RADIOTHERAPY FOR ROENTGENOGRAPHICALLY-NEGATIVE LUNG-CANCER

Ten roentgenographically-negative lung cancers were treated with radia tion. All of the patients in this study were selected in a mass screen ing for lung cancer using sputum cytology, and their cancerous cells w ere confirmed as squamous cell carcinoma by bronchoscopic biopsy. Thre e tumors were proved to be multi-centric. Five patients were unresecta ble for medical reasons, three for the multi-centric occurrence, one f or 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 f ield. Local control rate was 75% of eight patients who were followed f or more than 26 months. There was no mediastinal lymph node metastasis in seven patients. The radiation field for the roentgenographically-n egative lung cancer may be confined at the primary tumor alone. Howeve r, careful follow-up should be continued because of the high incidence of multi-centric occurrence and subsequent additional lung cancer.