Losing weight when you are not trying to is a very common symptom in people with cancer. It may be one of the reasons you first go to the doctor.
Weight loss and cancer
There are many causes of weight loss, many of which can be treated.
Losing weight is often associated with loss of appetite. But this is not the only cause. You may be eating normally but still losing weight. Your body may not be absorbing all the fat, protein and carbohydrate from the food you eat. Or your body may be burning up calories faster than normal.
Continuous weight loss can be worrying and a constant reminder of your illness. It can affect how you feel about yourself.
Weight loss can depend on cancer type
Weight loss can depend on cancer type.
About 6 out of 10 people (60%) with lung cancer have lost a significant amount of weight by the time of their diagnosis. In people with stomach cancer, pancreatic cancer or oesophageal cancer this number is 8 out of 10 people (80%).
People with breast cancer or prostate cancer don't tend to have lost weight at diagnosis.
When to worry about your weight
If you are not dieting and you lose more than 5% of your normal weight in 1 month or 10% in 6 months, your doctor will want to find out the cause.
For example, if you normally weigh 10 stone (63.5 kg) and lose half a stone (3kg) in a month, or a stone (6kg) in 6 months that would need investigating.
This may not seem like a lot of weight, but if you continue to lose weight at this rate, it could become a serious problem.