For more than a decade energy-based therapies, such as cryoablation and radiofrequency (RF) ablation, have supplemented or replaced tumor resection via the scalpel—the gold standard for removing tumors. These technologies have made such operations minimally invasive and faster. “Each approach has its strengths and weaknesses,” says Dr. Mahvi. “Cryoablation usually works just fine, but early on, there were some complications in using it on the liver. As the tissue thawed, it would crack, and you’d get lots of bleeding. RF ablation works, but the tumors tend to recur about 20 percent of the time.”

With the early use of both types of ablation, complication rates were higher in larger tumors and in those near major vasculature. A “heat sink” effect that raised or lowered the temperature at the margins of the tumor allowed some malignant cells to survive freezing or burning. Attempting to improve on these therapies, Dr. Mahvi and biomedical engineer John G. Webster, PhD, at UW, conducted some early work with microwaves in animal models. Microwaves heat tissue faster to higher temperatures, which reduces the heat sink effect because less time is available for blood flow to carry the heat away. But because these approaches are so new, evaluating their effectiveness is a “moving target,” according to Dr. Mahvi.

Dr. Mahvi’s research in this area continues with his UW collaborators, focusing on liver, pancreatic, and metastatic colorectal cancers. “David is a world-renowned authority in complex tumors of the hepatobiliary-pancreatic tract,” says Nathaniel J. Soper, MD, Loyal and Edith Davis Professor and chair of surgery. “Our plans include enhancing programs and services in that field as well as expanding the scope of services in GI oncology generally. David is a person of great intellect and integrity, who works well with people across disciplines.”

Dr. Soper, a GI surgeon, knew Dr. Mahvi through various national organizations. For the Society for Surgery of the Alimentary Tract, Dr. Mahvi serves as president-elect. “This is probably the most prestigious GI surgery organization in the U.S.,” says Dr. Soper. “His nomination to be president is a tribute to his accomplishments. It’s a real feather in our cap that we could recruit him here.”

Dr. Mahvi enrolled at the Medical University of South Carolina in Charleston as an MD/PhD student in pathology in the late 1970s. However, during his required surgical rotation, “I found I had no interest in doing anything but surgery,” he recalls. “I was excited to get up in the morning and go to the OR.” The decision to switch was easy, but the conversation with his respected pathology mentor was not.

Despite the specialty change, he was still committed to conducting research. So he searched for the best surgery programs that also required research training. He chose Duke University Medical Center in Durham, North Carolina, where he completed a general surgery residency and a two-year research fellowship in tumor immunology from 1981–89. That same combination of clinical surgery and research drew him to UW’s Section of Surgical Oncology. Dr. Mahvi remarks, “It was exactly the right environment for starting my career.”

Julian C. Schink, MD, GME ’86, today professor of obstetrics and gynecology and chief of the Division of Gynecologic Oncology at Northwestern, met Dr. Mahvi at UW. “David and I collaborated on patient care and got to know each other well,” says Dr. Schink, who had joined the UW faculty in 1992. “In our world of multidisciplinary care, he’s someone whose judgment I absolutely trust. He sees the big picture quickly and takes care of surgical issues with an economy of motion and emotion.”

They also worked together on clinical research and administrative duties for UW and its cancer center. “I was excited to see him come to Northwestern,” continues Dr. Schink. “David always puts patients first, with science and education as top-tier priorities. He appropriately delegates responsibility, expects excellence, and leads by example.”

Dr. Mahvi directed the general surgery residency at UW from 2000–08 and twice won the top residency teaching award (1998 and 2003). “Teaching is a blast,” he says. “I always like having graduate students, residents, and junior faculty around. They bring energy and fresh perspectives—I never look at teaching as a one-way interaction.”

Dr. Mahvi hit the ground running when he arrived at Northwestern. In his first winter quarter, he taught students in NUvention, a course jointly run by the business, engineering, law, and medical schools that focuses on product development and licensing. Much to the students’ benefit, Dr. Mahvi gladly shared his practical experience and expertise. As soon as he arrived on campus, he started working with surgical residents. Says Dr. Soper, “Several residents in their last years of surgical training have told me that the experience on Dr. Mahvi’s service was the best one they’ve had in their entire residency. That’s remarkable given the short time he’s been here.”

Northwestern emphasizes general surgery training, rather than specialized fellowships, for a good reason: nearly 80 percent of U.S. surgical residents do not feel comfortable going directly into practice after five years of general surgery training. Explaining the medical school’s approach to this challenge, Dr. Soper says, “We limit the number of fellowships to provide opportunities for surgical residents to work on the most diverse, complex general surgery cases. In the future, as the caseload increases, we may add a few highly specialized fellowships in strategic areas.”

To provide general surgery residents with cross-disciplinary research experiences, Dr. Mahvi is writing a training grant application with Terrence A. Barrett, MD, professor of medicine and chief of the Division of Gastroenterology, to more closely align research training in their specialties. “We want GI surgery and gastroenterology education to become one, instead of differentiating them based on who’s a surgeon and who’s a gastroenterologist,” explains Dr. Mahvi. “We work together in caring for patients and conducting research, and we have many training opportunities at Northwestern.”

Dr. Mahvi’s research focus changed dramatically from National Institutes of Health-supported basic science studies of tumor immunology and related genetic therapies earlier in his career. “That line of work ran into regulatory problems because of the death of a research participant in a non-cancer clinical trial at the University of Pennsylvania in 1999,” recalls Dr. Mahvi. “Gene therapy research was shut down completely for two years in the U.S., and we had to redo all our protocols. That set us back so far that it was pretty discouraging.”

He was also conducting clinical research on cryo- and RF ablation, including projects with Dr. Schink. Another opportunity in the mid-1990s with a spine surgeon introduced Dr. Mahvi to three-dimensional computer modeling and other engineering techniques applied to designing surgical tools and procedures. Although this work took him outside of his patient care skill set, he found the engineering aspects straightforward and fun. He and his colleagues ended up helping a company design laparoscopic tools to access the spine.

“David Mahvi has a great appreciation for what engineers can do,” says John G. Webster, PhD, professor emeritus of biomedical engineering at UW, who has been collaborating with Dr. Mahvi on energy-based ablation tools since 2000. “He wrote a big grant with us that allowed me to recruit electrical engineering PhD students to do the work on tumor ablation.”

The inventive process starts with Dr. Mahvi describing the clinical problem. “We might propose 10 solutions,” says Dr. Webster. “Then he’ll tell us why nine of them won’t work, and we’ll build the 10th one.” Dr. Mahvi tries out the new tools in porcine models.

One such project aims to improve liver tumor resection. “If you have a tumor near the end of a lobe, you can just cut it off and the lobe grows back,” says Dr. Webster. “But the surgery takes about an hour and may include excessive blood loss. We came up with something like a rake that penetrates through the edge of a tumor. Then you run electricity sequentially through pairs of tines and cauterize a plane through there. You cut away what’s outside that plane and it doesn’t bleed.”

“It’s cool when it works the way we want it to,” adds Dr. Mahvi. “It’s not quite there yet.”

Using computer modeling requires inputting numerous parameters to make the simulation as accurate as possible. For example, normal liver and liver tumor tissues have different electrical characteristics. Due to his large surgical caseload, Dr. Mahvi can send his fellow researchers many different tissue samples so they can make the necessary measurements.

Because this work is supported by federal funds, patents for tools ready for human clinical trials are given to the Wisconsin Alumni Research Foundation—the technology transfer operation for UW. The researchers have no proprietary interests in the final product that reaches the market.

Dr. Mahvi also has a federal Small Business Innovation Research grant for another microwave ablation project with a collaborator at his medical school alma mater. “Attracting federal funding validates your work. People in your field believe your idea is valuable enough to support,” says Dr. Mahvi. He adds with a grin, “However, it’s kind of miserable writing grants all the time.”

At Northwestern Dr. Mahvi has already made immediate contributions to organizing multidisciplinary clinical care teams. He helped revamp the bariatric surgery service that resides in surgical oncology, directed by Alexander P. Nagle, MD, GME ’03, assistant professor of surgery. By fostering a more collaborative service, Dr. Mahvi feels they have streamlined the patient care experience. He shares, “The service received a Center of Excellence award from the American Society for Bariatric Surgery, so the surgeons are good at what they do. We’ve just enhanced the structure so that they can be even better.”

He was also instrumental in developing the new Pelvic Health Center at NMH, codirected by Janet E. Tomezsko, MD, assistant professor of obstetrics and gynecology and head of the Section of Urogynecology; Anne-Marie Boller, MD, assistant professor of surgery in Dr. Mahvi’s division; and John C. Hairston, MD, GME ’01, associate professor of urology. “The team includes colorectal surgery, urogynecology, and urology,” explains Dr. Mahvi. “Someone with a pelvic problem can walk in the door, have a complete workup, and leave with a treatment plan the same day. Previously, seeing those three specialists might take a month.” NMH is building new space for the center, with completion expected later this year.

“These initiatives are easy to achieve here because the school and hospital leadership is terrific,” says Dr. Mahvi. “I feel the energy, and the potential is enormous.”

That includes improving care for people with pancreatic cancer, a disease with a poor prognosis. “Many tumors have essentially been cured by chemotherapy or other methods,” says Dr. Soper. “Pancreatic cancer is nowhere near that. That’s why we need people like Dr. Mahvi and others at the Robert H. Lurie Comprehensive Cancer Center to specifically work on ways to treat these tumors because we usually don’t find them until they’re relatively advanced.”

Dr. Soper expects Dr. Mahvi to expand his own personal practice in surgery of the pancreas, bile duct, and liver and recruit more people to help in those areas. An admirer of Dr. Mahvi’s dry sense of humor and sense of fun, Dr. Soper looks forward to more contributions from the new GI chief. He says, “Dr. Mahvi has demonstrated strengths in research, education, and patient care that make him an exceptional role model for those who aspire to be academic surgeons.”

And as some surgeons-in-training at Northwestern have already found out, Dr. Mahvi has enjoyed teaching them as much as they have relished learning from him.