Rationality of FIGO 2018 IIIC cervical cancer according to local tumor and pelvic lymph node metastatic extent-a cohort study.

Purpose: There is still controversy for FIGO 2018 stage IIIC. In order to better manage patients with stage IIIC. This study explored the prognostic performance of Stage IIIC patients according to the 2018 FIGO staging system.

Methods: Cervical cancer patients who underwent radical surgery or chemo-radiotherapy at our institute between June 2011 and June 2021 were retrospectively enrolled. Patients before year 2018 were re-staged according to the 2018 FIGO staging principle. Survival outcome was analyzed by Kaplan-Meier curves and compared using Log-rank method. The best cut-off values for the number of positive lymph nodes and the positive lymph node ratio (LNR) were obtained using X-tile software V3.6.1. The Cox proportional hazard regression model was used for multi-variable analysis.

Results: A total of 2553 cervical cancer patients were enrolled initially. Finally, 443 patients classified as 2018 FIGO stage III were included in the survival analysis.The 5-year disease-free survival (DFS) and 5-year overall survival (OS) of patients with stage IIIC2 were significantly poor than stage IIIA, IIIB and IIIC1, while IIIC1 patients had similar prognosis to IIIA/IIIB. For stage IIIC1 patients (n = 233), multivariate analysis showed that tumor size > 4 cm (DFS: HR 2.472, P < 0.001; OS: HR 2.368, P = 0.002) and poorly-differentiated histology (DFS: HR 2.158, P = 0.002; OS: HR 2.410, P = 0.002) were independent prognostic factors for reduced DFS and OS. In a subgroup analysis of IIIC1p women, tumor size > 4 cm (DFS: HR 2.658, P = 0.023; OS: HR 2.785, P = 0.039) and the number of positive pelvic lymph nodes(pLN) > 3 (DFS: HR 4.829, P < 0.001; OS: HR 5.614, P < 0.001) were found to be independent risk factors for reduced DFS and OS. Combining the local tumor size (TS) and pLN, patients with TS ≤ 4 cm + pLN ≤ 3 revealed significantly better 5-year DFS (89.2%) and 5-year OS (94.9%) than those with TS ≤ 4 cm + pLN > 3 and TS > 4 cm (P < 0.001). Moreover, stage IIIC1p patients with TS ≤ 4 cm + pLN ≤ 3 showed better DFS (P = 0.002) and OS (P = 0.001) than women with stage IIIA and IIIB.

Conclusion: The survival outcomes for stage IIIC1 had similar prognosis for stage IIIA or IIIB in the current study. Patients with stage IIIC1p showed variable prognoses dependent on local tumor size and the extent of pelvic lymph node metastases. Therefore, the existing staging criteria might be further improved to provide better guidance for individualized treatment.