Promising advancements have been made in the ability to detect and monitor different types of cancers by analyzing blood samples to look for tumor-specific DNA that is circulating in plasma. However, abdominal cancers that have spread (or metastasized) to the abdominal wall can be hard to identify in plasma samples because these cancers contribute a very limited amount of DNA to the circulating blood supply. This is what has prompted Division of Surgical Oncology Associate Professor Dr. Muhammed Murtaza and Assistant Professor Dr. Nabeel Zafar to collaborate on a new $50,000 Translational Basic and Clinical Research Pilot Award they have received from the UW Institute for Clinical and Translational Research and the UW Carbone Cancer Center.
“Patients with a primary gastrointestinal (GI) tract cancer that has spread to the abdominal wall, or the peritoneum, only survive an average of 3-6 months. To change this, we desperately need an accurate biomarker that can detect metastatic peritoneal cancer and that can monitor how the tumor is responding to treatment,” said Zafar. “Since peritoneal fluid is localized to the affected region, it’s our hope that tumor DNA is being shed into this fluid and could serve as this key biomarker.”
Working with collaborators from City of Hope, Murtaza and Zafar plan to analyze peritoneal fluid from 20 patients with late-stage metastatic GI cancer who are either undergoing surgery or who are having a procedure done to remove fluid that has built-up in their abdomen. They also plan to analyze repeated samples over the course of several weeks from 10 of these patients who undergo a form of cancer treatment that directly delivers chemotherapy medications to the abdomen. Murtaza’s lab will then analyze the samples to look for tumor DNA.
“In our initial group of 20 patients, we’ll determine how many have detectable tumor DNA in the peritoneal fluid. We’ll also compare the concentration of tumor DNA in the fluid to the clinical data from the surgery and from imaging to assess how well tumor DNA levels line up with the extent of a patient’s disease burden,” explained Murtaza. “In the 10 patients that we’ll be following over the course of their treatment, we’ll be looking at how levels of detectable tumor DNA in abdominal fluid change over time in response to chemotherapy.”
The research team’s goal is to establish the feasibility of detecting metastatic GI cancer DNA in peritoneal fluid and to evaluate its potential to serve as a biomarker for disease burden and treatment effectiveness.
“Our best estimates suggest that at least 20,000 patients are affected by metastatic peritoneal cancer every year, and these patients currently have limited treatment options and a poor prognosis,” said Zafar. “If this pilot study suggests that abdominal fluid could be a viable biomarker, we can conduct additional research to validate these findings in a larger trial. Ultimately, this line of research could be a game-changer for how we detect this deadly disease and how we monitor treatment progress.”