[Magnetic resonance and extramural vascular invasion in patients with rectal cancer and liver metastases]. / Resonancia magnética e invasión vascular extramural en pacientes con cáncer rectal y metástasis hepaticas.

BACKGROUND: Extramural vascular invasion (EMVI) in patients with rectal cancer (RC) is associated with more locally advanced tumors, and independently predicts local and distant recurrence and poor overall survival. OBJETIVE: To determine the association between EMVI and synchronous liver metastases in patients with RC. METHODS: We performed a retrospective cohort study including patients with cancer of middle and lower rectum, which were evaluated with magnetic resonance (MRI) for initial staging in the period from January 2011 to January 2012 inclusive. All patients were evaluated with MRI for EMVI and were followed for a year to detect synchronous liver metastases by imaging methods (January 2012 to January 2013 inclusive). Multivariate analysis was performed by logistic regression. RESULTS: We included 68 patients. Twenty had liver metastases during the observation period (29.41%), of whom 15 had signs of MRI EMVI (75%). The incidence of synchronous liver metastases had a marginally significant association with the presence of EMVI (RR 3.35, 95% CI: 1.0001-11.2187, P = 0.050). CONCLUSION: The presence of MRI EVMI is a poor prognostic predictor factor of development of synchronous liver metastases in patients with RC.

[Diffusion-weighted MR imaging in patients with rectal cancer: our initial experience]. / Resonancia magnética con difusión en pacientes con cáncer de recto: experiencia inicial.

BACKGROUND: Pre-surgical characterization of post-neoadjuvant residual tumor response in patients with rectal cancer by means of an imaging technique could be useful in order to determine the therapeutic strategy or observation. OBJECTIVE: To evaluate the role of the diffusion magnetic resonance imaging (DWMR) in the determination of residual primary tumor (RPT) or post-neoadjuvant complete pathologic response (CPR) in patients with rectal cancer (RC). MATERIAL AND METHODS: Eighteen patients (13 males and 5 females) operated between June 2009 and September 2010 were included. The inclusion criteria were medial and low rectal tumors, with T3-T4- positive lymph nodes, defined by physical examination (rectal tact) and studies by imaging techniques (DWMR and multidetector computed tomography (MDCT). All patients received neoadjuvant treatment before surgery. Patients were later reevaluated with DWMR using visual and quantitative scales in order to measure the apparent diffusion coefficient (ADC). The results were compared to pathological anatomy (PA) as gold standard. DWMR was performed on a Siemens Avanto 1.5 T RESULTS: In the PA 15 of 18 patients presented RPT, whereas 3 patients showed a CPR. When the DWMR was used with the visual scale, RPT was detected in 14 of 15 patients, whereas all patients with RPT were detected using the quantitative scale. In those cases with complete CPR by PA, the DWMR and visual scale detected 2 of 3 patients whereas the quantitative scale in ADC detected all three cases. CONCLUSION: DWMR proved to be a useful method in the determination of post-neoadjuvant RPT and CPR in patients with rectal cancer, especially when the quantitative assessment of the ADC was performed, resulting in an improvement of the results obtained by means of the qualitative visual analysis.