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Colorectal cancer: why is the diagnosis of RAS important?

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“When selecting the type of treatment required by the patient with advanced disease, the oncologist will ask the laboratory to determine if there is such an alteration or not of RAS to make a decision.”

Colorectal cancer is one of the most frequent in UK, ahead of other more known as breast cancer. In our country each year 44,000 new cases are diagnosed, 25 percent in a metastatic state; that is, the cancer has spread to other areas of the body. However, although the figures are high, the evolution in the diagnostic techniques and in the treatments are getting that the rates of cure are increasingly higher.

One of the factors that are contributing to this revolution in therapies is precision medicine, formerly known as personalized medicine. It is a new approach in which the decisions of treatment and management of patients are based on the study of genes or molecules. Depending on the alterations that we find, we will indicate some drugs or others. This will allow us to optimize the effectiveness of the drugs and avoid treating those patients that we know will not benefit.

In the case of metastatic colorectal cancer (mCRC), the turning point in the treatment within this precision medicine has been marked by the study of alterations in the RAS genes. But how does the RAS gene act in this disease? In fact, this gene was described more than 30 years ago associated with different types of tumors, but the importance of RAS is due to the fact that 10 years ago the study of this gene could be used as a marker to indicate a specific therapy for patients with metastatic colon cancer. This therapy is the use of antibodies against another gene called EGFR.

Those people who have mCRC should study the mutation of the alteration of this gene to determine whether they can receive this drug or not. Patients who have the mutation do not benefit; patients who do not have the mutation will benefit. Approximately 50 percent of patients would benefit if they do not have this RAS mutation, which means that in these cases anti-EGFR antibodies will dramatically improve patient survival.

How is the diagnosis of RAS made?

Precision medicine represents a revolution and a paradigm shift in how medicine is approached, in this case in the treatment of CCRm, based on the study of gene alterations. The main difference of precision medicine against traditional treatments against cancer, specifically chemotherapy, is that in metastatic colon cancer the diagnosis of RAS allows the use of biological drugs that are directed against specific molecules or factors within the tumor, while “classical chemotherapy is used indiscriminately, that is, all patients should be given the same treatment regardless of the type of tumor they have.

When selecting the type of treatment required by the patient with advanced disease, the oncologist will ask the laboratory to determine if there is such an alteration or not of RAS to make a decision. This initial check is also useful to determine the average cost required. To note, the cost of cancer treatment can sometimes be very large, requiring patients to seek funding sources from third parties like Family Money.

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