User access blocked after policy breach
Minimally invasive surgery is giving patients with rectal cancer new options that preserve function and speed recovery, according to a colorectal surgeon at UCSF Health.
Dr. Mark Zhao, who specializes in colorectal cancer and pelvic floor disorders, said carefully selected patients with large benign rectal polyps or early-stage rectal cancers may qualify for transanal minimally invasive surgery, or TAMIS. The procedure avoids abdominal incisions and often allows same-day discharge. Unlike traditional open surgery, which requires a large abdominal incision and extended hospital stays, TAMIS accesses the rectum through the anus using specialized instruments. The technique relies on high-definition imaging and precision tools to remove tumors while maintaining the structural integrity of the rectum, which is critical for preserving bowel control and sexual function.
Same-day discharge, less pain
In an interview, Zhao said TAMIS can maintain anorectal function while delivering outcomes comparable to traditional surgery. Patients typically experience less pain and faster recovery. “Early referral is important because patients may lose the opportunity for these local excision options as lesions become larger or more advanced,” he said. “But whenever it’s oncologically appropriate, the TAMIS procedure allows us to preserve rectal and anorectal function while avoiding abdominal incisions.” The window for TAMIS eligibility is narrow, as tumors that grow beyond a certain size or depth may require more extensive resection. Zhao stressed that multidisciplinary evaluation—including input from oncologists, radiologists, and pathologists—is essential to determine whether a patient’s cancer can be safely removed with TAMIS. Factors such as tumor location, grade, and molecular characteristics are carefully assessed to ensure the procedure meets oncologic standards while maximizing functional preservation.
The approach is not suitable for every patient. Zhao emphasized that oncologic principles—removing the cancer completely—remain the priority. TAMIS is best for those with smaller, less aggressive tumors that do not require more radical resection. Patients with locally advanced cancers or those involving lymph nodes typically need more full surgery, such as a low anterior resection or abdominoperineal resection, which may involve removing part of the rectum or anus. Zhao’s team uses advanced imaging techniques, including MRI and endoscopic ultrasound, to stage tumors accurately and determine the most appropriate surgical approach. Even when TAMIS is not an option, these imaging tools help tailor treatment plans to minimize unnecessary tissue removal while ensuring clear margins.
Related: Morning Energy Boosters for a Healthy Start
A single incision for complex procedures
For patients who need abdominal surgery, Zhao’s team at UCSF has been evaluating the da Vinci SP single-port robotic platform. The system allows surgeons to perform complex procedures through a single incision while maintaining the same oncologic standards as conventional minimally invasive techniques, which often require multiple small incisions. The da Vinci SP features a flexible camera and articulating instruments that can be inserted through a single 2.5-centimeter port, providing enhanced maneuverability in tight spaces like the pelvis. This is particularly advantageous for rectal cancer surgery, where precision is critical to avoid damaging surrounding structures such as the urethra, bladder, or nerves responsible for continence and sexual function.
“Our group has been involved in the early development and clinical evaluation of the single-port robot,” Zhao said. “That gave us substantial experience—not only with the technology itself, but also in how we should carefully select patients for its implementation.” UCSF was among the first institutions to test the da Vinci SP in clinical settings, allowing Zhao’s team to refine techniques for rectal cancer resection. The system’s 3D high-definition visualization provides a magnified view of the surgical field, improving the surgeon’s ability to identify and preserve critical anatomy. Unlike multi-port laparoscopic surgery, which requires several incisions for instrument placement, the single-port approach reduces scarring. However, the learning curve for the technology is steep, and not all surgeons are trained to use it effectively.
The platform is still being refined, and not all patients will benefit. But for those who do, the single-incision approach can further reduce trauma and accelerate recovery without compromising cancer removal. Zhao’s team continues to assess which patients are the best candidates for these techniques. The goal, he said, is to balance innovation with safety—ensuring that new methods do not come at the expense of long-term outcomes. Ongoing studies at UCSF are evaluating the durability of functional and oncologic results from TAMIS and single-port robotic surgery. Zhao also collaborates with engineers and industry partners to improve robotic instrumentation, such as developing smaller, more flexible tools that can handle the confined spaces of the pelvis. As these technologies evolve, the criteria for patient selection may expand.
For now, early referral remains critical. Patients who are evaluated sooner have more options, including those that may spare them from more invasive surgery. Zhao encourages primary care physicians and gastroenterologists to refer patients with rectal polyps or early-stage cancers promptly, as delays can limit the availability of minimally invasive techniques. He also advocates for increased patient education about these options, noting that many individuals are unaware that surgery for rectal cancer no longer always requires a large incision or prolonged recovery.
