Clinical relevance of morphologic MRI criteria for the assessment of lymph nodes in patients with rectal cancer

Abstract

In clinical routine, lymph node assessment in patients with rectal cancer through MRI tends to overstage malignant lymphadenopathy. A ≤5-mm cutoff value for the short-axis lymph node diameter of benign nodes is able to improve the accuracy and has potential to lower the risk of overstaging.

Value of MRI morphologic features with pT1‐2 rectal cancer in determining lymph node metastasis

“…Our result was close to that of a previous study attempting at distinguishing malignant and benign LNs . Although there is still quite a lot of controversy about the size of the LN in differentiating metastatic LNs from nonmetastatic ones due to the overlap between them, the diameter of the largest LNs may still be helpful in determining LNM, especially in T1‐2 stage rectal cancer.…”

Contrast‑enhanced CT imaging for the assessment of lymph node status in patients with colorectal cancer

“…Previous studies have assessed the value of MRI and positron emission tomography in predicting the metastatic status of LNs (10,36,37). Doyon et al (38) and Gagliardi et al (39) demonstrated that a threshold value of >5 mm could be used to identify LN+. Margin characteristics and the signal intensity of LNs were also significant variables for the assessment of LN metastatic status in patients with colon cancer (24).…”

The Current Status of Nodal Staging in Rectal Cancer

“…While radiologists regard enlarged LN as an indicator of malignancy, in contrast, in histopathological studies, the presence of numerous large LN has actually been recognised as a good prognostic marker in a number of studies, possibly as a result of an appropriate immune response to the tumour which confers a survival advantage [17][18][19]. Morphological predictors of nodal involvement, namely mixed signal intensity and irregular borders, have been shown to have greater accuracy than LN size (sensitivity 85% and specificity 97% [16] vs sensitivity 67% and specificity 83% if a 5-mm cut-off is used [20]). However, it is likely that this definition included TD in the past which would also have had irregular borders and were likely to have been classified as LNM on pathology.…”

“…Generally, MRI sensitivity and specificity for LNM is only moderate and MRI has a tendency to overstage within the nodal category [20][21][22][23] compared with pathology. A recent large retrospective study showed a sensitivity of only 38%, a specificity of 87% and a positive predictive value of 56% for the diagnosis of LNM on MRI compared with pathology, which the authors compared with flipping a coin [24•].…”