Four hundred forty-eight patients with 929 Echinococcus granulosus hydatid
cysts received 3- to 6-month continuous cycles of mebendazole or albendazol
e treatment and underwent prolonged follow-up by clinical visits and imagin
g studies (range, 1-14 years) to assess the long-term outcome of treatment.
Degenerative changes and relapse were assessed by imaging techniques. At t
he end of therapy, 74.1% of the hydatid cysts showed degenerative changes.
These were more frequent in albendazole-treated than in mebendazole-treated
cysts (82.2% vs. 56.1%; P < .001). During longterm follow-up, 104 cysts (2
2%) had degenerative changes that progressed, whereas 163 cysts (similar to
25%) relapsed. The percentages of relapses in the two drug-treated soups w
ere almost the same. Relapses occurred more frequently in type II cysts of
the liver. Cysts recurred most often (78.5%; P < .001) within the first 2 y
ears after treatment ended. Further chemotherapy cycles induced degenerativ
e changes in >90% of relapsed cysts without inducing more frequent or more
severe side effects than those observed during the initial cycles.