9) Black stools
We have already mentioned vomiting and how such reflex would sometimes turn into blood vomiting. Cancer cells grow new blood vessels, and they need to do that in order to grow bigger and prevent cancer cell death due to lack of nutrients or insufficient oxygen. In the process, tumors start growing aberrant blood vessels with a thin lining that’s very susceptible to bleeding. As the tumor grows bigger, there’s more contact and wear down of the structures, and these aberrant blood vessels become easily damaged, resulting in gastrointestinal bleeding.
One of the manifestations of gastrointestinal bleeding is vomiting blood, and the other is black stools. When the blood goes through all of the digestive tube it becomes rotten and changes color to a dark red or black. It may also start smelling as the gastrointestinal microbiota does its part. In the end, patients start passing black stools frequently, and this is a sign of gastrointestinal bleeding that doctors should trace all over the digestive tube.
Studying black stools would require to perform a stool test, a blood test, imaging techniques, and even more invasive procedures such as endoscopy. This is often the only way to determine what is wrong and may become the diagnostic procedure to detect esophageal cancer and even perform biopsies to know what type of cancer is it.
