The purpose of this study is to determine if photodynamic therapy (PDT) is an alternative to surgical resection in patients with early stage) roentgenographically occult squamous cell carcinoma of the lung who are candidates for surgery. If PDT is successful, it would remove the indication for surgery and eliminate the need for an operation. The specific goals are to evaluate the impact of PDT on these patients by determining the percentage of patients who are spared surgery as wel1 as the following: morbidity, overall mortality, lung cancer mortality, the rate of subsequent lung cancer, the relative cost of PDT and surgery, the change in pulmonary function over time, the effect on quality of life, and the patient preferences for PDT and surgery.