What Are Symptoms and Signs?

A symptom is an indication of disease, illness, injury, or that something is not right in the body. Symptoms are felt or noticed by a person, but may not easily be noticed by anyone else. For example, chills, weakness, achiness, shortness of breath, and a cough are possible symptoms of pneumonia.

A sign is also an indication that something is not right in the body. But signs are defined as observations made by a doctor, nurse, or other health care professional. Fever, rapid breathing rate, and abnormal breathing sounds heard through a stethoscope are possible signs of pneumonia.

The presence of one symptom or sign may not give enough information to suggest a cause. For example, a rash in a child could be a symptom of a number of things including poison ivy, an infectious disease like measles, an infection limited to the skin, or a food allergy. But if the rash is seen 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. In many cases, a patient's signs and symptoms do not provide enough clues by themselves to determine the cause of an illness, and medical tests such as x-rays, blood tests, or a biopsy may be needed.

How Does Cancer Produce Signs and Symptoms?

Cancer is a group of diseases that may cause almost any sign or symptom. The signs and symptoms will depend on where the cancer is, the size of the cancer, and how much it affects the surrounding organs or structures. If a cancer spreads (metastasizes), then symptoms may appear in different parts of the body.

As a cancer grows, it begins to push on nearby organs, blood vessels, and nerves. This pressure creates 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 produce early symptoms.

Sometimes, however, cancers form in places where there may be no symptoms until the cancer has grown quite large. Pancreas cancers, for example, do not usually grow large enough to be felt from the outside of the body. Some pancreatic cancers do not produce symptoms until they begin to grow around nearby nerves, causing a backache. Others grow around the bile duct, which blocks the flow of bile and leads to a yellowing of the skin known as jaundice. By the time a pancreatic cancer causes these signs or symptoms, it has usually reached an advanced stage.

A cancer may also cause symptoms such as fever, fatigue, or weight loss. This may be caused by cancer cells using up much of the body’s energy supply or releasing substances that change the body’s metabolism. Or the cancer may cause the immune system to react in ways that produce these symptoms.

Sometimes, cancer cells release substances into the bloodstream that cause symptoms not usually thought to result from cancers. For example, some cancers of the pancreas can release substances which cause blood clots to develop in veins of the legs. Some lung cancers make hormone-like substances that affect blood calcium levels, affecting nerves and muscles and causing weakness and dizziness.

How Are Signs and Symptoms Helpful?

Treatment is most successful when cancer is found as early as possible. Finding cancer early usually means it can be treated while it is 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 initial treatment is to be surgery.

A good example of the importance of detecting cancer early is melanoma skin cancer. It is easily removed if it has not yet grown deeply into the skin, and the 5-year survival rate (percentage of people living at least 5 years after diagnosis) at this stage is nearly 100%. But once melanoma has spread to other parts of the body the survival rate drops dramatically.

Sometimes people ignore symptoms either because they do not recognize the symptoms as being significant or because they are frightened by what they might mean and don’t want to seek medical help. General symptoms, such as fatigue, are more likely to have a cause other than cancer and can seem unimportant, especially if they have an obvious cause or are only temporary. In a similar way, a person may reason that a more specific symptom like a breast mass is probably a cyst that will go away by itself. But neither of these symptoms should be discounted or overlooked, especially if they have been present for a long period of time or are getting worse.

Most likely, any symptoms you may have will not be caused by cancer, but it’s important to have them checked out by your doctor, just in case. If cancer is not the cause, your doctor can help figure out what is and treat it, if needed.

In some cases it is possible to detect some cancers before symptoms occur. The American Cancer Society and other health groups encourage the early detection of certain cancers before symptoms occur by recommending a cancer-related checkup and specific tests for people who do not have any symptoms. For more information on early detection tests, see our document, "American Cancer Society Guidelines for the Early Detection of Cancer." Keep in mind, however, that these recommended tests do not diminish the importance of reporting any symptoms to your doctor.

General Cancer Signs and Symptoms

It is important to know what some of the general (non-specific) signs and symptoms of cancer are. They include unexplained weight loss, fever, fatigue, pain, and changes in the skin. Of course, it’s important to remember that having any of these does not necessarily mean that cancer is present -- there are many other conditions that can cause these signs and symptoms as well.

Unexplained weight loss: Most people with cancer will lose weight at some time with their disease. An unexplained (unintentional) weight loss of 10 pounds or more may be the first sign of cancer, particularly cancers of the pancreas, stomach, esophagus, or lung.

Fever: Fever is very common with cancer, but is more often seen in advanced disease. Almost all patients with cancer will have fever at some time, particularly if the cancer or its treatment affects the immune system and reduces resistance to infection. Less often, fever may be an early sign of cancer, such as with leukemia or lymphoma.

Fatigue: Fatigue may be a significant symptom as cancer progresses. It may occur early, however, in cancers such as with leukemia or if the cancer is causing a chronic loss of blood, as in some colon or stomach cancers.

Pain: Pain may be an early symptom with some cancers, such as bone cancers or testicular cancer. Most often, however, pain is a symptom of advanced disease.

Skin changes: In addition to cancers of the skin (see next section), some internal cancers can produce visible skin signs such as darkening (hyperpigmentation), yellowing (jaundice), reddening (erythema), itching, or excessive hair growth.

Specific Cancer Signs and Symptoms

In addition to the above general symptoms, you should be watchful for the following common symptoms, which could be an indication of cancer. Again, there may be other causes for each of these, but it is important to bring them to your doctor’s attention as soon as possible so that they can be investigated.

Change in bowel habits or bladder function: Chronic constipation, diarrhea, or a change in the size of the stool may indicate colon cancer. Pain with urination, blood in the urine, or a change in bladder function (such as more frequent or less frequent urination) could be related to bladder or prostate cancer. Any changes in bladder or bowel function should be reported to your doctor.

Sores that do not heal: Skin cancers may bleed and resemble sores that do not heal. A persistent sore in the mouth could be an oral cancer and should be dealt with promptly, especially in patients who smoke, chew tobacco, or frequently drink alcohol. Sores on the penis or vagina may either be signs of infection or an early cancer, and should not be overlooked in either case.

Unusual bleeding or discharge: Unusual bleeding can occur in either early or advanced cancer. Blood in the sputum (phlegm) may be a sign of lung cancer. Blood in the stool (or a dark or black stool) could be a sign of colon or rectal cancer. Cancer of the cervix or the endometrium (lining of the uterus) can cause vaginal bleeding. Blood in the urine is a sign of possible bladder or kidney cancer. A bloody discharge from the nipple may be a sign of breast cancer.

Thickening or lump in breast or other parts of the body: Many cancers can be felt through the skin, particularly in the breast, testicle, lymph nodes (glands), and the soft tissues of the body. A lump or thickening may be an early or late sign of cancer. Any lump or thickening should be reported to your doctor, especially if you’ve just discovered it or noticed it has grown in size. You may be feeling a lump that is an early cancer that could be treated successfully.

Indigestion or trouble swallowing: While they commonly have other causes, these symptoms may indicate cancer of the esophagus, stomach, or pharynx (throat).

Recent change in a wart or mole: Any change in color or shape, loss of definite borders, or an increase in size should be reported to your doctor without delay. The skin lesion may be a melanoma which, if diagnosed early, can be treated successfully.

Nagging cough or hoarseness: A cough that does not go away may be a sign of lung cancer. Hoarseness can be a sign of cancer of the larynx (voice box) or thyroid.

While the signs and symptoms listed above are the more common ones seen with cancer, there are many others that are less common and are not listed here. If you notice any major changes in the way your body functions or the way you feel, especially if it lasts for a long time or gets worse, let your doctor know. If it has nothing to do with cancer, your doctor can investigate it and treat it, if needed. If it is cancer, you’ll give yourself the best chance to have it treated early, when treatment is most likely to be effective.