Yaena Kim MD, Presenter: Nothing to Disclose

Joo Hee Kim, Abstract Co-Author: Nothing to Disclose

Jae-Joon Chung MD, Abstract Co-Author: Nothing to Disclose

Jeong-Sik Yu MD, Abstract Co-Author: Nothing to Disclose

Jhii Hyun Ahn MD, Abstract Co-Author: Nothing to Disclose

Eun-Suk Cho, Abstract Co-Author: Nothing to Disclose

The lymphovascular invasion (LVI) is one of the poor prognostic factors in rectal cancer. The aim of this study was to evaluate the LVI using pelvic MR in patients with rectal cancer preoperatively and a correlation with distant metastasis rates.

A total of 113 patients with rectal cancer underwent high-resolution pelvic MRI for preoperative evaluation. An experienced MR radiologist prospectively assessed all MR images. If the mesorectal perivascular infiltrative signal was visible on pelvic MR, the possibility of the presence LVI was recorded. Distant metastatic lesions were also recorded at that time of initial diagnostic work-up. Among them, surgical resection of rectal cancer was performed in 95 patients. They were compared with pathologic results. Missed or newly developed metastases and recurrence were assessed in 2 year follow-up periods.

Among 95 patient, 22 patients (23.2%) had LVI. For prediction of LVI in rectal cancer, MR had the sensitivity of 68.2%, specificity of 93.2%, positive predictive value of 75%, and negative predictive value of 90.1%. MR true positive was seen in 15 patients and among them, 11 had distant metastases (7 at initial diagnosis, 4 during follow-up period). Although MR was false positive (n=5, perinodal soft tissue extension in 2, radiation therapy in 2), but 3 of patients had distant metastases. While distant metastases are seen at that time of diagnosis in patients without LVI (2.7%)/with LVI (36.4%), new metastatic lesions are seen during follow-up in patients without LVI (15.1%)/with LVI (18.2%).

On high-resolution pelvic MR, mesorectal perivascular infiltration by nodes is a specific sign of LVI in rectal cancer and a correlation of high rates of distant metastasis.

Further vigorous preoperative work-up study are recommended for evaluation of distant metastasis in patients with suspicious LVI at preoperative MR for rectal cancer.

Kim, Y, Kim, J, Chung, J, Yu, J, Ahn, J, Cho, E, Preoperative Evaluation of Lymphovascular Invasion on Pelvic MR in Patient with Rectal Cancer: Two-Year Follow-up.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11010213.html