Lung cancer screening 
Dr. Saran Jiramongkol
At present, lung cancer is one of the most commonly found cancers and has the highest mortality rate among all cancers. The earlier lung cancer is treated, the greater the chance of achieving a complete cure. Therefore, wouldn’t it be better if we could detect it before it is too late? And which people are considered a high-risk group? Is having an annual health check with a chest X-ray sufficient? These are questions that most people still ask themselves. This article aims to encourage everyone to look back at themselves and take better care of their health—especially since it cannot be denied that Thailand is currently facing a severe problem with fine particulate matter, Particulate Matter 2.5 (PM2.5), ranking among the worst in the world. It is well known that such dust particles are a factor that can cause respiratory abnormalities, including cancer as well.
Screening
Effective treatment of lung cancer must begin with early detection. It has been found that detecting lung cancer at an early stage results in a recurrence rate of only about 20–26%, compared with patients treated at stage 3, who have a recurrence rate as high as 52–70%. (2) Early-stage lung cancer often has no clearly noticeable symptoms, causing patients to be unaware of any abnormality until they undergo screening. Unfortunately, nowadays patients often see a doctor only after abnormal symptoms have begun, such as chronic cough, easy fatigue/shortness of breath or inability to breathe fully, coughing up blood-tinged sputum, bone pain or chest pain, hoarseness, and/or unexplained weight loss. These symptoms usually appear only after the disease has progressed for some time.
Is an annual routine chest X-ray screening sufficient?
A standard chest X-ray is typically a two-dimensional image, like viewing a person’s picture on paper. The depth of the image cannot be clearly determined. Overlapping pulmonary blood vessels—especially shadows from internal organs such as the heart, the aorta, and bones—can obscure abnormal shadows in the lungs and may lead to misinterpretation. Abnormal shadows on a chest X-ray are often seen only when a mass is large and located in an obvious position. Although AI technology is now used to help analyze chest X-rays, current AI still has a high rate of interpretation errors. Research has found that annual follow-up with standard chest X-rays does not reduce lung cancer mortality. This may be interpreted to mean that chest X-rays are not very effective at detecting early-stage lung cancer, which may delay patients’ access to treatment.
If a standard chest X-ray does not show things clearly, what should be used instead?
Chest computed tomography (CT Chest) has far greater advantages than a standard chest X-ray. Because it provides three-dimensional images, it can clearly show the characteristics of a mass as well as its location, distinguish shadows from adjacent organs, and be used effectively for treatment planning. It may also reveal other abnormalities that are not clearly visible on standard X-rays, enabling faster diagnosis. It can detect abnormalities even when they are as small as 2–3 millimeters. However, CT is much more expensive than a standard chest X-ray, and the radiation dose is higher as well.
To make screening as effective as possible and reduce the disadvantages of CT—namely the higher radiation dose and the use of contrast agents that can affect the kidneys—low-dose lung CT techniques that use less radiation and do not require contrast injection (Low-dose CT: LDCT) have been developed. This addresses the drawbacks above while retaining the benefit of three-dimensional imaging, at the cost of a slight reduction in image resolution, but abnormalities can still be seen. It can be performed more frequently and used for long-term follow-up. CT using this technique is therefore widely accepted worldwide as a screening test for lung cancer.
So when should you get screened with Low-dose CT?
Getting screened with LDCT does not have only advantages. LDCT is also more expensive than a standard chest X-ray by about one. In addition, finding an abnormal spot can affect the examinee’s mental state, even if that spot may not be serious. Therefore, to get the most benefit from LDCT, it is recommended for patients who are at high risk of lung cancer.
It is well known that smoking is a major factor causing lung cancer. It has been found that smoking increases the risk of cancer up to 20 times compared with non-smokers. But how much smoking is considered high risk? Try calculating it by taking the average number of packs smoked per day and multiplying by the number of years smoked to get the number of pack-years. If youare 50 years and calculate the number of cigarette packs smoked since 20 pack-year and above should receive screening with LDCT
Secondhand smoke is exposure to or being in an environment where people are smoking, causing you to inhale cigarette smoke without smoking directly. Although there are reports of an association with lung cancer, it is still difficult to calculate the amount the body receives, so other risks may also need to be considered.
Other risk factors to consider
Is lung cancer difficult to treat once you have it, with a high risk of death?
We often hear that treating lung cancer requires very strong chemotherapy, that surgery does not work well, that the surgical risk is high, and that it never really gets cured. In fact, for early-stage lung cancer, treatment with surgery alone can be sufficient. In addition, today’s lung surgery techniques have advanced greatly, making it possible to perform minimally invasive (thoracoscopic) surgery with smaller incisions, which is not as frightening as in the past. Detecting abnormalities at an early stage is therefore beneficial for treatment: surgery is easier, surgical risk is lower, the chance of cure is higher, and complications from chemotherapy can be reduced. So wouldn’t it be better if we could diagnose abnormalities early—before symptoms appear or before the disease reaches a stage that is difficult to treat?
Reference
Screening
Effective treatment of lung cancer must begin with early detection. It has been found that detecting lung cancer at an early stage results in a recurrence rate of only about 20–26%, compared with patients treated at stage 3, who have a recurrence rate as high as 52–70%. (2) Early-stage lung cancer often has no clearly noticeable symptoms, causing patients to be unaware of any abnormality until they undergo screening. Unfortunately, nowadays patients often see a doctor only after abnormal symptoms have begun, such as chronic cough, easy fatigue/shortness of breath or inability to breathe fully, coughing up blood-tinged sputum, bone pain or chest pain, hoarseness, and/or unexplained weight loss. These symptoms usually appear only after the disease has progressed for some time.
Is an annual routine chest X-ray screening sufficient?
A standard chest X-ray is typically a two-dimensional image, like viewing a person’s picture on paper. The depth of the image cannot be clearly determined. Overlapping pulmonary blood vessels—especially shadows from internal organs such as the heart, the aorta, and bones—can obscure abnormal shadows in the lungs and may lead to misinterpretation. Abnormal shadows on a chest X-ray are often seen only when a mass is large and located in an obvious position. Although AI technology is now used to help analyze chest X-rays, current AI still has a high rate of interpretation errors. Research has found that annual follow-up with standard chest X-rays does not reduce lung cancer mortality. This may be interpreted to mean that chest X-rays are not very effective at detecting early-stage lung cancer, which may delay patients’ access to treatment.
If a standard chest X-ray does not show things clearly, what should be used instead?
Chest computed tomography (CT Chest) has far greater advantages than a standard chest X-ray. Because it provides three-dimensional images, it can clearly show the characteristics of a mass as well as its location, distinguish shadows from adjacent organs, and be used effectively for treatment planning. It may also reveal other abnormalities that are not clearly visible on standard X-rays, enabling faster diagnosis. It can detect abnormalities even when they are as small as 2–3 millimeters. However, CT is much more expensive than a standard chest X-ray, and the radiation dose is higher as well.
To make screening as effective as possible and reduce the disadvantages of CT—namely the higher radiation dose and the use of contrast agents that can affect the kidneys—low-dose lung CT techniques that use less radiation and do not require contrast injection (Low-dose CT: LDCT) have been developed. This addresses the drawbacks above while retaining the benefit of three-dimensional imaging, at the cost of a slight reduction in image resolution, but abnormalities can still be seen. It can be performed more frequently and used for long-term follow-up. CT using this technique is therefore widely accepted worldwide as a screening test for lung cancer.
So when should you get screened with Low-dose CT?
Getting screened with LDCT does not have only advantages. LDCT is also more expensive than a standard chest X-ray by about one. In addition, finding an abnormal spot can affect the examinee’s mental state, even if that spot may not be serious. Therefore, to get the most benefit from LDCT, it is recommended for patients who are at high risk of lung cancer.
It is well known that smoking is a major factor causing lung cancer. It has been found that smoking increases the risk of cancer up to 20 times compared with non-smokers. But how much smoking is considered high risk? Try calculating it by taking the average number of packs smoked per day and multiplying by the number of years smoked to get the number of pack-years. If youare 50 years and calculate the number of cigarette packs smoked since 20 pack-year and above should receive screening with LDCT
Secondhand smoke is exposure to or being in an environment where people are smoking, causing you to inhale cigarette smoke without smoking directly. Although there are reports of an association with lung cancer, it is still difficult to calculate the amount the body receives, so other risks may also need to be considered.
Other risk factors to consider
- A family history of lung cancer, especially in first-degree relatives (parents, siblings, children), particularly if multiple family members have had cancer or if cancer was diagnosed at a young age.
- A history of having had cancer in another organ previously.
- A history of lung disease, such as emphysema and pulmonary fibrosis.
- Work that involves exposure to carcinogens such as arsenic (Arsenic), asbestos (Asbestos), beryllium (Beryllium), cadmium (Cadmium), chromium (Chromium), coal smoke (Coal smoke), diesel fumes (diesel fumes), nickel (Nickel), silica (silica), soot (soot), and uranium (uranium).
- People who live near radon (a gas produced from uranium-238 and radium-226).
Is lung cancer difficult to treat once you have it, with a high risk of death?
We often hear that treating lung cancer requires very strong chemotherapy, that surgery does not work well, that the surgical risk is high, and that it never really gets cured. In fact, for early-stage lung cancer, treatment with surgery alone can be sufficient. In addition, today’s lung surgery techniques have advanced greatly, making it possible to perform minimally invasive (thoracoscopic) surgery with smaller incisions, which is not as frightening as in the past. Detecting abnormalities at an early stage is therefore beneficial for treatment: surgery is easier, surgical risk is lower, the chance of cure is higher, and complications from chemotherapy can be reduced. So wouldn’t it be better if we could diagnose abnormalities early—before symptoms appear or before the disease reaches a stage that is difficult to treat?
Reference
- 2024 NCCN Guidelines for Lung cancer screening
- Kidane B, Bott M, Spicer J, et al. The American Association for Thoracic Surgery (AATS) 2023 Expert Consensus Document: Staging and multidisciplinary management of patients with early-stage non-small cell lung cancer. J Thorac Cardiovasc Surg. 2023
- National Lung Screening Trial Research Team; Aberle DR, Adams AM, Berg CD, Black WC, Clapp JD, Fagerstrom RM, Gareen IF, Gatsonis C, Marcus PM, Sicks JD. Reduced lung cancer mortality with low-dose computed tomographic screening. New England Journal of Medicine. 2011 Aug 4;365(5)
- Oken MM, Hocking WG, Kvale PA, et al. Screening by chest radiograph and lung cancer mortality: The Prostate, Lung, Colorectal, and Ovarian (PLCO) randomized trial.JAMA.2011;306(17):1865–1873
- Hamra GB, Guha N, Cohen A, Laden F, Raaschou-Nielsen O, Samet JM, Vineis P, Forastiere F, Saldiva P, Yorifuji T, Loomis D. 2014. Outdoor particulate matter exposure and lung cancer: a systematic review and meta-analysis. Environmental Health Perspectives 122:906–911
05 April 2024
Dr. Saran Jiramongkol
Specialty: Cardiothoracic Surgery
Related packages
View all
Lung cancer screening program with CT scan
Long-term heavy smoking, chronic cough, PM2.5 dust increase the risk of lung cancer
