A blood test to detect cancer? Some patients are using them already. [Video]

When her husband was undergoing cancer treatment, Cindy Perez of Southwest Ranches, Fla., learned about a new blood test that could help find early cancers. The 50-year-old said she felt fine, but her husband urged her to take the test anyway.

To her surprise, the blood test – called Galleri – came back positive. Scans revealed a small tumor in her groin and a diagnosis of mantle cell lymphoma, a rare but aggressive form of cancer. She was treated and now, two years later, she’s in remission. “For me, the test was a miracle,” she said. “A real big miracle.”

Many experts believe that such tests, which analyze substances in the blood that might indicate cancer, represent a remarkable new chapter in cancer detection. The tests may be especially useful finding “silent” cancers – such as pancreatic or ovarian cancer – which often don’t cause symptoms until the disease is …