What are cancer-causing agents (Carcinogens) around us

                                                     

  What are the cancer-causing agents (Carcinogens) around us?

Nowadays in Sri Lanka, yearly about 10,000 cancer patients are directed to get medicine from government hospitals. Actually, it is an apparent health problem in our country. Therefore it is better to know about cancer-causing agents (carcinogens) around us.

What is a carcinogen? A carcinogen is a substance that can cause cancer.

Now we will see how cancer is formed? According to Molecular Biological experiments it has proved that changes in genes (Mutations) may cause cancer. Our bodies are made up of trillions of cells. These cells can divide in a regular pattern. This is done under the control of the cell nucleus. Sometimes cell division cannot be controlled by the cell nucleus.  This leads to cancers. There are genes in the nucleus that control cell division. Sometimes these genes may activate abnormally due to some reasons. (Mutations) These genes are called oncogenes. The cell which has oncogenes is called a faulty cell. Most mutated cells are either destroyed by the body’s immune system or die with no ill effect in the body. This faulty cell may divide to form a clone of identical cells. Eventually, an irregular mass of relatively undifferentiated cells called a tumor is formed. 

Tumor cells can break away and spread to the other parts of the body, particularly in the bloodstream or lymphatic system, causing secondary tumors. Sometimes these tumors spread and cause ill health and death. These types of tumors are called malignant. (Malignant means out of control and likely to cause death) and may cause death) The majority of these tumors do not spread and are described as benign tumors.

Four types of cancers can be found in the human body.

• The cancers found in epithelial tissues of the body Carcinoma e.g. in the ski
• The cancers are found in glandular epithelial tissues. Adenocarcinoma e.g. breast cancer
• The cancers are found in muscles and bones  Sarcoma e.g. bone cancer
• The cancers are found in blood and lymph tissues.  Leukemia, lymphoma

 Among these, carcinoma and Adenocarcinoma are common in adults. Lymphoma and sarcoma are common in young people. Leukemia and brain cancers are common in small children.

 Now we can consider the causes of cancer diseases.

Up to 20% percent of cancer worldwide may be caused by 2 types of viruses.  When RNA viruses like retroviruses invade animal cells they can alter the host cell division genes and cause the cells to become malignant. Some DNA viruses contain their own oncogenes which can cause uncontrolled cell division of host cells. Viruses which are cause warts in the cervix and results in cervical cancer E.g. Papillomavirus, Sexual herpes virus.

Up to 5% of human cancers tend to run in families. (Hereditary predisposition) More than 40 types of cancer, including cancer of the breast, ovary, and colon come into this category.

Environmental factors also cause cancer in human

·         Ionizing radiation

·         Ultra Violet radiation

·         Chemical mutagen

Ionizing radiation: This includes X- rays, Gamma rays, and particles of decaying radioactive elements. The radiation causes the formation of chemically active ions inside cells which can break DNA strands (genes) or cause mutations. Types of cancer linked with ionizing radiation include skin cancer, bone marrow cancer, lung cancer, and breast cancer.  Medical and dental X-rays also expose patients to ionizing radiation. Electromagnetic waves around high tension wires may also cause mutations of cells of the people who live closer to high tension electric cables. So these people also maybe are at risk of developing cancers. Sometimes some types of gemstones also may contain radioactive elements and these also may emit ionizing radiation.

Ultra Violet light: 

The most common form of carcinogenic radiation is non-ionizing

 colorings. DNA absorbs U.V light and that energy is used

 in converting the bases of DNA into more reactive forms which

 react with surrounding molecules. Sunlight contains U.V rays

 and prolonged exposure to it can result in skin cancers including

 melanoma. Brown skin pigment melanin offers some protection. 

Depletion of the ozone layer results in a higher proportion of U.V

 light reaching the surface of the Earth. Some gases like

 chlorofluorocarbon may cause the depletion of the ozone layer.

Chemical mutagens: 

Many chemicals are now recognized as causing

 cancer. Soot, coal

 tar, mineral oil, asbestos products synthetic dye,

 some food

 additives (flavors, colorings, and stabilizers) are

 possible

 carcinogens because they cause cancer

 in experimental animals. The

 chemicals found in beetle and tobacco also may

 cause cancers in the

 mouth, pharynx, and esophagus. Tobacco smoke

 may cause mouth, pharynx, and lung cancer. Many

 common foods contain carcinogenic compounds

 but levels are mostly low.

                        Controlling of cancer:

Control can be done in 3 ways

  1. Prevention: Protection against carcinogens

  2.  Early diagnosis- including screening programs

  3. Treatment- urgent action once the diagnosis is mad

 Now we can discuss some common cancers found in Sri Lanka.

Breast cancer: Commonest cancer among women in Sri Lanka. In the early stages, this will not cause any pain and could not be identified. At this stage, the size of the cancer is similar to a size of a marble. If it is diagnosed and treated at this stage it could be easily and completely curable. But when it comes to later stages it could not be cured. The screening test for breast cancer is mammography and involves X- raying the breast. But women can examine their breasts for early symptoms of cancer by themselves after following “breast awareness programs”. Government should arrange these programs for women

How to examine the breasts for cancer?

Every woman should examine her breasts for cancer on the same day of the month.  Women who have a menstruation cycle should do this at the end of each menstruation. First, they have to look for the abnormalities of the appearance of the breasts. These are some of the abnormalities which indicate a possibility of cancer.

•     Dipped nipples
•    Change in the size and the shape of the       breasts            
•    Wrinkling of the skin of the breasts
•    A secretion of nipples other than milk with blood or without blood
•     A thickened area or a lump that can be felt when touched.
•  Any protrusion of the skin or any depression of the skin

 How to look for the above signs?

 You can look for these signs by standing in front of a mirror with the naked bust.

1. First stand in front of a mirror keeping hands by side and looking for the above signs.

2. Then raise your hands and look.

3. Then keep your hands on your waist and press them to allow chest muscles to press and look for the above signs

4. Finally keep hands pressed on the waist and bend forward and look for the signs

Steps in examining the breasts for lumps

1. Lie down upwardly after keeping a pillow under the right shoulder. By using the three middle fingers of the left hand examine the right breast. To do so press and move the fingers upward and downward in a circular manner. Specially feel the places under the armpit.
2.  Examine the left breasts with the right hand.

  3. While you are bathing examine with soapy fingers.

Treatment for breast cancer:

• Surgery to remove breasts
• Radiotherapy of the breast using X-rays to kill tumor cells.
• Chemotherapy of the whole body using chemicals that kill dividing cells both normal and tumor cells.
• Using tamoxifen and anti-estrogen hormones.
• Treatment can be used in combination.

Cancers in the female reproductive system:

 Cervical cancer, uterine carcinoma, ovarian carcinoma, vaginal carcinoma, carcinoma of the Fallopian tubes

Cervical cancer: Cancers in the cervix are the second commonest cancer in women. The main cause for this is the human papillomavirus. Mostly found in sexually active women above thirty years. The disease is common in women who have many partners. The women who married early and have more children are also susceptible to the disease. Symptoms are can be seen only after the later stages of the disease. Later cancer may spread to the womb, vagina, bladder, and to the rectum. This cancer develops on the upper surface of the cervix. This can be identified by a cervical smear test. This is the screening test for cervical cancer and is called as “PAP test”. This is done by observing the scraped cells from the cervix through the microscope for the signs of abnormality which can lead to malignancy. PAP test should be done every five years.

The symptoms of cervical cancer:

• A smelly vaginal discharge mixed with blood
• Bleeding after having intercourse
• Irregular bleeding and could not identify the menstrual cycle
• Passing blood with urine and feaces
• Pain in back and lower abdomen

Treatment: No vaccination is found so far. Removing cancerous tissues by surgeries, using gamma radiation

Oral cancer: 

This is also common cancer among adult males in Sri Lanka. There are symptoms to identify oral cancer. Some of them are as follows:  Red or white patch in the lining of the mouth cavity, a fleshy growth in the mouth cavity, A wound inside the mouth cavity which is not healing for a long time. In later stages following symptoms can be seen.

Difficult to open the mouth

Difficult to swallow

Pain in swallowing

Causes for oral cancer:

 1. Chewing beetles with tobacco and lime (calcium hydroxide)

2. Keeping the chewed beetle in the mouth for a long time

3. Taking liquor

4. Smoking

5. A wound due to constant touching of a tooth in the lining of the mouth cavity.

 Lung cancer: The main cause of lung cancer is smoking. More than three million deaths annually occur in the world due to cancer in the lungs. Various types of smoking such as smoking cigarettes with or without filters, tobacco pipes, and cigars are had equally contributed to the disease. Inactive smoking (the people who stay near smokers are called inactive smokers) also may have the ability in leading to lung cancer. The tar in tobacco smoke will deposit in lung tissues and that part will be black in colour and airless.

Symptoms of lung cancer:

1.  Long-lasting cough    2. Loss of weight

3.  Cough and appearance of blood with sputum. 

4.  pain in the chest

Leukemia: Blood cells are produced by bone marrow cells.

 Sometimes abnormal bone marrow cells may produce a large

 number of white blood cells. (Uncontrollable cell division) In a healthy person, the average number of white blood cells in a

cubic millimeter is about 11, 000. But in a leukemia patient, this number is much higher than the above value. The other thing is most of these cells are immature and they can’t function well. In leukemia patients matured white blood cell count and red blood cell counts are lower than the normal range. Due to the loss of red blood cells, the patient will be anemic.

Causes for leukemia:  The causes are inconclusive so far.  But radiations like X- rays may be the cause. Most of the leukemia patients are children but adults also may have the disease

Symptoms of leukemia:

1. Susceptible to various infectious diseases
2.  Loss of body weight without any reason
3.  Loss of appetite
4.  Fever and sweating
5.  Breathing difficulties
6.  Swelling of lymph nodes
7.  Flowing of blood even from a small wound

                             Colon cancer

The colon is a part of the large intestine. This is the third most common cancer in Sri Lanka. In its early stages, symptoms could not be seen.

 The tumour causes bleeding of the gut wall, leading to anemia and traces of blood in the feaces. Affect the bowel movement causing diarrhea or constipation.  The presence of cancer can be revealed using a barium meal.

Treatment: The diseased section of the bowel is removed and the two ends of the gut are sewn together again. 80% chances of a complete cure if diagnosed early.

Cancer causes Growing evidence that diets relatively high in fat and meat may be associated with a higher occurrence of colon cancer, as well as some other forms of cancer. Reducing consumption of fatty foods and meat and frequently eating fresh fruit and vegetables and cereals with high fiber content can help to reduce the risk.

Are cancers preventable?

Should avoid known carcinogenic compounds, some viruses, and radiation. More vegetables and fruits rich in vitamins (A, B, and C) will reduce the susceptibility to the disease.

Are cancers curable?

If the cancers are diagnosed at the first stages they can be completely cured. If someone has the following symptoms should immediately consult a doctor.

  1. An incurable long-lasting wound in the mouth or any other place of the body

   2.  A lump or an abnormality found in breasts

  3. An unusual flowing of blood through the vagina or appearance of blood in feces or urine.

  4.  A change in the normal way of passing urine and feces.

  5.  A long-lasting incurable cough or change in voice

  6. Difficulties in swallowing and loss of appetite.  

  7. Sudden loss of weight 

These are the most probable carcinogens and cancers found among people worldwide.