Radiation Risk of Lung Cancer Screening

Screening for Lung Cancer: CHEST Guideline and Expert Panel Report

BACKGROUND

Low-dose chest CT screening for lung cancer has become a standard of care in the United States, in large part because of the results of the National Lung Screening Trial (NLST). Additional evidence supporting the net benefit of low-dose chest CT screening for lung cancer, and increased experience in minimizing the potential harms, has accumulated since the prior iteration of these guidelines. Here, we update the evidence base for the benefit, harms, and implementation of low-dose chest CT screening. We use the updated evidence base to provide recommendations where the evidence allows, and statements based on experience and expert consensus where it does not.

METHODS

Approved panelists reviewed previously developed key questions using the Population, Intervention, Comparator, Outcome format to address the benefit and harms of low-dose CT screening, and key areas of program implementation. A systematic literature review was conducted using MEDLINE via PubMed, Embase, and the Cochrane Library on a quarterly basis since the time of the previous guideline publication. Reference lists from relevant retrievals were searched, and additional papers were added. Retrieved references were reviewed for relevance by two panel members. The quality of the evidence was assessed for each critical or important outcome of interest using the Grading of Recommendations, Assessment, Development, and Evaluation approach. Meta-analyses were performed when enough evidence was available. Important clinical questions were addressed based on the evidence developed from the systematic literature review. Graded recommendations and ungraded statements were drafted, voted on, and revised until consensus was reached.

RESULTS

The systematic literature review identified 75 additional studies that informed the response to the 12 key questions that were developed. Additional clinical questions were addressed resulting in seven graded recommendations and nine ungraded consensus statements.

CONCLUSIONS

Evidence suggests that low-dose CT screening for lung cancer can result in a favorable balance of benefit and harms. The selection of screen-eligible individuals, the quality of imaging and image interpretation, the management of screen-detected findings, and the effectiveness of smoking cessation interventions can impact this balance.

Women and Lung Cancer

The world is witnessing a global epidemic of lung cancer in women. Cigarette smoking remains the dominant risk factor in both sexes, but multiple observations suggest that important sex-related distinctions in lung cancer exist. These include differences in histologic distribution, prevalence in never-smokers, frequency of activating EGFR mutations, likelihood of DNA adduct accumulation, and survival outcomes. Important questions such as whether women are more susceptible to carcinogenic effects of smoking or derive more benefit from lung cancer screening merit more study. A deeper understanding of sex-related differences in lung cancer may lead to improved outcomes for both women and men.

Lung cancer screening in Australia and New Zealand: the evidence and the challenge

Lung cancer remains the commonest cause of cancer death in Australia and New Zealand. Targeted screening of individuals at highest risk of lung cancer aims to detect early stage disease, which may be amenable to potentially curative treatment. While current policy recommendations in Australia and New Zealand have acknowledged the efficacy of lung cancer screening in clinical trials, there has been no implementation of national programmes. With the recent release of findings from large international trials, the evidence and experience in lung cancer screening has broadened. This article discusses the latest evidence and implications for Australia and New Zealand.

BATF acts as an oncogene in non-small cell lung cancer

One of the main causes of cancer incidence and mortality worldwide is lung cancer. This study focused on the function of basic leucine zipper ATF-like transcription factor (BATF) in non-small cell lung cancer (NSCLC). Using NSCLC patient data from The Cancer Genome Atlas, the present study demonstrated that BATF expression in NSCLC tissues was significantly higher compared with that in adjacent non-tumor tissues (P=6.56×10⁻⁶). Lentivirus-mediated short hairpin RNA (shRNA) was used to knock down BATF expression in the human A549 NSCLC cell line and assessed by reverse transcription-quantitative PCR and western blotting. Cell proliferation was evaluated by MTT assay and Celigo imaging cytometry. Apoptosis was detected by fluorescence-activated cell sorting and caspase 3/7 activity analysis. The results revealed that knockdown of BATF inhibited the proliferation of A549 cells. Compared with that of the control group, the apoptosis rate of the BATF-shRNA group was significantly higher. In summary, knockdown of BATF inhibited the proliferation of A549 cells and promoted apoptosis. These results provide important information about the underlying mechanism of the pathogenesis of NSCLC.

KIAA1211 plays an oncogenic role in human non-small cell lung cancer

One of the main causes of cancer disease and death worldwide is lung cancer. Our study focused on the function of KIAA1211 in non-small cell lung cancer (NSCLC). According to the data about NSCLC patients that from the Cancer Genome Atlas (TCGA), we found that KIAA1211 in NSCLC (P=5.06E-06) was significantly higher than the adjacent normal. Lentivirus-mediated short hairpin RNA (shRNA) was used to knockdown BATF expression in the human A549 NSCLC cell line and assessed by RT-qPCR and Western blot. Cell proliferation was evaluated by MTT assay and Celigo imaging cytometry. Cell apoptosis were detected by Annexin V staining. The test results showed that KIAA1211-shRNA A549 and SPC-A-1 cells can inhibit cell proliferation, and the apoptosis rate of KIAA1211-shRNA group was significantly higher than that of the control group. Knockdown of KIAA1211 inhibited NSCLC progression in xenograft tumor model. In conclusion, KIAA1211 could regulate NSCLC cells proliferation and apoptosis in vitro and in vivo. KIAA1211 may serve as a potent target for the treatment of NSCLC.

Lung Cancer Screening, Version 3.2018, NCCN Clinical Practice Guidelines in Oncology

Lung cancer is the leading cause of cancer-related mortality in the United States and worldwide. Early detection of lung cancer is an important opportunity for decreasing mortality. Data support using low-dose computed tomography (LDCT) of the chest to screen select patients who are at high risk for lung cancer. Lung screening is covered under the Affordable Care Act for individuals with high-risk factors. The Centers for Medicare & Medicaid Services (CMS) covers annual screening LDCT for appropriate Medicare beneficiaries at high risk for lung cancer if they also receive counseling and participate in shared decision-making before screening. The complete version of the NCCN Guidelines for Lung Cancer Screening provides recommendations for initial and subsequent LDCT screening and provides more detail about LDCT screening. This manuscript focuses on identifying patients at high risk for lung cancer who are candidates for LDCT of the chest and on evaluating initial screening findings.

Reviewing Lung Cancer Screening: The Who, Where, When, Why, and How

Lung cancer screening with annual low-dose computed tomography (CT) decreases lung cancer mortality in high-risk patients, as defined by smoking history (> 30 pack-years) and age (55-74 years). Risks to screening include overdiagnosis, anxiety about indeterminate nodules, and radiation exposure. To be effective, lung cancer screening must combine individualized risk assessment, shared decision-making, smoking cessation, structured reporting, high quality and multi-specialty cancer care, and reliable follow-up; a multidisciplinary approach is crucial. Specialty organizations have outlined both the components of high quality lung cancer screening programs and the proposed metrics that programs should track. Long-term outcomes of lung cancer screening in the general population, further refinement of who to screen, and use of biomarkers for early cancer detection are ongoing research questions.

Barriers to Lung Cancer Screening Engagement from the Patient and Provider Perspective

Lung cancer remains the leading cause of cancer mortality in the United States. Lung cancer screening (LCS) with low-dose CT reduces mortality among high-risk current and former smokers and has been covered by public and private insurers without cost sharing since 2015. Patients and referring providers confront numerous barriers to participation in screening. To best serve in multidisciplinary efforts to expand LCS nationwide, radiologists must be knowledgeable of these challenges. A better understanding of the difficulties confronted by other stakeholders will help radiologists continue to collaboratively guide the growth of LCS programs in their communities. This article reviews barriers to participation in LCS for patients and referring providers, as well as possible solutions and interventions currently underway.

Screening for Lung Cancer: CHEST Guideline and Expert Panel Report

BACKGROUND

Low-dose chest CT screening for lung cancer has become a standard of care in the United States in the past few years, in large part due to the results of the National Lung Screening Trial. The benefit and harms of low-dose chest CT screening differ in both frequency and magnitude. The translation of a favorable balance of benefit and harms into practice can be difficult. Here, we update the evidence base for the benefit, harms, and implementation of low radiation dose chest CT screening. We use the updated evidence base to provide recommendations where the evidence allows, and statements based on experience and expert consensus where it does not.

METHODS

Approved panelists developed key questions using the PICO (population, intervention, comparator, and outcome) format to address the benefit and harms of low-dose CT screening, as well as key areas of program implementation. A systematic literature review was conducted by using MEDLINE via PubMed, Embase, and the Cochrane Library. Reference lists from relevant retrievals were searched, and additional papers were added. The quality of the evidence was assessed for each critical or important outcome of interest using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach. Important clinical questions were addressed based on the evidence developed from the systematic literature review. Graded recommendations and ungraded statements were drafted, voted on, and revised until consensus was reached.

RESULTS

The systematic literature review identified 59 studies that informed the response to the 12 PICO questions that were developed. Key clinical questions were addressed resulting in six graded recommendations and nine ungraded consensus based statements.

CONCLUSIONS

Evidence suggests that low-dose CT screening for lung cancer results in a favorable but tenuous balance of benefit and harms. The selection of screen-eligible patients, the quality of imaging and image interpretation, the management of screen-detected findings, and the effectiveness of smoking cessation interventions can affect this balance. Additional research is needed to optimize the approach to low-dose CT screening.

Lung cancer: current therapies and new targeted treatments

Lung cancer is the most frequent cause of cancer-related deaths worldwide. Every year, 1·8 million people are diagnosed with lung cancer, and 1·6 million people die as a result of the disease. 5-year survival rates vary from 4-17% depending on stage and regional differences. In this Seminar, we discuss existing treatment for patients with lung cancer and the promise of precision medicine, with special emphasis on new targeted therapies. Some subgroups, eg-patients with poor performance status and elderly patients-are not specifically addressed, because these groups require special treatment considerations and no frameworks have been established in terms of new targeted therapies. We discuss prevention and early detection of lung cancer with an emphasis on lung cancer screening. Although we acknowledge the importance of smoking prevention and cessation, this is a large topic beyond the scope of this Seminar.

The effect of direct access to CT scan in early lung cancer detection: an unblinded, cluster-randomised trial

Background

Lower lung cancer survival rates in Britain and Denmark compared with surrounding countries may, in part, be due to late diagnosis. The aim of this study was to evaluate the effect of direct access to low-dose computed tomography (LDCT) from general practice in early lung cancer detection on time to diagnosis and stage at diagnosis.

Methods

We conducted a cluster-randomised, controlled trial including all incident lung cancer patients (in 19-month period) listed with general practice in the municipality of Aarhus (300,000 citizens), Denmark. Randomisation and intervention were applied at general practice level. A total of 266 GPs from 119 general practices. In the study period, 331 lung cancer patients were included. The intervention included direct access to low-dose CT from primary care combined with a 1 h lung cancer update meeting. Indication for LDCT was symptoms or signs that raised the GP’s suspicion of lung cancer, but fell short of satisfying the fast-track referral criteria on red flag’ symptoms.

Results

The intervention did not significantly influence stage at diagnosis and had limited impact on time to diagnosis. However, when correcting for non-compliance, we found that the patients were at higher risk of experiencing a long diagnostic interval if their GPs were in the control group.

Conclusion

Direct low-dose CT from primary care did not statistically significantly decrease time to diagnosis or change stage at diagnosis in lung cancer patients. Case finding with direct access to LDCT may be an alternative to lung cancer screening. Furthermore, a recommendation of low-dose CT screening should consider offering symptomatic, unscreened patients an access to CT directly from primary care.

Trial registration

www.clinicaltrials.gov, registration ID number NCT01527214.

Interleukin 17A genetic variations and susceptibility to non-small cell lung cancer

Lung cancer is the leading cause of cancer-related death, in which non-small cell lung cancer (NSCLC) is the most common type. Evidence have shown that interleukin 17 (IL-17) greatly involves in human immune responses. In this study, we investigated the effect of IL-17 on NSCLC by examining the association between IL-17A genetic polymorphisms and the susceptibility to NSCLC. IL-17A -420A/G and IL-17A -73G/A polymorphisms were detected in 330 NSCLC patients and 382 healthy controls. We found that subjects carrying -73GA genotype or AA genotype had 2.09-fold or 2.52-fold increased risk of NSCLC than those with -73GG genotype [odds ratio (OR) = 2.09, 95% confidence interval (CI), 1.46 - 2.98, p < 0.001; OR = 2.52, 95% CI, 1.30-4.88, p = 0.005, respectively). However, the IL-17A -420A/G did not reveal any correlation with the cancer. Further investigation showed that prevalence of IL-17A -73GA genotype and A allele were significantly increased in adenocarcinoma patients (OR = 1.75, 95% CI, 1.08-2.86, p = 0.024, OR = 1.57, 95% CI, 1.09-2.28, p = 0.016, respectively). We also evaluated the effect of the polymorphisms on gene expression, and identified that peripheral blood mononuclear cells with IL-17A -73GA and AA genotypes produced significantly higher level of IL-17 than the cells with IL-17A -73GG genotype. Our results suggest that IL-17A -73G/A genetic variations may upregulate IL-17 expression and are associated with increased susceptibility to NSCLC.

Assessing the benefits and harms of low-dose computed tomography screening for lung cancer

The concept of using low-dose computed tomography (LDCT) for lung cancer screening goes back almost 25 years. In 2011, the National Lung Screening Trial (NLST) reported that LDCT screening significantly reduced mortality from lung cancer in a high risk population. This article evaluates the benefits and harms of LDCT screening, based largely on evidence from randomized trials. Harms include false-positive screens and resultant diagnostic procedures, overdiagnosed cancers, and radiation exposure. Benefits can be expressed as the number needed to be screened to prevent one lung cancer death or as estimated overall reductions in lung cancer mortality assuming LDCT population screening as recommended by guidelines. Indirect metrics of benefit, such as lung cancer survival and stage distribution, as well as measures of harms, will be important to monitor in the future as LDCT screening disseminates in the population.

Implementing direct access to low-dose computed tomography in general practice--method, adaption and outcome

BACKGROUND

Early detection of lung cancer is crucial as the prognosis depends on the disease stage. Chest radiographs has been the principal diagnostic tool for general practitioners (GPs), but implies a potential risk of false negative results, while computed tomography (CT) has a higher sensitivity. The aim of this study was to describe the implementation of direct access to low-dose CT (LDCT) from general practice.

METHODS

We conducted a cohort study nested in a randomised study. A total of 119 general practices with 266 GPs were randomised into two groups. Intervention GPs were offered direct access to chest LDCT combined with a Continuing Medical Education (CME) meeting on lung cancer diagnosis.

RESULTS

During a 19-month period, 648 patients were referred to LDCT (0.18/1000 adults on GP list/month). Half of the patients needed further diagnostic work-up, and 15 (2.3%, 95% CI: 1.3-3.8%) of the patients had lung cancer; 60% (95% CI: 32.3-83.7%) in a localised stage. The GP referral rate was 61% higher for CME participants compared to non-participants.

CONCLUSION

Of all patients referred to LDCT, 2.3% were diagnosed with lung cancer with a favourable stage distribution. Half of the referred patients needed additional diagnostic work-up. There was an association between participation in CME and use of CT scan. The proportion of cancers diagnosed through the usual fast-track evaluation was 2.2 times higher in the group of CME-participating GPs. The question remains if primary care case-finding with LDCT is a better option for patients having signs and symptoms indicating lung cancer than a screening program. Whether open access to LDCT may provide earlier diagnosis of lung cancer is yet unknown and a randomised trial is required to assess any effect on outcome.

TRIAL REGISTRATION

Clinicaltrials.gov NCT01527214.

Issues with implementing a high-quality lung cancer screening program

After a comprehensive review of the evidence, the United States Preventive Services Task Force recently endorsed screening with low-dose computed tomography as an early detection approach that has the potential to significantly reduce deaths due to lung cancer. Prudent implementation of lung cancer screening as a high-quality preventive health service is a complex challenge. The clinical evaluation and management of high-risk cohorts in the absence of symptoms mandates an approach that differs significantly from that of symptom-detected lung cancer. As with other cancer screenings, it is essential to provide to informed at-risk individuals a safe, high-quality, cost-effective, and accessible service. In this review, the components of a successful screening program are discussed as we begin to disseminate lung cancer screening as a national resource to improve outcomes with this lethal cancer. This information about lung cancer screening will assist clinicians with communications about the potential benefits and harms of this service for high-risk individuals considering participation in the screening process.