Computed Tomography of Lymph Node Metastasis Before and After Radiation Therapy: Correlations With Residual Tumour.

Background: Computed tomography (CT) performed after radiation therapy (RT) is used to detect residual lymph node (LN) metastasis. Here, we investigated which LN parameters on pre- and post-RT CT images correlated with residual tumour in patients with head and neck cancer.

Patients And Methods: We enrolled 23 patients who received RT. A total of 50 LNs were evaluated. Correlations between quantitative and qualitative findings and residual tumours were evaluated.

Results: The median patient age was 61 years. Thirty-one LNs were histologically confirmed to contain residual tumour. LNs with residual tumour had significantly longer short and long axes on post-RT CT images. A new finding of obscured margins after RT were significantly associated with the presence of residual tumour by univariate and multivariate analyses.

Conclusion: Comparison of qualitative, LN parameters on pre- and post-RT CT images may improve the detection of residual tumour in patients with suspected residual or recurrent LN metastasis.