Evaluation of response to chemotherapy of human cystic echinococcosis.

Fifty-five patients with echinococcosis were treated with mebendazole (30) and albendazole (25). To determine changes in cyst morphology and to evaluate the varying degree of response, progress during follow-up was shown by radiography, computerized tomography and ultrasonography. Persistence of cysts without any change in the morphology and cyst enlargement were taken as criteria for unsuccessful treatment. Development of echogenic foci and increase in density of cyst fluid were considered as a therapeutic effect. Changes in cyst wall such as thickening and deposition of calcium and detachment of the cyst membrane may also indicate response. An essential criterion, for a positive drug effect, was cyst size reduction as well as shape deformation. However, the most convincing and reliable criterion was the complete disappearance of hydatid cysts. Comparative assessment of the therapeutic effect of the two drugs favoured albendazole.