PurposeShort-term results have been reported regarding parastomal hernia (PH) prevention with a permanent mesh. Long-term results are scarce. The objective was to assess the long-term PH occurrence after a prophylactic synthetic non-absorbable mesh.MethodsLong-term data of three randomized controlled trials (RCTs) were collected. The primary outcome was the detection of PH based exclusively on a radiological diagnosis by computed tomography (CT) performed during the long-term follow-up. The Kaplan–Meier method was used for the comparison of time to diagnosis of PH according to the presence of mesh vs. no-mesh and the technique of mesh insertion: open retromuscular, laparoscopic keyhole, and laparoscopic modified Sugarbaker.ResultsWe studied 121 patients (87 men, median age 70 years), 82 (67.8%) of which developed a PH. The median overall length of follow-up was 48.5 months [interquartile range (IQR) 14.4–104.9], with a median time until PH diagnosis of 17.7 months (IQR 9.3–49.0). The survival analysis did not show significant differences in the time to development of a PH according to the presence or absence of a prophylactic mesh neither in the overall study population (log-rank,P= 0.094) nor in the groups of each technique of mesh insertion, although according to the surgical technique, a higher reduction in the appearance of PH for the open retromuscular technique was found (log-rank,P= 0.001).ConclusionIn the long-term follow-up placement of a non-absorbable synthetic prophylactic mesh in the context of an elective end colostomy does not seem effective for preventing PH.