Stage IA Grade 1 Endometrioid Endometrial Cancer: Excellent Prognosis
Women with stage IA grade 1 endometrioid endometrial cancer have an excellent five-year disease-specific survival of approximately 97-98%, with overall survival of 89-96%, and recurrence rates of only 3-8%. 1, 2, 3
Five-Year Survival Data
The prognosis for this specific patient population is exceptionally favorable:
- Five-year disease-specific survival: 97.3% in a prospective Danish nationwide study of 571 stage IA patients 2
- Five-year overall survival: 88.9-96.4% across multiple large cohort studies 2, 3
- Five-year survival for all stage IA disease: 89.6% based on the FIGO 2009 staging system 1
The ESMO guidelines emphasize that endometrial cancer generally carries a favorable prognosis, with European age-adjusted 5-year relative survival reaching 78% overall, and this excellent outcome is primarily driven by early-stage detection 1
Recurrence Risk Profile
The recurrence risk for stage IA grade 1 disease is remarkably low at 3-8%, with most recurrences occurring within the first 2-3 years after surgery 4, 2, 3:
- Overall recurrence rate: 3.9-7.7% in surgically staged patients without adjuvant therapy 4, 2
- Vaginal recurrences comprise 65% of all recurrences in stage IA disease, which are often salvageable with radiation therapy 2
- Death from recurrence occurs in only 39% of those who recur, translating to approximately 1-3% cancer-specific mortality 2
Critical Prognostic Modifiers Within Stage IA Grade 1
Even within this low-risk category, specific pathologic features significantly impact recurrence risk 4, 5:
- Any myometrial invasion versus no invasion increases 3-year recurrence from 2% to 18% (p=0.004) 4
- Tumor size ≥2 cm increases 3-year recurrence from 2% to 15% (p=0.021) 4
- Lymphovascular space invasion (LVSI) reduces 5-year overall survival from 88% to 64% when present 1
- Time from biopsy to surgery ≥6 months dramatically increases 3-year recurrence to 54% versus 8% (p=0.003) 4
Important Clinical Context
Grade Concordance Issues
Approximately 30% of patients with preoperative grade 1 diagnosis will be upstaged to grade 2 or 3 on final pathology, and 12.6% will have advanced-stage disease (stage III-IV) 3. This underscores the critical importance of complete surgical staging rather than relying solely on preoperative biopsy results 6, 3.
Recommended Treatment Approach
According to ESMO guidelines, observation alone is the standard recommendation for stage IA grade 1-2 endometrioid cancer without adverse risk factors 1, 7. The NCCN and ACOG classify this as low-risk disease with approximately 10.4% recurrence risk, requiring no adjuvant therapy 7, 6.
However, if additional adverse factors are present (LVSI, tumor size ≥2 cm, any myometrial invasion), consideration of vaginal brachytherapy may be warranted, though this reduces local recurrence without improving overall survival 7, 8.
Common Pitfalls to Avoid
- Do not rely on preoperative biopsy grade alone for treatment planning, as 30% will have grade discordance on final pathology 3
- Do not delay surgery beyond 6 months from diagnosis, as this independently predicts significantly higher recurrence rates 4
- Do not assume all stage IA grade 1 patients have identical prognosis—myometrial invasion, tumor size, and LVSI create meaningful risk stratification even within this favorable group 4, 5
- Do not recommend routine adjuvant radiation for truly low-risk disease (no myometrial invasion, no LVSI, tumor <2 cm), as randomized trials show no survival benefit and only marginal reduction in already-low recurrence rates 7