Objectives Mesonephric adenocarcinoma (MA) or mesonephric-like adenocarcinoma (MLA) is a rare tumor of the endometrium arising from regressed mesonephric duct. However, there is still a lack of evidence about their prognostic factors because of the rarity. Thus, we investigated prognostic factors of MA or MLA through the analysis of rare case series by using published reports.

Methods This study is a secondary analysis utilizing published literature. Through extensive search using PubMed, EmBase and the Cochrane database, 65 patients with either MA or MLA were identified between years 1995 and 2020. A total of 72 patients were finally included after adding seven patients diagnosed with MA or MLA in our institute between 2000 and 2020. We evaluated clinicopathologic characteristics of all patents, and investigated prognostic factors affecting progression-free survival (PFS).

Results Patients with early-stage disease (n=41) had longer mean PFS than those with advanced-stage disease (n=31) (39 vs 14 months, p<0.01). Moreover, patients with tumor size ≤5 cm (n=16) had longer mean PFS that those with tumor size >5 cm (n=15; 49 vs 13 months; p<0.01). Univariate analyses revealed that advanced-stage disease, tumor size >5 cm and no systemic chemotherapy were factor affecting PFS (hazard ratios [HRs], 3.27, 5.88, 4.34; 95% confidence interval [CIs] 1.56–6.84, 1.26–27.33, 1.74–10.85. Finally, tumor size >5 cm was the only prognostic factor of worse PFS in multivariate analyses (HR 5.49; 95% CI 1.15–26.18).

Conclusions Tumor size >5 cm may be associated with worse PFS of MA or MLA of the endometrium.