Risk factors for recurrence after sublobar resection in patients with small (2 cm or less) non-small cell lung cancer presenting as a solid-predominant tumor on chest computed tomography

Clinicopathological and computed tomography features associated with recurrence-free survival of patients with small-sized peripheral invasive lung adenocarcinoma after sublobectomy

Background

Sublobar resection is gradually becoming a standard treatment for small-sized (≤2 cm) peripheral non-small cell lung cancer (NSCLC), with lung adenocarcinoma (LADC) being the most frequent histologic subtype. However, the prognostic predictors for preoperatively determining whether sublobectomy is feasible for patients with early LADC have not yet been well identified. Therefore, this study aimed to investigate the clinicopathological and computed tomography (CT) features associated with the recurrence-free survival (RFS) of patients with small-sized invasive LADC (SILADC) after sublobar resection.

Methods

This retrospective cohort study analyzed 107 patients with SILADC who underwent preoperative chest CT scan and sublobar resection from December 2012 to March 2019. The Kaplan-Meier survival was used to analyze the relationship between clinicopathological characteristics, preoperative chest CT findings, and RFS. The Cox proportional hazards regression was used to identify independent prognostic factors of poor RFS.

Results

For clinicopathological characteristics, RFS was shorter in patients aged ≥70 years, smokers, and those with micropapillary/solid-predominant adenocarcinomas (all P values <0.05). For preoperative CT features, RFS was shorter in patients with tumor size ≥1.4 cm, solid component size ≥1.1 cm, proportion of solid component ≥72%, solid density, spiculation, vascular convergence sign, peripheral fibrosis, and type II pleural tag (all P values <0.05). Multivariate analysis showed proportion of solid component ≥72% [hazard ratio (HR): 5.920; P=0.006; 95% confidence interval (CI): 1.686-20.794], spiculation (HR: 5.026; P=0.001; 95% CI: 2.008-12.581), and type II pleural tag (HR: 4.638; P=0.002; 95% CI: 1.773-12.136) were independent risk factors for poor prognosis in patients with SILADC after sub-lobectomy.

Conclusions

Clinicopathological and CT characteristics are helpful for predicting the RFS of patients with SILADC after sublobar resection and can be used as an auxiliary tool for thoracic surgeons to choose the best surgical mode.

Importance of CT image normalization in radiomics analysis: prediction of 3-year recurrence-free survival in non-small cell lung cancer

OBJECTIVES

To analyze whether CT image normalization can improve 3-year recurrence-free survival (RFS) prediction performance in patients with non-small cell lung cancer (NSCLC) relative to the use of unnormalized CT images.

METHODS

A total of 106 patients with NSCLC were included in the training set. For each patient, 851 radiomic features were extracted from the normalized and the unnormalized CT images, respectively. After the feature selection, random forest models were constructed with selected radiomic features and clinical features. The models were then externally validated in the test set consisting of 79 patients with NSCLC.

RESULTS

The model using normalized CT images yielded better performance than the model using unnormalized CT images (with an area under the receiver operating characteristic curve of 0.802 vs 0.702, p = 0.01), with the model performing especially well among patients with adenocarcinoma (with an area under the receiver operating characteristic curve of 0.880 vs 0.720, p < 0.01).

CONCLUSIONS

CT image normalization may improve prediction performance among patients with NSCLC, especially for patients with adenocarcinoma.

KEY POINTS

• After CT image normalization, more radiomic features were able to be identified. • Prognostic performance in patients was improved significantly after CT image normalization compared with before the CT image normalization. • The improvement in prognostic performance following CT image normalization was superior in patients with adenocarcinoma.

Sublobar Resection in Stage IA Non-Small Cell Lung Cancer: Role of Preoperative CT Features in Predicting Pathologic Lymphovascular Invasion and Postoperative Recurrence

BACKGROUND. Prognostic factors on preoperative CT in stage IA non-small cell lung cancer (NSCLC) may help select patients for sublobar resection or lobectomy. OBJECTIVE. The purpose of this study was to identify CT features predictive of pathologic lymphovascular invasion (LVI) in stage IA NSCLC and to evaluate the features' prognostic value in patients who undergo sublobar resection. METHODS. This retrospective study included 904 patients (mean age, 62.0 years; 453 men, 451 women) who underwent lobectomy (n = 574) or sublobar resection (n = 330) for stage IA NSCLC. Two thoracic radiologists independently evaluated findings on pre-operative chest CT and then resolved discrepancies. Recurrences were identified from medical record review. Multivariable logistic regression was used to identify independent predictors of pathologic LVI. Multivariable Cox proportional hazards models were used to identify prognostic features. Interreader agreement was assessed. RESULTS. Pathologic LVI was present in 10.2% (92/904) of patients. It was present only in solid-dominant part-solid nodules (PSNs) and solid nodules and only in nodules with a solid portion diameter over 10 mm. Among solid-dominant PSNs and solid nodules with a solid portion diameter over 10 mm, independent (p < .05) predictors of pathologic LVI were peritumoral interstitial thickening (odds ratio [OR], 13.22) and pleural contact (defined as pleural contact measuring over one-quarter of the circumference of the nodule's solid portion) (OR, 2.45). Also among such nodules, peritumoral interstitial thickening achieved 80.4% sensitivity, 76.7% specificity, and 77.4% accuracy; pleural contact achieved 35.9% sensitivity, 82.5% specificity, and 74.3% accuracy; and presence of either feature achieved 90.2% sensitivity, 64.3% specificity, and 68.9% accuracy for predicting pathologic LVI. In patients undergoing sublobar resection, after adjusting for T category and operative type, recurrence-free survival (RFS) was independently (p < .05) predicted by solid-dominant PSN or solid nodule with a solid portion diameter over 10 mm also showing peritumoral interstitial thickening (hazard ratio [HR], 5.37) or also showing either peritumoral interstitial thickening or pleural contact (HR, 6.05). The interreader agreement kappa values were 0.67 for peritumoral interstitial thickening and 0.77 for pleural contact. CONCLUSION. Pathologic LVI occurred only in solid-dominant PSNs and solid nodules with solid portion over 10 mm. Among such nodules, peritumoral interstitial thickening and pleural contact independently predicted pathologic LVI and RFS. CLINICAL IMPACT. CT features may help select patients with stage IA NSCLC for sublobar resection rather than more extensive surgery.

Validation of completion lobectomy after wedge resection for ≤20 mm non-small cell lung cancer

Background

Completion lobectomy after wedge resection is occasionally performed when final histopathology shows an unexpected primary lung cancer even though the primary lesion has already been resected. The objective of this study was to assess the necessity of completion lobectomy after wedge resection for ≤20 mm non-small cell lung cancer (NSCLC).

Methods

Between 2006 and 2016, a total of 112 patients with NSCLC underwent wedge resection in our department. After exclusions, 40 patients were analyzed. Of these, 17 patients underwent completion lobectomy and 23 patients underwent wedge resection alone. Age, sex, tumor size, histology, other malignant diseases and final surgical procedure were used as prognostic variables. Survival analyses were confirmed using the Kaplan-Meier method and log-rank test.

Results

Median follow-up was 70.4 months. No significant difference in 5-year overall survival (OS) and relapse-free survival (RFS) were seen in patients who underwent wedge resection alone compared to the completion lobectomy group (OS: 72.6% vs. 62.5%, P=0.34; RFS: 64.2% vs. 50.0%, P=0.35). Multivariate analysis identified age (>65 years old) and male sex as independent prognostic factors for OS and RFS.

Conclusions

Completion lobectomy after wedge resection did not impact OS or RFS compared with wedge resection alone in patients with ≤20 mm NSCLC. These findings suggested that selected patients may not require resection of the remaining lobe or lymph node dissection after initial wedge resection.

Preoperative consolidation-to-tumor ratio is effective in the prediction of lymph node metastasis in patients with pulmonary ground-glass component nodules

BACKGROUND

Preoperative positron emission tomography/computed tomography (PET/CT) is recommended as a guideline for staging of lung cancer. However, for patients with pulmonary ground-glass opacity (GGO) nodules who are supposed to have a relatively low risk of incidence of lymphatic metastasis, it remains uncertain whether PET/CT is more effective than consolidation-to-tumor ratio (CTR) in the prediction of regional lymphatic metastasis.

METHODS

The data on patients who underwent surgery for lung cancer from 2011 to 2016 were collected retrospectively, which included CTR, results of PET/CT, and pathological characteristics. The patients who had undergone preoperative PET/CT were identified to find the risk factors for lymphatic metastasis. A receiver operating characteristic (ROC) curve and multiple logistic regression was utilized to clarify the predictive value of CTR and main tumor maximal standardized uptake value (SUVmax).

RESULTS

Among 217 patients who had PET/CT before lobectomy, chest computed tomography revealed that 75 patients had CTR greater than 62%. The patients with lymphatic metastasis were shown to have higher CTR and higher main tumor SUVmax. Multiple logistic regression showed that younger age (<60 years), higher main tumor SUVmax on PET/CT, and greater CTR were independent predictive factors for lymphatic metastasis. The area under the ROC curve was comparable, 0.817 for CTR, and 0.816 for main tumor SUVmax.

CONCLUSIONS

The present study revealed that CTR was not inferior to main tumor SUVmax considering the predictive power for lymphatic metastasis preoperatively in lung cancer patients with a GGO component. PET/CT might not be necessary preoperatively in selected patients.

The Effect of Resection Margin Distance and Invasive Component Size on Recurrence After Sublobar Resection in Patients With Small (≤2 Cm) Lung Adenocarcinoma

BACKGROUND

When performing sublobar resection for lung cancer, the margin distance should exceed the tumor size. However, instead of total tumor size, the 8th edition TNM staging system has adopted the size of invasive component for the T stage. The aim of this study was to determine whether the prognosis was satisfactory when the resection margin distance was greater than the invasive component size instead of the total tumor size.

METHODS

From 2008 to 2017, 193 consecutive patients were diagnosed with lung adenocarcinoma (invasive component size ≤2 cm) and underwent sublobar resection. We analyzed risk factors for recurrence using clinicopathological factors including margin/invasive component ratio (resection margin distance/invasive component size).

RESULTS

Mean tumor size was 1.4 (±0.5) cm and the mean invasive component size was 0.8 cm (±0.5). In the multivariate analysis, neither resection margin distance (cm) nor margin/tumor ratio (resection margin distance/tumor size) was significant risk factors for recurrence. On the other hand, the margin/invasive component ratio (hazard ratio =0.035, p = 0.043) and the SUVmax (hazard ratio =1.993, p = 0.033) were significant risk factors for recurrence.

CONCLUSIONS

When sublobar resection is performed for small (invasive component size ≤2 cm) adenocarcinomas of the lung, the resection margin distance should be larger than the invasive component size. Sublobar resection is not an appropriate treatment for lung adenocarcinoma with high SUVmax.

Solid component ratio influences prognosis of GGO-featured IA stage invasive lung adenocarcinoma

Background

The computed tomography (CT) characteristic of ground glass opacity (GGO) were shown to be associated with clinical significance in lung adenocarcinoma. We evaluated the prognostic value of the solid component ratio of GGO IA invasive lung adenocarcinoma.

Methods

We retrospectively analyzed the records of GGO IA patients who received surgical resection from April 2012 to December 2015. The solid component ratio was calculated based on thin-slice CT scans. Baseline features were compared stratified by the ratio. Cox proportional hazard models and survival analyses were adopted to explore potential prognostic value regarding overall survival (OS) and disease-free survival (DFS).

Results

Four hundred fifteen patients were included. The higher ratio was significantly associated with larger tumor diameter, pathological subtypes and choice of surgical type. There was a significantly worse DFS with a > 50% ratio. The subgroups of 0% and ≤ 50% ratio showed close survival curves of DFS. Similar trends were observed in OS. Multivariate analyses revealed that the ratio was a significant predictor for DFS, but not for OS. No significant prognostic difference was observed between lobectomy and limited resections.

Conclusion

A higher solid component ratio may help to predict a significantly worse prognosis of GGO IA lung adenocarcinoma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40644-020-00363-6.

Lymphadenectomy is Unnecessary for Pure Ground-Glass Opacity Pulmonary Nodules

BACKGROUND

Lobectomy plus lymph node dissection is the standard treatment of early-stage lung cancer, but the low lymph node metastasis rate with ground-glass opacity (GGO) makes surgeons not perform lymphadenectomy. This study aimed to re-evaluate the lymph node metastasis rate of GGO to help make a clinical judgment.

METHODS

We performed this retrospective study to enroll patients who received lung cancer surgery from 2011 to 2016. Patient characteristics collected included tumor size, solid part size and lymph node metastasis rate. These patients were categorized into pure GGO and part solid GGO groups to undergo analysis.

RESULTS

Lymph node metastasis rates were 0%, 3.8% and 6.9% in order of the pure GGO group, the GGO predominant group and the solid predominant group. In the lobectomy patients, the solid predominant group still showed to have the highest lymph node metastasis rate and recurrence rate (8.3% and 10.1%).

CONCLUSION

It is unnecessary to perform lymphadenectomy for patients with pure GGO in view of the 0% lymph node metastasis rate. The higher lymph node metastasis rate in the patients with the solid predominant group, 6.9%, suggested that surgeons should choose a rational lymphadenectomy method according to their GGO property and clinical judgment.

Preoperative Watchful-Waiting Time and Surgical Outcome of Patients with Non-small Cell Lung Cancer Found by Chest Low-Dose CT Screening

BACKGROUNDS

Chest low-dose CT screening (LDCTS) has been finding unprecedented numbers of peripheral non-small cell lung cancers (NSCLC) at an early stage and increased the number of patients with surgical indication. It is important to explore the influence of preoperative watchful-waiting time (WWT) on surgical outcomes. Objective is to clarify relationship between WWT and surgical outcomes of LDCTS-finding NSCLC from the view point of treatment delay.

METHODS

Total 283 cases of NSCLC, found by LDCTS and consecutively resected, were surveyed for preoperative WWT and surgical outcomes. Validity of the present guideline for management of pulmonary nodules detected by LDCTS was verified whether WWT before surgery was suitable for eradication of NSCLC.

RESULTS

The median value of WWT was 4.0 months in total, and the distribution of WWT exhibited long-tail-type pattern. That was 5.0 months in the group of pure ground-glass nodule (pGGN), 4.0 months in the group of part-solid nodule (PSN), and 1.7 months in the group of solid nodule (SON). During long-term postoperative observation time (median 79 months), 10-year progression-free survival rates were 100% in pGGN, 96% in PSN, and 72% in SON (P < .0001). They decreased significantly depending on enlargement of size: 91% or higher in size of 2 cm or smaller, and 71% or lower in size of larger than 2 cm (P < .0001).

CONCLUSIONS

Limited to LDCTS-finding nodules, surgical outcome will depend mainly on some malignant potential of NSCLC per se, rather than on duration of WWT or treatment delay.

Risk Factors of Recurrence in Patients With Clinical Stage IA Adenocarcinoma Presented as Ground-Glass Nodule

BACKGROUND

In this study we aimed to identify the risk factors of recurrence in patients with clinical stage IA adenocarcinoma presented as ground glass nodule (GGN) on computed tomography scans.

PATIENTS AND METHODS

The study included 245 patients with clinical stage IA adenocarcinoma presented as GGN who underwent surgery during 2010 to 2013. All patients were divided into 2 subgroups on the basis of consolidation diameter to tumor diameter (C/T) ratio on lung window: (1) ground-glass opacity (GGO)-dominant subgroup (C/T ≤ 0.5; n = 179); (2) solid-dominant subgroup (C/T > 0.5; n = 66). Recurrence-free survival (RFS) was analyzed to identify independent risk factors of recurrence using the Kaplan-Meier approach and multivariable Cox models.

RESULTS

Patients in the GGO-dominant subgroup had a better prognosis than those in the solid-dominant subgroup (5-year RFS: 98% vs. 87%; P < .001). Multivariate analysis confirmed that C/T ratio was an independent risk factor for RFS in patients with clinical stage IA adenocarcinoma presented as GGN (hazard ratio [HR], 9.47; 95% confidence interval [CI], 1.75-51.1; P = .009). In the analysis of the solid-dominant group, multivariate analysis showed that limited resection was an independent risk factor of recurrence in this subgroup (HR, 6.86; 95% CI, 1.50-31.42; P = .013). Regarding the GGO-dominant subgroup, surgical type was not a risk factor of recurrence.

CONCLUSION

Patients with clinical stage IA solid-dominant adenocarcinoma (C/T ratio > 0.5) had a higher rate of recurrence after limited resection than lobectomy. Thus, limited resection should be performed cautiously in these patients (C/T ratio > 0.5).

Prognosis After Sublobar Resection of Small-sized Non-small Cell Lung Cancer with Visceral Pleural or Lymphovascular Invasion

BACKGROUND

Although standard surgical treatment of stage I non-small cell lung cancer (NSCLC) is lobectomy, sublobar resection may be elected for small-sized (≤2 cm) peripheral tumors. Our aim was examine the need for completion lobectomy in the event of confirmed pleural or lymphovascular invasion after sublobar resection of NSCLC.

METHODS

A total of 271 consecutive patients undergoing curative resection of stage I NSCLC ≤2 cm were reviewed retrospectively, analyzing clinicopathologic findings and survival times of those with invasion-positive (visceral pleural or lymphovascular invasion) or invasion-negative (neither visceral pleural nor lymphovascular invasion) tumors by surgical approach (sublobar resection vs lobectomy).

RESULTS

Aside from age and pulmonary function, clinicopathologic characteristics of the patient subsets did not differ significantly, nor did 5-year recurrence-free survival rates of surgical subsets (sublobar resection vs lobectomy) in respective tumor groups (invasion-positive 78.9 vs 79.8%, p = 0.928; invasion-negative 80.2 vs 85.4%, p = 0.505). In multivariate analysis, dissected lymph node count was the sole parameter significantly impacting recurrence of stage I invasion-positive NSCLC (hazard ratio = 0.914, 95% confidence interval 0.845-0.988; p = 0.023). Sublobar resection was not a risk factor for recurrence.

CONCLUSIONS

Survival rates for patients with small-sized (≤2 cm) NSCLC and visceral pleural or lymphovascular invasion did not differ significantly, whether sublobar resection or lobectomy was done. Hence, completion lobectomy is unnecessary in this setting.