Optimal resection strategies for small-size lung cancer: Is a wedge enough? Is lobectomy too much?

Recently published large multicenter prospective clinical trials have demonstrated that sublobar resection is noninferior to lobectomy, the traditional treatment of choice, for peripherally located early-stage lung cancer. Most clinical trials and several retrospective studies published to date have used the consolidation-to-tumor ratio to define the indication for sublobar resection, as it is well known that the size of the solid portion seen on high-resolution computed tomography is highly correlated with pathologic invasiveness. However, it is difficult to accurately predict pathologic features that may increase the risk of locoregional recurrence, such as specific adenocarcinoma subtypes or spread through air spaces, based on imaging characteristics alone, and the location of the nodule also should be considered one of the important factors in obtaining an adequate parenchymal resection margin. In this article, we summarize the results of the most recently published clinical trials related to sublobar resection and discuss various factors that should be considered for optimal candidate selection for sublobar resection.

Using the robotic platform in the therapy of multifocal ground glass opacities

Due to their association with invasive adenocarcinoma, ground glass opacities that reach 3 cm in size, develop a solid component ≥2 mm on mediastinal windows, or exhibit ≥25% annual growth warrant operative resection. Minimally invasive techniques are preferred given that approximately one third of patients will present with multifocal focal disease and may require additional operations. A robotic-assisted thoracoscopic surgical approach can be used with percutaneous or bronchoscopic localization techniques and are compatible with developing intraoperative molecular targeting techniques.

Complete Lymphadenectomy for Clinical Stage I Lepidic Adenocarcinoma of the Lung: Is it justified?

The role of a systematic lymphadenectomy in patients undergoing surgery for clinical stage I lung lepidic adenocarcinoma is still unclear. In the last years, some authors have advocated the possibility to avoid a complete lymph-node dissection in this setting. Results of patients who received systematic hilar-mediastinal nodal dissection for this oncologic condition are here reported. Between 2012 and March 2019, 135 consecutive patients underwent lung resection for clinical stage I lepidic adenocarcinoma, at our institution. Only patients (n=98) undergoing lobectomy or sublobar resection associated with systematic hilar-mediastinal nodal dissection were retrospectively enrolled in the study. Patients' mean age was 67.8±8.7 years (range 37-84). Three were 52 females and 46 males. Resection was lobectomy in 77.6% (n=76) and sublobar in 22.4% (n=22). All the resections were complete (R0). Histology was lepidic predominant adenocarcinoma in 85 cases and minimally invasive adenocarcinoma in 13 cases. At pathologic examination, N0 was confirmed in 78 patients (79.6%), while N+ was found in 20 cases (20.4%), (N1 in 12, 12.2% and N2 in 8, 8.2%). No mortality occurred. Complication rate was 8.2%. At a median follow-up of 45.5 months, recurrence rate was 26.5%. Disease-free 5-year survival was 98.6% for stage I, 75% for stage II and 45% for stage III, p<0.001. A complete nodal dissection can reveal occult nodal metastases in lepidic adenocarcinoma patients and can increase the accuracy of pathologic staging. N1/N2 disease is a negative prognostic factor for this histology. A systematic lymph-node dissection should be considered even in this setting.

Prediction of the Invasiveness of Ground-Glass Nodules in Lung Adenocarcinoma by Radiomics Analysis Using High-Resolution Computed Tomography Imaging

Background

Pure ground-glass nodules (pGGNs) have been considered inert tumors due to their biological behavior; however, their prognosis is not completely consistent because of differences in internal pathological component. The aim of this study was to explore whether radiomics can be used to identify the invasiveness of pGGNs.

Methods

The retrospective study received the relevant ethical approval. After postoperative pathological confirmation, sixty-five patients with lung adenocarcinoma pGGNs (≤30 mm) were enrolled in this study from January 2015 to October 2018. All the cases were randomly divided into training and test groups in a 7:3 ratio. In total, 385 radiomics features were obtained from HRCT images, and then least absolute shrinkage and selection operator (LASSO) logistic regression was applied to the training group to obtain optimal features to distinguish the invasion degree of lesions. The diagnostic efficiency of the radiomics model was estimated by the area under the curve (AUC) of the receiver operating curve (ROC), and verified by the test group.

Results

The optimal features (“GLCMEntropy_angle135_offset1” and “Sphericity”) were selected after applying the LASSO regression to develop the proposed radiomics model. This prediction model exhibited good differentiation between pre-invasive and invasive lesions. The AUC for the test group was 0.824 (95%CI: 0.599-1.000), indicating that the radiomics model has some prediction ability.

Conclusion

The HRCT radiomics features can discriminate pre-invasive from invasive lung adenocarcinoma pGGNs. This non-invasive method can provide more information for surgeons before operation, and can also predict the prognosis of patients to some extent.

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.

Consolidation volume and integration of computed tomography values on three-dimensional computed tomography may predict pathological invasiveness in early lung adenocarcinoma

PURPOSE

To investigate the relationship between three-dimensional computed tomography (3D-CT) findings and pathological invasiveness in lung adenocarcinoma.

METHODS

We retrospectively evaluated 95 patients who underwent surgical resection of lung adenocarcinoma of ≤ 20 mm. The diameters, volumes, and CT values of tumor consolidation were analyzed. We defined the modified CT value by setting air as 0 and water as 1000 and assumed a correlation with pathological invasiveness. Pre-invasive lesions and minimally invasive adenocarcinomas were classified as non-invasive adenocarcinoma. We compared the clinico-radiological features with pathological invasiveness. Receiver operator characteristic (ROC) curves and recurrence-free survival curves were constructed.

RESULTS

Twenty-six non-invasive adenocarcinomas and 69 invasive adenocarcinomas were evaluated. The multivariate analysis revealed that the consolidation volume and the integration of modified CT values were the most important predictors of pathological invasion. The area under the ROC curve and the cut-off values of the consolidation volume were 0.868 and 75 mm³, respectively. The area under the ROC curve and the cut-off values of the integration of modified CT values were 0.871 and 80,000, respectively. There was no recurrence in cases with values below the cut-off across all parameters.

CONCLUSION

The consolidation volume and integration of modified CT values were shown to be highly predictive of pathological invasiveness.

Approach to the Subsolid Nodule

Most focal persistent ground glass nodules (GGNs) do not progress over 10 years. Research suggests that GGNs that do not progress, those that do, and solid lung cancers are fundamentally different diseases, although histologically they seem similar. Surveillance of GGNs to identify those that gradually progress is safe and does not risk losing a window. GGNs with 5 mm solid component or less than 10 mm consolidation (mediastinal and lung windows, respectively, on thin slice CT) are highly curable with resection. The optimal type of resection is unclear; sublobar resection is reasonable but an adequate margin is critically important.

Evaluation of ground glass nodules

PURPOSE OF REVIEW

Ground glass nodules (GGNs) represent an indolent subset of lung nodules including preinvasive nonsmall-cell lung cancer associated with a favorable prognosis and low risk for progression. Increased performance of screening cat-scan (CT) for high-risk patients has identified an increasing number of GGNs. The management of these nodules is founded mostly on single institution data and currently no universally accepted recommendations help guide clinicians managing these patients.

RECENT FINDINGS

The solid component within a GGN is the key determinant of prognosis and is best defined by evaluating nodule density on mediastinal windows of a chest CT. When a GGN is small (<3 cm), associated with minimal change in size (<25% growth per year), and there is no demonstration of a significant solid component on mediastinal windows (<2 mm in diameter), patients can be safely observed with serially imaging. These imaging features also help distinguish patients that may harbor early-stage lung cancers that benefit from local treatment options.

SUMMARY

The majority of GGNs do not undergo significant progression during surveillance. Evidence of nodule progression on interval imaging may be a trigger for consideration of a local treatment option such as surgical resection. Large prospective studies are needed in the United States to validate the more robust data derived from Asian studies to help formulate formal recommendations for surveillance and treatment. Future improvements in imaging and the molecular characterization of these GGNs may further refine which patients are at risk for progression.

CT and histopathologic characteristics of lung adenocarcinoma with pure ground-glass nodules 10 mm or less in diameter

OBJECTIVE

To evaluate CT and histopathologic features of lung adenocarcinoma with pure ground-glass nodule (pGGN) ≤10 mm in diameter.

METHODS

CT appearances of 148 patients (150 lesions) who underwent curative resection of lung adenocarcinoma with pGGN ≤10 mm (25 atypical adenomatous hyperplasias, 42 adenocarcinoma in situs, 38 minimally invasive adenocarcinomas, and 45 invasive pulmonary adenocarcinomas) were analyzed for lesion size, density, bubble-like sign, air bronchogram, vessel changes, margin, and tumour-lung interface. CT characteristics were compared among different histopathologic subtypes. Univariate and multivariate analysis were used to assess the relationship between CT characteristics of pGGN and lesion invasiveness, respectively.

RESULTS

There were statistically significant differences among histopathologic subtypes in lesion size, vessel changes, and tumour-lung interface (P<0.05). Univariate analysis revealed significant differences of vessel changes, margin and tumour-lung interface between preinvasive and invasive lesions (P<0.05). Logistic regression analysis showed that the vessel changes, unsmooth margin and clear tumour-lung interface were significant predictive factors for lesion invasiveness, with odds ratios (95% CI) of 2.57 (1.17-5.62), 1.83 (1.25-2.68) and 4.25 (1.78-10.14), respectively.

CONCLUSION

Invasive lesions are found in 55.3% of subcentimeter pGGNs in our cohort. Vessel changes, unsmooth margin, and clear lung-tumour interface may indicate the invasiveness of lung adenocarcinoma with subcentimeter pGGN.

KEY POINTS

• Invasive lesions were found in 55.3% of lung adenocarcinomas with subcentimeter pGGNs • Lesion size, vessel changes, and tumour-lung interface showed different among histopathologic subtypes • Vessel changes, unsmooth margin and clear tumour-lung interface were predictors for lesion invasiveness.

Treatment of simultaneously discovered lung cancer and cardiovascular disease: a 20-year single-institution experience

PURPOSE

To propose a treatment strategy for simultaneously discovered non-small cell lung cancer (NSCLC) and cardiovascular disease (CVD).

METHODS

Of 1302 patients who underwent surgery for NSCLC, CVD requiring invasive treatment was simultaneously discovered in 33 (3 %). The details of the treatments as well as the short- and long-term outcomes of pulmonary resection were analyzed.

RESULTS

CVD included coronary artery disease in 20 patients, valvular disease in 6, abdominal aortic aneurysm in 5, and congenital heart disease in 2. Twenty-six patients underwent two-stage treatment, while seven received simultaneous surgery. In 23 patients whose treatment for CVD preceded that for lung cancer, the median interval between those treatments was 78 days (range 18-197 days). Postoperative complications occurred in 8 (31 %) of 26 patients who underwent 2-stage treatment and in 3 (43 %) of 7 who underwent simultaneous surgery. Notably, of 3 patients who underwent lobectomy or bilobectomy, 2 (67 %) experienced respiratory dysfunction that required intubation. The 5-year overall survival rate of all 33 patients was 84.5 %.

CONCLUSION

The outcomes of two-stage treatment in the present cohort were favorable. Given our experience, simultaneous surgery for lung cancer and CVD should, therefore, be selected only for patients who may benefit from that strategy.

Early lung cancer with lepidic pattern: adenocarcinoma in situ, minimally invasive adenocarcinoma, and lepidic predominant adenocarcinoma

PURPOSE OF REVIEW

This review gives a comprehensive overview on recent developments in the classification of neoplastic lung lesions with lepidic growth patterns, comprising the adenocarcinoma (ADC) precursor lesions atypical adenomatous hyperplasia (AAH), adenocarcinoma in situ (AIS), and minimally invasive adenocarcinoma (MIA) as well as lepidic predominant adenocarcinoma (LPA).

RECENT FINDINGS

The concept of a continuum between the precursor lesions AAH and AIS to MIA and frankly invasive ADC is backed by a wealth of recent data showing a gradual decrease in overall survival from 100% for AAH, AIS, and MIA to moderately lower rates for LPA. Further, it has been shown that the morphologic categorization of these tumors can be done with reasonable reliability and that nonmucinous lepidic tumors show distinct molecular alterations with high rates of epidermal growth factor receptor mutations. Importantly, lepidic tumor growth is also mirrored by specific characteristics in computed tomography images, arguing for a combined assessment of histomorphology and imaging data for an optimized classification of lepidic neoplasms.

SUMMARY

The validity and clinical importance of the novel concept of ADC precursor lesions and LPA have been confirmed by clinical, radiological, morphological, and molecular data. Thereby, it has evolved into a valuable tool to aid in clinical decision-making.

Advances in lung adenocarcinoma classification: a summary of the new international multidisciplinary classification system (IASLC/ATS/ERS)

Due to advances in the understanding of lung adenocarcinoma since the advent of its 2004 World Health System classification, an international multidisciplinary panel [sponsored by the International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European Respiratory Society (ERS)] has recently updated the classification system for lung adenocarcinoma, the most common histologic type of lung cancer. Here, we summarize and highlight the new criteria and terminology, certain aspects of its clinical relevance and its potential treatment impact, and future avenues of research related to the new system.