Paragonimiasis Misdiagnosed as Pulmonary Tuberculosis: A Case Report.

Paragonimiasis is a zoonosis caused by the ingestion of raw or undercooked crustaceans parasitized with metacercaria of Paragonimus spp. In Peru, Cajamarca is considered an endemic region for paragonimiasis. A 29-year-old man from the department of San Martín, Peru presented with a three-year history of cough, chest pain, fever, and hemoptysis. Treatment for tuberculosis (TB) was initiated even with negative results for sputum acid-fast bacillus (AFB), due to the patient's clinical characteristics and the high prevalence of the condition in the region. After eight months, due to the lack of any clinical improvement, he was referred to a regional hospital, where Paragonimus eggs were evidenced in direct sputum cytology. The patient received treatment with triclabendazole and showed clinical and radiological improvement. It is important to consider eating habits, even in non-endemic areas, for diagnosing paragonimiasis in patients with TB symptoms who do not respond to a specific treatment.

Restenosis Following Bronchoscopic Airway Stenting for Complex Tracheal Stenosis.

BACKGROUND: Nonsurgical patients with complex postintubation tracheal stenosis (PITS) and tracheostomy-associated tracheal stenosis (PTTS) often require airway stenting. However, the optimal approach is unknown. Identifying patients at higher risk for restenosis after stent removal may allow the treating physician to individualize the vigilance and duration of airway stenting, and help optimize outcomes. METHODS: This was a single-center retrospective analysis of prospectively collected data on all patients with complex PITS and/or PTTS treated with protocolized bronchoscopic airway stenting over a consecutive 16-year period. The primary outcome analyzed was restenosis rate at 1 year after stent removal. Predictors for restenosis and factors influencing risk for death during stent therapy were also assessed. RESULTS: Of the 181 subjects treated with silicone airway stenting, 128 were available for analysis of the primary outcome. Restenosis by 1 year after stent removal occurred in 58%. Independent predictors for restenosis were coexisting diabetes [odd ratio (OR)=3.10, 95% confidence interval (CI)=1.04-9.24; P =0.04], morbid obesity (OR=3.13, 95% CI=1.20-8.17; P =0.02), and occurrence of stent-associated complications requiring bronchoscopic management (OR=2.13, 95% CI=1.12-4.03; P =0.02). The overall mortality during the initial stenting period was 14%, and a silicone Y-stent was associated with a higher risk of death (OR=3.58, 95% CI=1.40-9.14; P =0.008). CONCLUSION: Tracheal restenosis after silicone stent therapy for complex PITS and PTTS is common and more likely to occur in patients with diabetes, morbid obesity, and frequent stent-associated complications. Mortality risk during stent therapy is not negligible, and a Y-stent should be utilized only after careful consideration. These findings may be incorporated into the approach to bronchoscopic airway stenting in these patients.

Ion: Technology and Techniques for Shape-sensing Robotic-assisted Bronchoscopy.

PURPOSE: This report describes the Ion Endoluminal System (Intuitive Surgical, Inc, Sunnyvale, CA) and practices for safe and effective use in patients with small peripheral pulmonary nodules (PPNs). DESCRIPTION: This shape-sensing robotic-assisted bronchoscopy system allows airway visualization and navigation to reach and biopsy small PPNs through a stable platform. The system provides 3-dimensional mapping and visualization of the airways, a flexible and fully articulating 3.5-mm (outer diameter) catheter, a peripheral vision probe, and system-specific biopsy needles. EVALUATION: The Ion Endoluminal System was evaluated in an ongoing prospective, multicenter trial including 241 patients with 270 PPNs (largest mean cardinal measurement, 18.8 ± 6.5 mm). Mean time to register and navigate decreased from 10 minutes in the first 10 cases to 7 minutes in the subsequent cases. Asymptomatic pneumothorax occurred in 8 patients (3.3%), 1 (0.4%) with pigtail catheter placement. Two patients (0.8%) experienced airway bleeding; both cases of bleeding resolved within 5 minutes of tamponade. CONCLUSIONS: The Ion Endoluminal System's unique shape-sensing technology can be leveraged to facilitate localization and sampling of PPNs and potentially improve diagnostic accuracy.

One-session bilateral sequential whole lung lavage (OSBSWLL) for the management of pulmonary alveolar proteinosis.

BACKGROUND: Whole Lung Lavage (WLL) has been an important part in the management of Pulmonary Alveolar Proteinosis (PAP) since it improves radiologic and clinical parameters. Bilateral WLL is usually performed in two sessions on different days. Few case reports have described one-session bilateral sequential lung lavage (OSBSWLL), and none have described ambulatory management (same-day discharge). METHODS: Demographic characteristics, physiologic parameters, procedure details and outcomes were retrospectively collected on consecutive patients who underwent OSBSWLL for PAP following an ambulatory protocol stablished in our institution. RESULTS: A total of 13 patients underwent 30 OSBSWLL (61.5% male; mean age 40). The mean SpO2 was 90% (IQR 9) and 94% (IQR 6), before and after OSBSWLL respectively. In 63.3% of cases, patients were discharged home the same day of procedure. Only in two cases (6.6%), patients required post-procedure prolonged mechanical ventilation (> 4 h) due to persistent hypoxia. CONCLUSIONS: OSBSWLL can be performed with same-day discharge.

Shape-sensing robotic-assisted bronchoscopy for pulmonary nodules: initial multicenter experience using the Ion™ Endoluminal System.

BACKGROUND: Traditional bronchoscopy provides limited approach to peripheral nodules. Shape-sensing robotic-assisted bronchoscopy (SSRAB, Ion™ Endoluminal System) is a new tool for minimally invasive peripheral nodule biopsy. We sought to answer the research question: Does SSRAB facilitate sampling of pulmonary nodules during bronchoscopists' initial experience? METHODS: The lead-in stage of a multicenter, single-arm, prospective evaluation of the Ion Endoluminal System (PRECIsE) is described. Enrolled subjects ≥ 18 years old had recent computed tomography evidence of one or more solid or semi-solid pulmonary nodules ≥ 1.0 to ≤ 3.5 cm in greatest dimension and in any part of the lung. Subjects were followed at 10- and 30-days post-procedure. This stage provided investigators and staff their first human experience with the SSRAB system; safety and procedure outcomes were analyzed descriptively. Neither diagnostic yield nor sensitivity for malignancy were assessed in this stage. Categorical variables are summarized by percentage; continuous variables are summarized by median/interquartile range (IQR). RESULTS: Sixty subjects were enrolled across 6 hospitals; 67 nodules were targeted for biopsy. Median axial, coronal and sagittal diameters were < 18 mm with a largest cardinal diameter of 20.0 mm. Most nodules were extraluminal and distance from the outer edge of the nodule to the pleura or nearest fissure was 4.0 mm (IQR: 0.0, 15.0). Median bronchial generation count to the target location was 7.0 (IQR: 6.0, 8.0). Procedure duration (catheter-in to catheter-out) was 66.5 min (IQR: 50.0, 85.5). Distance from the catheter tip to the closest edge of the virtual nodule was 7.0 mm (IQR: 2.0, 12.0). Biopsy completion was 97.0%. No pneumothorax or airway bleeding of any grade was reported. CONCLUSIONS: Bronchoscopists leveraged the Ion SSRAB's functionality to drive the catheter safely in close proximity of the virtual target and to obtain biopsies. This initial, multicenter experience is encouraging, suggesting that SSRAB may play a role in the management of pulmonary nodules. Clinical Trial Registration identifier and date NCT03893539; 28/03/2019.

Questionnaires or Serum Immunoglobulin G Testing in the Diagnosis of Hypersensitivity Pneumonitis among Patients with Interstitial Lung Disease.

Rationale: Hypersensitivity pneumonitis (HP) results from exposure to a variety of stimuli, which are challenging to identify. Questionnaires and serum immunoglobulin G (IgG) testing are methods to identify potentially causative exposures.Objectives: To perform a systematic review to determine the usefulness of questionnaires and serum IgG testing in identifying exposures that may have caused HP.Methods: This systematic review informed an international, multidisciplinary panel that developed a clinical practice guideline on the diagnosis of HP for the American Thoracic Society, Japanese Respiratory Society, and Asociación Latinoamericana del Tórax. MEDLINE, the Cochrane Library, and EMBASE were searched from January 1946 to October 2019 for studies that used a questionnaire or serum IgG testing to identify exposures that may have caused HP. The Grading of Recommendations, Assessment, Development, and Evaluation approach was used to appraise the quality of the evidence.Results: Searches identified 1,141 and 926 potentially relevant articles for questionnaires and serum IgG testing, respectively. The full texts of 32 and 49 articles, respectively, were reviewed. Two observational studies for questionnaires and 15 accuracy studies for serum IgG testing were selected. Questionnaires were better at detecting potentially relevant exposures than clinical history (100% vs. 26%; risk ratio [RR], 3.80; 95% confidence interval [95% CI], 1.79-8.06) and serum IgG testing (100% vs. 63%; RR, 1.58; 95% CI, 1.12-2.23) but did not differ from serum IgG testing plus bronchial challenge testing (59% vs. 65%; RR, 0.90; 95% CI, 0.65-1.24). Longer, detailed questionnaires were more likely to lead to identification of potential exposures. Only 70% of potential exposures identified by questionnaires were subsequently confirmed by environmental testing. Serum IgG testing distinguished HP from healthy exposed and unexposed control subjects with high sensitivity (90% and 92%, respectively) and high specificity (91% and 100%, respectively) but did not distinguish HP as effectively from interstitial lung diseases (ILDs; sensitivity of 83% and specificity of 68%).Conclusions: Using a questionnaire may help clinicians identify potentially relevant exposures when evaluating a patient with newly identified ILD for HP. Serum IgG testing may also lead to identification of potentially relevant exposures, but its usefulness for distinguishing HP from other types of ILD is poor.

The pulmonary nodule following lung transplantation.

The clinical scenario of a pulmonary nodule following lung transplantation is one with limited experience and no supporting guidelines for the approach to diagnosis and management. Given the broad differential diagnosis for pulmonary nodules in this setting, most of which are life-threatening without appropriate treatment, aggressive evaluation is required. Here we present a case of a 70-year-old female with the development of a large pulmonary nodule in the native lung four years following a single lung transplant. She underwent bronchoscopy with endobronchial ultrasound to achieve a tissue diagnosis which showed small cell lung carcinoma. The patient was started on chemotherapy and has shown clinical and radiographic improvement at most recent follow up seven months after the initial diagnosis. In this report we discuss the differential diagnosis and corresponding imaging findings for the pulmonary nodule following lung transplantation to aid in guiding clinicians navigate this challenging clinical situation.

Transbronchial Biopsy and Cryobiopsy in the Diagnosis of Hypersensitivity Pneumonitis among Patients with Interstitial Lung Disease.

Rationale: Hypersensitivity pneumonitis (HP) is an interstitial lung disease (ILD) with a diagnosis based on clinical, radiological, and pathological findings. The evidence supporting transbronchial forceps lung biopsy (TBBx) and transbronchial lung cryobiopsy (TBLC) as sampling techniques to diagnose HP in patients with newly detected ILD has not been reviewed systematically.Objectives: A systematic review was performed to assess the diagnostic yield and complication rates of TBBx or TBLC in patients with newly detected ILD whose differential diagnosis includes HP and to inform the development of the American Thoracic Society, Japanese Respiratory Society, and Asociación Latinoamericana del Tórax clinical practice guidelines on the diagnosis of HP.Methods: Medline, Excerpta Medica Database, and the Cochrane Library were searched through October 2019. Studies that enrolled patients with ILD and reported the diagnostic yield of TBBx or TBLC were selected for inclusion. Data related to diagnostic yield and safety outcomes were extracted and then pooled across studies via meta-analysis. The quality of the evidence was appraised using the grading of recommendations, assessment, development, and evaluation (GRADE) approach.Results: The histopathologic diagnostic yields (number of procedures that yielded a histopathologic diagnosis divided by the total number of procedures performed) of TBBx and TBLC were 37% (95% confidence interval [CI], 32-42%) and 82% (95% CI, 78-86%), respectively, among patients with ILD. Among those diagnosed by TBBx, the proportion with HP could not be determined. However, among those diagnosed by TBLC, 13.4% had HP. TBBx was complicated by moderate to severe bleeding, severe bleeding, and pneumothorax in 4% (95% CI, 0-8%), 0% (95% CI, 0-1%), and 7% (95% CI, 2-13%) of patients, respectively. TBLC was complicated by any bleeding, severe bleeding, and pneumothorax in 11% (95% CI, 7-15%), 0% (95% CI, 0-1%), and 11% (95% CI, 9-14%) of patients, respectively. The quality of the evidence was very low because of the uncontrolled study designs, lack of consecutive enrollment, and inconsistent results.Conclusions: Very low-quality evidence indicated that TBLC had a higher diagnostic yield than TBBx among patients with ILD, although complications were similar.

Management of tracheo-oesophageal fistula in adults.

Tracheo-oesophageal fistula (TOF) is a pathological connection between the trachea and the oesophagus that is associated with various underlying conditions including malignancies, infections, inhalation injuries and traumatic damage. As the condition spans multiple organ systems with varying aetiologies and acuities, TOF poses unique diagnostic and management challenges to pulmonologists, gastroenterologists and thoracic surgeons alike. Although stents have been a cornerstone in the management of TOF, there exists a large gap in our understanding of their efficacy and precise methodology, making stenting procedure both art and science. TOFs relating to underlying oesophageal or tracheal malignancies require advanced understanding of the airway and digestive tract anatomy, dimensions of the fistula, stent characteristics and types, and the interplay between the oesophageal stent and the airway stent if dual stenting procedure is elected. In this review article, we review the most up-to-date data on risk factors, clinical manifestations, diagnostic approaches, management methods and prognosis. Consequently, this article serves to evaluate current therapeutic strategies and the future directions in the areas of 3D-printed stents, over-the-scope clipping systems, tissue matrices and atrial septal closure devices.

Bronchoalveolar Lavage Lymphocytes in the Diagnosis of Hypersensitivity Pneumonitis among Patients with Interstitial Lung Disease.

Rationale: Hypersensitivity pneumonitis (HP) is an interstitial lung disease (ILD) characterized by inflammation and/or fibrosis in response to an inhalational exposure.Objectives: To determine the value of bronchoalveolar lavage (BAL) fluid lymphocyte cellular analysis in the detection of HP among patients with newly detected ILD.Methods: This systematic review was undertaken in the context of development of an American Thoracic Society, Japanese Respiratory Society, and Asociación Latinoamericana del Tórax clinical practice guideline. The clinical question was, "should patients with newly detected ILD undergo BAL fluid lymphocyte analysis to diagnose HP?" MEDLINE, EMBASE, and the gray literature were searched through October 2019. Studies that reported the percentage of BAL fluid lymphocytes for various ILDs were selected for inclusion. Meta-analyses compared the mean percentage of BAL fluid lymphocytes among patients with HP with that among patients with idiopathic pulmonary fibrosis (IPF) or sarcoidosis. The sensitivity and specificity by which various percentages of BAL fluid lymphocytes distinguish HP from IPF and sarcoidosis were also evaluated.Results: Eighty-four articles were selected. No randomized trials or observational studies were identified that compared BAL fluid lymphocyte analysis with no BAL fluid lymphocyte analysis in patients with ILD. Included studies were case series describing BAL fluid cell differentials in patients with various ILDs. The percentage of BAL fluid lymphocytes was significantly higher in both fibrotic and nonfibrotic HP compared with IPF. Similarly, the percentage of BAL fluid lymphocytes was significantly higher in both fibrotic and nonfibrotic HP compared with sarcoidosis. A threshold of 20% BAL fluid lymphocytes distinguished fibrotic HP from IPF with a sensitivity and specificity of 69% and 61%, respectively, and nonfibrotic HP from IPF with a sensitivity and specificity of 95% and 61%, respectively. It distinguished fibrotic HP from sarcoidosis with a sensitivity and specificity of 69% and 26%, respectively, and nonfibrotic HP from sarcoidosis with a sensitivity and specificity of 95% and 26%, respectively.Conclusions: The percentage of BAL fluid lymphocytes is higher in HP than IPF or sarcoidosis. However, a threshold that distinguishes HP from IPF or sarcoidosis with both high sensitivity and high specificity was not identified.

Diagnosis of Hypersensitivity Pneumonitis in Adults. An Official ATS/JRS/ALAT Clinical Practice Guideline.

Background: This guideline addresses the diagnosis of hypersensitivity pneumonitis (HP). It represents a collaborative effort among the American Thoracic Society, Japanese Respiratory Society, and Asociación Latinoamericana del Tórax.Methods: Systematic reviews were performed for six questions. The evidence was discussed, and then recommendations were formulated by a multidisciplinary committee of experts in the field of interstitial lung disease and HP using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach.Results: The guideline committee defined HP, and clinical, radiographic, and pathological features were described. HP was classified into nonfibrotic and fibrotic phenotypes. There was limited evidence that was directly applicable to all questions. The need for a thorough history and a validated questionnaire to identify potential exposures was agreed on. Serum IgG testing against potential antigens associated with HP was suggested to identify potential exposures. For patients with nonfibrotic HP, a recommendation was made in favor of obtaining bronchoalveolar lavage (BAL) fluid for lymphocyte cellular analysis, and suggestions for transbronchial lung biopsy and surgical lung biopsy were also made. For patients with fibrotic HP, suggestions were made in favor of obtaining BAL for lymphocyte cellular analysis, transbronchial lung cryobiopsy, and surgical lung biopsy. Diagnostic criteria were established, and a diagnostic algorithm was created by expert consensus. Knowledge gaps were identified as future research directions.Conclusions: The guideline committee developed a systematic approach to the diagnosis of HP. The approach should be reevaluated as new evidence accumulates.

Use of Tracheostomy During the COVID-19 Pandemic: American College of Chest Physicians/American Association for Bronchology and Interventional Pulmonology/Association of Interventional Pulmonology Program Directors Expert Panel Report.

BACKGROUND: The role of tracheostomy during the coronavirus disease 2019 (COVID-19) pandemic remains unknown. The goal of this consensus statement is to examine the current evidence for performing tracheostomy in patients with respiratory failure from COVID-19 and offer guidance to physicians on the preparation, timing, and technique while minimizing the risk of infection to health care workers (HCWs). METHODS: A panel including intensivists and interventional pulmonologists from three professional societies representing 13 institutions with experience in managing patients with COVID-19 across a spectrum of health-care environments developed key clinical questions addressing specific topics on tracheostomy in COVID-19. A systematic review of the literature and an established modified Delphi consensus methodology were applied to provide a reliable evidence-based consensus statement and expert panel report. RESULTS: Eight key questions, corresponding to 14 decision points, were rated by the panel. The results were aggregated, resulting in eight main recommendations and five additional remarks intended to guide health-care providers in the decision-making process pertinent to tracheostomy in patients with COVID-19-related respiratory failure. CONCLUSION: This panel suggests performing tracheostomy in patients expected to require prolonged mechanical ventilation. A specific timing of tracheostomy cannot be recommended. There is no evidence for routine repeat reverse transcription polymerase chain reaction testing in patients with confirmed COVID-19 evaluated for tracheostomy. To reduce the risk of infection in HCWs, we recommend performing the procedure using techniques that minimize aerosolization while wearing enhanced personal protective equipment. The recommendations presented in this statement may change as more experience is gained during this pandemic.

Tracheal tumors.

PURPOSE OF REVIEW: This article provides the most recent literature and experienced guidance about diagnosis and management of tracheal tumors, including future directions. RECENT FINDINGS: Tracheal tumors are challenging to diagnose given their nonspecific and late-onset symptoms. Critical airway obstruction is the most feared complication. The cornerstone in management of them is surgical resection whenever is possible. Different diagnostic tests (i.e., imaging and bronchoscopy) help in the assessment of resectability. Alternative management including interventional bronchoscopic techniques can be offered to patients who are not suitable for surgical resection. Radiation and chemotherapy can also be used as adjuvant, neoadjuvant or sole treatment in malignant tumors. Recent advances in tracheal transplantation and bioengineering with tracheal reconstruction have shown a new direction in the management of these tumors. All these topics will be discussed in this article. SUMMARY: Despite advances in diagnostic and therapeutic techniques, tracheal tumors are still a medical challenge. Although studies are still trying to find the best surgical techniques as well as the role for chemotherapy and radiation, most recent studies are addressing tracheal reconstruction and transplantation as the new horizon for management.

Risk factors for pleural effusion recurrence in patients with malignancy.

BACKGROUND AND OBJECTIVE: The main purpose of treatment in patients with malignant pleural effusion (MPE) is symptom palliation. Currently, patients undergo repeat thoracenteses prior to receiving a definitive procedure as clinicians are not aware of the risk factors associated with fluid recurrence. The primary objective of this study was to identify risk factors associated with recurrent symptomatic MPE. METHODS: Retrospective multicentre cohort study of patients who underwent first thoracentesis was performed. The primary outcome was time to fluid recurrence requiring intervention in patients with evidence of metastatic disease. We used a cause-specific hazard model to identify risk factors associated with fluid recurrence. We also developed a predictive model, utilizing Fine-Gray subdistribution hazard model, and externally validated the model. RESULTS: A total of 988 patients with diagnosed metastatic disease were included. Cumulative incidence of recurrence was high with 30% of patients recurring by day 15. On multivariate analysis, size of the effusion on chest X-ray (up to the top of the cardiac silhouette (hazard ratio (HR): 1.84, 95% CI: 1.21-2.80, P = 0.004) and above the cardiac silhouette (HR: 2.22, 95% CI: 1.43-3.46, P = 0.0004)), larger amount of pleural fluid drained (HR: 1.06, 95% CI: 1.04-1.07, P < 0.0001) and higher pleural fluid LDH (HR: 1.008, 95% CI: 1.004-1.011, P < 0.0001) were associated with increased hazard of recurrence. Negative cytology (HR: 0.52, 95% CI: 0.43-0.64, P < 0.0001) was associated with decreased hazard of recurrence. The model had low prediction accuracy. CONCLUSION: Pleural effusion size, amount of pleural fluid drained, LDH and pleural fluid cytology were found to be risk factors for recurrence.

Emergent airway management in a patient with in situ tracheal stent: A lesson learned.

The prevalence of in situ tracheal stents has increased in the past two decades for the management of malignant and benign central airway diseases for either palliation or definitive therapy. Recent placement of a tracheal stent has been associated with edema of the upper airway; therefore, these patients are at a great risk for airway collapse, especially within the days most recent to the procedure. The authors present the case of a morbidly obese patient with a tracheal stent admitted to the Intensive Care Unit who developed acute respiratory failure and was found to be "unable to ventilate, unable to intubate." Surgical airway approach through a cricothyroidotomy failed to provide a patent airway and the patient subsequently developed cardiac arrest and expired. The presence of tracheal stent poses a high challenge during emergent airway interventions; thus, carefully planned airway manipulation in such patients is paramount in order to avoid catastrophic outcomes.

Rigid Bronchoscopy.

Rigid bronchoscopy is one of the oldest medical techniques used in the respiratory and thoracic fields. Even though its use declined after the development of flexible bronchoscopy, it has again gained importance with the growth of interventional pulmonology, becoming a critical technique taught as part of the training in this subspecialty. The therapeutic advantages compared to other approaches of thoracic pathologies makes rigid bronchoscopy a primary component in the present and future of interventional pulmonary medicine.

A Prediction Model to Help with the Assessment of Adenopathy in Lung Cancer: HAL.

RATIONALE: Estimating the probability of finding N2 or N3 (prN2/3) malignant nodal disease on endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in patients with non-small cell lung cancer (NSCLC) can facilitate the selection of subsequent management strategies. OBJECTIVES: To develop a clinical prediction model for estimating the prN2/3. METHODS: We used the AQuIRE (American College of Chest Physicians Quality Improvement Registry, Evaluation, and Education) registry to identify patients with NSCLC with clinical radiographic stage T1-3, N0-3, M0 disease that had EBUS-TBNA for staging. The dependent variable was the presence of N2 or N3 disease (vs. N0 or N1) as assessed by EBUS-TBNA. Univariate followed by multivariable logistic regression analysis was used to develop a parsimonious clinical prediction model to estimate prN2/3. External validation was performed using data from three other hospitals. MEASUREMENTS AND MAIN RESULTS: The model derivation cohort (n = 633) had a 25% prevalence of malignant N2 or N3 disease. Younger age, central location, adenocarcinoma histology, and higher positron emission tomography-computed tomography N stage were associated with a higher prN2/3. Area under the receiver operating characteristic curve was 0.85 (95% confidence interval, 0.82-0.89), model fit was acceptable (Hosmer-Lemeshow, P = 0.62; Brier score, 0.125). We externally validated the model in 722 patients. Area under the receiver operating characteristic curve was 0.88 (95% confidence interval, 0.85-0.90). Calibration using the general calibration model method resulted in acceptable goodness of fit (Hosmer-Lemeshow test, P = 0.54; Brier score, 0.132). CONCLUSIONS: Our prediction rule can be used to estimate prN2/3 in patients with NSCLC. The model has the potential to facilitate clinical decision making in the staging of NSCLC.