Screening for lung cancer: a review

Cost-Effectiveness Analyses of Lung Cancer Screening Strategies Using Low-Dose Computed Tomography: a Systematic Review

BACKGROUND

Lung cancer screening with low-dose computed tomography (LDCT) has been shown to deliver appreciable reductions in mortality in high-risk patients. However, in an era of constrained medical resources, the cost-effectiveness of such a program needs to be demonstrated.

OBJECTIVE

The aim of this study was to systematically review the literature analyzing the cost-effectiveness of lung cancer screening using LDCT.

METHODS

We searched MEDLINE, EMBASE, EBM Reviews-Health Technology Assessment, the National Health Service Economic Evaluation Database (NHS-EED), and the Cochrane Database of Systematic Reviews. Due to technological progress in CT, we limited our search to studies published between January 2000 and December 2014. Our search returned 393 unique results. After removing studies that did not meet our inclusion criteria, 13 studies remained. Costs are presented in 2014 US dollars (US$).

RESULTS

The results from the economic evaluations identified in this review were varied. All identified studies reported outcomes using either additional survival (life-years gained) or quality-adjusted life-years (QALYs gained). Results ranged from US$18,452 to US$66,480 per LYG and US$27,756 to US$243,077 per QALY gained for repeated screening. The results of cost-effectiveness analyses were sensitive to several key model parameters, including the prevalence of lung cancer, cost of LDCT for screening, the proportion of lung cancer detected as localized disease, lead time bias, and, if included, the characteristics of a smoking cessation program.

CONCLUSIONS

The cost-effectiveness of a lung cancer screening program using LDCT remains to be conclusively resolved. It is expected that its cost-effectiveness will largely depend on identifying an appropriate group of high-risk subjects.

Advances in proteomic strategies toward the early detection of lung cancer

Since the advent of the new proteomics era more than a decade ago, large-scale studies of protein profiling have been exploited to identify the distinctive molecular signatures in a wide array of biological systems spanning areas of basic biological research, various disease states, and biomarker discovery directed toward therapeutic applications. Recent advances in protein separation and identification techniques have significantly improved proteomics approaches, leading to enhancement of the depth and breadth of proteome coverage. Proteomic signatures specific for invasive lung cancer and preinvasive lesions have begun to emerge. In this review we provide a critical assessment of the state of recent advances in proteomic approaches and the biological lessons they have yielded, with specific emphasis on the discovery of biomarker signatures for the early detection of lung cancer.

Screening for lung cancer with low-dose computed tomography: a systematic review and meta-analysis of the baseline findings of randomized controlled trials

OBJECTIVES

Lung cancer is the leading cause of death among all cancers. An estimated 29% of the global population older than 15 years currently smokes tobacco. The presence of a high risk population, relatively asymptomatic nature of the disease in the early phase, and relatively good prognosis when discovered early makes screening for lung cancer an attractive proposition. We performed a systematic review and a meta-analysis of the baseline results of randomized controlled trials so far published, which included more than 14,000 patients. Analysis was used to determine whether data was for or against the screening of lung cancers using low-dose computed tomography (LDCT).

DESIGN

Random effect meta regression model of meta-analysis and systematic review.

METHODS

We performed a systematic review and a meta-analysis of the current literature to determine whether screening for lung cancer in a high-risk population with computed tomography improves outcomes. A search strategy using Medline was employed, studies selected based on preset criteria and application of exclusion criteria, and data collected and analyzed for statistical significance.

RESULTS

Screening for lung cancer using LDCT resulted in a significantly higher number of stage I lung cancers (odds ratio 3.9, 95% confidence interval [CI] 2.0-7.4), higher number of total non-small cell lung cancers (odds ratio 5.5, 95% CI 3.1-9.6), and higher total lung cancers (odds ratio 4.1, 95% CI 2.4-7.1). Screening using LDCT also resulted in increased detection of false-positive nodules (odds ratio 3.1, 95% CI 2.6-3.7) and more unnecessary thoracotomies for benign lesions (event rate 3.7 per 1000, 95% CI 3.5-3.8). For every 1000 individuals screened with LDCT for lung cancer, 9 stage I non-small cell lung cancer and 235 false-positive nodules were detected, and 4 thoracotomies for benign lesions were performed.

CONCLUSIONS

The baseline data from six randomized controlled trials offer no compelling data in favor or against the use of LDCT screening for lung cancer. We await the final results of these randomized controlled trials to improve our understanding of the effectiveness of LDCT in the screening for lung cancer and its effect on mortality.

Smoking behavior 1 year after computed tomography screening for lung cancer: Effect of physician referral for abnormal CT findings

BACKGROUND

Computed tomography (CT) lung cancer screening offers a unique clinical setting in which to promote smoking cessation. Focusing on outcomes related to the reporting of CT abnormality, we examined the natural history of smoking in the Pittsburgh Lung Screening Study.

METHODS

Pittsburgh Lung Screening Study recruited 50- to 79-year-old current and former cigarette smokers living in the Pittsburgh area. We examined self-reported smoking outcomes 1 year after study entry in a subgroup that contained 2,094 active cigarette smokers without interval lung cancer diagnosis (50.7% women; median age, 57 years; 40-year median duration of cigarette smoking; and 65.2% > or =20 cigarettes/d). Analyses compared efforts to quit in relation to physician referral for abnormal CT.

RESULTS

Since study entry, 58.5% [95% confidence interval (95% CI), 56.3-60.6%] reported any quit attempt and 27.2% (95% CI, 25.3-29.1%) reported any quit interval >30 days. One year after study entry, 15.5% (95% CI, 14.0-17.1%) reported not smoking for >30 days. Comparing persons referred because of CT abnormalities creating moderate or high lung cancer suspicion (n = 156; 7.4%) to persons not referred for any reason (n = 1145; 54.7%), propensity score-adjusted fractions with any quit attempt and with any quit interval >30 days increased 18.8% (95% CI, 11.1-26.5%) and 17.7% (95% CI, 9.4-26.0%), respectively. The fraction quit >30 days at 1 year increased 12.2% (95% CI, 4.9-19.5%).

CONCLUSIONS

Persons who experienced referral because of abnormal CT reported more smoking cessation.

Factors influencing hospital costs of lung cancer patients in Northern Ireland

Lung cancer is a major cause of morbidity and mortality. In this paper, the hospital costs incurred by 724 lung cancer patients diagnosed in 2001 were determined by review of case notes. These represented all patients diagnosed with lung cancer in Northern Ireland on whom data existed in that year. Total hospital costs in the 12 months from presentation for the 724 patients were 3.99 million pounds. Average patient costs were 5,956 pounds for patients diagnosed with non-small cell lung cancer and 5,876 pounds for those with small cell lung cancer. The main component of cost was inpatient stay, representing between 62 and 84% of costs depending on cell type. Multivariate analyses revealed significant differences in cost related to staging, co-morbidities, age, and deprivation. Total annual hospital costs were 13 times as high as the estimated enforcement cost of the smoke-free legislation in Northern Ireland.

Haptoglobin and posttranslational glycan-modified derivatives as serum biomarkers for the diagnosis of nonsmall cell lung cancer

BACKGROUND

The purpose was to evaluate the clinical utility of serum haptoglobin (Hp) and posttranslational glycan modifications of Hp for the diagnosis of nonsmall cell lung cancer (NSCLC).

METHODS

Serum proteins from patients with a new diagnosis of NSCLC and age- and sex-matched controls without cancer were compared using 2-dimensional difference gel electrophoresis (2D-DIGE). Four of the differentially expressed gel spots were identified as the beta chain of Hp. Immunoblots confirmed sialyl and fucosyl group posttranslational modifications (PTMs) of Hp. Serum enzyme-linked immunosorbent assays (ELISAs) for total Hp, sialylated Hp (SAHp), and fucosylated Hp (FHp) were designed, and levels of each were measured in an independent sample set of 74 patients. Receiver operating characteristic (ROC) analysis assessed the clinical diagnostic utility of each marker.

RESULTS

Statistically significant differences between lung cancer patients and matched controls were found by ELISA for Hp (P < .002), SAHp (P < .001), and FHp (P < .04). ROC analysis determined an area under the curve (AUC) of 0.754 for Hp, 0.740 for SAHp, and 0.794 for FHp. In addition, serum concentrations correlated with stage; Hp (r = 0.388; P = .018), SAHp (r = 0.300; P = .072), and FHp (r = 0.363; P = .027).

CONCLUSIONS

Hp and 2 of its glycoforms, SAHp and FHp, are potentially useful in the clinical diagnosis of NSCLC. The markers increase with stage, suggesting they may also be useful in stratifying patients at presentation and in following patients after treatment.

Incidental findings with cardiac CT evaluation: should we read beyond the heart?

Cardiac computed tomographic angiography (CTA) allows for simultaneous evaluation of the lung fields and associated structures. There is a debate as to the benefit of or need for routine overread of the lung fields for incidental findings. The possible improvement in cancer diagnosis with routine overreads is balanced against the major limitations of CT lung screening. Current limitations include (a) a high rate of nodule detection given that >50% of participants may have at least one noncalcified nodule; (b) the increased costs and radiation exposure associated with the resulting follow-up CT scans; (c) the cost and the morbidity of follow-up, including further testing, as well as biopsy or resection of benign noncalcified nodule (at least 25% of such procedures in several trials); (d) a small but difficult to quantify potential risk of cancer associated with multiple follow-up CT scans; and (e) a potential for increased anxiety of both the patient and the physician about nonsignificant pathology. All of these limitations are balanced against a possibility that this could lead to an earlier detection of lung cancer with the consequent improvement in the chances of the patients' survival. Extensive studies of screening CT in older smokers have revealed the prevalence of cancer to be between 0.3 and 1%. However, when applied to an ambulatory population of patients presenting for an evaluation of angina, the prevalence of lung cancer or significant non-cardiac findings may be significantly lower. We have reviewed all the relevant literature and sought to determine the potential benefits and harms of specifically overreading CTA for non-cardiac pathology. The weight of the evidence suggests that it is most prudent to not specifically reconstruct and re-read CTA scans for lung nodules. If a non-cardiac abnormality is visualized by the primary interpreter of the cardiac CT, appropriate referral or follow-up is prudent.