Not all cancer patients lose a lot of weight. In fact, there are some cancers that result in weight gain during treatment. Certain types of chemotherapy, hormone therapy and medicines, such as steroids, can cause the body to retain fluids or increase a patient's appetite so that they eat more, causing weight gain.
This page was updated on May 3, 2022. The majority of cancer patients lose weight at some point in the course of the disease. Weight is sometimes the sign that leads someone to get diagnosed with cancer, but it may occur at any time, such as during treatment or in the advanced stages of the disease.
Weight loss can depend on cancer type
Weight loss can depend on the type of cancer you have. About 60 out of 100 people with lung cancer (60%) have a loss of appetite and significant weight loss at the time of their diagnosis. In people with upper gastrointestinal cancer, this number is 80 out of 100 people (80%).
Ovarian, lung, stomach and pancreatic cancers also commonly cause loss of appetite. Tumors release hormones that may distort your body's perception of hunger, making you feel full when you're not. The cancer may cause appetite-reducing symptoms such as nausea, pain, stress, depression and dehydration.
Weight loss is common among people with cancer. It may be the first visible sign of the disease. In fact, 40% of people say they had unexplained weight loss when they were first diagnosed with cancer.
Sometimes symptoms affect specific areas of the body, such as our tummy or skin. But signs can also be more general, and include weight loss, tiredness (fatigue) or unexplained pain. Some possible signs of cancer, like a lump, are better known than others.
How much weight loss is a concern. Your body weight can regularly fluctuate. But the persistent, unintentional loss of more than 5 per cent of your weight over 6 to 12 months is usually a cause for concern. Losing this much weight can be a sign of malnutrition.
Some causes of unintentional weight loss include: mental health conditions, such as depression, anxiety, eating disorders and obsessive compulsive disorder (OCD) problems with digestion, such as coeliac disease or irritable bowel syndrome (IBS)
Loss of appetite (anorexia)
It can happen in the early stages of cancer or much later if it grows and spreads to other parts of your body. As many as 50 in 100 people diagnosed with cancer (50%) have loss of appetite. For people with advanced cancer, up to 60 in 100 people (60%) lose their appetite to some extent.
It's because of this location, surrounded and obscured by internal organs, that pancreatic tumors are impossible to see or feel during a routine medical exam. Making diagnosis even more difficult is the fact that in its early stages, pancreatic cancer is usually a so-called “silent” disease and causes no symptoms.
A complete blood count (CBC) is a common medical test that your doctor may recommend to monitor your health. In cancer care, this blood test can be used to help diagnose a cancer or monitor how cancer or its treatment is affecting your body.
People who experience cancer fatigue often describe it as "paralyzing." Usually, it comes on suddenly and is not the result of activity or exertion. With this type of fatigue, no amount of rest or sleep helps. You feel physically, emotionally and mentally exhausted most of the time.
Extreme fatigue that doesn't get better with rest can be an early sign of cancer. Cancer uses your body's nutrients to grow and advance, so those nutrients are no longer replenishing your body. This “nutrient theft” can make you feel extremely tired.
Physicians should disclose a cancer diagnosis in a personal setting, discussing the diagnosis and treatment options for a substantial period of time whenever possible.
Some people in the advanced stages of cancer may feel or be sick a lot. This type of sickness is very different to that of people having chemotherapy or radiotherapy. It can severely affect your day to day life and make you very tired and depressed.
Tests on the tissue sample
Your team might do further tests on the sample of tissue (biopsy) used to diagnose your cancer. They might use immunohistochemistry (IHC) tests, which look for particular proteins on the surface of the cancer cells. These tests can sometimes tell which type of cell the cancer started in.
Sometimes, a cancer diagnosis comes out of the blue, with no symptoms at all. But more often, there are various symptoms that may be warning signs of the disease.
People diagnosed with pancreatic cancer might have recently lost a lot of weight for no apparent reason. This symptom is more common in cancers of the head of the pancreas.
The dying person will feel weak and sleep a lot. When death is very near, you might notice some physical changes such as changes in breathing, loss of bladder and bowel control and unconsciousness. It can be emotionally very difficult to watch someone go through these physical changes.