Metastatic cancer of the lungs is the condition in which the cancer spreads from various parts of the body to the lungs through blood or lymph. Benign tumors on the other hand do not spread, and are easy to remove. Malignant tumors are aggressive by nature, and they invade nearby lymph nodes, tissues, and organs. They can even attack and destroy distant organs. When the malignant tumor that originated in the lung spreads to other sites, the condition is referred to as 'metastatic lung cancer'. As the cancer metastasizes, it is referred to as advanced stage cancer. Metastasis of lung cancer takes place during stage III and IV.
Symptoms of Advanced Stage
Smoking or exposure to tobacco (passive smoking), air pollution, exposure to asbestos, familial predisposition, etc., increase the risk of developing lung cancer. Studies show that in about 90-95% cases, lung cancer develops in the cells present in the lining of the bronchi and bronchioles (airways). It may also develop in the pleura (mesotheliomas) or the supporting tissues or blood vessels. The cancer spreads to other body parts relatively more quickly, once it is formed. Metastasis of the cancer can be seen in any part of the body, but the most common sites of metastasis are bones, brain, liver, and adrenal glands. As the function of the lungs is to purify the blood which is supplied to various parts of the body, chances of metastasis of lung cancer are comparatively high.
Early signs of lung cancer are more likely to go unnoticed, as the symptoms can be misunderstood. In the preliminary or early stage, symptoms like chronic cough, breathing difficulty, blood in sputum, pain in the chest, shoulders, arms or back, bronchitis or prolonged pneumonia, lung infection, loss of appetite, joint pain, etc. can be present. However, in some patients no symptoms are noticed until the cancer gets detected in routine tests or x-rays.
When the cancer spreads to the adjoining tissues or structures, or to distant bones, following symptoms can be seen.
- Constant cough
- Wheezing, breathing difficulty
- Blood in sputum
- Chest pain
- Shoulder pain
- Pain in the arm
- Dysfunction of vocal cords resulting in hoarseness
- Damage to some part of the lung leads to increased number of lung infections, abscesses, etc.
- Excessive weight loss
- Excessive fatigue
- Mood swings, depression
- Difficulty swallowing
- Excruciating pain at the sites where the cancer has spread into bones
- Overproduction of hormone cortisol by the adrenal glands (Cushing's syndrome)
- High blood calcium levels
- When the cancer spreads into the brain, symptoms like blurred vision, headaches, and seizures are observed.
Lung cancer is one of the most difficult cancers to treat. Doctors check the symptoms, chest X rays, CT scans, bone scans, test results (for example, sputum cytology), biopsy reports and then determine the treatment. Since the cancer has spread to other parts of the body, it is difficult to remove the cancer surgically. It is even difficult to control the growth of cancer. Depending upon the symptoms and the extent to which the cancer has spread in the body, chemotherapy and radiation therapy are recommended. Metastatic lung cancer treatment may result in short-term memory problems, fatigue, nausea, vomiting, hair loss, and other side effects. When the cancer is in the advanced stage, treatment is focused on lowering the pain experienced by the patient.
The 5-year survival rate for lung cancer is about 16% which is very low when compared to other cancers. The prognosis of this condition is very poor, as the survival rate for advanced stage is very low. Survival time of untreated patients of advanced stage is only 2-4 months after diagnosis, as this is a fast-spreading cancer. With treatment, the survival time can be extended for a few months. If the condition is diagnosed at the early stage, then the survival rate may extend up to 5 years or more. Routine checkup is therefore necessary as it helps detect serious diseases and disorders at an early stage, and thus helps increase the life expectancy of the patient.