You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is A 68 year old male is diagnosed of having colorectal cancer. What is the commonest presentation of Ca ascending colon ? and explain in detail?
The presentation depends on the site of the cancer: Right colon cancers: weight loss, anemia, occult bleeding, mass in right iliac fossa, disease more likely to be advanced at presentation. Left colon cancers: often colicky pain, rectal bleeding, bowel obstruction, tenesmus, mass in left iliac fossa, early change in bowel habit, less advanced disease at presentation. A tumor in the left (descending) colon is likely to cause obstruction at an earlier stage, because the left colon has a smaller diameter and the stool is semisolid. Cancer tends to encircle this pa of the colon, causing alternating constipation and frequent bowel movements before obstruction. A tumor in the right (ascending) colon does not cause obstruction until late in the course of the cancer, because the ascending colon has a large diameter and the contents flowing through it are liquid.