This is a hard question to answer. There are variables which affect the development of the cancer, the persons overall condition of health, the health of their immune system. Stage 4 means the cancer has spread to other organs and tissues in the body. The primary areas it spreads to are bone tissue, the brain, and the liver. I think small cell lung cancer spreads faster than non-small-cell lung cancer, I think the best answer would be between 4 and 8 months. Most of the time the cancers go undetected until it has spread for the primary site, the lung, to other organs. Signs of lung cancer are a persistent cough, blood in the sputum, recurring bouts of bronchitis or pneumonia, shortness of breath, wheezing, or hoarsness to the voice, loss of apetite or weight, fatigue or feeling tired, swelling of the face or neck, and pain in the chest, shoulder, or back. Generally, a chest x-ray is the first method of detecting lung cancer, because it is the easiest test to do when a patient presents with any of the above symptoms. Then more definitive non-invasive tools are used, CAT scan, or MRI. Both can also let you see if there is in fact metastasis of the cancer. The sad fact is, in many cancers, by the time the patient shows symptoms, the cancer may have spread. I can't express how important it is to have annual health screening. The other preventative measure is education, know what you're facing. I hope this has helped.

Some of these things do not give any symptoms My husband had pancreatic cancer and it spread to liver ,lungs , lymph system and other masses .This was before he was ever diagnosed. They say that he had probably been sick for about 2 years before his diagnosis but he had had scans and nothing diagnosed. Different cancers have different time lengths to develop and go at a different rate in different people nothing can be a definate. Every person has a different reaction to the desease