COLON CANCER- Causes, Treatment and Medications

In the human body colon is the last segment of the digestive tract. Beginning in the large intestine, colon cancer is generally known to affect older people. It starts as a growth on the inner lining of the rectum as polyps and transforms into cancer over time. However, all polyps don’t turn cancerous; it depends on the type. 

Usually, adenomatous polyps, hyperplastic & inflammatory polyps, and sessile serrated polyps are known to become cancerous. Other than that, if the polyp is larger than 1 cm, if more than three polyps have been diagnosed, and if pre-cancerous conditions such as dysplasia are noticed after the removal of the polyps, there is a chance of cancer too. 

Causes of colon cancer

So far, there are no sure-fire causes of colon cancer, but certain risk factors include an unhealthy diet consisting of large amounts of processed food, red meat, and sugary drinks, tobacco smoking, and overuse of alcohol. There are also cases that are hereditary. A family history of colon cancer can be counted as a huge risk factor. 

Symptoms of colon cancer

If you notice the following symptoms, consult your doctor immediately:

• A noticeable change in bowel movements such as diarrhea and constipation

• Change in stool consistency

• Abdominal pain, cramps, and gas

• Weakness and fatigue

• Unusual weight loss

Types of treatment for Colon Cancer

• Surgery:

Depending on the stage of cancer, patients can opt for this treatment. It is done on an empty and clean colon, and the patient will also have to follow a special diet before surgery. The types of surgical procedures are polypectomy, local excision, colectomy, colostomy, ileostomy, and diverting colostomy. 

• Radiation therapy:

In this case, radiation therapy is not quite common. However, it can be recommended before and after surgery to shrink the tumor and increase the chances of success for the surgical procedure. Not only that, but radiation is also given with chemo and in a metastatic case where cancer has spread to other parts of the body like lungs, bones, and brain.

• Chemotherapy:

Here, anti-cancer drugs are used to kill the cancer cells in the body or slow down their rapid growth. It can also be given after or before surgery and sometimes combined with radiation therapy for better results. Chemotherapy is conducted in cycles, each of them being 2 to 3 weeks long. 

• Targeted therapy:

Targeted therapy also uses drugs that reach the bloodstream and target the cancer cells to destroy them. It is prescribed if chemotherapy isn’t working or if cancer has a specific genetic mutation like EGFR or BRAF that can be targeted. 

• Immunotherapy:

In this case, medicines boost the immune system of the patient to recognize the cancer cells and fight them. These drugs are also called checkpoint inhibitors that can identify cancer cells by the over-expression of certain proteins.

Medications used to treat Colon Cancer:

• Capecitabine:

This drug is given as a palliative treatment for metastatic colon cancer or as adjuvant chemotherapy. It has been classified as an anti-metabolite and is cytotoxic in nature. The medicine gets converted to Fluorouracil in the body to act upon the tumor cells. For metastatic colorectal cancer, Fluoropyrimidine Capecitabine is given as first-line therapy. Capecitabine 500 mg is taken as a pill by mouth within 30 minutes of a meal with water in the exact dose prescribed by the doctor. 

• Fluorouracil:

5-FU is prescribed as chemotherapy for colon cancer. Fluorouracil injection is given intravenously with Leucovorin to make it more effective. In fact, this medicine has been the first choice of doctors for treating colorectal cancer over the years. Its objective is to stop the cancer cells from forming their DNA that will ultimately destroy them. This drug belongs to the family of anti-metabolites as well. Also referred to as a pyrimidine analog, Fluorouracil is used as an antineoplastic agent. It is also available as a topical, but Fluorouracil cream is used for treating skin cancers caused by sunburns and UV rays.

• Leucovorin:

Better known as Folinic acid, Leucovorin is usually given with Fluorouracil for colon cancer. It is also regarded as the most commonly prescribed chemotherapies for colorectal cancer. Therapy is conducted in cycles, and each cycle ranges from one to four weeks. Leucovorin 15mg is administered via an intravenous injection that takes place for about 3 minutes, followed by the Fluorouracil injection.

• Oxaliplatin:

This medication is also prescribed in combination with other anti-cancer drugs like Folinic acid and Fluorouracil for advanced colon cancer. Oxaliplatin is also given as an injection into the vein. It is classified as a third-generation novel platinum compound that has shown significant improvement in the disease progression rate of colon and rectal cancer. Combination medicines are given as a 2-day treatment initially. After that, it is given every 2 weeks until the body starts responding to treatment. 

• Regorafenib:

It is an oral multi-kinase inhibitor that is prescribed for its anti-angiogenic activities to target the VEGFR2-TIE2 tyrosine kinase. Regorafenib is given as a targeted therapy regimen for refractory colon cancer. In clinical trials, Regorafenib 40 mg is shown to have the most beneficial toxicity to deal with advanced cancer cases. 

• Irinotecan:

Given in combination with 5-FU or Oxaliplatin, Irinotecan is a key anti-cancer drug used for the treatment of metastatic colorectal cancer. Its main objective is to prevent the relegation o the DNA strand by inhibiting the action of topoisomerase so that the cancer cell growth is reduced.

• Lonsurf:

It is prescribed to adults with colorectal cancer who have previously received therapy with Oxaliplatin, Fluoropyrimidine, and Irinotecan and aren’t responding to standard chemotherapy anymore. 

Conclusion

Colon cancer is categorized as the third most common cancer type in men and women of the United States. It is highly treatable and curable in the initial stages by surgery or chemotherapy. However, the case becomes complicated when there is a relapse after surgery that acts as the ultimate cause of death in this case. The last stage of colon cancer has a low survival rate of only 14%. With the new treatment methods and drugs under development, there is hope for an improvement in the number.