical resection or chemo-radiotherapy (CRT) between January 2004 and December 2014 were identified from The Surveillance, Epidemiology and End Results (SEER) database. Surgical resection included lobectomy, wedge resection, segmentectomy with lymphadenectomy [examined lymph node (ELN) ≥1]. Propensity score match analysis was utilized to balance the baseline characteristics.

Results

A total of 686 stage IA SCLC cases were included: 337 patients underwent surgery and 349 patients were treated by CRT alone. Surgery achieved a better outcome than CRT alone, with an adjusted hazard ratio (HR) of 0.495. Patients who underwent lobectomy demonstrated a longer overall survival (OS), compared to those who received sublobectomy (crude cohort, median OS, 69 vs. 38 months; match cohort, median OS, 67 vs. 38 months). Patients with ELN >7 presented with longer OS than those with ELN ≤7 (crude cohort, median OS, 91 vs. 49 months; matched cohort, median OS, 91 vs. 54 months). The additional efficacy of chemotherapy or radiotherapy in patients receiving lobectomy was observed. The best prognosis was achieved in the lobectomy plus CRT cohort, with a 5-year survival rate of 73.5%.

Conclusions

The prolonged survival associated with lobectomy and chemotherapy or radiotherapy presents a viable treatment option in the management of patients with stage IA SCLC.

Oncologic outcomes of lobectomy vs. segmentectomy in non-small cell lung cancer with clinical T1N0M0 stage: a literature review and meta-analysis

Background

Lobectomy has long been regarded as the standard treatment for operable non-small cell lung cancer (NSCLC). Recent studies suggested that segmentectomy could achieve a good prognosis for early-stage NSCLC and might be an alternative to lobectomy in this cohort. Until now, on the issue of comparison between lobectomy and segmentectomy, there remains no published randomized controlled trial (RCT), and all existing evidence is low. Recently, a categorization of lower-level evidence has been proposed, namely, the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system. The aim of this meta-analysis is to compare the oncologic outcome between lobectomy and segmentectomy in NSCLC with the clinical T1N0M0 stage according to the GRADE system.

Methods

PubMed, the PMC database, EMBASE, Web of Science, and the Cochrane library were searched prior to May 2019 to identify studies that compared the prognosis between lobectomy and segmentectomy for clinical T1N0M0 NSCLC. The evidence level of the included studies was assessed according to the GRADE system, including level IIA, probably not confounded nonrandomized comparison; level IIB, possibly confounded nonrandomized comparison; and level IIC, probably confounded nonrandomized comparison. The predefined outcomes included overall survival (OS) and disease-free survival (DFS). Univariable and multivariable hazard ratios (HRs) with 95% confidence intervals (95% CI) were pooled using a random-effects model.

Results

Twelve nonrandomized studies involving 8,072 participants were included. Of these studies, two were classified as IIA level (16.7%), six as IIB level (50.0%), and four as IIC level (33.3%). When crude HRs were included, compared with lobectomy, segmentectomy was associated with shorter OS but comparable DFS in the entire cohort (OS, pooled HR =1.45, 95% CI, 1.23 to 1.67; DFS, pooled HR =1.03, 95% CI, 0.65 to 1.82) and in patients with nodules ≤2 cm (OS, pooled HR =1.55, 95% CI, 1.33 to 1.80; DFS, pooled HR =0.98, 95% CI, 0.55 to 1.77). When adjusted HRs were included, the impact of segmentectomy on OS and DFS was comparable to that of lobectomy in the entire cohort (OS, pooled HR =1.39, 95% CI, 0.92 to 2.10; DFS, pooled HR =0.83, 95% CI, 0.66 to 1.03) and in patients with nodules ≤2 cm (OS, pooled HR =1.61, 95% CI, 0.87 to 3.00; DFS, pooled HR =0.90, 95% CI, 0.63 to 1.27).

Conclusions

Based on our results, although shorter OS is observed in patients received segmentectomy, it is necessary to wait for more results from RCT to draw a valid conclusion.

Oncologic Outcomes of Surgery Versus SBRT for Non-Small-Cell Lung Carcinoma: A Systematic Review and Meta-analysis

BACKGROUND

The optimal treatment of stage I non-small-cell lung carcinoma is subject to debate. The aim of this study was to compare overall survival and oncologic outcomes of lobar resection (LR), sublobar resection (SR), and stereotactic body radiotherapy (SBRT).

METHODS

A systematic review and meta-analysis of oncologic outcomes of propensity matched comparative and noncomparative cohort studies was performed. Outcomes of interest were overall survival and disease-free survival. The inverse variance method and the random-effects method for meta-analysis were utilized to assess the pooled estimates.

RESULTS

A total of 100 studies with patients treated for clinical stage I non-small-cell lung carcinoma were included. Long-term overall and disease-free survival after LR was superior over SBRT in all comparisons, and for most comparisons, SR was superior to SBRT. Noncomparative studies showed superior long-term overall and disease-free survival for both LR and SR over SBRT. Although the papers were heterogeneous and of low quality, results remained essentially the same throughout a large number of stratifications and sensitivity analyses.

CONCLUSION

Results of this systematic review and meta-analysis showed that LR has superior outcomes compared to SBRT for cI non-small-cell lung carcinoma. New trials are underway evaluating long-term results of SBRT in potentially operable patients.

Nonintubated thoracoscopic surgery for early-stage non-small cell lung cancer

OBJECTIVES

Recent advances in the management of early-stage non-small cell lung cancer have focused on less invasive anesthetic and surgical techniques. Video-assisted thoracoscopic surgery without tracheal intubation is an evolving technique to provide a safe alternative with less short-term complication and faster postoperative recovery. The purpose of this review was to explore the latest developments and future prospects of nonintubated thoracoscopic surgery for early lung cancer.

METHODS

We examined various techniques and surgical procedures as well as the outcomes and benefits.

RESULTS

The results indicated a new era of video-assisted thoracoscopic surgery in which there is reduced procedure-related injury and enhanced postoperative recovery for lung cancer.

CONCLUSIONS

Nonintubated thoracoscopic surgery is a safe and feasible minimally invasive alternative surgery for early non-small cell lung cancer. Faster recovery and less short-term complication are potential benefits of this approach.

Use of Autofluorescence to Intraoperatively Diagnose Visceral Pleural Invasion From Frozen Sections in Patients With Lung Adenocarcinoma 2 cm or Less

OBJECTIVES

We prospectively investigate the accuracy of frozen sections for diagnosing visceral pleural invasion (VPI) by autofluorescence and evaluated its usefulness in sublobar resection.

METHODS

We included patients with lung adenocarcinoma 2 cm or less to evaluate the diagnostic performance of autofluorescence for VPI in frozen sections via a fluorescence microscope. Furthermore, the impact of VPI on patients treated with sublobar resection was assessed in another cohort.

RESULTS

A total of 112 patients were enrolled. The accuracy, sensitivity, and specificity of autofluorescence for VPI diagnosis was 95.5%, 86.8%, and 100%, respectively. Sublobar resection was an independent risk factor for recurrence in patients with lung adenocarcinomas 2 cm or less with VPI positivity (hazard ratio, 3.30; P = .023), whereas it was not in those with VPI negativity.

CONCLUSIONS

Using autofluorescence in frozen sections appears to be an accurate method for diagnosing VPI, which is helpful for surgical decision making.

The probability of nodal metastasis in novel T-factor: the applicability of sublobar resection

Background

Recently sublobar resection is often indicated for small-sized peripheral lung cancer according to size or the consolidation/tumor ratio on CT; however, the T-factor classification drastically changed in the 8^th version. We investigated the relationship between a novel clinical T-factor classification, which includes other clinical information and the pathologic N-factor, to evaluate the applicability of the novel T-factor classification to sublobar resection.

Methods

From January 2013 to October 2017, 545 patients with cTis or cT1 lung cancer underwent surgery. Patients with non-peripheral type, induction treatment, cN≥1, cM1, and those without nodal dissection, preoperative evaluation by thin-sliced CT or FDG-PET were excluded. Finally, 325 patients were eligible for inclusion. All clinical parameters were prospectively collected and retrospectively analyzed. The 8^th edition of TNM classification was utilized.

Results

Nodal metastasis was detected in 38 (11.7%) patients. Among cTis/1mi/1a/1b/1c patients (n=10/11/51/146/107), pN1 and pN2 were observed in 0/0/2/9/10 and 0/0/1/8/8, respectively. cT1b/c patients showed a significantly higher rate of nodal metastasis (P=0.024). Among 253 cT1b/c patients, solid-type tumors (n=177) were more frequently associated with nodal metastasis. A ROC curve analysis revealed that SUVmax 1.9 was the cutoff value (AUC=0.827) for the presence of nodal metastasis. Using the 2 parameters of solid-type or SUVmax ≥1.9, we could successfully exclude patients with nodal metastasis, for whom sublobar resection is not indicated.

Conclusions

In terms of nodal metastasis, sublobar resection can be applicable for all cTis/1mi tumors; patients with cT1a/b/c tumors with mixed GGO and low SUVmax are candidates for sublobar resection.

New revisions and current issues in the eighth edition of the TNM classification for non-small cell lung cancer

In the eighth edition of the TNM classification of lung cancer, the prognostic impact of tumor size is emphasized as a descriptor of all T categories. Especially in lung cancer where tumor size is 5 cm or less, the 1-cm cutoff point significantly differentiated the survival outcome. In addition, the new staging categories were assigned, namely, Tis (adenocarcinoma in situ) and T1mi (minimally invasive adenocarcinoma). Furthermore, the measurement of a radiological solid component size excluding the ground glass opacity component or pathological invasive size without a lepidic component was proposed for deciding the cT/pT categories for lung adenocarcinoma. The N descriptors were kept the same as in the eventh edition on the whole, however, quantification of nodal disease had a prognostic impact based on the number of nodal stations involved in the eighth edition, i.e. N1a as a single N1 station, N1b as a multiple N1 station, N2a1 as a single N2 station without N1 (skip metastasis), N2a2 as a single N2 station with N1 disease, and N2b as a multiple N2 station. In the M descriptors, subclassification was performed based on the location or numbers of distantly metastatic lesions, i.e. M1a as any intrathoracic metastases, M1b as a single distant metastatic lesion in one organ, and M1c as multiple distant metastases in either a single organ or multiple organs. Survival analysis of the eighth edition of the TNM classification clearly separated the distinct groups, however, unsolved issues still remain that should be discussed and further revised for the forthcoming TNM staging system.

Prognostic impact of preoperative comorbidities in geriatric patients with early-stage lung cancer: Significance of sublobar resection as a compromise procedure

OBJECTIVES

In high-risk operable geriatric patients undergoing palliative sublobar resection (SR), noncancerous comorbidities may contribute to unfavorable outcomes. The purpose of this retrospective study was to evaluate the perioperative safety and long-term survival of palliative SR in this patient population.

MATERIALS AND METHODS

We reviewed 232 patients (141 male, 91 female) aged ≥75 years who underwent surgical resection of clinical stage I lung cancer from 2006 to 2014. The patients were divided into two groups, lobectomy and SR, and preoperative comprehensive comorbidities were assessed using the Adult Comorbidity Evaluation 27 (ACE-27) and compared between the two groups. The operative safety was compared using the Clavien-Dindo classification. Survival rates were calculated with a Kaplan-Meier model under propensity score matching, and prognostic factors were analyzed using a Cox proportional hazard model.

RESULTS

Lobectomy was performed in 156 patients and SR in 76 (segmentectomy, n = 50; wedge resection, n = 26). Age (p = 0.0137), tumor size on computed tomography (p < 0.0001), central tumor location (p = 0.0008), and high ACE-27 scores (p = 0.0202) were significantly associated with selection of SR. No mortality occurred, and the incidence of Grade 3b or greater postoperative complications in lobectomy and SR was 5.1% and 5.3%, respectively. According to the analysis of propensity score-matched patients (n = 57, tumor size = 23 mm, and consolidation/tumor ratio = 83%), the 5-year survival rate in lobectomy and SR was 81.1% and 73.5%, respectively (p = 0.4374). The ACE-27 score was a more significant prognostic factor than the type of surgical procedure, as well as consolidation/tumor ratio and nodal metastatic status.

CONCLUSIONS

The severity of preoperative comorbidities is a significant prognostic factor, and SR as a compromise surgical procedure may provide promising short- and long-term outcomes in selected geriatric patients with clinical stage I lung cancer.

Differences of tumor microenvironment between stage I lepidic-positive and lepidic-negative lung adenocarcinomas

OBJECTIVE

Lepidic growth is a noninvasive component of lung adenocarcinoma. Many adenocarcinoma cases contain coexistent lepidic and nonlepidic (invasive) components (lepidic-growth positive [Lep+] adenocarcinoma); however, some cases comprise only nonlepidic components (lepidic-growth negative [Lep-] adenocarcinoma). The aim of this study was to investigate the biological differences between the invasive components of Lep+ and Lep- adenocarcinoma.

METHODS

We investigated the clinicopathologic characteristics of 232 adenocarcinomas (116 size-matched tumor pairs from Lep+ and Lep- adenocarcinomas). We then evaluated the cancer cell-specific expression levels of cancer stem cell, hypoxia, and invasion molecules in these lesions. The number of tumor-promoting stromal cells, including podoplanin-positive cancer-associated fibroblasts and CD204-positive tumor-associated macrophages, was also analyzed.

RESULTS

Among cases with size-matched invasive components, significant differences were shown in total tumor size and predominant subtype in invasive component between Lep+ and Lep- adenocarcinomas. The expression levels of hypoxia-related molecules were significantly lower in Lep+ adenocarcinomas (glucose transporter 1: 0 vs 10, P < .01; carbonic anhydrase IX: 0 vs 0 [mean, 4.7 vs 14.1], P = .01). The number of podoplanin-positive cancer-associated fibroblasts and CD204-positive tumor-associated macrophages was significantly lower in Lep+ adenocarcinomas (podoplanin-positive cancer-associated fibroblasts: 0 vs 0 [mean: 1.6 vs 11.6], P < .01; CD204-positive tumor-associated macrophages: 8.7 vs 24.7, P < .01).

CONCLUSIONS

Our results indicated that lower cancer cell-specific expression levels of hypoxia markers and a smaller number of tumor-promoting stromal cells in invasive component were characteristic features of Lep+ adenocarcinomas.

Surgical treatment for early stage non-small cell lung cancer

Surgery is the standard of care for early stage non-small cell lung cancer. There is significant debate about the type of operation most effective for lung cancer. Minimally invasive techniques like video-assisted (VATS) and robot-assisted thoracoscopic surgery (RATS) have been shown to reduce postoperative complications and shorten hospitalization. However, there remains skepticism about their oncologic effectiveness when compared to an open approach, though recent literature suggests no differences in upstaging or survival between VATS and thoracotomy. The extent of resection for early lung cancer also remains a matter of debate. Lobectomy remains the preferred operation and is associated with better survival and lower locoregional recurrence, but there is increased interest in the role of sublobar resections. Sublobar resections have similar mortality to lobar resections in small ground glass-predominant tumors. We examine the literature surrounding these controversies in this review.

Clinicoradiographic Predictors of Aggressive Biology in Lung Cancer With Ground Glass Components

BACKGROUND

Ground glass opacities pose diagnostic challenges, and even after malignancy is confirmed, prognosis is often unclear. We sought to identify clinicoradiographic features that could predict aggressive tumor biology in lung adenocarcinoma with associated ground glass components.

METHODS

A retrospective review of patients with resected lung adenocarcinoma from 2008 to 2013 was performed. Detailed radiographic features were reviewed by two radiologists. Logistic regression was used to identify risks of poor differentiation or a composite outcome of nodal metastases and lymphovascular invasion.

RESULTS

In all, 79 patients met criteria for analysis. Larger tumor size (p = 0.04), increasing solid component (p = 0.01), pleural tags (p = 0.03), spiculation (p = 0.01), lobulation (p < 0.05), history of coronary artery disease (p = 0.04), and increasing number of pack-years smoking (p < 0.05) were associated with poorly differentiated tumors. However, after adjustment for size of the solid component, the associations between pleural tags, spiculation, and lobulation with poorly differentiated tumors were negated, whereas number of pack-years and history of coronary artery disease remained statistically significant (p = 0.01 and p = 0.03, respectively). There were no identified clinical or radiographic features associated with lymphovascular invasion/nodal metastasis.

CONCLUSIONS

Several radiographic features were associated with aggressive tumor biology, a well-known finding. However, we found that none of these radiographic features remained relevant after we adjusted for the size of the solid component, indicating that radiographic features are not as important as previously believed. Further research will be required to identify reliable markers associated with favorable tumor biology. These studies will ultimately be critical in informing prognosis or guiding extent of resection.

Prognostic impact of a ground glass opacity component in the clinical T classification of non-small cell lung cancer

OBJECTIVE

To determine whether solid component size and the presence of a ground glass opacity (GGO) component are independently associated with survival outcomes in patients with early-stage non-small cell lung cancer (NSCLC) using the eighth edition Lung Cancer Stage Classification.

METHODS

We retrospectively evaluated 1029 surgically resected early-stage NSCLCs. T categories were assigned based on solid component size using the eighth classification. All tumors were classified into 1 of 2 groups: the GGO group or the solid group. We evaluated the prognostic impact of several clinicopathological variables in clinical T classification using a Cox proportional hazard model.

RESULTS

On multivariable analysis, the presence of a GGO component (hazard ratio [HR], 0.314; 95% confidence interval [CI], 0.181-0.529: P < .001) and solid component size (HR, 1.021; 95% CI, 1.006-1.036; P = .006) were identified as independently significant prognostic factors of overall survival. However, after accounting for the presence of a GGO component, neither maximum tumor size nor solid component size added to the prediction of long-term survival. Moreover, tumor size significantly affected survival outcome only in the solid group (HR, 1.020; 95% CI, 1.006-1.034; P = .004). Survival was excellent at ≥90% despite the revised T categories, provided that the tumor had a ground glass appearance. Meanwhile, tumor size significantly affected survival only in the solid group (P < .001).

CONCLUSIONS

The presence of a GGO component is a significant prognostic factor in early-stage NSCLC. External validation is required to assess whether it should be adopted as a novel factor in clinical T staging.