Causes of Lung Cancer
Lung cancer is the most common cancer in the Western world, killing millions of patients worldwide every year. There are approximately 46 000 new lung cancer cases diagnosed yearly in the UK. The main cause of lung cancer is smoking but other agents have been implicated as causes of lung cancer (asbestos, radon, radiation).
Surgical resection is considered the best treatment when feasible and offers the best chance of cure particularly in early-stage disease. Unfortunately, only 20 to 25% of patients can have an operation following a diagnosis of lung cancer, the majority of patients being diagnosed with inoperable cancer (spread) or being not fit for an operation.
The percentage of patients having surgery for lung cancer is less than 20% in the UK, one of the lowest resection rates in Europe. When surgery is not feasible, the cancer can be treated by radiotherapy (external beam radiation), chemotherapy (drugs given orally or intravenously at regular intervals) or both, targeted therapy (smart drug targeting specific cancer cells) and immunotherapy.
Lung metastases (secondary lung cancer) are not uncommon following resection of colon carcinoma, renal cell carcinoma, breast carcinoma, malignant melanoma (skin cancer), breast carcinoma and sarcomas (cancer of connective tissue). In selected cases, lung metastases are removed surgically.
New treatment modalities are available (radiofrequency ablation and cyberknife radiosurgery) in certain cases. Chemotherapy is usually administered before or after these procedures to reduce the risk of relapse. Studies are ongoing to define the role of immunotherapy alone or in association with other therapies (radiotherapy, chemotherapy) in lung cancer and other thoracic malignancies.