Subsolid pulmonary nodule management and lung adenocarcinoma classification: state of the art and future trends

Computed Tomography-Guided Microcoil Localization of Pulmonary Nodules: Effects of Multiple Punctures

BACKGROUND

The aim of the study is to analyze the effect of multiple punctures in computed tomography (CT)-guided microcoil localization of pulmonary nodules with other risk factors for common complications.

METHODS

Consecutive patients who underwent CT-guided microcoil localization and subsequent video-assisted thoracoscopic surgery (VATS) between January 2020 and February 2021 were enrolled. Nodules successfully located after only one puncture were defined as the single puncture group, and nodules requiring two or more punctures were defined as the multiple puncture group. Binary logistic regression analysis was performed to assess the relationship between the number of punctures and pneumothorax and intrapulmonary hemorrhage.

RESULTS

A total of 121 patients were included. There were 98 (68.1%) pulmonary nodules in the single puncture group compared with 46 (31.9%) nodules in the multiple puncture group. The frequencies of pneumothorax and intrapulmonary hemorrhage were higher in the multiple puncture group than in the single puncture group (p = 0.019 and <0.001, respectively). Binary logistic regression demonstrated that independent risk factors for developing pneumothorax included lateral positioning of the patient (p < .001) and prone positioning (p = 0.014), as well as multiple punctures (p = 0.013). Independent risk factors for intrapulmonary hemorrhage included the distance between the distal end of the coil and the surface of the pleura (p = 0.033), multiple punctures (p = 0.003), and passage through the pulmonary vasculature (p < 0.001).

CONCLUSION

Multiple punctures resulted in an increased incidence of pneumothorax and intrapulmonary hemorrhage compared with single puncture during CT-guided microcoil localization of pulmonary nodules and were independently associated with both pneumothorax and intrapulmonary hemorrhage.

Pearls and Pitfalls in Lung Cancer CT Screening

Annual LDCT lung cancer screening is recommended by the United States Preventive Services Task Force (USPSTF) for high-risk population based on the results from the National Lung Cancer Screening Trial (NLST) that showed a significant (20%) reduction in lung cancer-specific mortality rate with the use of annual low-dose computed tomography (LDCT) screening. More recently, the benefits of lung cancer screening were confirmed by the Dutch- Belgian NELSON trial in Europe. With the implementation of lung screening in large scale, knowledge of the limitations related to false positive, false negative and other potential pitfalls is essential to avoid misdiagnosis. This review outlines the most common potential pitfalls in the characterization of screen-detected lung nodules that include artifacts in LDCT, benign nodules that mimic lung cancer, and causes of false negative evaluations of lung cancer with LDCT and PET/CT studies. Awareness of the spectrum of potential pitfalls in pulmonary nodule detection and characterization, including equivocal or atypical presentations, is important for avoiding misinterpretation that can alter patient management.

Long-Term Follow-Up of Ground-Glass Nodules After 5 Years of Stability

INTRODUCTION

Small ground-glass nodules (GGNs) or those with an indeterminate risk on low-dose computed tomography (LDCT) of the chest are recommended at 5-year follow-up, but the rationale for follow-up beyond 5 years is unclear.

METHODS

An observational study was conducted to investigate the natural course of GGNs that had been stable for 5 years by LDCT over 10 years. All eligible GGNs were detected during regular health checkups. Baseline characteristics were compared between GGNs with and without growth. Risk factors for GGN growth were evaluated.

RESULTS

A total of 208 GGNs were detected in 160 participants. GGN growth was identified in 27 (13.0%) GGNs during a follow-up of 136 months on LDCT scans. In approximately 95% of these GGNs, the initial size was less than 6 mm, with 3.2 mm of growth over 8.5 years. Biopsies were performed in 3 of 27 GGNs, revealing adenocarcinoma. In 8 of 27 cases, GGN growth preceded the development of a new solid component. In a multivariate analysis, bubble lucency (p = 0.001), a history of cancer other than lung cancer (p = 0.036), and development of a new solid component (p < 0.001) were significant risk factors for GGN growth.

CONCLUSIONS

GGNs should not be ignored, even when smaller than 6 mm and stable for 5 years, especially when a new solid component appears during follow-up.

Visual discrimination of screen-detected persistent from transient subsolid nodules: An observer study

Purpose

To evaluate whether, and to which extent, experienced radiologists are able to visually correctly differentiate transient from persistent subsolid nodules from a single CT examination alone and to determine CT morphological features to make this differentiation.

Materials and methods

We selected 86 transient and 135 persistent subsolid nodules from the National Lung Screening Trial (NLST) database. Four experienced radiologists visually assessed a predefined list of morphological features and gave a final judgment on a continuous scale (0–100). To assess observer performance, area under the receiver operating characteristic (ROC) curve was calculated. Statistical differences of morphological features between transient and persistent lesions were calculated using Chi-square. Inter-observer agreement of morphological features was evaluated by percentage agreement.

Results

Forty-nine lesions were excluded by at least 2 observers, leaving 172 lesions for analysis. On average observers were able to differentiate transient from persistent subsolid nodules ≥ 10 mm with an area under the curve of 0.75 (95% CI 0.67–0.82). Nodule type, lesion margin, presence of a well-defined border, and pleural retraction showed significant differences between transient and persistent lesions in two observers. Average pair-wise percentage agreement for these features was 81%, 64%, 47% and 89% respectively. Agreement for other morphological features varied from 53% to 95%.

Conclusion

The visual capacity of experienced radiologists to differentiate persistent and transient subsolid nodules is moderate in subsolid nodules larger than 10 mm. Performance of the visual assessment of CT morphology alone is not sufficient to generally abandon a short-term follow-up for subsolid nodules.

Anatomic bisegmentectomy for synchronous lung adenocarcinoma

Modern thoracic surgery requires the ability to manage patients with ground glass opacities (GGO). However, due to the lack of a standardize approach in our institution these cases are discussed in the tumor board. We here present our therapeutic rationale in a case of a patient with multiple GGOs, who underwent an en-bloc anatomic bisegmentectomy as surgical treatment for a synchronous lung adenocarcinoma.

Malignancy estimation of Lung-RADS criteria for subsolid nodules on CT: accuracy of low and high risk spectrum when using NLST nodules

Purpose

Lung-RADS proposes malignancy probabilities for categories 2 (<1%) and 4B (>15%). The purpose of this study was to quantify and compare malignancy rates for Lung-RADS 2 and 4B subsolid nodules (SSNs) on a nodule base.

Methods

We identified all baseline SSNs eligible for Lung-RADS 2 and 4B in the National Lung Screening Trial (NLST) database. Solid cores and nodule locations were annotated using in-house software. Malignant SSNs were identified by an experienced radiologist using NLST information. Malignancy rates and percentages of persistence were calculated.

Results

Of the Lung-RADS 2SSNs, 94.3% (1790/1897) could be located on chest CTs. Likewise, 95.1% (331/348) of part-solid nodules ≥6 mm in diameter could be located. Of these, 120 had a solid core ≥8 mm, corresponding to category 4B. Category 2 SSNs showed a malignancy rate of 2.5%, exceeding slightly the proposed rate of <1%. Category 4B SSNs showed a malignancy rate of 23.9%. In both categories one third of benign lesions were transient.

Conclusion

Malignancy probabilities for Lung-RADS 2 and 4B generally match malignancy rates in SSNs. An option to include also category 2 SSNs for upgrade to 4X designed for suspicious nodules might be useful in the future. Integration of short-term follow-up to confirm persistence would prevent unnecessary invasive work-up in 4B SSNs.

Key points

• Malignancy probabilities for Lung-RADS 2/4B generally match malignancy risks in SSNs.

• Transient rate between low-risk Lung-RADS 2 and high-risk 4B lesions were similar.

• Upgrade of highly suspicious Lung-RADS 2 SSNs to Lung-RADS 4X might be useful.

• Up to one third of the benign high-risk Lung-RADS 4B lesions were transient.

• Short-term follow-up confirming persistence would avoid unnecessary invasive work-up of 4B lesions.

CT-guided microcoil VATS resection of lung nodules: a single-centre experience and review of the literature

BACKGROUND

Video-assisted thoracoscopic surgery (VATS) is standard of care for small lung resections at many centres. Computed tomography (CT)-guided insertion of microcoils can aid surgeons in performing VATS resections for non-palpable lung nodules deep to the lung surface.

METHODS

Retrospective analysis of CT-guided microcoil insertions prior to VATS lung resection at a single institution from October 2008 to January 2014.

RESULTS

A total of 63 patients were included (37% male, mean age 61.6±11.4 years). Forty-two patients (67%) had a history of smoking, with 10 current smokers. Sixty one (97%) patients underwent wedge resection and 3 (5%) patients had segmentectomy. Three (5%) patients required intra-operative staple line re-resection for positive or close margins. Eleven (17%) patients had a completion lobectomy, 5 of which were during the same anaesthetic. The average time between the CT-guided insertion and start of operation was 136.6±89.0 min, and average operative time was 84.0±53.3 min. The intra-operative complication rate was 5% (n=3), including 1 episode of hemoptysis, and 2 conversions to thoracotomy. The post-operative complication rate was 8% (5 patients), and included 2 air leaks, 1 hemothorax (drop in hemoglobin), 1 post chest tube removal pneumothorax, and one venous infarction of the lingula after lingula-sparing lobectomy requiring completion lobectomy. . Average post-operative length of stay was 2.2 days. A diagnosis was made for all patients.

CONCLUSIONS

CT-guided microcoil insertion followed by VATS lobectomy is safe, with short operative times, short length of stay and 100% diagnosis of small pulmonary nodules. This technique will become more important in the future with increasing numbers of small nodules detected on CT as part of lung cancer screening programs.

What do we know about ground-glass opacity nodules in the lung?

Ground-glass opacity nodules (GGNs) in the lung attract clinical attention owing to their increasing incidence, unique natural course, and association with lung adenocarcinoma. A long and indolent course of a GGN makes it difficult to manage. Current extensive clinical, radiological, pathological, and genetic studies on GGNs have shed light on their pathogenesis and allowed development of a reliable strategy of management. The present editorial provides answers to clinical questions related to GGNs, such as the natural course, follow-up, prediction of growth, and resection techniques. Finally, I discuss the etiology of GGNs, which has not been fully elucidated so far.

Surgical resection of nodular ground-glass opacities without percutaneous needle aspiration or biopsy

BACKGROUND

Percutaneous needle aspiration or biopsy (PCNA or PCNB) is an established diagnostic technique that has a high diagnostic yield. However, its role in the diagnosis of nodular ground-glass opacities (nGGOs) is controversial, and the necessity of preoperative histologic confirmation by PCNA or PCNB in nGGOs has not been well addressed.

METHODS

We here evaluated the rates of malignancy and surgery-related complications, and the cost benefits of resecting nGGOs without prior tissue diagnosis when those nGGOs were highly suspected for malignancy based on their size, radiologic characteristics, and clinical courses. Patients who underwent surgical resection of nGGOs without preoperative tissue diagnosis from January 2009 to October 2013 were retrospectively analyzed.

RESULTS

Among 356 nGGOs of 324 patients, 330 (92.7%) nGGOs were resected without prior histologic confirmation. The rate of malignancy was 95.2% (314/330). In the multivariate analysis, larger size was found to be an independent predictor of malignancy (odds ratio, 1.086; 95% confidence interval, 1.001-1.178, p =0.047). A total of 324 (98.2%) nGGOs were resected by video-assisted thoracoscopic surgery (VATS), and the rate of surgery-related complications was 6.7% (22/330). All 16 nGGOs diagnosed as benign nodules were resected by VATS, and only one patient experienced postoperative complications (prolonged air leak). Direct surgical resection without tissue diagnosis significantly reduced the total costs, hospital stay, and waiting time to surgery.

CONCLUSIONS

With careful selection of nGGOs that are highly suspicious for malignancy, surgical resection of nGGOs without tissue diagnosis is recommended as it reduces costs and hospital stay.

Lung cancer imaging

Lung cancer remains the leading cause of cancer-related deaths in the US. Imaging plays an important role in the diagnosis, staging, and follow-up evaluation of patients with lung cancer. With recent advances in technology, it is important to update and standardize the radiological practices in lung cancer evaluation. In this article, the authors review the main clinical applications of different imaging modalities and the most common radiological presentations of lung cancer.