Better understanding and greater use of existing knowledge about the earliest phases of metastasis - the spread of cancer beyond where a tumor originates - will improve outcomes for patients, according to a commentary by a Weill Cornell Medical College physician.
Though metastasis has traditionally been thought of as the end stage of cancer, the process actually begins in tandem with early tumor development, according to recent research highlighted in the September 2013 issue of Nature Medicine by Dr. David Lyden, the Stavros S. Niarchos Professor in the Department of Pediatrics and a professor of cell and developmental biology. Lyden was one of four scientists asked to write about challenges in metastasis research as part of a special meeting of experts on the topic sponsored by the journal in 2012.
Even before cancer cells spread to sites beyond an initial tumor, proteins secreted by that tumor, such as growth factors and tiny particles called exosomes, circulate throughout the body, priming distant sites for metastatic cells to form new tumors. Such growth factors and exosomes are detectable in the bloodstream and in organs through biomarkers and other genetic information. "These micro-particles circulate early, and when you isolate them, you can predict which patient is likely to go on to metastatic disease," Lyden says.
Scientists are investigating therapies that could block production of exosomes or prevent them from fusing with healthy cells away from the tumor. That fusion creates an environment to which metastatic cells are likely to spread and grow. Designing effective therapies that target these early stages of metastasis could reduce the number of cancer patients who ultimately die of it - some 90 percent of patients.
"Traditionally we wait for full-blown metastatic lesions through radiographic assessments," Lyden says. "We shouldn't wait for that stage when we already know that metastasis is taking place as soon as the primary tumor is recognized. Patients should be evaluated right away for these factors. There's no time to wait."