Cancer Symptoms

Signs and symptoms caused by cancer will vary depending on what part of the body is affected. Some general signs and symptoms associated with, but not specific to, cancer include: 
  • Fatigue
  • Lump or thickening that can be felt under the skin
  • Weight changes, including unintended loss or gain
  • Skin changes, such as yellowing, darkening or redness of the skin, sores that won't heal, or changes to existing moles
  • Changes in bowel or bladder habits
  • Persistent cough
  • Difficulty swallowing
  • Hoarseness
  • Persistent indigestion or discomfort after eating
  • Persistent, unexplained muscle or joint pain
  • Unexplained and persistent fevers or night sweats
 
When to see a doctor 
Make an appointment with your doctor if you have any persistent signs or symptoms that concern you. 
If you don't have any signs or symptoms, but are worried about your risk of cancer, discuss your concerns with your doctor. Ask about which cancer screening tests and procedures are appropriate for you. 
 

Causes

Cancer is caused by changes (mutations) to the DNA within cells. The DNA inside a cell contains a set of instructions telling the cell how to grow and divide. Errors in the instructions may allow a cell to become cancerous. 
 
What do gene mutations do? 
A gene mutation can instruct a healthy cell to: 
  • Allow rapid growth. A gene mutation can tell a cell to grow and divide more rapidly. This creates many new cells that all have that same mutation. 
  • Fail to stop uncontrolled cell growth. Normal cells contain genes called tumor suppressor genes that recognize out-of-control growth and act to stop it. But if a mutation occurs in a tumor suppressor gene, that gene may become less effective or may be turned off completely. This allows a mutated cell to continue growing and dividing.
  • Make mistakes when repairing DNA errors. DNA repair genes identify and correct DNA mutations. A mutation in a DNA repair gene means that the gene may miss some DNA errors. This allows more DNA mutations to occur and may lead to cancer.
 
These mutations are the most common ones found in cancer. But many other gene mutations can contribute to causing cancer. 
 
What causes gene mutations? 
Sometimes you're born with a genetic mutation. Or a genetic mutation can be caused by forces within your body, such as hormones, viruses and chronic inflammation. Genetic mutations can also be caused by forces outside of your body, such as ultraviolet (UV) light from the sun, cancer-causing chemicals (carcinogens) or radiation. 
 
How do gene mutations interact with each other? 
Researchers believe that more than one gene mutation is necessary to cause most cancers. Some blood cancers may require just one gene mutation to drive their growth. Most cancers that form in the body's major organs, such as the lungs and the colon, have many gene mutations. It's not clear just how many mutations must accumulate for cancer to form. It's likely that this varies among cancer types. 
 
The gene mutations you're born with and those that you acquire throughout your life work together to cause cancer. For instance, if you've inherited a genetic mutation that predisposes you to cancer, that doesn't mean you're certain to get cancer. Instead, you may need one or more other gene mutations to cause cancer. Your inherited gene mutation could make you more likely than other people to develop cancer when exposed to a certain cancer-causing substance. The genetic mutation begins the cancer process, and the cancer-causing substance could play a role in further cancer development. 
 

Risk factors

While doctors have an idea of what may increase your risk of cancer, the majority of cancers occur in people who don't have any known risk factors. Factors known to increase your risk of cancer include: 
 
Your age 
Cancer can take decades to develop. That's why most people diagnosed with cancer are 65 or older. While it's more common in older adults, cancer isn't exclusively an adult disease — cancer can be diagnosed at any age. 
 
Your habits 
Certain lifestyle choices are known to increase your risk of cancer. Smoking, drinking more than one drink a day (for women) or two drinks a day (for men), excessive exposure to the sun or frequent blistering sunburns, and having unsafe sex can contribute to cancer. You can change these habits to lower your risk of cancer — though some habits are easier to change than others. 
 
Your family history 
Only a small portion of cancers are due to an inherited condition. If cancer is common in your family, it's possible that mutations are being passed from one generation to the next. You might be a candidate for genetic testing to see whether you have inherited mutations that might increase your risk of certain cancers. Keep in mind that having an inherited genetic mutation doesn't necessarily mean you'll get cancer. 
 
Your health conditions 
Some chronic health conditions, such as ulcerative colitis, can markedly increase your risk of developing certain cancers. Talk to your doctor about your risk. 
 
Your environment 
The environment around you may contain harmful chemicals that can increase your risk of cancer. Even if you don't smoke, you might inhale secondhand smoke if you go where people are smoking or you live with someone who smokes. Chemicals in your home or workplace, such as asbestos and benzene, also are associated with an increased risk of cancer.