Screening and early detection efforts in lung cancer

Lung cancer is the leading cause of cancer-related death in the United States. Since publication of results from the National Lung Screening Trial, several professional organizations, including the US Preventive Services Task Force, have published guidelines recommending low-dose computed tomography for screening in asymptomatic, high-risk individuals. The benefits of screening include detection of cancer at an early stage when a definitive cure is possible, but the risks include overdiagnosis, false-positive results, psychological distress, and radiation exposure. The current review covers the scope of low-dose computed tomography screening, potential risks, costs, and future directions in the efforts for early detection of lung cancer.

Evaluation of the lung cancer risks at which to screen ever- and never-smokers: screening rules applied to the PLCO and NLST cohorts

BACKGROUND

Lung cancer risks at which individuals should be screened with computed tomography (CT) for lung cancer are undecided. This study's objectives are to identify a risk threshold for selecting individuals for screening, to compare its efficiency with the U.S. Preventive Services Task Force (USPSTF) criteria for identifying screenees, and to determine whether never-smokers should be screened. Lung cancer risks are compared between smokers aged 55-64 and ≥ 65-80 y.

METHODS AND FINDINGS

Applying the PLCO(m2012) model, a model based on 6-y lung cancer incidence, we identified the risk threshold above which National Lung Screening Trial (NLST, n = 53,452) CT arm lung cancer mortality rates were consistently lower than rates in the chest X-ray (CXR) arm. We evaluated the USPSTF and PLCO(m2012) risk criteria in intervention arm (CXR) smokers (n = 37,327) of the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (PLCO). The numbers of smokers selected for screening, and the sensitivities, specificities, and positive predictive values (PPVs) for identifying lung cancers were assessed. A modified model (PLCOall2014) evaluated risks in never-smokers. At PLCO(m2012) risk ≥ 0.0151, the 65th percentile of risk, the NLST CT arm mortality rates are consistently below the CXR arm's rates. The number needed to screen to prevent one lung cancer death in the 65th to 100th percentile risk group is 255 (95% CI 143 to 1,184), and in the 30th to <65th percentile risk group is 963 (95% CI 291 to -754); the number needed to screen could not be estimated in the <30th percentile risk group because of absence of lung cancer deaths. When applied to PLCO intervention arm smokers, compared to the USPSTF criteria, the PLCO(m2012) risk ≥ 0.0151 threshold selected 8.8% fewer individuals for screening (p<0.001) but identified 12.4% more lung cancers (sensitivity 80.1% [95% CI 76.8%-83.0%] versus 71.2% [95% CI 67.6%-74.6%], p<0.001), had fewer false-positives (specificity 66.2% [95% CI 65.7%-66.7%] versus 62.7% [95% CI 62.2%-63.1%], p<0.001), and had higher PPV (4.2% [95% CI 3.9%-4.6%] versus 3.4% [95% CI 3.1%-3.7%], p<0.001). In total, 26% of individuals selected for screening based on USPSTF criteria had risks below the threshold PLCO(m2012) risk ≥ 0.0151. Of PLCO former smokers with quit time >15 y, 8.5% had PLCO(m2012) risk ≥ 0.0151. None of 65,711 PLCO never-smokers had PLCO(m2012) risk ≥ 0.0151. Risks and lung cancers were significantly greater in PLCO smokers aged ≥ 65-80 y than in those aged 55-64 y. This study omitted cost-effectiveness analysis.

CONCLUSIONS

The USPSTF criteria for CT screening include some low-risk individuals and exclude some high-risk individuals. Use of the PLCO(m2012) risk ≥ 0.0151 criterion can improve screening efficiency. Currently, never-smokers should not be screened. Smokers aged ≥ 65-80 y are a high-risk group who may benefit from screening. Please see later in the article for the Editors' Summary.

Cost-effectiveness of CT screening in the National Lung Screening Trial

BACKGROUND

The National Lung Screening Trial (NLST) showed that screening with low-dose computed tomography (CT) as compared with chest radiography reduced lung-cancer mortality. We examined the cost-effectiveness of screening with low-dose CT in the NLST.

METHODS

We estimated mean life-years, quality-adjusted life-years (QALYs), costs per person, and incremental cost-effectiveness ratios (ICERs) for three alternative strategies: screening with low-dose CT, screening with radiography, and no screening. Estimations of life-years were based on the number of observed deaths that occurred during the trial and the projected survival of persons who were alive at the end of the trial. Quality adjustments were derived from a subgroup of participants who were selected to complete quality-of-life surveys. Costs were based on utilization rates and Medicare reimbursements. We also performed analyses of subgroups defined according to age, sex, smoking history, and risk of lung cancer and performed sensitivity analyses based on several assumptions.

RESULTS

As compared with no screening, screening with low-dose CT cost an additional $1,631 per person (95% confidence interval [CI], 1,557 to 1,709) and provided an additional 0.0316 life-years per person (95% CI, 0.0154 to 0.0478) and 0.0201 QALYs per person (95% CI, 0.0088 to 0.0314). The corresponding ICERs were $52,000 per life-year gained (95% CI, 34,000 to 106,000) and $81,000 per QALY gained (95% CI, 52,000 to 186,000). However, the ICERs varied widely in subgroup and sensitivity analyses.

CONCLUSIONS

We estimated that screening for lung cancer with low-dose CT would cost $81,000 per QALY gained, but we also determined that modest changes in our assumptions would greatly alter this figure. The determination of whether screening outside the trial will be cost-effective will depend on how screening is implemented. (Funded by the National Cancer Institute; NLST ClinicalTrials.gov number, NCT00047385.).

Assessing the usefulness of 18F-fluorodeoxyglucose PET-CT scan after stereotactic body radiotherapy for early-stage non-small cell lung cancer

BACKGROUND

Although stereotactic body radiation therapy (SBRT) is an established treatment option for early-stage lung cancer, there are no guidelines for reassessing patients for local treatment failure or intrathoracic recurrence after treatment. This study reports the sensitivity, specificity, and positive and negative predictive values for 18F-fluorodeoxyglucose (FDG) PET-CT scanning when used to evaluate patients after SBRT.

METHODS

Charts were reviewed of all patients who received SBRT and a subsequent FDG PET-CT scan at a university hospital over a 5-year period. Pretreatment and 3-month posttreatment tumor characteristics on PET-CT scan and outcome data (adverse events from SBRT, need for repeat biopsy, rate of local treatment failure and recurrent disease, and all-cause mortality) were recorded.

RESULTS

Eighty-eight patients were included in the study. Fourteen percent of patients (12 of 88) had positive 3-month PET scans. Of the positive results, 67% (eight of 12) were true positives. Eighty-six percent (76 of 88 patients) had negative 3-month FDG PET-CT scans, with 89% (68 of 76) true negatives. FDG PET-CT scan performed 3 months after SBRT for non-small cell lung cancer (NSCLC) had a sensitivity of 50% (95% CI, 0.26-0.75), a specificity of 94% (95% CI, 0.89-1.0), a positive predictive value of 67% (95% CI, 0.4-0.93), and a negative predictive value of 89% (95% CI, 0.83- 0.96).

CONCLUSIONS

FDG PET-CT scan 3 months after treatment of NSCLC with SBRT was a specific but insensitive test for the detection of recurrence or treatment failure. Serial CT scans should be used for early surveillance following SBRT, whereas FDG PET-CT scans should be reserved to define suspected metastatic disease or to evaluate new abnormalities on CT scan, or for possible reassessment later in the follow-up period after radiation-related inflammation subsides.

Evaluating the effect of access to free medication to quit smoking: a clinical trial testing the role of motivation

INTRODUCTION

Although the majority of smokers are ambivalent about quitting, few treatments specifically target smokers lacking motivation to quit in the near future. Most existing interventions are instead predicated on the belief that active treatments should only be distributed to smokers interested in quitting, a largely untested assumption.

METHODS

In the current clinical trial (N = 157), motivated smokers wanting to quit in the next 30 days were given a 2-week nicotine replacement therapy (NRT) sample and a referral to a quitline (Group MNQ), while unmotivated smokers were randomized to receive the same treatment (Group UNQ) or a quitline referral only (Group UQ). Participants were tracked via telephone for 3 months to assess quitting behaviors and smoking reduction.

RESULTS

Groups significantly differed across all comparisons with regard to incidence of any quit attempt (MNQ: 77%, UNQ: 40%, UQ: 18%, p < .05) and any 24-hr quit attempts (62%, 32%, 16%, p < .05). Clinically meaningful differences emerged in the rates of floating (19%, 17%, 6%) and point prevalence abstinence (17%, 15%, 5%). Compared to participants in Group UQ (11%), a greater proportion of participants in Group MNQ (48%, p = .01) and Group UNQ (31%, p = .01) reduced their daily cigarette consumption by at least half. Proxy measures of cessation readiness (e.g., motivation) favored participants receiving active forms of treatment.

CONCLUSIONS

Providing NRT samples engaged both motivated and unmotivated smokers into the quitting process and produced positive changes in smoking outcomes. This suggests that motivation should not be considered a necessary precondition to receiving treatment.

Feasibility and safety of bronchoscopic transparenchymal nodule access in canines: a new real-time image-guided approach to lung lesions

BACKGROUND

The current approaches for tissue diagnosis of a solitary pulmonary nodule are transthoracic needle aspiration, guided bronchoscopy, or surgical resection. The choice of procedure is driven by patient and radiographic factors, risks, and benefits. We describe a new approach to the diagnosis of a solitary pulmonary nodule, namely bronchoscopic transparenchymal nodule access (BTPNA).

METHODS

In anesthetized dogs, fiducial markers were placed and thoracic CT images acquired. From the CT scan, the BTPNA software provided automatic point-of-entry prescribing of a bronchoscopic path (tunnel) through parenchymal tissue directly to the lesion. The preplanned procedure was uploaded to a virtual bronchoscopic navigation system. Bronchoscopic access was performed through the tunnels created. Proximity of the distal end of the tunnel sheath to the target was measured, and safety was recorded.

RESULTS

In four canines, 13 tunnels were created. The average length of the tunnels was 32.3 mm (range, 24.7-46.7 mm). The average proximity measure was 5.7 mm (range, 0.1-12.9 mm). The distance from the pleura to the nearest point within the target was 7.4 mm (range, 0.1-15 mm). Estimated blood loss was <2 mL per case. There were no pneumothoraces.

CONCLUSIONS

We describe a new approach to accessing lesions in the lung parenchyma. BTPNA allows bronchoscopic creation of a direct path with a sheath placed in proximity to the target, creating the potential to deliver biopsy tools within a lesion to acquire tissue. The technology appears safe. Further experiments are needed to assess the diagnostic yield of this procedure in animals and, if promising, to assess this technology in humans.

The utility of nodule volume in the context of malignancy prediction for small pulmonary nodules

BACKGROUND

An estimated 150,000 pulmonary nodules are identified each year, and the number is likely to increase given the results of the National Lung Screening Trial. Decision tools are needed to help with the management of such pulmonary nodules. We examined whether adding any of three novel functions of nodule volume improves the accuracy of an existing malignancy prediction model of CT scan-detected nodules.

METHODS

Swensen's 1997 prediction model was used to estimate the probability of malignancy in CT scan-detected nodules identified from a sample of 221 patients at the Medical University of South Carolina between 2006 and 2010. Three multivariate logistic models that included a novel function of nodule volume were used to investigate the added predictive value. Several measures were used to evaluate model classification performance.

RESULTS

With use of a 0.5 cutoff associated with predicted probability, the Swensen model correctly classified 67% of nodules. The three novel models suggested that the addition of nodule volume enhances the ability to correctly predict malignancy; 83%, 88%, and 88% of subjects were correctly classified as having malignant or benign nodules, with significant net improved reclassification for each (P<.0001). All three models also performed well based on Nagelkerke R2, discrimination slope, area under the receiver operating characteristic curve, and Hosmer-Lemeshow calibration test.

CONCLUSIONS

The findings demonstrate that the addition of nodule volume to existing malignancy prediction models increases the proportion of nodules correctly classified. This enhanced tool will help clinicians to risk stratify pulmonary nodules more effectively.

Attitudes and beliefs toward lung cancer screening among US Veterans

BACKGROUND

Lung cancer (LC) is the leading cause of cancer-related death for veterans cared for by the US Veterans Health Administration. The LC burden among veterans is almost double that of the general population. Before implementation of an LC screening program, we set out to assess the role of beliefs and attitudes toward LC screening among veterans.

METHODS

Veterans presenting to the Ralph H. Johnson VA Medical Center were invited to complete a self-administered survey. The survey comprised questions about demographics, smoking status, health status, and knowledge about LC and willingness to be screened. Responses from veteran ever and never smokers were compared.

RESULTS

A total of 209 veterans completed the survey. Smokers were significantly (P &lt; .05) more likely than never smokers to be less educated, have a lower income, and report poorer health. Smokers were more likely than never smokers to have two or more comorbidities, which trended toward significance (P = .062). Smokers were more likely to have been told by a physician that they were at high risk for LC and to believe that they were at risk. Nearly all veterans surveyed (92.8%) would have a CT scan for LC screening, and 92.4% would have surgery for a screen-detected LC.

CONCLUSIONS

Veterans are overwhelmingly willing to undergo screening for LC, and it seems that participation will not be a barrier to implementation of an LC screening program. The mortality benefit of LC screening, however, may not be generalizable to the veteran population because of a higher number of comorbid conditions.

Diagnostic approach to the solitary pulmonary nodule

The number of solitary pulmonary nodules (SPNs) detected each year is expected to increase dramatically with the implementation of lung cancer screening. Although some will have radiographic features highly specific for benignity, the rest are considered indeterminate and require further investigation. The management options include continued surveillance or immediate diagnostic sampling. The decision to proceed with immediate sampling is determined by nodule characteristics (i.e., density and size), and patient risk factors and preferences. Sampling is achieved either by surgical or by nonsurgical techniques, and the choice between the two is influenced by the probability of malignancy. Surgical methods are preferred in SPNs with high probability of malignancy because they provide both a definitive diagnosis and treatment in a single procedure. In contrast, when the probability of malignancy is low to moderate nonsurgical sampling is preferred. The following is a review of the diagnostic management options available when approaching an SPN.

A review of clinical practice guidelines for lung cancer

Clinical practice guidelines are important evidence-based resources to guide complex clinical decision making. However, it is challenging for health professionals to keep abreast available guidelines and to know how and where to access relevant guidelines. This review examines currently available guidelines for lung cancer published in the English language. Important key features are listed for each identified guideline. The methodology, approaches to dissemination and implementation, and associated resources are summarised. General challenges in the area of guideline development are highlighted. The potential to collaborate more widely across lung cancer guideline developers by sharing literature searches and assessments is discussed.

Methods for staging non-small cell lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines

BACKGROUND

Correctly staging lung cancer is important because the treatment options and prognosis differ significantly by stage. Several noninvasive imaging studies and invasive tests are available. Understanding the accuracy, advantages, and disadvantages of the available methods for staging non-small cell lung cancer is critical to decision-making.

METHODS

Test accuracies for the available staging studies were updated from the second iteration of the American College of Chest Physicians Lung Cancer Guidelines. Systematic searches of the MEDLINE database were performed up to June 2012 with the inclusion of selected meta-analyses, practice guidelines, and reviews. Study designs and results are summarized in evidence tables.

RESULTS

The sensitivity and specificity of CT scanning for identifying mediastinal lymph node metastasis were approximately 55% and 81%, respectively, confirming that CT scanning has limited ability either to rule in or exclude mediastinal metastasis. For PET scanning, estimates of sensitivity and specificity for identifying mediastinal metastasis were approximately 77% and 86%, respectively. These findings demonstrate that PET scanning is more accurate than CT scanning, but tissue biopsy is still required to confirm PET scan findings. The needle techniques endobronchial ultrasound-needle aspiration, endoscopic ultrasound-needle aspiration, and combined endobronchial ultrasound/endoscopic ultrasound-needle aspiration have sensitivities of approximately 89%, 89%, and 91%, respectively. In direct comparison with surgical staging, needle techniques have emerged as the best first diagnostic tools to obtain tissue. Based on randomized controlled trials, PET or PET-CT scanning is recommended for staging and to detect unsuspected metastatic disease and avoid noncurative resections.

CONCLUSIONS

Since the last iteration of the staging guidelines, PET scanning has assumed a more prominent role both in its use prior to surgery and when evaluating for metastatic disease. Minimally invasive needle techniques to stage the mediastinum have become increasingly accepted and are the tests of first choice to confirm mediastinal disease in accessible lymph node stations. If negative, these needle techniques should be followed by surgical biopsy. All abnormal scans should be confirmed by tissue biopsy (by whatever method is available) to ensure accurate staging. Evidence suggests that more complete staging improves patient outcomes.

Activation of p53 with Nutlin-3a radiosensitizes lung cancer cells via enhancing radiation-induced premature senescence

Radiotherapy is routinely used for the treatment of lung cancer. However, the mechanisms underlying ionizing radiation (IR)-induced senescence and its role in lung cancer treatment are poorly understood. Here, we show that IR suppresses the proliferation of human non-small cell lung cancer (NSCLC) cells via an apoptosis-independent mechanism. Further investigations reveal that the anticancer effect of irradiation correlates well with IR-induced premature senescence, as evidenced by increased senescence-associated β-glactosidase (SA-β-gal) staining, decreased BrdU incorporation and elevated expression of p16(INK4a) (p16) in irradiated NSCLC cells. Mechanistic studies indicate that the induction of senescence is associated with activation of the p53-p21 pathway, and that inhibition of p53 transcriptional activity by PFT-α attenuates IR-induced tumor cell killing and senescence. Gain-of-function assays demonstrate that restoration of p53 expression sensitizes H1299 cells to irradiation, whereas knockdown of p53 expression by siRNA inhibits IR-induced senescence in H460 cells. Furthermore, treatment with Nutlin-3a, a small molecule inhibitor of MDM2, enhances IR-induced tumor cell killing and senescence by stabilizing the activation of the p53-p21 signaling pathway. Taken together, these findings demonstrate for the first time that pharmacological activation of p53 by Nutlin-3a can sensitize lung cancer cells to radiation therapy via promoting IR-induced premature senescence.

Targeting of low-dose CT screening according to the risk of lung-cancer death

BACKGROUND

In the National Lung Screening Trial (NLST), screening with low-dose computed tomography (CT) resulted in a 20% reduction in lung-cancer mortality among participants between the ages of 55 and 74 years with a minimum of 30 pack-years of smoking and no more than 15 years since quitting. It is not known whether the benefits and potential harms of such screening vary according to lung-cancer risk.

METHODS

We assessed the variation in efficacy, the number of false positive results, and the number of lung-cancer deaths prevented among 26,604 participants in the NLST who underwent low-dose CT screening, as compared with the 26,554 participants who underwent chest radiography, according to the quintile of 5-year risk of lung-cancer death (ranging from 0.15 to 0.55% in the lowest-risk group [quintile 1] to more than 2.00% in the highest-risk group [quintile 5]).

RESULTS

The number of lung-cancer deaths per 10,000 person-years that were prevented in the CT-screening group, as compared with the radiography group, increased according to risk quintile (0.2 in quintile 1, 3.5 in quintile 2, 5.1 in quintile 3, 11.0 in quintile 4, and 12.0 in quintile 5; P=0.01 for trend). Across risk quintiles, there were significant decreasing trends in the number of participants with false positive results per screening-prevented lung-cancer death (1648 in quintile 1, 181 in quintile 2, 147 in quintile 3, 64 in quintile 4, and 65 in quintile 5). The 60% of participants at highest risk for lung-cancer death (quintiles 3 through 5) accounted for 88% of the screening-prevented lung-cancer deaths and for 64% of participants with false positive results. The 20% of participants at lowest risk (quintile 1) accounted for only 1% of prevented lung-cancer deaths.

CONCLUSIONS

Screening with low-dose CT prevented the greatest number of deaths from lung cancer among participants who were at highest risk and prevented very few deaths among those at lowest risk. These findings provide empirical support for risk-based targeting of smokers for such screening. (Funded by the National Cancer Institute.).

Training for linear endobronchial ultrasound among US pulmonary/critical care fellowships: a survey of fellowship directors

BACKGROUND

Endobronchial ultrasound (EBUS) has revolutionized the ability of bronchoscopists to visualize and sample structures surrounding the tracheobronchial tree. It has been shown to be safe, minimally invasive, and highly accurate in the staging and diagnosing of mediastinal diseases. A prior survey of pulmonary fellowship program directors conducted in 2004 showed that only 2% of programs offered EBUS training.

METHODS

Surveys were mailed to 154 pulmonary/critical care fellowship directors in the United States and Puerto Rico. Demographics of the fellowship and details of EBUS training were recorded. A comparison of EBUS volume was made between programs with and without an identifiable interventional pulmonologist (IP).

RESULTS

The survey response rate was 71%. EBUS equipment was available at 89% of programs. Of those without EBUS, 100% expressed the goal of obtaining equipment within the year. An identifiable IP was present in 70% of programs. This was associated with more EBUS procedures performed by trainees ( P , .01). Only 30% of programs have a formal protocol in place to evaluate EBUS competency. Conventional transbronchial needle aspiration is routinely taught in 89% of fellowship programs.

CONCLUSIONS

EBUS exposure has rapidly disseminated into fellowship training programs, and programs with an identifiable IP are more likely to provide fellows with more EBUS procedures. The findings of this survey point out the need to develop a standardized protocol for EBUS competency that includes current recommendations and may require training with simulation.

Quality-of-life improvement and cost-effectiveness of interventional pulmonary procedures

Most interventional pulmonology studies focus on the technical success of procedures without measuring validated quality-of-life (QoL) outcomes. Studies are now incorporating end points that include QoL measurements and there are examples of interventional procedures that likely improve QoL. It is vital for the interventional pulmonary literature to incorporate cost-effectiveness when introducing new technology. While not uniformly analyzed in a rigorous manner in all studies, there are examples of interventional pulmonary studies that analyze cost-effectiveness through avoidance of more expensive procedures, cost savings per day free of emergency room visit, or cost savings per day not requiring intensive care unit care.

Variation in the efficacy of low-dose computed tomographic lung screening based on risk of lung cancer mortality in the National Lung Screening Trial

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Background: Low-dose computed tomography (LDCT) screening reduced lung cancer mortality by 20% in the National Lung Screening Trial (NLST). The efficacy of LDCT screening could be improved by targeting smokers at highest risk of lung cancer death, provided that the efficacy of LDCT screening increases with lung cancer mortality risk. Methods: We evaluated the efficacy of LDCT screening as compared to chest radiography in the NLST across groups defined by participants’ 5-year risk of lung cancer mortality at randomization, which was estimated using a validated prediction model. Across quintiles of 5-year lung cancer mortality risk [Q1: 0.15%-0.55%, Q2: 0.56%-0.84%, Q3: 0.85%-1.24%, Q4: 1.24%-2.0%, Q5: >2.0%], we estimated the number of participants with false positive screens, the number of prevented lung cancer deaths, and their ratio. Results: The number of prevented lung cancer deaths due to LDCT screening increased in tandem with lung cancer mortality risk (Q1=0.2, Q2=3.5, Q3=5.1, Q4=11.0, Q5=12.0 per 10,000 person-years; P-trend=0.01). The number of participants with false positive screens per lung cancer death prevented, a measure of screening efficiency, significantly decreased with increasing risk (Q1=1,648, Q2=181, Q3=147, Q4=64, Q5=65, P-trend<0.001). The 60% of participants at highest 5-year lung cancer mortality risk (0.85% or greater) accounted for 88% of LDCT-preventable lung cancer deaths and included only 64% of participants with a false positive screen. The 20% of participants at lowest lung cancer mortality risk (0.15%-0.55%) accounted for only 1% of LDCT-preventable lung cancer deaths. Conclusions: In the NLST, LDCT screening prevented the most lung cancer mortality among those at highest lung cancer mortality risk and prevented almost no mortality among those at lowest risk, providing empirical support for risk-based targeting of smokers to improve the efficacy of LDCT screening.

Latest advances in advanced diagnostic and therapeutic pulmonary procedures

Over the past 15 years, patients with a myriad of pulmonary conditions have been diagnosed and treated with new technologies developed for the pulmonary community. Advanced diagnostic and therapeutic procedures once performed in an operating theater under general anesthesia are now routinely performed in a bronchoscopy suite under moderate sedation with clinically meaningful improvements in outcome. With the miniaturization of scopes and instruments, improvements in optics, and creative engineers, a host of new devices has become available for clinical testing and use. A growing community of pulmonologists is doing comparative effectiveness trials that test new technologies against the current standard of care. While more research is needed, it seems reasonable to provide an overview of pulmonary procedures that are in various stages of development, testing, and practice at this time. Five areas are covered: navigational bronchoscopy, endobronchial ultrasound, endoscopic lung volume reduction, bronchial thermoplasty, and pleural procedure. Appropriate training for clinicians who wish to provide these services will become an area of intense scrutiny as new skills will need to be acquired to ensure patient safety and a good clinical result.

Invited commentary: the etiology of lung cancer in men compared with women

Lung cancer is the leading cause of cancer death among women in the United States and other Western nations. The predominant cause of lung cancer in women is active cigarette smoking. Secondhand exposure to tobacco smoke is another important cause. The hypothesis that women are more susceptible than men to smoking-induced lung cancer has not been supported by the preponderance of current data, as noted by De Matteis et al. (Am J Epidemiol. 2013;177(7):601-612) in the accompanying article. However, aspects of lung cancer in men and women continue to indicate potential male-female differences in the etiology of lung cancer, based on several observations: 1) among never smokers, women have higher lung cancer incidence rates than men; 2) there is evidence that estrogen may contribute to lung cancer risk and progression; and 3) there are different clinical characteristics of lung cancer in women compared with men, such as the higher percentage of adenocarcinomas in never smokers, the greater prevalence of epidermal growth factor receptor gene (EGFR) mutations in adenocarcinomas among never smokers, and better prognosis. Considered in total, observations such as these offer enticing clues that, even amid cigarette smoking and other commonalities in the etiology of lung cancer in men and women, distinct differences may remain to be delineated that could potentially be of scientific and clinical relevance.

Selection criteria for lung-cancer screening

BACKGROUND

The National Lung Screening Trial (NLST) used risk factors for lung cancer (e.g., ≥30 pack-years of smoking and <15 years since quitting) as selection criteria for lung-cancer screening. Use of an accurate model that incorporates additional risk factors to select persons for screening may identify more persons who have lung cancer or in whom lung cancer will develop.

METHODS

We modified the 2011 lung-cancer risk-prediction model from our Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial to ensure applicability to NLST data; risk was the probability of a diagnosis of lung cancer during the 6-year study period. We developed and validated the model (PLCO(M2012)) with data from the 80,375 persons in the PLCO control and intervention groups who had ever smoked. Discrimination (area under the receiver-operating-characteristic curve [AUC]) and calibration were assessed. In the validation data set, 14,144 of 37,332 persons (37.9%) met NLST criteria. For comparison, 14,144 highest-risk persons were considered positive (eligible for screening) according to PLCO(M2012) criteria. We compared the accuracy of PLCO(M2012) criteria with NLST criteria to detect lung cancer. Cox models were used to evaluate whether the reduction in mortality among 53,202 persons undergoing low-dose computed tomographic screening in the NLST differed according to risk.

RESULTS

The AUC was 0.803 in the development data set and 0.797 in the validation data set. As compared with NLST criteria, PLCO(M2012) criteria had improved sensitivity (83.0% vs. 71.1%, P<0.001) and positive predictive value (4.0% vs. 3.4%, P=0.01), without loss of specificity (62.9% and. 62.7%, respectively; P=0.54); 41.3% fewer lung cancers were missed. The NLST screening effect did not vary according to PLCO(M2012) risk (P=0.61 for interaction).

CONCLUSIONS

The use of the PLCO(M2012) model was more sensitive than the NLST criteria for lung-cancer detection.

Utilizing endobronchial ultrasound with fine-needle aspiration to obtain tissue for molecular analysis: a single-center experience

BACKGROUND

: Lung cancer is the leading cause of cancer deaths worldwide, with the majority of patients presenting with advanced disease for which surgery is not an option. Recently, a number of genetic mutations have been identified that predict response to chemotherapy, making the acquisition of tissue for molecular analysis important for treatment planning. It has previously been demonstrated that samples obtained using endobronchial ultrasound fine-needle aspiration (EBUS-FNA) are adequate for this analysis. This is the first report on the use of EBUS-FNA specimens for analysis of the epithelial mesenchymal transition (EMT) pathway.

METHODS

: A total of 74 consecutive patients with known or suspected lung cancer undergoing EBUS for diagnosis and/or staging were enrolled in this study. Total RNA was isolated from the FNA specimens, reverse transcribed, and analyzed for expression of a panel of genes associated with EMT using a probe-based real-time quantitative polymerase chain reaction.

RESULTS

: A total of 150 lymph nodes were sampled from the 74 patients who participated in the study. There was adequate tissue to perform real-time polymerase chain reaction in 130 (86%) of the nodes.

CONCLUSIONS

: EBUS-FNA samples are adequate for analysis of novel markers and pathways, including EMT, which may predict prognosis, responsiveness to therapy, and provide potential targets for new drug development. As the treatment of lung cancer shifts toward a more personalized approach, EBUS-FNA will likely play a central role in tissue acquisition for diagnosis, staging, and molecular analysis.