In general, metastatic cancer is difficult or impossible to treat with surgery because tumor cells have spread throughout the body. But in a 1997 study, researchers find that some colon cancer patients with tumors that have spread to the liver alone can be cured with surgery. In a study of nearly 300 such patients who underwent surgery between 1960 and 1987, about one in four were still alive five years later, and nearly of all of these patients were found to have been essentially cured. A later study finds that use of positron emission tomography, or PET scanning, can identify some liver metastases that would have gone unnoticed before, helping surgeons in the study to achieve a cure rate above 50 percent for patients with metastatic disease.

Genetic tests become available for familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer, also known as Lynch Syndrome; these inherited disorders are known to increase colorectal cancer risk. The new tests enable physicians to identify people with these conditions and monitor them more closely for cancer or pre-cancerous polyps through regular colonoscopy screenings.

Surgeons develop and refine transanal endoscopic microsurgery (TEM) – surgery performed via a scope inserted into the anus to remove early-stage rectal cancers less invasively. This approach is especially important as an option for patients who are too ill or elderly to undergo an open abdominal operation.

In 1967, the guaiac fecal occult blood test (FOBT) is introduced as a screening test for colorectal cancer, one of the most common forms of cancer. This simple and inexpensive tool detects the presence of blood in stool, a sign that cancerous or precancerous growths (called polyps) may be present. Within the next few years, two new screening techniques – flexible sigmoidoscopy and colonoscopy – enable physicians to examine the colon using a small camera attached to a flexible lighted tube. The widespread use of these approaches leads to better detection of precancerous polyps and early stage cancers that are usually curable with surgery. Over the coming decades, routine screening contributes to major reductions in colorectal cancer mortality – a total decline of more than 40 percent since 1975.