Lung Cancer or Carcinoma of the Lung: Causes, Types, Risk Factors, Symptoms, Signs, Investigations, Treatment, Stages
Cancer beginning in the lungs is known as Lung Cancer (Carcinoma of the Lung.) Lungs are located in our chest and help with the function of breathing by taking in oxygen when inhaling and releasing carbon dioxide when exhaling.
Smokers are at the highest risk for having lung cancer and this risk increases with the duration of the time and the amount of cigarettes smoked. Quitting smoking significantly reduces the chances of having lung cancer. Treatment options include surgery, radiation therapy, chemotherapy and targeted drug therapy.
Causes of Lung Cancer or Carcinoma of the Lung
The main cause of lung cancer is smoking. Smoking causes lung cancers both in smokers, as well as individuals who are exposed to secondhand smoke. However, it is also possible for individuals who have never smoked to develop lung cancer. For such cases, the cause for lung cancer is not clear.
Types of Lung Cancer or Carcinoma of the Lung
Based on the appearance of the lung cancer cells, the lung cancer is divided into two important types:
- Small Cell Lung Cancer: This type of cancer occurs almost only in heavy smokers.
- Non-Small Cell Lung Cancer: This type of cancer is a broad term for various types of lung cancers which act in a similar manner. Non-small cell lung cancers are more common and include adenocarcinoma, squamous cell carcinoma and large cell carcinoma.
Risk Factors for Lung Cancer or Carcinoma of the Lung
- Smoking by far is the biggest risk factor for developing lung cancer.
- The risk of developing a lung cancer is more in individuals who are exposed to secondhand smoke.
- The risk also increases upon exposure to radon gas.
- Individuals who are exposed to chemicals such as asbestos, arsenic, nickel and chromium are at a higher risk for developing lung cancer.
- Having a family history (parents, siblings) of lung cancer increases the chances to develop lung cancer.
Signs and Symptoms of Lung Cancer or Carcinoma of the Lung
Symptoms usually do not appear in the initial stages. Symptoms in the advanced stage include:
- Recent and persistent cough.
- Any changes in an old/chronic cough or a "smoker's cough."
- Coughing up blood.
- Wheezing sounds from the chest.
- Pain in the chest.
- Hoarseness of the voice.
- Pain in the bones.
- Unintentional weight loss.
Investigations for Lung Cancer or Carcinoma of the Lung
- X-rays and CT Scan help in detecting abnormal mass, nodule or small lesions in the lungs.
- Sputum Cytology: In this, the sputum is tested under the microscope to look for lung cancer cells.
- Biopsy is taking a tissue sample and sending it to lab for testing for cancer cells.
- Bronchoscopy is a test where the abnormal regions of the lungs are examined with the help of a lighted tube which is passed via throat and into the lungs.
- Mediastinoscopy is a procedure where an incision is made above the sternum, at the base of the neck. Next surgical tools are introduced posterior to the breastbone and biopsy is taken from the lymph nodes.
Staging Tests for Lung Cancer or Carcinoma of the Lung
- CT scans
- Magnetic Resonance Imaging (MRI)
- Positron Emission Tomography (PET)
- Bone Scans.
Stages of Lung Cancer or Carcinoma of the Lung
- Stage I: In this stage, the cancer is confined to the lung and hasn't metastasized to the lymph nodes. The tumor is usually lesser than 2 inches in width.
- Stage II: In this stage, the cancer tumor is larger than 2 inches; or there may also be a smaller tumor infiltrating the adjacent structures, such as the diaphragm, chest wall, or the pleura. Cancer could have also spread to the lymph nodes present nearby.
- Stage III: In this stage, the tumor has grown quite large and has also infiltrated the nearby organs; or in this stage, there may be smaller tumors with cancer cells which have metastasized to the distant lymph nodes.
- Stage IV: In this stage, the cancer has metastasized beyond the affected lung to the healthy lung or to the faraway areas of the body.
Treatment of Lung Cancer or Carcinoma of the Lung
Treatment of lung cancer is done depending on the patient's overall health, the stage and type of the lung cancer and the patient's treatment preferences.
Surgery for Lung Cancer or Carcinoma of the Lung
- Wedge Resection: In this procedure, a small portion of the lung, which contains the tumor, is removed along with a margin of normal, healthy tissue.
- Segmental Resection: In this procedure a large segment of the lung is removed.
- Lobectomy: This procedure entails removal of the complete lobe of a single lung.
- Pneumonectomy: In this procedure, the entire lung is removed.
During surgery, the lymph nodes from the chest may also be removed to check them for cancer cells. The risks of lung cancer surgery include bleeding and infection. Side effects include shortness of breath.
Chemotherapy for Lung Cancer or Carcinoma of the Lung
Chemotherapy is that treatment modality which uses chemicals or drugs to destroy cancer cells. One or more chemotherapy drugs can be given either intravenously or orally in a pill form. Chemotherapy is commonly used after surgery to destroy any remaining cancer cells. It can also be done before surgery so the cancer gets shrunk in size and is easier to remove. In some patients, chemotherapy is also done to alleviate pain and other advanced cancer symptoms.
Radiation Therapy for Lung Cancer or Carcinoma of the Lung
- Radiation therapy involves the use of high-powered energy beams which are directed at specific points of the body to kill cancer cells. External beam radiation is that radiation therapy where the beams are directed outside your body.
- Brachytherapy is where the radiation is targeted inside the body by placing it in seeds, needles or catheters and keeping them within your body near the cancer site.
- Radiation therapy can be done after surgery to destroy any remaining cancer cells. Radiation therapy can also be done as the initial treatment where the lung cancer can't be excised during the surgery. In patients having advanced lung cancer, radiation therapy helps in alleviating pain and other cancer symptoms.
- Stereotactic body radiotherapy is an option for those people who have lung cancers which are quite small. This type of radiation aims multiple radiation beams from different angles targeted at lung cancer.
- Stereotactic body radiotherapy treatment can also be used instead of surgery if the tumors are small.
Targeted Drug Therapy for Lung Cancer or Carcinoma of the Lung
These are the latest cancer treatments which work by targeting only the specific abnormalities in the cancer cells. Drugs used for targeted therapy for treating lung cancer are:
- Avastin/Bevacizumab: This medicine prevents the formation of new blood supply to the tumor thus preventing the growth of the tumor. Bevacizumab is often used in conjunction with chemotherapy and done for recurrent and advanced non-small cell lung cancer. The risks of Bevacizumab includes: hypertension, bleeding and blood clots.
- Tarceva/Erlotinib: This drug blocks the chemicals which signal the cancer cells to divide and grow. Erlotinib is appropriate for patients having advanced and recurrent non-small cell lung cancer with a particular genetic mutation. Side effects of this drug includes: diarrhea and skin rash. Erlotinib benefits non smokers more than smokers.
- Xalkori/Crizotinib: Crizotinib blocks the chemicals which permit the rapid dividing and growth of the cancer cells. Crizotinib is appropriate for patients with advanced non-small cell lung cancer with a specific genetic mutation. Side effects include vision disturbances (blurry or double vision) and nausea.
Palliative Care for Lung Cancer or Carcinoma of the Lung
Palliative care or supportive care is that branch of medicine, which tries to alleviate the signs and symptoms of lung cancer. It is recommended that the patient meet with a palliative health care team after the diagnosis of lung cancer, so that the patient is comfortable during and after the treatment for cancer. Patients receiving palliative care after the diagnosis of cancer and patients with advanced non-small cell lung cancer have better quality of lives with better mood. Patients receiving palliative care also live longer than patients who receive standard care for cancer.