Cancer is a group of diseases that involve abnormal cell growth and can affect any part of the body. According to the World Health Organization, cancer is the second leading cause of death globally, accounting for an estimated 9.6 million deaths in 2018. In this article, we will explain what cancer is, how it develops, what are the main types of cancer, what are the signs and symptoms of cancer, how cancer is diagnosed and treated, and what you can do to reduce your risk of cancer or support someone who has cancer.
Table of Contents
What Is Cancer?
Cancer is a term that describes a group of diseases that involve abnormal cell growth and can affect any part of the body. These cells can invade and destroy surrounding healthy tissue, including organs. Some types of cancer cause visible growths called tumors, while others do not. Cancer can also spread throughout the body, a process known as metastasis. Cancer is a major cause of death worldwide.
Cancer is caused by changes in the DNA of cells, which control how they grow and divide. These changes can be inherited from parents or acquired during a person’s lifetime due to exposure to environmental factors, such as tobacco smoke, radiation, chemicals, infections, or lifestyle choices. Some of the most common risk factors for cancer include:
- Lack of physical activity
- Poor diet
- Excessive drinking of alcohol
- Certain infections
- Exposure to ionizing radiation
- Environmental pollutants
Cancer can be detected by certain signs and symptoms or screening tests. It is then typically further investigated by medical imaging and confirmed by biopsy. Staging is a process of determining the extent of the disease.
Treatment depends on the type of cancer, the extent of the disease, and the patient’s overall health. Options include surgery, radiation therapy, chemotherapy, targeted therapy, and hormone therapy. Pain and symptom management are an important part of care. Palliative care is particularly important in people with advanced disease.
The chance of survival depends on the type of cancer, extent of disease, and patient’s age and overall health. In the developed world, the five-year survival rate for all cancers is about 50%.
How Does Cancer Develop?
Cancer is a disease that occurs when the normal mechanisms that regulate cell growth and division fail, leading to the formation of abnormal cells that can invade and destroy healthy tissue.
Cancer can affect any part of the body and any type of cell. Cancer is caused by mutations in the DNA of cells, which are the molecules that carry the genetic information for making proteins and other molecules that control the cell’s functions.
Mutations can occur randomly during cell division, or they can be induced by external factors, such as exposure to tobacco smoke, radiation, chemicals, or viruses.
Most mutations are harmless or fixed by the cell’s own repair systems, but some mutations can alter the genes that control the cell’s behavior, such as:
- Oncogenes, which are genes that normally stimulate cell growth and division. When mutated, they can become overactive and cause excessive cell growth and division.
- Tumor suppressor genes, which are genes that normally inhibit cell growth and division. When mutated, they can become inactive and fail to stop abnormal cell growth and division.
- DNA repair genes, which are genes that normally help to fix DNA damage. When mutated, they can become defective and allow DNA damage to accumulate.
For a cell to become cancerous, it usually needs to acquire several mutations in different genes over time. This can take many years or decades.
As the mutations accumulate, the cancer cells can become more aggressive or resistant to treatment. Some cancers form solid masses called tumors, while others affect the blood cells or the immune system and circulate throughout the body.
There are more than 100 types of cancer, each with different characteristics and outcomes. The type of cancer is determined by where it originates and what type of cell it affects. For example, lung cancer starts in the lung and affects lung cells, while breast cancer starts in the breast and affects breast cells.
Cancer is a major cause of death worldwide, but many cancers can be prevented or detected early by following healthy lifestyle habits and getting regular screening tests. Some ways to reduce your risk of cancer or find it early are:
- Quit smoking or avoid exposure to secondhand smoke, as smoking is the leading cause of preventable cancer deaths.
- Eat a balanced diet rich in fruits, vegetables, whole grains, and lean proteins, as a healthy diet can help to protect your cells from damage.
- Exercise regularly, as exercise can help to reduce your risk of cancer by helping to protect your cells from damage.
- Get vaccinated against human papillomavirus (HPV) and hepatitis B virus (HBV), which can cause cervical, anal, liver, and other cancers.
- Get screened for cancer according to your age, gender, family history, and personal risk factors. Screening tests can help to detect cancer early when it is easier to treat and cure.
What Are the Main Types of Cancer?
Cancer is a disease that occurs when abnormal cells grow and divide uncontrollably and can invade and destroy healthy tissue. There are over 100 different types of cancer, but they can be grouped into four main categories based on the type of cell they start from:
- Carcinoma: This is the most common type of cancer, accounting for about 85% of all cancers. Carcinoma starts in the epithelial cells, which are the cells that line or cover the skin, organs, and body cavities. There are different subtypes of carcinoma, such as adenocarcinoma, which develops in an organ or gland, and squamous cell carcinoma, which originates in the flat, surface-covering cells. Some examples of carcinomas are breast cancer, lung cancer, colon cancer, prostate cancer, and skin cancer.
- Sarcoma: This is a rare type of cancer, accounting for about 1% of all cancers. Sarcoma starts in the connective or supportive tissues, such as bone, cartilage, fat, muscle, blood vessels, or nerves. There are different types of sarcoma, such as soft tissue sarcoma and bone sarcoma. Some examples of sarcomas are osteosarcoma, chondrosarcoma, liposarcoma, and leiomyosarcoma.
- Leukemia: This is a type of cancer that starts in the blood-forming cells in the bone marrow. Leukemia causes large numbers of abnormal blood cells to be produced and enter the bloodstream. There are different types of leukemia, such as acute lymphocytic leukemia (ALL), chronic lymphocytic leukemia (CLL), acute myeloid leukemia (AML), and chronic myeloid leukemia (CML). The types of leukemia are classified based on how fast they progress (acute or chronic) and what type of blood cell they affect (lymphoid or myeloid).
- Lymphoma: This is a type of cancer that starts in the lymphocytes, which are a type of white blood cell that helps fight infections and diseases. Lymphocytes are part of the lymphatic system, which is a network of vessels and organs that carry lymph fluid throughout the body. There are different types of lymphoma, such as Hodgkin lymphoma and non-Hodgkin lymphoma. Hodgkin lymphoma is characterized by the presence of abnormal cells called Reed-Sternberg cells in the lymph nodes. Non-Hodgkin lymphoma is a group of more than 60 different types of cancers that affect different types of lymphocytes.
The type of cancer you have will determine the symptoms you experience, the treatment options available to you, and the outcome you can expect. For example, surgery is often used to treat carcinomas and sarcomas, while chemotherapy and radiation therapy are often used to treat leukemias and lymphomas.
What Are the Signs and Symptoms of Cancer?
Cancer is a disease that occurs when abnormal cells grow and divide uncontrollably and can invade and destroy healthy tissue. Cancer can cause different symptoms, depending on where it is in the body and how much it affects nearby organs or tissues. Some symptoms may be caused by cancer itself, while others may be caused by the treatment or the body’s response to the disease.
The signs and symptoms of cancer can vary depending on the type of cancer and the extent of the disease. However, some common signs and symptoms include:
- Lump or area of thickening: This can be felt under the skin or seen as a swelling or a mass. A lump can be caused by a tumor growing in an organ or tissue, such as the breast, testicle, or lymph node. Not all lumps are cancerous, but they should be checked by a doctor to rule out cancer.
- Unexplained weight loss. This can include unintended weight loss or weight gain. Weight loss can be caused by cancer cells using up the body’s nutrients, or by loss of appetite, nausea, vomiting, or diarrhea. Weight gain can be caused by fluid retention, hormonal changes, or medications.
- Fatigue. This is a feeling of extreme tiredness that does not get better with rest. Fatigue can be caused by cancer cells using up the body’s energy supply or by the side effects of treatment, such as chemotherapy or radiation therapy.
- Bleeding. This can occur from any part of the body, including the nose, gums, rectum, or vagina. It can also include bleeding from any part of the body that is not normal for you. Unexplained bleeding or bruising can be caused by cancer affecting the blood cells, such as leukemia.
- Change in bowel habits. This can include diarrhea, constipation, or a change in the consistency of stool.
- Change in bladder habits. This can include urinary frequency, urgency, or pain.
- Skin changes. This can include yellowing of the skin and eyes (jaundice), darkening or redness of the skin, sores that do not heal, or changes to existing moles. Skin changes can be caused by cancer affecting the skin itself, such as melanoma, or by cancer affecting other organs, such as the liver or pancreas.
- Pain. This can occur in any part of the body, and it can be constant or intermittent.
- Fever. This is a body temperature that is higher than normal. This can include having a fever of 100.4°F (38°C) or higher for more than two weeks without a known cause. Persistent fevers and night sweats can be caused by cancer affecting the immune system, such as leukemia or lymphoma.
- Night sweats. These are episodes of sweating that occur at night.
- Persistent cough or trouble breathing: This can include coughing up blood, wheezing, shortness of breath, or chest pain. Persistent cough or trouble breathing can be caused by cancer affecting the lungs, such as lung cancer, or the throat, such as laryngeal cancer.
- Difficulty swallowing: This can include pain or discomfort when swallowing food or liquids. Difficulty swallowing can be caused by cancer affecting the mouth, throat, esophagus, or stomach.
- Hoarseness: This is a change in the voice quality, such as sounding raspy, weak, or breathy. Hoarseness can be caused by cancer affecting the vocal cords, such as laryngeal cancer.
- Persistent indigestion or discomfort after eating: This can include heartburn, bloating, gas, nausea, vomiting, or stomach pain. Persistent indigestion or discomfort after eating can be caused by cancer affecting the stomach, esophagus, pancreas, gallbladder, or liver.
- Persistent, unexplained muscle or joint pain: This can include pain that does not go away or gets worse with time. Persistent, unexplained muscle or joint pain can be caused by cancer affecting the bones, muscles, nerves, or joints.
These are some of the possible signs and symptoms of cancer,
but they are not specific to cancer and can be caused by other conditions as well.
If you have any signs or symptoms that do not go away or get worse, you should see a doctor to find out what is causing them.
If cancer is not the cause, a doctor can help figure out what the cause is and treat it, if needed.
If cancer is the cause, a doctor can help diagnose the type and stage of the cancer and recommend the best treatment options for you.
How Is Cancer Diagnosed and Treated?
Cancer is a disease that occurs when abnormal cells grow and divide uncontrollably and can invade and destroy healthy tissue. The diagnosis and treatment of cancer can vary depending on the type and location of cancer and the extent of the disease. However, there are some general steps that are typically followed.
The first step in diagnosing cancer is a physical exam. Your doctor will look for any signs or symptoms of cancer, such as lumps, masses, skin changes, or organ enlargement. You may also have lab tests, such as blood tests, urine tests, or other body fluid tests, to measure certain substances that may indicate cancer or its effects on your organs.
The next step in diagnosing cancer is imaging tests. These are tests that create pictures of the inside of your body and look for any abnormal growths or masses. Some common imaging tests used to diagnose cancer include X-rays, CT scans, MRI scans, PET scans, ultrasounds, or other methods.
The final step in diagnosing cancer is a biopsy. This is a procedure in which a small sample of tissue or cells is removed from the suspicious area and examined under a microscope. This is the only way to confirm if you have cancer and what type of cancer it is.
Once cancer is diagnosed, your doctor will determine the stage of your cancer. The stage of your cancer is how far it has spread and how aggressive it is. The stage of your cancer will help your doctor plan the best treatment options for you.
The treatment of cancer depends on many factors, such as the type, stage, location, and characteristics of your cancer, as well as your overall health and preferences. Some common types of treatment for cancer include:
- Surgery: This is the removal of the tumor and some surrounding healthy tissue to prevent the cancer from coming back. Surgery may also be used to remove lymph nodes or other organs that are affected by cancer.
- Radiation therapy: This is the use of high-energy rays or particles to kill cancer cells or shrink tumors. Radiation therapy can be given externally (from a machine outside your body) or internally (from radioactive sources placed inside your body near the tumor).
- Chemotherapy: This is the use of drugs to kill cancer cells or stop them from growing and dividing. Chemotherapy can be given orally (by mouth), intravenously (through a vein), intramuscularly (into a muscle), subcutaneously (under the skin), or directly into the affected organ or cavity.
- Immunotherapy: This is the use of drugs or other substances to stimulate your immune system to fight cancer cells. Immunotherapy can be given as injections, pills, creams, or infusions.
- Targeted therapy: This is the use of drugs or other substances that target specific molecules or genes that are involved in the growth and survival of cancer cells. Targeted therapy can be given as pills, injections, or infusions.
- Hormone therapy: This is the use of drugs or surgery to block or lower the levels of hormones that stimulate some types of cancer cells to grow. Hormone therapy can be given as pills, injections, implants, or surgery.
You may receive one or more types of treatment for your cancer, depending on your situation and goals. You may also receive supportive care to help manage the side effects and complications of cancer and its treatment. Supportive care may include pain management, nutrition therapy, physical therapy, emotional support, complementary and alternative medicine, and palliative care.
The goal of cancer treatment is to cure the cancer or to control the cancer so that it does not spread. The type of treatment you receive will depend on the type of cancer you have and the stage of the cancer.
What Can You Do to Reduce Your Risk of Cancer or Support Someone Who Has Cancer?
Cancer is a disease that occurs when abnormal cells grow and divide uncontrollably and can invade and destroy healthy tissue. Cancer can be prevented or treated by making some lifestyle changes and getting regular screenings. Cancer can also be supported by yourself or your loved ones by seeking professional help and emotional support.
Some of the lifestyle changes that can help prevent or treat cancer are:
• Avoiding tobacco. Tobacco use is linked to many types of cancer, such as lung, mouth, throat, pancreas, bladder, and cervix. Quitting tobacco or never starting it can lower your risk significantly.
• Eating a healthy diet. A healthy diet can help to protect your cells from damage that can lead to cancer. Choose foods that are rich in fruits, vegetables, whole grains, beans, and healthy fats, such as olive oil. Limit your intake of processed meats, alcohol, refined sugars, and animal fats. Some foods that may help prevent lung cancer are cruciferous vegetables like Brussels sprouts, cabbage, cauliflower, and broccoli.
• Being physically active. Physical activity can help to reduce your risk of cancer by helping to protect your cells from damage and maintain a healthy weight. Being overweight or obese can increase your risk of some cancers, such as breast, prostate, colon, and kidney. Aim for at least 150 minutes of moderate-intensity physical activity or 75 minutes of vigorous-intensity physical activity per week.
• Protecting yourself from the sun. Sun exposure can cause skin cancer by damaging the DNA in your skin cells. Wear sunscreen, sunglasses, hats and protective clothing when you go outside. Avoid the sun between 10 a.m. and 4 p.m., when the rays are strongest.
• Getting vaccinated. Some viruses can cause cancer, such as human papillomavirus (HPV) and hepatitis B. Getting vaccinated against these viruses can protect you from cervical, anal, liver, and other cancers.
• Getting screened for cancer. Screening tests can help detect cancer early when it is easier to treat and cure. Talk to your doctor about which screening tests are appropriate for you, based on your age, gender, family history, and personal risk factors.
Some of the ways to support yourself or someone who has cancer are:
- Talking to your doctor: Your doctor can provide you with information about your cancer and treatment options. They can also help you manage any symptoms or side effects you may experience.
- Joining a support group. Support groups can provide you with emotional support and information from other people who are going through the same thing. You can find support groups online or in your community.
- Taking care of yourself. This includes eating a healthy diet, getting enough sleep, exercising regularly, and doing things that make you happy. Taking care of yourself can help you cope with the stress and challenges of cancer.
- Seeking counseling or therapy. Cancer can cause physical and emotional distress that may require professional help. Counseling or therapy can help you deal with your feelings and emotions, such as fear, anger, sadness, or anxiety.
- Being there for them. If you know someone who has cancer, let them know that you are there for them and that you care. Listen to their feelings and concerns without judging or offering advice unless they ask for it. Respect their decisions and preferences about their treatment and care.
- Helping them with practical things. If you know someone who has cancer, offer practical help with daily tasks, such as cooking, cleaning, driving or running errands. This can make their life easier and show them that you care.
- Staying positive. Cancer is a difficult disease, but it is important to stay positive and hopeful. Encourage yourself or your loved one to fight the good fight and don’t give up on them.
Cancer is a complex disease that requires medical attention and emotional support. By making some lifestyle changes and getting regular screenings, you can reduce your risk of cancer or improve your chances of survival. By seeking professional help and emotional support, you can cope with the challenges of cancer or support someone who has cancer.