Radiotherapy for roentgenographically-negative lung-cancer

Ten roentgenographically-negative lung cancers were treated with radiation. All of the patients in this study were selected in a mass screening for lung cancer using sputum cytology, and their cancerous cells were confirmed as squamous cell carcinoma by bronchoscopic biopsy. Three tumors were proved to be multi-centric. Five patients were unresectable for medical reasons, three for the multi-centric occurrence, one for another advanced carcinoma and one for the refusal of surgery. The radiation field was confined into the primary tumor only, and a total dose of 6000cGy with a fraction size of 200cGy was delivered. Relapse was found in four patients; two inside the field and two outside the field. Local control rate was 75% of eight patients who were followed for more than 26 months. There was no mediastinal lymph node metastasis in seven patients. The radiation field for the roentgenographically-negative lung cancer may be confined at the primary tumor alone. However, careful follow-up should be continued because of the high incidence of multi-centric occurrence and subsequent additional lung cancer.