Extended lung cancer incidence follow-up in the Mayo Lung Project and overdiagnosis

Cancer Screening, Incidental Detection, and Overdiagnosis

BACKGROUND

In the past, patients were only diagnosed with cancer because they had symptoms. Now, because of screening and incidental detection, some patients are diagnosed with cancer when they are asymptomatic. While this shift is typically viewed as desirable, it has produced an unfortunate side-effect: it is now possible to be diagnosed with a cancer not destined to cause symptoms or death-a phenomenon labeled as overdiagnosis.

CONTENT

We begin with a brief introduction to the heterogeneity of cancer progression: at one extreme, some cancers are already systemic by the time they are detectable; at the other, some grow extremely slowly or even regress. The ensuing sections describe the evidence that the pursuit of earlier detection has led to overdiagnosis. Although rarely confirmed in an individual, overdiagnosis is readily identifiable in a long-term follow-up of a randomized trial of screening. Furthermore, 2 population signatures for overdiagnosis exist: (a) rising incidence coupled with stable mortality and (b) rising early-stage incidence coupled with stable late-stage incidence. Finally, we review the misleading feedback produced by overdiagnosis-such as rising 5-year survival rates and more cancer survivors. This feedback is erroneously interpreted as reinforcing the value of early detection, encourages more screening/incidental detection and, ironically, promotes more overdiagnosis.

SUMMARY

Overdiagnosis is an unintended consequence of the desire to detect cancer early. Given the evolving understanding that tumor biology and host response are more relevant to prognosis than early vs late diagnosis, it is time to challenge the assertion that early diagnosis is always the best approach to curing cancer.

Lung Cancer Screening with Low-Dose CT: What We Have Learned in Two Decades of ITALUNG and What Is Yet to Be Addressed

The ITALUNG trial started in 2004 and compared lung cancer (LC) and other-causes mortality in 55-69 years-aged smokers and ex-smokers who were randomized to four annual chest low-dose CT (LDCT) or usual care. ITALUNG showed a lower LC and cardiovascular mortality in the screened subjects after 13 years of follow-up, especially in women, and produced many ancillary studies. They included recruitment results of a population-based mimicking approach, development of software for computer-aided diagnosis (CAD) and lung nodules volumetry, LDCT assessment of pulmonary emphysema and coronary artery calcifications (CAC) and their relevance to long-term mortality, results of a smoking-cessation intervention, assessment of the radiations dose associated with screening LDCT, and the results of biomarkers assays. Moreover, ITALUNG data indicated that screen-detected LCs are mostly already present at baseline LDCT, can present as lung cancer associated with cystic airspaces, and can be multiple. However, several issues of LC screening are still unaddressed. They include the annual vs. biennial pace of LDCT, choice between opportunistic or population-based recruitment. and between uni or multi-centre screening, implementation of CAD-assisted reading, containment of false positive and negative LDCT results, incorporation of emphysema. and CAC quantification in models of personalized LC and mortality risk, validation of ultra-LDCT acquisitions, optimization of the smoking-cessation intervention. and prospective validation of the biomarkers.

Cancer overdiagnosis: a challenge in the era of screening

"Screening" is a search for preclinical, asymptomatic disease, including cancer. Widespread cancer screening has led to large increases in early-stage cancers and pre-cancers. Ubiquitous public messages emphasize the potential benefits to screening for these lesions based on the underlying assumption that treating cancer at early stages before spread to other organs should make it easier to treat and cure, using more tolerable interventions. The intuition is so strong that public campaigns are sometimes launched without conducting definitive trials directly comparing screening to usual care. An effective cancer screening test should not only increase the incidence of early-stage preclinical disease but should also decrease the incidence of advanced and metastatic cancer, as well as a subsequent decrease in cancer-related mortality. Otherwise, screening efforts may be uncovering a reservoir of non-progressive and very slowly progressive lesions that were not destined to cause symptoms or suffering during the person's remaining natural lifespan: a phenomenon known as "overdiagnosis." We provide here a qualitative review of cancer overdiagnosis and discuss specific examples due to extensive population-based screening, including neuroblastoma, prostate cancer, thyroid cancer, lung cancer, melanoma, and breast cancer. The harms of unnecessary diagnosis and cancer therapy call for a balanced presentation to people considering undergoing screening, even with a test of accepted benefit, with a goal of informed decision-making. We also discuss proposed strategies to mitigate the adverse sequelae of overdiagnosis.

The influence of postscreening follow-up time and participant characteristics on estimates of overdiagnosis from lung cancer screening trials

We aimed to explore the underlying reasons that estimates of overdiagnosis vary across and within low-dose computed tomography (LDCT) lung cancer screening trials. We conducted a systematic review to identify estimates of overdiagnosis from randomised controlled trials of LDCT screening. We then analysed the association of Ps (the excess incidence of lung cancer as a proportion of screen-detected cases) with postscreening follow-up time using a linear random effects meta-regression model. Separately, we analysed annual Ps estimates from the US National Lung Screening Trial (NLST) and German Lung Cancer Screening Intervention Trial (LUSI) using exponential decay models with asymptotes. We conducted stratified analyses to investigate participant characteristics associated with Ps using the extended follow-up data from NLST. Among 12 overdiagnosis estimates from 8 trials, the postscreening follow-up ranged from 3.8 to 9.3 years, and Ps ranged from -27.0% (ITALUNG, 8.3 years follow-up) to 67.2% (DLCST, 5.0 years follow-up). Across trials, 39.1% of the variation in Ps was explained by postscreening follow-up time. The annual changes in Ps were -3.5% and -3.9% in the NLST and LUSI trials, respectively. Ps was predicted to plateau at 2.2% for NLST and 9.2% for LUSI with hypothetical infinite follow-up. In NLST, Ps increased with age from -14.9% (55-59 years) to 21.7% (70-74 years), and time trends in Ps varied by histological type. The findings suggest that differences in postscreening follow-up time partially explain variation in overdiagnosis estimates across lung cancer screening trials. Estimates of overdiagnosis should be interpreted in the context of postscreening follow-up and population characteristics.

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.

Cancer Screening and Surveillance Testing for Older Adult Cancer Survivors

In older adult cancer survivors, cancer screening and surveillance testing carry benefits and harms that depend on a variety of factors. Benefits of screening include early diagnosis and a lower risk of death from cancer. Harms include false-positive results, unnecessary biopsies, incidental findings, and overdiagnosis. The primary factor in deciding whether older adult cancer survivors should undergo screening or surveillance testing is life expectancy, but other factors also come into play, such as a patient’s health status, goals, and values. An individualized approach as well as shared decision-making are crucial when working with patients to make these important decisions.

A new perspective on breast cancer diagnostic guidelines to reduce overdiagnosis

Overdiagnosis of breast cancer, defined as diagnosing a cancer that would otherwise not cause symptoms or death in a patient's lifetime, costs U.S. health care system over $1.2 billion annually. Overdiagnosis rates, estimated to be around 10%-40%, may be reduced if indolent breast findings can be identified and followed with noninvasive imaging rather than biopsy. However, there are no validated guidelines for radiologists to decide when to choose imaging options recognizing cancer grades and types. The aim of this study is to optimize breast cancer diagnostic decisions based on cancer types using a large-scale finite-horizon Markov decision process (MDP) model with 4.6 million states to help reduce overdiagnosis. We prove the optimality of a divide-and-search algorithm that relies on tight upper bounds on the optimal decision thresholds to find an exact optimal solution. We project the high-dimensional MDP onto two lower dimensional MDPs and obtain feasible upper bounds on the optimal decision thresholds. We use real data from two private mammography databases and demonstrate our model performance through a previously validated simulation model that has been used by the policy makers to set the national screening guidelines in the United States. We find that a decision-analytical framework optimizing diagnostic decisions while accounting for breast cancer types has a strong potential to improve the quality of life and alleviate the immense costs of overdiagnosis. Our model leads to a 20 % reduction in overdiagnosis on the screening population, which translates into an annual savings of approximately $300 million for the U.S. health care system.

Nationwide lung cancer screening with low-dose computed tomography: implementation and first results of the HUNCHEST screening program

OBJECTIVES

Lung cancer (LC) kills more people than any other cancer in Hungary. Hence, there is a clear rationale for considering a national screening program. The HUNCHEST pilot program primarily aimed to investigate the feasibility of a population-based LC screening in Hungary, and determine the incidence and LC probability of solitary pulmonary nodules.

METHODS

A total of 1890 participants were assigned to undergo low-dose CT (LDCT) screening, with intervals of 1 year between procedures. Depending on the volume, growth, and volume doubling time (VDT), screenings were defined as negative, indeterminate, or positive. Non-calcified lung nodules with a volume > 500 mm³ and/or a VDT < 400 days were considered positive. LC diagnosis was based on histology.

RESULTS

At baseline, the percentage of negative, indeterminate, and positive tests was 81.2%, 15.1%, and 3.7%, respectively. The frequency of positive and indeterminate LDCT results was significantly higher in current smokers (vs. non-smokers or former smokers; p < 0.0001) and in individuals with COPD (vs. those without COPD, p < 0.001). In the first screening round, 1.2% (n = 23) of the participants had a malignant lesion, whereas altogether 1.5% (n = 29) of the individuals were diagnosed with LC. The overall positive predictive value of the positive tests was 31.6%. Most lung malignancies were diagnosed at an early stage (86.2% of all cases).

CONCLUSIONS

In terms of key characteristics, our prospective cohort study appears consistent to that of comparable studies. Altogether, the results of the HUNCHEST pilot program suggest that LDCT screening may facilitate early diagnosis and thus curative-intent treatment in LC.

KEY POINTS

• The HUNCHEST pilot study is the first nationwide low-dose CT screening program in Hungary. • In the first screening round, 1.2% of the participants had a malignant lesion, whereas altogether 1.5% of the individuals were diagnosed with lung cancer. • The overall positive predictive value of the positive tests in the HUNCHEST screening program was 31.6%.

Racially Conscious Cancer Screening Guidelines: A Path Towards Culturally Competent Science

OBJECTIVE

To review the racial composition of the study populations that the current USPSTF screening guidelines for lung, breast, and colorectal cancer are based on, and the effects of their application across non-white individuals.

SUMMARY OF BACKGROUND DATA

USPSTF guidelines commonly become the basis for establishing standards of care, yet providers are often unaware of the racial composition of the study populations they are based on.

METHODS

We accessed the USPSTF screening guidelines for lung, breast, and colorectal cancer via their website, and reviewed all referenced publications for randomized controlled trials (RCTs), focusing on the racial composition of their study populations. We then used PubMed to identify publications addressing the generalizability of such guidelines across non-white individuals. Lastly, we reviewed all guidelines published by non-USPSTF organizations to identify the availability of race-specific recommendations.

RESULTS

Most RCTs used as basis for the current USPSTF guidelines either did not report race, or enrolled cohorts that were not representative of the U.S. population. Several studies were identified demonstrating the broad application of such guidelines across non-white individuals can lead to underdiagnosis and higher levels of advanced disease. Nearly all guideline-issuing bodies fail to provide race-specific recommendations, despite often acknowledging increased disease burden among non-whites.

CONCLUSION

Concerted efforts to overcome limitations in the generalizability of RCTs are required to provide screening guidelines that are truly applicable to non-white populations. Broader policy changes to improve the pipeline for minority populations into science and medicine are needed to address the ongoing lack of diversity in these fields.

Methylation of DROSHA and DICER as a Biomarker for the Detection of Lung Cancer

Simple Summary

To identify possible biomarkers for early detection of lung cancer we assessed the methylation status of genes related to carcinogenesis, DICER and DROSHA, in lung cancer patients and healthy volunteers. The relative level of methylation of DROSHA was significantly lower and DICER significantly higher in cancer patients. The relative level of methylation of DROSHA was significantly higher in patients with early-stage NSCLC (IA-IIIA) and could discriminate them from healthy people with a sensitivity of 71% and specificity of 76% for the first region and with a sensitivity of 60% and specificity of 85% for the second region. Analysis of the first region of the DICER enabled the distinction of NSCLC patients from healthy individuals with a sensitivity of 96% and specificity of 60%. The results indicate that the assessment of DICER and DROSHA methylation status can potentially be used as a biomarker for the early detection of lung cancer.

Abstract

Background: Lung cancer is the leading cause of cancer-related deaths. Early diagnosis may improve the prognosis. Methods: Using quantitative methylation-specific real-time PCR (qMSP-PCR), we assessed the methylation status of two genes (in two subsequent regions according to locations in their promoter sequences) related to carcinogenesis, DICER and DROSHA, in 101 plasma samples (obtained prior to the treatment) of lung cancer patients and 45 healthy volunteers. Results: The relative level of methylation of DROSHA was significantly lower (p = 0.012 for first and p < 0.00001 for the second region) and DICER significantly higher (p = 0.029 for the first region) in cancer patients. The relative level of methylation of DROSHA was significantly (p = 0.037) higher in patients with early-stage NSCLC (IA-IIIA) and could discriminate them from healthy people with a sensitivity of 71% and specificity of 76% (AUC = 0.696, 95% CI: 0.545–0.847, p = 0.011) for the first region and with a sensitivity of 60% and specificity of 85% (AUC = 0.795, 95% CI: 0.689–0.901, p < 0.0001) for the second region. Methylation analysis of the first region of the DICER enabled the distinction of NSCLC patients from healthy individuals with a sensitivity of 96% and specificity of 60% (AUC = 0.651, 95% CI: 0.517–0.785, p = 0.027). The limitations of the study include its small sample size, preliminary nature, being an observational type of study, and the lack of functional experiments allowing for the explanation of the biologic backgrounds of the observed associations. Conclusion: The obtained results indicate that the assessment of DICER and DROSHA methylation status can potentially be used as a biomarker for the early detection of lung cancer.

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.

9G TestTM Cancer/Lung: A Desirable Companion to LDCT for Lung Cancer Screening

Simple Summary

Lung cancer is the most common cause of cancer-related deaths globally. Patients diagnosed at early-stage (0–I) have a higher survival rate than the metastasized stages (III–IV). Thus, there is great potential to reduce mortality by diagnosing lung cancer at stage 0~I through community screening. LDCT is a promising method, but it has a high false-positive rate. Therefore, a biomarker test that can be used in combination with LDCT for lung cancer screening to reduce false-positive rates is highly awaited. The present study evaluated the applicability of 9G test^TM Cancer/Lung test to detect stage 0~IV lung cancer. 9G test^TM Cancer/Lung test detects stage I, stage II, stage III, and stage IV cancers with the sensitivities of 77.5%, 78.1%, 67.4%, and 33.3%, respectively, at the specificity of 97.3%. These results indicate that the 9G test^TM Cancer/Lung can be used in conjunction with LDCT to screen lung cancer.

Abstract

A complimentary biomarker test that can be used in combination with LDCT for lung cancer screening is highly desirable to improve the diagnostic capacity of LDCT and reduce the false-positive rates. Most importantly, the stage I lung cancer detection rate can be dramatically increased by the simultaneous use of a biomarker test with LDCT. The present study was conducted to evaluate 9G test^TM Cancer/Lung’s sensitivity and specificity in detecting Stage 0~IV lung cancer. The obtained results indicate that the 9G test^TM Cancer/Lung can detect lung cancer with overall sensitivity and specificity of 75.0% (69.1~80.3) and 97.3% (95.0~98.8), respectively. The detection of stage I, stage II, stage III, and stage IV cancers with sensitivities of 77.5%, 78.1%, 67.4%, and 33.3%, respectively, at the specificity of 97.3% have never been reported before. The receiver operating characteristic curve analysis allowed us to determine the population-weighted AUC of 0.93 (95% CI, 0.91–0.95). These results indicate that the 9G test^TM Cancer/Lung can be used in conjunction with LDCT to screen lung cancer. Furthermore, obtained results indicate that the use of 9G test^TM Cancer/Lung with LDCT for lung cancer screening can increase stage I cancer detection, which is crucial to improve the currently low 5-year survival rates.

The Evolution of Our Understanding of the Biology of Cancer Is the Key to Avoiding Overdiagnosis and Overtreatment

There has been a tremendous evolution in our thinking about cancer since the 1880s. Breast cancer is a particularly good example to evaluate the progress that has been made and the new challenges that have arisen due to screening that inadvertently identifies indolent lesions. The degree to which overdiagnosis is a problem depends on the reservoir of indolent disease, the disease heterogeneity, and the fraction of the tumors that have aggressive biology. Cancers span the spectrum of biological behavior, and population-wide screening increases the detection of tumors that may not cause harm within the patient's lifetime or may never metastasize or result in death. Our approach to early detection will be vastly improved if we understand, address, and adjust to tumor heterogeneity. In this article, we use breast cancer as a case study to demonstrate how the approach to biological characterization, diagnostics, and therapeutics can inform our approach to screening, early detection, and prevention. Overdiagnosis can be mitigated by developing diagnostics to identify indolent disease, incorporating biology and risk assessment in screening strategies, changing the pathology rules for tumor classification, and refining the way we classify precancerous lesions. The more the patterns of cancers can be seen across other cancers, the more it is clear that our approach should transcend organ of origin. This will be particularly helpful in advancing the field by changing both our terminology for what is cancer and also by helping us to learn how best to mitigate the risk of the most aggressive cancers.See all articles in this CEBP Focus section, "NCI Early Detection Research Network: Making Cancer Detection Possible."

Prognostic selection and long-term survival analysis to assess overdiagnosis risk in lung cancer screening randomized trials

OBJECTIVES

Overdiagnosis in low-dose computed tomography randomized screening trials varies from 0 to 67%. The National Lung Screening Trial (extended follow-up) and ITALUNG (Italian Lung Cancer Screening Trial) have reported cumulative incidence estimates at long-term follow-up showing low or no overdiagnosis. The Danish Lung Cancer Screening Trial attributed the high overdiagnosis estimate to a likely selection for risk of the active arm. Here, we applied a method already used in benefit and overdiagnosis assessments to compute the long-term survival rates in the ITALUNG arms in order to confirm incidence-excess method assessment.

METHODS

Subjects in the active arm were invited for four screening rounds, while controls were in usual care. Follow-up was extended to 11.3 years. Kaplan-Meyer 5- and 10-year survivals of "resected and early" (stage I or II and resected) and "unresected or late" (stage III or IV or not resected or unclassified) lung cancer cases were compared between arms.

RESULTS

The updated ITALUNG control arm cumulative incidence rate was lower than in the active arm, but this was not statistically significant (RR: 0.89; 95% CI: 0.67-1.18). A compensatory drop of late cases was observed after baseline screening. The proportion of "resected and early" cases was 38% and 19%, in the active and control arms, respectively. The 10-year survival rates were 64% and 60% in the active and control arms, respectively (p = 0.689). The five-year survival rates for "unresected or late" cases were 10% and 7% in the active and control arms, respectively (p = 0.679).

CONCLUSIONS

This long-term survival analysis, by prognostic categories, concluded against the long-term risk of overdiagnosis and contributed to revealing how screening works.

Exploring Novel Technologies in Lung Cancer Diagnosis: Do We Have Room for Improvement?

Lung cancer remains the leading cause of cancer-related death worldwide. Preventive strategies, mainly smoking cessation have a big impact on the reduction of lung cancer-related mortality. Screening with low dose computed tomography (LDCT) has proven to be beneficial in reducing the mortality related to lung cancer mainly based on early detection of cancer and timely initiation of treatment. Despite its beneficial effects, guideline-directed LDCT screening could lead to high false positive results, subjecting patients to harmful radiation, increase cost of healthcare and induce anxiety amongst the patients. Thus, it is imperative to look beyond the prevailing modalities of lung cancer screening and diagnosis to achieve better yield and mitigate the existent drawbacks.

High Aldehyde Dehydrogenase Levels Are Detectable in the Serum of Patients with Lung Cancer and May Be Exploited as Screening Biomarkers

Objectives

Since early detection improves overall survival in lung cancer, identification of screening biomarkers for patients at risk represents an area of intense investigation. Tumor liberated protein (TLP) has been previously described as a tumor-associated antigen (complex) present in the sera from lung cancer patients. Here, we set out to identify the nature of TLP to develop this as a potential biomarker for lung cancer screening.

Materials and Methods

Beginning from the peptide epitope RTNKEASI previously identified from the TLP complex, we produced a rabbit anti-RTNKEASI serum and evaluated it in the lung cancer cell line A549 by means of immunoblot and peptide completion assay (PCA). The TLP sequence identification was conducted by mass spectrometry. The detected protein was, then, analyzed in patients with non-small cell lung cancer (NSCLC) and benign lung pathologies and healthy donors, by ELISA.

Results

The anti-RTNKEASI antiserum detected and immunoprecipitated a 55 kDa protein band in the lysate of A549 cells identified as aldehyde dehydrogenase isoform 1A1, revealing the molecular nature of at least one component of the previously described TLP complex. Next, we screened blood samples from a non-tumor cohort of 26 patients and 45 NSCLC patients with different disease stages for the presence of ALDH1A1 and global ALDH. This analysis indicated that serum positivity was highly restricted to patients with NSCLC (ALDH p < 0.001; ALDH1A1 p=0.028). Interestingly, the global ALDH test resulted positive in more NSCLC samples compared to the ALDH1A1 test, suggesting that other ALDH isoforms might add to the sensitivity of the assay.

Conclusion

Our data indicate that ALDH levels are elevated in the sera of NSCLC patients, even with early stage disease, and may thus be evaluated as part of a marker panel for non-invasive detection of NSCLC.

A multi-parameterized artificial neural network for lung cancer risk prediction

The objective of this study is to train and validate a multi-parameterized artificial neural network (ANN) based on personal health information to predict lung cancer risk with high sensitivity and specificity. The 1997-2015 National Health Interview Survey adult data was used to train and validate our ANN, with inputs: gender, age, BMI, diabetes, smoking status, emphysema, asthma, race, Hispanic ethnicity, hypertension, heart diseases, vigorous exercise habits, and history of stroke. We identified 648 cancer and 488,418 non-cancer cases. For the training set the sensitivity was 79.8% (95% CI, 75.9%-83.6%), specificity was 79.9% (79.8%-80.1%), and AUC was 0.86 (0.85-0.88). For the validation set sensitivity was 75.3% (68.9%-81.6%), specificity was 80.6% (80.3%-80.8%), and AUC was 0.86 (0.84-0.89). Our results indicate that the use of an ANN based on personal health information gives high specificity and modest sensitivity for lung cancer detection, offering a cost-effective and non-invasive clinical tool for risk stratification.

The mapping of cancer incidence and mortality trends in the UK from 1980-2013 reveals a potential for overdiagnosis

The incidence of cancer in the United Kingdom has increased significantly over the last four decades. The aim of this study was to examine trends in UK cancer incidence and mortality by cancer site and assess the potential for overdiagnosis. Using Cancer Research UK incidence and mortality data for the period (1971–2014) we estimated percentage change in incidence and mortality rates and the incidence-mortality ratio (IMR) for cancers in which incidence had increased >50%. Incidence and mortality trend plots were used to assess the potential for overdiagnosis. Incidence rates increased from 67% (uterine) to 375% (melanoma). Change in mortality rates ranged from −69% (cervical) to +239% (liver). The greatest divergences occurred in uterine (IMR = 132), prostate (IMR = 9.6), oral (IMR = 9.8) and thyroid cancer (IMR = 5.3). Only in liver cancer did mortality track incidence (IMR = 1.1). For four cancer sites; uterine, prostate, oral and thyroid, incidence and mortality trends are suggestive of overdiagnosis. Trends in melanoma and kidney cancer suggest potential overdiagnosis and an underlying increase in true risk, whereas for cervical and breast cancer, trends may also reflect improvements in treatments or earlier diagnosis. A more detailed analysis is required to fully understand these patterns.

Challenges in Lung Cancer Screening in Latin America

Lung cancer is the deadliest cancer worldwide and is of particular concern for Latin America. Its rising incidence in this area of the world poses myriad challenges for the region's economies, which are already struggling with limited resources to meet the health care needs of low- and middle-income populations. In this environment, we are concerned that regional governments are relatively unaware of the pressing need to implement effective strategies for the near future. Low-dose chest computed tomography (LDCT) for screening, and routine use of minimally invasive techniques for diagnosis and staging remain uncommon. According to results of the National Lung Screening Trial, LDCT lung cancer screening provided a 20% relative reduction in mortality rates among at-risk individuals. Nevertheless, this issue is still a matter of debate, particularly in developing countries, and it is not fully embraced in developing countries. The aim of this article is to provide an overview of what the standard of care is for lung cancer computed tomography screening around the world and to aid understanding of the challenges and potential solutions that can help with the implementation of LDCT in Latin America.

Low-dose computed tomography (LDCT) versus other cancer screenings in early diagnosis of lung cancer: A meta-analysis

BACKGROUND

Lung cancer is the leading cause of cancer mortality worldwide. It is often diagnosed at an advanced stage when treatment is no longer possible. Early population-based screening may provide an opportunity for early diagnosis and reduce mortality rates.

METHODS

Study characteristics were collected and outcome data (lung cancer diagnosis and mortality) were extracted and used for meta-analysis. Statistical analyses were performed using OpenMetaAnalyst-0.1503 software. The odds ratio (OR) and 95% confidence interval (CI) were used to assess LDCT compared to other screening methods under the random-effects model. The I2 statistic was used to assess heterogeneity.

RESULTS

Pooling data from 4 studies (64,129 patients) showed a higher incidence of diagnosed lung cancer with LDCT screening (OR = 1.86, 95% CI: 1.02-3.37), compared to other screening tools. However, no significant difference (OR = 1.13, 95% CI: 0.78-1.64) was found in lung cancer mortality between both groups.

CONCLUSIONS

Although no significant difference was found between LDCT and other control groups in terms of lung cancer mortality, this meta-analysis suggests an increased diagnosis of lung cancer with LDCT as compared with other screening modalities. This meta-analysis displays the potential but also the limitations of LDCT for early lung cancer detection.

Benefits and Challenges of Lung Cancer Screening in Older Adults

PURPOSE

Lung cancer screening with low-dose computed tomography has been shown to significantly reduce lung cancer-related mortality in high-risk patients. However, patients diagnosed with lung cancer are typically older and often have multiple age- and smoking-related comorbidities. As a result, cancer screening in older adults remains a complex decision, requiring careful consideration of patients' risk characteristics and life expectancy to ensure that the benefits outweigh the risks of screening. In this review, we evaluate the evidence regarding lung cancer screening, with a focus on older patients.

METHODS

PubMed was searched to identify relevant studies evaluating the clinical outcomes of lung cancer screening. The key words used in our search included non-small cell lung cancer (NSCLC), screening, older, comorbidities, computed tomography, and survival. While we primarily looked for articles specific to older patients, we also focused on subgroup analysis in older patients in larger studies. Finally, we reviewed all relevant guidelines regarding lung cancer screening.

FINDINGS

Guidelines recommend that lung cancer screening be considered in adults aged 55 to 80 years who are at high risk based on smoking history (ie, 30-pack-year smoking history; having smoked within the past 15 years). Patients who fit these criteria have been shown to have a 20% reduction in lung cancer-related mortality with the use of low-dose computed tomography versus chest radiography. High rates of false-positive results and potential overdiagnoses were also observed. Therefore, screening is generally not recommended in adults with severe comorbidities or short life expectancy, who may experience limited benefit and higher risks with screening. However, several studies have shown a benefit with continued lung cancer screening with appropriate selection of older individuals at the highest risk and with the lowest comorbidities.

IMPLICATIONS

Older patients experience the highest risk for lung cancer incidence and mortality, and stand to be the most likely to benefit from lung cancer screening. However, careful consideration must be given to higher rates of false-positives and overdiagnosis in this population, as well as tolerability of surgery and competing risks for death from other causes. The appropriate selection of older individuals for lung cancer screening can be greatly optimized by using validated risk-based targeting.

Early Detection and Chemoprevention of Lung Cancer

Despite advances in targeted treatments, lung cancer remains a common and deadly malignancy, in part owing to its typical late presentation. Recent developments in lung cancer screening and ongoing efforts aimed at early detection, treatment, and prevention are promising areas to impact the mortality from lung cancer. In the past several years, lung cancer screening with low-dose chest computed tomography (CT) was shown to have mortality benefit, and lung cancer screening programs have been implemented in some clinical settings. Biomarkers for screening, diagnosis, and monitoring of response to therapy are under development. Prevention efforts aimed at smoking cessation are as crucial as ever, and there have been encouraging findings in recent clinical trials of lung cancer chemoprevention. Here we review advancements in the field of lung cancer prevention and early malignancy and discuss future directions that we believe will result in a reduction in the mortality from lung cancer.

Cell-Free DNA Quantification and Methylation Status of DCC Gene as Predictive Diagnostic Biomarkers of Lung Cancer in Patients Reported at Gulab Devi Chest Hospital, Lahore

The worldwide high mortality rate of lung cancer could be reduced significantly by its noninvasive early detection. The quantitative analysis of cell-free circulating DNA in plasma presents a potential noninvasive approach for liquid biopsy of tumor. In this study, real-time polymerase chain reaction–based approach was used to quantify free circulating DNA in plasma. The concentration of free circulating DNA was checked using human telomerase reverse transcriptase gene as marker, and amplification status of oncogene RAC-β serine/threonine protein kinase along with the DNA methylation status of tumor suppressor gene (deleted in colorectal cancer) was assessed. The concentration of free circulating DNA in patients with lung cancer (22.8 ng/mL) was found approximately 6 times above than the value detected in controls (2.8 ng/mL). Considerable variation in the AKT2 copy number was observed in patients with lung cancer and controls (P < .000). Aberrant methylation of the deleted in colorectal cancer promoter was found to be highly specific (100%), as none of the control plasma samples showed aberrant methylation. The quantification of free circulating DNA along with determination of AKT2 amplification and deleted in colorectal cancer promoter methylation status appeared promising to differentiate patients with lung cancer from healthy individuals.

Lung cancer screening

PURPOSE OF REVIEW

Lung cancer screening with low-dose chest computed tomography is now recommended for high-risk individuals by the US Preventive Services Task Force. This recommendation was informed by several randomized controlled trials, the largest of which, the National Lung Screening Trial, demonstrated a 20% relative reduction in lung cancer mortality with annual low-dose chest computed tomography compared with chest radiography.

RECENT FINDINGS

The benefit of lung cancer screening must be balanced against potential harms, including a high false-positive rate with consequent further evaluative studies and invasive testing. It is critical that harms be minimized as screening generalizes to the broad community. Informed decision making between providers and patients should include individualized risk assessment, a discussion of both potential benefit and harm, and tobacco treatment. Given the multiple components required for high quality, screening should ideally occur in the context of a multidisciplinary program.

SUMMARY

We are in the early days of lung cancer screening, still with much to learn. Ongoing studies are necessary to refine the definition of a positive screen and develop better methods of distinguishing between true positive and false-positive results. Novel approaches, including the development of multicomponent lung cancer biomarkers, will likely inform and improve our future screening practice.

The impact of overdiagnosis on the selection of efficient lung cancer screening strategies

The U.S. Preventive Services Task Force (USPSTF) recently updated their national lung screening guidelines and recommended low-dose computed tomography (LDCT) for lung cancer (LC) screening through age 80. However, the risk of overdiagnosis among older populations is a concern. Using four comparative models from the Cancer Intervention and Surveillance Modeling Network, we evaluate the overdiagnosis of the screening program recommended by USPSTF in the U.S. 1950 birth cohort. We estimate the number of LC deaths averted by screening (D) per overdiagnosed case (O), yielding the ratio D/O, to quantify the trade-off between the harms and benefits of LDCT. We analyze 576 hypothetical screening strategies that vary by age, smoking, and screening frequency and evaluate efficient screening strategies that maximize the D/O ratio and other metrics including D and life-years gained (LYG) per overdiagnosed case. The estimated D/O ratio for the USPSTF screening program is 2.85 (model range: 1.5-4.5) in the 1950 birth cohort, implying LDCT can prevent ∼3 LC deaths per overdiagnosed case. This D/O ratio increases by 22% when the program stops screening at an earlier age 75 instead of 80. Efficiency frontier analysis shows that while the most efficient screening strategies that maximize the mortality reduction (D) irrespective of overdiagnosis screen through age 80, screening strategies that stop at age 75 versus 80 produce greater efficiency in increasing life-years gained per overdiagnosed case. Given the risk of overdiagnosis with LC screening, the stopping age of screening merits further consideration when balancing benefits and harms.

HIV-Associated Lung Cancer

Lung cancer (LC) is one of the most common non-AIDS (acquired immune deficiency syndrome)-defining malignancies. It occurs more frequently in persons living with human immunodeficiency virus (PLWHIV) than in the HIV-negative population. Compared to their HIV-negative counterparts, patients are usually younger and diagnosed at more advanced stages. The pathogenesis of LC in PLWHIV is not fully understood, but immunosuppression in combination with chronic infection and the oncogenic effects of smoking and HIV itself all seem to play a role. Currently, no established preventive screening is available, making smoking cessation the most promising preventive measure. Treatment protocols and standards are the same as for the general population. Notably, immuno-oncology will also become standard of care in a significant subset of HIV-infected patients with LC. As drug interactions and hematological toxicity must be taken into account, a multidisciplinary approach should include a physician experienced in the treatment of HIV. Only limited data is available on novel targeted therapies and checkpoint inhibitors in the setting of HIV.

Lung cancer screening with low-dose CT in Europe: strength and weakness of diverse independent screening trials

A North American trial reported a significant reduction of lung cancer mortality and overall mortality as a result of annual screening using low-dose computed tomography (LDCT). European trials prospectively tested a variety of possible screening strategies. The main topics of current discussion regarding the optimal screening strategy are pre-test selection of the high-risk population, interval length of LDCT rounds, definition of positive finding, and post-test apportioning of lung cancer risk based on LDCT findings. Despite the current lack of statistical evidence regarding mortality reduction, the European independent diverse strategies offer a multi-perspective view on screening complexity, with remarkable indications for improvements in cost-effectiveness and harm-benefit balance. The UKLS trial reported the advantage of a comprehensive and simple risk model for selection of patients with 5% risk of lung cancer in 5 years. Subjective risk prediction by biological sampling is under investigation. The MILD trial reported equal efficiency for biennial and annual screening rounds, with a significant reduction in the total number of LDCT examinations. The NELSON trial introduced volumetric quantification of nodules at baseline and volume-doubling time (VDT) for assessment of progression. Post-test risk refinement based on LDCT findings (qualitative or quantitative) is under investigation. Smoking cessation remains the most appropriate strategy for mortality reduction, and it must therefore remain an integral component of any lung cancer screening programme.

Getting clearer on overdiagnosis

Overdiagnosis refers to diagnosis that does not benefit patients because the diagnosed condition is not a harmful disease in those individuals. Overdiagnosis has been identified as a problem in cancer screening, diseases such as chronic kidney disease and diabetes, and a range of mental illnesses including depression and attention deficit hyperactivity disorder. In this paper, we describe overdiagnosis, investigate reasons why it occurs, and propose two different types. Misclassification overdiagnosis arises because the diagnostic threshold for the disease in question has been set at a level where many people without harmful disease are nonetheless diagnosed. We illustrate misclassification overdiagnosis using the example of chronic kidney disease. Misclassification occurs in diseases diagnosed using biomarkers or based on patient reported phenomena. Maldetection overdiagnosis arises because, at the time the diagnosis is made and despite the presence of a 'gold standard' diagnostic test, it is not possible to discriminate between harmful and non-harmful cases of the index disease. We illustrate maldetection overdiagnosis using the example of thyroid cancer. While there is some overlap between misclassification and maldetection overdiagnosis, this conceptual analysis helps to clarify the phenomenon of overdiagnosis and is a necessary first step in developing strategies to address the problem.

Screening for lung cancer: A systematic review and meta-analysis

OBJECTIVES

To examine evidence on benefits and harms of screening average to high-risk adults for lung cancer using chest radiology (CXR), sputum cytology (SC) and low-dose computed tomography (LDCT).

METHODS

This systematic review was conducted to provide up to date evidence for Canadian Task Force on Preventive Health Care (CTFPHC) lung cancer screening guidelines. Four databases were searched to March 31, 2015 along with utilizing a previous Cochrane review search. Randomized trials reporting benefits were included; any design was included for harms. Meta-analyses were performed if possible. PROSPERO #CRD42014009984.

RESULTS

Thirty-four studies were included. For lung cancer mortality there was no benefit of CXR screening, with or without SC. Pooled results from three small trials comparing LDCT to usual care found no significant benefits for lung cancer mortality. One large high quality trial showed statistically significant reductions of 20% in lung cancer mortality over a follow-up of 6.5years, for LDCT compared with CXR. LDCT screening was associated with: overdiagnosis of 10.99-25.83%; 11.18 deaths and 52.03 patients with major complications per 1000 undergoing invasive follow-up procedures; median estimate for false positives of 25.53% for baseline/once-only screening and 23.28% for multiple rounds; and 9.74 and 5.28 individuals per 1000 screened, with benign conditions underwent minor and major invasive follow-up procedures.

CONCLUSION

The evidence does not support CXR screening with or without sputum cytology for lung cancer. High quality evidence showed that in selected high-risk individuals, LDCT screening significantly reduced lung cancer mortality and all-cause mortality. However, for its implementation at a population level, the current evidence warrants the development of standardized practices for screening with LDCT and follow-up invasive testing to maximize accuracy and reduce potential associated harms.

Executive summary of the SEPAR recommendations for the diagnosis and treatment of non-small cell lung cancer

The Thoracic Surgery and Thoracic Oncology groups of the Spanish Society of Pulmonology and Thoracic Surgery (SEPAR) have backed the publication of a handbook on recommendations for the diagnosis and treatment of non-small cell lung cancer. Due to the high incidence and mortality of this disease, the best scientific evidence must be constantly updated and made available for consultation by healthcare professionals. To draw up these recommendations, we called on a wide-ranging group of experts from the different specialties, who have prepared a comprehensive review, divided into 4 main sections. The first addresses disease prevention and screening, including risk factors, the role of smoking cessation, and screening programs for early diagnosis. The second section analyzes clinical presentation, imaging studies, and surgical risk, including cardiological risk and the evaluation of respiratory function. The third section addresses cytohistological confirmation and staging studies, and scrutinizes the TNM and histological classifications, non-invasive and minimally invasive sampling methods, and surgical techniques for diagnosis and staging. The fourth and final section looks at different therapeutic aspects, such as the role of surgery, chemotherapy, radiation therapy, a multidisciplinary approach according to disease stage, and other specifically targeted treatments, concluding with recommendations on the follow-up of lung cancer patients and surgical and endoscopic palliative interventions in advanced stages.

Observation versus Resection for Small Asymptomatic Pancreatic Neuroendocrine Tumors: A Matched Case-Control Study

OBJECTIVE

To analyze the natural history of small asymptomatic pancreatic neuroendocrine tumors (PanNET) and to present a matched comparison between groups who underwent either initial observation or resection. Management approach for small PanNET is uncertain.

METHODS

Incidentally discovered, sporadic, small (<3 cm), stage I-II PanNET were analyzed retrospectively between 1993 and 2013. Diagnosis was determined either by pathology or imaging characteristics. Intention-to-treat analysis was applied.

RESULTS

A total of 464 patients were reviewed. Observation was recommended for 104 patients (observation group), and these patients were matched to 77 patients in the resection group based on tumor size at initial imaging. The observation group was significantly older (median 63 vs. 59 years, p = 0.04) and tended towards shorter follow-up (44 vs. 57 months, p = 0.06). Within the observation group, 26 of the 104 patients (25 %) underwent subsequent tumor resection after a median observation interval of 30 months (range 7-135). At the time of last follow-up of the observation group, the median tumor size had not changed (1.2 cm, p = 0.7), and no patient had developed evidence of metastases. Within the resection group, low-grade (G1) pathology was recorded in 72 (95 %) tumors and 5 (6 %) developed a recurrence, which occurred after a median of 5.1 (range 2.9-8.1) years. No patient in either group died from disease. Death from other causes occurred in 11 of 181 (6 %) patients.

CONCLUSIONS

In this study, no patient who was initially observed developed metastases or died from disease after a median follow-up of 44 months. Observation for stable, small, incidentally discovered PanNET is reasonable in selected patients.

Lung Cancer Screening

Lung cancer is the leading cause of cancer mortality in the United States and worldwide. Since lung cancer outcomes are dependent on stage at diagnosis with early disease resulting in longer survival, the goal of screening is to capture lung cancer in its early stages when it can be treated and cured. Multiple studies have evaluated the use of chest X-ray (CXR) with or without sputum cytologic examination for lung cancer screening, but none has demonstrated a mortality benefit. In contrast, the multicenter National Lung Screening Trial (NLST) from the United States found a 20 % reduction in lung cancer mortality following three consecutive screenings with low-dose computed tomography (LDCT) in high-risk current and former smokers. Data from European trials are not yet available. In addition to a mortality benefit, lung cancer screening with LDCT also offers a unique opportunity to promote smoking cessation and abstinence and may lead to the diagnoses of treatable chronic diseases, thus decreasing the overall disease burden. The risks of lung cancer screening include overdiagnosis, radiation exposure, and false-positive results leading to unnecessary testing and possible patient anxiety and distress. However, the reduction in lung cancer mortality is a benefit that outweighs the risks and major health organizations currently recommend lung cancer screening using age, smoking history, and quit time criteria derived from the NLST. Although more research is needed to clearly define and understand the application and utility of lung cancer screening in the general population, current data support that lung cancer screening is effective and should be offered to eligible beneficiaries.

Lung Cancer Screening

Screening for lung cancer in high-risk individuals with annual low-dose computed tomography has been shown to reduce lung cancer mortality by 20% and is recommended by multiple health care organizations. Lung cancer screening is not a specific test; it is a process that involves appropriate selection of high-risk individuals, careful interpretation and follow-up of imaging, and annual testing. Screening should be performed in the context of a multidisciplinary program experienced in the diagnosis and management of lung nodules and early-stage lung cancer.

Long-Term Follow-up Results of the DANTE Trial, a Randomized Study of Lung Cancer Screening with Spiral Computed Tomography

RATIONALE

Screening for lung cancer with low-dose spiral computed tomography (LDCT) has been shown to reduce lung cancer mortality by 20% compared with screening with chest X-ray (CXR) in the National Lung Screening Trial, but uncertainty remains concerning the efficacy of LDCT screening in a community setting.

OBJECTIVES

To explore the effect of LDCT screening on lung cancer mortality compared with no screening. Secondary endpoints included incidence, stage, and resectability rates.

METHODS

Male smokers of 20+ pack-years, aged 60 to 74 years, underwent a baseline CXR and sputum cytology examination and received five screening rounds with LDCT or a yearly clinical review only in a randomized fashion.

MEASUREMENTS AND MAIN RESULTS

A total of 1,264 subjects were enrolled in the LDCT arm and 1,186 in the control arm. Their median age was 64.0 years (interquartile range, 5), and median smoking exposure was 45.0 pack-years. The median follow-up was 8.35 years. One hundred four patients (8.23%) were diagnosed with lung cancer in the screening arm (66 by CT), 47 of whom (3.71%) had stage I disease; 72 control patients (6.07%) were diagnosed with lung cancer, with 16 (1.35%) being stage I cases. Lung cancer mortality was 543 per 100,000 person-years (95% confidence interval, 413-700) in the LDCT arm versus 544 per 100,000 person-years (95% CI, 410-709) in the control arm (hazard ratio, 0.993; 95% confidence interval, 0.688-1.433).

CONCLUSIONS

Because of its limited statistical power, the results of the DANTE (Detection And screening of early lung cancer with Novel imaging TEchnology) trial do not allow us to make a definitive statement about the efficacy of LDCT screening. However, they underline the importance of obtaining additional data from randomized trials with intervention-free reference arms before the implementation of population screening.

Gene Signatures Stratify Computed Tomography Screening Detected Lung Cancer in High-Risk Populations

BACKGROUND

Although screening programmes of smokers have detected resectable early lung cancers more frequently than expected, their efficacy in reducing mortality remains debatable. To elucidate the biological features of computed tomography (CT) screening detected lung cancer, we examined the mRNA signatures on tumours according to the year of detection, stage and survival.

METHODS

Gene expression profiles were analysed on 28 patients (INT-IEO training cohort) and 24 patients of Multicentre Italian Lung Detection (MILD validation cohort). The gene signatures generated from the training set were validated on the MILD set and a public deposited DNA microarray data set (GSE11969). Expression of selected genes and proteins was validated by real-time RT-PCR and immunohistochemistry. Enriched core pathway and pathway networks were explored by GeneSpring GX10.

FINDINGS

A 239-gene signature was identified according to the year of tumour detection in the training INT-IEO set and correlated with the patients' outcomes. These signatures divided the MILD patients into two distinct survival groups independently of tumour stage, size, histopathological type and screening year. The signatures can also predict survival in the clinically detected cancers (GSE11969). Pathway analyses revealed tumours detected in later years enrichment of the PI3K/PTEN/AKT pathway, with up-regulation of PDPK1, ITGB1 and down-regulation of FOXO1A. Analysis of normal lung tissue from INT-IEO cohort produced signatures distinguishing patients with early from late detected tumours.

INTERPRETATION

The distinct pattern of "indolent" and "aggressive" tumour exists in CT-screening detected lung cancer according to the gene expression profiles. The early development of an aggressive phenotype may account for the lack of mortality reduction by screening observed in some cohorts.

Bilateral Adrenal Incidentalomas: A Rare Presentation of Lung Cancer

Adrenal incidentalomas are found incidentally during a radiologic examination performed for indications other than an adrenal disease, and 15% of them are bilateral adrenal masses. This study describes a 51-year-old male smoker patient admitted with diabetes mellitus. An abdominal ultrasonography performed due to his anemia revealed bilateral adrenal masses. His chest X-ray showed abnormal 10 cm opacity at the right upper lung, and brain, thorax, and abdomen CT scans showed multiple lesions compatible with lung cancer metastases. The pathological examination of the transthoracic lung biopsy specimen was consistent with lung adenocarcinoma. Findings in this patient indicate that, in middle aged patients with bilateral adrenal mass and a history or finding of any malignancy, the first diagnosis which should be considered is adrenal metastasis, and confirming the diagnosis by adrenal biopsy may be useless. Furthermore, screening all smoking patients by chest X-ray or thoracic CT for lung cancer may not be accepted as a routine procedure, but in smokers admitted to a hospital due to signs and symptoms attributed to a pulmonary disease, at least a chest X-ray should be requested.

Diminished Disease-Free Survival After Lobectomy: Screening Implications

BACKGROUND

The aim of this study was to estimate the effect of lobectomy on life expectancy in healthy smokers and consider the implications for lung cancer screening.

MATERIALS AND METHODS

In a retrospective cohort study that provided a minimum of 15 years of follow-up, we analyzed lung cancer survival, all-cause survival, and fatality (1-survival) of 261 persons with stage I non-small-cell lung cancer who underwent lobectomy at Portland Providence Medical Center between 1978 and 1994. We: (1) compared 5-year disease-free fatality (non-lung-cancer fatality) with lung cancer fatality; and (2) based on actuarial data that demonstrated life expectancy equivalence of the healthiest smokers (whom we assumed would be comparable with subjects judged eligible for lobectomy) in the US population, we compared their long-term, disease-free survival (our primary end point) with actuarial expectations by computing the Kaplan-Meier survival function of the differences between lifetimes since surgery in disease-free persons versus matched, expected remaining lifetimes in the US population.

RESULTS

(1) Five-year disease-free fatality (16.1%) was 58% as high as 5-year lung cancer fatality (27.6%); (2) disease-free survival was reduced by 6.9-years (95% confidence interval, 5.5-8.3), 41% of actuarial life expectancy (17 years). The divergence from expected survival took place largely after 6 years of follow-up.

CONCLUSION

Lobectomy materially diminishes long-term disease-free survival in the healthiest smokers--persons judged healthy enough to tolerate major surgery and to have sufficient pulmonary reserve to sustain loss of one-fifth of their lung tissue. In screened populations, diminished survival in overdiagnosed persons will offset, to an undetermined extent, the mortality benefit imparted by preemption of advanced lung cancer.

Lung cancer screening

The United States Preventive Services Task Force recommends lung cancer screening with low-dose computed tomography (LDCT) in adults of age 55 to 80 years who have a 30 pack-year smoking history and are currently smoking or have quit within the past 15 years. This recommendation is largely based on the findings of the National Lung Screening Trial. Both policy-level and clinical decision-making about LDCT screening must consider the potential benefits of screening (reduced mortality from lung cancer) and possible harms. Effective screening requires an appreciation that screening should be limited to individuals at high risk of death from lung cancer, and that the risk of harm related to false positive findings, overdiagnosis, and unnecessary invasive testing is real. A comprehensive understanding of these aspects of screening will inform appropriate implementation, with the objective that an evidence-based and systematic approach to screening will help to reduce the enormous mortality burden of lung cancer.