What are signs and symptoms?
Signs and symptoms are both signals of injury, illness, disease – signals that something is not right in the body.
A sign is a signal that can be seen by someone else – maybe a loved one, or a doctor, nurse, or other health care professional. For example, fever, fast breathing, and abnormal lung sounds heard through a stethoscope may be signs of pneumonia.
A symptom is a signal that’s felt or noticed by the person who has it, but may not be easily seen by anyone else. For example, weakness, aching, and feeling short of breath may be symptoms of pneumonia.
Having one sign or symptom may not be enough to figure out what’s causing it. For example, a rash in a child could be a sign of a number of things, such as poison ivy, measles, a skin infection, or a food allergy. But if the child has the rash along with other signs and symptoms like a high fever, chills, achiness, and a sore throat, then a doctor can get a better picture of the illness. Sometimes, a patient’s signs and symptoms still don’t give the doctor enough clues to be sure what’s causing the illness. Then medical tests, such as x-rays, blood tests, or a biopsy may be needed.
How does cancer cause signs and symptoms?
Cancer is a group of diseases that can cause almost any sign or symptom. The signs and symptoms will depend on where the cancer is, how big it is, and how much it affects the organs or tissues. If a cancer has spread (metastasized), signs or symptoms may appear in different parts of the body.
As a cancer grows, it can begin to push on nearby organs, blood vessels, and nerves. This pressure causes some of the signs and symptoms of cancer. If the cancer is in a critical area, such as certain parts of the brain, even the smallest tumor can cause symptoms.
But sometimes cancer starts in places where it won’t cause any signs or symptoms until it has grown quite large. Cancers of the pancreas, for example, usually don’t cause symptoms until they grow large enough to press on nearby nerves or organs (this causes back or belly pain). Others may grow around the bile duct and block the flow of bile. This causes the eyes and skin to look yellow (jaundice). By the time a pancreatic cancer causes signs or symptoms like these, it’s usually in an advanced stage. This means it has grown and spread beyond the place it started – the pancreas.
A cancer may also cause symptoms like fever, extreme tiredness (fatigue), or weight loss. This may be because cancer cells use up much of the body’s energy supply, or they may release substances that change the way the body makes energy from food. Cancer can also cause the immune system to react in ways that produce these signs and symptoms.
Sometimes, cancer cells release substances into the bloodstream that cause symptoms that are not usually linked to cancer. For example, some cancers of the pancreas can release substances that cause blood clots in veins of the legs. Some lung cancers make hormone-like substances that raise blood calcium levels. This affects nerves and muscles, making the person feel weak and dizzy.
How are signs and symptoms helpful?
Treatment works best when cancer is found early – while it’s still small and is less likely to have spread to other parts of the body. This often means a better chance for a cure, especially if the cancer can be removed with surgery.
A good example of the importance of finding cancer early is melanoma skin cancer. It can be easy to remove if it has not grown deep into the skin. The 5-year survival rate (percentage of people who live at least 5 years after diagnosis) at this early stage is around 98%. Once melanoma has spread to other parts of the body, the 5-year survival rate drops to about 16%.
Sometimes people ignore symptoms. Maybe they don’t know that the symptoms could mean something is wrong. Or they might be frightened by what the symptoms could mean and don’t want to get medical help. Maybe they just can’t afford to get medical care.
Some symptoms, such as tiredness or coughing, are more likely caused by something other than cancer. Symptoms can seem unimportant, especially if there’s a clear cause or the problem only lasts a short time. In the same way, a person may reason that a symptom like a breast lump is probably a cyst that will go away by itself. But no symptom should be ignored or overlooked, especially if it has lasted a long time or is getting worse.
Most likely, symptoms are not caused by cancer, but it’s important to have them checked out, just in case. If cancer is not the cause, a doctor can help figure out what the cause is and treat it, if needed.
Sometimes, it’s possible to find cancer before having symptoms. The American Cancer Society and other health groups recommend cancer-related check-ups and certain tests for people even though they have no symptoms. This helps find certain cancers early, before symptoms start. For more information on early detection tests, see our document called American Cancer Society Guidelines for the Early Detection of Cancer. But keep in mind, even if you have these recommended tests, it’s still important to see a doctor if you have any symptoms.
What are some general signs and symptoms of cancer?
You should know some of the general signs and symptoms of cancer. But remember, having any of these does not mean that you have cancer – many other things cause these signs and symptoms, too. If you have any of these symptoms and they last for a long time or get worse, please see a doctor to find out what’s going on.
Unexplained weight loss
Most people with cancer will lose weight at some point. When you lose weight for no known reason, it’s called an unexplained weight loss. An unexplained weight loss of 10 pounds or more may be the first sign of cancer. This happens most often with cancers of the pancreas, stomach, esophagus (swallowing tube), or lung.
Fever is very common with cancer, but it more often happens after cancer has spread from where it started. Almost all people with cancer will have fever at some time, especially if the cancer or its treatment affects the immune system. (This can make it harder for the body to fight infection.) Less often, fever may be an early sign of cancer, such as blood cancers like leukemia or lymphoma.
Fatigue is extreme tiredness that doesn’t get better with rest. It may be an important symptom as cancer grows. But it may happen early in some cancers, like leukemia. Some colon or stomach cancers can cause blood loss that’s not obvious. This is another way cancer can cause fatigue.
Pain may be an early symptom with some cancers like bone cancers or testicular cancer. A headache that does not go away or get better with treatment may be a symptom of a brain tumor. Back pain can be a symptom of cancer of the colon, rectum, or ovary. Most often, pain due to cancer means it has already spread (metastasized) from where it started.
Along with skin cancers, some other cancers can cause skin changes that can be seen. These signs and symptoms include:
- Darker looking skin (hyperpigmentation)
- Yellowish skin and eyes (jaundice)
- Reddened skin (erythema)
- Itching (pruritis)
- Excessive hair growth
Signs and symptoms of certain cancers
Along with the general symptoms, you should watch for certain other common signs and symptoms that could suggest cancer. Again, there may be other causes for each of these, but it’s important to see a doctor about them as soon as possible – especially if there’s no other cause you can identify, the problem lasts a long time, or it gets worse over time.
The signs and symptoms listed above are the more common ones seen with cancer, but there are many others that are not listed here. If you notice any major changes in the way your body works or the way you feel – especially if it lasts for a long time or gets worse – let a doctor know. If it has nothing to do with cancer, the doctor can find out more about what’s going on and, if needed, treat it. If it is cancer, you’ll give yourself the chance to have it treated early, when treatment works best.