Colorectal Cancer Blood Tests

Colorectal Cancer: What Is It?

Colorectal cancer occurs in the tissues of the colon or rectum, which are part of the digestive system.

• Colon: The colon is the first and longest segment of the big intestine. It takes in certain nutrients and water from food and turns the residual waste materials into feces.

• Rectum: The lowest portion of the big intestine is called the rectum. The body stores stool there.

Colon cancer is the name given to cancer that starts in the colon, and rectal cancer is the name given to cancer that starts in the rectum. Colorectal cancer is another term for cancer that can affect either of these organs.

Colon cancer is diagnosed in stages:

1. Stage 0: In situ carcinoma.

2. Stage 1.

3. Stage 2.

4. Stage 3.

5. Stage 4.

Recurrence has been reported after receiving treatment.

Why Does Colorectal Cancer Occur?

Genetic material (DNA) alterations cause colorectal cancer. Variants or mutations are other terms for these alterations. The precise source of the genetic alterations that cause colorectal cancer is frequently unknown and occurs during an individual's lifetime. However, some genetic abnormalities that increase the risk of colorectal cancer are inherited, meaning that one has them from birth. Lifestyle and surroundings, in addition to genetics, can influence the risk of colorectal cancer.

Who Is Most Vulnerable to Colon Cancer?

Although colorectal cancer can strike anyone, the following variables increase the risk of getting it:

• Getting Older: As one becomes older, the risk of colorectal cancer rises.

• Has a family or personal history of colorectal cancer.

• Possessing adenomas in the past. Adenomas are colorectal polyps or growths that measure one centimeter or more and seem abnormal under a microscope. Adenomas do not always result in cancer, but they can occasionally do so over time.

• Possessing a genetic syndrome, such as Lynch syndrome (hereditary non-polyposis colorectal cancer) or familial adenomatous polyposis (FAP).

• Having Crohn's disease or chronic ulcerative colitis for a minimum of eight years.

• Consuming alcohol over three times a day.

• Cigarette smoking.

• Being Black: Compared to people of other races, Black people are more likely to develop colon cancer and die from it.

• Being overweight.

Who Needs to Have a Colorectal Cancer Screening?

Tests for colorectal cancer should be performed because the disease may not show signs at first. Screening tests search for illness indicators before the onset of symptoms. They can aid in early cancer detection when treatment may be simpler. Most experts advise beginning screenings at age 45 and continuing them until age 75. Individuals at high risk or over 75 years old should discuss with their healthcare providers the frequency and kind of appropriate testing for them. Various stool tests and procedures, including colonoscopies and flexible sigmoidoscopies, are among the test kinds.

How Is Colorectal Cancer Diagnosed?

There are multiple approaches to CRC screening based on US recommendations. Flexible sigmoidoscopy.

• Colonoscopy.

• Biopsy.

• Fecal Occult Blood Test (FOBT): A stool-based test is a noninvasive method; the most popular one is the fecal occult blood test (FOBT), which looks for blood in the stool.

• Understanding the biology of colorectal cancer (CRC) has advanced, and molecular abnormality-based screening technologies have emerged as novel avenues for investigation.

What Are the Blood Tests Done to Diagnose Colorectal Cancer?

Vascular invasion is necessary for the markers that the tumor releases to be found in the blood. Lesions that are precancerous and do not yet have vascular invasion should have very little blood entering the bloodstream. However, when the cancer stage advances and the degree of vascular invasion increases, so does the amount of marker found in blood. Blood tests are simpler to use and adhere to but may be less sensitive in identifying lesions in their early stages than stool-based tests.

Blood Test:

• A glycoprotein called carcinoembryonic antigen (CEA) is involved in the cell attachment process.

• Serum CEA had sensitivity in samples of CRC patients, demonstrating its usefulness as a diagnostic marker.

• A few scientists demonstrated this. Cancer antigen 19-9 (CA 19-9), a cancer marker more frequently employed to identify pancreatic cancer, demonstrated a sensitivity of 36 percent and a specificity of 97 percent for colorectal cancer (CRC) in the same population.

• Serum CEA level is still often used to track post-operative recurrence. However, it is rarely utilized as a disease predictor. Nuclear matrix proteins are colon cancer-specific antigen (CCSA)-3 and CCSA-4.

Micro-RNA and Messenger RNA in Blood:

• Blood-based mRNA has not been widely used as a CRC biomarker in research.

• KIAA1199 was identified as a CRC biomarker using oligonucleotide microarray research on colorectal tissues. However, its exact role is yet unknown. The serum KIAA1199 mRNA level showed a sensitivity of 74 percent for CRC and adenoma and a specificity of 66 percent.

• Because plasma miRNAs could be robustly quantified and remain highly stable in the environment, more research has concentrated on them.

• A few scientists showed the value of plasma-based miRNA as CRC biomarkers. They found that plasma miR-92a, a candidate found using miRNA array profiling, could distinguish between CRC patients and controls with an 89 % sensitivity and 70 % specificity. Interestingly, the plasma miR-92a level dramatically decreased when the tumor was removed, indicating that the marker was probably generated from the colorectal lesions.

• Since then, additional miRNA candidates, including miR-29a, miR-221, miR-21, U2 small nuclear RNA (RNU2-1), miR-601, and miR-760, have been reported. It was discovered that RNU2-1, a marker for pancreatic ductal adenocarcinoma (PDAC) and colorectal cancer (CRC), has a 97.7 percent sensitivity and 90.6 % specificity in identifying PDAC and CRC.

Blood DNA:

• Compared to other plasma-based markers, the evaluation of plasma DNA has proven more robust due to the documented mutation and methylation characteristics found in the adenoma-carcinoma sequence.

• According to a few scientists, the mutant APC fragment has a sensitivity of 63 percent for identifying Dukes A and B stage patients (n=16) and 100 percent for identifying Dukes D stage patients (n=6). However, the test's ability to identify advanced adenoma remained lacking.

• Among plasma DNA markers, hypermethylated Septin-9 has been examined the most. According to several studies, its sensitivity to colorectal cancer (CRC) ranged from 52 percent to 73 percent, with specificities between 84 percent and 91 percent; its sensitivity to advanced adenoma was less than 20 percent. Currently, the only commercially available plasma DNA test designed for CRC detection is the Septin-9 test.

Blood Fatty Acid:

• GTA-446 is a polyunsaturated fatty acid with a long chain found in the digestive tract. Its serum level can be determined using mass spectrometry.

• Patients with CRC were shown to have lower serum GTA-446 levels. A few scientists demonstrated that, with a test specificity of 90 percent. It was suggested that a lower level of serum GTA-446 indicated a weakened defense against aberrant cell proliferation and persistent inflammation.

How Is Colorectal Cancer Treated?

There are many methods of treatment for patients with colon cancer.

• There are seven common forms of treatment used:

• Surgery: For all stages of colon cancer, surgery (removing the cancer through an operation) is the most popular form of treatment. A surgeon may use one of the following procedures to remove the cancer:

  • Local incision.

  • Colonectomy combined with anastomosis.

  • Colon resection via a colostomy

• Radiofrequency Disintegration: Radiofrequency ablation involves using a specialized probe with small electrodes to kill cancer cells. Local anesthesia is unnecessary when the probe is put straight through the skin. In other situations, an abdominal incision is used to introduce the probe. General anesthesia is used at the hospital for this procedure.

• Cryosurgery: In cryosurgery, an instrument freezes and kills aberrant tissue. Another name for this kind of care is cryotherapy.

• Chemotherapy: Chemotherapy is a type of cancer treatment in which medications kill or inhibit the growth of cancerous cells. Chemotherapy can reach cancer cells all over the body, whether it is administered orally or through an injection into a vein or muscle (a procedure known as "systemic chemotherapy"). Chemotherapy concentrates its effects on cancer cells in the locations it is applied directly to, such as the abdomen, an organ, or the cerebrospinal fluid (regional chemotherapy).

• Radiation Treatment: High-energy X-rays and other radiation therapies are used in radiation therapy to either kill or stop the growth of cancer cells. Two varieties of radiation therapy exist:

  • Equipment outside the body is used in external radiation therapy to direct radiation onto the cancerous part of the body.

  • When administering internal radiation therapy, radioactive materials enclosed in needles, seeds, wires, or catheters are inserted into or close to the malignancy.

• Targeted Treatment: Drugs or other substances are used in targeted therapy to target and destroy particular cancer cells. Generally, targeted therapies are less harmful to normal cells than radiation or chemotherapy.

• Immunotherapy: A treatment called immunotherapy uses the patient's immune system to combat cancer. Substances synthesized in a lab or produced by the body can strengthen, direct, or restore the body's natural defenses against cancer. This is a kind of biological therapy for cancer.

• Clinical trials are being used to assess new therapeutic approaches.

• There could be adverse effects from colon cancer treatment.

• Individuals may consider participating in a clinical trial.

• Clinical trials can be enrolled by patients before, during, or after the initiation of cancer treatment.

• Additional testing could be required.

Conclusion

The rectum or colon is where colorectal cancer first appears. These tumors may also be referred to as rectal or colon cancer, depending on where they originate. Because they share many characteristics, rectal and colon cancer are frequently combined. Globally, colorectal cancer (CRC) is the third most frequent type of cancer. There is a significant clinical benefit to screening asymptomatic persons because many CRC patients were discovered at advanced stages of the disease. The majority of CRC starts in a detectable early stage. Testing molecular aberrations in stool and blood offers novel screening procedures that are noninvasive, sensitive, and more cost-effective than standard structural inspections, thanks to the growing understanding of the biology of colorectal cancer (CRC) and precancerous lesions.