Extent of remnant liver ischemia may predict survival after colorectal liver metastases

Last Updated: 2017-09-07

By Marilynn Larkin

NEW YORK (Reuters Health) - A greater degree of remnant liver ischemia (RLI) after hepatic resection may be a significant predictor of worse recurrence-free and cancer-specific survival in patients who undergo curative resection of colorectal metastases (CLMs), researchers say.

"RLI is a result of the surgeon compromising the blood supply to parts of the liver that are not being resected with the metastases," Dr. Claudius Conrad of University of Texas MD Anderson Cancer Center in Houston explained in an email to Reuters Health. "(We) found that a higher degree of RLI on postoperative CT scans associated with worse cancer-specific survival after resection of CLMs."

The finding could be practice-changing, according to Dr. Conrad. "We never thought it mattered much how we get the metastases out as long as we get them out," he said. "For the first time, we show that leaving non-perfused liver behind (a technical consideration) impacts survival (a cancer biology consideration)."

"Also, prognosis is mainly thought to be determined by how aggressive the cancer is, which is not something we can change as doctors," he added. "(Now) we show that with more precise surgery, we can impact prognosis."

Dr. Conrad and colleagues investigated the prognostic value of RLI in 202 patients (median age, 56;, 42% female) who underwent curative resection of CLMs between 2008 and 2014, and had enhanced CT images available within 30 days after surgery.

RLI was defined as "reduced or absent contrast enhancement during the portal phase" of CT. Postoperative RLI was classified as grade 0 (none), 1 (marginal), 2 (partial), 3 (segmental), or 4 (necrotic).

As reported in JAMA Surgery, online August 30, RLI grades among the study subjects were: grade 0 (105 patients), grade 1 (47 patients), grade 2 (45 patients), grade 3 (5 patients), and grade 4 (0 patients).

Overall, recurrence-free survival and cancer-specific survival rates after hepatic resection were worse in patients with RLI grade 2 or higher versus grade 1 or lower.

Specifically, recurrence-free survival at three years was 6.4% (grade 2 or higher) versus 39.2% (grade 1 or lower); cancer-specific survival at five years was 20.7% versus 63.7%.

RLI grade 2 or higher was associated with largest metastasis of at least 3 cm (odds ratio, 2.74), multiple CLMs (OR, 2.51), and nonanatomic resection (OR, 3.29).

Worse cancer-specific survival was associated with RLI grade 2 or higher (hazard ratio, 2.90), as well as largest metastasis of at least 3 cm (HR, 1.70) and RAS gene mutation (HR, 2.15).

"We have identified the severity of RLI as an independent predictor of recurrence-free survival and cancer-specific survival in patients undergoing hepatic resection of CLMs," the authors state. "Our results also suggest a dose-response relationship in which increases in RLI grade correlate with incremental decreases in survival."

The retrospective nature of the study and associated biases, including selection bias, were among the study limitations.

Dr. Conrad concluded, "High-quality, anatomically precise liver surgery remains critically important to optimize cancer outcomes."

Dr. Sander Florman, Director of the Recanati/Miller Transplantation Institute at Mount Sinai Hospital in New York City told Reuters Health, "This is an interesting manuscript, and the findings merit publication and consideration. The authors acknowledge the limitations of the study well and also correctly conclude that high-quality surgical techniques are imperative to successful curative liver surgery for colorectal carcinoma metastases."

"The findings are clinically useful, as they corroborate the belief that RLI may be an important prognosticator after resection," he said by email. "These findings alert clinicians involved in the care of these patients that surgical decision making with regard to extent of liver resections and the techniques used may have important implications."

SOURCE: http://bit.ly/2wGsyX1

JAMA Surg 2017.