Final answer:
Melena is more common than hematochezia for colorectal cancer.
Step-by-step explanation:
Melena is more common than hematochezia for colorectal cancer. Melena refers to the passage of black tarry stools, which is caused by bleeding in the upper gastrointestinal tract. On the other hand, hematochezia refers to the passage of fresh, bright red blood in the stool, which is usually caused by bleeding in the lower gastrointestinal tract. Colorectal cancer commonly causes melena because the tumor is located higher up in the gastrointestinal tract. However, in some cases, it can also cause hematochezia if the tumor is located closer to the rectum or anus.
Melena (Upper Gastrointestinal Bleeding): If colorectal cancer causes bleeding in the upper part of the colon or from lesions in the small intestine, melena may be observed. However, melena is not the typical presentation for colorectal cancer.
Hematochezia (Lower Gastrointestinal Bleeding): Colorectal cancer commonly presents with hematochezia, especially if the bleeding occurs in the lower part of the colon or rectum. Hematochezia is more likely to be associated with colorectal cancer than melena.
It's essential to note that these are generalizations, and individual cases may vary. The presence of blood in the stool should always be evaluated by a healthcare professional, and diagnostic procedures, such as colonoscopy, may be necessary to determine the cause and location of bleeding, as well as to diagnose colorectal cancer.