Adenocarcinoma of the lung is the most frequently occurring type of lung cancer, and lung cancer is the most common type of cancer found worldwide. The tumor arises from uncontrolled cell growth in those cells which line the respiratory passages and produce mucus. As it typically originates in peripheral lung tissue, where it is less likely to cause noticeable symptoms, adenocarcinoma of the lung often remains undiagnosed until it has reached an advanced stage where a cure is less likely. Smoking cigarettes is thought to be the main cause of lung cancer.
As well as smoking, exposure to radon gas or asbestos can also increase a person's risk of developing adenocarcinoma of the lung. The symptoms of the disease may include experiencing shortness of breath, a cough that does not go away, coughing up blood, and feeling pain in the chest. More general symptoms of cancer, such as tiredness and weight loss, can also occur, and there may be repeated chest infections. Adenocarcinoma of the lung tends to progress relatively slowly in most cases, so symptoms may not appear until the tumor has spread, or metastasized, to other parts of the body.
When adenocarcinoma of the lung metastasizes, around half of the time it will spread to the brain, with the opposite lung, the liver and bones being other possible sites. Tests used to diagnose adenocarcinoma typically include a chest X-ray, and a bronchoscopy, where a thin, flexible telescope is inserted into the lung, sending images back to the surgeon, as well as enabling samples of lung tissue to be removed. Sometimes, if a tumor cannot be reached using the bronchoscope, a needle is passed through the chest wall to obtain a sample of tissue.
If adenocarcinoma of the lung is discovered early, surgery can be used to remove the tumor, together with either a section or the whole of that lung. Most often, the cancer will already have spread to other parts of the body, in which case the treatment is chemotherapy and radiotherapy rather than surgery. Sometimes, if surgery is used, chemotherapy is given as well, in an attempt to reduce the chance of the cancer recurring.
Unfortunately, even when adenocarcinoma of the lung is diagnosed in its early stages and thought to have been completely removed, it often comes back. This can occur when a tiny number of cells, too small to be detected, have already spread or have been left behind following surgery. People can decrease their chances of developing adenocarcinoma of the lung by giving up smoking.