Lung and bronchus cancers are the leading cause of cancer death in the United States among both men and women contributing 15 % of all new cancer cases and resulting in nearly 30 % of all cancer deaths. Lung cancer can be divided into two distinct pathologies: 1) Small-cell, arising from hormonal lung cells and 2) Non-small-cell (NSCLC), consisting of squamous cell carcinomas, adenocarcinomas and broncheoalveolar carcinomas. Approximately 80% of all diagnosed lung cancers are of the non-small-cell variety.
Lung cancer is relatively rare amongst non-smokers accounting for approximately 10% to 15%2 of all lung cancer related deaths. The major risk factors are cigarette smoking and industrial exposure to many substances including asbestos, arsenic, cadmium, chromates, nickel and uranium3. In addition, a synergistic relationship exist between smoking and exposure to asbestos.
The ratio of male to female lung cancer cases is approximately 1.1 with a peak age of incidence near 601,3. The most common symptoms of localized lung cancer are persistent cough, bloody sputum and unresolved pneumonia. For locally advanced lung cancer the most common symptoms are chest wall pain and hoarseness. For distant widespread lung cancer, common symptoms include headaches, blurred vision and back pain all resulting from cancer invading distant organs.
Treatment for lung cancer is primarily determined based on disease type, disease stage and patient suitability for a particular treatment option. Treatment options fall into three main categories: (1) Surgery, (2) Radiation Therapy, and (3) Chemotherapy. More than 50% of patients diagnosed with thoracic cancer will receive radiation therapy at some point in their treatment. In fact, recent technological advances in radiotherapy treatment techniques indicate that the efficacy of radiation therapy in treating early stage NSCLC is potentially comparable to that of surgery. Some of the technological advances in radiotherapy treatment include three dimensional conformal radiotherapy (3DCRT), Intensity modulated radiotherapy (IMRT) and stereotactic body radiotherapy (SBRT).