Watch and Wait Management of Inactive Cystic Echinococcosis – Does the Path to Inactivity Matter – Analysis of a Prospective Patient Cohort

Abstract

BackgroundOverdiagnosis and overtreatment are rarely discussed in the context of NTDs despite their relevance for patients under the care of health services with limited resources where the risks of therapy induced complications are often disproportionate to the benefit. The advantages of cyst staging-based management of patients with cystic echinococcosis (CE) are not yet fully explored. Questions are: Do inactive cysts (CE 4 and CE 5) need treatment and is there a difference between cysts which reach CE4 and CE5 naturally or by benzimidazole therapy?Methodology/Principal findingsAnalysis of long-term follow-up data from a prospective CE patient cohort of 223 patients of a national clinical center for echinococcosis. The event of interest “relapse” was defined as the reversal of a cyst from an inactive stage (CE4, CE5) back to an active stage. The watch &wait (ww) group included 30 patients with 46 inactive cysts who never received medical treatment. The benzimidazole-treated (med) group included 15 patients with 17 cysts. There was no relapse in the ww-group whereas 8/17 cysts showed relapse within 18 months after treatment in the med-group. Loss to follow-up was 15.5%.ConclusionsData from the watch & wait group impressively show how stable naturally inactivated cysts are in contrast to cysts which reach inactivity through treatment with benzimidazoles. A substantial proportion of patients can be spared from treatment through cyst staging. Cysts which inactivated through a natural course do not relapse with very high likelihood. We recommend follow up of 5 years to confirm the stability of the inactive stage. Cysts driven into inactivity through benzimidazole therapy instead need careful monitoring to identify those which reactivate (around 50% within 18 months). 5 years follow-up appears safe to make a final decision on the need for further monitoring.

Watch and Wait Approach for Inactive Echinococcal Cyst of the Liver: An Update

“…4 An increasing amount of published data, reporting that spontaneously inactivated cysts remain inactive in most cases during the follow-up, support the rationale of leaving uncomplicated inactive cysts untreated, which was based on observations that a good proportion of cysts become inactive spontaneously and that cysts in general tend to remain stable over time. [6][7][8][9] The reactivation rate of cysts that become inactive spontaneously appears to be lower (0-6%) compared with that observed in cysts becoming inactive after therapy (25-60%). [6][7][8]10 Reactivation to stage CE3b, in any case, appears to occur in most cases within 2 years from first observation of inactivity.…”

“…[6][7][8][9] The reactivation rate of cysts that become inactive spontaneously appears to be lower (0-6%) compared with that observed in cysts becoming inactive after therapy (25-60%). [6][7][8]10 Reactivation to stage CE3b, in any case, appears to occur in most cases within 2 years from first observation of inactivity. 6,7,10 In 2014, we published the first report on the long-term follow-up of spontaneously inactivated hepatic cysts on a clinical rather than epidemiological basis.…”

“…[6][7][8]10 Reactivation to stage CE3b, in any case, appears to occur in most cases within 2 years from first observation of inactivity. 6,7,10 In 2014, we published the first report on the long-term follow-up of spontaneously inactivated hepatic cysts on a clinical rather than epidemiological basis. 6 In that report, 28 patients (22% of the potentially eligible patients) could not be included in the cohort because they were visited for the first time in our center less than 2 years prior, thus, not meeting the minimum follow-up length inclusion criterion.…”

Manejo clínico de la equinococosis quística hepática, estadio CE3b, combinando tratamiento médico-estrategia de vigilancia y espera: a propósito de un caso

“…En todos los casos el seguimiento imagenológico debería realizarse por períodos amplios, de por lo menos tres a cinco años (2,16,15) . De hecho, Stojkovic (18) recomienda un seguimiento de cinco años para confirmar la estabilidad de un quiste calificado como inactivo.…”

“…Stojkovic demuestra, mediante un estudio retrospectivo de quistes hidáticos inactivos, el empleo con buenos resultados de esta estrategia y propone el seguimiento mínimo de tres años con un margen de seguridad de seguimiento a cinco años. Observa que el período de reactivación de los quistes hidáticos en su estudio es inferior a los 18 meses (18) . En base a los conocimientos actuales es factible la utilización de la estrategia de vigilancia y espera en pacientes asintomáticos con quistes catalogados como estadios CE3 (CE3a o CE3b) con tratamiento médico combinado.…”