Background: Adjuvant therapy is usually considered for surgically treated patients with uterine cervical cancer harboring intermediate risk (IR) factors such as large tumor diameter, stromal invasion to the outer half, and lymphovascular space invasion (LVSI). However, the indications and types of adjuvant therapy for the IR group remain controversial. This study aimed to analyze the differences in patient outcomes in the IR group to provide novel insights for tailoring adjuvant therapy. Methods: Data from 6192 patients with cervical cancer who underwent radical hysterectomy at 116 institutions belonging to the Japanese Gynecologic Oncology Group were reviewed. Results: In total, 1688 patients were classified into the IR group, of whom 37.3% did not receive adjuvant therapy. Conversely, approximately equal proportions of the remaining patients received adjuvant radiotherapy, concurrent chemoradiotherapy, and chemotherapy. Patients with all three risk factors showed worse overall survival than those with one or two risk factors. In addition to LVSI, non-squamous cell carcinoma histology, and vaginal invasion were identified as independent risk factors for both recurrence and mortality in multivariate analyses. Tumor diameter greater than 40 mm and surgical center volume were identified as independent risk factors for recurrence. Stromal invasion to the outer half and ovarian metastasis were identified as independent risk factors for mortality. Conclusions: This study revealed the significant differences in prognosis in the IR group. The indications for adjuvant therapy should be further studied, focusing on conventional risk factors and other pathological findings.
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