Cancer Types and Causes PDF

CANCER Cancer is a disease where some cells in the body start growing uncontrollably and don't behave like normal cells. These abnormal cells can form lumps called tumors (in solid cancers) or spread through the blood (in cancers like leukemia). Unlike normal cells that grow, divide, and die in an...

CANCER Cancer is a disease where some cells in the body start growing uncontrollably and don't behave like normal cells. These abnormal cells can form lumps called tumors (in solid cancers) or spread through the blood (in cancers like leukemia). Unlike normal cells that grow, divide, and die in an orderly way, cancer cells keep growing and dividing without stopping. Normally, cells know when to stop growing, but cancer cells lose this control. They keep multiplying, creating more and more cells, which can form a tumor. When cells are old or damaged, they usually die in a process called apoptosis. Cancer cells avoid this and continue to live even when they’re abnormal, letting them build up. As tumors grow, they need food and oxygen. Cancer cells make the body grow new blood vessels (called angiogenesis) to feed the tumor, helping it grow bigger. Cancer cells can break away from the original tumor and travel to other parts of the body through the blood or lymphatic system. This is how cancer spreads, forming new tumors elsewhere. Normally, the immune system (the body's defense system) destroys harmful cells. But cancer cells can trick the immune system and hide, allowing them to grow without being attacked. Types of cancer There are over 100 types of cancer. Healthcare providers categorize them according to where they start in your body and the type of tissue they affect. There are three broad cancer classifications: Solid cancers: This is the most common type of cancer, making up about 80% to 90% of all cases. This includes carcinoma that forms in epithelial tissue (like your skin, breast, colon and lungs) and sarcoma that forms in bone and connective tissues. Blood cancers: These are cancers that start in your blood cells or lymphatic system. Examples include leukemia, lymphoma and multiple myeloma. Mixed: Cancers that involve two classifications or subtypes. Examples include carcinosarcoma and adenosquamous carcinoma. Malignant - spread ( different place) Benign - not spread ( one place) Different types of cancer 1. Carcinoma Carcinomas are the most prevalent type of cancer, starting in the epithelial cells that line the surfaces of organs and tissues throughout the body. These cancers can develop in various places, including the skin, lungs, breast, colon, and prostate. Carcinomas often grow slowly but can become aggressive. Common symptoms might include unusual lumps, changes in skin appearance, or persistent coughing. 2. Sarcoma Sarcomas originate in the body's connective tissues, including bones, muscles, fat, blood vessels, and cartilage. They are much rarer than carcinomas. Symptoms often vary depending on the location and may include pain, swelling, or the presence of a noticeable lump. Because sarcomas can occur in any connective tissue, their effects can be diverse. 3. Leukemia Leukemia is a cancer of the blood and bone marrow, characterized by the overproduction of abnormal white blood cells. Unlike solid tumors, leukemia does not form tumors in the traditional sense but affects the blood’s ability to function correctly. Symptoms can include fatigue, frequent infections, easy bruising or bleeding, and unexplained weight loss. 4. Lymphoma Lymphoma starts in the lymphatic system, which plays a crucial role in the immune system. It can cause the lymph nodes to swell and may affect other areas like the spleen and bone marrow. Symptoms often include swollen lymph nodes, fever, night sweats, and unexplained weight loss. There are different types of lymphoma, but all are characterized by the uncontrolled growth of lymphocytes, a type of white blood cell. 5. Myeloma Myeloma primarily affects plasma cells, which are responsible for producing antibodies that help the body fight infections. This type of cancer leads to the production of abnormal plasma cells, which can disrupt normal blood cell production and weaken bones. Common symptoms include bone pain, fatigue, frequent infections, and kidney problems. 6. Melanoma Melanoma originates in the melanocytes, the cells responsible for producing pigment in the skin. This type of skin cancer is often associated with excessive sun exposure and can spread quickly to other parts of the body if not treated early. Signs of melanoma include changes in the size, shape, or color of moles, as well as the appearance of new pigmented areas. 7. Brain and Spinal Cord Tumors These cancers begin in the brain or spinal cord and can be either primary (starting in the brain) or secondary (spreading from another part of the body). Symptoms may vary widely, including headaches, seizures, vision or hearing problems, and changes in cognitive function. Depending on their location and size, these tumors can exert pressure on surrounding brain tissue and disrupt normal functions. 8. Germ Cell Tumors Germ cell tumors develop from the cells that produce sperm or eggs and can occur in the testes, ovaries, or other areas of the body. These tumors can be benign or malignant and often present as lumps or masses in the affected area. Symptoms may include pain or swelling in the testes or abdomen. 9. Neuroendocrine Tumors Neuroendocrine tumors arise from cells that release hormones into the bloodstream and can occur in various organs, including the lungs, digestive tract, and pancreas. These tumors can produce hormones, leading to various symptoms depending on their location and hormone production. Symptoms may include flushing, diarrhea, or abdominal pain. 10. Mesothelioma Mesothelioma is a rare cancer that primarily affects the lining of the lungs (pleura) or the abdomen (peritoneum). It is most often linked to asbestos exposure. Symptoms can include persistent cough, chest pain, difficulty breathing, and abdominal swelling. Due to its late diagnosis, mesothelioma can be particularly aggressive. Each type of cancer behaves differently, affecting treatment options and prognosis. Understanding these types helps in recognizing symptoms early and seeking appropriate medical care. Cancer Causes: 1. Genetic Mutations: ○ Inherited Mutations: Some cancers are linked to specific gene mutations passed down through families. For example, mutations in the BRCA1 and BRCA2 genes significantly increase the risk of breast and ovarian cancers. ○ Acquired Mutations: Most cancers are due to mutations that occur over a person’s life due to environmental exposures or lifestyle choices, not inherited ones. 2. Lifestyle Factors: ○ Smoking and Tobacco Use: Tobacco is a major cause of cancers, especially lung, mouth, throat, and pancreatic cancer. Tobacco contains carcinogens that damage DNA. ○ Diet and Nutrition: Diets high in processed foods, red meat, and low in fruits and vegetables are associated with certain cancers, particularly colorectal cancer. High alcohol intake is linked to liver, mouth, throat, and esophageal cancers. ○ Physical Inactivity and Obesity: A sedentary lifestyle and obesity are associated with an increased risk of cancers like breast, colon, and endometrial cancer. 3. Environmental Exposures: ○ Radiation: UV radiation from the sun is a well-known cause of skin cancers, including melanoma. Ionizing radiation (from sources like X-rays) can increase the risk of cancers like leukemia and thyroid cancer. ○ Chemicals: Long-term exposure to carcinogens such as asbestos, benzene, and formaldehyde can increase the risk of cancers like lung cancer and mesothelioma. ○ Air Pollution: Pollutants, especially particulate matter, can contribute to cancers, especially in the respiratory system. 4. Infections: ○ Human Papillomavirus (HPV): HPV infection is strongly associated with cervical, anal, and some head and neck cancers. ○ Hepatitis B and C: These viral infections increase the risk of liver cancer by causing long-term inflammation.  ○Helicobacter pylori (H. pylori): This bacterium, often associated with stomach ulcers, is also a risk factor for gastric cancer. 5. Hormonal Imbalances: ○ Hormone Replacement Therapy (HRT): Long-term HRT can increase the risk of breast and ovarian cancer. ○ Endogenous Hormones: High levels of estrogen (without balancing progesterone) over long periods, such as in early menstruation and late menopause, are associated with an increased risk of breast cancer. Cancer Symptoms: Symptoms vary significantly depending on the cancer’s location, size, and spread. Some general and specific symptoms include: 1. Unexplained Weight Loss: ○ Often one of the first noticeable symptoms, especially for cancers like stomach, lung, and pancreas. The body might use more energy to fuel cancer cells, leading to weight loss. 2. Persistent Fatigue: ○ Common in most types of cancer. This fatigue does not improve with rest and can be debilitating. It’s due to cancer’s toll on the body, changes in metabolism, or anemia. 3. Pain: ○ Pain can be localized to the cancer site (like a painful lump in breast cancer) or widespread if the cancer spreads. Bone pain can be a sign of cancers that metastasize to the bone, while headaches may indicate brain tumors. 4. Skin Changes: ○ Notable changes like new moles or sores that don’t heal, especially with irregular borders, multiple colors, or growing size, can indicate skin cancers like melanoma. Yellowing skin (jaundice) might indicate liver cancer. 5. Changes in Bowel or Bladder Habits: ○ Blood in stool or urine, constipation, diarrhea, or frequent urination can signal cancers of the bladder, colon, or prostate. 6. Unusual Bleeding or Discharge: ○ Unexplained bleeding can be an early sign of cancers in various organs, such as rectal bleeding in colon cancer or abnormal vaginal bleeding in uterine or cervical cancer. 7. Lumps or Thickening of Tissue: ○ The presence of lumps, especially in areas like the breast, testicles, or lymph nodes, could indicate cancerous growths. 8. Persistent Cough or Hoarseness:  ○ A chronic cough or voice change might point to lung or throat cancers, especially if accompanied by blood in sputum. Cancer Complications Complications can arise from the cancer itself, its location, spread, or treatment. Common complications include: 1. Metastasis: ○ Cancer cells can spread to other parts of the body (metastasize) and cause secondary tumors, worsening prognosis. Lung, bone, liver, and brain are common sites for metastasis. 2. Organ Failure: ○ Tumor growth can impair the function of organs, leading to organ failure. For example, liver cancer can lead to liver failure, while lung cancer might impair breathing. 3. Infections: ○ Cancer and treatments (especially chemotherapy) weaken the immune system, making patients more susceptible to infections. 4. Anemia: ○ Many cancers can lead to anemia due to blood loss (as in gastrointestinal cancers), bone marrow suppression (from treatments), or nutrient deficiencies, causing fatigue and weakness. 5. Blood Clots: ○ Some cancers increase the risk of clotting, leading to complications like deep vein thrombosis (DVT) or pulmonary embolism (PE). 6. Pain and Discomfort: ○ Cancer and treatments can cause severe pain, affecting quality of life. Pain management is a crucial part of cancer care. 7. Psychological Impacts: ○ Cancer diagnosis and treatment often lead to depression, anxiety, and a range of emotional challenges for patients and their families.