In a new study, researchers at Stanford University found that, contrary to the widely held belief that cancers usually spread once the primary tumor is large and detectable, some colorectal cancers spread before the original tumor is large enough to be detected.
While the study may provide good information for doctors who are continuing to research the disease, it shouldn’t change the message that people get about getting screened early and regularly, according to Dr. Heather Yeo, Colorectal Surgeon and Surgical Oncologist at Weill Cornell Medicine and NewYork-Presbyterian. “We know that colonoscopy decreased colon cancer rate,” she says.
Read More“They had 23 patients that they had a number of samples from, and only 21 samples were evaluable. They had 17 in their sample that, when they used computer modeling, many of these were very aggressive cancers,” says Dr. Yeo. Very aggressive forms of colorectal cancer might metastasize while the original tumor is still undetectable.
Dr. Yeo emphasizes that within colorectal cancer, some types are more aggressive than others, and that some more aggressive cancers might that spread early in the disease might have been the majority of patients in the study. “We know that some cancers have certain mutations that are more aggressive than others,” she says.
But while the study may suggest the disease can spread in some cases before it can be detected, this is not the case with most colorectal cancer. “I know, based on taking care of stage 2 patients, those patients have a 90 percent cancer of being cancer free after surgery alone.”
So it’s important to know that this isn’t a good reason not to get screened for colorectal cancer. “This shouldn’t dissuade anyone from getting colonoscopy. The population of people with colorectal cancer has been going down over the past twenty years because we’ve been screening,” says Dr. Yeo.
After the study, researchers looked at data from almost 3,000 patients, some with metastatic colorectal cancer, some without, to see if they could identify mutated genes with predicted spread of the disease. One mutation called PTPRT was found to be present in about a quarter of colorectal cancers.
When PTPRT is mutated, it can have the effect of increasing production of a protein called STAT3, which promotes cell survival. Not everyone with the gene with colorectal cancer will see colorectal cancer spread, but the research shows that people with this gene mutation are likely to see colorectal cancer metastasize.
And while there aren’t any approved drugs that target this protein, there are a number of clinical trials attempting to inhibit STAT3, or stop it from being effective, in different types of cancer, two of which focus on colorectal cancer specifically.
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