What are Cancer, Breast Cancer, Prostate Cancer, Skin Cancer, Bladder Cancer, Kidney Cancer, Lung Cancer, Colorectal Cancer, Leukemia, Lymphoma, Ovarian Cancer, Uterine Cancer, Pancreatic Cancer, and Stomach Cancer?
Uterine cancer includes both cervical cancer and endometrial cancer, cancer of the lining of the uterus. Nearly 49,000 women in the United States and 5,000 women in Canada are diagnosed with uterine cancer each year. The single greatest risk factor for cervical cancer is infection with the human papilloma virus (HPV). Other risk factors include sexual intercourse before age 18, having many sexual partners, and cigarette smoking. For reasons that are not entirely clear, the disease also seems to be more common in women of low socioeconomic status.
There are two main types of cancer of the cervix, the lower part of the uterus. Squamous cell carcinomas make up 85 to 90 percent of these cancers. The other 10 to 15 percent are adenocarcinomas. Most cervical cancers develop slowly and may not produce any noticeable symptoms in the early stages. As the cancer progresses, the woman may experience a watery vaginal discharge and painless bleeding. Over time, the bleeding becomes heavier and more frequent, and pain becomes noticeable in the lower abdomen or back. The five-year survival rate for cervical cancer in the United States is 71 percent but rises to 91 percent if the cancer is detected early. For unknown reasons, black women are twice as likely to die of the disease than are white women in the United States.
There are two main types of cancer of the cervix, the lower part of the uterus. Squamous cell carcinomas make up 85 to 90 percent of these cancers. The other 10 to 15 percent are adenocarcinomas. Most cervical cancers develop slowly and may not produce any noticeable symptoms in the early stages. As the cancer progresses, the woman may experience a watery vaginal discharge and painless bleeding. Over time, the bleeding becomes heavier and more frequent, and pain becomes noticeable in the lower abdomen or back. The five-year survival rate for cervical cancer in the United States is 71 percent but rises to 91 percent if the cancer is detected early. For unknown reasons, black women are twice as likely to die of the disease than are white women in the United States.
Nearly all endometrial cancers are adenocarcinomas. The risk of developing endometrial cancer is higher in women who take certain hormones during estrogen replacement therapy. Other risk factors include early onset of menstruation and late menopause, probably because these factors increase the number of years during which the endometrium is exposed to estrogen and other steroid hormones. Obesity also increases the risk of endometrial cancer, probably because excess fat can increase the level of estrogens in a woman’s body. Excess weight of 14 kg (30 lb) triples a woman's endometrial cancer risk. Similarly, diseases more common in women who are overweight, including diabetes mellitus and gallbladder disease, are also associated with a higher risk of endometrial cancer.
Endometrial cancer symptoms are similar to those of cervical cancer. Most often, they start with a watery vaginal discharge that has streaks of blood. In the United States, the five-year survival rate for endometrial cancer is 83 percent but climbs to 96 percent if the cancer is caught and treated at an early stage.
Diagnosis of cancer often begins when a person notices an unusual health symptom and consults a doctor. Early warning signs of cancer include changes in bowel or bladder habits, a sore that does not heal, unusual bleeding or discharge, thickening or a lump in the breast or any other part of the body, indigestion or difficulty swallowing, change in appearance of a wart or mole, or a nagging cough or hoarseness.
Diagnosis of cancer often begins when a person notices an unusual health symptom and consults a doctor. Early warning signs of cancer include changes in bowel or bladder habits, a sore that does not heal, unusual bleeding or discharge, thickening or a lump in the breast or any other part of the body, indigestion or difficulty swallowing, change in appearance of a wart or mole, or a nagging cough or hoarseness.
Detection
Mammogram Mammography is a special X-ray technique that is used to visualize soft tissues of the breast as a means for screening women for breast cancer. This mammogram shows calcification (dense white flecks) in a cancerous tumor. The nipple is to the left. The majority of breast cancers originate in the duct of the mammary, or milk-secreting, gland. The remainder arise in the glands themselves. Most tumors of either type show early evidence of invasive (malignant) behavior, but both may also exist in noninvasive forms.Photo Researchers, Inc./Kings College Hospital/Science Source
People with early warning signs should consult their family doctor, who will evaluate symptoms and may refer the patient to a physician who specializes in cancer. A physician will first take the patient’s medical history to learn about current symptoms, past history of disease, and family members diagnosed with cancer. The procedures used in a physical exam depend on the patient’s clinical symptoms and may include a digital rectal examination, in which the physician uses a gloved finger to gently check the smoothness of the rectal lining. The physician may perform a breast exam on female patients, in which the breasts are gently probed to feel for lumps or unusual masses.
Thermogram Because the temperature of human skin changes in response to disorders in the underlying tissue, conditions such as poor circulation, swelling, and cancer are visible with cameras sensitive to infrared heat. In this thermogram, cancerous tissue (yellow) contrasts with the rest of the body’s blue and green coloration.Phototake NYC/CNRI
During the examination the physician may use a thin, lighted tube called an endoscope to look for tumors in internal body cavities. The endoscopy procedure used depends on the organ or body cavity examined. In gastric endoscopy, the doctor feeds a specialized endoscope down the throat to examine the lining of the esophagus, stomach, and first part of the small intestine. Fiberoptic sigmoidoscopy, in which a flexible instrument is inserted into the lower intestinal tract through the anus, enables a physician to visually examine the interior of the colon and rectum. Colonoscopy uses a much longer flexible instrument to view the entire length of the large intestine.
Cervical Cells Healthy cervical cells (left) are fairly uniform in size and shape, while diseased cervical cells (right) are irregular and disfigured. Gynecologists use a Pap smear to detect abnormalities in cervical cells, which may signal cancer. Cells are scraped from the cervix, and then are spread on slides and studied with a microscope.Photo Researchers, Inc./Martin M. Rotker/AFIP/Science Source
A number of laboratory tests help narrow the possible diagnoses. In a Pap smear, cells are removed from the cervical epithelium with a small plastic brush. These cells are examined under a microscope for cell changes that are a sign that cancer may be developing as well as signs of malignancy. If a patient’s clinical signs suggest colorectal cancer, the doctor may search for blood in the stool using a fecal occult blood test. A small sample of the patient’s stool is smeared on a card coated with a chemical called guaiac, which reacts with blood. The card is analyzed in a laboratory for occult (hidden) blood. Certain blood tests determine if levels of red and white blood cells are low, a possible indication of leukemia. Others test for the presence of tumor markers, chemicals that are present in higher levels when certain cancers are present. For example, a prostate-specific antigen (PSA) test measures levels of prostate-specific antigen in the blood. Prostate cancer cells overproduce this protein, causing an elevation of PSA levels in blood.
Medical imaging techniques help doctors locate and evaluate a tumor. These include computed tomography (CT) and magnetic resonance imaging (MRI) scans. CT and MRI scans use computers to form a three-dimensional image of the tumor and surrounding tissues. X-ray images of the breast called mammograms help physicians detect and evaluate breast cancer. Ultrasound scanning bounces high-frequency sound waves off a tumor and surrounding tissue to create an image of the tumor. The multimodality display technique combines the images from several imaging tools into one picture, providing a final three-dimensional image with much greater detail. Computer-aided diagnosis uses complex computer programming technology called artificial intelligence to scan mammograms and X rays to help look for signs of cancer and offer an automated second opinion.
Staging
When a tumor is detected, the physician takes a biopsy by removing a sample of the tissue. The biopsy sample is inspected under a microscope to determine if the tumor is benign or malignant. Cancerous cells usually appear abnormal in shape and no longer orient themselves in orderly configurations. If the tumor is cancerous, the physician assigns it a stage, indicating how far cancer has spread. The stage is a key factor in determining both the cancer’s treatment and prognosis. Oncologists, physicians who specialize in the diagnosis and treatment of cancer, use several different staging systems. In one system, tumors are grouped into four stages denoted by Roman numerals I through IV. Stage I cancers are small localized cancers that are usually curable. Stage II and III tumors are usually locally advanced and may or may not have invaded nearby lymph nodes, and stage IV tumors have usually metastasized—that is, spread to distant tissues in the body.
The most widely used staging system is the Tumor, Lymph Node, and Metastasis system, commonly abbreviated TNM. This system uses numbers between zero and three to assess the size of the tumor (T), the extent that it has spread to nearby lymph nodes (N), and the extent that it has spread throughout the body (M). A cancer’s stage depends on a combination of these numbers. For example, a T-1, N-0, and M-0 tumor is a stage 1 tumor. This tumor is 2 cm (1 in) or less (T-1) and has not spread to nearby lymph nodes (accounting for N-0) or metastasized (M-0). The five-year survival rate for a patient with this stage tumor is accordingly excellent. A T-3, N-1, and M-0 tumor is a stage 3 tumor. This tumor is greater than 5 cm (2 in) and has spread to nearby lymph nodes, but there is no evidence that the cancer has spread to distant tissues. The five-year survival rate for a patient with this tumor is not as high as the T-1, N-0, M-0 patient. Stage 4 tumors are distinguished by an M-1 number. This means they have progressed to the point where metastasis is widespread, and the prognosis is usually quite poor.
When a tumor is detected, the physician takes a biopsy by removing a sample of the tissue. The biopsy sample is inspected under a microscope to determine if the tumor is benign or malignant. Cancerous cells usually appear abnormal in shape and no longer orient themselves in orderly configurations. If the tumor is cancerous, the physician assigns it a stage, indicating how far cancer has spread. The stage is a key factor in determining both the cancer’s treatment and prognosis. Oncologists, physicians who specialize in the diagnosis and treatment of cancer, use several different staging systems. In one system, tumors are grouped into four stages denoted by Roman numerals I through IV. Stage I cancers are small localized cancers that are usually curable. Stage II and III tumors are usually locally advanced and may or may not have invaded nearby lymph nodes, and stage IV tumors have usually metastasized—that is, spread to distant tissues in the body.
The most widely used staging system is the Tumor, Lymph Node, and Metastasis system, commonly abbreviated TNM. This system uses numbers between zero and three to assess the size of the tumor (T), the extent that it has spread to nearby lymph nodes (N), and the extent that it has spread throughout the body (M). A cancer’s stage depends on a combination of these numbers. For example, a T-1, N-0, and M-0 tumor is a stage 1 tumor. This tumor is 2 cm (1 in) or less (T-1) and has not spread to nearby lymph nodes (accounting for N-0) or metastasized (M-0). The five-year survival rate for a patient with this stage tumor is accordingly excellent. A T-3, N-1, and M-0 tumor is a stage 3 tumor. This tumor is greater than 5 cm (2 in) and has spread to nearby lymph nodes, but there is no evidence that the cancer has spread to distant tissues. The five-year survival rate for a patient with this tumor is not as high as the T-1, N-0, M-0 patient. Stage 4 tumors are distinguished by an M-1 number. This means they have progressed to the point where metastasis is widespread, and the prognosis is usually quite poor.
