Background
Phase III randomized trial, POLE-mutated endometrial cancer patients, stage I-II, molecular-integrated risk-guided approach, comparison of de-escalated adjuvant therapy vs standard RT based on molecular profiling
Interventions and follow up
Arm A: No adjuvant therapy (de-escalation for favorable POLE mutation with pathogenic mutation defined)
Arm B: Adjuvant radiotherapy (standard care)
Primary endpoint: Recurrence-free survival with de-escalation in POLE-mutated (favorable) vs other subtype
mFollow up: Extended follow-up ongoing
Arm B: Adjuvant radiotherapy (standard care)
Primary endpoint: Recurrence-free survival with de-escalation in POLE-mutated (favorable) vs other subtype
mFollow up: Extended follow-up ongoing
Results
De-escalation safety: Omission of adjuvant RT safe in POLE-mutated stage I-II with favorable features (high grade, deep invasion, LVSI acceptable; not prognostic)
Recurrence rates: POLE-mutated cancers show excellent outcomes even with de-escalation; 5-year RFS >95%
Recurrence rates: POLE-mutated cancers show excellent outcomes even with de-escalation; 5-year RFS >95%
Adverse events
Main adverse events: Favorable toxicity profile with de-escalation (no RT toxicity in omitted group). Long-term outcomes excellent with molecular risk stratification.
Conclusions
PORTEC-4a prospectively validates de-escalation of adjuvant RT for POLE-mutated endometrial carcinoma, demonstrating safety of omitting treatment in carefully selected patients. Establishes molecular profiling as essential for individualizing therapy and reducing overtreatment.
Key Limitations
Key Limitations: Requires accurate POLE mutation identification (11 pathogenic mutations only); multiple classifiers (POLE + p53 abnormalities or mismatch repair deficiency) need special consideration. Advanced stage POLE-mutated cancers remain uncommon, data limited.
Clinical Context
PORTEC-4a landmark trial shifts endometrial cancer paradigm toward molecular de-escalation. Supports omission of RT in low-risk POLE-mutated tumors, reducing radiation toxicity while maintaining excellent outcomes. Informs molecular testing strategy at diagnosis.
References