What are the potential complications of lung cancer screening? 

Current publications on lung cancer screening conclude that complications of screening are relatively minor and are outweighed by benefits.  Nevertheless, Medicare regulations insist that those who want to be screened must be provided with information on a long list of possible complications.  Why?

By the early 1990s, critics of lung cancer screening had proposed a long list of possible complications that might arise from lung cancer screening.  

License to smoke: The most common cause of lung cancer is cigarette smoking and it is very difficult for patients to quit smoking without counseling and assistance.  Some critics of lung cancer screening suggested that screening would provide a “license to smoke”.  That is, instead of quitting, the patient would consider CT screening as a good reason not to have to quit. Continued smoking would cause considerable harm.

Inconvenience:  Individuals have to take time off from work and travel to be screened.

Expense: CT scans cost money.  If the scan finds a nodule, further tests, and further expense can be incurred. 

Discomfort: In cancer screening, patients often must undress, have an intravenous needle placed.  Some exams like mammography can be painful. 

Anxiety:  Many persons who are considering screening are worried about the future, because they have known family members or friends who have died of lung cancer.  If a CT scan reports that a nodule has been detected, this finding can trigger an increase in anxiety.

False negative screening result:  Screening tests can miss cancers, resulting in delay that allows the undetected cancer to grow, progress and kill.  

False positive screening result: CT scans detect not just lung cancers, but also other nodules caused by benign tumors, infections like tuberculosis or many other causes. Accordingly, the finding of a nodule on a CT scan – that is not cancer = may cause anxiety.  If the finding is not managed properly – according to guidelines – further complications may theoretically ensue.

Unnecessary diagnostic testing: If a benign nodule is detected, further testing may be performed, resulting in more expense, inconvenience and exposure to radiation. 

Unnecessary surgery: In the past, many individuals who had lung nodules found on chest x-rays had surgery to diagnose or even remove non-cancer nodules.  Such surgery provides no benefit, only risk of complications or even death.  

  

Complications of unnecessary surgery: Such surgery provides no benefit, only risk of complications.  Depending upon how much lung was removed, the patient may lose exercise ability.

Death after unnecessary surgery:  Although uncommon,  in earlier years, thoracotomy for lung resection had a mortality risk of approximately 1-2% for benign nodule resection. 

Overdiagnosis of lung cancer:  Some argued that high percentages (20-80%) of lung cancers diagnosed by CT screening were overdiagnosed.  That is, these cancers would never cause any symptom or kill during normal expected life span.  

Overtreatment of overdiagnosed lung cancer: If it were true that large numbers of lung cancers diagnosed by CT screening were overdiagnosed, then it would mean that large numbers of people would undergo unnecessary operations that would not help and would harm in a substantial  number. 

Radiation carcinogenesis:  Some doctors maintain that even small doses of radiation are capable of causing cancer.  Hence CT screening might cause more cancers than it cures. 

Exploitation:  Critics expressed concern that unscrupulous doctors would seek to get-rich-quick by starting  low-quality CT screening programs.

Diversion of medical resources.  Expenditure of large amounts of money on CT screening would take money away from other more important services.  One prominent medical oncologist stated that “We cannot afford to screen for lung cancer; we need the money for treatment.”

Low cost-effectiveness;  In any case, mathematical estimates suggested that it would cost large amounts of money to save a single life from lung cancer.

Town vs. Gown:  It was predicted that, even if CT screening worked effectively in large medical centers, it would prove less effective and more risky, when performed in smaller community settings. 

Conclusion:  CT screening critics insisted that population screening (outside of research projects) should not be approved until randomized control trial (RCT) research results proved a 20% reduction in lung cancer-specific mortality and in addition showed that the benefits outweighed the risks and complications of screening.

It has taken almost twenty years to obtain RCT proof that CT screening saves lives and has low risks.  During that time period, approximately 3 million Americans died of lung cancer and very few Americans have benefited. 

The web page is designed to serve as a decision aid in shared decision making for lung cancer screening. 

What is shared decision making?  

Shared decision making is a relatively new concept in medicine that goes beyond what was previously known as “informed consent”.  The idea behind it is, idealistically, a good one; that the more a patient knows about a possible treatment, the better he can discuss it with his personal caregiver and make a decision that is best for him.  

Having said this, it must be acknowledged that there is relatively little and relatively early scientific evidence to prove that shared decision making results in more benefit than harm.

It is the author’s hypothesis, that in the specific case of lung cancer screening, shared decision making is causing far more harm than benefit.   To understand why, we need to go back to 2011.

Centers for Medicare and Medicaid Services (CMS):

At a U.S. Preventive Services Task Force (USPSTF) conference held in Maryland in 2012, Dr. Peter Bach recommended that lung cancer screening should not be implemented.  He went on to say, that if it were offered, CT screening should not be provided, unless the patient first went through shared decision making with a personal caregiver and only after reviewing information contained in a decision aid.

CMS overrode Bach’s recommendation and formally announced that Medicare and Medicaid would pay for lung cancer screening for those eligible.  

Eligibility would include those 

-between the ages of 55-77 

-who had smoked at least 30-pack years and were

– currently smoking or had quit no more than 15    years earlier. 

They also stated, however, that, before CMS would pay for CT screening, the participant must review a decision aid containing information on about a dozen very specific topics on benefits and risks of screening.  

After this, they must meet with their caregiver in a shared decision-making consultation, before making a final decision whether they wanted to be screened. 

 

This CMS decision was very unusual.

  CMS had never before placed this type of regulatory burden on any form of cancer screening (specifically including breast, colon, cervical or prostate cancers).  Furthermore, although they had insisted upon prospective randomized research to prove effectiveness of lung cancer screening, they required no such high-level evidence to show a benefit from shared decision-making. 

Are there problems with shared decision making in lung cancer screening? YES. 

1. Shared decision making has not been proved to add value. There is sparse evidence that it is helpful and that it does not result in harm.
2. Shared decision-making places an unwelcome burden upon busy primary care practitioners.  These are very hard working people, who already work long hours.
3. Furthermore, in many cases, primary caregivers are not knowledgeable in the area of lung cancer screening and feel uncomfortable answering patient questions about CT screening.  These burdens may result in reluctance on the part of primary caregivers to offer CT screening to their patients, even those at known high risk.
4. Most serious, the information on benefits and risks of lung cancer screening, contained in currently-available decision aids, is inaccurate and misleading; not by a little – by a lot.  Most of this inaccurate information comes from an article written by Drs. Gould and Bach in 2011.  This is the same Dr Bach who first proposed shared decision-making to CMS, the following year. This did not come as a surprise.  Bach had spent much of the previous decade campaigning stridently against lung cancer screening.

Has Shared decision making caused harm? Yes. 

Most forms of approved screening for cancer have “uptake” in the majority of people at risk. Specifically, far more than half of all U.S. women have had mammograms, and PAP smears.  About half of Americans over age fifty have undergone screening tests for colon cancer and more than half of all men in the U.S. have had PSA screening for prostate cancer.

Despite the CMS decision to cover CT screening for lung cancer, only a very small percentage of those at the risk level defined by CMS (estimated to be about 8,000,000 smokers and ex-smokers) have had a CT scan for screening, to date.  Various studies estimate screening participation  range between 2-6%.  

A recent decision from the United States Preventative Services Task Force (USPSFT) suggests that CT screening be extended to a wider risk group, 

-those between the ages of 50-80,

– with 20 pack-years of smoking 

(estimated to incorporate approximately 15,000,000 people). This would mean that the uptake figures above drop to no more than 1-3% of those at risk. 

 

There is no published research that has studied the question of whether low uptake is caused by the requirement for shared decision making.

Recommendations:

1. In the absence of strong evidence that shared decision-making is valuable in reducing lung cancer mortality and because it may be interfering with delivery of lung cancer screening services, the CMS requirement for decision aid-driven, shared decision making should be removed.
2. Decision aids in current use contain inaccurate information on benefits and risks of lung cancer screening, and should not be used in shared decision making. They must be replaced with decision aids providing accurate, up to date information. 
3. This web page is intended to serve as a decision aid, providing accurate and updated information on benefits and risks of lung cancer screening.  Detailed information on individual benefits and risks will be provided, in other sections of this web page. 

The web page is designed to serve as a decision aid in shared decision making for lung cancer screening. 

What is shared decision making?  

Shared decision making is a relatively new concept in medicine that goes beyond what was previously known as “informed consent”.  The idea behind it is, idealistically, a good one; that the more a patient knows about a possible treatment, the better he can discuss it with his personal caregiver and make a decision that is best for him.  

Having said this, it must be acknowledged that there is relatively little and relatively early scientific evidence to prove that shared decision making results in more benefit than harm.

It is the author’s hypothesis, that in the specific case of lung cancer screening, shared decision making is causing far more harm than benefit.   To understand why, we need to go back in time.

Centers for Medicare and Medicaid Services (CMS):

At a U.S. Preventive Services Task Force (USPSTF) conference held in Maryland in 2012, Dr. Peter Bach recommended that lung cancer screening should not be implemented.  He went on to say, that if it were offered, CT screening should not be provided, unless the patient first went through shared decision making with a personal caregiver and only after reviewing information contained in a decision aid.

CMS overrode Bach’s recommendation and formally announced that Medicare and Medicaid would pay for lung cancer screening for those eligible. 

Eligibility would include those between the ages of 55-77 who had smoked at least 30-pack years and were currently smoking or had quit no more than 15 years earlier.

They also stated, however, that, before CMS would pay for CT screening, the participant must review a decision aid that contained information on about a dozen very specific topics on benefits and risks of screening.  After this, they would meet with their caregiver in a shared decision making consultation before making a final decision whether they wanted to be screened.  

This CMS decision was somewhat unusual.  CMS had never before placed this type of regulatory burden on any form of cancer screening (specifically including breast, colon, cervical or prostate cancers).  Furthermore, although they had insisted upon prospective randomized research to prove effectiveness of lung cancer screening, they required no such high-level evidence to show benefit from shared decision making. 

Are there problems with shared decision making in lung cancer screening? YES.

1. Shared decision making has not been proved to add value. There is no substantial evidence that it is helpful or that it does not result in harm.
2. Shared decision making places an unwelcome burden upon busy primary care practitioners.  These are very hard working people, who already work long hours. Furthermore, in many cases, they are not knowledgeable in the area of lung cancer screening and feel uncomfortable answering patient questions about CT screening.  This burden may result in unwillingness on the part of primary caregivers to offer CT screening to their patients at known high risk.
3. Most serious, the information on benefits and risks of lung cancer screening contained in currently-available decision aids is inaccurate and misleading.  Most of this inaccurate information comes from an article written by Drs. Gould and Bach in 2011.  This is the same Dr Bach who first proposed shared decision making to CMS the following year. This did not come as a surprise.  Bach had spent much of the previous decade campaigning stridently against lung cancer screening.

Has Shared decision making caused harm? Yes. 

Most forms of approved screening for cancer have “uptake” in the majority of people at risk. Specifically, more than half of all women have had mammograms, and PAP smears.  About half of Americans over age fifty have undergone screening tests for colon cancer and more than half of all men in the U.S. have had PSA screening for prostate cancer.

Despite the CMS decision to cover CT screening for lung cancer, only a very small percentage of those at the risk level defined by CMS (estimated to be about 8,000,000 smokers and ex-smokers) had a CT scan for screening to date.  Various studies estimate screening participation  range between 2-6%.  

A recent decision from the United States Preventative Services Task Force (USPSFT) suggests that CT screening be extended to a wider risk group, those between the ages of 50-80, with 20 pack-years of smoking (estimated to incorporate approximately 15,000,000 people). This would mean that the uptake figures above would have to be halved. 

There is no published research that has studied the question of whether low uptake is caused by the requirement for shared decision making.

Recommendations:

1. In the absence of strong evidence that shared decision making is valuable in reducing lung cancer mortality, the CMS requirement for decision aid-driven, shared decision making should be removed.
2. Decision aids in current use contain inaccurate information on benefits and risks of lung cancer screening, and should not be used in shared decision making. They must be replaced with decision aids providing accurate, balanced information. 
3. This web page is intended to serve as a decision aid for patients and primary care physicians, nurse practitioners and physician assistants, providing accurate and updated information on benefits and risks of lung cancer screening.  This information will be provided in considerable detail, in other sections of this web page.

If you have read the prior sections, reviewed the information on your individual risk of lung cancer and would consider participating in a CT screening program, the first thing that you need to know is what your benefits might be. 

The benefits to be discussed are conditional.  They apply to an individual who agrees to 

-participate in a lung cancer screening program that meets quality standards and uses a diagnostic algorithm (like IELCAP) or a clinical practice guideline ( like NCCN),

-agrees to have a low-dose, non=contrast, spiral CT scan at yearly intervals for ten years

-follows program recommendations for further testing or biopsy and treatment.

It is probable that a person who stops being screened or does not follow recommendations, based on CT findings, will experience lower benefit and / or higher risk. 

A person who is fortunate and does not get lung cancer will receive no direct benefit from screening.  He or she might derive indirect benefit.  (This will be discussed in a future post.)

A person who is unfortunate and does get lung cancer over the next ten years will have direct benefits.

– The Lung cancer will typically be detected at an earlier point in time, before the cancer would otherwise have been diagnosed at the first onset of symptoms.  The is called a “lead=time effect”. 

The large majority of lung cancers found in patients who have no symptoms but are at increased risk are found at a smaller size than those diagnosed after symptom onset. Often they are 1 centimeter in diameter (the size of a marble), or smaller (compared to a 3 centimeter (golf ball size or often much larger ) cancer in unscreened individuals. 

The large majority of lung cancers found in CT screening are in early stage. More than 80% of CT screen-detected lung cancers are diagnosed in stage 1.  In stage 1 lung cancers that are very small, e.g. one centimeter, approximately 90% are in stage 1.

When a lung cancer is found at a small size and early stage, the cancer, in most cases, has not yet spread (metastasized) to lymph nodes or distant organs.

Treatment is, accordingly, more simple and easily-tolerated. Increasingly, surgeons remove small lung cancers using “minimally invasive” techniques, including video assisted thoracic surgery (VATS) and robotic surgical methods.  Minimally invasive surgery results in shorter hospitalization, low rates of complication and death, and faster recovery. 

In many instances, smaller amounts of lung tissue (limited resection) rather than removal of an entire lobe of the lung (lobectomy) can be performed, without compromising the chance of cure. 

Chemotherapy is seldom needed.

Of greatest importance, the chance of cure in patients with lung cancer detected by CT screening exceeds 80%, approximately five times higher than in unscreened patients. 

Even though the efficacy of CT screening in preventing lung cancer deaths was definitively established by a randomized control trial in 2011, very few of those at known high risk have been screened over the last nine years.  Recent estimates vary between 2 and 6%.

As described in an earlier page, studies reported in 1986 (chest x-ray) and 1999 (chest CT scan) showed substantially improved survival in screened individuals.

In 2ooo, there was a debate as to what should be done following the findings of the ELCAP study showing that more than 80% of people with lung cancers diagnosed by CT screening were diagnosed in stage 1, when cure rates are generally high. .

The National Cancer Institute (NCI) insisted that a randomized control trial (RCT)  called the National Lung Screen Trial (NLST) was needed to prove that lung cancer screening was effective in reducing lung cancer-specific mortality by 20%.  They maintained that a RCT was necessary to rule out the fact that a series of “biases “would make screening look more effective and safer than it really was.  The study would also determine whether there were risks associated with screening that would outweigh benefits.

Most important, NCI maintained that many of the lung cancers diagnosed by chest x-ray and CT scans were “overdiagnosed”. An overdiagnosed cancer is one that will not cause symptoms or kill during normal anticipated survival. A RCT with 25,000 research subjects in each of two arms was absolutely necessary to rule out  such overdiagnosis and prove that lung cancer deaths were reduced by more than 20%.

This idea was outlandish to an experienced surgeon like myself, who had never seen a patient with lung cancer survive untreated for more than five years.     I and many others were strongly opposed to delaying CT screening for an estimated ten years just to rule out what I have described as a “preposterous hypothesis”.

The International Early Lung Cancer Action Program (IELCAP) investigators (I was a participant) argued that, given the disparity in stage 1 diagnosis between no screening (15%) and CT screening (80%) was so great, an informed individual would not agree to be randomized into a control arm. Furthermore there was a risk that people randomized to the control arm would “cross-over” by obtaining a CT scan outside the study.

NLST took ten years to prove that CT screening did indeed reduce lung cancer deaths by more than 20% and almost twenty years to prove that overdiagnosis occurred in less than 1%.

Why then has CT screening been provided to so few individuals at risk – after 2011- when NCI advised that CT screening does reduce lung cancer deaths?

I believe that there are a number of reasons.

1. Flaws in NLST research design

2. Misinterpretation of NLST results

3. Stubbornness on the part of cancer screening critics and unwillingness to admit they had been wrong.

4. Cumbersome and slow-moving government regulatory processes.

5. Centers for Medicare and Medicaid Services (CMS) requirement for “shared decision making”,

6. combined with false and misleading information in mandatory “decision aids”.

7. Misguided financial analysis of cost-effectiveness.

8. Research results tainted by tobacco industry potential conflicts of interest.

9. COVID pandemic.

These issues will be discussed in further depth in future pages.

I have had my first lung cancer screening CT scan. What next?

What is “screening” in medicine?

Screening is based upon the simple idea that results of treatment of a disease are better – i.e. lower chance of death, faster recovery, fewer complications, less disability, less expense – when a disease has been diagnosed at an early stage, before it has caused permanent damage.

There are many ways to screen.

COVID screening is a recent example of how this process works.  COVID screening is not one single test, but rather represents a process (sometimes called an algorithm)  relying on multiple steps.

The first step is to ask questions.  A person is asked about risk factors, for example, have they recently traveled to another country? Have they been in contact with a person infected with COVID?

The next step is to screen for fever with a thermometer.

If the patient has a fever, or has had contact with a sick patient, then the risk of COVID is higher and the next step in the process is to test for COVID virus by nasopharyngeal swab.

If the COVID infection diagnosis can be made at this stage, before pneumonia and sepsis force hospitalization, treatment can be begun with antiviral drugs and or convalescent serum.  Both of these treatments have been shown to speed recovery and perhaps lower chance of hospitalization, complications and death. 

If these treatments are given only after the patient has become so sick that hospitalization in an ICU is required or ventilator support is needed, then medical treatments have less effectiveness and the chance of death or major complications is much higher. 

Everyone is familiar with many other forms of medical screening.  

When the doctor feels your pulse they are screening for cardiac arrhythmia.  

A blood pressure measurement is a screen for hypertension. 

A weight measurement screens for obesity. 

You are asked to read an eye chart to screen for vision loss.

A tonometer placed on your eyeball screens for glaucoma.

There are literally hundreds of other screens that a patient goes through in the course of medical care. There is nothing exotic or intrusive about screening in medicine.

Screening can also take place in laboratory testing.

A urine specimen can be used to screen for diabetes, kidney disease, pregnancy and other conditions.

“Routine” blood tests screen for anemia, diabetes, hyper cholesterolemia, hepatitis, kidney disease, AIDS and other diseases.  

Screening can also be carried out using x-rays and other imaging tests.  Chest x-rays were used extensively for tuberculosis in past years, when that disease was more common in the U.S. .  Pregnant women undergo ultrasound examinations to ensure that the fetus is healthy. 

The reason thatI give so many examples of screening is because, in recent years, some doctors have attacked screening, pushing forward the idea that there are major harms to screening, particularly in the case of cancer screening.

The potential risks of medical screening will be discussed further in future blogs. 

 

F.W. Grannis Jr. M.D.

July 8, 2020

To the best of my knowledge, five methods  have been used to try to detect lung cancers at a small size, before they have spread (metastasized) to lymph nodes or other body organs.’

1. Chest roentgenogram (chest x-ray)

2. Computerized tomography (CT scan)

3. Cytology- looking at cells in secretions under the microscope

4. DNA testing to look for characteristic mutations.

5. Electronic “nose” a method to measure chemicals in expired air.

Methods 3-5 are works in progress, that are not currently approved in clinical practice guidelines.  Medical history is full of exampleso how a technology improves over time.  Perhaps one of more of these methods will have proven utility in the near future, but they will not be discussed further here.

Chest s-ray was the first method of screening that showed favorable results. Early studies in London, Philadelphia and Czechoslovakia showed no benefit, but 3 prospective studies at Memorial Hospital in New York City, Johns Hopkins in Baltimore and the Mayo Clinic in Rochester Minnesota all showed striking improvement in survival in male smokers  screened with chest x-ray compared to unscreened lung cancers in national databases.  But although survival was improved, there was no measurable reduction in mortality. As a result the National Cancer Institute (NCI) concluded that chest roentgenographic screening was ineffective and potentially harmful.

On a personal note, I personally cared for patients during and after operations for screen detected lung cancers as a surgeon in training at Mayo in the early 1970s  I knew then that the lives of some patients were saved by chest x-ray screening. I believe that many lives could have been saved, if we implemented chest X-ray screening in the 1980s, but in any case CT scan is a far superior method.

CT Scan:  I saw the first CT scan machine  in the U.S. in a basement lab at Mayo, – during the early 1970s.  No one thought of using it for screening.  This was first done in Japan during the early 1990s.  Japanese radiologists first showed that CT scans could detect lung cancers as small as 2 or 3 mm in  diameter i.e. the size of a BB-gun pellet.  They also showed that this could be done with very. low doses of radiation.

These concepts were introduced in the United States by two radiologists at Cornell University in New York City, Claudia Henschke MD and David Yankelevich MD. They studied CT scans for lung cancer screening, compared to chest x-rays in 1000 research participants in the Lung Cancer Action Program (ELCAP) trial.

How does a CT scan work? I can’t describe the physics behind the method, but from the patients perspective, you do not have to disrobe, there is no IV or injection and all that is required is to lie down on a table for a few seconds.  The machine is open and so claustrophobia should not be a concern.

The ELCAP study, published in 1999 showed that CT was three times as sensitive as chest-x-rays in detecting small lung nodules.

The most important finding of the study was that more than 80% of lung cancers were detected in stage 1.  To put that in perspective, in 1999 only about 15% of lung cancers in the U.S. were diagnosed in stage 1.  Since it had already been shown convincingly that the large majority of patients in stage 1 are cured (i.e. survive more than 5-years after surgical resection) it could reasonably be assumed that CT screening could save many of the 160,000 who die each year of lung cancer in our country.

To try to prove this point, the ELCAP study was extended first to a number of hospitals in the New York City area (NY-ELCAP) and subsequently internationally to more than 70 centers around the world (I-ELCAP).

When the IELCAP study results were published in the New England Journal of Medicine in 2006, they showed that more than 80% of patients with lung cancers diagnosed by CT screening experienced 10-year actuarial survival.

Lung cancer is the most common cause of cancer death in the U.S.- by a large margin..

Your personal risk of getting lung cancer depends upon a number of risk “factors”.

Sex In the past it was primarily a disease of men, but this is no longer true.  Lung cancer now kills more women than any other cancer; more than breast, ovarian and colon cancer – combined.

Age:   Lung cancer is very uncommon (less than 1%) under age 40, but increases steadily with advancing age.

Radiation:  Historically, lung cancer was a very rare form of cancer.  It was first described among radium miners in Central Europe.  It is now known that radiation damage to chromosomes increases risk of lung cancer. This  includes atomic bomb survivors, radiation workers and household exposure to radon. Radiation risks are much smaller than risk from exposure to cancer- causing substances (carcinogens) found in tobacco smoke.

Cigarette smoking: Cigarette smoking was first recognized as a cause of lung cancer in the 1930s.  A formerly rare disease assumed epidemic proportions thereafter.  Risk of lung cancer is related to the age of starting to smoke and the number of years of smoking as well as the amount of smoking i.e. number of packs smoked per day.  This is sometimes summarized as “pack-years”.  If you smoked one pack/day for 30 years it would equal 30 pack-years exposure.

Smoking cessation:  It is important for your health that you quit smoking.  Quitting stops DNA damage from inhaled carcinogens immediately and your risk of getting lung cancer will decrease compared to a person who keeps smoking.  It is crucial to understand though that an ex-smoker continues at increased risk of lung cancer.  Some maintain that risk becomes low 15 years after quitting, but this is not true.  In Los Angeles, most ex-smokers operated on for lung cancer had  quit more than 15 years earlier.

Emphysema and Chronic Obstructive Lung Disease (COPD):: Cigarette smoking also causes other disease, including chronic lung damage.  People with emphysema have a substantially higher risk of lung cancer than smokers without emphysema.

Family History of lung cancer:  is a known risk factor for lung cancer.  This may be explained by the fact that children of smoking parents have a higher incidence of smoking.

Chemical carcinogens: Industrial workers exposed to asbestos have an increased risk of lung cancer as well as another cancer called mesothelioma.  Workers exposed to arsenic, chromates and other industrial chemicals have increased risk of lung cancer.

Pneumonia Patients who have had an infection in the lung have a slightly increased risk of lung cancer.

Lung Fibrosis:  Lung cancer is more common in people with a group of diseases classified as pulmonary fibrosis.

Prior tobacco-caused cancer:  Individuals with a prior cancer of the lung have the highest risk of a second lung cancer.  This risk is at least 20% I.e. 1 in 5 will have a second primary lung cancer during the next ten years. Risk is also very high among smokers who have had a prior cancer of the mouth, throat, larynx, esophagus and bladder.

Risk models: are used to try to estimate the risk of an individual.  There are at least 10 such models in current use and some are available on the internet.  In my opinion, the best is on a website at the University of Michigan.  The problem is that none of the models looks at all risk factors and thus all potentially provide underestimates of risk.

The National Comprehensive Cancer Network (NCCN) recommends  that individuals over the age of 50 who have smoked 20 pack-years or more are at increased risk of lung cancer and should consider screening.  They set no upper age limit for those at high risk

There are two important remaining considerations.

Medicare/Medicaid eligibility: Currently Medicaid will pay for screening only for those age 55-77 who have smoked 30 pack-years or more and who quit less than 15 years earlier.  Others who wish to be screened will have to pay out of pocket.  The cost of a low-dose, non-contrast CT scan varies considerably between $100-500 in different centers.

Never-smokers and light-smokers are currently ineligible for screening. This is despite the fact that such individuals still have a substantial risk of lung cancer.  Lung cancer in non-smokers is currently the sixth most lethal cancer in the U.S.. Lung cancer risk is substantially higher in persons with exposure to involuntary smoking so-called “second hand smoke”.

How high is the risk?

The National Lung Screen Trial (NLST study) detected lung cancer in 2.1 % of participants at six years, 1 in 50, but reappraisal at ten years showed a 6.7% incidence. That is 1 in 15.  But this number is also too low.

A study at the University of Toronto in a high-risk group showed that CT detected lung cancer in 20% over a ten year period.

At City of Hope and New York’s Memorial Hospital studies have shown that lung cancer survivors have a 20% risk of a second lung over a decade.  That is 1 in 5.

The bottom line is that if you are a middle-aged or senior adult who is a smoker or ex-smoker, you are at substantial (10-15%) risk of lung cancer, 1 in 7 to 1 in 10, particularly if you have other risk factors as described above.

Why be screened?  As discussed earlier, if you get lung cancer and it is diagnosed only after you present to your doctor’s office with symptoms, the chances are that the cancer will be advanced and chance of cure will be small.

Does screening lower the risk of dying from lung cancer?   Yes.

This will be discussed in future blogs.