Risk Factor Analysis and Prediction of Para-Aortic Lymph Node Metastases in Locally Advanced Cervical Cancer

The indications of prophylactic extended-field radiotherapy (EFRT) remain uncertain. This study aims to identify the risk factors for para-aortic lymph node (PALN) metastases in locally advanced cervical cancer (LACC) and determine which part of patients may benefit from prophylactic EFRT.

Between January 2015 and July 2023, a single-center retrospective analysis was performed on patients with stages IB3 and IIA2-IVA cervical cancer. Lymph node involvement was assessed using positron emission tomography/computed tomography (PET/CT). Risk factors were evaluated by logistic regression. A prediction nomogram model was developed and validated.

Among 329 patients, 64 (19.5%) had PALN metastases. Univariate analysis indicated that tumor size > 5.3 cm, tumor maximum standardized uptake value (SUVmax) > 9.8, bilateral pelvic lymph node (PLN) metastases, the number of positive PLNs ≥ 3, and T3-T4 stages were related to PALN metastases. After multivariate logistic analysis, it was found that tumor size > 5.3 cm (odds ratio [OR] = 3.129, 95% confidence interval [CI] = 1.536-6.374, p = 0.002), and the number of positive PLNs ≥ 3 (OR = 11.260, 95% CI = 3.506-36.158, p < 0.001) were independent risk factors. The C-index of the nomogram was 0.886 (95% CI = 0.844-0.927). The calibration plot showed that the nomogram was well-fitted. Decision curve analysis (DCA) exhibited excellent clinical utility.

Tumor size > 5.3 cm and the number of positive PLNs ≥ 3 are independent risk factors of PALN metastases. The nomogram shows pretty good accuracy, which may provide a valuable reference for guiding patients who are very likely to develop PALN metastases to receive prophylactic EFRT.