MRI for detection of extramural vascular invasion in rectal cancer.

OBJECTIVE: Extramural vascular invasion is a pathologic feature predictive of distant relapse and poor survival among patients with colorectal cancer. This article illustrates the use of high-spatial-resolution MRI to identify extramural vascular invasion. CONCLUSION: Objective MRI features that correlate with histopathologic findings can be identified and used to evaluate extramural vascular invasion on preoperative images. The MRI extramural vascular invasion score provides additional staging information, which is important when selective neoadjuvant therapy is being considered.

The Relationship Between MR Demonstration of Extramural Venous Invasion and Nodal Disease in Rectal Cancer.

PURPOSE: To investigate the relationship between extramural venous invasion (EMVI) detected at T2-weighted MRI and nodal disease rectal cancer compared with histopathology. MATERIALS AND METHODS: The MR imaging of 79 consecutive patients with rectal cancer who underwent primary rectal surgery without neoadjuvant treatment were reviewed. MR images were scored by an expert radiologist for the presence and degree of EMVI using a five point scale blinded to pathological findings. Receiver operating characteristic curve analyses were performed to determine the sensitivity and specificity of MRI scoring in predicting EMVI and nodal disease at histopathology. RESULTS: Compared with histology, an MR score of >2 was found to have 100% sensitivity (95% CI: 77%-100%) and 89% specificity (95% CI: 79%-96%) in identifying EMVI involving veins >3 mm in diameter. An EMVI score of >2 was had a sensitivity of 56% (95% CI: 30%-80%) and specificity of 81% (95% CI: 69%-90%) for identifying patients with stage N2 disease. CONCLUSIONS: EMVI score of >2 on T2-weighted MR imaging has a high sensitivity and specificity for histopathologically proven extramural venous invasion involving venules ≥3 mm in diameter. However, EMVI scores have only moderate sensitivity in the predicting nodal involvement.

Molecular pharmacology of cancer therapy in human colorectal cancer by gene expression profiling.

Global gene expression profiling has potential for elucidating the complex cellular effects and mechanisms of action of novel targeted anticancer agents or existing chemotherapeutics for which the precise molecular mechanism of action may be unclear. In this study, decreased expression of genes required for RNA and protein synthesis, and for metabolism were detected in rectal cancer biopsies taken from patients during a 5-fluorouracil infusion. Our observations demonstrate that this approach is feasible and can detect responses that may have otherwise been missed by conventional methods. The results suggested new mechanism-based combination treatments for colorectal cancer and demonstrated that expression profiling could provide valuable information on the molecular pharmacology of established and novel drugs.

Use of plasma MMP-2 and MMP-9 levels as a surrogate for tumour expression in colorectal cancer patients.

Matrix metalloproteinases, and notably the gelatinases MMP-2 and MMP-9, have important roles in tumour invasion, metastasis and angiogenesis. Our study investigates the distribution of MMP-2 and MMP-9 in colorectal cancer, the correlation with plasma levels, changes following surgical resection and whether plasma levels reflect clinical staging and disease course. MMP-2 and MMP-9 expression in 48 colorectal tumours and 13 adenomatous polyps was analysed by RT-PCR, immunohistochemistry, and quantified by ELISA of tumour lysates. Concentrations of MMP-2 and MMP-9 in plasma samples from these patients and 36 other patients who underwent curative resections were measured by ELISA prior to and 6-12 months after surgery. MMP-2 expression was significantly increased in colorectal cancer tissues compared to matched normal colon as measured by ELISA. Active MMP-2 was localised by immunohistochemistry to regions where tumour cells invaded the muscularis with little staining in more superficial areas. Plasma MMP-2 levels were also significantly elevated in patients with colorectal cancer, with significant reductions following curative resections at all stages. Similarly, MMP-9 expression was significantly increased in colorectal cancer tissues, predominantly in the tumour stroma. Plasma levels of MMP-9 were significantly elevated at all stages in colorectal cancer patients and a significant reduction was seen following curative resections. With both MMP-2 and MMP-9, the strongest correlation with clinical staging in colorectal cancer was represented by the total plasma concentration of the enzymes, both falling to within the normal range following curative surgery. Plasma levels of these enzymes may therefore have potential as a noninvasive indicator of invasion or metastasis in colorectal cancer or as a marker of disease status during follow-up.