Human cystic echinococcosis is a chronic, complex and neglected infection. Its clinical management has evolved over decades without adequate evaluation of efficacy. Recent expert opinion recommends that uncomplicated inactive cysts of the liver should be left untreated and solely monitored over time (“watch-and-wait” approach). However, clinical data supporting this approach are still scant and published mostly as conference proceedings. In this study, we report our experience with long-term sonographic and serological follow-up of inactive cysts of the liver. From March 1994 to October 2013, 38 patients with 47 liver cysts, diagnosed as inactive without any previous treatment history, were followed with ultrasound and serology at 6–12 months intervals for a period of at least 24 months (median follow-up 51.95 months) in our outpatient clinic. In 97.4% of patients, the cysts remained inactive over time and in only one case was reactivation of the cyst detected. No complications occurred during the time of monitoring. During follow-up, serology tests for CE were negative at diagnosis or became negative in 74.1% and were positive or became positive in 25.9% of cases. Patients with inactive cysts on ultrasound but positive serological tests were also investigated by CT scan (chest and abdomen) to rule out extra-hepatic cyst localization. This study confirms the importance of a stage-specific approach to the management of cystic echinococcosis and supports the use of a monitoring-only approach to inactive, uncomplicated cysts of the liver. It also confirms that serology plays only an ancillary role in the clinical management of these patients, compared to ultrasound and other imaging techniques. The implications of these findings for clinical management and natural history of cystic echinococcosis are discussed.
Author Summary Human cystic echinococcosis (CE) is a chronic, complex and neglected parasitic infection presenting mostly as hepatic cysts, which are staged by ultrasound. Recent expert opinion recommends that uncomplicated inactive cysts should be left untreated and solely monitored over time, using the so-called “watch-and-wait” approach. Currently, no reliable biological marker of cyst activity is available. Positive antibody titers may persist for years even after removal of a cyst; therefore a long-term follow-up is required to assess the evolution of the cyst's biological activity over time. The watch-and-wait approach to inactive hepatic CE cysts is increasingly used in selected cases in referral centers; however, no data on its safety and effectiveness has yet been published. We retrospectively studied 47 inactive uncomplicated cysts at diagnosis, managed by a watch-and-wait approach, with a median follow-up of 51.95 months. We observed that these cysts remained inactive over time in almost all cases, without any complications. These results support the watch-and-wait approach to these cysts. Furthermore, we confirmed that serology only plays an ancillary role in the clinical management of these patients, compared to ultrasound and other imaging techniques.