Study Shows Cancer Can Spread Undetected, Before Tumor Develops

Research has found that cancerw cells can spread unseen, before a tumor develops, and leave a tickingtime bomb in the body. But the scientists who made the discovery say it soon may bepossible for doctors to target these “silent” cancer cells and kill them before they can kill the patient.The researchers said the ability of these early cancer cells to spread while remaining silent for years explains why a patient can die a long time after being treated for what was thought to be a benign tumor, or even no tumor at all.Loading...Experts say 5 percent to 8 percent of cancer patients die of what’s called cancer ofunknown primary, or CUP. This phenomenon occurs when the disease metastasizes without doctors having found a primary tumor.In other cases, cancer can besuccessfully treated but return decades later. For instance, small growths can be surgically removed from breast cancer patients, but the women will die of the disease 20 or 30 years later.Working with mouse modelsof breast cancer, U.S. and German researchers discovered biomarkers to identify these abnormal, silent cancer cells that travelfrom the site of an early tumor and settle in the bone marrow or lungs.These biomarkers can show whether the cells are seeds of metastasis, suggesting it might be possible to give people with cancer a definitive prognosis.