Screening for lung cancer

Impact of low-dose computed tomography (LDCT) screening on lung cancer-related mortality

BACKGROUND

Lung cancer is the most common cause of cancer-related death in the world, however lung cancer screening has not been implemented in most countries at a population level. A previous Cochrane Review found limited evidence for the effectiveness of lung cancer screening with chest radiography (CXR) or sputum cytology in reducing lung cancer-related mortality, however there has been increasing evidence supporting screening with low-dose computed tomography (LDCT).  OBJECTIVES: To determine whether screening for lung cancer using LDCT of the chest reduces lung cancer-related mortality and to evaluate the possible harms of LDCT screening.

SEARCH METHODS

We performed the search in collaboration with the Information Specialist of the Cochrane Lung Cancer Group and included the Cochrane Lung Cancer Group Trial Register, Cochrane Central Register of Controlled Trials (CENTRAL, the Cochrane Library, current issue), MEDLINE (accessed via PubMed) and Embase in our search. We also searched the clinical trial registries to identify unpublished and ongoing trials. We did not impose any restriction on language of publication. The search was performed up to 31 July 2021.  SELECTION CRITERIA: Randomised controlled trials (RCTs) of lung cancer screening using LDCT and reporting mortality or harm outcomes.  DATA COLLECTION AND ANALYSIS: Two review authors were involved in independently assessing trials for eligibility, extraction of trial data and characteristics, and assessing risk of bias of the included trials using the Cochrane RoB 1 tool. We assessed the certainty of evidence using GRADE. Primary outcomes were lung cancer-related mortality and harms of screening. We performed a meta-analysis, where appropriate, for all outcomes using a random-effects model. We only included trials in the analysis of mortality outcomes if they had at least 5 years of follow-up. We reported risk ratios (RRs) and hazard ratios (HRs), with 95% confidence intervals (CIs) and used the I2 statistic to investigate heterogeneity.  MAIN RESULTS: We included 11 trials in this review with a total of 94,445 participants. Trials were conducted in Europe and the USA in people aged 40 years or older, with most trials having an entry requirement of ≥ 20 pack-year smoking history (e.g. 1 pack of cigarettes/day for 20 years or 2 packs/day for 10 years etc.). One trial included male participants only. Eight trials were phase three RCTs, with two feasibility RCTs and one pilot RCT. Seven of the included trials had no screening as a comparison, and four trials had CXR screening as a comparator. Screening frequency included annual, biennial and incrementing intervals. The duration of screening ranged from 1 year to 10 years. Mortality follow-up was from 5 years to approximately 12 years.  None of the included trials were at low risk of bias across all domains. The certainty of evidence was moderate to low across different outcomes, as assessed by GRADE. In the meta-analysis of trials assessing lung cancer-related mortality, we included eight trials (91,122 participants), and there was a reduction in mortality of 21% with LDCT screening compared to control groups of no screening or CXR screening (RR 0.79, 95% CI 0.72 to 0.87; 8 trials, 91,122 participants; moderate-certainty evidence). There were probably no differences in subgroups for analyses by control type, sex, geographical region, and nodule management algorithm. Females appeared to have a larger lung cancer-related mortality benefit compared to males with LDCT screening. There was also a reduction in all-cause mortality (including lung cancer-related) of 5% (RR 0.95, 95% CI 0.91 to 0.99; 8 trials, 91,107 participants; moderate-certainty evidence).  Invasive tests occurred more frequently in the LDCT group (RR 2.60, 95% CI 2.41 to 2.80; 3 trials, 60,003 participants; moderate-certainty evidence). However, analysis of 60-day postoperative mortality was not significant between groups (RR 0.68, 95% CI 0.24 to 1.94; 2 trials, 409 participants; moderate-certainty evidence).  False-positive results and recall rates were higher with LDCT screening compared to screening with CXR, however there was low-certainty evidence in the meta-analyses due to heterogeneity and risk of bias concerns. Estimated overdiagnosis with LDCT screening was 18%, however the 95% CI was 0 to 36% (risk difference (RD) 0.18, 95% CI -0.00 to 0.36; 5 trials, 28,656 participants; low-certainty evidence). Four trials compared different aspects of health-related quality of life (HRQoL) using various measures. Anxiety was pooled from three trials, with participants in LDCT screening reporting lower anxiety scores than in the control group (standardised mean difference (SMD) -0.43, 95% CI -0.59 to -0.27; 3 trials, 8153 participants; low-certainty evidence). There were insufficient data to comment on the impact of LDCT screening on smoking behaviour.  AUTHORS' CONCLUSIONS: The current evidence supports a reduction in lung cancer-related mortality with the use of LDCT for lung cancer screening in high-risk populations (those over the age of 40 with a significant smoking exposure). However, there are limited data on harms and further trials are required to determine participant selection and optimal frequency and duration of screening, with potential for significant overdiagnosis of lung cancer. Trials are ongoing for lung cancer screening in non-smokers.

Targeting lung cancer screening to individuals at greatest risk: the role of genetic factors

Lung cancer (LC) is the most common global cancer. An individual’s risk of developing LC is mediated by an array of factors, including family history of the disease. Considerable research into genetic risk factors for LC has taken place in recent years, with both low-penetrance and high-penetrance variants implicated in increasing or decreasing a person’s risk of the disease. LC is the leading cause of cancer death worldwide; poor survival is driven by late onset of non-specific symptoms, resulting in late-stage diagnoses. Evidence for the efficacy of screening in detecting cancer earlier, thereby reducing lung-cancer specific mortality, is now well established. To ensure the cost-effectiveness of a screening programme and to limit the potential harms to participants, a risk threshold for screening eligibility is required. Risk prediction models (RPMs), which provide an individual’s personal risk of LC over a particular period based on a large number of risk factors, may improve the selection of high-risk individuals for LC screening when compared with generalised eligibility criteria that only consider smoking history and age. No currently used RPM integrates genetic risk factors into its calculation of risk. This review provides an overview of the evidence for LC screening, screening related harms and the use of RPMs in screening cohort selection. It gives a synopsis of the known genetic risk factors for lung cancer and discusses the evidence for including them in RPMs, focusing in particular on the use of polygenic risk scores to increase the accuracy of targeted lung cancer screening.

[Lung Nodules Assessment--Analysis of Four Guidelines]

近20年来，随着计算机断层扫描（computed tomography, CT）技术的提高和肺癌高危人群筛查的普及，越来越多的肺部小结节被发现，然而肺结节的定性诊断仍有很多困难。肺结节是临床上一种常见的现象，恶性结节早期发病比较隐匿，如果不进行早期干预，其病程迅速、恶性程度强、预后差。如果能在早期阶段对病灶进行手术切除，将会明显改善肺癌患者的预后。目前针对肺结节的处理指南层出不穷，但各大指南均未达成统一的共识。本文拟对在国内影响最大的四个指南：美国国家综合癌症网络非小细胞肺癌（non-small cell lung cancer, NSCLC）临床实践指南、美国胸科医师协会肺癌诊疗指南、Fleischner-Society肺结节处理策略指南、肺结节的评估亚洲共识指南所推荐的肺结节诊断和处理策略进行介绍和分析。

Lung cancer screening: history, current perspectives, and future directions

Lung cancer has remained the leading cause of death worldwide among all cancers. The dismal 5-year survival rate of 16% is in part due to the lack of symptoms during early stages and lack of an effective screening test until recently. Chest X-ray and sputum cytology were studied extensively as potential screening tests for lung cancer and were conclusively proven to be of no value. Subsequently, a number of studies compared computed tomography (CT) with the chest X-ray. These studies did identify lung cancer in earlier stages. However, they were not designed to prove a reduction in mortality. Later trials have focused on low-dose CT (LDCT) as a screening tool. The largest US trial - the National Lung Screening Trial (NLST) - enrolled approximately 54,000 patients and revealed a 20% reduction in mortality. While a role for LDCT in lung cancer screening has been established, the issues of high false positive rates, radiation risk, and cost effectiveness still need to be addressed. The guidelines of the international organizations that now include LDCT in lung cancer screening are reviewed. Other methods that may improve earlier detection such as positron emission tomography, autofluorescence bronchoscopy, and molecular biomarkers are also discussed.

Screening for lung cancer with low-dose computed tomography: a review of current status

Screening using low-dose computed tomography (CT) represents an exciting new development in the struggle to improve outcomes for people with lung cancer. Randomised controlled evidence demonstrating a 20% relative lung cancer mortality benefit has led to endorsement of screening by several expert bodies in the US and funding by healthcare providers. Despite this pivotal result, many questions remain regarding technical and logistical aspects of screening, cost-effectiveness and generalizability to other settings. This review discusses the rationale behind screening, the results of on-going trials, potential harms of screening and current knowledge gaps.

Updates and controversies in the rapidly evolving field of lung cancer screening, early detection, and chemoprevention

Lung cancer remains the leading cause of cancer-related death in the United States. Cigarette smoking is a well-recognized risk factor for lung cancer, and a sustained elevation of lung cancer risk persists even after smoking cessation. Despite identifiable risk factors, there has been minimal improvement in mortality for patients with lung cancer primarily stemming from diagnosis at a late stage when there are few effective therapeutic options. Early detection of lung cancer and effective screening of high-risk individuals may help improve lung cancer mortality. While low dose computerized tomography (LDCT) screening of high risk smokers has been shown to reduce lung cancer mortality, the high rates of false positives and potential for over-diagnosis have raised questions on how to best implement lung cancer screening. The rapidly evolving field of lung cancer screening and early-detection biomarkers may ultimately improve the ability to diagnose lung cancer in its early stages, identify smokers at highest-risk for this disease, and target chemoprevention strategies. This review aims to provide an overview of the opportunities and challenges related to lung cancer screening, the field of biomarker development for early lung cancer detection, and the future of lung cancer chemoprevention.

Chemotherapy versus best supportive care for extensive small cell lung cancer

BACKGROUND

Combination chemotherapy has been the mainstay of treatment for extensive stage small celI lung cancer (SCLC) over the last 30 years, even though it only gives a short prolongation in median survival time. The main goal for these patients should be palliation with the aim of improving their quality of life.

OBJECTIVES

To determine the effectiveness of first-line chemotherapy versus placebo or best supportive care (BSC) in prolonging survival in patients with extensive SCLC at diagnosis and the effectiveness of second-line chemotherapy at relapse or progression after first-line chemotherapy compared with BSC or placebo in prolonging survival in patients with extensive SCLC; as well as to evaluate the adverse events of treatment and the quality of life of patients.

SEARCH METHODS

This is the second update of the review. MEDLINE (1966 to October 2013), EMBASE (1974 to October 2013), and the Cochrane Central Register of Controlled Trials (CENTRAL) (2012, Issue 3) were searched. Experts in the field were contacted.

SELECTION CRITERIA

Phase III randomised controlled trials in which any chemotherapy treatment was compared with  placebo or BSC in patients with extensive SCLC, as first-line or second-line therapy at relapse.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed study quality. We resolved disagreements by discussion. Additional information was obtained from one study author.

MAIN RESULTS

Two studies of unclear risk of bias were included for first-line chemotherapy. A total of 88 men under 70 years with good performance status were randomised to receive either supportive care, placebo infusion or ifosfamide. Ifosfamide gave an extra mean survival of 78.5 days compared with supportive care or placebo infusion. Partial tumour response was greater with the active treatment. Toxicity was only seen in the chemotherapy group and quality of life was only assessed at the beginning of treatment. The quality of the evidence for overall survival and adverse effects was very low.Three studies of moderate risk of bias were included for second-line chemotherapy at relapse (one identified in the last search). A total of 932 men and women under 75 years and any performance status were randomised to receive either methotrexate-doxorubicin, topotecan, or picoplatin versus symptomatic treatment or BSC. The methotrexate-doxorubicin treatment gave a median survival of 63 days longer than in the symptomatic-treatment group for patients allocated to receive four cycles of first-line chemotherapy, and 21 days longer for patients allocated to receive eight cycles of first-line chemotherapy.Treatment with topotecan gave a median survival of 84 days longer than in the BSC group (log-rank P = 0.01). The adjusted hazard ratio (HR) for overall survival was 0.61 (95% CI 0.43 to 0.87). Treatment with picoplatin gave a median survival time of six days longer than BSC (HR 0.817, 95% CI 0.65 to 1.03, P = 0.0895). A meta-analysis of topotecan and picoplatin gave a HR of 0.73 (95% CI 0.55 to 0.96, P = 0.03; low-quality evidence).Partial or complete response in the methotrexate-doxorubicin group was 22.3%. Five patients (7%, 95% CI 2.33 to 15.67) showed a partial response with topotecan. No data were provided about tumour response in the picoplatin study. Toxicity was worst in the chemotherapy group (moderate-quality evidence). Quality of life was better in the topotecan group and was not measured in the methotrexate-doxorubicin and picoplatin studies (low-quality evidence).

AUTHORS' CONCLUSIONS

Two small RCTs from the 1970s suggest that first-line chemotherapeutic treatment (based on ifosfamide) may provide a small survival benefit (less than three months) in comparison with supportive care or placebo infusion in patients with advanced SCLC. However platinum-based combination chemotherapy regimens have been shown to increase complete response rates when compared to non-platinum chemotherapy regimens with no significant difference in survival, and so these are currently the standard first-line treatment for patients with SCLC.Second-line chemotherapy at relapse or progression may prolong survival for some weeks in relation to BSC. Nevertheless, the impact of first-line chemotherapy on quality of life, older patients, women and patients with poor prognosis is unknown and the benefits of second-line chemotherapy are also unclear for older people. Globally, the evidence on which these conclusions are based is very scarce and of uncertain or low quality, which calls for well-designed, controlled trials to further evaluate the trade-offs between benefits and risks of different chemotherapeutic schedules in patients with advanced SCLC.

Diagnostic evaluation following a positive lung screening chest radiograph in the Prostate, Lung, Colorectal, Ovarian (PLCO) Cancer Screening Trial

Lung cancer is the major cause of cancer mortality. One of the aims of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) was to determine if annual screening chest radiographs reduce lung cancer mortality. We enrolled 154,900 individuals, aged 55-74 years; 77,445 were randomized to the intervention arm and received an annual chest radiograph for 3 or 4 years. Participants with a positive screen underwent diagnostic evaluation under guidance of their primary physician. Methods of diagnosis or exclusion of cancer, interval from screen to diagnosis, and factors predicting diagnostic testing were evaluated. One or more positive screens occurred in 17% of participants. Positive screens resulted in biopsy in 3%, with 54% positive for cancer. Biopsy likelihood was associated with a mass, smoking, age, and family history of lung cancer. Diagnostic testing stopped after a chest radiograph or computed tomography/magnetic resonance imaging in over half. After a second or subsequent positive screen, evaluation stopped after comparison to prior radiographs in over half. Of 308 screen-detected cancers, the diagnosis was established by thoracotomy/thoracoscopy in 47.7%, needle biopsy in 27.6%, bronchoscopy in 20.1% and mediastinoscopy in 2.9%. Eighty-four percent of screen-detected lung cancers were diagnosed within 6 months. Diagnostic evaluations following a positive screen were conducted in a timely fashion. Lung cancer was diagnosed by tissue biopsy or cytology in all cases. Lung cancer was excluded during evaluation of positive screening examinations by clinical or radiographic evaluation in all but 1.4% who required a tissue biopsy.

Screening for lung cancer: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines

BACKGROUND

Lung cancer is by far the major cause of cancer deaths largely because in the majority of patients it is at an advanced stage at the time it is discovered, when curative treatment is no longer feasible. This article examines the data regarding the ability of screening to decrease the number of lung cancer deaths.

METHODS

A systematic review was conducted of controlled studies that address the effectiveness of methods of screening for lung cancer.

RESULTS

Several large randomized controlled trials (RCTs), including a recent one, have demonstrated that screening for lung cancer using a chest radiograph does not reduce the number of deaths from lung cancer. One large RCT involving low-dose CT (LDCT) screening demonstrated a significant reduction in lung cancer deaths, with few harms to individuals at elevated risk when done in the context of a structured program of selection, screening, evaluation, and management of the relatively high number of benign abnormalities. Whether other RCTs involving LDCT screening are consistent is unclear because data are limited or not yet mature.

CONCLUSIONS

Screening is a complex interplay of selection (a population with sufficient risk and few serious comorbidities), the value of the screening test, the interval between screening tests, the availability of effective treatment, the risk of complications or harms as a result of screening, and the degree with which the screened individuals comply with screening and treatment recommendations. Screening with LDCT of appropriate individuals in the context of a structured process is associated with a significant reduction in the number of lung cancer deaths in the screened population. Given the complex interplay of factors inherent in screening, many questions remain on how to effectively implement screening on a broader scale.

Screening for lung cancer

BACKGROUND

This is an updated version of the original review published in The Cochrane Library in 1999 and updated in 2004 and 2010. Population-based screening for lung cancer has not been adopted in the majority of countries. However it is not clear whether sputum examinations, chest radiography or newer methods such as computed tomography (CT) are effective in reducing mortality from lung cancer.

OBJECTIVES

To determine whether screening for lung cancer, using regular sputum examinations, chest radiography or CT scanning of the chest, reduces lung cancer mortality.

SEARCH METHODS

We searched electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 5), MEDLINE (1966 to 2012), PREMEDLINE and EMBASE (to 2012) and bibliographies. We handsearched the journal Lung Cancer (to 2000) and contacted experts in the field to identify published and unpublished trials.

SELECTION CRITERIA

Controlled trials of screening for lung cancer using sputum examinations, chest radiography or chest CT.

DATA COLLECTION AND ANALYSIS

We performed an intention-to-screen analysis. Where there was significant statistical heterogeneity, we reported risk ratios (RRs) using the random-effects model. For other outcomes we used the fixed-effect model.

MAIN RESULTS

We included nine trials in the review (eight randomised controlled studies and one controlled trial) with a total of 453,965 subjects. In one large study that included both smokers and non-smokers comparing annual chest x-ray screening with usual care there was no reduction in lung cancer mortality (RR 0.99, 95% CI 0.91 to 1.07). In a meta-analysis of studies comparing different frequencies of chest x-ray screening, frequent screening with chest x-rays was associated with an 11% relative increase in mortality from lung cancer compared with less frequent screening (RR 1.11, 95% CI 1.00 to 1.23); however several of the trials included in this meta-analysis had potential methodological weaknesses. We observed a non-statistically significant trend to reduced mortality from lung cancer when screening with chest x-ray and sputum cytology was compared with chest x-ray alone (RR 0.88, 95% CI 0.74 to 1.03). There was one large methodologically rigorous trial in high-risk smokers and ex-smokers (those aged 55 to 74 years with ≥ 30 pack-years of smoking and who quit ≤ 15 years prior to entry if ex-smokers) comparing annual low-dose CT screening with annual chest x-ray screening; in this study the relative risk of death from lung cancer was significantly reduced in the low-dose CT group (RR 0.80, 95% CI 0.70 to 0.92).

AUTHORS' CONCLUSIONS

The current evidence does not support screening for lung cancer with chest radiography or sputum cytology. Annual low-dose CT screening is associated with a reduction in lung cancer mortality in high-risk smokers but further data are required on the cost effectiveness of screening and the relative harms and benefits of screening across a range of different risk groups and settings.

Assessment of lung cancer mortality reduction after chest X-ray screening in smokers: a population-based cohort study in Varese, Italy

BACKGROUND

The effectiveness of screening for lung cancer (LC) in smokers on a population level, as distinct from the special circumstances that may apply in a randomized trial of selected volunteers, has not been thoroughly investigated. Here we evaluate by the standardized mortality ratio (SMR) indicator the impact of a chest X-ray (CXR) screening programme carried out at community level on LC mortality in smokers.

METHODS

All smokers of >10 pack-years, of both genders, ages 45-75 years, resident in 50 communities of the Province of Varese, Italy, screening-eligible, in 1997 were invited by their National Health Service (NHS) general practitioner physicians to a nonrandomized programme of five annual CXR screenings. The entire invitation-to-screen cohort (n=5815 subjects) received NHS usual care, with the addition of CXR exams in volunteer participants (21% of invitees), and was observed through December 2006. To overcome participants' selection bias of LC mortality assessment, for the entire invitation-to-screen cohort we estimated the LC-specific SMR, based on the local reference population receiving the NHS usual care.

RESULTS

Over the 8-year period 1999-2006, a total of 172 cumulative LC deaths were observed in the invitation-to-screen cohort; 210 were expected based on the reference population. Each year in the invited cohort the observed LC deaths were fewer than expected. The cumulative LC SMR was 0.82 (95% CI, 0.67-0.99; p=0.048), suggesting that LC mortality was reduced by 18% with CXR screening.

CONCLUSION

Implementation of a CXR screening programme at community level was associated with a significant reduction of LC mortality in smokers.

Prognostic significance of serum miR-17-5p in lung cancer

miR-17-5p is abnormally expressed in various tumor types. The aim of this study was to investigate the expression level of miR-17-5p in serum of patients with lung cancer and to determine whether serum miR-17-5p expression is related to the prognosis of patients with lung cancer. RT-qPCR was used to examine expression of miRNA-17-5p in 20 pairs of lung cancer and adjacent normal tissues, and sera from 221 patients with lung cancer and 54 matched controls. The correlation of serum miR-17-5p with clinicopathological factors or prognosis of patients with lung cancer was analyzed. The expression level of miR-17-5p obviously increased in lung cancer tissues (P = 0.004). Furthermore, serum miR-17-5p expression also significantly increased in patients with lung cancer compared with healthy individuals (P = 0.03). The survival analysis showed that serum miR-17-5p expression was closely related to the survival of patients with lung cancer. Patients with high miR-17-5p expression had shorter survival times [hazard ratio (HR) = 1.767, 95 %CI 1.039-3.005, P = 0.035]. A lower expression level of serum miR-17-5p helps extend the survival of patients with lung cancer. Thus, miR-17-5p may be potential biomarker for prediction the prognosis in patients with lung cancer.

Overwhelming support among urban Irish COPD patients for lung cancer screening by low-dose CT scan

PURPOSE

The National Lung Screening Trial (NLST) has renewed interest in low-dose computed tomography (LDCT) screening for lung cancer. Smokers may be less receptive toward LDCT screening, however, compared with never smokers. The views of patients with COPD, a particularly high-risk group, toward LDCT screening for lung cancer are currently unknown. We therefore evaluated attitudes of patients with COPD toward LDCT screening for lung cancer.

METHODS

Interviews with Irish patients with COPD who satisfied NLST eligibility criteria were conducted in clinical settings using a questionnaire based on that of a comparable study of U.S. current/former smokers of unspecified disease status.

RESULTS

A total of 142 subjects had a mean age of 65.09 ± 6.07 years (46.4 % were male, mean pack years 54.5 ± 33.3, mean FEV1 59.16 ± 23 %); 97.8 % had an identifiable usual source of healthcare. Compared with data from a U.S. cohort of current/former smokers, a higher proportion of Irish COPD smokers: believed that they were at risk for lung cancer (63.6 vs. 15.7 %); believed that early detection improved chances of survival (90 vs. 51.2 ); were willing to consider LDCT screening (97.9 vs. 78.6 %); were willing to pay for a LDCT scan (68.6 vs. 36.2 %); and were willing to accept treatment recommendations arising (95.7 vs. 56.2 %; p < 0.0001 for all comparisons).

CONCLUSIONS

Urban Irish smokers with COPD who would be eligible for LDCT screening are almost universally in favor of being screened and treated for screening-detected lung cancers. This readily accessible high-risk population should be actively targeted in future screening programs.

Awareness of risk factors among persons at risk for lung cancer, chronic obstructive pulmonary disease and sleep apnea: a Canadian population-based study

OBJECTIVE

To assess awareness among persons at risk for lung cancer, chronic obstructive pulmonary disease (COPD) and sleep apnea regarding symptoms and risk factors of the disease, and their attitudes regarding the disease and toward those who are affected.

METHODS

A quantitative hybrid telephone and Internet survey of a representative population of Canadian adults at risk for at least one of the three diseases was conducted. To measure the awareness and attitudes of First Nations, Inuit and Métis people to these diseases, a proportionate number were also surveyed.&nbsp;

RESULTS

A total of 3626 individuals were contacted. Of these, 3036 (84%) were eligible to participate. Of those at risk for lung cancer and COPD, 65% and 69%, respectively, were due to tobacco smoke exposure. Among those at risk, 72% believed that they were informed about lung cancer compared with 36% for COPD and 56% for sleep apnea. Most respondents were knowledgeable about the common symptoms of lung cancer, COPD and sleep apnea, but were less aware of the impact lifestyle choices could have on the development of these disorders and the availability of treatment. Most of the participants (77%) believed that smoking was an addiction rather than a habit (19%). There were no significant differences in the awareness of risk factors, symptoms and attitudes toward all three lung diseases between First Nations, Inuit and Métis people and the general population.

CONCLUSIONS

Canadians are reasonably aware of risk factors and symptoms for lung cancer and sleep apnea. However, there is poor awareness of COPD as a disease entity. There is a lack of appreciation for the impact lifestyle choices and changes can have on lung diseases.

MicroRNAs: novel biomarkers for lung cancer diagnosis, prediction and treatment

MicroRNAs (miRNAs) are short non-protein-coding RNAs that post-transcriptionally regulate mRNA expression. A large body of evidence has identified important roles for these regulators in cell proliferation, differentiation, apoptosis and metabolism, as well as activation of oncogenic and antioncogenic signals. Aberrant expression of miRNAs has been found in most human malignancies and is strongly associated with tumorigenesis, prediction, diagnosis, progress, treatment and prognosis. Thus, miRNAs may become an intriguing and promising therapeutic target for many diseases, including cancer. In addition, research into miRNAs may provide insight into the mechanisms underlying tumor occurrence, progression and metastasis. This review summarizes the current knowledge of miRNAs, their roles in lung cancer and avenues for future research.

Increased levels of circulating interleukin 6, interleukin 8, C-reactive protein, and risk of lung cancer

BACKGROUND

Previous studies that were based primarily on small numbers of patients suggested that certain circulating proinflammatory cytokines may be associated with lung cancer; however, large independent studies are lacking.

METHODS

Associations between serum interleukin 6 (IL-6) and interleukin 8 (IL-8) levels and lung cancer were analyzed among 270 case patients and 296 control subjects participating in the National Cancer Institute-Maryland (NCI-MD) case-control study. Results were validated in 532 case patients and 595 control subjects in a nested case-control study within the prospective Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. Association with C-reactive protein (CRP), a systemic inflammation biomarker, was also analyzed. Associations between biomarkers and lung cancer were estimated using logistic regression models adjusted for smoking, stage, histology, age, and sex. The 10-year standardized absolute risks of lung cancer were estimated using a weighted Cox regression model.

RESULTS

Serum IL-6 and IL-8 levels in the highest quartile were associated with lung cancer in the NCI-MD study (IL-6, odds ratio [OR] = 3.29, 95% confidence interval [CI] = 1.88 to 5.77; IL-8, OR = 2.06, 95% CI = 1.19 to 3.57) and with lung cancer risk in the PLCO study (IL-6, OR = 1.48, 95% CI = 1.04 to 2.10; IL-8, OR = 1.57, 95% CI = 1.10 to 2.24), compared with the lowest quartile. In the PLCO study, increased IL-6 levels were only associated with lung cancer diagnosed within 2 years of blood collection, whereas increased IL-8 levels were associated with lung cancer diagnosed more than 2 years after blood collection (OR = 1.57, 95% CI = 1.15 to 2.13). The 10-year standardized absolute risks of lung cancer in the PLCO study were highest among current smokers with high IL-8 and CRP levels (absolute risk = 8.01%, 95% CI = 5.77% to 11.05%).

CONCLUSIONS

Although increased levels of both serum IL-6 and IL-8 are associated with lung cancer, only IL-8 levels are associated with lung cancer risk several years before diagnosis. Combination of IL-8 and CRP are more robust biomarkers than either marker alone in predicting subsequent lung cancer.

Volunteer effect and compromised randomization in the Mayo Project of screening for lung cancer

It has been confirmed recently that the volunteer effect in lung cancer screening is characterized by higher lung cancer mortality risk in self-selected screening participants. The Mayo Lung Project, the most influential trial of screening for lung cancer ever completed, was conducted in nonvolunteer Mayo Clinic outpatients, with a peculiar study design that rendered the randomization vulnerable to the volunteer effect. Of all nonvolunteers randomized in the Mayo Lung Project, only those allocated in the screened group were asked consent to participate in the trial. The final Mayo Lung Project report stated that 655 randomized nonvolunteers refused screening and were excluded from the study, thus documenting violation of the rule that no selection should occur after randomization. The long-term follow-up of the Mayo Lung Project showed an enigmatic result which has never been explained: the lung cancer mortality was 13% higher in the screening intervention group than in the control group [4.4 (95% CI 3.9-4.9) vs. 3.9 (95% CI 3.5-4.4) per 1,000 person-years; P = 0.09]. Such overrepresented mortality is consistent with the volunteer effect and supports the concept that the Mayo Lung Project randomization was compromised by the post-randomization self-selection of participant nonvolunteers.

The implementation of screening for prostate cancer

The objective of this study was to determine whether screening for prostate cancer (PC) reduces PC mortality and, if so, whether the required criteria to be introduced as a population-based screening program are satisfied. A literature review was conducted through electronic scientific databases. The screening tests, that is, PSA and digital rectal examination, have limited sensitivity and specificity for detecting PC; screening produces a beneficial stage shift and reduces PC mortality. Nevertheless, PC screening causes a large increase in the cumulative incidence, and the understanding of the economic cost and quality-of-life parameters are limited. PC screening cannot be justified yet in the context of a public health policy.

Lung cancer screening in the randomized Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial

BACKGROUND

The 5-year overall survival rate of lung cancer patients is approximately 15%. Most patients are diagnosed with advanced-stage disease and have shorter survival rates than patients with early-stage disease. Although screening for lung cancer has the potential to increase early diagnosis, it has not been shown to reduce lung cancer mortality rates. In 1993, the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial was initiated specifically to determine whether screening would reduce mortality rates from PLCO cancers.

METHODS

A total of 77 464 participants, aged 55-74 years, were randomly assigned to the intervention arm of the PLCO Cancer Screening Trial between November 8, 1993, and July 2, 2001. Participants received a baseline chest radiograph (CXR), followed by three annual single-view CXRs at the 10 US screening centers. Cancers were classified as screen detected and nonscreen detected (interval or never screened) and according to tumor histology. The positivity rates of screen-detected cancers and positive predictive values (PPVs) were calculated. Because 51.6% of the participants were current or former smokers, logistic regression analysis was performed to control for smoking status. All statistical tests were two-sided.

RESULTS

Compliance with screening decreased from 86.6% at baseline to 78.9% at the last screening. Overall positivity rates were 8.9% at baseline and 6.6%-7.1% at subsequent screenings; positivity rates increased modestly with smoking risk categories (P(trend) < .001). The PPVs for all participants were 2.0% at baseline and 1.1%, 1.5%, and 2.4% at years 1, 2, and 3, respectively; PPVs in current smokers were 5.9% at baseline and 3.3%, 4.2%, and 5.6% at years 1, 2, and 3, respectively. A total of 564 lung cancers were diagnosed, of which 306 (54%) were screen-detected cancers and 87% were non-small cell lung cancers. Among non-small cell lung cancers, 59.6% of screen-detected cancers and 33.3% of interval cancers were early (I-II) stage.

CONCLUSIONS

The PLCO Cancer Screening Trial demonstrated the ability to recruit, retain, and screen a large population over multiple years at multiple centers. A higher proportion of screen-detected lung cancers were early stage, but a conclusion on the effectiveness of CXR screening must await final PLCO results, which are anticipated at the end of 2015.

Estimating the risks and benefits of nicotine replacement therapy for smoking cessation in the United States

OBJECTIVES

To compare potential population-wide benefits and risks, we examined the potential impact of increased nicotine replacement therapy (NRT) use for smoking cessation on future US mortality.

METHODS

We developed a simulation model incorporating a Monte Carlo uncertainty analysis, with data from the 2005 National Health Interview Survey and Cancer Prevention Study II. We estimated the number of avoided premature deaths from smoking attributable to increased NRT use, before and after incorporating assumptions about NRT harm.

RESULTS

We estimate that a gradual increase in the proportion of NRT-aided quit attempts to 100% by 2025 would lead to 40,000 (95% credible interval=31,000, 50,000) premature deaths avoided over a 20-year period. Most avoided deaths would be attributable to lung cancer and cardiovascular disease. After we incorporated assumptions about potential risk from long-term NRT, the estimate of avoided premature deaths from all causes declined to 32 000.

CONCLUSIONS

Even after we assumed some harm from long-term NRT use, the benefits from increased cessation success far outweigh the risks. However, the projected reduction in premature mortality still reflects a small portion of the tobacco-related deaths expected over a 20-year period.

Lung cancer: current diagnosis and treatment

BACKGROUND

Much progress has been made in the treatment of lung cancer in the last ten years (adjuvant chemotherapy, targeted therapy, individualized therapy). Nonetheless, lung cancer is still the leading cause of death due to cancer and thus remains a major medical, scientific, and social problem.

METHOD

This review is based on national and international recommendations and selected articles from the literature.

RESULTS

Cigarette smoking is the major pathogenic factor for lung cancer. Lung cancer can be divided into two major types that differ in their biological behavior, small cell lung cancer and non-small cell lung cancer. Whenever possible, the diagnosis should be confirmed by biopsy, the extent of disease should be documented in detail (international TNM classification/staging), and the patient's functional level should be assessed with a view toward treatment planning. Surgery for non-small cell lung cancer with curative intent is possible up to stage IIIA, while stage IIIB is the domain of radiotherapy. Surgery for small cell lung cancer with curative intent is possible for rare cases in early stages (T1N0 and T2N0, i.e., stage IA and IB). As long as small cell lung cancer is restricted to one side of the chest, simultaneous radiation therapy and chemotherapy are indicated. If a malignant pleural effusion or distant metastases are present, both lung cancers are treated palliatively with platinum-based chemotherapy.

Chemotherapy versus best supportive care for extensive small cell lung cancer

BACKGROUND

Combination chemotherapy has been the mainstay of treatment for extensive stage small celI lung cancer (SCLC) over the last 30 years even though it only gives a short prolongation in median survival time. The main goal for these patients should be palliation with the aim of improving their quality of life.

OBJECTIVES

To evaluate the effectiveness of chemotherapy in extensive SCLC compared with best supportive care (BSC) or placebo treatment.

SEARCH STRATEGY

MEDLINE (1966 to July 2008), EMBASE (1974 to week 31, 2008), and the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 3, 2008). Experts in the field were contacted.

SELECTION CRITERIA

Randomised controlled trials in which any chemotherapy treatment was compared with placebo or BSC in patients with extensive SCLC, as first or second therapy at relapse.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed study quality. We resolved disagreements by discussion. Additional information was obtained from one study author.

MAIN RESULTS

Two studies were included for first-line chemotherapy. A total of 65 patients were randomised to receive either placebo or ifosfamide. Ifosfamide gave an extra mean survival of 78.5 days compared with placebo. Partial tumour response was greater with the active treatment. Toxicity was only seen in the chemotherapy group.Two studies were included for second-line chemotherapy at relapse. A total of 531 patients were randomised to receive either methotrexate-doxorubicin or symptomatic treatment, or to receive oral topotecan versus BSC. The methotrexate-doxorubicin treatment gave a median survival of 63 days longer than in the symptomatic treatment group, and 21 days longer for patients allocated to receive four or eight cycles of first-line chemotherapy, respectively.Treatment with topotecan gave a median survival of 84 days longer than in the BSC group (log-rank P = 0.01). The adjusted hazard ratio for overall survival was 0.61 (95% CI, 0.43 to 0.87). Partial or complete response in the methotrexate-doxorubicin group was 22.3%. Five patients (7%, 95% CI, 2.33 to 15.67) showed a partial response with topotecan. Toxicity was worst in the chemotherapy group. Quality of life was better in the topotecan group.

AUTHORS' CONCLUSIONS

Chemotherapeutic treatment prolongs survival in comparison with placebo in patients with advanced SCLC. Nevertheless, the impact of first-line chemotherapy on quality of life and in patients with poor prognosis is unknown. Well-designed, controlled trials are needed to further evaluate the risks and benefits of different chemotherapeutic schedules in patients with advanced SCLC.

CT lung cancer screening in the UK

Lung cancer is the most common cause of cancer-related death in the UK. Despite aggressive primary prevention measures and improved medical care, the 5-year survival rate is less than 10% for patients in the UK who present with symptoms. The possibility of CT screening for lung cancer provides some hope of reducing mortality. However, the case for screening remains unproven. This article explores the issues surrounding lung cancer screening in the context of historical studies, trials in progress and tentative plans for a UK CT lung cancer screening trial.

Chest X-rays in COPD screening: are they worthwhile?

The BTS/NICE COPD guideline recommends a chest X-ray at initial COPD evaluation; this is a grade D recommendation based on expert opinion. We have investigated which pathologies other than COPD are detected by chest X-ray and how they alter management. Dundee smokers aged 40 or over and receiving bronchodilators are assessed for COPD by their practice nurse and offered a chest X-ray if there is no record of a chest X-ray within the previous three years. We retrospectively analysed the chest X-ray reports and case records of these patients. The chest X-ray report was structured with 7 specific questions, most importantly "Are there any features of other disease likely to be causing dyspnoea?" and "Are there any features to suggest lung cancer?" Management of patients with chest X-ray findings suggesting other disease causing dyspnoea or lung cancer was assessed by questionnaire and case record study. Five hundred forty-six consecutive chest X-ray reports were analysed. Fourteen percent of all chest X-rays detected potentially treatable dyspnoea causing disease; where management following receipt of X-ray reports was audited, 84% were thought to help. Eleven lung cancers were detected, 3 had stage 1 disease. Considerable benign and malignant pathology is detected by chest X-ray performed at initial COPD assessment. Clinical management is changed in the majority with a potentially treatable abnormality. This evidence suggests that the NICE guideline to perform chest X-ray at initial COPD evaluation should be elevated from a grade D to grade C recommendation.

Exosomal microRNA: a diagnostic marker for lung cancer

PURPOSE

To date, there is no screening test for lung cancer shown to affect overall mortality. MicroRNAs (miRNAs) are a class of small noncoding RNA genes found to be abnormally expressed in several types of cancer, suggesting a role in the pathogenesis of human cancer.

PATIENTS AND METHODS

We evaluated the circulating levels of tumor exosomes, exosomal small RNA, and specific exosomal miRNAs in patients with and without lung adenocarcinoma, correlating the levels with the American Joint Committee on Cancer (AJCC) disease stage to validate it as an acceptable marker for diagnosis and prognosis in patients with adenocarcinoma of the lung.

RESULTS

To date, 27 patients with lung adenocarcinoma AJCC stages I-IV and 9 controls, all aged 21-80 years, were enrolled in the study. Small RNA was detected in the circulating exosomes. The mean exosome concentration was 2.85 mg/mL (95% CI, 1.94-3.76) for the lung adenocarcinoma group versus 0.77 mg/mL (95% CI, 0.68-0.86) for the control group (P < .001). The mean miRNA concentration was 158.6 ng/mL (95% CI, 145.7-171.5) for the lung adenocarcinoma group versus 68.1 ng/mL (95% CI, 57.2-78.9) for the control group (P < .001). Comparisons between peripheral circulation miRNA-derived exosomes and miRNA-derived tumors indicated that the miRNA signatures were not significantly different.

CONCLUSION

The significant difference in total exosome and miRNA levels between lung cancer patients and controls, and the similarity between the circulating exosomal miRNA and the tumor-derived miRNA patterns, suggest that circulating exosomal miRNA might be useful as a screening test for lung adenocarcinoma. No correlation between the exosomal miRNA levels and the stage of disease can be made at this point.

Cancer screening in men

Cancer screening is one of the most common requests directed to primary care physicians in the office setting. In this article, we look at current recommendations, evidence for, and controversy surrounding screening for cancers of the lung, colon, and prostate, which together account for 51% of cancer deaths in men. We also look at screening for testicular cancer, which, although a relatively minor contributor to cancer mortality, is a prototypically male cancer with a proposed screening test.

Screening and chemoprevention in lung cancer

Lung cancer is a major health problem due to its incidence and mortality. The risk factors, the existence of a preclinical phase, and the relationship between stage at diagnosis and survival are known. A number of strategies that aim to diagnose lung cancer in its earliest stages, based principally on imaging studies, are therefore being tested. Several drugs aimed at reducing the probability of developing lung cancer in the at-risk population are also under study. At the present time, the results obtained have not been encouraging and we do not have a clear strategy either for early diagnosis or for the use of chemopreventive agents.

Cancer screening in renal transplant recipients: what is the evidence?

Increased cancer risk is well established in the renal transplant population. Little, however, is known about the benefits and harms of cancer screening, treatment effectiveness, and the overall cancer prognosis in renal transplant recipients. In this study, we critically appraised guidelines for cancer screening in the renal transplant and general populations using standard criteria for an evidence-based screening program. Guidelines were included when they were applied to adult participants, had objectives specific to cancer screening, and were written in English. Recommendations for breast and colorectal cancer screening in the general population were supported by evidence of cancer-specific mortality benefits from randomized, controlled trials of cancer screening. Convincing evidence from observational studies had demonstrated population cervical cancer screening was effective, also, test performance of mammography, faecal occult blood testing, and Pap smear were accurate. Population breast, colorectal, and cervical cancer screening also appeared to be good value for money in the general population. On the contrary, recommendations for cancer screening in renal transplant recipients were entirely extrapolated from data in the general population. Studies in the general population have led to the development of cancer screening guidelines in transplant recipients. Because of increased cancer risk, differences in diagnostic test performance, competing risks for deaths from causes such as cardiovascular disease and reduced overall life expectancies, validity of their recommendations are uncertain. Future studies are needed to address these issues to provide the necessary evidence for informed decision-making.

Computed tomography screening for lung cancer

Results of randomised trials are needed before recommending its adoption

Screening chest radiography: results from a Greek cross-sectional survey

Background

Public health authorities worldwide discourage the use of chest radiography as a screening modality, as the diagnostic performance of chest radiography does not justify its application for screening and may even be harmful, since people with false positive results may experience anxiety and concern. Despite the accumulated evidence, various reports suggest that primary care physicians throughout the world still prescribe chest radiography for screening. We therefore set out to index the use of chest radiography for screening purposes among the healthy adult population and to analyze its relationship with possible trigger factors.

Methods

The study was designed as a cross-sectional survey. Five thousand four hundred and ninety-nine healthy adults, coming from 26 Greek provinces were surveyed for screening practice habits in the nationwide anticancer study. Data were obtained for the use of screening chest radiography. Impact of age, gender, tobacco exposure, family history positive for malignancies and professional-risk for lung diseases was further analyzed.

Results

we found that 20% (n = 1099) of the surveyed individuals underwent chest radiography for screening purposes for at least one time during the previous three years. Among those, 24% do so with a frequency equal or higher than once yearly, and 48% with a frequency equal or higher than every three years. Screening for chest radiography was more commonly adopted among males (OR 1.130, 95% CI 0.988–1.292), pensioners (OR 1.319, CI 1.093–1.593) and individuals with a positive family history for lung cancer (OR 1.251, CI 0.988–1.583). Multivariate analysis confirmed these results.

Conclusion

Despite formal recommendations, chest radiography for screening purposes was a common practice among the analyzed sample of Greek adults. This practice is of questionable value since the positive predictive value of chest radiography is low. The implementation of even a relatively inexpensive imaging study on a national scale would greatly burden health economics and the workload of radiology departments.

Cochrane systematic reviews of treatments for lung cancer

Morbidity and mortality from lung cancer is a major burden to global health. The integration of expert clinical experience, patient preference and high-quality evidence, including Cochrane systematic reviews, can only help improve outcomes from this highly lethal condition.

Causes of cancer in the world: comparative risk assessment of nine behavioural and environmental risk factors

INTRODUCTION

With respect to reducing mortality, advances in cancer treatment have not been as effective as those for other chronic diseases; effective screening methods are available for only a few cancers. Primary prevention through lifestyle and environmental interventions remains the main way to reduce the burden of cancers. In this report, we estimate mortality from 12 types of cancer attributable to nine risk factors in seven World Bank regions for 2001.

METHODS

We analysed data from the Comparative Risk Assessment project and from new sources to assess exposure to risk factors and relative risk by age, sex, and region. We applied population attributable fractions for individual and multiple risk factors to site-specific cancer mortality from WHO.

FINDINGS

Of the 7 million deaths from cancer worldwide in 2001, an estimated 2.43 million (35%) were attributable to nine potentially modifiable risk factors. Of these, 0.76 million deaths were in high-income countries and 1.67 million in low-and-middle-income nations. Among low-and-middle-income regions, Europe and Central Asia had the highest proportion (39%) of deaths from cancer attributable to the risk factors studied. 1.6 million of the deaths attributable to these risk factors were in men and 0.83 million in women. Smoking, alcohol use, and low fruit and vegetable intake were the leading risk factors for death from cancer worldwide and in low-and-middle-income countries. In high-income countries, smoking, alcohol use, and overweight and obesity were the most important causes of cancer. Sexual transmission of human papilloma virus is a leading risk factor for cervical cancer in women in low-and-middle-income countries.

INTERPRETATION

Reduction of exposure to key behavioural and environmental risk factors would prevent a substantial proportion of deaths from cancer.

Overview of observational studies of low-dose helical computed tomography screening for lung cancer

OBJECTIVE

Lung cancer is a substantial public health problem in Western countries. Evidence from previous controlled trials of chest radiography and sputum cytology does not support lung cancer screening, but computed tomography (CT) screening has recently emerged as a more sensitive screening tool. For the present article, the available observational studies of low-dose helical CT screening for lung cancer were reviewed.

METHODOLOGY

An evidence-based review of all published observational studies of low-dose helical CT screening for lung cancer, identified by an extensive search of Medline, was conducted.

RESULTS

Eight observational studies of CT screening for lung cancer were identified. Relative to chest radiography, low-dose helical CT is a sensitive screening tool and can detect a high proportion of small lung cancers at an early and resectable stage. The yield of sputum cytology in addition to CT screening appears to be relatively low. To date, 5-year lung cancer survival of all individuals participating in baseline screening has not been reported for any of the studies.

CONCLUSIONS

Although these preliminary studies are very promising, it remains to be proven that the early detection and treatment of lung cancer will lead to a reduction in mortality. This issue will be addressed by randomized controlled trials. In the interim, the long-term follow up of these observational studies could provide further insights.