Table 1_Deep cervical stromal invasion predicts poor prognosis in endometrioid endometrial cancer with cervical stromal involvement: a risk-stratification model for adjuvant therapy decision-making in endometrial carcinoma.docx

Multivariable Cox regression identified independent prognostic factors. A weighted four-factor risk score was developed incorporating deep CSI (2 points), G3 histology (1 point), substantial lymphovascular space invasion (LVSI, 1 point), and p53-aberrant subtype (1 point). Propensity score-matched analysis (1:1 matching) evaluated external beam radiotherapy (EBRT) efficacy in deep CSI patients.</p>Results<p>Deep CSI was present in 71 patients (17.2%) and was associated with aggressive pathological features: higher grade (G3: 35.2% vs. 18.5%, P = 0.003), deeper myometrial invasion (≥50%: 67.6% vs. 34.9%, P < 0.001), and substantial LVSI (33.8% vs. 12.9%, P = 0.002).

Deep CSI independently predicted 3-year recurrence (adjusted HR 2.45, 95% CI 1.52–3.95, P < 0.001) after adjusting for molecular subtype and adjuvant therapy. The three-tier risk stratification identified distinct prognostic groups: low risk (0 points, n = 198, 48.1%): 3-year RFS 91.2%; intermediate risk (1–2 points, n = 163, 39.6%): 79.4%; high risk (3–5 points, n = 51, 12.4%): 52.8% (P < 0.001). In propensity score-matched analysis, EBRT significantly improved 3-year RFS in deep CSI patients (78.6% vs. 48.2%, P = 0.012; HR 0.42, 95% CI 0.20–0.88), with particular benefit for locoregional control (89.3% vs. 62.5%, P = 0.008).

The prognostic impact of deep CSI varied by molecular subtype: no significant effect in polymerase epsilon (POLE)-mutated, mismatch repair deficient (MMRd) tumors, but identified high-risk subsets within no specific molecular profile (NSMP) tumors.</p>Conclusions<p>Deep CSI provides critical prognostic information in endometrioid endometrial cancer. Integration of CSI depth with molecular classification enables actionable risk stratification and identifies patients who benefit from EBRT.</p>