Screening of smoke-induced pulmonary diseases. Should smokers be made aware?| Rassegna di Patologia dell'Apparato Respiratorio

Abstract

Chronic Obstructive Pulmonary Disease (COPD) and Lung Cancer (LC) are the most important consequences of smoking. Very little has been done in terms of secondary prevention against COPD and LC. Concerning COPD, all smokers at increased risk (aged > 40-50 years) should do an annual spirometry aiming at diagnosing the initial stages of the disease. In addition, we might suggest that all smokers aged > 40-50 years, waiting for LDCT (Low Dose Computed Tomography) to be confirmed and validated, should perform a chest X-ray (CXR) for an early LC diagnosis. Although this exam has a very low sensitivity to detect LC, it may be a temporary alternative if applied on a large scale. Certainly, LDCT screening has proved to reduce lung cancer and all-cause mortality. Moreover, it will soon be available in certified multidisciplinary medical centers for smokers aged between 55 and 80 years (≥ 30 pack-years) and ex-smokers who have quit smoking during the last 15 years. These tests might lead to a significant increase of an early COPD/LC diagnosis with a reduction of management costs. Furthermore, screening may also induce quitting smoking. Therefore, all smokers aged > 40-55 years should be made aware of the possibility to effect a screening of smoke-induced pulmonary diseases, through an annual spirometry and CXR or better, by LDCT. Cigarette packaging messages, media propaganda, health policy and scientific societies programs are supposed to stimulate smokers to perform a COPD/LC screening. A screening strategy, aimed at all smokers, rather than only symptomatic smokers, may have a great impact on public health. However, nowadays the best way to reduce the risk of smoke-induced diseases is still “quitting smoking”, which can be achieved by increasing the knowledge of smoking-induced diseases.

Introduction

Chronic Obstructive Pulmonary Disease (COPD) and Lung Cancer (LC) are the most important smoke-induced diseases. Approximately 10-15% of smokers aged > 40 years develops COPD ¹, whereas 80-90% of 1.61 million of LC new cases in Europe (in 2008) is induced by smoking ^{2 3}. An increased risk for the development of these diseases appears to be related to the number of packets/year of cigarettes smoked ^{4 5}, therefore specific educational smoking cessation programs are urgently needed to reduce smoking-related premature deaths. In fact, smoking cessation immediately reduces the risk of cardiovascular diseases, cancer and all cause-mortality effectively ^4-7. The most important interventions of primary prevention against smoking are health warnings and shocking pictures on cigarette packaging communicating the risk. All of them have shown to be somewhat effective for smoking cessation ^8-14 and they have also helped not to start smoking at all ^{8 15-17}.

Little effort has been made in terms of secondary prevention interventions focused on detecting early smoking-induced respiratory diseases in current smokers.

Unfortunately, these messages are not always helpful. In fact, despite all these warnings, millions of people continue/start such habit ¹⁸. Furthermore, nowadays, little effort has been made in terms of secondary prevention interventions focused on detecting early smoking-induced respiratory diseases (COPD and LC) in current smokers. In particular, smokers are not always aware of the possibility to perform exams to diagnose pulmonary diseases precociously. On the other hand, there are no precise health programs that may induce smokers to perform a screening.

Stimulating all smokers at risk to be screened may also be effective in terms of public health.

Encouraging smokers aged > 40-50 years to perform spirometry

Spirometry allows us to make an airway obstruction diagnosis characterizing COPD. This test, as everybody knows, is simple, cheap and available worldwide, therefore can be the ideal exam to effect a COPD screening. For this reason, it would be advisable to persuade all smokers aged > 40 years to perform an annual spirometry.

Spirometry is simple, cheap and available worldwide, therefore it would be advisable to persuade all smokers aged > 40 years to perform an annual spirometry.

Unfortunately, today, it is still rarely suggested to perform such a test. In fact, as there are about 1 billion smokers all over the world, if one out of 1.000/year performed this test, we might precociously diagnose COPD for about 130.000-250.000 subjects/year.

Nowadays, over 70-80% mild/moderate COPD remains undiagnosed. Only in 13-25% of non-symptomatic smokers (aged > 45 years) is COPD diagnosed after a spirometry and 80-90% of them show a mild/moderate COPD ^19-22. In fact, only symptomatic smokers go to doctors (in particular to GPs) who might advise them to perform a spirometry. They are often over 60-65 years when COPD is diagnosed and therefore it is at a moderate/severe stage. A late diagnosis implies higher costs (for severe COPD management) compared to a diagnosis at the initial stages. Early COPD treatment is likely to slow disease progression. Accumulating data from placebo-controlled trials showed that long-acting bronchodilators can slow lung function decline, reduce exacerbations and mortality rates and improve health-related quality of life in patients with mild-to-moderate COPD ²³. This is why all smokers aged over 40 (risk age) should perform an annual spirometry in spite of symptoms.

Unfortunately, today many smokers do not know what COPD and spirometry are. Therefore, one of the most important purposes of scientific societies, Health Policy (through mass media) and doctors should be to make smokers aware about such issues. In this way, they would know not only that there is a severe, destructive and progressive pulmonary disease called COPD and a test to diagnose it precociously, but also that it can be treated adequately. This awareness may induce them to perform the test and therefore a COPD screening. Furthermore, this might also induce them to quit smoking. In fact, a diagnosis of airway obstruction can more easily induce smokers to stop their habit ²⁴. It would be better to address a screening strategy to all smokers rather than only to subjects that show respiratory symptoms, i.e. when the disease is at an advanced stage.

Above all, scientific societies, Health Policy, mass media and doctors should make an effort to induce smokers, aged > 40 years, to perform a spirometry. Their awareness of COPD and how to screen it, could be improved by writing messages on cigarette packaging inciting smokers to perform an annual spirometry ²⁵. The media and the internet might be used to spread such messages thus increasing the above said awareness in smokers. Furthermore, they might suggest performing a screening by sending letters as we do for other kinds of diseases.

To help smokers to be more aware about COPD, the use of a simple understandable language when dealing with them should be considered. In fact, the term COPD does not explain to them what the disease is and how severe it might become.

To help smokers to be more aware about COPD, the use of a simple understandable language when dealing with them should be considered.

This is a term used mostly by pulmonologists. Scientific societies should formulate a more articulated expression that would clearly explain how serious this disease is. For example, the use of the term “emphysema” may have a stronger impact on people because it is a well-known expression with a clear negative connotation ²⁵. In addition doctors, when dealing with smokers with COPD, should try to communicate clearly to their patients how severe it might become if they do not stop smoking. Unfortunately, a substantial proportion of general practitioners does not know their patient’s smoking status ²⁶.

Chest X-rays for smokers aged > 40-50 years

As for LC, we have been debating for about 30 years about the possibility to use Low Dose Computed Tomography (LDCT) in LC prevention without reaching any clear agreements, although everybody knows that this is an effective test to diagnose the disease precociously. Probably, one of the reasons why it has not been used on a large scale up to now is because of its high costs, excessive radiation and low accessibility. However, while waiting for a suitable test for LC screening, chest X-rays (CXR) may be regarded, for the time being, as a sufficient alternative. In fact, as it is available everywhere, because of its lower costs and because it does not require a very high competence to be interpreted, CXR is an eligible tool to effect a large-scale screening/prevention ²⁵.

Because of its lower costs and because it does not require a very high competence to be interpreted, CXR is an eligible tool to effect a large-scale screening/prevention.

If we advised all smokers aged > 50 years (with a higher LC risk) to perform an annual CXR we would have a worldwide LC screening. When an abnormality is found, we can further investigate with a lung CT that is, undoubtedly, more specific and sensitive. This approach may be an alternative to an immediate LC screening with lung CT. In fact, according to some studies, by first using an annual CXR screening, LC mortality is reduced by 18% ²⁷. In particular, according to Dominioni ²⁸, the rates of stage I LC, resectability and 5-year survival were nearly twice as high in participants to CXR screening (32% stage I; 48% resected; 30.5% 5-year survival) in comparison to nonparticipants (17% stage I; 27% resected; 13.5% 5-year survival). Other authors have also observed that lung cancer was diagnosed in 1.1% of smokers (> 30 pack years) with a low-dose CT, whereas in 0.7% with CXR ²⁹. In addition, annual CXR screening for high-risk smokers, in the general practice setting, has a high probability of being cost-effective ³⁰. On the contrary, other evidence does not support screening for lung cancer with chest radiography. In a large study, including both smokers and non-smokers, the comparing of annual CXR screening with no screening at all showed no reduction in lung cancer mortality (RR 0.99, 95% CI 0.91 to 1.07) ³¹. In addition, another meta-analysis did not find any screening effectiveness for lung cancer with chest radiography ³². In fact CXR, as already stated, has a reduced sensitivity in screening lung cancer when compared to LDCT. Sensitivity and specificity were 93.8% and 73.4% for low-dose CT and 73.5% and 91.3% for chest radiography, respectively ²⁹.

However, while waiting for LDCT to become a validated procedure for early LC screening, if such a procedure is performed annually by millions of smokers, the number of human lives that might be saved could be very high, even if CXR might also lead to some false positives ^27-29 and has less sensitivity (than LDCT). On the other hand, CXR screening is obviously better than no screening at all. CXR, like spirometry, being easily available, should be made more familiar to smokers in order to induce them to perform this test regularly. These tests and LDCT, when licensed, should become, if effectively publicized, as popular as the Papanicolau (PAP) smear test, mammography and Fecal Occult Blood Test (FOBT), which are already efficaciously used in cancer prevention in the same way as controlling blood pressure and cholesterol levels are for cardiovascular diseases ²⁵. Also CXR, like spirometry, should be performed regularly by smokers > 50 and not only when they show symptoms.

Furthermore, performing a screening may induce the risk awareness for lung cancer and consequently increase smoking cessation motivation.

Proposing LDCT for LC screening?

As already said, LDCT is more effective than CXR in screening lung cancer ^{29 32 33}. Furthermore, evidence shows that LDCT screening can reduce lung cancer and all-cause mortality ^{29 32-34} of 20% and 6.7% respectively ³³.

Evidence shows that LDCT screening can reduce lung cancer and all-cause mortality of 20% and 6.7% respectively.

Other studies have not found any screening benefit ^35-37, but the research was characterized by a low number of subjects. In addition, LDCT screening may encourage behavioral changes towards smoking. In fact, some studies observed that smokers who were participating in lung screening trials were associated with increased habit quitting or a long term smoking abstinence ^{38 39}.

Moreover LDCT has some risks including radiation exposure, overdiagnosis, cost-effectiveness and a high rate of false-positive findings that might limit lung cancer screening with it ⁴⁰. However, the United States Preventive Services Task Force, as well as other american medical societies, recommends lung cancer screening with LDCT in adults aged 55 to 80 years with a 30 pack-year smoking history and currently smoking or who have quit within the past 15 years ⁴⁰. Obviously, smoking cessation treatment must be adjunct to screening. In Europe, there are still no lung cancer screening recommendations or reimbursed screening programs.

However, the European Society of Radiology and the European Respiratory Society have both recently recommended lung cancer screening within a clinical trial or in routine clinical practice at certified multidisciplinary medical centers for smokers aged between 55 and 80 years, with a tobacco smoking history of at least 30 pack-years, and for current smokers or ex-smokers who have quit smoking within the last 15 years ⁴¹. All screened subjects must also be included in a smoking cessation program ⁴¹. Therefore, we hope that at least in some certified multidisciplinary italian medical centers, LDCT for lung cancer screening will soon be available. This could be a problem only in the case that the Italian National Health System would stop reimbursing the costs for the test. In February 2015, Medicare (U.S. government insurance) announced its decision to cover annual lung screening for patients with a significant smoking history.

Smoking cessation promotion

Quitting smoking is the most important prevention intervention for smokers. In fact, it significantly reduces the overall mortality of smokers more than LDCT screening.

Beneficial effects of stopping smoking on mortality seem to be threefold to fivefold greater than the ones obtained by early diagnosis.

Beneficial effects of stopping smoking on mortality seem to be threefold to fivefold greater than the ones obtained by early diagnosis in the National Lung Screening Trial ^{6 29 33}. Seven years of smoking abstinence reduced lung cancer mortality at a level more or less similar to LDCT screening ⁷. This reduction was greater when abstinence was combined with screening, stressing the importance of smoking cessation efforts in screening programs ⁷.

Smoking cessation is the most effective intervention to prevent the annual decline in lung function and to avoid or reduce the progression of COPD.

Furthermore, evidence for the benefits of stopping smoking was also seen in COPD ⁴².

In fact, smoking cessation is the most effective intervention to prevent the annual decline in lung function and therefore to avoid or reduce the progression of COPD ^{43 44}.

Therefore, we need to implement all possible educational and communicative strategies to increase smoking cessation ⁴⁵. Especially, we should increase smokers’ awareness of smoke induced diseases such as COPD, cardiovascular diseases and cancer. Such informations should be given during school years.

Conclusion

To sum up, smokers at risk should be educated and incited to perform a COPD/LC screening. In fact, educational strategies increasing smokers’ awareness in order to induce smokers to have an annual screening with spirometry, CXR or better LDCT, could have a great impact on public health.

Educational strategies increasing smokers’ awareness in order to induce smokers to have an annual screening with spirometry, CXR or better LDCT, could have a great impact on public health.

A regular screening might favour an early diagnosis and reduce management costs. It might also persuade smokers to quit their habit and above all save a large amount of human lives. However, nowadays the best intervention remains “stopping smoking” which reduces the risk of smoke-induced diseases. Such intervention could effectively be improved by increasing the knowledge of the negative consequences of smoking.

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