Robotic versus Laparoscopic Gastrectomy with Splenic Hilar Lymph Node Dissection: Short-Term Outcomes from a Propensity Score-Matched Study

Gastric cancer, a disease that begins in the stomach, remains a leading cause of death worldwide, particularly in East Asia. When surgeons operate to remove this cancer, their goal is not just to take out the tumor but to clear away the nearby lymph nodes, which are small, bean-shaped structures that act as filters for the body's immune system. If cancer cells have spread to these nodes, removing them is crucial for a patient's long-term survival. However, the location of these nodes matters greatly. For tumors on the upper part of the stomach that reach the outer curve, the lymph nodes near the spleen become a critical target. The spleen is a vital organ located just behind the stomach, and the area where the blood vessels connect it to the stomach is a tight, crowded space filled with delicate vessels and the tail of the pancreas. For decades, the standard way to ensure these nodes were removed was to simply take out the spleen along with the stomach. Yet, research later showed that removing the spleen when it is not strictly necessary causes more bleeding and complications without helping the patient live longer. This shifted the goal toward a much harder task: removing the cancerous nodes while carefully leaving the spleen and pancreas untouched.

This delicate operation can be performed using traditional open surgery, but modern medicine increasingly relies on minimally invasive techniques. Surgeons can use long, thin tools inserted through small holes in the abdomen, either guided by a standard laparoscopic camera or by a robotic system. The robotic system offers a three-dimensional view and instruments that can bend and rotate like a human wrist, theoretically allowing for finer movements in tight spaces. Despite the growing use of these robots, it was not clear if they truly offered a measurable advantage over standard laparoscopic tools when tackling the specific, difficult task of clearing the lymph nodes near the spleen. A team of surgeons at the International University of Health and Welfare Nasu Medical Center in Japan set out to answer this question by comparing the two approaches in patients who required this specific, spleen-sparing procedure.

The researchers looked back at the medical records of 113 patients who underwent surgery for stomach cancer between 2008 and 2026. All of these patients had tumors that involved the outer curve of the stomach, meaning the lymph nodes near the spleen needed to be removed. Of these patients, 69 had the procedure done with standard laparoscopic tools, while 44 had it done with a robotic system. Because the two groups of patients were not perfectly identical—some were older, some had different tumor sizes, and some had received chemotherapy before surgery—the researchers used a statistical method to pair them up. They matched 35 patients from the robotic group with 35 patients from the laparoscopic group who had very similar characteristics, such as age, body mass, and the extent of their disease. This allowed for a fair comparison of how the two surgical methods performed in similar hands and on similar bodies.

The results showed distinct differences in how the surgery unfolded. Patients in the robotic group lost significantly less blood during the operation. While the laparoscopic group lost a median of 30 milliliters of blood, the robotic group lost almost none, with a median of zero milliliters. This difference was not just a matter of numbers; it reflected the surgeon's ability to control bleeding more precisely in the crowded space near the spleen. Furthermore, the robotic approach appeared to be gentler on the pancreas. After surgery, a tube is often left in the abdomen to drain fluid, and doctors check the level of amylase, an enzyme produced by the pancreas, in that fluid. High levels can indicate that the pancreas was irritated or injured during the operation. In the matched group, the fluid from the robotic patients had much lower levels of this enzyme compared to the laparoscopic patients, suggesting less trauma to the nearby organ.

Perhaps most importantly for cancer treatment, the robotic surgeons were able to retrieve more of the specific lymph nodes they were targeting. The goal was to clear the nodes near the spleen, and the robotic group yielded a slightly higher number of these specific nodes compared to the laparoscopic group. This suggests that the extra dexterity of the robotic instruments allowed the surgeons to reach into the tight corners of the anatomy more effectively. However, the robotic surgery did take a bit longer. The average time spent in the operating room for the robotic group was about 32 minutes longer than for the laparoscopic group, though this difference was on the edge of statistical significance. Despite the longer time, the patients did not stay in the hospital any longer, and the rates of serious complications were similar between the two groups. In fact, no patients in either group developed a leak from the area where the spleen's vessels were cleaned, and no patients died in the hospital from the procedure.

The study also examined the learning curve, or how the surgeons improved over time. When looking at the robotic cases chronologically, the time it took to perform the surgery dropped steadily during the early years and then leveled off, indicating that the team became more efficient as they gained experience. In contrast, the time for the laparoscopic cases fluctuated without a clear pattern of improvement over the same period. This suggests that while the robotic system has a learning phase, once the surgeons master it, the procedure becomes consistently efficient. The researchers noted that their study had limitations, primarily because it was a single-center study conducted over a long period where medical care standards changed, and the sample size was relatively small. They emphasized that while the short-term results favored the robotic approach in terms of blood loss, pancreatic safety, and node retrieval, larger studies are needed to confirm if these advantages translate into better long-term survival for patients.

Ultimately, this work provides evidence that robotic assistance can make the difficult task of removing lymph nodes near the spleen safer and more precise. It allows surgeons to spare the spleen and protect the pancreas while still clearing the cancer effectively, without increasing the risk of complications or extending the hospital stay. The findings support the idea that for this specific, anatomically challenging part of stomach cancer surgery, the robotic platform offers a tangible technical benefit over standard laparoscopy, provided the surgical team has the necessary experience to navigate the learning curve.