Mobile cone-beam computed tomography complementing shape-sensing robotic-assisted bronchoscopy in the small pulmonary nodule sampling: A multicentre experience.

BACKGROUND AND OBJECTIVE: Shape-sensing robotic-assisted bronchoscopy (ssRAB) has expanded as an important diagnostic tool for peripheral pulmonary nodules (PPNs), with diagnostic yields ranging from 60% to 88%. However, sampling and diagnosing PPN less than 2 cm in size has historically been challenging. Mobile cone-beam computed tomography (mCBCT) has been recently integrated into ssRAB to improve diagnostic accuracy, but its added value remains uncertain. We aim to describe the role of mCBCT and determine if it provides any diagnostic advantage. METHODS: A multicentre, retrospective study on the use of ssRAB and mCBCT in two tertiary care institutions: Mayo Clinic Florida and Massachusetts General Hospital. The primary outcome was diagnostic yield and sensitivity for malignancy of ssRAB complemented with mCBCT, compared to ssRAB with the standard 2D fluoroscopy. RESULTS: A total of 192 nodules were biopsied from 173 patients. mCBCT was used in 117 (60.9%) nodules. The overall diagnostic yield was 85.4%. Diagnostic yield between subgroups with and without mCBCT was 83.8% and 88% (p = 0.417), respectively. The mCBCT group had fewer solid nodules (65.8% vs. 81.3%, p = 0.020) and a higher number of ground-glass nodules (10.3% vs. 1.3%, p = 0.016). CONCLUSION: Overall, diagnostic yield between subgroups with and without mCBCT was similar. The complementary use of mCBCT to ssRAB allows proceduralists to target more complex and subsolid PPNs with a diagnostic yield comparable to simple solid PPNs while maintaining an excellent safety profile.

Robotic bronchoscopy and future directions of interventional pulmonology.

PURPOSE OF REVIEW: To describe the emerging field of robotic bronchoscopy within advanced diagnostic bronchoscopy. We review the literature available for these two novel platforms to highlight their differences and discuss the impact on future directions. RECENT FINDINGS: There are two distinct technologies both known as robotic bronchoscopy. The Monarch robotic-assisted bronchoscopy is based on electromagnetic guidance whereas the Ion robotic-assisted bronchoscopy is founded on shape sensing technology. Although there is ongoing work to explore the capabilities of these systems, studies have shown that both are safe modalities. Furthermore, both hold promise to improve diagnostic yield and may eventually pave the way for therapeutic bronchoscopic ablation in the future. SUMMARY: Although both platforms fall under the umbrella term of robotic-assisted bronchoscopy, the Monarch and Ion systems are quite unique in their technology. Thus far, both have demonstrated safety, and early data shows promising results for improved diagnostic yield compared to previously advanced bronchoscopy modalities, especially when combined with advanced confirmatory imaging. Future directions may include bronchoscopic ablation of peripheral lesions given the stability and reach of these platforms.

Therapeutic Bronchoscopy for Lung Nodules: Where Are We Now?

Lobar resection has been the established standard of care for peripheral early-stage non-small cell lung cancer (NSCLC). Over the last few years, surgical lung sparing approach (sublobar resection [SLR]) has been compared with lobar resection in T1N0 NSCLC. Three nonsurgical options are available in those patients who have a prohibitive surgical risk, and those who refuse surgery: stereotactic body radiotherapy (SBRT), percutaneous ablation, and bronchoscopic ablation. Local ablation involves placement of a probe into a tumor, and subsequent application of either heat or cold energy, pulsing electrical fields, or placement of radioactive source under an image guidance to create a zone of cell death that encompasses the targeted lesion and an ablation margin. Despite being in their infancy, the bronchoscopic ablative techniques are undergoing rapid research, as they extrapolate a significant knowledge-base from the percutaneous techniques that have been in the radiologist's armamentarium since 2000. Here, we discuss selected endoscopic and percutaneous thermal and non-thermal therapies with the focus on their efficacy and safety.

Microwave Ablation for Malignant Central Airway Obstruction: A Pilot Study.

BACKGROUND: Malignant central airway obstruction (CAO) is a debilitating complication of primary lung cancer and pulmonary metastases. Therapeutic bronchoscopy is used to palliate symptoms and/or bridge to further therapy. Microwave ablation (MWA) heats tissue by creating an electromagnetic field around an ablation device. We present a pilot study utilizing endobronchial MWA via flexible bronchoscopy as a novel modality for the management of malignant CAO. METHODS: Therapeutic bronchoscopy with a flexible MWA probe was performed in 8 cases. We reviewed tumor size, previous ablative techniques, number of applications, ablation time, amount of energy delivered, rate of successful recanalization, complications, and 30-day follow-up. RESULTS: Successful airway recanalization was achieved in all cases. No complications were noted. In 1 case, tumor in-growth within a silicone stent was ablated with no damage to the stent. DISCUSSION: Endobronchial MWA is a novel technique for tumor destruction while maintaining an airway axis. The oven effect and air gap around a tumor allow for safe and effective tissue devitalization and hemostasis without a thermal effect on structures surrounding the airway.

Novel Robotic-Assisted Cryobiopsy for Peripheral Pulmonary Lesions.

PURPOSE: Tissue acquisition in lung cancer is vital for multiple reasons. Primary reasons reported for molecular testing failure in lung cancer biopsy specimens include insufficient amount of tumor cells provided and inadequate tissue quality. Robotic bronchoscopy is a new tool enabling peripheral pulmonary lesion sampling; however, diagnostic yield remains imperfect possibly due to the location of nodules adjacent to or outside of the airway. The 1.1-mm cryoprobe is a novel diagnostic tool and accesses tissue in a 360-degree manner, thus potentially sampling eccentric/adjacent lesions. This study examines the diagnostic yield of the cryoprobe compared to standard needle aspiration and forceps biopsy. It additionally evaluates yield for molecular markers in cases of lung cancer. METHODS: This is a retrospective analysis of 112 patients with 120 peripheral pulmonary lesions biopsied via robotic bronchoscopy using needle aspirate, forceps, and cryobiopsy. RESULTS: The overall diagnostic yield was 90%. Nearly 18% of diagnoses were made exclusively from the cryobiopsy sample. Molecular analysis was adequate on all cryobiopsy samples sent. Digital imaging software confirmed an increase in quantity and quality of samples taken via cryobiopsy compared to needle aspirate and traditional forceps biopsy. CONCLUSION: Using the 1.1-mm cryoprobe to biopsy PPN combined with the Ion robotic bronchoscopy system is safe, feasible, and provides more diagnostic tissue than needle aspirates or traditional forceps biopsies. The combination of cryobiopsy with robotic-assisted bronchoscopy increased diagnostic yield, likely due to its 360-degree tissue acquisition which is beneficial when targeting extraluminal lesions adjacent to the airway.

Combined Percutaneous Tracheostomy and Endoscopic Gastrostomy Tubes in COVID-19: A Prospective Series of Patient Outcomes.

Background: A significant number of patients with severe respiratory failure related to COVID-19 require prolonged mechanical ventilation. Minimal data exists regarding the timing, safety, and efficacy of combined bedside percutaneous tracheostomy and endoscopy gastrostomy tube placement in these patients. The safety for healthcare providers is also in question. This study's objective was to evaluate the effectiveness and safety of combined bedside tracheostomy and gastrostomy tube placement in COVID-19 patients. Design and Methods: This is a single arm, prospective cohort study in patients with COVID-19 and acute respiratory failure requiring prolonged mechanical ventilation who underwent bedside tracheostomy and percutaneous endoscopic gastrostomy placement. Detailed clinical and procedural data were collected. Descriptive statistics were employed and time to event curves were estimated and plotted using the Kaplan Meier method for clinically relevant prespecified endpoints. Results: Among 58 patients, the median total intensive care unit (ICU) length of stay was 29 days (24.7-33.3) with a median of 10 days (6.3-13.7) postprocedure. Nearly 88% of patients were weaned from mechanical ventilation postprocedure at a median of 9 days (6-12); 94% of these were decannulated. Sixty-day mortality was 10.3%. Almost 90% of patients were discharged alive from the hospital. All procedures were done at bedside with no patient transfer required out of the ICU. A median of 3.0 healthcare personnel total were present in the room per procedure. Conclusion: This study shows that survival of critically ill COVID-19 patients after tracheostomy and gastrostomy was nearly 90%. The time-to-event curves are encouraging regarding time to weaning, downsizing, decannulation, and discharge. A combined procedure minimizes the risk of virus transmission to healthcare providers in addition to decreasing the number of anesthetic episodes, transfusions, and transfers patients must undergo. This approach should be considered in critically ill COVID-19 patients requiring prolonged mechanical ventilation.

Argon Plasma Coagulation: Elucidation of the Mechanism of Gas Embolism.

BACKGROUND: Argon plasma coagulation (APC) is a tool used in the management of tracheobronchial obstruction or bleeding. Complications include gas embolism which can cause devastating effects including hemodynamic instability, cardiac arrest, and stroke. Multiple theories as to how gas embolism occurs with APC have been postulated; however, none have identified the exact mechanism. OBJECTIVES: To identify the mechanism by which APC causes gas embolism in the tracheobronchial tree. METHODS: Using an explanted porcine tracheobronchial tree with lung parenchyma, the APC catheter was applied through noncontact and direct contact to the endobronchial airway mucosa via flexible bronchoscopy. This was done at multiple gas flow settings and pulse durations. Visual changes in the mucosa were photographed, videoed, and described. RESULTS: Gross evidence of submucosal gas transfer occurred when the APC catheter was in direct contact with the mucosa at all gas flow settings in all applications, despite using shorter pulse durations. Whenever the catheter was not in contact with the mucosa, there was no transfer of gas at any gas flow setting or pulse duration. CONCLUSIONS: Direct mucosal contact with the APC probe leads to submucosal gas deposition and is a likely mechanism for gas entry into the intravascular space. In reported cases of APC-associated gas embolism, presence of a vascularized endobronchial tumor may have increased the risk of gas tracking into the intravascular space. Care should be taken when applying APC during brisk bleeding or limited vision, as inadvertent mucosal contact may occur and could increase the risk of gas embolism.

Pre-Procedural COVID-19 Nasopharyngeal Swab Has Good Concordance with Bronchoalveolar Lavage in Patients at Low Risk for Viral Infection.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has drastically affected hospital and operating room (OR) workflow around the world as well as trainee education. Many institutions have instituted mandatory preoperative SARS-CoV-2 PCR nasopharyngeal swab (NS) testing in patients who are low risk for COVID-19 prior to elective cases. This method, however, is challenging as the sensitivity, specificity, and overall reliability of testing remains unclear. OBJECTIVES: The objective of this study was to assess the concordance of a negative NS in low risk preoperative patients with lower airway bronchoalveolar lavage (BAL) specimens obtained from the same patients. METHODS: We prospectively sent intraoperative lower airway BAL samples collected within 48 h of a negative mandatory preoperative NS for SARS-CoV-2 PCR testing. All adult patients undergoing a scheduled bronchoscopic procedure for any reason were enrolled, including elective and nonelective cases. RESULTS: One-hundred eighty-nine patients were included. All BAL specimens were negative for SARS-CoV-2 indicative of 100% concordance between testing modalities. CONCLUSIONS: These results are promising and suggest that preoperative nasopharyngeal SARS-CoV-2 testing provides adequate screening to rule out active COVID-19 infection prior to OR cases in a population characterized as low risk by negative symptom screening. This information can be used for both pre-procedural screening and when reintroducing trainees into the workforce.

Management of Significant Airway Bleeding during Robotic Assisted Bronchoscopy: A Tailored Approach.

Robotic assisted bronchoscopy represents a major turning point in bronchoscopic history. The management strategies to address significant airway bleeding in this "robotic era" are not well documented, and further guidance is required. We present a case report that exemplifies our approach and management strategy using a combined and simultaneous flexible/robotic bronchoscopy if this complication is encountered.

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.

Treatment of Recurrent Respiratory Papillomatosis: Case Series and Review of Technique.

Adult Recurrent Respiratory Papillomatosis (RRP) is a rare disease caused by the human papilloma virus in which papilloma grows from the respiratory epithelium. Patients can suffer from significant respiratory distress secondary to tracheal or bronchial obstruction by papilloma and the mainstay of treatment is bronchoscopic debridement. There are a variety of techniques to resect the endoluminal tumor, including CO2 or YAG laser, argon plasma coagulation, microdebrider and cold forceps. There have been documented cases of healthcare workers contracting HPV after exposure to surgical smoke during ablation of papilloma and measures should be taken to avoid inhalation of the smoke plume. For proximal lesions that are accessible to a microdebrider, this appears to be a safe and effective technique that does not generate heat or surgical smoke. The rate of recurrence of adult-onset respiratory papilloma after initial debulking varies and adjuvant medical therapy including intralesional cidofovir, interferon, or oral indole-3-carbinol has been used to slow recurrence. Malignant transformation of adult-onset RRP to squamous cell carcinoma has been reported to occur in 3-7% of cases. Therefore, ongoing surveillance is needed to monitor for disease progression and malignant transformation. Here we describe three patients whose tracheal disease was managed with an Nd-YAG laser and microdebrider. One patient was treated with adjuvant systemic indole-3 carbinol and another was maintained with serial debridement only. The third patient presented with obstructing squamous cell carcinoma of the trachea and was treated with definitive chemoradiation. She presented with a new left mainstem lesion 6 months later which was diagnosed as RRP. She was started on indole-3 carbinol, but unfortunately it transformed to squamous cell carcinoma 8 months later.

Bronchoscope-Guided Percutaneous Endoscopic Gastrostomy Tube Placement by Interventional Pulmonologists: A Feasibility and Safety Study.

BACKGROUND: Percutaneous endoscopic gastrostomy (PEG) tube placement is a procedure frequently done in the intensive care unit. The use of a traditional endoscope can be difficult in cases of esophageal stenosis and theoretically confers an increased risk of infection due to its complex architecture. We describe a technique using the bronchoscope, which allows navigation through stenotic esophageal lesions and also minimizes the risk of endoscopy-associated infections. METHODS: Prospective series of patients who had PEG tube placement guided by a bronchoscope. Procedural outcomes including successful placement, duration of the entire procedure, time needed for passage of the bronchoscope from the oropharynx to the major curvature, PEG tube removal rate, and mortality were collected. Procedural adverse events, including infections and long-term PEG-related complications, were recorded. RESULTS: A total of 84 patients underwent bronchoscope-guided PEG tube placement. Percutaneous endoscopic gastrostomy tube insertion was completed successfully in 82 (97.6%) patients. Percutaneous endoscopic gastrostomy tube placement was performed immediately following percutaneous tracheostomy in 82.1%. Thirty-day mortality and 1-year mortality were 11.9% and 31%, respectively. Overall, minor complications occurred in 2.4% of patients, while there were no major complications. No serious infectious complications were identified and no endoscope-associated hospital acquired infections were documented. CONCLUSIONS: The use of the bronchoscope can be safely and effectively used for PEG tube placement. The use of bronchoscope rather than a gastroscope has several advantages, which include the ease of navigating through complex aerodigestive disorders such as strictures and fistulas as well as decreased health-care utilization. In addition, it may have a theoretical advantage of minimizing infections related to complex endoscopes.

Efficacy of the Spiration Valve System in Patients with Severe Heterogeneous Emphysema: A Systematic Review and Meta-Analysis.

BACKGROUND: Spiration Valve System (SVS) is an alternative for patients with severe heterogeneous emphysema; however, data about efficacy from randomized controlled trials (RCT) are unclear. OBJECTIVES: To explore both efficacy and safety of SVS in patients with severe emphysema and hyperinflation. METHODS: We included PubMed, EMBASE, Coch-rane database. All searches were performed until August 2019. Only RCTs were included for analysis. Risk of bias was assessed using Cochrane risk of bias tool. A meta-analysis evaluated change in forced expiratory volume in 1 s (FEV1), 6-min walking test (6MWT), residual volume, modified medical research council (mMRC) and Saint George respiratory questionnaire (SGRQ), all-cause mortality, risk of pneumothorax, and risk of acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Quality of the evidence was rated using GRADE approach. RESULTS: Four RCTs including 629 subjects were included. SVS showed an overall change of 0.03 L (-0.07 to 0.13, I2 = 90%) in the in FEV1 (L) and a 2.03% (-2.50 to 6.57, I2 = 96%) in the predicted FEV1 (%) compared to baseline; however, studies without collateral ventilation (CV) showed an improvement of 0.12 L (95% CI 0.09-0.015, I2 = 0%), This subgroup also reported better results in SGRQ -12.27 points (95% CI -15.84 to -8.70, I2 = 0%) and mMRC -0.54 (95% CI -0.74 to -0.33, I2 = 0%). We found no benefit in 6MWT mean difference = 4.56 m (95% CI -21.88 to 31.00, I2 = 73%). Relative risk of mortality was 2.54 (95% CI 0.81-7.96, I2 = 0%), for pneumothorax 3.3 (95% CI 0.61-18.12, I2 = 0%) and AECOPD 1.68 (95% CI 1.04-2.70, I2 = 0%). CONCLUSION: In patients with severe heterogeneous emphysema and hyperinflation without CV, SVS is an alternative that showed an improvement in pulmonary function, quality of life, and dyspnea score with an acceptable risk profile.

[How to interpret systematic reviews with multiple comparisons or network meta-analysis]. / Como interpretar una revisión sistemática con comparaciones múltiples o network metaanálisis.

Systematic reviews evaluating multiple interventions can be useful in different clinical situations. However, some concerns arise when more than two interventions are compared and there is a paucity of good quality randomized clinical trials. A novel statistical method based on indirect comparisons, called network meta-analysis (NMA), can be a useful approach to find a clinical answer when multiple interventions are evaluated for the same outcome or comparator. The aim of this review is to describe the main characteristics and provide a user guide for a critical analysis of NMA focusing on its three main domains, namely homogeneity, transitivity and consistency.

[Recommendations for performing interventions during the COVID-19 pandemic]. / Recomendaciones para la realización de intervenciones pulmonares durante la pandemia COVID-19.

Coronavirus infection (SARS-CoV-2), is a pandemic disease declared by the World Health Organization (WHO). This disease reports a high risk of contagion, especially by the transmission of aerosols in health care workers. In this scenario, aerosol exposure is increased in various procedures related to the airway, lungs, and pleural space. For this reason, it is important to have recommendations that reduce the risk of exposure and infection with COVID-19. In this document, a team of international specialists in interventional pulmonology elaborated a series of recommendations, based on the available evidence to define the risk stratification, diagnostic methods and technical considerations on procedures such as bronchoscopy, tracheostomy, and pleural procedures among others. As well as the precautions to reduce the risk of contagion when carrying out pulmonary interventions.

Bronchoscopic Lung Volume Reduction with Endobronchial Zephyr Valves for Severe Emphysema: A Systematic Review and Meta-Analysis.

BACKGROUND: Endoscopic lung volume reduction using Zephyr® valves has been recently adopted as a treatment option for patients with severe emphysema without collateral ventilation (CV). OBJECTIVES: To assess the efficacy and safety of Zephyr valves in such a population. METHODS: Studies were identified from MEDLINE and EMBASE databases. All searches were current until June 2018. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating the efficacy and safety of Zephyr. We defined as outcome: change in forced expiratory volume in 1 s (FEV1), in the 6-min walking test (6MWT), in the St George's Respiratory Questionnaire (SGRQ), and in residual volume (RV). Safety analysis included relative risk (RR) of pneumothorax. We assessed the quality of the evidence using GRADE. RESULTS: 7 RCTs reported on Zephyr valves and 5 RCTs included only patients without CV. Zephyr improved FEV1 with a mean difference (MD) of 17.36% (CI, 9.28-25.45, I2 = 78%). Subgroup analysis showed significant FEV1 improvement following Zephyr placement in patients with heterogeneous distribution: MD = 21.78% (CI, 8.70-34.86, I2 = 89%) and 16.27% (CI, 8.78-23.76, I2 = 0%) in patients with homogeneous emphysema. Studies with a follow-up of 3 months reported FEV1 MD = 17.19% (CI, 3.16-31.22, I2 = 89%) compared to studies with a follow-up of 6-12 months, which showed a consistent improvement of FEV1 MD = 17.90% (CI, 11.47-24.33, I2 = 0%). Zephyr also showed improvement of SGRQ, 6MWT, and RV. RR of pneumothorax was 6.32 (CI, 3.74-10.67, I2 = 0%). CONCLUSION: In this population, Zephyr valves provided significant and clinically meaningful short-term improvements in either homogeneous or heterogeneous emphysema without CV but with an increase in adverse events.

Association between inflammatory bowel disease and chronic obstructive pulmonary disease: a systematic review and meta-analysis.

INTRODUCTION: There is evidence of an association between inflammatory bowel disease (IBD) and lung conditions such as chronic obstructive pulmonary disease (COPD). This systematic review and meta-analysis explored the risk of new onset IBD in patients with COPD and new onset COPD in IBD patients. METHODS: We performed a systematic review of observational studies exploring the risk of both associations. Two independent reviewers explored the EMBASE, MEDLINE, LILACS and DOAJ databases, and the risk of bias was evaluated using the ROBBINS-I tool. Data from included studies was pooled in a random effect meta-analysis following a DerSimonian-Laird method. The quality of the evidence was ranked using GRADE criteria. RESULTS: Four studies including a pooled population of 1355 new cases were included. We found association between new onset IBD in COPD population. The risk of bias was low in most of them. Only one study reported tobacco exposure as a potential confounding factor. The pooled risk ratio (RR) for a new diagnosis of IBD in COPD patients was 2.02 (CI, 1.56 to 2.63), I2 = 72% (GRADE: low). The subgroup analyses for Crohn's disease and ulcerative colitis yielded RRs of 2.29 (CI, 1.51 to 3.48; I2 = 62%), and 1.79 (CI, 1.39 to 2.29; I2 = 19%.), respectively. DISCUSSION: According to our findings, the risk of new onset IBD was higher in populations with COPD compared to the general population without this condition. Based on our analysis, we suggest a potential association between IBD and COPD; however, further research exploring the potential effect of confounding variables, especially cigarette smoking, is still needed. REVIEW REGISTER: (PROSPERO: CRD42018096624).

[Airway tridimensional printing]. / Aplicaciones de la impresión 3D en la vía aérea central.

Tridimensional printing is becoming relevant in medicine, specially in surgical and interventional specialties. We review the technical aspects and clinical application of airway tridimensional printing. Using this technique, simulation models for bronchoscopy and models for diagnostic and therapeutic procedures such as stent design, tracheal reconstruction and airway models can be created.

Chronic obstructive pulmonary disease and lung cancer: inter-relationships.

PURPOSE OF REVIEW: Chronic obstructive pulmonary disease (COPD) is a well established risk factor for lung cancer. Newer studies reveal a myriad of other mechanisms, some proven and some putative, which may contribute to their association. RECENT FINDINGS: There is an ever-growing bundle of evidence that suggests a close association between persistent chronic inflammation and lung cancer. A few potential targets of genetic susceptibility locus for COPD and lung cancer have been suggested. Better characterization of immune dysregulation and identification of signaling pathways may assist the development of strategies to reduce risk of developing lung cancer in patients with COPD. Current lung cancer screening strategies may exclude some patients at high risk of having lung cancer. Prospective studies indicate that a screening criterion that includes variables reflecting the severity of COPD may increase the sensitivity of the screening program and reduce 'over-diagnosis bias' of indolent lung cancers. Examples of such variables include the emphysema score generated from computed tomography scans and diffusion capacity for carbon monoxide derived from lung function tests. SUMMARY: A better understanding of the inter-relationship between lung cancer pathogenesis and COPD has been described recently. Improving lung cancer screening strategies by incorporating markers of COPD severity has recently been proposed.