Cancer

What is cancer ?

Cancer is not just one disease but many diseases. There are more than 100 different types of cancer. Most cancers are named for the organ or type of cell in which they start - for example, cancer that begins in the colon is called colon cancer; cancer that begins in basal cells of the skin is called basal cell carcinoma.

Cancer is a term used for diseases in which abnormal cells divide without control and are able to invade other tissues. Cancer cells can spread to other parts of the body through the blood and lymph systems.

Main categories of cancer

Carcinoma: cancer that begins in the skin or in tissues that line or cover internal organs.

Sarcoma: cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.

Leukemia: cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of abnormal blood cells to be produced and enter the blood.

Lymphoma and myeloma: cancers that begin in the cells of the immune system.

Central nervous system cancers: cancers that begin in the tissues of the brain and spinal cord.

Origins of cancer

All cancers begin in cells, the body's basic unit of life. To understand cancer, it's helpful to know what happens when normal cells b

ecome cancer cells.

The body is made up of many types of cells. These cells grow and divide in a controlled way to produce more cells as they are needed to keep the body healthy. When cells become old or damaged, they die and are replaced with new cells.

However, sometimes this orderly process goes wrong. The genetic material (DNA) of a cell can become damaged or changed, producing mutations that affect normal cell growth and division. When this happens, cells do not die when they should and new cells form when the body does not need them. The extra cells may form a mass of tissue called a tumor Not all tumors are cancerous; tumors can be benign or malignant.

• Benign tumors: aren't cancerous. They can often be removed, and, in most cases, they do not come back. Cells in benign tumors do not spread to other parts of the body.
• Malignant tumors: are cancerous. Cells in these tumors can invade nearby tissues and spread to other parts of the body. The spread of cancer from one part of the body to another is called metastasis.
• Leukemia: It is a cancer of the bone marrow and blood. Not from tumor

Common symptoms

• A thickening or lump in the breast or any other part of the body
• A new mole or a change in an existing mole
• A sore that does not heal
• Hoarseness or a cough that does not go away
• Changes in bowel or bladder habits
• Discomfort after eating
• A hard time swallowing
• Weight gain or loss with no known reason
• Unusual bleeding or discharge
• Feeling weak or very tired

Most often, these symptoms are not due to cancer. They may also be caused by benign tumors or other problems. Only a doctor can tell for sure. Anyone with these symptoms or other changes in health should see a doctor to diagnose and treat problems as early as possible. Usually, early cancer does not cause pain. If you have symptoms, do not wait to feel pain before seeing a doctor.

Screening test

Lab Tests

Tests of the blood, urine, or other fluids can help doctors make a diagnosis. These tests can show how well organ functioning. Also, high amounts of some substances may be a sign of cancer. These substances are often called tumor markers. However, abnormal lab results are not a sure sign of cancer. Doctors cannot rely on lab tests alone to diagnose cancer.

Imaging Procedures

Create pictures of areas inside body that help the doctor see whether a tumor is present. These pictures can be made in several ways:

• X-rays: X-rays are the most common way to view organs and bones inside the body.
• CT scan: An x-ray machine linked to a computer takes a series of detailed pictures of organs with contrast material (such as dye) to make these pictures easier to read.
• Radionuclide Scan: by injecting a small amount of radioactive material. It flows through bloodstream and collects in certain bones or organs. A machine called a scanner detects and measures the radioactivity. The scanner creates pictures of bones or organs on a computer screen or on film.. body gets rid of the radioactive substance quickly.
• Ultrasound: An ultrasound device sends out sound waves that people cannot hear. The waves bounce off tissues inside your body like an echo. A computer uses these echoes to create a picture called a sonogram.
• MRI: A strong magnet linked to a computer is used to make detailed pictures of areas in body. Doctor can view these pictures on a monitor and can print them on film.
• PET scan: after injecting a small amount of radioactive material. A machine makes pictures that show chemical activities in the body. Cancer cells sometimes show up as areas of high activity.

In most cases, doctors need to do a biopsy to make a diagnosis of cancer. For a biopsy, a sample of tissue is taken from identified tumor and sends it to a lab. A pathologist looks at the tissue under a microscope.

Biopsy

The sample may be removed in several ways:

With a needle: The doctor uses a needle to withdraw tissue or fluid.

With an endoscope: The doctor uses a thin, lighted tube (an endoscope) to look at areas inside the body. The doctor can remove tissue or cells through the tube.

With surgery: Surgery may be excision or incision

• In an excisional biopsy, the surgeon removes the entire tumor. Often some of the normal tissue around the tumor also is removed.
• In an incisional biopsy, the surgeon removes just part of the tumor. If the symptom or screening test result suggests cancer, the doctor must find out whether it is due to cancer or to some other cause.

18F SODIUM FLUORIDE BONE SCAN

What is it?

18F Sodium Fluoride Bone Scan is a state- of-the-art Skeletal Scintigraphy done on a PET-CT scanner. It is a highly sensitive and superior test compared to the regular Nuclear MDP Bone Scan and can be used in the same disease conditions like:

• Skeletal metastases (spread of cancer to bone) in known cancer patients
• Detection of fractures which are not seen on regular X-rays.
• Detection of bone infection which is not evident on routine X-rays
• Many other orthopedic applications like Sports Injuries, Metabolic bone diseases, Paget's disease etc

How is it different from conventional Bone Scan?

There is enough literature evidence to show that 18 F Sodium Fluoride Bone Scans are superior to conventional MDP bone scans in the early detection of skeletal Lesions

• The additional CT scan data available with the 18F bone scan provides anatomical information and helps in giving a precise diagnosis which aids the treating Physician in accurate treatment planning.

How is it done?

• It is a simple investigation done with a small, very safe IV injection of 18F Sodium Fluoride and the scan is done within half an hour of injection.

Preparation for the test?

• There is no prior preparation required for the bone scan. You may continue to eat and drink normally prior to, and after the scan. If you are on any medications, you may continue to take them.
• However a prior appointment is mandatory.

Caution

• This scan is not done in pregnant women unless it is indicated by the treating consultant. Please inform all the concerned personnel before you undergo the test
• Breast feeding mothers are advised to wean the baby for the whole day following the injection

What is the procedure?

A brief history of the patient's condition is taken and relevant previous reports are collected

• The patient is provided a comfortable dress for the procedure
• An IV canola is secured and the Isotope is injected
• He/she is then asked to wait in a room for 30 - 60 minutes
• After voiding the bladder, the patient is then taken for the Scan which takes 20- 25 minutes
• After the scan the IV cannula is removed, the patient is asked to change the dress and is given some light refreshments
• Old and new reports can be collected at the appointed time

68Gallium DOTA Peptide

PET/CT scan

68Gallium DOTA Peptide PET / CT scan - the ultimate in the diagnosis and management of Neuro Endocrine Tumors (NET).

What are Neuro Endocrine tumors?

These are the tumors which affect predominantly organs like GIT, pancreas, lung etc. Carcinoid tumors of GIT and lung, insulimnomas of pancreas, gastrinomas are to name a few. Some of these patients present with symptoms such as intractable diarrhoea, flushes etc. and are clinically classified as Carcinoid Syndrome

What is 68Gallium DOTA Peptide PET scan?

68Gallium DOTA Peptide is a short lived (half-life of about 1 hr) position emitting radionuclide tagged to peptides which will bind to the cell having these receptors in certain group of tumors called Neuro Endocrine tumors. It is used for the detection of these tumors, staging the disease before deciding the treatment options and after treatment to look for the response to treatment or recurrence.

The PET / CT scan done after the injection of 68Gallium DOTA Peptide is called 68Ga DOTA Peptide PET /CT scan.

How is it comparable with or different from CT scan & MRI?

This is a functional/metabolic scan which has much higher proven sensitivity and specificity in the NET, than the regular conventional imaging like CT & MRI. It helps in deciding about the treatment options in the patients and knows response to the treatment.

What are the pre-test precautions?

No preparation is necessary if the patient has already had a diagnostic CT. But if the patient requires CECT along with 68Gallium PET, then 2hrs fasting is mandatory.

What are the side effects?

68Gallium DOTA Peptide is absolutely safe. There are no side effects.

PET-CT Utilization Guidelines

Source: Portal Content Team