Session 2: Synchronous metastatic disease-liver first or primary first? The oncologist decides

The diagnostic performance of a simulated "short" gadoxetic acid-enhanced MRI protocol is similar to that of a conventional protocol for the detection of colorectal liver metastases

OBJECTIVES

To compare the performance of standard and simulated short gadoxetic acid-enhanced MRI protocols for the detection of colorectal liver metastases (CRLM).

METHODS

From 2008 to 2017, 67 patients (44 men (66%); mean age 65 ± 11 years old) who underwent gadoxetic acid-enhanced MRI during the initial work-up for colorectal cancer were included. Exams were independently reviewed by two readers blinded to clinical data in two reading sessions: (1) all acquired sequences (standard "long" protocol) and (2) only T2-weighted, diffusion-weighted, and hepatobiliary phase images (simulated "short" protocol). Readers characterized detected lesions using a 5-point scale (1-certainly benign to 5-certainly malignant). A lesion was considered a CRLM when the score was ≥ 3. The reference standard was histopathology or 12-month imaging follow-up. Chi-square, Student's t, and McNemar tests were used for comparisons.

RESULTS

A total of 486 lesions including 331 metastases (68%) were analyzed. The metastasis detection rate was 86.1% (95% CI 82-89.4)-86.7% (82.6-90) and 85.8% (81.6-89.2)-87% (82.9-90.2) with the short and long protocols, respectively (p > 0.99). Among detected lesions, 92.1% (89.1-94.4)-94.8% (92.2-96.6) and 84.6% (80.8-87.7)-88.8% (85.4-91.5) were correctly classified with the short and long protocols, respectively (p = 0.13 and p = 0.10). The results remained unchanged when lesions scored ≥ 4 were considered as CRLM.

CONCLUSION

The diagnostic performance of a simulated short gadoxetic enhanced-MR protocol including T2-weighted, diffusion-weighted, and hepatobiliary phase appears similar to that of a standard long protocol including dynamic phase images. Since this protocol shortens the duration of MR examination, it could facilitate the evaluation of patients with colorectal liver metastases.

KEY POINTS

• The detection rate of colorectal metastases with a simulated, short, MRI protocol was similar to that of a standard protocol. • The performance of both protocols for the differentiation of metastases and benign lesions appears to be similar. • A short MR imaging protocol could facilitate the evaluation of patients with colorectal liver metastases.

Downregulated IGFBP7 facilitates liver metastasis by modulating epithelial‑mesenchymal transition in colon cancer

Distant metastasis is a major cause of cancer-associated mortality in patients with colon cancer. Insulin-like growth factor binding protein 7 (IGFBP7) has been identified as a crucial inhibitor of human cancer. However, the role of IGFBP7 in the pathogenesis of metastatic colon cancer has not been investigated. In the present study, the expression of IGFBP7 in 81 pairs of colon cancer tissues and adjacent normal tissues were investigated using immunohistochemistry. Furthermore, 24 pairs of primary colon cancer and matched liver metastasis tissues were analyzed. LοVο cells with IGFBP7-knockdown and HT-29 cells with IGFBP7-overexpression were employed. The expression levels of E-cadherin, N-cadherin and Vimentin were quantified and compared. Significant alterations in the expression of IGFBP7 between late stage (III + IV) colon cancer and adjacent normal colonic mucosa were observed. (P=0.031). The association between IGFBP7 and epithelial-mesenchymal transition (EMT) markers were validated in primary colon cancer and matched liver metastasis tissues. The invasive front of liver metastatic colon tissues revealed reduced IGFBP7 expression. Additionally, knockdown of IGFBP7 in LοVο cells resulted in decreased E-cadherin, and increased N-cadherin and Vimentin expression compared with the control group. Overexpression of IGFBP7 in HT-29 cells induced an upregulation of E-cadherin; however, the N-cadherin and Vimentin levels were decreased. In conclusion, the results of the present study suggested that IGFBP7 may prevent colon cancer metastasis by inhibiting EMT, and serves as a potential diagnostic marker and therapeutic target for patients with colon cancer.