Impact of Safe Distance on Long-Term Outcome After Surgical Therapy of Alveolar Echinococcosis

In humans, alveolar echinococcosis (AE) is a serious helminthic disease. Additionally to a long-term medical treatment, in all suitable cases a complete surgical resection with a 20-mm safe distance (minimal distance of larval tissue to resection margin) is recommended. We analyzed the influence of the safe distance and the effect of the postoperative anthelmintic prophylaxis on the long-term outcome of patients who underwent surgery with curative intent.

Ninety-two operated patients were evaluated regarding the safe distance, the duration of medical therapy with benzimidazole derivates, and the further course of AE.

Median follow-up after surgical procedure was 8.3 years. Twelve patients had a safe distance of 20 mm or more, 16 patients between 10 and 19 mm, 21 patients between 1 and 10 mm, and 10 patients 1 mm. In a further 33 patients, the affected liver was resected without any safe distance. Recurrence of AE was seen in 15 patients between 4 months and 24 years after initial operation. Safe distances of patients with recurrent disease were: 13 ×  no safe distance, one patient with 1-mm and one patient with 13-mm safe distance. In all patients except one with recurrent AE, postoperative therapy with benzimidazole derivates was stopped.

A safe distance of at least 1 mm in combination with medical anthelmintic treatment continuing for two years might offer a good chance of being disease-free long term, but the exact period of medical treatment needed is not defined. The therapy regime should be determined through an interdisciplinary approach in specialized centers.