Metastatic Colorectal Cancer- Causes, Risk Factors, Clinical Factors, Diagnosis and Treatment

Introduction:

When seen as a diagnosis in any of your loved ones' reports, metastatic colon cancer can destroy the happiness and peace of a family. Unfortunately, as deadly as it might sound to you, cancer has become very common among its population now. The good news is that early diagnosis and appropriate treatments can treat cancer to some extent. Colorectal cancers are cancers of the colon (large intestine) or rectum. When the cancer cells travel from the origin site of the tumor to other parts of the body, the process is called metastasis. In colorectal cancer, the cancer cells travel from the colon or rectum to other organs like the lungs, liver, abdomen, or brain through the bloodstream or lymphatic system.

What Is Metastatic Colorectal Cancer?

Colorectal cancers are one of the common cancers affecting the human population. This cancer is staged from stage zero, the earliest stage of colorectal cancer, to stage four, the advanced severe metastasized stage of colorectal cancer. The cancer cells are spread from the initial site of the tumor to other organs and lymph nodes. Metastasized tumors are a challenge to general physicians and oncologists as metastasized tumors are very hard to control. However, recent advances in medical sciences have shown improvement in the affected survival rates.

What Causes Colorectal Cancer? How Does It Progress?

The exact cause of colorectal cancers is unknown at present. In general, specific changes (mutations) in the genes of the healthy cells are responsible for developing tumors in the body. In cases of colorectal cancers, the DNA (deoxyribonucleic acid) of the healthy cells of the colon is altered or damaged, which damages the general normal functioning of the cells, where the DNA promotes abnormal cell production that forms tumors in the colon or rectum. Initially, polyps can be found in the walls of the colon, which are benign. Later, these polyps get converted into cancer over several years, and they invade the bloodstream and lymphatic system through which the cancer cells invade other vital organs and lymph nodes. Colorectal cancer often metastasizes to the liver, peritoneum, and lungs. It can also metastasize to other organs like kidneys, brain, heart, etc.

Who Is at a Greater Risk of Developing Metastatic Colorectal Cancer?

Following are some of the risk factors of colorectal cancer:

1. Age: Older people are more commonly affected by colorectal cancer. People above 50 years are at a higher risk of developing colon or rectum cancer.

2. Racial Predilection: African-Asian people are more commonly affected by colorectal cancer.

3. Sedentary Lifestyle: People leading a sedentary lifestyle with minimum to no physical activities are at a higher risk of getting colorectal cancer and getting other cardiovascular problems.

4. Polyps: Colon polyps are benign growths seen on the colon's inner lining. These polyps can develop into tumors over the years if not treated early.

5. Family History: People with familial history of colorectal cancer are at a higher risk.

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6. Poor Dietary Habits: Poor western fast-food diet is becoming common among the population. These fast-food diets are filled with fats and are deficient in fiber content. A high-fat, low-fiber diet is one of the common risk factors for colorectal cancer.

7. Diabetes: People with uncontrolled diabetes can develop colorectal cancer.

8. Obesity: Unmanaged overweight people leading a sedentary lifestyle with poor dietary habits are at a higher risk of getting colorectal cancer.

9. Smoking Habits: Smoking cigarettes or tobacco can cause cancers like colorectal cancer and oral cavity cancers.

10. Excessive Drinking: Excessive alcohol intake can increase the risk of developing colorectal cancer.

11. Radiation: Radiation therapy that are directed to the abdomen to treat and prevent the recurrence of tumors in the abdomen can cause complications like colon cancer.

What Are the Signs and Symptoms of Colorectal Cancer?

People affected by colorectal cancers do not usually show any symptoms during the initial stages. The signs and symptoms typically develop during the later stages of cancer after metastasis occurs. Below are some of the common signs and symptoms associated with colorectal cancer,

• Altered bowel movements like constipation or diarrhea last for more than a few weeks.

• Narrow stools.

• Blood in the stool or the stool appears to be tarry black or can be maroon in color due to the presence of blood in it.

• Feeling of fullness after bowel movements.

• Rectal bleeding.

• Abdominal discomfort.

• Weight loss without trying.

• Fatigue.

• Anemia.

Some of the features mentioned above can also be seen in people with hemorrhoids or IBS (irritable bowel syndrome), common harmless gastrointestinal problems; therefore, proper diagnosis is mandatory. When colorectal cancers are metastasized to other organs of the body, specific symptoms develop depending upon the spread site.

• If metastatic colorectal cancer spreads to the liver, the person involved shows abdominal swelling or jaundice symptoms.

• If the tumor affects the brain, the person presents with headaches, dizziness, or seizures.

• When lungs are concerned, the affected person experiences breathing difficulties.

• If bones are involved, the person experiences frequent fractures and bone pain.

How to Diagnose Metastatic Colorectal Cancer?

Most cases of metastatic colorectal cancers are diagnosed after metastasis happens, as this cancer does not show any significant symptoms during its initial stages. However, in some, colorectal cancers can be diagnosed during the initial stages during regular checkups.

• The most common method of diagnosing colorectal cancer is through colonoscopy. In this method, a small camera fitted to a narrow extension is inserted into the colon to view the inner surfaces of the colon where polyps (benign growths which can later turn into malignant tumors) or malignant tumors are detected.

• A biopsy helps to check where the tissue growths are assessed to analyze if they are benign or malignant. A biopsy can also help evaluate the tumors acquired from other body regions to check if they are metastatic tumors with another primary tumor.

• CT (computed tomography) Scan: CT scans help diagnose the spread of the tumor to other sites in the body like the liver, brain, kidneys, etc.

• Ultrasound: Ultrasound is performed to detect metastasis of the tumor to the liver. It can also be used as a guide while performing biopsies.

• X-ray: X-rays can be used to see if the tumor metastasized to the lungs and help detect bone cancers.

How to Treat Colorectal Cancer?

Depending on your metastatic colorectal cancer's stage, severity, and location, your oncologist plans your treatment. Staging of the tumor, palliative chemoradiotherapy and other palliative care options such as enteral stenting, colostomy, pain relief, and proper dietary couselling and treatment are necessary. Besides this, a multidisciplinary team involvement is the key for proper management of the metastatic colorectal cancer, which includes a gastroenterologist, general surgeon, palliative care specialist, pain management team, dietician, and a psychologist or psychiatrist. The main aim of treatment is to relieve the patients from symptoms associated with cancer and prolong the individual's lifespan.

• Metastatic cancers are rarely curable, and in rare cases, surgical removal of all the metastatic tumors from the other sites can treat this cancer.

• Surgical interventions are required to remove the blockage of the colon.

• Symptomatic treatments where your doctor will provide medications to relieve symptoms like nausea, vomiting, etc.

• Chemotherapy and radiation therapy showed many improvements in the medical history in shrinking and preventing the recurrence of tumors.

• Certain targeted therapies are also involved in treating metastatic colorectal cancer.

Conclusion:

Metastatic colorectal is not impossible to cure. Recent advances in medicine and current therapies have shown increased survival rates among individuals with metastatic colorectal tumors. As much as we give importance to treating this cancer, the individuals affected and the family members of the affected individuals should undergo proper psychological help from the professionals to face this obstacle, and professional support can improve the mental wellbeing of the affected, which will enhance the quality of life. Proper diagnosis and good quality treatments can improve the lifespan and help treat the condition.