Clinico-pathological characteristics of patients with stage IB1–IB2 (FIGO 2018) uterine cervical cancer: a nationwide study in Japan

Objective: The aim of this retrospective analysis is to reveal clinicopathological findings and clinical outcome of patients with stage IB1/IB2 (FIGO 2018) uterine cervical cancer. Methods: Based on the database of the Japanese Gynecologic Oncology Group, 2194 patients with stage IB1/IB2 (FIGO 2018), who underwent radical hysterectomy between 1/1/2004–12/31/2008, were identified as eligible for this retrospective study. Results: Patients with squamous cell carcinoma had significantly frequent lympho-vascular space invasion than those with non-squamous cell carcinoma in both stage IB1 and IB2 (stage IB1; 29.1% vs. 17.1%, p < 0.0001, stage IB2; 50.5% vs. 39.7%, p = 0.0009). Among 1262 patients with stage IB1, 61.2% (772/1262) were low-risk group, 29.4% (371/1262) were intermediate-risk group (single risk: 23.3%, double risks: 6.1%). Of 932 patients with stage IB2, 32.1% (299/932) were low-risk group, 59.1% (551/932) were intermediate-risk group (single intermediate-risk: 31.0%, double intermediate-risk: 28.1%). Disease-free survival rate and overall survival rate of stage IB1 patients were significantly better than those with stage IB2 (5-year DFS; 94.7% vs. 88.6%, p < 0.001, 5-yrs OS; 98.5% vs. 95.1%, p < 0.001). Stage IB1 Patients with double intermediate-risk showed significantly worse survival than those with single intermediate-risk (5-yrs DFS: 96.1% vs. 84.6%, p < 0.001, 5-yrs OS: 98.9% vs. 93.0%, p = 0.029). Multivariate analysis revealed that double intermediate-risk was the independent prognostic factor in stage IB1, but non-squamous cell carcinoma and intermediate-risk in stage IB2. Conclusion: Non-squamous cell carcinoma and intermediate-risk decreased survival in patients with stage IB2, whereas double intermediate-risk was a negative impact on survival in stage IB1.