Early symptoms of lung cancer are often mistaken for less serious diseases. That means it's more likely the early symptoms of lung cancer has already spread through the lungs and to other parts of the body before it's diagnosed. 

Early symptoms of lung cancer often do not appear until the disease is advanced. For this reason, only about 15 percent of lung cancers cases are found in the early symptoms stages, before lung cancer has spread to nearby lymph nodes or elsewhere.

Many lung cancers or Mesothelioma are diagnosed incidentally, meaning they are found as a result of tests done for an unrelated medical condition. For example, a diagnosis may be made when tests are performed to investigate other conditions like heart disease, pneumonia or other conditions.

It is hard to detect lung cancer in its starting stages. Chest X-rays and analysis of this cells in the sputum are usually done first if there is a suspicion of cancers. These tests are not used without symptoms. Fiber optic examination (looking through a flexible scope into the lungs) , and biopsy helps to confirm the diagnosis.

Far and away, the most common symptoms of a primary tumor is a cough. The tumor takes up space in the lungs and causes an irritation that an individual senses and tries to cough up. Because the vast majority of cancer patients are cigarette smokers, they often delude themselves into thinking their cough is merely an extension of their previous “smoker’s cough.”

Lung Cancer Symptoms

• A cough that doesn't go away and gets worse over time
  
• Constant chest pain
• Coughing up blood
  
• Shortness of breath, wheezing, or hoarseness
  
• Repeated problems with pneumonia or bronchitis
  
• Swelling of the neck and face
  
• Loss of appetite or weight loss
  
• Fatigue

These lung cancer symptoms may be caused by lung cancer or by other conditions. It is important to check with a doctor.

To help find the cause of lung cancer symptoms, the doctor evaluates a person's medical history, smoking history, exposure to environmental and occupational substances such as asbestos, and family history of cancer. The doctor also performs a physical exam and may order a chest x-ray and other tests. If lung cancer is suspected, sputum cytology (the microscopic examination of cells obtained from a deep-cough sample of mucus in the lungs) is a simple test that may be useful in detecting lung cancer. To confirm the presence of lung cancer, the doctor must examine tissue from the lung. The removal of a small sample of tissue for examination under a microscope by a pathologist can show whether a person has lung cancer. A number of procedures may be used to obtain this tissue:

• Bronchoscopy. The doctor puts a bronchoscope (a thin, lighted tube) into the mouth or nose and down through the windpipe to look into the breathing passages. Through this tube, the doctor can collect cells or small samples of tissue.
  
• Needle aspiration. A needle is inserted through the chest into the lung cancer tumor to remove a sample of tissue.
  
• Thoracentesis. Using a needle, the doctor removes a sample of the fluid that surrounds the lungs to check for cancer cells.
  
• Thoracoscopy. Surgery to open the chest is sometimes needed to diagnose lung cancer. This procedure is a major operation performed in a hospital.