Extramural venous invasion (EMVI) can be reliably evaluated with MRI in patients with locally advanced rectal cancer treated with neoadjuvant chemotherapy–radiation therapy followed by surgery, according to new research published in Radiology.
The authors, led by Ying-Shi Sun, MD, of the Peking University Cancer Hospital and Institute in Beijing, noted the presence of EMVI was associated with an increased risk of local and distant tumor recurrence in patients with locally advanced rectal cancer treated with neoadjuvant chemotherapy–radiation therapy.
“To our knowledge, there have been no reports on the prognostic impact of baseline determination of EMVI by using MRI in patients with rectal cancer,” Sun and colleagues wrote. “Although some studies recommended that MRI be used to determine the presence or absence of EMVI, it is still unknown how risk stratification of MRI-defined EMVI can be used to identify patients with different survival outcomes.”
To better understand the relationship between MRI-defined EMVI and patient outcomes, the researchers conducted a retrospective study that included more than 500 patients with locally advanced rectal cancer.
The researchers obtained baseline and posttherapy MRI and follow up data for all patients. After training by using 328 cases with pathologic evaluation in EMVI after therapy, the researchers evaluated baseline MRI for EMVI status with tumor size and characteristics, nodal status and invasion of the mesorectal fascia.
At baseline, the researchers found 50 percent of their study cohort exhibited MRI-defined EMVI. They found that EMVI (hazard ratio 0.3) and mesorectal fascial invasion (HR 0.6), at baseline MRI, were predictors of metastasis-free survival. Additionally, EMVI (HR 0.5) and mesorectal fascial invasion (HR 0.5) at baseline were predictors of overall survival.
The researchers found that EMVI was the only factor associated with local relapse-free survival (HR 0.3).
“This study has shown that baseline MRI-defined EMVI is an independent risk factor for local and distant recurrence as well as overall survival, serving as important evidence of baseline risk stratification,” the researchers wrote. “The location of the MRI-defined EMVI was shown as the only independent factor for divergent recurrence in patients with positive findings for baseline MRI-defined EMVI.”
The researchers noted their results showed that in patients with positive findings for baseline MRI-defined EMVI, the change in MRI-defined EMVI status from positive to negative did not increase odds for survival or decrease chances of recurrence, which contradicts previous research. Change in EMVI status from positive to negative, the researchers noted, can prevent more tumor cells from flowing into the circulation system. It does nothing, however, for the tumor cells already in circulation.
“This study demonstrates that baseline MRI-defined EMVI status can be reliably evaluated and can potentially serve as an independent prognostic factor for recurrence and overall survival in patients with locally advanced rectal cancer,” the researchers concluded. “We have provided important evidence that baseline MRI-defined EMVI status could be considered for managing risk stratification in baseline locally advanced rectal cancer.”
As a senior news writer for TriMed, Subrata covers cardiology, clinical innovation and healthcare business. She has a master’s degree in communication management and 12 years of experience in journalism and public relations.