Cancer is a disease in which the cells in part of a person’s body grow uncontrollably. Although there a many different types of cancer, they all develop as a result of uncontrolled growth of abnormal malignant cells. Normally, cells grow, divide and die in an orderly way. The rates of new cell growth and old cell death are kept in balance. In a healthy person, the cells divide at a rate to repair injuries and to replace depleted or dying cells, while the old and damaged cells self-destruct in a process known as apoptosis.
This normal balance is disrupted during the development of cancer. Cancer cells continue to grow and divide uncontrollably, outliving normal cells and continuing to form new abnormal cells. This increase in cell division generates a growing mass of tissue known as a tumor or neoplasm. As new cells are being produced in greater numbers than needed by the body, the tumor will increase in size. The growth rate of a tumor depends on the rate of cell division. When cells divide rapidly, the tumor will grow quickly and vice versa.
Typically, cancer forms as a tumor. However, not all tumors are malignant. Noncancerous or benign tumors do not spread and are normally not life threatening. Some types of cancer do not involve tumor masses in one place, but are diffused throughout the body. An example is the leukemias, which involve the blood and blood-forming organs.
Frequently, cancer cells travel from the initial tumor to other areas of the body where they begin to grow and replace healthy tissue. There are two main terms used to describe the spread of cancer from its original location:
Invasion. Cancer cells invade neighboring tissues. For example, invasive cancer cells in the breast may penetrate into tissues within or near the breast. Metastasis. Cancer spreads beyond the immediate neighboring area to other body areas. It may penetrate the lymph vessels and blood vessels, enter the bloodstream and invade normal tissue in adjacent and distant areas of the body. The likelihood that cancer will metastasize depends on the type of cancer and its stage. Although each patient’s case is unique, some types of cancer have a tendency to spread to certain areas, including the lungs, bones and brain.
Cancer can develop almost anywhere in the body. Although it may spread to other parts of the body, it is always named for the area where it originated. For example, melanoma (cancer of the cells that produce skin coloring) that spreads to the liver is classified as metastatic melanoma, not liver cancer
Fatigue is one of the most commonly experienced cancer symptom. It is usually more common when the cancer is advanced, but still occurs in the early stages.
Losing 10 or more pounds without dieting or intending to lose weight can be one of the first symptoms experienced with cancer.
Most cancer patients experience a fever at some point. It may be due to the disease affecting their immune system, the cancer itself, or a response to treatment.
Skin changes such as jaundice, darkening of the skin, abnormal hair growth, reddening, and skin itchiness can indicate certain types of cancers.
Pain is normally present when the cancer has progressed. However, it can be indicative early on of some cancers, such as bone cancers
Tobacco is the single largest preventable cause of cancer in the world today. It causes 80-90% of all lung cancer deaths, and about 30% of all cancer deaths in developing countries, including deaths from cancer of the oral cavity, larynx, oesophagus and stomach.
Dietary modification is another important approach to cancer control. There is a link between overweight and obesity to many types of cancer such as oesophagus, colorectum, breast, endometrium and kidney. Diets high in fruits and vegetables may have a protective effect against many cancers.
Regular physical activity and the maintenance of a healthy body weight, along with a healthy diet, will considerably reduce cancer risk.
Infectious agents are responsible for almost 22% of cancer deaths in the developing world and 6% in industrialized countries. Viral hepatitis B and C cause cancer of the liver; human papilloma virus infection causes cervical cancer; the bacterium Helicobacter pylori increases the risk of stomach cancer.
Exposure to ionizing radiation is also known to cause to certain cancers. Excessive solar ultraviolet radiation increases the risk of all types of cancer of the skin. Avoiding excessive exposure, use of sunscreen and protective clothing are effective preventive measures.
Asbestos can cause lung cancer; aniline dyes have been linked to bladder cancer; and benzene can lead to leukaemia. The prevention of certain occupational and environmental exposure to these and other chemicals is another important element in preventing cancer.
The doctor can remove samples of tissue with the cystoscope. A pathologist then examines the tissue under a microscope. The removal of tissue to look for cancer cells is called a biopsy. In many cases, a biopsy is the only sure way to tell whether cancer is present. For a small number of patients, the doctor removes the entire cancerous area during the biopsy. For these patients, bladder cancer is diagnosed and treated in a single procedure.
One of the following types of surgery may be done:
Even if the doctor removes all the cancer that can be seen at the time of the surgery, some patients may be given chemotherapy after surgery to kill any cancer cells that are left. Treatment given after surgery, to increase the chances of a cure, is called adjuvant therapy.
Your doctor may ask about your personal and family medical history. You may have a physical exam. Your doctor also may order a mammogram or other imaging procedure such as Ultrasound or Magnetic Resonance Imaging. These tests make pictures of tissues inside the breast. After the tests, your doctor may decide no other exams are needed. Your doctor may suggest that you have a follow-up exam later on. Or you may need to have a biopsy to look for cancer cells.
Doctors can remove tissue from the breast in different ways:
Surgery is the most common treatment for breast cancer. There are several types of surgery.
The surgeon often removes the underarm lymph nodes as well. A separate incision is made. This procedure is called an axillary lymph node dissection. It shows whether cancer cells have entered the lymphatic system.
Sentinel lymph node biopsy is a new method of checking for cancer cells in the lymph nodes. A surgeon removes fewer lymph nodes, which causes fewer side effects. (If the doctor finds cancer cells in the axillary lymph nodes, an axillary lymph node dissection usually is done.)
Doctors use two types of radiation therapy to treat breast cancer. Some women receive both types:
Chemotherapy uses anticancer drugs to kill cancer cells. Chemotherapy for breast cancer is usually a combination of drugs. The drugs may be given as a pill or by injection into a vein (IV). Either way, the drugs enter the bloodstream and travel throughout the body.
Some breast tumors need hormones to grow. Hormone therapy keeps cancer cells from getting or using the natural hormones they need. These hormones are estrogen and progesterone. Lab tests can show if a breast tumor has hormone receptors. If you have this kind of tumor, you may have hormone therapy.
This treatment uses drugs or surgery:
Some women with breast cancer that has spread receive a biological therapy called trastuzumab. It is a monoclonal antibody. It is made in the laboratory and binds to cancer cells.
Trastuzumab is given to women whose lab tests show that a breast tumor has too much of a specific protein known as HER2
A common symptom of colorectal cancer is a change in bowel habits. Symptoms include:
If your physical exam and test results do not suggest cancer, your doctor may decide that no further tests are needed and no treatment is necessary. However, your doctor may recommend a schedule for checkups. If tests show an abnormal area (such as a polyp), a biopsy to check for cancer cells may be necessary. Often, the abnormal tissue can be removed during colonoscopy or sigmoidoscopy. A pathologist checks the tissue for cancer cells using a microscope.
Surgery is the most common treatment for colorectal cancer.
When a section of your colon or rectum is removed, the surgeon can usually reconnect the healthy parts. However, sometimes reconnection is not possible. In this case, the surgeon creates a new path for waste to leave your body. The surgeon makes an opening (stoma) in the wall of the abdomen, connects the upper end of the intestine to the stoma, and closes the other end. The operation to create the stoma is called a colostomy. A flat bag fits over the stoma to collect waste, and a special adhesive holds it in place.
For most people, the stoma is temporary. It is needed only until the colon or rectum heals from surgery. After healing takes place, the surgeon reconnects the parts of the intestine and closes the stoma. Some people, especially those with a tumor in the lower rectum, need a permanent stoma.
Chemotherapy for colorectal cancer can cause the skin on the palms of the hands and bottoms of the feet to become red and painful. The skin may peel off.
Your health care team can suggest ways to control many of these side effects. Most side effects usually go away after treatment ends.
Doctors use two types of radiation therapy to treat breast cancer. Some women receive both types:
Some people with colorectal cancer that has spread receive a monoclonal antibody, a type of biological therapy. The monoclonal antibodies bind to colorectal cancer cells. They interfere with cancer cell growth and the spread of cancer. People receive monoclonal antibodies through a vein.
Radiation therapy (also called radiotherapy) uses high-energy rays to kill cancer cells. It affects cancer cells only in the treated area.
Doctors use different types of radiation therapy to treat cancer. Sometimes people receive two types:
(IORT): In some cases, radiation is given during surgery
Common symptoms of kidney cancer include:
Physical exam: The doctor checks general signs of health and tests for fever and high blood pressure. The doctor also feels the abdomen and side for tumors.
Surgery is the most common treatment for kidney cancer. It is a type of local therapy. It treats cancer in the kidney and the area close to the tumor.
An operation to remove the kidney is called a nephrectomy. There are several types of nephrectomies. The type depends mainly on the stage of the tumor. The doctor can explain each operation and discuss which is most suitable for the patient:
Radical nephrectomy: Kidney cancer is usually treated with radical nephrectomy. The surgeon removes the entire kidney along with the adrenal gland and some tissue around the kidney. Some lymph nodes in the area also may be removed.
Arterial embolization is a type of local therapy that shrinks the tumor. Sometimes it is done before an operation to make surgery easier. When surgery is not possible, embolization may be used to help relieve the symptoms of kidney cancer.
The doctor inserts a narrow tube (catheter) into a blood vessel in the leg. The tube is passed up to the main blood vessel (renalartery) that supplies blood to the kidney. The doctor injects a substance into the blood vessel to block the flow of blood into the kidney. The blockage prevents the tumor from getting oxygen and other substances it needs to grow.
Radiation therapy (also called radiotherapy) is another type of local therapy. It uses high-energy rays to kill cancer cells. It affects cancer cells only in the treated area. A large machine directs radiation at the body. The patient has treatment at the hospital or clinic, 5 days a week for several weeks.
A small number of patients have radiation therapy before surgery to shrink the tumor. Some have it after surgery to kill cancer cells that may remain in the area. People who cannot have surgery may have radiation therapy to relieve pain and other problems caused by the cancer.
Biological therapy is a type of systemic therapy. It uses substances that travel through the bloodstream, reaching and affecting cells all over the body. Biological therapy uses the body's natural ability (immune system) to fight cancer.
For patients with metastatic kidney cancer, the doctor may suggest interferon alpha or interleukin-2 (also called IL-2 ). The body normally produces these substances in small amounts in response to infections and other diseases. For cancer treatment, they are made in the laboratory in large amounts.
Some people with colorectal cancer that has spread receive a monoclonal antibody, a type of biological therapy. The monoclonal antibodies bind to colorectal cancer cells. They interfere with cancer cell growth and the spread of cancer. People receive monoclonal antibodies through a vein.
Chemotherapy is also a type of systemic therapy. Anticancer drugs enter the bloodstream and travel throughout the body. Although useful for many other cancers, anticancer drugs have shown limited use against kidney cancer.
Early lung cancer often does not cause symptoms. But as the cancer grows, common symptoms may include:
The only sure way to know if lung cancer is present is for a pathologist to check samples of cells or tissue.
Your doctor may order one or more of the following tests to collect samples:
Surgery for lung cancer removes the tissue that contains the tumor. The surgeon also removes nearby lymph nodes.
The surgeon removes part or all of the lung:
After lung surgery, air and fluid collect in the chest. A chest tube allows the fluid to drain. Also, a nurse or respiratory therapist will teach you coughing and breathing exercises. You'll need to do the exercises several times a day.
Radiation therapy (also called radiotherapy) uses high-energy rays to kill cancer cells. It affects cells only in the treated area. You may receive external radiation. This is the most common type of radiation therapy for lung cancer. The radiation comes from a large machine outside your body. Most people go to a hospital or clinic for treatment. Treatments are usually 5 days a week for several weeks.
The side effects depend mainly on the type of radiation therapy, the dose of radiation, and the part of your body that is treated. External radiation therapy to the chest may harm the esophagus, causing problems with swallowing. You may also feel very tired. In addition, your skin in the treated area may become red, dry, and tender. After internal radiation therapy, a person may cough up small amounts of blood.
Chemotherapy is given in cycles. You have a rest period after each treatment period. The length of the rest period and the number of cycles depend on the anticancer drugs used.
Targeted therapy uses drugs to block the growth and spread of cancer cells. The drugs enter the bloodstream and can affect cancer cells all over the body. Some people with non-small cell lung cancer that has spread receive targeted therapy.
A man with prostate cancer may not have any symptoms. For men who have symptoms of prostate cancer, common symptoms include:
Your doctor will ask about your personal and family medical history. You will have a physical exam. You may have lab tests. Your visit may include a digital rectal exam, a urine test to check for blood or infection, and a blood test to measure PSA level.
You also may have other exams:
Surgery is a common treatment for early stage prostate cancer. Your doctor may remove the whole prostate or only part of it. In some cases, your doctor can use a method known as nerve-sparing surgery. This type of surgery may save the nerves that control erection. But if you have a large tumor or a tumor that is very close to the nerves, you may not be able to have this surgery.
Each type of surgery has benefits and risks. Your doctor can further describe these types:
After surgery, the urethra needs time to heal. You will have a catheter. A catheter is a tube put through the urethra into the bladder to drain urine. You will have the catheter for 5 days to 3 weeks. Your nurse or doctor will show you how to care for it.
Doctors use two types of radiation therapy to treat prostate cancer. Some men receive both types:
Hormone therapy keeps prostate cancer cells from getting the male hormones (androgens) they need to grow. The testicles are the body's main source of the male hormone testosterone. The adrenal gland makes a small amount of testosterone.
Hormone treatment uses drugs or surgery: