Colorectal cancer is cancer of large intestine. Large intestine is last part of intestine where mainly water is absorbed. It is group of cancer mainly divided into right sided colon cancer, left sided colon cancer and rectal cancer.

Right side: Stool is liquid here hence main symptom is weakness, fatigue due to blood loss causing anemia, sometimes lump in abdomen.

Left side and rectum: Here symptoms are mainly obstructive due to constricting nature of tumor. They have change in bowel habit.

All person with persistent above symptoms for more than 3 weeks must consult oncologist.

First and most important is clinical examination by finger(Per rectal examination). Many can be easily confused with piles.

Colonoscopy and Biopsy: Endoscopic examination of large intestine and biopsy is done to assess tumor location, coexisting another tumor, precancerous lesions CT scan of abdomen and chest for cancer staging.

Colon Cancer: Main and only curative treatment is surgery. Chemotherapy is used as supportive therapy for high risk stage 2 and all stage 3 colon cancer.
Stage 4 cancer require only chemotherapy and sometimes diversion procedure for stool.

Rectal Cancer: Except very early cancer, most require presurgery chemoradiotherapy (NACTRT). It decreases chances of cancer recurrence drastically. Also aid in preserving normal passage of stool, avoiding permanent bag (colostomy).

Conventional method was open surgery. In complicated and obstructive cases, it is still preferred method.
Disadvantage: High wound infection rate, large scar, pain due to big scar

Laparoscopic Surgery: It is really boon and has become gold standard. Due to magnified view, cancer clearence is better, chances of injury to nerves is less, blood loss minimal.
Due to increase in reach, many cases where permanent colostomy was planned, can be converted to sphincter preserving surgery. Good training from good cancer institute is must to perform this surgery correctly.

Robotic Surgery : Principle and technique are same as laparoscopic surgery. Cost is almost double. Operating surgeon is more important as it is just a tool. (robot is not performing surgery)

Colorectal cancer are mainly due to tobacco, alcohol, heavy consumption of non veg food. Obesity is another factor. Some are familial. Inflammatory bowel disease is risk factor.

Avoiding/quitting tobacco, alcohol, weight control with physiotherapy, high fibre diet is important.

Annual Stool Examination of Occult Blood, colonoscopy once in 3 year can identify precancerous lesions (adenoma), treating of whom can prevent cancer development.