Colorectal Cancers

 

Colorectal cancer begins when healthy cells in the colon or rectal forms a mass
called a tumor.

There are 2 types of Colorectal Cancers:
1) Benign: This means the tumor grows in a specific area but does not spread.
2) Malignant- This tumor grows and spreads to the other parts of the body.

Types of cancer in the colon and rectum

• Adenocarcinomas are common colorectal cancer. These cancers start in cells that make mucus to lubricate the inside of the colon and rectum.
• Carcinoid tumors. These start from special hormone-making cells in the
  intestine.
• Gastrointestinal stromal tumors (GISTs) begins in the special cells of colon wall or digestive tract called the interstitial cells of Cajal.
• Lymphomas are cancers starting in lymph nodes or immune system cells.
• Sarcomas is although rare form of colon cancer but can start in blood vessels, muscle layers, or other connective tissues in the wall of the colon and rectum. 

Colorectal Cancer Risk Factors
There are 2 types of risk factors when it comes to Colon Rectal Cancer; the ones
you can change like Obesity, smoking, drinking, not physically active and the ones
you cannot change like being older etc.
Let us discuss some of these risk factors:

• A personal history or pattern of colorectal polyps or colorectal cancer: The risk of colorectal cancer increases if one has a history of adenomatous polyps
  (adenomas). This is especially true if the polyps are large, if there are many of them or if any of them show dysplasia.
• Previous inflammatory bowel disease: The risk of colon cancer increases with people having inflammatory bowel disease
  (IBD), ulcerative colitis or Crohn’s disease. IBD is a condition in which the colon is inflamed over a long period and develop
  dysplasia.
• A family history: People with a history of colorectal cancer in a first-degree relative like parents, sibling, or child are at increased risk.
• Having an inherited syndrome
  Lynch syndrome is commonly inherited syndromes linked with colorectal cancers which is hereditary non-polyposis colorectal cancer.

Symptoms and Signs
People with colorectal cancer may experience the following symptoms or signs such as:

• Diarrhea, constipation, or the bowel does not empty completely
• A change in bowel habits
• Blood in the stool (bright or red)
• Thin or Narrow Stools than normal
• Discomfort in the abdomen, frequent gas pains, bloating, fullness, and cramps
• Sudden Weight loss
• Fatigue or Constant tiredness
• Unexplained iron-deficiency anemia.

Diagnosis
Colonoscopy is the most common way of examining colorectal cancer.
In this, a Doctor uses a scope to examine the inside of your colon (colonoscopy). A
long and a flexible tube attached to a video camera and monitor to view your entire colon and rectum. If suspicious areas, the doctor can pass surgical tools through the tube to take tissue samples (biopsies) for analysis and remove polyps.

Radiology: Once the biopsy is confirmed, the doctor will then advise either a PETCT scan or a CT scan of thorax abdomen and elvis to stage the disease. In rectal cancers, additionally a MRI maybe done to assess the anal sphincters and the peri rectal region

Blood tests: tests like CEA and CA 19.9 are called tumour markers and they may aid in the diagnosis

Treatment Options
In cancer care, different types of doctors often work together that combines different types of treatments. All the specialists at Advanced Oncology Clinic meet together in what is called a multidisciplinary team (MDT) meeting to tailor the procedure to each patient.

To plan the ideal treatment for the patient all treatment decisions should consider factors such as:

• The patient’s health and other medical conditions
• Any Potential side effects of the treatment plan
• Any medications other than Cancer that the patient already takes

Below are explanations about each main type of colorectal cancer treatment.

Surgery
Surgery is the removal of the tumour and some surrounding healthy tissue during an operation wherein a part of the healthy colon or rectum and nearby lymph nodes are removed. 
Various new surgical techniques for removal of colorectal cancer include:

• Laparoscopic surgery With this technique, several viewing scopes are passed into the abdomen while a patient is under anesthesia. The incisions are smaller and the recovery time is often shorter than with standard colon surgery. Laparoscopic surgery is as effective as conventional colon surgery in removing cancer. 
• Robotic Surgery : In this the arms of the surgical robot are introduced into the patients abdomen and then the surgeon guides the arms to do the surgery. The robotic arms mimic the surgeons movements. The tissue trauma is the least and the recovery of the patient is very quick with robotic surgery. 

Radiation therapy
Radiation therapy is the use of high energy x-rays to destroy cancer cells. A
radiation therapy regimen, or schedule, usually consists of a specific number of
treatments given over a set period of time.
External-beam radiation therapy. External-beam radiation therapy uses a machine to deliver x-rays to where the cancer is located. Radiation treatment is usually given 5 days a week for 5 weeks.

When radiation therapy is used before surgery, it is called neoadjuvant therapy, It helps to shrink the tumor so that it is easier to remove. When it is used after surgery to destroy any remaining cancer cells it is called adjuvant radiation. 

Nowadays Short Course Radiation is also available which gets completed in 5 days

Systemic Therapy
Systemic therapy is the use of medication to destroy cancer cells. This type of medication is given through the bloodstream to reach cancer cells throughout the body. 
Common ways to give systemic therapies include an intravenous (IV) tube placed
into a vein using a needle or in a pill or capsule that is swallowed (orally).
The types of systemic therapies used for colorectal cancer include:
· Chemotherapy
· Targeted therapy
· Immunotherapy

Chemotherapy
Chemotherapy is the use of drugs to destroy cancer cells, usually by keeping the cancer cells from growing, dividing, and making more cells.
For some people with rectal cancer, the doctor will give chemotherapy and radiation therapy before surgery to reduce the size of a rectal tumor and reduce the chance of the cancer returning.

Targeted therapy 
Targeted therapy is a treatment that targets cancer’s specific genes, proteins, or the tissue environment that contributes to cancer growth and survival. This type of treatment blocks the growth and spread of cancer cells while limiting damage to healthy cells.
For colorectal cancer, the following targeted therapies may be options.
Anti-angiogenesis
Bevacizumab (Avastin)

Regorafenib (Stivarga).

Ziv-aflibercept (Zaltrap)

Ramucirumab (Cyramza)

Epidermal growth factor receptor (EGFR) inhibitors

Cetuximab (Erbitux)

Panitumumab (Vectibix)

Immunotherapy 

Immunotherapy also called biologic therapy, is designed to boost the body's natural defences to fight cancer. It uses materials made either by the body or in a laboratory to improve, target, or restore immune system function.

Here are different types of immunotherapy used to treat colorectal cancer. 
·    Pembrolizumab (Keytruda)
·    Nivolumab (Opdivo)
·    Nivolumab and ipilimumab (Yervoy) combination