Frequently asked questions

General questions

4-IN-THE-LUNG-RUN is a population screening study into the early detection of lung cancer. Lung cancer is an important issue within public health. Over the past year, approximately 10,000 people have died from lung cancer. Approximately 1 in 5 people that die from cancer, die from lung cancer. 

We know that lung cancer-related deaths can be reduced. Of every 4 people that would die from lung cancer without screening, 1 could be saved by performing screening. However, we would still like to answer a few important questions before lung cancer screening can be implemented on a large scale in Europe.  We would like to examine the best way to detect lung cancer at an early stage. 

Because we know how quickly lung cancer can grow, we should be able to annually screen people who have a high risk of lung cancer. And this should be done over a period of 20-25 years. But this is demanding for the people themselves, as well as the healthcare system. We believe that, once the first CT scan has been carried out, it is possible to assess whether we can wait slightly longer for the next scan; for example, 2 years instead of 1 year. 

We are using this study to specifically focus on people where no indications of lung cancer are found on the first CT scan. For approximately 9 in 10 people, no indications of lung cancer a found during the first CT scan. We would like to know whether it is equally safe to invite this group of people for a CT scan every 2 years instead of every year. This will greatly reduce the number of examinations, and thus also the disadvantages experienced by the people themselves.

If you are interested in taking part in the study, we ask you to fill in the questionnaire and the informed consent. 

The study team will carefully examine the completed questionnaire. The study team will then determine whether you meet all requirements for participation. . 

You will only become a participant in the study once you have completed and returned the informed consent, and are deemed eligible. We will notify you if your are able to participate.

Take your time when deciding whether or not you want to participate. The registration process for participation will only close in a few months’ time. When the time comes, we will mention the closing date on the website.  

You do not have to do anything if you do not want to participate.

The aim of the study is to trace and treat lung cancer in people who do not yet have lung cancer but are at a high risk of getting lung cancer. Naturally, the goal is to reduce lung cancer deaths in the future. If you have had lung cancer in the past, you are not eligible to take part in this population screening study.

3 hospitals and regions in the Netherlands are taking part in this study. All men and women between 60 and 79 years who live near these hospitals will be invited to complete a questionnaire. Your details have been obtained from the Key Register of Persons (BRP). Permission to do so was obtained from the Ministry of the Interior. Only authorised study staff will be able to access your details. We will destroy your details if you do not take part in the study.

It will not cost you anything to take part in the study. We will pay for all examinations that are needed for the study. Namely, the CT scans for which you will be invited. You do not have to pay anything for them and they will also not be charged via your health insurance. You will be able to claim your travel expenses.

For approximately 8 in every 100 participants, the CT scan will show abnormalities that require further examination by a lung specialist. This will no longer be part of the 4-IN-THE-LUNG-RUN study. As soon as you consult the lung specialist, all costs will fall under your health insurance. This is also how things were arranged in other population studies in the Netherlands. Further examinations deemed necessary by the lung specialist may be (partly) charged against your deductible. Some medicines are also subject to a personal contribution. 

In the Netherlands there are currently three screening centers licensed to perform the CT examination for this study. These are: the AVL Center for Early Diagnosis in Amsterdam, Link2Care Clinics in Bilthoven and the Nij Smellinghe Hospital in Drachten. If you have been invited by letter for the study, you will automatically be invited to the nearest screening center. If you register without an invitation, you can indicate in the online questionnaire which location you prefer.

If you register without an invitation, you can currently only go to the Link2Care Clinics in Bilthoven (Utrecht) for your CT scan.

The result of the examination

There are three possible results: Negative, positive and doubtful. 

What is a negative screening result

This result means that no indications of lung cancer were found on the CT scan. This is the most commonly encountered result. Approximately 82 in every 100 people will receive a negative test result.  A negative result for the first scan means that you will be invited for a CT scan again until you have completed all CT scans. The study group to which you have been assigned will determine when your next CT scan takes place. 

What is a positive screening result

The CT scan shows abnormalities in the lung that point to lung cancer. Further examination by the lung specialist is needed to determine whether it actually involves lung cancer. The size and location of the deviation will determine which examinations are necessary. The lung specialist will discuss this with you when you are referred. 

Approximately 8 in every 100 people receive a positive result. But not all people actually have lung cancer. Of every 2 people who are referred to the lung specialist, 1 person will effectively have lung cancer. The lung specialist will mention the treatment options if lung cancer is discovered.

What is a doubtful screening result

The CT scan showed a few minor abnormalities in the lungs, which do not immediately point to lung cancer but there are still doubts. This is often inflammation or scarring. To be on the safe side, an extra CT scan will be carried out after approximately 3 months. Approximately 10 in every 100 participants undergo a repeat CT scan. This is not the same as a referral to the lung specialist. A repeat CT scan makes it possible to compare the two CT scans with each other. This makes it possible to measure the speed with which the spot has grown.

Minor spots that have not, or have barely, grown require no further treatment. This will lead to a negative result. Spots that grow quickly are more suspicious. They will result in a positive result

You will receive the result of your examination within 3 weeks. If you still have not heard anything after 3 weeks, then contact the study team via the contact form or Our employee will then examine why you have not yet received your result.

Do you have a question about 4-In-The-Lung-Run that you would rather not ask the researchers? Then you can call or email an independent doctor, Prof. dr. Agnes van der Heide.

Phone: 010-7043719



The first results will not be available for quite some time. But we will inform you as soon as they are. Naturally, you will always be informed about your personal results from the CT scan.

If you are at high risk of lung cancer, we will use a CT scanner to take images of your lungs. By taking images of your lungs, we can examine whether you have spots on your lungs that could point to lung cancer.  This will increase our chances of detecting lung cancer in an earlier stage. There are often more possibilities for treating lung cancer in an early stage. Without screening, lung cancer is normally discovered in a late stage. Very few people can be treated effectively at this point. 

By taking part in the population screening study, you will make an important contribution to knowledge about the early detection of lung cancer and the improvement of healthcare.

  • Early detection of lung cancer reduces the risk (approximately 24%) of dying from lung cancer.
  • Your prospects will improve if lung cancer is treated at an early stage.
  • Treatment is often less invasive if lung cancer is discovered early.
  • The CT scan is painless and is completed within 10 minutes. A contrast medium is not used.

  • You may start worrying or feel anxious when being examined or waiting for the result.
  • Even after further examination, it may transpire that you do not have lung cancer.
  • A CT scan uses X-rays.
  • Lung cancer may be discovered that is growing so quickly that treatment is no longer possible.
  • Lung cancer may be discovered that is growing so slowly that it will not have caused you any inconvenience during your life.

Screening for lung cancer is mainly useful for people with a high risk of developing lung cancer. Lung cancer is mainly encountered in people who have smoked for a large part of their lives. Are you between 60 and 79? For instance, have you smoked at least 1 pack a day for 25 years? Or perhaps at least 2 packs for 15 years? And if you have stopped smoking, did you do so after 2005? Then you will probably be eligible for the study. If you have doubts about whether you are eligible, you can also perform a self-test online to see if you may be eligible to take part in the study.

Then we expect you to have a lower risk of lung cancer and you may experience more disadvantages by taking part. This means screening may be less useful or completely pointless for you at this moment in time. This does not mean you cannot get lung cancer. That is why you should always consult your GP if you suffer symptoms that are associated with lung cancer.

If you would prefer to speak to a member of the study team, please feel free to contact us via the contact form or You can also phone the free help desk of I&O Research: 0800-0191. 

In a population screening, a large group of people is examined for the presence of a disease. Importantly, it can have large benefits for a small group but also smaller negative consequences for a larger group. Important advantages are: fewer deaths from lung cancer and that more treatments are less invasive. But screening also has disadvantages, such as the exposure to a low dose of X-ray radiation through the CT scans. Participation can also cause fear/uncertainty while scanning and waiting for the results. It is also possible that an abnormality is seen, but that after additional examinations it turns that it is in fact not lung cancer (false positive result). It is very important that the benefits clearly outweigh the harms: we call this the benefit-risk ratio. This is also stated in the Dutch Population Screening Act.

It is important that we know who has a (high) risk of the disease. Smoking behavior is an important part of determining lung cancer risk. Around 80-90% of lung cancers are related to smoking history. Importantly, at least half of the people with a high risk have already stopped smoking. However, the risk remains high for a long time, even after quitting smoking. Factors such as secondhand smoke (passive smoking) and air pollution/chemical substances increase the risk of lung cancer. These factors can be taken into account in the coming analyses and once there is more clarity about these various factors, they will certainly be included in the selection criteria. Until then, it is important to be alert to complaints that may indicate lung cancer if people were exposed to long-term secondhand smoke or polluted air. 

The invitation is only valid for the person to whom the letter is addressed. As a result, it is not possible to send someone else on your behalf. Before the CT scan is carried out, we will check whether the correct person is in attendance.

We believe it is important for your GP to know all about your health. We are also legally obligated to supply this information to your GP.

We only use all study data (results, your answers to the questionnaire and the requested details) for the 4-In-The-Lung-Run study. We make sure that researchers never know to whom the details belong. We do this by linking your personal data (name, address ad date of birth) to a unique code: your study number. Researchers will only see the code and will thus also not use your name in the articles or reports that they write. Your data will also not be shared with third parties, like e.g. your health insurer.

However, some employees will be able to access your name and address. This is needed to invite you to the examinations or to share the results with you. These employees comply with the General Data Protection Regulation and the Privacy Regulations of the Erasmus MC.

All people within a particular age group in several municipalities have been invited; that is why these people have also received an invitation. However, from a legal perspective, it is not possible for them to take part in scientific research under the same conditions as legally capable persons. In principle, invitees that are legally incapable are not permitted to take part in 4-In-The-Lung-Run. Legal representatives can contact the study team if they have any questions.

Informed consent

Below we have described exactly why you must provide consent and for which purpose the data will be used:

We believe it is important for your GP to be informed about your results so that s/he possesses all relevant information about your health. We are also legally obligated to supply this data to your GP. In addition, we will send the results to the lung specialist and other relevant care providers, like a quit smoking coach, so that they possess the information needed for the concerned treatment. This will only relate to the results of the screening (CT scan).

In the Netherlands, accurate records are kept about who is suffering from lunger cancer and the treatment they receive. This is done by the Netherlands Cancer Registry/PALGA. We are using 4-IN-THE-LUNG-RUN to examine whether it is safe enough to reduce screening intervals for certain groups of people with a high risk of lung cancer. Using the Dutch registration system will offer us good data for all participants. This is very important to arrive at a suitable conclusion.

We want to see if we can reduce the number of CT scan examinations in people whose first CT scan showed no indications of lung cancer. As a result, for all participants, we must know how many people get lung cancer and which stage the lung cancer is when it is discovered. We would also like to know how many people eventually die from lung cancer. Hospitals normally register who was admitted and why. By requesting this data, we will know exactly how often lung cancer is encountered and how many people were treated for lung cancer in the hospital. It is important for us to have very accurate information about this. Only then will we be able to say whether it is worthwhile reducing the number of CT scan examinations.

In some cases, we may not possess enough information when referring someone to the lung specialist. Lung cancer is confirmed in approximately half of all referred people. Lung cancer is not found in the other half. Via your GP, lung specialist or other care provider, we can discover which examinations and treatments were provided. In all cases, we will only request data that relates to this study. We are unable, and are not permitted, to request other data. If you want your study data to be sent to your treating physician, we will always ask you to first provide written consent.

The Key Register of Persons was previously known as the Municipal Basic Administration. The Key Register of Persons contains information about you, such as your name, address, date of birth, etc. This information is, for example, also used by the government when sending you letters. We have had to follow a strict procedure, where we had to ask for your permission and explain why we need the data in question. Naturally, we will only receive a limited amount of data from the Key Register of Persons. We can only access the Key Register of Persons to obtain data that is needed to check whether you are the person to whom we want to send our letter (name, date of birth and sex). We will also obtain details that are needed in order to contact you (name, address, post code and town/city). Of course, we will only receive this information for the duration of the study. Thereafter, we are not allowed to use this information.

Statistics Netherlands (CBS) registers the cause of death for every person that dies. This cause of death is registered using a code that is used internationally.  At the end of the study, we will contact Statistics Netherlands to request this cause of death code for people that we know have died.

Have you lost the informed consent?  Contact the study team via the contact form or via

You can also phone the free help desk of I&O Research: 0800-0191.