Which factors predict the effectiveness of adjuvant treatment in patients with non-high-risk early-stage cervical cancer? Ancillary analysis of KGOG-1028

Objective: To identify predictive factors for the effectiveness of adjuvant therapy (AT) in patients with non-high-risk early-stage cervical cancer. Methods: A retrospective cohort study was conducted using data from the Korean Gynecologic Oncology Group-1028, which included 1109 low-risk and 360 intermediate-risk patients diagnosed with 2018 FIGO stage IB1-IIA cervical cancer from 2000 to 2008. Disease-free survival (DFS) according to AT was evaluated in restricted patients with certain prognostic factors, such as lymphovascular space invasion (LVSI), depth of invasion (DI) of 1/3, tumor size >4 cm, or nonsquamous cell carcinoma (non-SCC). In addition to the prognostic factor of interest, clinicopathologic factors were balanced between the AT-naïve and AT groups using the inverse probability of treatment weighting. Results: AT was administered to 281 (25.2 %) low-risk patients and 261 (72.5 %) intermediate-risk patients. Positive LVSI, DI of deep 1/3, tumor size >4 cm, and adenocarcinoma histology were significantly prognostic when tested in the AT-naïve group. AT was effective in prolonging DFS in patients with positive LVSI (hazard ratio [HR] = 0.37; 95 % CI, 0.23–0.60), DI of deep 1/3 (HR = 0.29; 95 % CI, 0.17–0.49), and tumor size >4 cm (HR = 0.28; 95 % CI, 0.11–0.70). However, AT was not effective in patients with non-SCC histology (HR = 0.69; 95 % CI, 0.41–1.16). Conclusions: Patients with non-high-risk early-stage cervical cancer with any of the following conditions, including positive LVSI, DI of deep 1/3, and tumor size >4 cm, can benefit from AT but not those with non-SCC histology.