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Certain People with Colorectal Cancer Are Less Likely to Get an Important Test

Colorectal cancer starts in the colon or rectum. If the cancer spreads to other parts of your body, it is called metastatic or stage IV colorectal cancer. If colorectal cancer has spread to other parts of the body, the KRAS test may help patients and doctors decide on the right treatment.

What Is the KRAS Test?

Genes act as instructions and contain information to build and maintain cells in the body. Humans inherit one set of genes from their mother and one set of genes from their father.

A KRAS test looks for changes in the KRAS gene. The KRAS gene makes a protein that helps control how cells age and die. Mutated (changed) forms of the KRAS gene have been found in some kinds of cancer. These changes may cause cancer cells to grow and spread in the body.

In 2011, the National Comprehensive Cancer Network recommended a KRAS test for people with metastatic colorectal cancer (cancer that has spread outside of the colon and rectum). People who don’t have changes in their KRAS gene get different treatments than people with changes.

How the Study Worked

This study looked at how many people with metastatic colorectal cancer got a KRAS test. The researchers used records from cancer registries in several states. Cancer registries are agencies that keep track of every case of cancer.

The researchers looked at which groups of people with metastatic colorectal cancer were least likely to get the KRAS test. People were placed in groups based on their race and ethnicity, age, sex, where they lived, and other factors. Researchers then compared groups by the percentage of people who got a KRAS test. For example, when comparing groups by race and ethnicity, they compared rates of testing for blacks, whites, American Indians/Alaska Natives, Asians/Pacific Islanders, and Hispanics.

What the Study Found

Overall, only about one person out of four with metastatic colorectal cancer gets a KRAS test. People in certain groups are even less likely to get tested. Not getting the test and the right medicine sooner means that more people in those groups may die from colorectal cancer.

  • Only 992 out of 3,608 people with metastatic colorectal cancer in all of the groups combined got a KRAS test. This is about 27%, or about 1 person out of every 4.
  • Those who were less likely to be tested were black people, Hispanic people, older people, people living in certain states, people on Medicaid or Medicare, and people living in areas where education levels were lower.
  • Researchers didn’t find as much difference between people when grouped by sex, whether they lived in a city or in a rural area, whether or not they lived in a poor area, or whether or not they had another health problem along with metastatic colorectal cancer.


Rico A, Pollack LA, Thompson TD, Hsieh M, Wu XC, Karlitz JJ, West DW, Rainey JM, Chen VW. KRAS testing and first-line treatment among patients diagnosed with metastatic colorectal cancer using population data from ten National Program of Cancer Registries in the United States. Journal of Cancer Research & Therapeutics. 2017;5(2):7–13.