Cancer is often misdiagnosed, putting patients' lives at risk. While many misdiagnoses have to do with the difficulty of finding cancer, some are caused by negligence of doctors. Failing to follow up with test results, confusing patient charts and other behaviors can lead to patients who suffer from progressing cancer when they should be getting treatment.
The reason cancer is hard to find is that it's simply very small. There are millions of cells in the human body, and diagnosing cancer means finding the one or two cells that look different. There are no tests created simply for the diagnosis of cancer, although blood tests like a CA 125 can indicate that cancer is present by looking for cancer proteins in the blood.
Sometimes, small groups of cells aren't big enough to identify yet, and other times, cancer cells that are in larger groups are hidden in scans by the body's organs, bones or tissues. When they aren't identified at this early stage, they have the ability to metastasize, which means to spread. As the cancer spreads throughout the body, the patient may start to observe changes like odd lumps, which signal that a tumor is growing. Not all tumors are cancerous, but they can be a sign of cancer in the body.
Other symptoms of cancer mimic problems like colds or the flu. Fatigue, coughing or jaundice can all be signs of cancer as well as other medical conditions, making it harder for the doctor to diagnose exactly what the problem is. In most cases, doctors can persist and identify cancer with the right biopsies and scans, but patients must be their own advocates in seeking this care. If a doctor refuses to complete more tests or clears you when you're still ill, you might have a case for negligence or malpractice.
Source: How Stuff Works, "Why is it so difficult to find cancer cells?," Molly Edmonds, accessed Sep. 28, 2016