cancer.about.comCancer: Overview and More

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Learn about our Medical Review Board Doru Paul, MD Updated on November 26, 2019 Cancer Overview Symptoms Causes Diagnosis Treatment Coping In This Article Table of Contents Expand Types Symptoms Causes Diagnosis Treatment Coping View All Cancer is a group of over 200 different diseases in which abnormal cells multiply uncontrollably, destroying body tissues or functions. The most common types are basal cell skin cancer, breast cancer, prostate cancer, lung cancer, colon cancer, melanoma, leukemia, and lymphoma. Cancer has various symptoms and is treated in different ways depending on the type. Treatments include surgery, chemotherapy, radiation, and targeted therapies. One in 2 men and 1 in 3 women are expected to develop cancer (not including skin cancer) over the course of a lifetime. Types of Cancer Each cancer is named for the tissue type or organ in which it begins. Some of these are very common, for example, 1 in 7 men are expected to develop prostate cancer. Some are very rare, occurring in only a few people each year. The top 10 most common cancers to occur other than skin cancer (incidence of new cases in men and women combined) include: Breast cancer Lung cancer Prostate cancer Colon cancer Bladder cancer Melanoma Non-Hodgkin lymphoma Thyroid Cancer Kidney cancer Leukemia While they are not in the top 10 most common for occurrence, pancreatic cancer and endometrial (uterine) cancer are in the top 10 most fatal cancers. Less common cancers that still affect a significant number of people each year in the United States include ovarian cancer , testicular cancer , brain tumors . and myeloma . There are many types of uncommon and rare cancers. Cancer Symptoms Having an awareness of the most common symptoms of cancer , and talking to your doctor if you experience any of them, is critical in taking good care of your health. Common symptoms of cancer include: A persistent cough A sore that does not heal or a mole that is changing Shortness of breath Pain ranging from head pain, to back pain, to abdominal and pelvic pain, to pain in your extremities Fatigue Unintentional weight loss Hoarseness Night sweats Difficulty swallowing Heartburn Lumps and bumps anywhere on the body, especially breast lumps or testicular lumps Enlarged lymph nodes anywhere in your body including your armpit and your groin Abdominal swelling and bloating Blood in your urine Blood in your stool Less common symptoms occur with many cancers but are no less important. Examples include jaundice, a yellowish discoloration of the skin, and even new onset depression. Talk to your doctor if you have any symptoms that are unexplained. If those symptoms remain as such after you see your doctor, it's important to go back for another visit or get a second opinion. Many cancer survivors are alive because they were their own advocates and did not settle for an unconfirmed diagnosis. Signs and Symptoms of Cancer Causes For a normal cell to become a cancer cell , a series of gene mutations needs to take place. The mechanisms leading to these mutations include: Direct damage to DNA: Some substances and exposures can directly damage the DNA in your cells. An example would be radiation or some carcinogens from the environment. Chronic inflammation: Whenever cells reproduce and divide, there is a chance that an accident (a DNA mutation) will happen. Chronic inflammation, such as that in the respiratory tree or esophagus related to smoking, may result in cancer by increasing the chance that such a mistake in cell division will occur. There are several risk factors that account for cells becoming cancer cells. These can be broken down to include: Lifestyle factors: Smoking is the single most important cause of cancer. Smoking causes many different types of cancer and is responsible for nearly a third of cancer deaths . Obesity may actually soon surpass smoking as the leading preventable cause of cancer in the U.S., and unfortunately, it's thought that only a third of Americans are aware of this risk. Excess alcohol is also associated with an increased risk of several cancers. Environmental exposures: Radon exposure causes cancer and having an elevated level of this gas in your home is the second most common cause of lung cancer. Work-related exposures to cancer-causing substances (carcinogens) is an important cause of cancer in men, but increasingly, in women as well. Genetics: A genetic predisposition to cancer can occur when people inherit a mutation in a gene responsible for removing damaged cells (tumor suppressor genes) and more. Viruses and other microorganisms: Viruses are an important cause of cancer , responsible for roughly 25% of cancers worldwide, and 5% to 10% of cancers in the U.S. Infection with human papillomavirus (HPV), for example, is the cause of most cervical cancers, as well as some other types. H. pylori is thought to be the cause of many stomach cancers in the United States. It's important to note that a cancer can be primary or secondary . For example, cancer that originates in the lung is primary lung cancer. Cancer that occurs in the lung because of cancer cells that have spread from, say, the breast is considered secondary lung cancer (a.k.a., cancer metastatic to the lung). The cancer cells in these two cases are not the same. Causes and Risk Factors of Cancer Diagnosis Screening tests are done routinely for some types of cancer, such as fecal occult blood for colon cancer, PSA test for prostate cancer, mammograms for breast cancer, and the PAP test for cervical cancer. Or, you may go to your doctor because you are having some of the symptoms of cancer. The next diagnostic steps will depend on the type of cancer. You can expect blood tests and urine tests looking at your overall health as well as high or low amounts of some substances or, in the case of blood cancers, abnormal cells. Imaging studies may be done to look for tumors. These include X-rays, CT scans, ultrasound, MRI, PET scans, and nuclear scans. When a tumor is suspected, your doctor will usually do a biopsy so cells can be analyzed to determine whether the growth is cancerous. The diagnostic process may also include staging, which determ...