1. Lung Cancer -- National Library of Medicine
Radiation Therapy for Lung Cancer (American Society for Therapeutic Radiology and Oncology). Radiofrequency Ablation of Lung Tumors (American College of Radiology, Radiological Society of North America).
http://www.nlm.nih.gov/medlineplus/lungcancer.html

2. Lung Cancer -- Information from Healthwise
There are two main types of lung cancer: small cell lung cancer and non small cell lung cancer. Lung cancer may spread (metastasize) to nearby lymph nodes, the other lung, or other tissues in the chest, such as the lining of the lungs or heart..
http://www.everettclinic.com/kbase/topic/major/hw183816/descrip.htm

3. Cigarette Smoking - Lung cancer -- EMedicineHealth Consumer Information
Most lung tumors are malignant. When lung cancer metastasizes, the tumor in the lung is considered the primary tumor, and the tumors in other parts of the body are called secondary tumors or metastatic tumors.
http://www.emedicinehealth.com/articles/15405-1.asp