Adjuvant Treatment for Grade 2 Endometrioid Endometrial Carcinoma with 46% Myometrial Invasion
No, adjuvant cisplatin-based chemoradiation should NOT be given for this patient. This case represents intermediate-risk disease (Stage IA, Grade 2, <50% myometrial invasion, LVSI negative), and observation or vaginal brachytherapy alone are the appropriate evidence-based options 1.
Risk Classification
Your patient falls into the intermediate-risk category based on the 2016 ESMO-ESGO-ESTRO consensus classification 1:
- Stage I endometrioid histology
- Grade 1-2
- <50% myometrial invasion (46% is below the 50% threshold)
- Assuming LVSI negative (as stated "no other high-risk factors")
This is explicitly NOT high-risk disease, which requires ≥50% myometrial invasion for Grade 2 tumors 1.
Evidence-Based Treatment Recommendations
For intermediate-risk endometrial cancer, observation alone is the standard of care 1. The PORTEC-1 and GOG99 trials established that adjuvant pelvic radiotherapy significantly reduces pelvic/vaginal relapses but has no impact on overall survival in this risk group 1.
Treatment Options in Order of Preference:
Observation alone - This is appropriate and supported by Level I evidence 1
Vaginal brachytherapy - May be considered if the patient has additional risk factors within the intermediate-risk category (age ≥60 years), though this still does not change the risk classification to high-risk 2
Why Chemoradiation is NOT Indicated
Cisplatin-based chemoradiation is reserved for high-risk disease, defined as 1:
- Stage I endometrioid, Grade 3, ≥50% myometrial invasion
- Stage II disease
- Stage III without residual disease
- Non-endometrioid histology (serous, clear cell)
Your patient meets none of these criteria. The combined analysis of NSGO 9501/EORTC 55991 and MaNGO-ILIADE III trials showed benefit of adding chemotherapy to radiotherapy only in high-risk patients, not intermediate-risk 1.
Critical Distinction: Myometrial Invasion Threshold
The 50% myometrial invasion threshold is the critical dividing line 1:
- <50% invasion (your patient at 46%) = Intermediate risk → Observation or vaginal brachytherapy
- ≥50% invasion = Would elevate to high-intermediate or high-risk depending on grade and LVSI status
At 46% myometrial invasion, this patient remains below the threshold that would justify more aggressive therapy 1.
Common Pitfall to Avoid
Do not conflate "close to 50%" with "≥50%". The evidence-based risk stratification uses ≥50% as a hard cutoff 1. Overtreatment with chemoradiation in intermediate-risk disease exposes patients to significant toxicity (gastrointestinal, hematologic) without survival benefit 1.
Confirmation of Staging Requirements
Ensure comprehensive surgical staging was performed, including assessment of LVSI status 1. If LVSI is unequivocally positive, this would reclassify the patient to high-intermediate risk even with <50% invasion, potentially warranting vaginal brachytherapy 1, 2. However, the question states "no other high-risk factors," which implies LVSI negative.