Cystic Primary Lung Cancer: Evolution of Computed Tomography Imaging Morphology Over Time.

PURPOSE: Primary lung cancers associated with cystic airspaces are increasingly being recognized; however, there is a paucity of data on their natural history. We aimed to evaluate the prevalence, pathologic, and imaging characteristics of cystic lung cancer in a regional thoracic surgery center with a focus on the evolution of computed tomography morphology over time. MATERIALS AND METHODS: Consecutive patients referred for potential surgical management of primary lung cancer between January 2016 and December 2018 were included. Clinical, imaging, and pathologic data were collected at the time of diagnosis and at the time of the oldest computed tomography showing the target lesion. Descriptive analysis was carried out. RESULTS: A total of 441 cancers in 431 patients (185 males, 246 females), median age 69.6 years (interquartile range: 62.6 to 75.3 y), were assessed. Overall, 41/441 (9.3%) primary lung cancers were cystic at the time of diagnosis. The remaining showed solid (67%), part-solid (22%), and ground-glass (2%) morphologies. Histopathology of the cystic lung cancers at diagnosis included 31/41 (76%) adenocarcinomas, 8/41 (20%) squamous cell carcinomas, 1/41 (2%) adenosquamous carcinoma, and 1/41 (2%) unspecified non-small cell lung carcinoma. Overall, 8/34 (24%) cystic cancers at the time of diagnosis developed from different morphologic subtype precursor lesions, while 8/34 (24%) cystic precursor lesions also transitioned into part-solid or solid cancers at the time of diagnosis. CONCLUSIONS: This study demonstrates that cystic airspaces within lung cancers are not uncommon, and may be seen transiently as cancers evolve. Increased awareness of the spectrum of cystic lung cancer morphology is important to improve diagnostic accuracy and lung cancer management.

Systemic Air Embolism Complicating Computed Tomography-guided Percutaneous Transthoracic Biopsy of Cavitary Lung Lesions: A Systematic Review.

PURPOSE: Cavitary lung lesions often pose a diagnostic challenge, and tissue sampling can be required to obtain a confident diagnosis. Many authors contend that a computed tomography-guided percutaneous transthoracic lung biopsy (PTLB) of a cavitary lung lesion places a patient at higher risk for systemic air embolism (SAE) compared with biopsy of a noncavitary lesion. MATERIALS AND METHODS: We reviewed the literature for studies of SAE complicating PTLB. We searched English-language articles indexed through PubMed, Embase, and Ovid Medline and included articles published up to March 31, 2020. RESULTS: We identified 10 case reports of SAE complicating PTLB, and 3 case-cohort studies comparing cavitary and noncavitary lesion biopsy. Among the case-cohort studies reviewed, 4 SAE occurred among 145 biopsies of cavitary lesions (2.7%), and 65 SAE occurred among 3050 biopsies of noncavitary lesions (2.1%). The pooled odds ratio of PTLB complicating SAE of cavitary lesions compared with noncavitary lesions was 1.29 (95% confidence interval: 0.47-3.60). No deaths following SAE after computed tomography-guided PTLB of cavitary lesions were reported in recent literature. CONCLUSIONS: On the basis of available evidence, air embolism rates are similar for PTLB of cavitary and noncavitary lesions. Additional research and registry studies are necessary to better understand this topic.

Radiological-pathological correlation of subsolid pulmonary nodules: A single centre retrospective evaluation of the 2011 IASLC adenocarcinoma classification system.

INTRODUCTION: The 2011 IASLC classification system proposes guidelines for radiologists and pathologists to classify adenocarcinomas spectrum lesions as preinvasive, minimally invasive adenocarcinoma (MIA), or invasive adenocarcinoma (IA). IA portends the worst clinical prognosis, and the imaging distinction between MIA and IA is controversial. MATERIALS AND METHODS: Subsolid pulmonary nodules resected by microcoil localization over a three-year period were retrospectively reviewed by three chest radiologists and a pulmonary pathologist. Nodules were classified radiologically based on preoperative computed tomography (CT), with the solid nodule component measured on mediastinal windows applied to high-frequency lung kernel reconstructions, and pathologically according to 2011 IASLC criteria. Radiology interobserver and radiological-pathological variability of nodule classification, and potential reasons for nodule classification discordance were assessed. RESULTS: Seventy-one subsolid nodules in 67 patients were included. The average size of invasive disease focus at histopathology was 5 mm (standard deviation 5 mm). Radiology interobserver agreement of nodule classification was good (Cohen's Kappa = 0.604, 95 % CI: 0.447 to 0.761). Agreement between consensus radiological interpretation and pathological category was fair (Cohen's Kappa = 0.236, 95 % CI: 0.054-0.421). Radiological and pathological nodule classification were concordant in 52 % (37 of 71) of nodules. The IASLC proposed CT solid component cut-off of 5 mm to distinguish MIA and IA yielded a sensitivity of 59 % and specificity of 80 %. Common reasons for nodule classification discordance included multiple solid components within a nodule on CT, scar and stromal collapse at pathology, and measurement variability. CONCLUSION: Solid component(s) within persistent part-solid pulmonary nodules raise suspicion for invasive adenocarcinoma. Preoperative imaging classification is frequently discordant from final pathology, reflecting interpretive and technical challenges in radiological and pathological analysis.

Image-guided Preoperative Localization of Pulmonary Nodules for Video-assisted and Robotically Assisted Surgery.

Video-assisted thoracic surgery (VATS) and robotically assisted surgery are used increasingly for minimally invasive diagnostic and therapeutic resection of pulmonary nodules. Unsuccessful localization of small, impalpable, or deep pulmonary nodules can necessitate conversion from VATS to open thoracotomy. Preoperative localization techniques performed by radiologists have improved the success rates of VATS resection for small and subsolid nodules. Any center at which VATS diagnostic resection of indeterminate pulmonary nodules is performed should be supported by radiologists who offer preoperative nodule localization. Many techniques have been described, including image-guided injection of radioisotopes and radiopaque liquids and placement of metallic wires, coils, and fiducial markers. These markers enable the surgeon to visualize the position of an impalpable nodule intraoperatively. This article provides details on how to perform each percutaneous localization technique, and a group of national experts with established nodule localization programs describe their preferred approaches. Special reference is made to equipment required, optimization of marker placement, prevention of technique-specific complications, and postprocedural treatment. This comprehensive unbiased review provides valuable information for those who are considering implementation or optimization of a nodule localization program according to workflow patterns, surgeon preference, and institutional resources in a particular center. ©RSNA, 2019.

Prediction of lung cancer risk at follow-up screening with low-dose CT: a training and validation study of a deep learning method.

Background: Current lung cancer screening guidelines use mean diameter, volume or density of the largest lung nodule in the prior computed tomography (CT) or appearance of new nodule to determine the timing of the next CT. We aimed at developing a more accurate screening protocol by estimating the 3-year lung cancer risk after two screening CTs using deep machine learning (ML) of radiologist CT reading and other universally available clinical information. Methods: A deep machine learning (ML) algorithm was developed from 25,097 participants who had received at least two CT screenings up to two years apart in the National Lung Screening Trial. Double-blinded validation was performed using 2,294 participants from the Pan-Canadian Early Detection of Lung Cancer Study (PanCan). Performance of ML score to inform lung cancer incidence was compared with Lung-RADS and volume doubling time using time-dependent ROC analysis. Exploratory analysis was performed to identify individuals with aggressive cancers and higher mortality rates. Findings: In the PanCan validation cohort, ML showed excellent discrimination with a 1-, 2- and 3-year time-dependent AUC values for cancer diagnosis of 0·968±0·013, 0·946±0·013 and 0·899±0·017. Although high ML score cohort included only 10% of the PanCan sample, it identified 94%, 85%, and 71% of incident and interval lung cancers diagnosed within 1, 2, and 3 years, respectively, after the second screening CT. Furthermore, individuals with high ML score had significantly higher mortality rates (HR=16·07, p<0·001) compared to those with lower risk. Interpretation: ML tool that recognizes patterns in both temporal and spatial changes as well as synergy among changes in nodule and non-nodule features may be used to accurately guide clinical management after the next scheduled repeat screening CT.

Predicting Malignancy Risk of Screen-Detected Lung Nodules-Mean Diameter or Volume.

OBJECTIVE: In lung cancer screening practice low-dose computed tomography, diameter, and volumetric measurement have been used in the management of screen-detected lung nodules. The aim of this study was to compare the performance of nodule malignancy risk prediction tools using diameter or volume and between computer-aided detection (CAD) and radiologist measurements. METHODS: Multivariable logistic regression models were prepared by using data from two multicenter lung cancer screening trials. For model development and validation, baseline low-dose computed tomography scans from the Pan-Canadian Early Detection of Lung Cancer Study and a subset of National Lung Screening Trial (NLST) scans with lung nodules 3 mm or more in mean diameter were analyzed by using the CIRRUS Lung Screening Workstation (Radboud University Medical Center, Nijmegen, the Netherlands). In the NLST sample, nodules with cancer had been matched on the basis of size to nodules without cancer. RESULTS: Both CAD-based mean diameter and volume models showed excellent discrimination and calibration, with similar areas under the receiver operating characteristic curves of 0.947. The two CAD models had predictive performance similar to that of the radiologist-based model. In the NLST validation data, the CAD mean diameter and volume models also demonstrated excellent discrimination: areas under the curve of 0.810 and 0.821, respectively. These performance statistics are similar to those of the Pan-Canadian Early Detection of Lung Cancer Study malignancy probability model with use of these data and radiologist-measured maximum diameter. CONCLUSION: Either CAD-based nodule diameter or volume can be used to assist in predicting a nodule's malignancy risk.

A Novel Approach Using Computed Tomography Angiograms to Predict Sternotomy or Complicated Anastomosis in Patients Undergoing Robotically Assisted Minimally Invasive Direct Coronary Artery Bypass.

OBJECTIVE: Robotically assisted minimally invasive direct coronary artery bypass is an alternative to sternotomy-based surgery in properly selected patients. Identifying the left anterior descending artery when it is deep in the epicardial fat can be particularly challenging through a 5- to 6-cm mini-thoracotomy incision. The objective of this study was to evaluate a technique for predicting conversion to sternotomy or complicated left anterior descending artery anastomosis using preoperative cardiac-gated computed tomography angiograms. METHODS: Retrospective review of 75 patients who underwent robotically assisted minimally invasive direct coronary artery bypass for whom a preoperative computed tomography angiogram was available. The distance from the left anterior descending artery to the myocardium was measured on a standardized "5-chamber" axial computed tomography view. The relative risk of sternotomy or complicated anastomosis was compared between patients whose left anterior descending artery was resting directly on the myocardium (left anterior descending artery to the myocardium distance = 0 mm) with those whose left anterior descending artery was resting above (left anterior descending artery to the myocardium distance > 0 mm). RESULTS: The average left anterior descending artery to the myocardium distance was 3.2 ± 2.6 mm (range = 0-11.5 mm). Fourteen patients (18.7%) had an left anterior descending artery to the myocardium distance of 0 mm. Of the entire group of 75 patients, 6 (8.0%) required conversion to sternotomy. Four others (5.3%) were reported to have a complication with the anastomosis intraoperatively. For patients with left anterior descending artery to the myocardium distance of 0 mm, the relative risk of sternotomy or complicated anastomosis was 18.0 (95% confidence interval = 4.3-75.6, P = 0.0001). CONCLUSIONS: In our experience, patients with left anterior descending artery to the myocardium distance of 0 mm were at significantly higher risk of either conversion to sternotomy or technically challenging anastomosis, with 8 (57.1%) of 14 patients in this group experiencing either end point. This novel measurement may be useful to identify patients who may have anatomy, which is not well suited to the robotically assisted minimally invasive direct coronary artery bypass approach.

Participant selection for lung cancer screening by risk modelling (the Pan-Canadian Early Detection of Lung Cancer [PanCan] study): a single-arm, prospective study.

BACKGROUND: Results from retrospective studies indicate that selecting individuals for low-dose CT lung cancer screening on the basis of a highly predictive risk model is superior to using criteria similar to those used in the National Lung Screening Trial (NLST; age, pack-year, and smoking quit-time). We designed the Pan-Canadian Early Detection of Lung Cancer (PanCan) study to assess the efficacy of a risk prediction model to select candidates for lung cancer screening, with the aim of determining whether this approach could better detect patients with early, potentially curable, lung cancer. METHODS: We did this single-arm, prospective study in eight centres across Canada. We recruited participants aged 50-75 years, who had smoked at some point in their life (ever-smokers), and who did not have a self-reported history of lung cancer. Participants had at least a 2% 6-year risk of lung cancer as estimated by the PanCan model, a precursor to the validated PLCOm2012 model. Risk variables in the model were age, smoking duration, pack-years, family history of lung cancer, education level, body-mass index, chest x-ray in the past 3 years, and history of chronic obstructive pulmonary disease. Individuals were screened with low-dose CT at baseline (T0), and at 1 (T1) and 4 (T4) years post-baseline. The primary outcome of the study was incidence of lung cancer. This study is registered with ClinicalTrials.gov, number NCT00751660. FINDINGS: 7059 queries came into the study coordinating centre and were screened for PanCan risk. 15 were duplicates, so 7044 participants were considered for enrolment. Between Sept 24, 2008, and Dec 17, 2010, we recruited and enrolled 2537 eligible ever-smokers. After a median follow-up of 5·5 years (IQR 3·2-6·1), 172 lung cancers were diagnosed in 164 individuals (cumulative incidence 0·065 [95% CI 0·055-0·075], incidence rate 138·1 per 10 000 person-years [117·8-160·9]). There were ten interval lung cancers (6% of lung cancers and 6% of individuals with cancer): one diagnosed between T0 and T1, and nine between T1 and T4. Cumulative incidence was significantly higher than that observed in NLST (4·0%; p<0·0001). Compared with 593 (57%) of 1040 lung cancers observed in NLST, 133 (77%) of 172 lung cancers in the PanCan Study were early stage (I or II; p<0·0001). INTERPRETATION: The PanCan model was effective in identifying individuals who were subsequently diagnosed with early, potentially curable, lung cancer. The incidence of cancers detected and the proportion of early stage cancers in the screened population was higher than observed in previous studies. This approach should be considered for adoption in lung cancer screening programmes. FUNDING: Terry Fox Research Institute and Canadian Partnership Against Cancer.

The Cost-Effectiveness of High-Risk Lung Cancer Screening and Drivers of Program Efficiency.

INTRODUCTION: Lung cancer risk prediction models have the potential to make programs more affordable; however, the economic evidence is limited. METHODS: Participants in the National Lung Cancer Screening Trial (NLST) were retrospectively identified with the risk prediction tool developed from the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. The high-risk subgroup was assessed for lung cancer incidence and demographic characteristics compared with those in the low-risk subgroup and the Pan-Canadian Early Detection of Lung Cancer Study (PanCan), which is an observational study that was high-risk-selected in Canada. A comparison of high-risk screening versus standard care was made with a decision-analytic model using data from the NLST with Canadian cost data from screening and treatment in the PanCan study. Probabilistic and deterministic sensitivity analyses were undertaken to assess uncertainty and identify drivers of program efficiency. RESULTS: Use of the risk prediction tool developed from the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial with a threshold set at 2% over 6 years would have reduced the number of individuals who needed to be screened in the NLST by 81%. High-risk screening participants in the NLST had more adverse demographic characteristics than their counterparts in the PanCan study. High-risk screening would cost $20,724 (in 2015 Canadian dollars) per quality-adjusted life-year gained and would be considered cost-effective at a willingness-to-pay threshold of $100,000 in Canadian dollars per quality-adjusted life-year gained with a probability of 0.62. Cost-effectiveness was driven primarily by non-lung cancer outcomes. Higher noncurative drug costs or current costs for immunotherapy and targeted therapies in the United States would render lung cancer screening a cost-saving intervention. CONCLUSIONS: Non-lung cancer outcomes drive screening efficiency in diverse, tobacco-exposed populations. Use of risk selection can reduce the budget impact, and screening may even offer cost savings if noncurative treatment costs continue to rise.

Guidelines for Management of Incidental Pulmonary Nodules Detected on CT Images: From the Fleischner Society 2017.

The Fleischner Society Guidelines for management of solid nodules were published in 2005, and separate guidelines for subsolid nodules were issued in 2013. Since then, new information has become available; therefore, the guidelines have been revised to reflect current thinking on nodule management. The revised guidelines incorporate several substantive changes that reflect current thinking on the management of small nodules. The minimum threshold size for routine follow-up has been increased, and recommended follow-up intervals are now given as a range rather than as a precise time period to give radiologists, clinicians, and patients greater discretion to accommodate individual risk factors and preferences. The guidelines for solid and subsolid nodules have been combined in one simplified table, and specific recommendations have been included for multiple nodules. These guidelines represent the consensus of the Fleischner Society, and as such, they incorporate the opinions of a multidisciplinary international group of thoracic radiologists, pulmonologists, surgeons, pathologists, and other specialists. Changes from the previous guidelines issued by the Fleischner Society are based on new data and accumulated experience. © RSNA, 2017 Online supplemental material is available for this article. An earlier incorrect version of this article appeared online. This article was corrected on March 13, 2017.

Transthoracic Computed Tomography-Guided Lung Nodule Biopsy: Comparison of Core Needle and Fine Needle Aspiration Techniques.

PURPOSE: To determine if there is a statistically significant difference in the computed tomography (CT)-guided trans-thoracic needle biopsy diagnostic rate, complication rate, and degree of pathologist confidence in diagnosis between core needle biopsy (CNB) and fine needle aspiration biopsy (FNAB). METHODS: A retrospective cohort design was used to compare the diagnostic biopsy rate, diagnostic confidence, and biopsy-related complications of pneumothorax, chest tube placement, pulmonary hemorrhage, hemoptysis, admission to hospital, and length of stay between 251 transthoracic needle biopsies obtained via CNB (126) or FNAB (125). Complication rates were assessed using imaging and clinical follow-up. Final diagnosis was confirmed via surgical pathology or clinical follow-up over a period of up to 10 years. RESULTS: CNB provided diagnostic samples in 91% and FNA in 80% of biopsies, which was statistically significant (P < .05). The sensitivities for CNB and FNAB were 89% (85 of 95) and 95% (84 of 88), respectively. The specificity of CNB was 100% (21 of 21) and for FNAB was 81% (2 of 11) with 2 false positives in the FNAB group. The differences in complication rate was not statistically significant for pneumothorax (50% vs 46%; determined by routine postbiopsy CT), chest tube (2% vs 4%), hemoptysis (4% vs 6%), and pulmonary hemorrhage (38% vs 47%) between FNAB and CNB, respectively. Seven patients requiring chest tube were admitted to hospital, 2 in the FNAB cohort for an average of 2.5 days and 5 in the CNB cohort for an average of 4.6 days. CONCLUSIONS: CNB provided more diagnostic samples with no statistical difference in complication rate.

Safety and Efficacy of Modified Preoperative Lung Nodule Microcoil Localization Without Pleural Marking: A Pilot Study.

PURPOSE: The purpose of this pilot study was to evaluate the safety and efficacy of preoperative computed tomography (CT)-guided percutaneous microcoil lung nodule localization without pleural marking compared with the established technique with pleural marking. MATERIALS AND METHODS: Sixty-three consecutive patients (66.7% female, mean age 61.6±11.4 y) with 64 lung nodules resected between October 2008 and January 2014 were retrospectively evaluated. Of the nodules, 29.7% (n=19) had microcoil deployment with pleural marking (control group) and 70.3% (n=45) had microcoil deployment without pleural marking (pilot group). Clinical, pathologic, and imaging characteristics, radiation dose, CT procedure and operating room time, and complete resection and complication rates were compared between the pilot and control groups. RESULTS: There was no significant difference in nodule size (P=0.552) or distance from the pleural surface (P=0.222) between the pilot and control groups. However, mean procedure duration (53.6±18.3 vs. 72.8±25.3 min, P=0.001) and total effective radiation dose (5.1±2.6 vs. 7.1±4.9 mSv, P=0.039) were significantly lower in the pilot group compared with the control group. CT procedure-related complications (P=0.483) [including pneumothoraces (P=0.769) and pulmonary hemorrhage (P=1.000)], operating room time (P=0.926), complete resection rates (P=0.520), intraoperative complications (P=0.549), and postoperative complications (P=1.000) were similar between the pilot and control groups. CONCLUSIONS: Preoperative CT-guided lung nodule microcoil localization performed without visceral pleural marking appears to decrease the CT procedure time and radiation dose while maintaining equivalent complete resection rates and procedural and surgical complications, when compared with microcoil localization performed with pleural marking.

Preoperative computed tomography-guided microcoil localization of small peripheral pulmonary nodules: a prospective randomized controlled trial.

OBJECTIVES: Growing, small, peripheral, pulmonary nodules in patients at high risk for lung cancer lead to requests for video-assisted thoracoscopic (VATS) resection for pathologic diagnosis. The purpose of this randomized controlled trial was to determine if preoperative localization using percutaneously placed computed tomography (CT)-guided platinum microcoils decreases the need for thoracotomy or VATS anatomic resection (segmentectomy/lobectomy) for diagnosis. METHODS: Patients with undiagnosed nodules of 15 mm or less were randomized to either no localization or preoperative microcoil localization. Coils were placed with the distal end deep to the nodule and the superficial end coiled on the visceral pleural surface with subsequent visualization by intraoperative fluoroscopy and VATS. Nodules were removed by VATS wedge excision using endostaplers. The primary outcome was a VATS wedge excision for pathologic diagnosis of the nodule without the need for either thoracotomy or VATS anatomic resection. RESULTS: Sixty patients were randomized and 56 underwent surgery between March 2010 and June 2012. Twenty-nine underwent microcoil localization and 27 did not. The baseline characteristics (age, sex, forced expiratory volume in the first second of expiration, nodule size/depth) were similar. The coil group had a higher rate of successful diagnosis with VATS wedge resection alone (27/29 vs 13/27; P < .001), decreased operative time to nodule excision (37 ± 39 vs 100 ± 67 minutes; P < .001), and reduced stapler firings (3.7 ± 2.0 vs 5.9 ± 31; P = .003) with no difference in total costs. Pathologic diagnoses included 14 benign nodules, 32 primary lung malignancies, and 10 metastases. There were no clinically significant complications related to the coil placement or wedge resection. CONCLUSIONS: Preoperative CT-guided microcoil localization decreases the need for thoracotomy or VATS anatomic resection for the diagnosis of small peripheral pulmonary nodules.

Qualitative and quantitative assessment of smoking-related lung disease: effect of iterative reconstruction on low-dose computed tomographic examinations.

PURPOSE: The purpose of this research is to examine the role that differing levels of adaptive statistical iterative reconstruction (ASIR) have on the qualitative and quantitative assessment of smoking-related lung disease. MATERIALS AND METHODS: Institutional board review approval was obtained. A total of 52 patients undergoing clinically indicated low-dose computed tomographic (CT) examinations of the chest (100 kVp, 65 mAs, mean radiation dose 1.0±0.12 mSv), with reconstruction of data with different levels of blended ASIR (0%, 40%, and 100%), were consented. Qualitative assessment of CT data sets was performed by 2 trained thoracic radiologists blinded to clinical history, spirometry, and quantitative data for the presence of emphysema (%/lung zone) and the degree of respiratory bronchiolitis. Quantitative analysis was performed (Apollo Image analysis, VIDA Diagnostics) to assess emphysema and airway measures of chronic obstructive pulmonary disease. RESULTS: The application of ASIR results in alterations in both qualitative and quantitative assessment of smoking-related lung disease. As levels of ASIR increased, both readers scored more respiratory bronchiolitis (P<0.05). At increased levels of ASIR (ie, 100% vs. 0%), the amount of emphysema measured (% below -950 HU) decreased, the number of airways measured diminished, and the airway thickness (Pi10mm) increased (P<0.001). CONCLUSIONS: The use of ASIR alters both the qualitative and quantitative assessment of smoking-related lung disease. Although a powerful tool to allow dose reduction, caution must be exercised when iterative reconstruction techniques are utilized when evaluating CT examinations for findings of chronic obstructive pulmonary disease.

Resource utilization and costs during the initial years of lung cancer screening with computed tomography in Canada.

BACKGROUND: It is estimated that millions of North Americans would qualify for lung cancer screening and that billions of dollars of national health expenditures would be required to support population-based computed tomography lung cancer screening programs. The decision to implement such programs should be informed by data on resource utilization and costs. METHODS: Resource utilization data were collected prospectively from 2059 participants in the Pan-Canadian Early Detection of Lung Cancer Study using low-dose computed tomography (LDCT). Participants who had 2% or greater lung cancer risk over 3 years using a risk prediction tool were recruited from seven major cities across Canada. A cost analysis was conducted from the Canadian public payer's perspective for resources that were used for the screening and treatment of lung cancer in the initial years of the study. RESULTS: The average per-person cost for screening individuals with LDCT was $453 (95% confidence interval [CI], $400-$505) for the initial 18-months of screening following a baseline scan. The screening costs were highly dependent on the detected lung nodule size, presence of cancer, screening intervention, and the screening center. The mean per-person cost of treating lung cancer with curative surgery was $33,344 (95% CI, $31,553-$34,935) over 2 years. This was lower than the cost of treating advanced-stage lung cancer with chemotherapy, radiotherapy, or supportive care alone, ($47,792; 95% CI, $43,254-$52,200; p = 0.061). CONCLUSION: In the Pan-Canadian study, the average cost to screen individuals with a high risk for developing lung cancer using LDCT and the average initial cost of curative intent treatment were lower than the average per-person cost of treating advanced stage lung cancer which infrequently results in a cure.

The Lung Reporting and Data System (LU-RADS): a proposal for computed tomography screening.

Despite the positive outcome of the recent randomized trial of computed tomography (CT) screening for lung cancer, substantial implementation challenges remain, including the clear reporting of relative risk and suggested workup of screen-detected nodules. Based on current literature, we propose a 6-level Lung-Reporting and Data System (LU-RADS) that classifies screening CTs by the nodule with the highest malignancy risk. As the LU-RADS level increases, the risk of malignancy increases. The LU-RADS level is linked directly to suggested follow-up pathways. Compared with current narrative reporting, this structure should improve communication with patients and clinicians, and provide a data collection framework to facilitate screening program evaluation and radiologist training. In overview, category 1 includes CTs with no nodules and returns the subject to routine screening. Category 2 scans harbor minimal risk, including <5 mm, perifissural, or long-term stable nodules that require no further workup before the next routine screening CT. Category 3 scans contain indeterminate nodules and require CT follow up with the interval dependent on nodule size (small [5-9 mm] or large [≥ 10 mm] and possibly transient). Category 4 scans are suspicious and are subdivided into 4A, low risk of malignancy; 4B, likely low-grade adenocarcinoma; and 4C, likely malignant. The 4B and 4C nodules have a high likelihood of neoplasm simply based on screening CT features, even if positron emission tomography, needle biopsy, and/or bronchoscopy are negative. Category 5 nodules demonstrate frankly malignant behavior on screening CT, and category 6 scans contain tissue-proven malignancies.