Results indicate radiologic findings are better survival predictors than pathologic vessel invasion.
Features picked up by MRI can help predict outcomes for some patients with colorectal liver metastasis, and, potentially, help direct treatment plans, new research has revealed.
MRI studies enhanced with gadoxetic acid (Gd-EOB-DTPA) is already considered superior to CT when it comes to detecting colorectal liver metastases (CRLMs) smaller than 10 mm, but in a study published on Oct. 6 in Radiology, a team of investigators from the University of Tokyo shared several identified radiologic features that can predict long-term prognosis.
“Bile duct dilatation peripheral to a colorectal liver metastasis indicated poor long-term prognosis in patients who had undergone curative surgical resection without neoadjuvant chemotherapy,” said the team led by Yudai Nakai, M.D., Ph.D., from the department of radiology at the University of Tokyo. “A combination of early enhancement, reduced gadoxetic acid uptake, and bile duct dilatation peripheral to the tumor was predictive of poor overall survival.”
To make this determination, the team conducted a retrospective study, analyzing records from patients who underwent gadoxetic acid-enhanced MRI before curative surgery for CRLM without neoadjuvant surgery. They used a 1.5T and 3T MRI scanners to capture contrast-enhanced hepatobiliary phase images, as well as axial T1-weighted, heavily T2-weighted, and diffusion-weighted images. Studies were conducted between July 2008 and June 2015.
In a patient population of 106 individuals – 68 men and 38 women – Nakai’s team identified 148 CRLMs. Of the group, 21 patients (20 percent) had extrahepatic lesions – 12 in the lungs, 4 in the distant lymph nodes, 3 in the adrenal gland, 2 of local recurrence, 2 of peritoneal dissemination, and 1 in the ovary. All lesions were radically resected before, during, or after hepatectomy. Investigators followed the patients for an average of 60 months during which 40 patients (38 percent) died and 68 (64 percent) developed a local or metastatic tumor recurrence.
Based upon their analysis, the researchers discovered that bile duct dilatation peripheral to the tumor was associated with pathological portal vein invasion with a sensitivity and specificity of 24 percent and 91 percent, respectively, and bile duct invasion with sensitivity and specificity of 42 percent and 90 percent, respectively.
In addition, the team said, in the context of recurrence-free survival, there were four factors that emerged as independent predictors of an unfavorable prognosis for the patient – positive surgical margin, the presence of CRLM with bile duct dilatation in the periphery, two or more CRLMs at MRI, and a history of extrahepatic disease.
The independent predictors of a negative prognosis were different for overall survival, though. Here, researchers identified five other factors – receipt of adjuvant chemotherapy, CRLM with bile duct dilatation in the periphery, at least 65 years old, positive surgical margin, and the presence of two or more CRLMs. And, overall survival was worse, they said, among patients with CLRM with bile duct dilatation in the periphery or those who were CRLM positive for one or more of the three findings peripheral to the tumor.
Ultimately, Nakai’s team said, the radiologic findings did a better job of predicting survival than pathologic vessel invasion. Not only did images provide greater detail, including specifics about lymphatic invasion or inflammation, but they also excluded microscopic findings that had no impact on prognosis.
In an accompanying editorial, Mustafa R. Bashir, M.D., associate professor of radiology and director of MRI at Duke University Health System, said these findings could play a role in more effectively triaging patients.
“These findings raise the possibility of stratifying patients based on more nuanced imaging findings than the size, number, and location of CRLMs,” Bashir said. “Their work identified imaging findings that imply local invasiveness of the tumor mass, a factor associated with poorer outcomes after resection.”
While questions remain about whether patients with adverse imaging features still benefited from curative-intent resection and what would be the surgical treatment of choice in the treatment of limited metastatic disease, he said, these findings offer an opportunity for cure in this patient population.
“Nakai and colleagues have proposed specific MRI-based features that may help predict oncologic outcomes after resection,” he said. “This report supports the concept of using the wealth of data available at imaging to stratify patients according to risk with the potential to help oncologists and surgeons offer optimal treatment.”
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