Superior mesenteric vessel anatomy features differ in Russian and Chinese patients with right colon cancer: computed tomography-based study

When it comes to right colon cancer surgery, success hinges on more than just skill—it depends on understanding the unique twists and turns of a patient’s blood vessels. For surgeons performing extended lymph node dissection (called D3 dissection) during right hemicolectomy, the position of key arteries and veins near the colon can make or break a procedure. Now, a new study comparing Russian and Chinese patients reveals critical ethnic differences in this vascular anatomy—differences that could change how surgeons plan and perform these operations.

The Study: Comparing Eastern and Western Vascular Anatomy

Led by researchers from I.M. Sechenov First Moscow State Medical University (Russia) and the National Cancer Centre/Cancer Hospital, Chinese Academy of Medical Sciences (China), the study analyzed CT scans from 260 patients with right colon cancer (130 from each country) who underwent laparoscopic or robotic surgery between 2016 and 2018. The goal? To compare how often three major branches of the superior mesenteric artery (SMA)—the vessel that supplies blood to the right colon—appear, and where they sit relative to the superior mesenteric vein (SMV), a key vein nearby.

First, let’s break down the key vessels:

Ileocolic artery (ICA): Feeds the cecum (start of the colon) and appendix.
Right colic artery (RCA): Supplies the ascending colon.
Middle colic artery (MCA): Nourishes the transverse colon.

For the study, researchers defined RCA as a separate branch of the SMA (not sharing a trunk with ICA or MCA). They also categorized whether ICA ran in front of (ventral) or behind (dorsal) the SMV—a detail that directly impacts surgical complexity.

Key Findings: Ethnic Differences That Matter

The results revealed two major differences between Russian and Chinese patients:

More RCA in Chinese patients: Almost 45% of Chinese patients had RCA as a separate SMA branch, compared to just 31% of Russian patients. This matters because a separate RCA makes it easier for surgeons to identify and dissect around the vessel during lymph node removal.
ICA position favors Chinese patients: In Chinese patients, ICA was equally likely to sit in front of or behind the SMV. For Russian patients, however, ICA was far more likely to be behind the SMV (64% vs. 48% in Chinese patients). Why is this a big deal? If ICA is behind the SMV, surgeons must carefully move the vein to access the artery’s origin—a delicate step that increases the risk of bleeding or damage.

The most common anatomy in Russian patients was Type IIa: ICA behind the SMV, no separate RCA, and MCA in front (44% of cases). For Chinese patients, the most common type was Type Ia: ICA in front, no separate RCA, and MCA in front (31% of cases).

Why This Affects Surgery: The Challenge of D3 Dissection

D3 lymph node dissection is the gold standard for right colon cancer—it involves removing all lymph nodes around the SMA branches to reduce recurrence risk. But to do this safely, surgeons need clear access to the base of each SMA branch (where it connects to the main artery).

If ICA is in front of the SMV, surgeons can easily dissect the mesentery (the tissue holding the colon and vessels) to reach the SMA. If ICA is behind the SMV, they must gently retract the vein to expose the artery—a technically demanding step that requires extra time and precision.

As the study notes: “Cases in which the ICA is located behind the SMV require meticulous dissection skills and great care… Without studying the vascular anatomy before the operation, Western surgeons tend to face more difficulties in executing D3 lymph node dissection than Eastern surgeons.”

Context: Eastern vs. Western Trends

The findings align with a 2018 meta-analysis of 45 studies, which found that Eastern populations (like Chinese and Japanese) are more likely to have ICA in front of the SMV and RCA as a separate branch. Western populations (including Russians) tend to have more “challenging” anatomy—with ICA behind the SMV and fewer separate RCA branches.

For example, a 2020 study in Surgical Endoscopy found that patients with ICA behind the SMV had longer surgery times and higher risks of complications during D3 dissection. This makes pre-op CT scans—like those used in the current study—critical for planning.

Limitations and Next Steps

The study has limitations: it’s retrospective (looking back at existing data) and didn’t confirm anatomy during surgery. However, previous research (including a 2015 study in Colorectal Disease) confirms that CT scans are highly reliable for mapping SMA and SMV branches—so the results are trustworthy.

The team also focused only on right colon cancer patients to avoid confounding variables (like differences between healthy people and those with cancer).

The Takeaway: Personalized Pre-Op Planning Is Key

For patients with right colon cancer, the study sends a clear message: ethnicity may shape your vascular anatomy—and your surgical plan. Chinese patients are more likely to have “surgeon-friendly” anatomy (ICA in front, more RCA), while Russian patients face higher odds of complex anatomy (ICA behind SMV).

Surgeons can use pre-op CT scans to map these variations and adjust their approach—whether that means extra time to retract the SMV or a focus on identifying a separate RCA. As the researchers conclude: “These dissimilarities may influence the course and results of extended lymph node dissection for right colon cancer.”

Original Study Details

This study was published in the Chinese Medical Journal in 2021 by Sergey Efetov (Sechenov University), Jun Jiang (National Cancer Centre), and colleagues. The full study is available at doi.org/10.1097/CM9.0000000000001566.

For patients and surgeons alike, the message is simple: understanding your unique anatomy is the first step to safer, more effective cancer surgery.

Was this helpful?

0 / 0