Colorectal Cancer - Types, Symptoms, Causes and Treatment

Colorectal cancer is among the top 5 most frequent cancer cases found worldwide. Above 40,000 Indians have been detected with colorectal cancer in 2021, as of March. Among them, most are male patients. Symptoms of such cancer are difficult to identify. Hence, most cases go undiagnosed.

Here we will discuss the causes, symptoms, and types to enhance your awareness and go for period screening.

Cancer or malignant growth of cells in the large intestine is colorectal cancer. However, depending on the placement of cancer cells in a specific part of the large intestine, it is identified as bowel, colon, or rectal cancer. It affects the colon and rectum, which form the lower part of the digestive system. These cancer symptoms are hard to diagnose before it enters the second stage.

There are 2 types of risk factors -

1. Fixed Factors

These are factors beyond your control -

• Age 50 years or more
• Genetic syndromes like familial adenomatous polyposis.
• Colon polyps.
• Bowel diseases

2. Modifiable Factors

You may adopt a healthy lifestyle and induce colorectal cancer prevention. Some modifiable risk factors are -

• Sedentary lifestyle
• Overeating
• Obesity
• Excessive smoking
• Drinking
• Prolonged diabetes
• Consuming processed meals for a long time

Depending on the area of malignant cells’ formation, there are different types of colorectal cancer. These are -

• Adenocarcinomas – 90% of colorectal cancer is of this type. It causes malignancy in the cell that prepares mucus in rectum.
• Sarcomas – Occurs in soft tissues or muscles in colon.
• Lymphomas – Occurs in the lymph node of colon.
• Carcinoids – Occurs in hormone making cells of large intestine.

Colorectal cancer symptoms are as follows -

• Cramping pain in the abdomen
• Bloating
• Gas
• Irritable bowel syndrome
• Urges to defecate even after passing stool
• Narrow or loose stool
• Blood in stool
• Change in consistency of the stool
• Anaemia
• Fatigue
• Unintentional weight loss
• Constipation
• Often diarrhoea

Signs and symptoms of colorectal cancer are very hard to identify in the early stage. However, those stated above notably arise in progressing stage.

One of the most important colorectal cancer causes is genetic mutation. The mutation in the gene may cause benign growth or polyps. The cell grows abnormally and may spread to another part of the body through the lymph system and blood. Some of the most common reasons are:

• Polyps – Two types of polyps responsible for colorectal cancer are adenomas and hyperplastic. 
• Genetic mutation – For genetic predisposition from family or relatives, you may inherit colorectal cancer. Some common risk factors are familial adenomatous polyposis, Gardner syndrome, Lynch syndrome, juvenile polyposis syndrome, peutz–jeghers syndrome, turcot syndrome.
• Traits - Age, food habits, lifestyle are some other most important factors responsible for cancer.
• Health conditions – Prolonged diabetics, radiation therapy, inflammatory bowel diseases, ulcerative colitis, and acromegaly are responsible for colorectal cancer.

Colorectal cancer treatment is dependent on the patient's health status, stage, age, physical strength, compliance affordability, and other factors. The main aim is to prevent further spread, remove cancerous growth or cells, and give the patient at the earliest.

Some of the disciplines of treatment are -

1. Surgery

The main objective of surgery is to remove the cancerous part of the colon or the entire colon with nearby tissues affected. It is generally done in final colorectal cancer staging to protect from further spreading. In some cases, a stoma is created for the passage of waste products. The stoma is a surgical opening inside the intestine attached to a bag to store the stool. It substantiates the lower part of the colon.

Types of surgery done are -

• Colostomy – Full or partial removal of colon and attaching stoma to it.
• Endoscopy – Through a localised part camera, light and scissors are inserted inside the colon, and some cancerous tissues are taken out.
• Laparoscopy – Through small incisions, removes polyps or growths in the colon segment.
• Palliative surgery – In the case of untreatable or advanced cancer stages, minor blockages are removed to relieve the patient from pain, bleeding, and other physical conditions due to colorectal cancer.

2. Radiation Therapy

According to the colorectal cancer treatment guidelines, a doctor implants a seed of heavy radioactive material like radium near the cancerous site. It emits continuous radiation like X-rays, Gamma-ray, etc., to the cancerous cells or tumours to shrink and kill them.

Doctor generally administers it during the early signs of colorectal cancer.

3. Chemo Therapy

Based on what are the symptoms of colorectal cancer, a doctor advises chemotherapy. In this process, medicines are given, which stops the growth of the cancerous cells by binding with the DNA proteins. The medicine can travel to any part of the body so it can rapidly control cancerous cells spreading out in any part of the body.

This mode of colorectal cancer treatment cost in India is higher as it is done throughout a prolonged period and induces certain side effects. An interval is given in between two doses and patients are hospitalised to help them recover from the side effects.

Some common chemotherapy drugs are -

• Capecitabine (Xeloda)
• Oxaliplatin (Eloxatin)
• Irinotecan (Camptosar)
• Capecitabine (Xeloda)
• Fluorouracil

4. Drug Therapy

Some drugs are approved by the Food and Drug Administration (FDA) as immunotherapy and targeted therapies -

• Ramucirumab (Cyramza)
• Ziv-Aflibercept (Zaltrap)
• Panitumumab (Vectibix)
• Pembrolizumab (Keytruda)
• Nivolumab (Opdivo)
• Ipilimumab (Yervoy)
• Bevacizumab (Avastin)
• Cetuximab (Erbitux)
• Regorafenib (Stivarga)

It cannot be prevented if the cause is a genetic factor; however, lifestyle disorders, overweight, overeating, avoiding having processed meat, smoking and drinking addictions can be controlled to prevent colorectal cancer.

Colorectal cancer is diagnosed by colonoscopy, double-contrast barium enema, and other tests. Although the symptoms in the initial stage are not obvious, warning signs are there. If you have any family history of such disease or have any warning signs, you should consult a doctor for screening. Precaution is better than cure. Therefore, you should be cautious and lead a healthy life.