Post-CCRT pelvic lymph node size and pathological nodal involvement in cervical cancer.

BACKGROUND: Lymph node metastasis is an important prognostic factor in cervical cancer, but assessment of nodal response after concurrent chemoradiotherapy (CCRT) remains difficult. This study evaluated the diagnostic value of post-CCRT lymph node size for predicting pathological nodal involvement using a cohort treated with CCRT followed by planned surgery. METHODS: This retrospective cohort study included 57 patients with cervical cancer who underwent CCRT followed by surgery including pelvic lymphadenectomy. The short- and long-axis diameters of the largest pelvic lymph node were measured on computed tomography before and after CCRT. Histopathological findings of resected lymph nodes were used as the reference standard. Receiver operating characteristic (ROC) analysis was performed to assess diagnostic performance. RESULTS: Pathological nodal metastasis was identified in 17 of 57 patients (29.8%). Post-CCRT lymph node diameters were significantly larger in the ypN1 group than in the ypN0 group. The short-axis diameter showed better diagnostic performance than the long-axis diameter, with an area under the curve of 0.859 (95% CI, 0.752-0.966) versus 0.802 (95% CI, 0.676-0.927). Among integer cutoff values, the short-axis diameter showed the highest Youden index at 5 mm and the highest F1 score at 7 mm. At a 7-mm cutoff, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 58.8%, 90.0%, 71.4%, 83.7%, and 80.7%, respectively. CONCLUSION: Post-CCRT pelvic lymph node size, especially the short-axis diameter, may be useful for estimating residual pathological nodal disease in cervical cancer.