5. Bleeding
Many types of cancer feature some kind of bleeding or propensity to bleeding. For example, colon cancer can cause gastrointestinal bleeding, and prostate cancer can leave blood traces in the ejaculatory fluid. On the other hand, non-solid tumors such as leukemia are often associated with skin rash, bleeding episodes, and longer clotting times.
In solid cancers, bleeding occurs due to the growth of blood vessels to feed new cancer tissue. This new circuitry of blood vessels grows disparately and without following the anatomy of the body. They are thus fragile and prone to bleeding. In leukemia, cancer causes bleeding due to a displacement of blood cells toward the affected line. In other words, white blood cells increase their numbers and take up the space of other cells in the bone marrow, reducing the number of platelets in the blood and compromising the function of blood clotting.