It is critically important that colorectal cancer patients undergo colonoscopy after surgery to ensure that they do not have a second colon cancer, and to find and remove any additional polyps.

According to new recommendations from the US Multi-Society Task Force on Colorectal Cancer, the evidence shows that post-operative colonoscopy is associated with improved overall survival for colorectal cancer patients.

Between 0.7 and 7 percent of colorectal cancer patients have a second, concurrent cancer.

These recommendations update the 2006 US Multi-Society Task Force consensus guideline, which addressed the use of endoscopy for patients after colorectal cancer resection.

The updated document focuses on the role of colonoscopy in these patients, as well as reviews possible adjunctive roles of faecal testing and CT colonography in post cancer resection patients.

Patients who have surgery to remove colorectal cancer should receive colonoscopy on the following schedule:

1. Before cancer resection surgery, if possible. If not, colonoscopy should be performed within three to six months after surgery.
2. One year after surgery or one year after the perioperative (pre-surgery) colonoscopy.
3. Four years after surgery or the perioperative colonoscopy.
4. Nine years after the perioperative colonoscopy.

Subsequent colonoscopies should occur at five year intervals until the benefit of continuing surveillance is outweighed by diminishing life expectancy.

If pre-cancerous polyps are found, the intervals for surveillance should follow published guidelines for polyp surveillance.

This does not apply to patients with Lynch syndrome.

Review the "Guidelines on Genetic Evaluation and Management of Lynch Syndrome: A Consensus Statement by the US Multi-Society Task Force on Colorectal Cancer" for more information.

Additional considerations in surveillance of rectal cancer

• Patients with rectal cancer have a higher risk of local recurrence compared to those with colon cancer. This is particularly true of those patients with locally advanced rectal cancer who are not treated pre-operatively with radiation and chemotherapy, and in general those rectal cancer patients who are operated on using surgical techniques that do not fall under the method called "total mesorectal excision." Patients at high risk of local recurrence of rectal cancer should be considered for additional surveillance:
• Local surveillance with flexible sigmoidoscopy or endoscopic ultrasound should occur every three to six months for the first two to three years after surgery.
• These surveillance measures are in addition to recommended colonoscopic surveillance for second cancers.

Alternatives and adjuncts to colonoscopy

• Patients who have an obstructive colorectal cancer and, therefore, cannot undergo a complete colonoscopy, should receive CT colonography as the best alternative to exclude synchronous neoplasms. Patients can also undergo double-contrast barium enema, if CT colonography is not available.
• There is little evidence to support the routine use of faecal immunohistochemical tests or faecal DNA tests for surveillance after colorectal cancer resection.

Colorectal cancer is the second leading cause of cancer death for both men and women combined in the US More than 132,000 new cases of colorectal cancer were estimated to be diagnosed in 2015 and of those, 70 to 80 percent were expected to undergo surgical resection with intent to cure the disease.

Up to 40 percent of patients with locoregional disease (recurrence at or near the original tumour site after removal) will develop recurrent cancer, 90 percent of which will occur within five years.

The US Multi-Society Task Force is composed of gastroenterology specialists with a special interest in colorectal cancer, representing the American Gastroenterological Association, the American College of Gastroenterology and the American Society for Gastrointestinal Endoscopy.

Source: American Gastroenterological Association