BACKGROUND: Hepatectomy is the first-line treatment for alveolar echinococcosis (AE) if complete resection is feasible. However, a strategy for the treatment of patients with AE in whom the tumor cannot be resected completely remains to be defined. STUDY DESIGN: Data were retrospectively collected from 188 consecutive patients between 1984 and 2009. Overall survival (OS), progression-free survival (PFS), and risk factors were analyzed in patients classified into 3 groups (group A: complete resection, group B: reduction surgery, and group C: drainage or exploratory laparotomy). RESULTS: In group A (n = 119), the 10-, 15-, and 20-year OS was 98.9%. In group B (n = 63), the 10-, 15-, and 20-year OS was 97.1%, 92.8%, and 61.9%. In group C (n = 6), the 10- and 15-year OS was 50.0% and 33.3%. Patients in groups A and B had better prognoses than those in group C (p < 0.001). In group A, the 10-, 15-, and 20-year PFS was 96.5%, 94.4%, and 94.4%. In group B, the 10-, 15-, and 20-year PFS was 87.1%, 71.6%, and 61.4%. In group C, the 10- and 15-year PFS was 50.0% and 33.3%. Patients in group A had better PFS than those in groups B and C (p < 0.001). Curability was the only independent factor for both OS and PFS by multivariate analysis. CONCLUSIONS: Although the most effective therapy for AE is complete resection, a better prognosis can be achieved by reduction surgery and/or adjuvant albendazole therapy for patients with AE that cannot be completely resected. (J Am Coll Surg 2011;212:804-812. (C) 2011 by the American College of Surgeons)