Does Surgery for Colorectal Liver Metastases Release Tumor Cells?

Sharon Worcester

February 04, 2021

For patients with colorectal liver metastasis (CLM), surgical resection is the only hope for cure, but conventional hepatectomy involves mechanical manipulation that could release tumor cells into the bloodstream and result in further spread.

To minimize this risk, an alternative method was introduced in 1992 ― an anterior approach for open right hepatectomies, which involves less manipulation.

However, a trial that compared the two surgical approaches showed no difference between the two in reducing intraoperative tumor cell dissemination.

Circulating tumor cells (CTCs) were detected in 6 of 22 patients (27%) in the anterior hepatectomy group and in 5 of 21 (24%) patients in the conventional hepatectomy group, the study authors report.

Operating time was longer with the anterior approach (221 vs 171 minutes), but intraoperative and postoperative outcomes were similar for the two approaches. Median overall and disease-free survival were also similar (55 vs 73 months and 48 vs 40 months, respectively), as were recurrence patterns, report Nuh N. Rahbari, MD, and colleagues. Rahbari is affiliated with the University of Heidelberg, Heidelberg, Germany.

The findings were published online November 4 in JAMA Surgery.

This "timely" trial "addresses the concerns of many liver surgeons about detaching and shedding cancer cells into the hepatic veins during the initial mobilization of the right lobe," comment the authors of an accompanying editorial, Iswanto Sucandy, MD, from the Digestive Health Institute, AdventHealth, Tampa, Florida, and Allan Tsung, MD, from the Ohio State University, Columbus, Ohio.

"The medial rotation to get the right lobe out of its anatomical confinement is often mechanically rigorous (and potentially traumatic to the tumor and remaining parenchyma), but it is very helpful in facilitating later steps of the operation," they write. "It seems intuitive and easy to extrapolate that this maneuver can increase the release of CTCs into the systemic circulation, thus leading to an inferior oncological outcome."

However, this assumption appears to be unfounded in light of results from this latest study, they point out.

"The most likely reason for these findings is that surgical techniques for CLM resection play a minor role compared with those of tumor biology and patient responses in affecting the metastatic cascade," they suggest.

Tumor Cell Spread Remains a Concern

About 70% of patients experience hepatic or extrahepatic recurrence after conventional hepatectomy, note the study authors, so the concern over tumor cell spread during surgical manipulation remains.

Although their study was limited by small sample size, the absence of bone marrow samples for eight patients, and early discontinuation of the study per protocol, the authors say the findings "do not support further efforts to reduce tumor cell dissemination and subsequent disease recurrence by minimizing intraoperative manipulation."

The findings should "rather prompt strategies to prevent spontaneous tumor cell dissemination and to target minimal residual disease after potentially curative resection."

The editorialists add that the results of this study provide further insights and points for discussion regarding the benefits of minimally invasive approaches to liver surgery, which have been shown in several studies to decrease dissemination of CTCs by reducing surgical manipulation of tumors.

The study was supported by the Department of Surgery, the University of Heidelberg. The study authors and the editorialists have disclosed no relevant financial relationships.

JAMA Surg. 2021;156:31-40. Abstract, Editorial

Sharon Worcester is a reporter for MDedge News, part of the Medscape Professional Network.

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