Optimal timing of computed tomography for assessing lymph nodes after neoadjuvant chemoradiotherapy for rectal cancer

Abstract

Background: This study assessed the op mal ming of computed tomography for detec on of metasta c disease in locoregional lymph nodes in pa ents with rectal cancer who have undergone chemoradiotherapy. Materials and Methods: This observa onal retrospec ve study was performed in a single ins tu on. All pa ents with locally advanced rectal cancer treated with chemoradiotherapy, followed by a total mesorectum excision from January 1, 2003 to December 31, 2012, were included. Lymph node metastases evident on preopera ve computed tomography were compared with postopera ve pathologic lymph node status. Results: The study popula on consisted of 108 pa ents: Group A (nodal nega ve on preopera ve computed tomography, n = 52) and Group B (nodal posi ve on preopera ve computed tomography, n = 56). Analysis of the computed tomography scans in Group A revealed a high ability (98.07%) to predict nega ve lymph nodes, compared to 58.92% for predic ng posi ve lymph nodes in Group B. Conclusion: The results of this study suggest that the op mal ming of computed tomography for assessing lymph nodes a0er neoadjuvant chemoradiotherapy for rectal cancer is a0er 6 weeks; this ming might be key for predic on of complete clinical responses.