How Does Cancer Cause Signs and Symptoms?
When cancer grows, it can push on nearby organs, nerves, and blood vessels, which can cause signs and symptoms. Even the smallest tumors can cause symptoms in certain organs, such as the brain.
If your cancer spreads, or metastasizes, you may notice signs or symptoms in different parts of your body.
Another reason you may experience symptoms is that cancer cells use up a lot of your body’s energy supply. They also cause changes in how your immune system works. (1)
Some of the Most Common Signs and Symptoms of Cancer
Although every case is different, some general signs and symptoms of cancer include:
- Weight loss Unexplained weight loss of 10 pounds or more may be one of the first signs of cancer. Weight loss is common in people who have pancreatic, stomach, esophageal, or lung cancer, but can occur with any type of cancer. (1,2)
- Fever Fevers frequently crop up when a cancer has metastasized. Night sweats often accompany the fevers. Nearly all people with cancer will experience a fever at some point. (1,2)
- Fatigue Feeling extremely tired can be a symptom of cancer in your body. (1,2)
- A lump A lump or thickening of skin can be an early or late sign of cancer. People with cancers in the breast, lymph nodes, soft tissues, and testicles typically have lumps. (1,2)
- Skin changes Yellowing, darkening, or redness of the skin can signal cancer. Also, sores that don’t heal should be checked out. Additionally, moles, freckles, or warts that change in color, shape, or size could be a sign of skin cancer. (1,2)
- Pain Most of the time, pain happens because the cancer has already spread in your body. But pain may be an early symptom of bone cancer or testicular cancer. Back pain is common in people with colorectal cancer, pancreatic cancer, or ovarian cancer. Those with brain tumors often complain of a headache that doesn’t go away. (1,2)
- Bowel or bladder function changes Constipation, diarrhea, and other bowel issues may be a sign of colorectal cancer. People with bladder cancer and prostate cancer may report pain during urination, blood in the urine, or other bladder-function changes. (1,2)
- Cough or hoarseness A cough that doesn’t go away or a hoarse voice may be a sign of lung cancer, cancer of the larynx, or thyroid cancer. (1,2)
- Indigestion Indigestion or problems swallowing can be a sign of stomach, esophageal, or throat cancer. (1,2)
- Bleeding Unusual bleeding is associated with many different cancers. Coughing up blood may signal lung cancer. Bloody stools could be a sign of colon or rectal cancer. Women with cervical or endometrial cancer may experience abnormal vaginal bleeding. Blood in the urine could mean you have bladder or kidney cancer. Bloody discharge from a woman’s nipple might indicate breast cancer. (1,2)
- Changes in your mouth White patches inside your mouth or on your tongue could be precancers that can turn into oral cancer. Sores, bleeding, or numbness in the mouth may also be a sign of certain cancers. (1,2)
- Swollen lymph nodes Sometimes, enlarged lymph nodes can signal cancer. You should have your doctor check it out if your gland remains swollen for three to four weeks. (1,2)
- Being out of breath Constantly feeling out of breath may be a sign of certain cancers. (1,2)
- Bloating A constant uncomfortable feeling of fullness that lasts daily for weeks could be a sign of ovarian cancer. (3)
- Anemia Several cancers, including leukemia and lymphoma, can cause anemia (low red blood cell counts). These abnormal levels show up on blood tests. Having anemia can make you feel tired and weak. (4)
Most of the time, these symptoms aren’t caused by cancer. A benign tumor or another problem may be the culprit. But you shouldn’t ignore symptoms that are persistent, severe, or don’t go away.
Clues That Your Cancer Has Spread
Symptoms may be different or more intense if your cancer has metastasized to other parts of your body.
Here are some common symptoms of cancer that has spread:
- Bone metastasis Cancer that has spread to the bones may cause joint pain or fractures.
- Liver metastasis If your disease has invaded your liver, you might experience jaundice and swelling in your abdomen.
- Brain metastasis When cancer metastasizes to the brain, symptoms may include headaches, speech difficulties, blurred vision, or dizziness.
- Lung metastasis Cancer that has spread to the lungs may trigger shortness of breath or a persistent cough. (5)
Can Cancer Cause Weight Gain?
While weight loss is a more common symptom of cancer, some people do experience weight gain.
The excess weight may be a side effect of medicines like steroids or hormones. Also, certain chemo drugs might cause you to retain extra fluids, which is known as edema. This can increase your body weight.
Or, you might simply eat more because you’re anxious or trying to improve nausea symptoms. A common side effect of steroids — given to prevent the nausea and allergic reactions that come with many chemotherapies — is increased appetite. Additionally, many people with cancer notice that their energy levels drop, which can lead to inactivity and weight gain. (7)
Can Cancer Affect Blood Pressure?
Some cancer medications, such as anti-VEGF drugs, can cause an increase in blood pressure. These treatments help block blood flow supply to tumors, but they also can affect other blood vessels in the body, which can elevate blood pressure. (8)
Also, high blood pressure may be a sign of certain cancers, such as adrenal cancer. (9)
Other treatments, such as chemotherapy and certain targeted drugs, may cause low blood pressure. (10)
Can Cancer Cause Blood Clots?
People with cancer have a greater risk of developing deep vein thrombosis (DVT; a blood clot that forms in a deep vein). Many cancers secrete substances into the blood that make the blood “thicker” and more likely to form a clot. Many chemo drugs may also up your risk for DVT. (11)
Why Does Cancer Cause Back Pain?
Most cases of back pain aren’t caused by cancer, but back pain can be an indicator.
Back pain is a symptom of many types of cancers, including primary bone cancer and those that have metastasized from the breast, colon, testicles, or lungs.
Usually, tumors put pressure on the spine and affect the nerves around it, which causes the pain. (12)
Why Noticing Cancer Symptoms Is Important
Identifying symptoms can help you and your doctor detect your cancer earlier. This is important because the sooner cancer is found, the better your prognosis. (13)
While symptoms are most likely caused by something other than cancer, you shouldn’t dismiss them. This is especially true if the problem has lasted a long time or has gotten worse.
RELATED: Lung Cancer Basics
Some Cancers Cause No Symptoms at All
Sometimes, people with cancer don’t experience any signs or symptoms at all. Others only have issues when the cancer has spread throughout their body.
For instance, ovarian cancer usually doesn’t cause any noticeable problems until it spreads to other organs. By the time this cancer causes signs or symptoms, it’s usually very advanced and difficult to cure.
It’s possible to spot cancers before you have any symptoms. Checkups and screening tests may be able to detect certain cancers in your body before they start affecting you.
Ask your doctor if you should have any special tests. If you have a family history of a certain cancer or have been exposed to specific risk factors, your physician may perform more aggressive testing.
When Should You Go to See Your Doctor to Be Checked Out?
It’s always a good idea to see your doctor if you have symptoms that concern you.
Your symptoms are most likely caused by something else, but it’s important to get checked out just in case. At the very least, your physician can help you figure out what’s causing the issues.
You’ll probably be referred to a specialist if your doctor thinks your symptoms are caused by cancer.
If you’re worried about developing cancer or have a family history of the disease but don’t have symptoms, it can still be helpful to talk to your doctor about your risk. Ask your healthcare provider about any screening tests or procedures that might be appropriate.