As per the World Health Organisation’s 2018 data, cancer caused 9.6 million deaths worldwide. That means almost one in six people died of cancer. Lung cancer has been ravaging India for a long time. Being the third most common cancer, it is vital to be aware of lung cancer symptoms, diagnosis and treatment procedures.

Therefore, after compiling information from several sources, we present an article on lung cancer and everything one should know about it.

Keep reading to know more!

Lung cancer is an abnormal growth of cells in the lung tissues that may spread to other parts of the body by the process of metastasis. Cancer primarily starts in the lungs and starts showing early symptoms. Upon timely detection, one can opt for proper treatment.

However, lung cancer or lung carcinoma is not curable. As this cancer starts in the lining of the bronchi and bronchioles, it hinders the exchange of gases in the lungs and often results in breathing difficulty. Further, lung cancer is common among smokers who are exposed to tobacco smoke.

Apart from this, there are several risk factors of this type of cancer. An individual can take appropriate preventive measures once they gain clarity regarding these factors.

It is also crucial to learn about the types of lung cancer as it helps to deduce the severity of the disease.

There are two major types of lung cancer, non-small cell lung cancer and small cell lung cancer. These types have several subtypes that help in determining their symptoms and suitable treatment procedures. 

Here are the details of the various types and sub-types of lung cancer:

Non-small Cell Lung Cancer (NSCLC)

Most lung cancers (around 80% to 85%) are NSCLC type. It has several subtypes like adenocarcinoma, squamous cell carcinoma and large cell carcinoma, which are grouped together because their treatment is often similar.

• Adenocarcinoma: This occurs in the mucous-secreting cells of the lungs. Women, current or former smokers, younger people are vulnerable to this form of cancer. It generally starts in the outer part of the lungs and is detected before it has spread to other tissues. Therefore, people with adenocarcinoma have a better shot at treatment.
• Squamous Cell Carcinoma: Squamous cells line the inner part of the lung airways. Cancer in these cells is termed squamous cell carcinoma. It is common in smokers and found in the central part of the lungs near the bronchus.
• Large Cell Carcinoma (Undifferentiated): This type of cancer can occur in any part of the lungs. It grows and spreads quickly, making it hard to treat.

Apart from this, there are some other rare cancers like adenosquamous carcinoma and sarcomatoid carcinoma.

Small Cell Lung Cancer (SCLC)

Also known as oat cell cancer, this is among 10%-15% of individuals. They spread and grow faster than NSCLC. 70% of the people with this type of cancer show symptoms of spreading during diagnosis. Treatment procedures for this type of cancer include chemotherapy and radiation therapy.

Other than this, there are some other types of lung tumours like lung carcinoid tumours and cancers that start in other organs like the breast, kidney, pancreas and spread to the lungs.

The symptoms of lung cancers do not differ much depending on their types. In the following section, we have discussed lung cancer symptoms based on their stages.

Some of the early symptoms of lung cancer include:

• Coughing gets worse with time and does not go away easily.
• Blood or phlegm witnessed during coughing.
• Chest pain that worsens during deep breathing, laughing, or coughing.
• Hoarse voice.
• Shortness of breath.
• Wheezing.
• Fatigue and weakness.
• Sudden weight loss and loss of appetite. 

In some cases, patients might get recurrent infections like pneumonia and bronchitis.

As cancer spreads, some more severe symptoms are observed in the following regions:

• Lymph Nodes: lumps in the neck or collarbone. 
• Bones: pain in the back, ribs or hips.
• Brain or Spine:  numbness in hands or legs, dizziness, headache, balance issues.
• Liver: Jaundice, yellowing of skin and eyes.

In case the tumour is located at the top of the lungs, it can affect facial nerves resulting in drooping of one eyelid, reduced perspiration on one side of the face, small pupil or shoulder pain. Together, these symptoms are called Horner syndrome.

Further, the tumour can press on the pulmonary veins that transport blood to the head, arms, and heart, causing swelling of the face, neck, and upper chest and arms.

Lung cancers also produce certain hormone-like substances leading to a variety of symptoms known as paraneoplastic syndrome. These symptoms are:

• Muscle weakness
• Nausea
• Vomiting
• High blood pressure
• Fluid retention
• High blood sugar
• Confusion
• Seizure 
• Coma

Now that the lung cancer signs are clear, one should be aware of its causes.

One of the primary causes of lung cancer is smoking. The minute smoke enters the lungs, it corrodes its lining and starts damaging its tissues. In some cases, the lungs can repair these damages. However, due to prolonged exposure, the lungs fail to keep up with the repairs and increases the chances of developing cancer.

According to the American Lung Association, exposure to naturally occurring radioactive substances like radon can cause lung cancer. This gas escapes through the crack of the building. Therefore, smokers inhaling this gas can are at high risk of developing lung carcinoma. 

Substances like asbestos can cause mesothelioma, a type of lung cancer. Some other hazardous materials that cause lung cancer are:

• Cadmium
• Chromium
• Arsenic
• Petroleum products
• Nickel
• Uranium

Note: Inherited genetic mutations can increase the probability of lung cancer, especially if a person belongs to a family with a smoking history or is exposed to other carcinogens (cancer-causing substances).

Now let’s delve deeper into the stages that will help in detecting the lung cancer symptoms for better treatment opportunities.

Diagnosing lung cancer in the early stages is difficult as it does not show obvious signs. However, early detection increases the chances of successful treatment. In the following section, you will find the stages of various types of lung cancer, which will aid in early diagnosis. 

Non-small cell lung cancer stages are as follows:

• 1: Detection of cancer occurs in the lungs. But it has not spread to any other region.
• 2: In this stage, one can find cancer in the lungs and the nearby lymph nodes.
• 3: Identification of cancer in the middle of the chest in lungs and lymph nodes.
• 3A: Cancer appears in the lymph nodes present at the side of the chest where the initial growth occurred.
• 3B: Occurrence of cancer in the opposite side of the chest in the lymph nodes.
• 4: It has spread to both lungs, in and around lungs and distant organs.

The small cell lung cancer has two stages: the limited stage, where the cancer is limited to one lung or nearby lymph node or one side of the chest and the extensive stage.

In the extensive stage, cancer has spread to the following regions:

• Throughout one lung.
• Lymph nodes on the opposite lung.
• The opposite lung.
• Fluid around the lungs.
• Bone marrow.
• Distant organs.

Most lung cancer patients with SCLC are diagnosed in the extensive stage.

Upon knowing the lung cancer stages, its diagnosis becomes easier.

If an individual shows any symptoms of lung cancer, a health professional will prescribe some diagnostic tests as follows:

• Imaging Tests: X-ray, MRI, CT and PET scans show a detailed image of abnormal cell mass or minute lesions.
• Sputum Cytology: The microscopic examination of phlegm during cough can also detect cancerous cells.
• Tissue Sampling or Biopsy: Biopsy determines the presence of cancerous cells. The tissue sampling is carried out by bronchoscopy, mediastinoscopy or needle. After sample collection, they are sent to pathological laboratories for analysis. If the results are positive, patients will be asked to obtain a bone scan, which helps stage cancer.

After finalising the cancer type, its stage, and other details, doctors will prescribe an appropriate course of action that will help treat the disease.

Lung cancer treatment depends on a number of factors, including the cancer type, location and stage, patient’s overall health condition, and preferences. It is also important to note that cancer treatments have side effects. Therefore, considering all these pointers and consulting with a doctor, one must choose the most appropriate course of action. Here are some treatment options available:

• Surgical removal of part or whole of lungs.
• Chemotherapy, a drug treatment that kills cancerous cells and shrinks the tumour size.
• Radiation therapy, using high energy rays to kill cancer cells.
• Radiofrequency ablation, wherein a doctor will stick a needle to the cancer region and pass an electric current through it to destroy the cells.
• Targeted therapy targets a certain region to prevent tumour growth.
• Immunotherapy helps the body fight against cancerous cells.
• Palliative therapy, pain relief, oxygen therapy and others are necessary to manage lung cancer symptoms.

As mentioned, treatment for lung cancer has side effects that might even damage the non-cancerous cells. Therefore, it is wise to prevent the disease effectively.

Although one can follow a number of ways to prevent lung cancer, there is no sure way. However, the key to a healthy life is practising a good diet and letting go of bad habits. Here are a few things one can do to prevent deadly diseases like lung cancer:

• Avoid Smoking: It is a proven fact that smoking causes cancer. Therefore, it is advisable not to start smoking and lead a healthy life. Smokers should leave smoking immediately and lower the risks of lung cancer. 
• Reduce Passive Smoking: Researches show that a non-smoker inhaling the smoke can also cause lung carcinoma. Therefore, non-smokers should avoid passive smoking at any cost and urge smokers to smoke outside.
• Radon Test for Homes: One should not keep any cracks on the floors and walls of his building as radon might escape through those cracks. Additionally, they should check their home radon levels with experts.
• Avoid Carcinogens at Workplace: Factory workers should follow precautions while working at factories as these places are exposed to carcinogens. They should wear a mask and protect themselves from inhaling poisonous fumes and reduce the risk of lung cancer. 
• Eat Healthily: Maintaining a balanced diet by including fruits and vegetables is vital to keep away ailments, including lung cancer. It is wise to use a natural source of vitamins and minerals than pills, and other medicines as these might cause other problems. 
• Daily Exercises: With a healthy diet comes physical exercises that prevent lung cancer and maintain a good physique.

Finally, one can prevent lung cancer better if he has prior knowledge of its risk factors.

From the aforementioned details on lung cancer symptoms, causes, types, treatments and prevention, it is clear that fighting against any disease becomes easier once you know everything about it.