CANCERCHEMOTHERAPY
INDEX
WHAT IS CANCER?
TYPES OF CANCER
CAUSES OF CANCER
RISK FACTORS FOR CANCER
WARNING SIGNES
CANCER SCREENING
DIAGNOSIS
TREATMENT
UNDERSTANDING CHEMOTHERAPY
What is cancer?
Cancer is a general term used to describe cells that grow and spread around the body in an uncontrolled way.
*Our body is made up of millions of tiny cells which replace themselves whenever necessary. Forexample, they replace themselves when they get wornout, old or injured.
*The cells of our bodies grow and multiply in a process known as cell division. It must be extremely tightly controlled if all the cells in our body are to grow in the right place, and for all our organs and tissues to function properly. If cells divide too quickly the consequences can be disastrous.
* Cancer is essentially a diseaseof cell division. Uncontrolled cell division can have many causes and can happen in any type of cell in the body, but it usually results from defects or damage in one or more of the genes involved in cell division.
If these genes become damaged (mutated) in some way for example by exposure to cigarette smoke or ultraviolentradiation, the cell can start to divide uncontrollably. These defective cells can multiply to form a lump of abnormal tissue called a tumor.
What do the terms benign and malignant mean?
A tumor may be benign or malignant:
*A benign tumor is not cancer, does notspread, can usually be completely removed, is not likely to recur and doesnot usually present a serious threat to health.
*A malignant tumor is cancer, and can invade neighboring tissue and organsthrough your blood or lymph system (this is the system which helps fight infection) this is called metastasis and can start new or secondary cancers.
*The cells in almost any part of the body can become cancerous (only the hair nails and teeth can not get cancer) There are several hundred types of different types of cancers. Each happens for different reasons and each type of cancer is different. Some cancers develop slowly some quickly, some cancers have known causes whilst others have unknown causes.
*When cancer comes back in a person who appeared to be free of the disease after treatment, it is called recurrence
How does cancer spread?
A malignant tumor is made up of cancer cells when it first develops, this malignant tumor may be confined to its original site. This is known as cancer in situ (or carcinoma in situ) if these cells are not treated, they may spread beyond their normal boundaries and into surrounding tissues, becoming invasive cancer.
Some benign tumors are precancerous and may progress to cancer if left untreated. Otherbenign tumors do not develop into cancer.
For cancer yo grow bigger than the head of the pin it must grow its own blood vessels. This is called angiogenesis. Sometimescells move away from the original (primary) cancer , either by the tissue fluid channels(lymphatics) or in the blood stream, and invade other organs. When these cells reach a new site, they may continue to grow and form another tumor at that site. This is called a secondary cancer or metastasis.
How does cancer make you ill?
*Cancerous cells divide uncontrollably.
*On its own a single tumor can make you quiteill, for example by pressing against nerves, blocking the digestive system or blood vessels, or by releasing hormones that can affect the normal workings of your body.
*Things can get much worse, however, if the cancer becomes malignant and spreads. *This happens when a single cancerous cell breaks away from the main tumor and starts growing and dividing elsewhere in the body. Once a tumor metastasizes, it is much more difficult to treat and can make you much more ill because more areas of the body are affected.
*A cancer may also cause generalized symptoms such as fever, fatigue or weight loss. This may be caused by cancer cells releasing substances that change body’s metabolism or the cancer may cause the immune system to react in ways that produce this system.
How many different types of cancer are there?
*From one point of view, there are as many types of cancer as there are different people, because everyone’s genes are different and so no two cancers are exactly alike.
From another point of view, there are as many different types of human cell – just over 200.
*However cancers can be broadly grouped into differenttypes, depending on which tissues they come from.
Carcinomasthe most common types of cancer, arise from the cells known as epithelial cells that cover external and internal body surfaces Lungs , breast and colon are the most frequent cancers of this type
Sarcomas are cancers arising from cells found in the supporting tissues of the body such as bone, cartilage, fat connective tissue and muscle.
Lymphomasare cancers that arise in the lymph nodes and tissues of the body,s immune system.
Leukemiaare cancers of the immature blood cells that grow in the bone marrow and tend to accumulate in large numbers in the blood stream
Adenomasare tumors that come from glandular tissue like the thyroid the pituitary gland they are often benign.
What causes cancer?
*There is no one single cause for cancer. Scientists believe that it is the interaction of many factors together that produces cancer. The factors involved may be genetic environmental or constitutional characteristics of the individual.
*Anything that damages the genes in our cells can ultimately cause cancer the vast majority of cancers are caused by DNA damage that accumulates over a person’s lifetime (sporadic cancer). Cancers that are directly caused by genetic faults inherited from a parent are less common.
What are the risk factors for cancer?
A risk factor is anything thatmay increase a person’s chance of developing a disease .A risk factor does not necessarily cause the disease, but it may make the body less resistant to it. The following risk factors and mechanisms have been proposed as contributing to the development of cancer.
Lifestyle factors
Smoking,tobacco in any form, high-fat diet, lack of exercise or exposure to chemicals (cancer-causing substances) in the work place a over long period of time may be risk factors for some cancers.
Genetic factors
*Family history, inheritance and genetics may play an important role in some adult and childhood cancers. It is possible for cancer of varying forms to be present more than once in a family. Some gene alterations are inherited. However, this does not necessary mean that the personwill develop cancer. It indicates that the chance of developing cancer increases.
*There are two important types of genes that, when mutated can cause cancer-tumor suppressor genes and oncogenes.
Environmental hazards
During the course of a day, we are continually exposed to things that damage our DNA. Things that damage DNA are called carcinogens, and they include
Tobacco, car exhaust fumes, the sun, Natural and man made radiation, Asbestos, pesticides, fertilizers.
Many of these things cause damage because they react with the molecules in our cells to form free radicals. Free radicals are highly damaging molecules, and can wreak havoc on the sensitive machinery inside a cell.
Age
Age is an important risk factor for cancer. Cancer can occur at any age, but the risk of developing cancer increases with age. Over 70% of all newly diagnosed cancers occur in people aged 60 years or more. This is because the longer we live, the greater the number of potentially cancer-causing mutations in our DNA.
Viruses
Some viruses are linked to certain types of cancer. Possibly, the virus alters a cell in some way. This does not mean that these cancers spread from person to person like an infection, and does not mean that every one infected with these viruses will develop cancer.
E.g.: Human papilloma virus(HPV) cervical cancer , Hepatitis B and C viruses-primary liver cancer , Human T-cell leukaemia, virus leukaemia,Eppstein-Barr virus (EBV) can occasionally cause some types of childhood cancers ,carcinomas and lymphomas ,Human immunodeficiency virus is linked to several cancers as it weakens the immune system.
What are the warning signs of cancer?
The chances of curing cancer increase with early detection
The Indian Cancer Society and other organizations recommend paying attention to the seven warning signs of cancer:
1. Changes in bowel or bladder habits
2. Unusual bleeding or discharge
3. A sore that does not heal
4. Indigestion or difficulty swallowing
5. A nagging cough or hoarseness
6. A thickening or lump in the breast or elsewhere
7. An obvious change in a wart or mole
A physician can detect cancer by taking a medical history, performing routine check ups, cancer screening tests, imaging techniques and tissue biopsy.
What is cancer screening?
They are tests designed to detect cancer when one does not have any symptoms. They include:
1 Digital rectal examination
2 Pelvic examinations
3 Breast self examination
4 Pap test
5 Mammography
How is cancer diagnosed?
There is no single test that can accurately diagnose cancer. The complete evaluation of a patient usually requires a thorough history and physical examination along with diagnostic testing. Many tests are needed to determine whether a person has cancer, or if another condition (such as an infection) is mimicking the symptoms of cancer. Effective diagnostic testing is used to confirm or eliminate the presence of disease, monitor the disease process, and to plan for and evaluate the effectiveness of treatment.
There are number of ways to diagnose cancer.
Diagnostic blood tests- They are designed to identify a tumor caused impairment.
Blood tests like
CBC-Complete blood counts and Differential white blood cell counts.
Tumor markers: Tumor markers are substances either released by cancer cells into the blood or urine or substances created by the body in response to cancer cells. Tumor markers are used to evaluate how well a patient has responded to treatment and to check for tumor recurrence. E. g., Alpha fetoprotein (AFP) carcinoembryonic antigen (cea), prostate specific antigen (psa), etc are used to indicate the presence of tumor.
IMAGING TECHNIQUES- imaging is the process of producing valuable pictures of body structures and organs. It is used to detect tumors and other abnormalities.
To determine the extent of disease, and to evaluate the effectiveness of treatment. Imaging may also be used when performing biopsies and other surgical procedures.
X-RAYS_ X-rays are .diagnostic tests that use invisible electromagnetic energy beams to produce images of internal tissues ,bones ,and organs on film-rays may be taken of any part of the body to detect tumor (or cancer)cells.
Computed Tomography Scan (Also called a CT SCAN OR Computed Axial Tomography or CAT scan)CAT scan is a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images(often called slices) both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones muscle, fat, and organs. CT scans are more detailed than general x-rays. CTscans can also be a huge help in planning surgery or radiotherapy.
MRI scans (Magnetic Resonance Imaging): MRI, uses magnetism rather than x-rays to build up picture of the insides of your body.
MRI scan can be used like a CT scan to view slices through the body, or can make 3D images of your organs. It usually produces a more detailed view of the body than x-rays, so doctors often use MRI to examine your head and brain. It can also be used to measure blood flow.
PET scan (Positron Emission Tomography)This test uses a form of sugar that contains a radioactive atom. Cancer cells absorb high amounts of this sugar. A special camera can then spot these cells.PET is useful when the doctor thinks the cancer has spread but doesn’t know where. It may also be useful in checking lymph nodes for cancer before they are removed.
Ultrasound: Ultrasound, or sonography, is the most commonly used type of reflection imaging. This technique uses high frequency sound waves and computer to create images, called sonograms, of blood vessels, tissue, and organs. Sonograms are used to view internal organs as they function and to assess blood flow through various vessels. Tumors in the abdomen, liver and kidneys can often be seen with an ultrasound.
Mammogram: mammogram is an x-ray examination of the breast. It is used to detect and diagnose breast disease in women. Mammography can not prove that an abnormal area is cancerous, but if it raises a significant suspicion of cancer, a biopsy may be performed.
Bone scan: This test can help showwhether the cancer has spread to the bones
Tissue biopsy: Abiopsy is a procedure performed to remove tissue or cells from the body for examination under a microscope to determine whether it is cancerous.
Endoscopic biopsy: This type of biopsy is performed through a fiberoptic endoscope(a long thin tube that has a close-focusing telescope on the end for viewing) through a natural body orifice(i. e. rectum) or a small incision. The endoscope is used to view the organ in question for abnormal or suspicious areas, in order to obtain a small amount of tissue for study.
Excisional or incisional biopsy: This type of biopsy is often used when wider or deeper portion of the skin is needed. When the entire tumor is removed, it is called excisional biopsy technique. If only a portion of the tumor is removed it is called incisional biopsy technique.
Fine needle aspiration {FNA} biopsy: this type of biopsy involves using a thin needle to remove fluid or very small pieces from a tumor. A computed tomography scan (CT OR CAT scan)-an x-ray procedure that produces cross sectional images of the body may beused to guide a needle into atumor in an internal organ such as the lung or liver.
These techniques are essential for locating and sampling tumors.
Endoscopy: An endoscope is a small,flexible tube with a light and a lens on the end used to look into the esophagus, stomach, duodenum, colon or rectum. It can also be used to take tissue from the body for testing or to take colour photographs of the inside of the body.
What are the treatment methods available for cancer?
There is no single treatment for cancer-doctors have a range of options available and must decide which is best for the patient. They will often combine several types of treatment for greater effect taking into account all sorts of factors.
There are currently many different ways to treat cancer.
Surgery
Surgery is complete or partial removal of tumor. It is used in several ways to help cancer patients. It provides the best chance to stop many types of cancer and it also plays a part in diagnosing, stagingand supporting cancer treatment. Several types of surgery are helpful to people with cancer.
Some surgeries are used in combination with other types of treatment.
The goal of surgery is to eliminate the cancer or in the case of advanced disease; relievesymptoms and achieve long term remission. The goal is to:
- Remove the primary cancer.
- Leave an area around the cancerous site that is free of cancer cells. Therefore no cancer cells are present in thetissue surrounding the surgery site.
- Remove nearbylymph nodes. The nodes are then examined to see if they contain any cancer cells.
- This is the important to correctly stage the cancer.
Having surgery for cancer is different for every patient depending on the type of surgery; the type of cancer and the patient’s health.
2 RADIATION THERAPY
Radiotherapy uses precisely targeted high-energy rays to kill cancer cells. It does this by damaging a cells internal components (molecules) causing the cells to commit suicide by apoptosis.
Radiotherapy is usually required for one of the following reasons:
- As a stand –alone treatment to cure cancer.
- To shrink a cancer before surgery.
- To reducethe risk of a cancer coming back after surgery.
- To complement chemotherapy.
- To control symptoms and improve quality of life if a cancer is too advanced to cure.
Radiation therapy is given through different methods; depending on the type of cancer, the location of the cancer and the patient’s health. Sometimes, radiation therapy is used in combination with others treatments .The following are some of the different types of radiation therapies:
- External radiation ( external beam therapy)
Radiation isadministered bye large machine, outside the body, that points the energy waves directly at the tumor.
- Internal radiation (brachytherapy,implant radiation)
With internal radiation (brachytherapy, implant radiation), a high dose of radiation is given inside the body as close to the cancer as possible. The radiation treatment may be swallowed, injected, or implanted directly into the tumor. Aim is to administer a higher dose of radiation in a shorter time span.