OBJECTIVE: This study evaluates the statistical robustness of the ISAP cutoff proposed by the 2025 guidelines, re-assesses traditional pathological prognostic factors, and identifies candidates for therapeutic de-escalation regarding chemotherapy omission and fertility-sparing surgery (FSS). METHODS: We harmonized an institutional cohort (2015-2021, N = 36) with a systematic literature review (1990-2021, N = 193). Missing data were handled via multiple imputation. The optimal ISAP cutoff was determined using AIC/BIC; prognostic factors were evaluated via multivariate Cox regression. RESULTS: Among 229 patients (50 [21.8%] undergoing FSS), ISAP ≥48 months emerged as the optimal cutoff, stratifying 174 low-risk (ISAP <48 months) and 31 high-risk patients. ISAP ≥48 months independently predicted progression-free survival (HR 14.92, 95% CI 3.68-60.38; P < 0.001) and overall survival (HR 20.90, 95% CI 2.22-196.73; P = 0.008). Pathological risk factors showed no prognostic significance. Among low-risk patients managed without chemotherapy, no progression or mortality events occurred (0/85). Four (8.0%) FSS patients required salvage hysterectomy; all achieved 100% survival and none required completion hysterectomy after childbearing. CONCLUSIONS: ISAP ≥48 months is a robust prognostic determinant in Stage I PSTT. Surgery alone achieved excellent outcomes in low-risk patients; prospective trials should confirm whether chemotherapy can be safely omitted. FSS is viable for strictly selected low-risk candidates, with salvage hysterectomy providing effective control and subsequent term pregnancies documented.