Lung cancer is the condition characterized by the presence of uncontrolled division of lung cells. The condition, in its initial stage, does not show symptoms. However, people experience symptoms such as difficulty breathing, chest pain, and chronic cough. Type of lung cancer includes highly aggressive small cell lung cancer and less aggressive non-small cell lung cancer. Diagnosis is done through physical evaluation, imaging techniques, and biopsy. Treatment depends upon the stage and type of lung cancer and includes chemotherapy, radiation therapy, surgery, immunotherapy, and targeted therapy. Life expectancy is not favorable in patients with advanced stages of lung cancer.
What is Lung Cancer?
Lung cancer is the cancer of cells of the lungs. Although lung cancer can develop in any part of the lungs, more than 90% of cancer originates from epithelial cells. Epithelial cells make the lining of bronchi and bronchioles. Lung cancer is common cancer and risk of lung cancer increases in people who smoke.
It is also to be noted that lung cancer is most commonly diagnosed in elderly patients with age more than 65 years of age. In the US, deaths in women from lung cancer are more as compared to deaths due to breast cancer.
Symptoms of lung cancer experienced by the patient depend upon the stage of the disease. As cancer progresses, the symptoms are more severe and pronounced. In some patients, there are no symptoms until cancer reaches an advanced stage. Symptoms experienced by the patient suffering from lung cancer are:
- Hoarseness in the voice
- Difficulty breathing
- Chronic Cough
- Chest pain that becomes severe while having a deep breath, laughing and coughing.
- Recurrence of respiratory tract infection
As cancer metastasizes, the symptoms depend upon the organs where cancer has spread. Symptoms of lung cancer metastases include:
- Loss of appetite
- Weight loss without the intervention of weight loss therapies
- Clotting of blood
Types of Lung Cancer
Depending on the size of the tumor cells, lung cancer is categorized into Small cell lung cancer and Non-small cell lung cancer. The spread of disease and its prevention are different in both types of cancer.
Small Cell Lung Cancer: The most common cause of this cancer is smoking. It generally forms almost 15% of all the lung cancer. This type of cancer is highly aggressive and spread very fast in other organs. In most of the patients, the condition is diagnosed at a later stage when the disease gets metastasized. Small Cell Lung Cancer is more responsive to chemotherapy as compared to Non-Small Cell Lung Cancer.
Non-Small Cell Lung Cancer: This form remaining 85% of the total cases of lung cancer. They are not as aggressive as compared to small cell lung cancer. On the basis of the type of cell present, Non-Small Lung Cancer is divided into the following three types:
- Adenocarcinomas: This is the most common type of lung cancer and occupies about 40% of the total share. The condition is most commonly found in the peripheral region of the lungs. People who smoke are at high risk of developing adenocarcinomas.
- Squamous Cell Carcinomas: Squamous cell carcinomas are found in almost 25% of cases. This condition is also called epidermoid carcinomas. Squamous cell carcinomas are commonly found in the central part of the chest. It forms a large cavity in the lungs and may also spread to lymph nodes.
- Large Cell Carcinomas: Although, the least common form of Non-small cell lung carcinomas, this form has high potential to metastasize and may also invade the lymph nodes.
Following are some of the techniques used for diagnosing lung cancer:
On the basis of the symptoms experienced by the patient, the pulmonologist may try to ascertain the cause of such symptoms. To rule out the presence of cancer, the doctor may advice certain tests.
Imaging techniques may be used to identify the presence of cancer, staging and the level of metastasis. Imaging techniques used are X-ray, CT Scan, PET scan, and bone scan.
Techniques such as mediastinoscopy are used to perform a biopsy. A small sample of tissue is obtained and tested for cancer. Biopsy of lump nodes can also be done.
Staging of Small cell lung cancer and non-small lung cancer is done in the following ways:
Small Cell Lung Cancer:
- Limited stage: At this stage, the cancer is limited to one side of the lungs and involves just one part and lymph nodes.
- Extensive stage: This stage is more advanced with cancer spreading in other parts of the chest and also spread to other organs.
Non-Small Cell Lung Cancer:
- Stage I: The cancer is limited only to the lungs and the surrounding lymph nodes are not affected by cancerous cells.
- Stage II: Cancer is present in the lungs and the lymph nodes.
- Stage III: If the cancer is present in the lungs and the lymph nodes present in the middle of the chest. If cancer has spread to the lymph nodes present on the same side from which cancer is intuited, the stage is IIIA, while if cancer spreads to the lymph nodes present on the opposite side, the stage is designated as IIIB.
- Stage IV: This is the most advanced stage of lung cancer. Cancer has invaded the whole of the lungs, the surrounding lymph nodes, the fluid and has also metastasized to other organs.
Various treatment options are available for lung cancer treatment. The treatment option used depends upon the severity of the disease and the type of lung cancer. For small cell carcinomas, due to their aggressive nature, a combination of radiation therapy and chemotherapy is recommended while in cases of non-small cell lung carcinoma, surgery is recommended as this cancer takes a lot of time in affecting organs outside lungs. Lobectomy is the surgery in which the entire lobe of the lungs is removed. Radiofrequency ablation and microwave ablation are the processes of treating lung cancer in which heat is produced through different sources for killing cancer cells. Treatment options for lung cancer include:
- Radiation Therapy
- Targeted therapy
- Microwave ablation
Lung Cancer Life Expectancy
The survival rate of lung cancer depends upon the stage at which the condition is diagnosed. Diagnosis at an advanced stage reduces the chances of survival. The 5-year survival rate for localized small cell lung cancer is 60% while it is only 6% if the condition reached the extensive stage. Without treatment, the extensive stage patients live for only 2-3 months while with treatment, life can be extended up to around one year. The survival rate for stage I non-small cell lung cancer is about 49% while the 5-year survival rate of stage IV is just 1-2 percent.
Lung cancer is a highly fatal condition. In most of the patients, because of the non-appearance of symptoms, the cancer is diagnosed in an advanced stage. Treatment depends upon the stage of the disease. Patient with the less severe condition has high rest of survival. The patient who is at high risk such as smokers should undergo scheduled screening to diagnose the condition at an early stage.