Clinicopathologic correlations demonstrating the failure of 67gallium scanning in determining response to radiotherapy.

Scanning of the chest using radioactive 67gallium citrate was performed in 12 patients with stage 3MO bronchogenic carcinoma prior to and following preoperative radiotherapy (3,000 rads). This was done to determine if scanning with 67gallium would be predictive in determining radiotherapeutic response. All 12 patients underwent resection of their primary bronchogenic carcinoma, and comparisons of chest x-ray films and 67gallium scans obtained before and after irradiation and of surgical specimens were made. The scan using 67gallium showed improvement in nine of the 12 patients; however, in five of these nine patients, the improvement on the scan using 67gallium was not paralleled by objective regression of the tumor on the chest x-ray film. Viable tumor was observed in the resected specimen in all 12 patients. We conclude that a scan with 67gallium should not be used to evaluate radiotherapeutic response.