CU Department of Surgery Resident Wins Rising Star Award for Gallbladder Cancer Research

Andrii Khomiak, MD, a resident in the University of Colorado Department of Surgery, is off to a good start in the first year of the research portion of his residency. 

His study on better ways to predict survival and the need for chemotherapy in patients undergoing surgery for gallbladder cancer has netted him a Rising Star Award  — presented for the best paper by a junior surgeon — from the American Hepato-Pancreato-Biliary Association.

Khomiak received the award at the association’s annual meeting in April.

Mungo and Khomiak at the American Hepato-Pancreato-Biliary Association annual meeting.

“I gave a 10-minute talk where I dove into all the details of our study,” he says. “The competition was rough — there were only five papers out of thousands that were submitted to the conference that were selected for this talk. There was a peer-review process that scored the presentations, and I was very excited and felt lucky to get the award. It was a great experience.”

Finding the ratio

Khomiak’s research looks at the effectiveness of a method called lymph node ratio to determine a patient’s chances of survival after surgery for gallbladder cancer, and if the patient is likely to benefit from chemotherapy after the surgery.

“When you encounter gallbladder cancer, it’s not always clear who would benefit from chemotherapy after the surgery,” says Khomiak, who came to Colorado from Ukraine to complete his residency. “Lymph node ratio — the number of cancerous lymph nodes divided by the total number of lymph nodes that were taken out of the body — is one of the markers that is used for different cancers. It characterizes how much disease has spread across the lymph nodes that we were able to examine.” 

Analyzing data from the National Cancer Database, Khomiak found that patients with a low lymph node ratio had longer survival rates, while those with lymph node ratios higher than 30% were more likely to benefit from chemotherapy after surgery.

“Our endpoint for this study was survival,” Khomiak says. “For patients who had a lymph node ratio higher than 30% — so a lot of lymph nodes involved — we showed that chemotherapy impacted their survival rates much more significantly than patients without lymph node metastasis or patients with a lymph node ratio of less than 30%.”

A new tool

Benedetto Mungo, MD, assistant professor of surgical oncology and Khomiak’s research mentor in the CU Department of Surgery, says that currently, most cancer surgeons who perform surgery for gallbladder cancer strive to obtain adequate lymph node numbers. But since typically only six or fewer nodes are removed during gallbladder cancer surgery, often due to anatomic variation and technical challenges, lymph node ratio, he says, may provide a more complete picture of how far the cancer is likely to have spread. 

“Currently, if the patient has one metastatic lymph node, it puts them in an N-1 stage group,” Mungo says. “But it doesn’t matter if the patient had one lymph node extracted — so one of one is positive — or if the patient had 100 lymph nodes extracted, and he has one of 100 positive. There's a difference in sample size there.”

Lymph node ratio, Mungo says, tries to characterize not only the total number of extracted lymph nodes that are positive, but the ratio between the nodes examined and those that were positive.

“Some authors argue that this is better than what's currently in place for the staging system,” he says. “Our data alone cannot replace the whole staging system that's been in place for many years, but we hope to complement the current guidelines.”

Boon for patients

Beyond predicting survival, lymph node ratio can be used as a clinical tool to determine a patient’s trajectory and if they are a good candidate for chemotherapy, Khomiak says.

“If the ratio is high, you know that patient has a cancer that is more aggressive, is more advanced, and likes to spread,” he says. “Those are the patients in which you should be strongly considering chemotherapy, because they're the ones that are most likely to benefit from it. It doesn’t give you all the answers, but it's a piece of the puzzle.”

Not only does lymph node ratio help a surgeon better understand a patient’s prognosis; it can also help the patient get a better picture of their disease and its treatment.

“It's an easy-to-explain tool to help them understand where they stand,” Khomiak says. “If lymph node ratio will ultimately be validated as a clinical tool and become part of official guidelines, in the clinic, you could explain that, ‘You have this percentage of lymph nodes involved, and based on our study, this means you're less likely to survive as long as a patient with less lymph node involvement. We think, because of this, you may want to seriously consider adjuvant chemotherapy.’

“It can mean better understanding for them as far as where they stand in terms of the disease, and better understanding and rationale for undergoing additional treatment,” he continues. “Those can be stressful conversations, and understanding your treatment and understanding your prognosis is very helpful.”

Featured image: Khomiak presents his research at the American Hepato-Pancreato-Biliary Association's annual meeting in April.