Surgery remains the principal curative treatment for many patients with localized gastric cancer. In recent decades, laparoscopic gastrectomy has transformed that treatment by allowing surgeons to remove part or all of the stomach through several small incisions rather than a large abdominal opening. Smaller incisions generally mean less postoperative pain, faster mobilization, and a quicker return to normal activities. Yet laparoscopic surgery is technically demanding. Surgeons manipulate long, rigid instruments through narrow access points while viewing the operative field on a two-dimensional monitor. The instruments do not articulate like a human wrist, and even subtle hand movements can be magnified at the tip.

Robotic gastrectomy was developed to address some of these limitations. In robotic systems, the surgeon controls articulated instruments from a console, while a camera provides a magnified, high-definition, three-dimensional view of the surgical field. The system can filter natural hand tremors and translate larger hand movements into smaller instrument motions. Its wrist-like instruments may make it easier to dissect tissue, control blood vessels, and perform delicate suturing in the confined spaces around the stomach and lymph nodes. These features are particularly relevant in gastrectomy, where cancer surgery requires both removal of the tumor and systematic lymph-node dissection while preserving vital structures.

Although robotic gastrectomy has become increasingly widespread, evidence about its practical benefits over laparoscopy has remained mixed. Robotic operations often take longer and require costly equipment, specialized operating rooms, and extensive training. Earlier studies were frequently conducted at high-volume expert centers, making it difficult to determine whether the advantages could be reproduced across a national healthcare system. Researchers from Fujita Health University and collaborating institutions therefore examined contemporary data from Japan’s National Clinical Database, where robotic surgery has expanded substantially since it became eligible for national insurance coverage in 2018.

The study, led by Professor Susumu Shibasaki of Fujita Health University–Okazaki Medical Center, included patients who underwent minimally invasive distal or total gastrectomy between January 2023 and December 2024. Distal gastrectomy removes the lower portion of the stomach, while total gastrectomy removes the organ entirely and requires reconstruction of the digestive tract. To make the comparison more reliable, the investigators used propensity score matching, a statistical method designed to balance important patient and treatment characteristics between groups. After matching, the analysis included 9,743 pairs of patients who underwent robotic or laparoscopic distal gastrectomy and 1,617 pairs who underwent robotic or laparoscopic total gastrectomy.

The clearest disadvantage of robotic surgery was operating time. Robotic distal gastrectomy took approximately 50 minutes longer than the laparoscopic procedure, while robotic total gastrectomy required nearly 70 additional minutes. Longer operations can increase demands on operating-room staff and may raise costs, particularly when hospitals must maintain sophisticated robotic platforms. However, the researchers found that this time penalty was accompanied by several favorable perioperative outcomes. Robotic surgery was associated with 33–40 percent less blood loss for both types of gastrectomy, a finding that may reflect more precise dissection, improved visualization, and greater control during vessel management.

The robotic approach was also linked to a 50–65 percent lower risk of conversion to open surgery. Conversion is sometimes necessary when bleeding, difficult anatomy, dense adhesions, or an inability to safely complete the operation through minimally invasive access makes a larger incision the safer option. Avoiding conversion can preserve the benefits of minimally invasive surgery and may reduce postoperative pain and recovery time. Patients who underwent robotic distal or total gastrectomy also had shorter postoperative hospital stays than matched laparoscopic patients. Among those undergoing distal gastrectomy, robotic surgery was further associated with fewer serious postoperative complications and a lower rate of intra-abdominal infections.

The investigators emphasize that the absolute differences between techniques were not large for every outcome, but their consistency across a broad national cohort is important. Professor Shibasaki described the results as evidence that robotic gastrectomy may achieve a level of minimal invasiveness beyond conventional laparoscopy, which is already a highly refined approach. The findings also point to an evolution in robotic surgery since its introduction into Japanese routine care. Compared with an earlier nationwide analysis conducted before insurance coverage was approved, outcomes in the newer study were more favorable. The researchers attribute this improvement to advances in robotic technology, accumulated surgeon experience, and wider access to structured training.

The benefits were not uniform across all operations. Robotic distal gastrectomy significantly reduced major postoperative complications, but robotic total gastrectomy did not produce a statistically significant improvement in that primary outcome. Total gastrectomy is technically more complex because it involves complete stomach removal and reconstruction, and it is performed less frequently than distal gastrectomy. Lower case volumes may give surgeons fewer opportunities to develop and maintain proficiency with robotic techniques. The study’s retrospective design also means that it can identify associations rather than prove that the robotic platform itself caused the improved outcomes. Although matching reduces differences between patients, it cannot eliminate all forms of bias, including differences in hospital expertise, surgeon selection, tumor characteristics, or institutional resources.

The study was published on May 29, 2026, in the journal Gastric Cancer. Its authors say that continued improvements in robotic instruments, imaging, artificial intelligence-assisted guidance, and surgical education could further refine the procedure over the next decade. At the same time, hospitals will need to consider equipment costs, operating-room time, surgeon credentialing, and equitable patient access before expanding robotic programs. For patients with gastric cancer, the findings offer encouraging evidence that robotic gastrectomy can reduce several short-term surgical burdens, but they do not establish that every patient requires a robot or that robotic surgery improves long-term survival. The most likely future is a more selective and better-trained use of the technology, guided by tumor location, surgical complexity, institutional experience, and patient needs.

Subject of Research: People

Article Title: Clinical advantages of robotic gastrectomy for gastric cancer over conventional laparoscopic approach: a retrospective cohort study using a nationwide registry database in Japan

News Publication Date: 29-May-2026

Web References: https://doi.org/10.1007/s10120-026-01764-5

References: Gastric Cancer. DOI: 10.1007/s10120-026-01764-5

Image Credits: Commander, U.S. 7th Fleet from Openverse

Keywords: gastric cancer, robotic gastrectomy, laparoscopic surgery, minimally invasive surgery, stomach cancer, surgical outcomes, postoperative complications, Japan, National Clinical Database, robotic surgery

Early gastric cancer, often limited to the innermost layers of the stomach wall, presents a formidable obstacle during laparoscopic procedures due to the invisibility of these tumors on the serosal surface viewed intra-abdominally. Historically, surgeons have relied on adjunctive measures such as preoperative dye injections or magnetic clip systems to demarcate tumor sites, methods which suffer from limitations including technical complexity, limited persistence of markers, and difficulties in intuitive lesion detection. Addressing these shortcomings, the Zhejiang University team, led by Lifeng He, has developed a novel strategy that harnesses the unique capabilities of miniaturized soft robots labeled with the near-infrared fluorescent dye Cy5.

This novel approach operates by first implanting a biocompatible metal clip at the gastric lesion during preliminary endoscopic examination. Patients then ingest a capsule containing the soft robots before surgery. These robots, designed with magnetic properties and fluorescent markers, autonomously circulate within the gastric cavity, selectively congregating around the implanted metal clip in response to an applied magnetic field. The resulting fluorescence, observable under near-infrared (NIR) imaging during surgery, distinctly illuminates the tumor region, enabling surgeons to identify and precisely target cancerous tissues with unprecedented accuracy and ease.

The engineers behind this technology emphasize the soft robots’ robust mobility and adhesion characteristics. Despite the highly acidic and dynamic stomach environment, the soft robots demonstrate exceptional capability to navigate intragastric fluid currents, locate the metal clips, and remain firmly attached. Remarkably, their fluorescence signal endures for over eight hours, surpassing typical preoperative fasting durations and ensuring that the tumor remains vividly marked throughout the operative timeline. Such lasting luminescence represents a significant advancement over traditional markers, which often degrade or dissipate too rapidly for practical clinical use.

Validation of this technology was conducted rigorously through animal models; clips were surgically implanted into the stomach walls of rats, followed by oral administration of the Cy5-labeled soft robots. Fluorescent imaging confirmed the robots’ successful accumulation at the clip sites, effectively demarcating the lesion locations. These results suggest that the soft robot system offers a superior and less invasive alternative to existing tumor localization techniques, minimizing procedural complexity and enhancing overall surgical workflow and patient safety.

Beyond its immediate clinical implications, the fabrication technique of these fluorescent soft robots is noteworthy for its simplicity and cost-effectiveness. The researchers describe a streamlined manufacturing process capable of producing these micro-scale devices with consistent quality, leveraging materials compatible with biological tissues and capable of maintaining their structural and functional integrity in harsh gastric conditions. This ease of production bodes well for scalability and eventual clinical translation.

The integration of magnetic responsiveness with long-lasting fluorescent signaling within the soft robots represents a significant breakthrough in medical robotics and imaging. Unlike conventional rigid micro-robots, these soft constructs display flexibility and agility, crucial for maneuvering within complex and confined biological environments like the stomach. Their adhesive mechanisms ensure that once localized at the clip, they maintain position despite peristaltic movements and gastric secretions, enhancing the reliability of surgical navigation.

This research not only bridges the gap between engineering and surgery but also opens new avenues for smart robotic-assisted diagnostic and therapeutic interventions in gastrointestinal oncology. The technology’s versatility could extend to other minimally invasive procedures requiring precise lesion localization, potentially transforming how surgeons approach a variety of cancers or pathological conditions that remain challenging to identify intraoperatively.

Furthermore, the sustained and reliable intraoperative fluorescence offered by these soft robots elevates the standard for real-time tumor visualization. By employing near-infrared signals, the system allows for deeper tissue penetration, reduced background interference, and superior contrast compared to visible light-based dyes, significantly enhancing surgical precision. This facilitates more thorough tumor resections while preserving healthy tissue, ultimately improving patient outcomes and reducing recurrence rates.

The authors envisage that with further refinement and clinical testing, the soft robot platform could be integrated into standard laparoscopic toolsets, complemented by existing imaging infrastructure. This integration promises a seamless user experience enabling surgeons to swiftly identify gastric lesions with minimal additional preparation or complexity, thereby streamlining preoperative workflows and reducing operative time.

This study was undertaken by a multidisciplinary team including Lifeng He, Yu Pan, Wei Jin, Rong Tan, Yanan Xue, Danying Sun, Jingyu Zhang, Pingyu Xiang, Qin Fang, Yue Wang, Rong Xiong, Haojian Lu, and Songmei Lou. Funded by prominent bodies like the National Natural Science Foundation of China, the Key R&D Program of Zhejiang, and supported by other state key laboratories as well as the Xiaomi Foundation, the research stands as a testament to the impactful collaborations advancing medical technology today.

In summary, this novel fluorescent soft robot system represents a paradigm shift in the intraoperative localization of gastric lesions, delivering enhanced accuracy, durability, and ease of use. By overcoming the limitations of current methodologies, this technology not only promises to improve surgical outcomes for early gastric cancer patients but also heralds a new era of smart, robotics-enabled gastrointestinal surgery. The full paper titled “Soft Robots with Cy5: An ‘Intake and Work’ Imaging Technique for Intraoperative Navigation of Gastric Lesion” is available in Cyborg and Bionic Systems and has been assigned DOI: 10.34133/cbsystems.0212.

Subject of Research: Intraoperative localization of gastric lesions using fluorescent soft robots labeled with Cy5.

Article Title: Soft Robots with Cy5: An “Intake and Work” Imaging Technique for Intraoperative Navigation of Gastric Lesion.

News Publication Date: April 11, 2025.

Web References: DOI: 10.34133/cbsystems.0212

Image Credits: Lifeng He, Zhejiang University.

Keywords: Applied sciences and engineering, Health and medicine.