Local recurrence of rectal cancer, the main factor in treatment failure, typically occurs during the first 12 to 24 months of follow-up. Researchers from South Korea found a correlation between preoperative MR images and local recurrence.
"If we can identify high-risk patients before surgery, the treatment planning can be more tailored to reduce local recurrence," said Dr. Young Taik Oh.
For this study, Oh and colleagues selected 17 rectal cancer patients with local recurrence and 54 patients without recurrence who were followed for at least two years. All patients underwent preoperative rectal MR in a 1.5T scanner with a phased-array coil and received a curative operation.
Three readers independently reviewed the MR findings, which included perirectal fat involvement and involvement pattern, lymph node involvement and spiculated lymph node, abutting of mesorectal fascia, perirectal organ invasion, gross perivascular encasement by tumor, and mucin pool within the mass.
Significant findings in the locally recurred group were perivascular encasement by tumor and spiculated lymph node. These findings may indicate high probability for local recurrence, according to Oh.
In another study, preoperative MR received good marks for detecting hepatic metastasis in rectal cancer patients.
Dr. Joon Seok Lim and colleagues from South Korea selected 149 patients according to the following criteria:
? received curative resection for rectal cancer
? no evidence of hepatic metastasis on preoperative MR
? serial follow-up of more than 18 months with CT
Researchers assumed that newly developing hepatic metastases within 18 months were occult metastases not detected on the preoperative MR.
Hepatic metastasis was detected in 11 patients within the 18 months and in two patients after 18 months.
Lim concluded that preoperative MR is sensitive for detection of metastasis in rectal cancer patients scheduled for curative surgery.