A comparative evaluation of lymphoscintigraphy versus lymphangiography and computerized tomography scanning in diagnosis of lymph node metastases in advanced bladder cancer.

The potential of lymphoscintigraphy to detect lymph node metastases compared to lymphangiography and computerized tomography scanning was evaluated in 26 patients who underwent radical cystectomy for invasive bladder cancer. Four-view images of the abdominoperineal area were taken 90 to 120 minutes after 99mtechnetium-rhenium sulfide was injected into 2 interdigital spaces in each foot. Results of lymphoscintigraphy interpretation correlated with surgical and histological findings: a correct diagnosis was made in 61.5 per cent of the patients, while 23.1 per cent had false positive and 15.4 per cent had false negative results. Although computerized tomography was the most accurate method to detect lymph node metastases (correct diagnosis in 73.1 per cent of the patients) no significant difference was found among the 3 diagnostic methods. False positive interpretation of lymphoscintigraphy was twice as common as that of the radiological studies (23 versus 11.5 per cent). The possibilities that may cause image variation interpreted as a false positive result are discussed. Because lymphoscintigraphy is an easier and less time-consuming study than lymphangiography, the former method is suggested to be an additional and sometimes (for example if short-term followup studies are required) preferred modality to evaluate the extent of lymph node involvement in cases of invasive bladder cancer.