Lung Cancer
Its types, causes, symptoms, diagnosis and treatment

What is lung cancer?

Lung cancer is an uncontrolled growth of abnormal cells in one or both lungs. It is one among the most common cancers in the world and usually noticed more in smokers. Lungs are two spongy organs located in the chest and are a part of the respiratory system. The lungs act as a filter for gases within the body and help in breathing in oxygen and breathing out carbon dioxide.

What is Lung cancer

What are the types of lung cancer?

Lung cancers can be classified as:

• Non-small cell lung cancer – This is the most common type of lung cancer. It can either be squamous cell carcinoma, adenocarcinoma or large cell carcinoma.

• Small-cell lung cancer – This is not a very common type but can spread rapidly.

• Lung carcinoid tumor – This is a rare type of lung cancer which affects the neuroendocrine cells.

What are the symptoms of lung cancer?

Lung cancer may not be evident in the early stages. However, in advanced stages, some of the following signs and symptoms can be present:

• Change in voice
• Tiredness and weakness 
• Frequent chest infections
• A new cough that is lasting and does not subside with routine medications
• Spitting blood while coughing
• Persistence of an old cough with a change in sound, more painful or secreting thick mucus
• Pain in bones
• Shortness of breath
• Unintended weight loss

What are the causes of lung cancer?

Smoking is considered to be one of the major contributors to lung cancer. The risk of lung cancer is higher in people who smoke (active smoker) or those who are exposed to smoke (passive smoker). However, sometimes it may be seen even in people who do not smoke. Some other factors that can increase the chances of developing lung cancer include:

• Family history: Risk increases with the presence of disease in the same family
• Toxins: Long-standing exposure to cancer-causing gases and agents like radon, asbestos, etc
• Compromised immune system: For example, people with HIV, patients on long-term steroids etc.

Causes of Lung Cancer

What are the complications of lung cancer?

Few commonly seen complications of lung cancer are:

• Breathing difficulties
• Fluid accumulation in the chest (known as pleural effusion)
• Metastasis: Spreading of cancer to nearby organs such as brain and bones
• Mouth sores, the decay of the teeth or dry mouth
• Pain in the bones due to spread of the disease in other organs and bones
• Recurrent diarrhea or constipation

What are the stages of lung cancer?

Like other cancers, lung cancer progresses through 4 stages. Sooner the diagnosis, better is the treatment approach and faster is the recovery.

Based on the tumor location, involvement in the lymph nodes and spreading, TNM (tumor, node, metastasis) staging of the tumor is performed. By staging the lung cancer, the doctor gets a better idea as to –

• What is the size and location of cancer?
• Is the tumor spreading (also called as tumor metastases), if so, spread to lymph nodes?
• What is the prognosis for the patient – chances of complete recovery and survival?

Stages of non-small cell lung cancer:

Non-small cell lung cancer is the most common types of lung cancer, accounting for 85% of total lung cancers.

Stage 0 – Cancer at this stage is still at the origin of DNA error. They are just an outgrowth that is not cancerous yet. Usually, found in the top layers of the cell lining of the airways. The tumor has not spread to lymph nodes or distant organs.

Stage 1 – Here, cancer has invaded into the deeper layers. However, the cancer is still benign. The size of the tumors may vary from 1 cm to 4 cm that may clog airways partially, invade visceral pleura, or bronchus. Yet, they have not spread to lymph nodes or distant tissues. Doctors suggest removal of the tumor and nearby lymph nodes.

Stage 2 – Stage 2 cancer has grown tissues of visceral pleura, main bronchus and its branches, chest wall, parietal pleura, phrenic nerve and membranes surrounding the heart. The stage 2 tumors vary in size but do not exceed 7 cm across. However, cancer has not touched the lymph nodes yet. The treatment usually involves surgery and adjuvant chemotherapy (treatment after surgery aimed at trying to destroy any remaining cancer cells with or without radiation therapy).

Stage 3 – Stage 3A cancer marks the spread of cancer into the lymph nodes, the gateway to move into different parts of the body. Through stage 3B and 3C, cancer progressively spreads through more number of lymph nodes and invades the nearby organs but not far away organs. Treatment options are similar to that of stage 2.

Stage 4 – At this stage, cancerous tissues can be of any size, may or may not have spread to lymph nodes. Cancer may have spread to the other lung, and fluid around lungs, or heart, tumor outside the chest or distant part of the body – such as liver, lungs, bones, or brain. The last stage 4B marks the spread of cancer into more than one part of the body.

Staging of small cell lung cancer:

Limited stage: Small cell lung cancer is now limited to one of the lungs and nearby lymph nodes.

Extensive stage: Small cell lung cancer has spread to lymph nodes and distant organs.

What is the survival rate for lung cancer?

The five-year survival rate for lung cancer is 55% when cancer is localized within the lungs. However, early detection of localized lung cancer is only 16%. The five-year survival rate for lung cancer is 17.7%. With timely care and treatment, almost half of the people diagnosed with lung cancer survivor. Patients with metastasized lung cancer have a negligible chance of survival with a poor 5-year survival rate of 4%.

How is lung cancer diagnosed?

Lung cancer is diagnosed on the basis of:

• Medical history
• Physical examination
• Tests as required
  • – Blood and sputum test
  • – Lung biopsy
  • – Chest X-ray
  • – Computerised tomography (CT) scan
  • – Magnetic Resonance Imaging (MRI)
  • – Positron Emission Tomography (PET) scan

The patient may be referred to an Oncologist or Onco-surgeon for an opinion if required.

Diagnosis of Lung Cancer

How is lung cancer treated?

The treatment options for lung cancer are based on the type and stage of lung cancer and other factors like overall health, age, and sensitivity to certain medications. The treatments for lung cancer include a combination of:

• Surgery:
  • – Robotic lobectomy: Robotic lobectomy is a minimally invasive procedure performed by the doctors using robotic tools to remove the affected lobe of the lung.
  • – Pneumonectomy: Removal of the entire lung
  • – Segmental resection: Removal of a large portion of the lung but less than the lobe
  • – Wedge resection: Removal of a small portion of the lung including the cancerous part and some adjacent healthy tissue
• Radiation therapy: High-powered radiation beams is normally delivered by a linear accelerator totarget and kill cancer cells.
• Chemotherapy: Prescribed anticancer medicines to destroy cancer cells
• Radiosurgery: Also known as stereotactic radiotherapy, high-intensity radiation is used to destroy cancer cells
• Targeted-drug therapy: Targeted delivery of radioimmunological pharmaceuticals that act on cancer cells and selectively destroy them 
• Biological therapy: Makes use of anticancer vaccines which selectively act against cancer cells
• Palliative care: Focuses on improving the quality of life of cancer patients who may not be amenable to treatment

How can lung cancer be prevented?

The risk of having a lung cancer can be reduced by lifestyle modifications like:

• Taking a healthy, nutritious diet
• Avoiding exposure to smoke or other carcinogenic gases
• Avoiding cigarettes and other tobacco-related products
• Doing regular exercise

To know more about lung cancer and its treatment, you may request a callback and our lung cancer specialist will call you and answer all your queries.

Related blogs you may like to read:

• Lung cancer causes more deaths than colon, prostate, ovarian and breast cancers put together
• What is the rehabilitation for cancer patients after chemotherapy?

References

• Mayo Clinic. Lung Cancer. Available at:https://www.mayoclinic.org/diseases-conditions/lung-cancer/symptoms-causes/syc-20374620.  Accessed on 19 March, 2018
• National health services. Lung Cancer. Available at: https://www.nhs.uk/conditions/lung-cancer/treatment/. Accessed on 19 March, 2018
• Cancer Research UK. Lung cancer. Available at: https://www.nhs.uk/conditions/lung-cancer/treatment/. Accessed on 19 March, 2018
• Lung cancer.org. Lung cancer 101. Available at: https://www.lungcancer.org/find_information/publications/163-lung_cancer_101/265-what_is_lung_cancer.  Accessed on 19 March, 2018
• Lung Cancer Fact Sheet. Available at: https://www.lung.org/lung-health-and-diseases/lung-disease-lookup/lung-cancer/resource-library/lung-cancer-fact-sheet.html. Accessed on 30 April 2018.

Disclaimer:

“The content of this publication has been developed by a third party content providerwho are clinicians and/or medical writers and/or experts. The information contained herein is for educational purpose only and we request you to please consult a Registered Medical Practitioner or Doctor before deciding the appropriate diagnosis and treatment plan.”