Health Tips

Lung Cancer: Early Detection, Diagnosis, and Staging

Welcome back to the series fellow readers! This week, we are diving deeper into the early detection, diagnosis and staging of LUNG CANCER.

To learn more about the symptoms and risk factors of Lung Cancer, do check out our previous articles here:

Early detection of lung cancer

Early detection of lung cancer does not only result in a better treatment outcome, it can also detect cancer before symptoms and signs appear. ¹ Screening tests are used for the early detection of cancer. For lung cancer, the screening tests performed are low-dose CT (LDCT) scans. ²

Low-dose CT (LDCT) scan (Image from: Loma Linda University Health)

Abnormal areas in the lungs can be detected by LDCT scans, which are normally used for people who have a higher risk of getting lung cancer. ² The high-risk group of lung cancer in Malaysia includes people who are: 

• Ex-smokers or current smokers between the age of  50 and 70 years old without a history of lung cancer. ³
• Ex-smokers or current smokers with a 30-pack-year smoking history. ³

According to the American Cancer Society, the
(number)-pack-year smoking history = (number of packs of cigarettes per day)* (number of years smoked).

In this case, someone with a 30-pack-year smoking history:
May have smoked 3 packs of cigarettes per day for 10 years: [3*10= 30-pack-year smoking history]
or
May have smoked 1 pack of cigarettes per day for 30 years: [10*3= 30-pack-year smoking history] ²

• Ex-smokers or current smokers with a 20-pack-year smoking history & with 1 additional risk factor. ³

The additional risk factor may be: Radon exposure, Occupational exposure, Cancer history, Family history of lung cancer, or Chronic lung disease (Chronic Obstructive  Pulmonary Disease (COPD), Pulmonary Fibrosis, Idiopathic Pulmonary Fibrosis, or  Post Tuberculosis Fibrosis).  

People with these conditions can reduce their risk of dying from lung cancer by getting LDCT scans yearly before symptoms appear. ²

How to diagnose lung cancer?

After having screening tests performed, abnormalities in or nearby the lungs might be found that are suspected to be cancer. However, it is still not confirmed whether what’s found is cancer or not, which is why other tests should be done to diagnose lung cancer. ²

Some imaging tests performed to look for lung cancer include: 

• Chest X-ray: Chest x-ray abnormalities might indicate lung cancer, but they might also be other diseases such as fibrosis, lung infection or calcium deposition. ⁴

• Computerised tomography (CT) scan of the thorax: CT scans can provide us with a three-dimensional view of our lungs. It can also measure the size and metastasis (spread) status of the tumour, giving an indication of the cancer's stage. ⁴

• Positron Emission Tomography (PET) scans: This is done for cancer detection and to identify metastases. ⁴

Some tests performed to diagnose lung cancer: 

• Sputum examinations: The lab looks at a sample of sputum (mucus you cough up from your lungs) to check for cancer cells. ^4,5

• Pleuroscopy: When there is a large amount of fluid in the pleural cavity, which might be a result of primary or secondary/metastatic cancer, the procedure will be performed. A pleuroscope, where a camera is attached to the tube, is used in the process. Biopsies can be performed to determine what kind of lung cancer it is, in addition to removing the extra fluid for diagnostic purposes. ⁴
  
    Pleuroscopy (Image from: Dr Nick Wilsmore)

• Bronchoscopy: A flexible tube with a video camera attached, which allows the doctor to see the airways is used in this process. If something unusual is found, a biopsy will be performed to determine what kind of lung cancer it is. ⁴
  
   Bronchoscopy (Image from: Mayo Clinic)

What are the different stages of lung cancer?

According to how they appear under a microscope, there are two main types of lung cancer: Non-small cell lung cancer and Small cell lung cancer. The ways of determining the stages of these two different types are different. ^6,7

1. Non-small Cell Lung Cancer (NSCLC)

There are 5 stages of non-small cell lung cancer, ranging from zero to four. In different stages, the earlier the stage is, the lesser the cancer has metastasized (spread) to other areas. ⁷

Stages of NSCLC (Image from: BioRender)

• Stage 0: The lung cancer has not spread at this stage and is only in the top lining of the lung or bronchus. ⁷ To learn more about lung structure, read It’s November Now! Lung Cancer Awareness Month.

• Stage I: At this stage, cancer has not spread to any lymph nodes or other parts of the body. Depending on the tumour’s size, NSCLC is divided into two sub-stages, 1A and 1B. ⁷

• Stage II: At this stage, the tumours have started to spread to nearby lymph nodes, with the size of tumours growing bigger. However, it has not started to spread to distant organs in other parts of the body. Here, NSCLC is divided into 2 stages, IIA and IIB. Depending on the tumour’s size, location and whether it has spread to the lymph nodes, the 2 stages are then broken into additional sections. ⁷

• Stage III: At this stage, cancer will have progressed to lymph nodes in the mediastinum, which is the area in the chest between the lungs. Depending on the tumour’s size, location and to what extent (how far) it has metastasized, lung cancer is divided into 3 stages: stage IIIA, IIIB or IIIC. ⁷

• Stage IV: This is the most advanced form of lung cancer, in which the cancer has spread to the lining of the lung or to other parts of the body. ⁷

2. Small Cell Lung Cancer

Small cell lung cancer is less prevalent than non-small cell lung cancer. Most of the time, it occurs in heavy smokers. There are 2 stages of small cell lung cancer: Limited and Extensive. ^6,7

Stages of Small Cell Lung Cancer (Image from: GrepMed)

• Limited stage lung cancer: Lung cancer is only present in one lung at this stage, with or without metastasis to the lymph nodes in the mediastinum. ⁷

• Extensive stage lung cancer: At this stage, the lung cancer has progressed to tissues other than the originally affected lung, for instance, distant organs or the other not affected lung. ⁷

A word from DOC2US

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References:

1. NCSM (National Cancer Society Malaysia) - Cancer Screening

2. American Cancer Society - Can Lung Cancer Be Found Early?

3. Ministry of Health Malaysia - Low Dose Computed Tomography for Lung Cancer Screening

4. American Cancer Society - Tests for Lung Cancer

5. Ministry of Health Malaysia - Lung Cancer

6. Mayo Clinic - Lung Cancer - Symptoms and causes

7. American Lung Association - Lung Cancer Staging

Written by

Ms. Su Pei Wen