Having 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 give enough clues by themselves for the doctor to figure out the cause of an illness. Then medical tests, such as x-rays, blood tests, or a biopsy may be needed.
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 nearby 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 cause early symptoms.
But sometimes cancers start in places where it does not cause any 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 cause symptoms until they begin to grow around nearby nerves (this causes 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 because cancer cells use up much of the body’s energy supply or release 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.
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 finding cancer early is melanoma skin cancer. Skin cancer can be easy to remove if it has not grown deep 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 know that the symptoms could mean something is wrong 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 only last a short time. 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 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 check-up and specific tests for people who do not have any symptoms. Keep in mind, however, that these recommended tests do not decrease the importance of reporting any symptoms to your doctor.
It is important to know what some of the general (non-specific) signs and symptoms of cancer are, but remember that having any of these does not mean that you have cancer. There are many other conditions that can cause these signs and symptoms, too. 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 is very common with cancer, but is more often seen in advanced disease. Almost all patients with cancer will have fever at some time, especially if the cancer or its treatment affects the immune system and makes it harder for the body to fight infection. Less often, fever may be an early sign of cancer, such as with leukemia or lymphoma. Fatigue may be an important symptom as cancer progresses. It may happen early, though, in cancers such as with leukemia, or if the cancer is causing an ongoing loss of blood, as in some colon or stomach cancers. Pain may be an early symptom with some cancers such as bone cancers or testicular cancer. But most often pain is a symptom of advanced disease. Along with cancers of the skin, some internal cancers can cause skin signs that can be seen. These changes include the skin looking darker (hyper pigmentation), yellow (jaundice), or red (erythema); itching; or excessive hair growth.Along with the above general symptoms, you should watch 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.
Long-term constipation, diarrhea, or a change in the size of the stool may be a sign of 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. Skin cancers may bleed and look like sores that do not heal. A long-lasting sore in the mouth could be an oral cancer and should be dealt with right away, 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.
Unusual bleeding can happen 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 may be a sign of bladder or kidney cancer. A bloody discharge from the nipple may be a sign of breast cancer. Many cancers can be felt through the skin, mostly 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.
While they commonly have other causes, indigestion or swallowing problems may be a sign of cancer of the esophagus, stomach, or pharynx (throat). Any wart, mole, or freckle that changes in color, size, or shape, or loses its definite borders should be reported to your doctor without delay. The skin lesion may be a melanoma which, if diagnosed early, can be treated successfully. 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.