Doctors can do several tests and examination to check or to diagnose cancer. They also perform tests to find out whether cancer has not spread to other parts of the body. The spread of cancer to other body parts as well from it has started is called metastasis.

For several kinds of cancer, doctors generally choose biopsy tests in which they take a small part of the affected cells or tissue to the laboratory to examine it.

The doctor keeps the following consideration while choosing the test or examination to diagnose colon cancer like

The type of cancer to be suspected.
On the basis Symptoms or signs
On the basis of age and general health of the patient
History related to other medical conditions
Genes and family medical issues.

Otherwise, to test colon cancer doctors can perform several tests like

Colonoscopy

Colonoscopy is the screening method in which doctors can look inside the entire rectum and colon. The patient is sedated at the time of the colonoscopy procedure. Colonoscopist is the doctor who does colonoscopy. If the cancer is found in colonoscopy, then doctor performs more tests to find out if cancer has not spread to some other parts of the body front its origin point.

Biopsy

In small biopsy amount of affected cells or tissue is removed and doctors take it to their laboratories to check the tissue under a microscope. The biopsy is a full proof test and gives more amount of assurance as compared to other tests. The pathologist is a doctor who is an expert in laboratory examination or in evaluating cells, tissues, and organs to diagnose disease. A needle can penetrate inside to removes tissue through the skin or biopsy can be performed during a colonoscopy, or it is done on any tissue that is removed during surgery.

Molecular testing of the tumour.

Molecular testing of the tumour is done to find out other specifications like to identify specific proteins, genes, and other factors unique to the tumour. Result of molecular testing of the tumour helps to identify the other tests that need to be performed.

Blood test

Through bleeding, Colon cancer often reaches to large intestine or rectum, and people with colon cancer became anaemic. With the blood test, the doctor will be able to test the red blood cells, which can indicate that bleeding may be occurring or not.

Another blood test is done to find carcinoembryonic antigen means a blood test detects the levels of a protein. If the level of carcinoembryonic antigen test is high, that means the cancer is spread to the other parts of the body too. Carcinoembryonic antigen test is not useful as a screening test and most often used to monitor colorectal cancer in patients who are already undergoing the treatment.

Computed tomography (CT or CAT) scan.

In Computed tomography (CT or CAT) scan with the help of an x-ray, a picture is taken of the inside of the body. The computer then combined the taken 3-dimensional pictures to check if there any abnormality or any tumours. Computed tomography or CT scan is also used to measure the size of the tumour. In a few cases, contrast medium, a kind of dye is injected into the patient’s vein or given as a pill to identify the minute details.

Magnetic resonance imaging (MRI)

Instead of x rays, magnetic fields are used in Magnetic resonance imaging (MRI) to extract the details of the tumour. Magnetic resonance imaging (MRI) used to figure out the tumour size. Magnetic resonance imaging (MRI) also special dye like that in Computed tomography (CT or CAT) is injected before the scan to create a clearer picture. Magnetic resonance imaging (MRI) is considered to be one of the best ways to figure out the size and exact location of the tumour.

Ultrasound

Sound waves are used in ultrasound. Sound waves are used to create a clear picture of internal organs and to find out whether cancer has propagated to other body parts too. However, ultrasound still cannot provide a clear picture of whether cancer has spread to nearby lymph nodes or beyond the pelvis or not. Ultrasound can also detect liver as well but not as accurate as a CT Scan and MRI.

Chest x-ray

In chest x-ray, a small kind of radiation is used to see the picture inside the body. Chest x-ray as the names says only performed for the chest to find out whether cancer has spread in the lungs or not.

Positron emission tomography (PET) or PET-CT scan.

The name Positron emission tomography (PET) or PET-CT scan as the name says is usually combined with a CT scan. Positron emission tomography (PET) or PET-CT scan is usually performed to have pictures of organs and tissues inside the body. In this procedure, a small amount of sugar is injected inside the body, which is taken up by cells that use the maximum amount of energy. This is done because colon cancer uses energy actively; it absorbs more of the radioactive substance. Positron emission tomography (PET) or PET-CT is generally not performed for colon patients and if this test is needed, then on the specific situation.

Once the diagnosis of colon cancer is made, and the colon cancer is detected, the doctor then the analysis that which tests are to be performed or which treatment is to be taken.

Staging of colon cancer

Staging of colon cancer means the stage or the condition of your colon cancer as per the doctor after examining or diagnosing your colon cancer. Staging is the kind of the way, which describe the lactation, condition, the amount it has spread in the other parts of the body, and to check that to what extent it is affecting the body. In the process of diagnosis of colon cancer, doctors can figure out the stage of your colon cancer too.

There are standard five stages of colon cancer, i.e. Stage 0 to stage l to stage lV. These standard stages are then combined by the doctor to determine the stage of cancer for each person.

There are different types of stages description of colon cancer.

TNM Staging system

T stands for Tumor. In this stage, zero to IV stage is combined to describe how deep is the primary tumour has grown into bowel lining. This stage is further divided into sub lines listed below

TX: the first and primary stage in which tumour cannot be evaluated

T0: Zero evidence of colon cancer

This: cancer in situ. Cells found only in the epithelium

T1: The cancer cells grow in the layer of tissue underneath the mucosa or lining of the colon.

T2: Tumour grows up in a deeper and thick layer of muscles.

T3: The tumour grows in subserosa. The subserosa is a thin layer of connective tissue, which is underneath on the outer layer of the large intestine.

T4a: tumour grows on the surface of visceral peritoneum.

T4b: when a tumour grows in one part of the organ and transmits later to a different part.

N stands for lymphatic Node, which is as tiny bean-shaped organs are present throughout the body. This aids the immune system to fight against the other injections. The N stage is then further divided into subparts those are as follows

NX: In this stage, Lymph nodes are not able to evaluate

N0: regional lymph does not spread to lymph nodes.

N1a: One tumour cell is found in regional lymph nodes.

N1b: Two or three tumour cells are found in regional lymphatic nodes

N2a: 4 to 6 tumour cells found in regional lymphatic nodes

N2b: Seven or more than seven tumour cells are found in lymphatic nodes

In addition, M stands for metastasis in this stage cancer cells spread to other parts of the body.

M0: the stage when cancer cells have not spread to distant parts of the body.

M1a: this stage is when the colon cancer has spread to one other part of the body

M1b: colon cancer has spread to more than 1 part of the body in this stage.

M1c: the stage when colon cancer reaches to the peritoneal surface.

● Grade (G)

The doctors also describe colon cancer stages in terms of grades. In this type of staging, doctors compare the healthy tissue with affected tissue. Healthy tissue generally is in different groups. When the cancerous cells do not resemble the healthy tissue completely then, it is called” poorly differentiated” or also called” called high-grade tumour”. In this staging system, doctors can Figure out the spreading of cancerous cells to other body organs. The grades are further divided into different parts like

GX: the stage when tumour grade cannot be identified.

G1: when cells more look like healthy cells

G2: when cancerous cells partially look like healthy cells

G3: when the cancerous cells look less healthy than healthy cells

G4: in this stage, cancerous cells look barely healthy

Cancer stage grouping

Stage 0: stage 0 of colon cancer is also known as” Situ”.

Stage I: in this, the cancer cells invaded the muscular layer of the colon or rectum. In this stage, cancer cells have not been spread into nearby tissue or lymphatic nodes.

Stage IIA: in this stage, cancer has moved through the wall of the colon or rectum and not spread to nearby tissues.

Stage IIB: in this stage, cancer grows to the line of the abdomen. The lining of the abdomen is also known as

visceral peritoneum.

Stage IIC: In stage IIC, colon cancer has spread to the wall of the colon or rectum and has grown into nearby structures

Stage IIIA: In this stage colon, cancer grows through the inner lining or into the muscle layers of the intestine. In this stage, colon cancer will spread to one or three lymphatic nodes and does not reach to the other parts of the body.

Stage IIIB: In this stage, cancer cells have grown to bowel walls and to one to three lymphatic nodes or to a nodule of tumour in tissues around the colon or rectum.

Stage IIIC: in this stage, the colon cancer cells spread to four or more lymphatic nodes. In this stage, also colon cancer does not reach to another distant part of the body.

Stage IVA: in this stage, colon cancer cells from bowel walls spread to one new another organ like lungs and liver.

Stage IVB: In this stage, colon cancer cells read to more than 1 part of the body.

Stage IVC: in this stage, colon cancer cells reaches to the peritoneum and even to some other part or organ.

Diagnosis of Colon Cancer