STANFORD, Calif. Tumors can grow for 10 years or longer before currently available blood tests will detect them, a new mathematical model developed by Stanford University School of Medicine scientists indicates. The analysis, which was restricted to ovarian tumors but is broadly applicable across all solid tumor types, will be published online Nov. 16 in Science Translational Medicine.
"The study's results can be viewed as both bad and good news," said Sanjiv "Sam" Gambhir, MD, PhD, professor and chair of radiology and the study's senior author. (Sharon Hori, PhD, a postdoctoral scholar in Gambhir's laboratory, is the lead author.)
The bad news, Gambhir said, is that by the time a tumor reaches a detectable size using today's available blood tests, it is likely to have metastasized to other areas of the body, making it much more deadly than if it had been caught early on. "The good news is that we have, potentially, 10 or even 20 years to find the tumor before it reaches this size, if only we can improve our blood-based methods of detecting tumors," he said. "We think our mathematical model will help guide attempts to do that."
The study advances previous research about the limits of current detection methods. For instance, it is strikingly consistent with a finding reported two years ago by Stanford biochemistry professor Patrick Brown, MD, PhD, that current ovarian cancer tests could not detect tumors early enough to make a significant dent in the mortality rate. There is a push to develop more-sensitive diagnostic tests and find better biomarkers, and Gambhir's new model could be an essential tool in this effort. It for the first time connects the size of a tumor with blood biomarker levels being shed by that tumor.
To create their model, Gambhir and Hori used mathematical models originally developed to predict the concentration of drugs injected into the blood as they move in and out of the bloodstream. The investi
|Contact: Bruce Goldman|
Stanford University Medical Center