Patients with gastrointestinal tumors at higher risk of other cancers

Specifically, patients with GIST are more likely to develop other sarcomas, non-Hodgkin's lymphoma, carcinoid tumors, melanoma, colorectal, esophageal, pancreatic, hepatobiliary, non-small cell lung, prostate and renal cell cancers.

"Only 5 percent of patients with gastrointestinal stromal tumors have a hereditary disorder that predisposes them to develop multiple benign and malignant tumors," said Jason K. Sicklick, MD, assistant professor of surgery and UC San Diego Moores Cancer Center surgical oncologist. "The research indicates that these patients may develop cancers outside of these syndromes, but the exact mechanisms are not yet known."

The researchers said further studies are needed to understand the connection between GIST and other cancers, but the findings may have clinical implications.

"Patients diagnosed with gastrointestinal stromal tumors may warrant consideration for additional screenings based on the other cancers that they are most susceptible to contract," said co-author James D. Murphy, MD, assistant professor of radiation oncology and UC San Diego Moores Cancer Center radiation oncologist.

When compared to the United States population, the researchers found that people with GIST had a 44 percent increased prevalence of cancers occurring before a GIST diagnosis and a 66 percent higher risk of developing cancers after diagnosis. The most common tumors were those of the genitourinary tract, breast, respiratory and blood.

Non-Hispanic patients had a higher incidence of other cancers before a GIST diagnosis. Patients whose tumors were smaller than 10 centimeters had a higher probability of a second cancer than patients whose growth was larger. People with tumors smaller than 2 cm had the greatest likelihood of developing additional malignancies, both before and after diagnosis.