Introduction

Colorectal cancer (CRC) is the most common neoplasm in the digestive tract, constituting 9 to 10% of all cancers in the world. It is considered to be multicausal, as it encompasses intrinsic factors of the host such as genetic mutations, hormonal mutations and immunological conditions; in addition to external factors such as unhealthy diets, alcohol consumption, obesity, sedentary lifestyle, smoking and environmental exposure to carcinogens. The clinical manifestations are not very specific, which is why the diagnosis is focused on risk groups related to age and proven family history.

 

 

Objective: Identify the diagnostic aids that we can offer from the Clinical Laboratory as a contribution to the early detection of colon cancer, as well as make a call to action, the commitment to do something from our roles to help in the fight against cancer.

 

The most frequent types of cancer in Colombia, according to the data analyzed for cancer in High Cost Accounts, the 5 types of cancer with the highest incidence in the country in the adult population during the study period were defined, in order they are: breast cancer with 29.3%, cervical cancer with 7.1%, colon and rectum with 6.4%, stomach 4.3% and prostate 2.6%

 

In this article we will focus on colorectal cancer, since in Colombia each year there are approximately 5,000 new cases of this type of cancer, being the third cause of mortality among women and the fourth in men.

 

90% of cases can be treated successfully if they are diagnosed in time, if we focus on knowing incidence data, knowing symptoms and risk factors.

 

 

Colorectal cancer generally begins with polyps or growth in the mucosa of the intestine, producing malignant cells in the innermost layer of said organ and an abnormal increase in the tissue usually occurs between the ages of 50 and 80. However, lifestyle, diet, environmental exposure, sedentary lifestyle and obesity are factors that have influenced the appearance of this disease.in increasingly younger patients. 

 

Although this pathology can arise from genetic causes (family history of colon cancer), these cases only account for 5% of new diagnosed patients. The majority suffer from sporadic cancer, that is, they had no history of this disease and are exposed to risk factors. 

 

Talking about prevention and detection implies thinking about two conditions that must be differentiated, one thing is to carry out studies for prevention and another is to carry out studies of the patients’ symptoms, among which are mainly unknown anemia or due to digestive bleeding, unexplained weight loss, decrease and persistent alteration in the habit and size of bowel movements, intense pain or frequent abdominal distension, presence of blood in the fecal matter and sensation of evacuation. dissatisfied.

If from the clinical laboratory, we work hand in hand with the medical team, we can make a great team fighting against colorectal cancer (CRC).

 

Let’s start talking about the algorithm to classify the risk of colorectal cancer:

The Ministry of Health has developed a Clinical Practice Guide (CPG) for the early detection, diagnosis, treatment, monitoring and rehabilitation of patients diagnosed with colon and rectal cancer. They present the algorithm to classify the risk of CRC, presenting the contribution from the clinical laboratory, providing the SOMF (invasive blood in fecal matter) examination every two years to people between 50 and 75 years old, as a non-invasive technique and/or complementing it in such a case that it is positive with colonoscopy as a standard but invasive Gold technique, with monitoring every 10 years.

 

Currently there are the following methods, these with different levels of invasion:

1. SOMF Detection of occult blood, which passes in such small amounts that it can only be detected by chemicals used in a fecal occult blood test. 
2. Colonoscopy: Optical colonoscopy involves direct visualization of the colonic mucosa from the cecum to the rectum with a flexible endoscope. Insufflation, irrigation, and suction facilitate careful inspection of the mucosa. Colonoscopy allows both the detection and removal of polyps, which can be sent for histopathological examination. Colonoscopy has traditionally been considered the gold standard for CRC detection, however, flaws have been found, it is less effective for reduct proximal CRCs compared to distal ones due to various factors such as inadequate bowel preparation and/or incomplete colonoscopy, that is, it depends on the operator. 
3. Sigmoidoscopy:  It is a procedure used to see the inside of the sigmoid colon and rectum. The sigmoid colon is the area of the large intestine closest to the rectum.
4. Barium enema is an imaging test that uses x-rays to look at your lower gastrointestinal (GI) tract. Your lower gastrointestinal tract includes the large intestine (colon) and rectum.

 

The diagnostic aids that we can provide from the laboratory are in different modalities, among these tests we have:

 

Let’s review what concerns us in the Clinical Laboratory. To detect occult blood in feces there are several methodologies:

 

• Test Guayaco. It is the oldest, best known and cheapest method for detecting SOMF, however, it has restrictions such as “not consuming red meat, broccoli, beets or uncooked radishes for three days before the exam. Some medications can alter the result of the test, such as: vitamin C and non-steroidal anti-inflammatories. Its interpretation is subjective, the sampling is not standardized and many times the person who processes it is the Laboratory assistant.
• FIT: Immunological Methods (rapid tests): The cassette sampling technique is simpler and easier to collect compared to guaiac. Only one or two fecal samples are required and no dietary or medication restrictions are required prior to testing. Improves accuracy in CRC detection. A disadvantage of FIT is its more expensive cost compared to guaiac. Although FIT is easier to collect, its sensitivity decreases with any delay in sample shipping or processing. Additionally, similar to other non-invasive tests, if the test is positive, a follow-up colonoscopy would be needed.
• Fecal Hemoglobin Immunological Test by Turbidimetry (Fit): Another option we have are immunological tests by turbidimetry, they are methods that are carried out on fully automated equipment, it works with a calibration curve, it is controlled every day, therefore we will have the test monitored. It is very specific for lower digestive bleeding, it does not require dietary restriction and it has no interference.ias with medications their results are quantitative, facilitating the interpretation of the operator and the medical staff. Additionally, the sample is standardized in a collection device.
• Finally, we present another much more specific and sophisticated option for SOMF detection, the multi-target stool DNA test that uses specific biomarkers to guarantee the highest levels of sensitivity to determine the presence of some mutations. In a study carried out, it was shown to be more sensitive than the FIT test, detecting 21% more precancerous lesions

 

The review of this topic is an invitation to participate more in promotion and prevention programs as health professionals, to work on screening to detect colorectal cancer with the tests that exist on the market. Having this knowledge we can propose that we work on these programs and together we can reduce mortality from cancer and high cost bills. 

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