Is Weight Loss a Symptom of Ovarian Cancer or Other Cancers?

Doctor weighing female patient on scale
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When is weight loss that is unintentional and unexplained a sign of ovarian cancer?

Unexplained Weight Loss

The term unexplained weight loss is used to define weight loss that is unintentional. By definition, this refers to a weight loss of five percent or your body weight over a period of six to 12 months.  For example, if a woman who ordinarily weighs 150 pounds loses seven pounds or more in less than a year without trying—without changing her diet or exercise program—this would be referred to as unexplained weight loss.

Unintentional weight loss certainly warrants a trip to the doctor. There are many causes of unexplained weight loss. It's still unlikely that you are living with an undiagnosed cancer, but a thorough work-up would be recommended.

Again, the unintentional part of this equation has to be stressed. This weight loss is often described as happening fairly suddenly and without any dieting or effort. Many women with ovarian cancer report weight loss as a symptom, and it may be the first symptom of the disease.

It usually happens suddenly without dieting or effort. A study looking at all types of cancer found that 40 percent of people had lost weight at the time of their initial diagnosis. By the time a cancer progresses to the advanced stages, that number is much higher—around 80 percent.

Nearly any cancer can cause unexplained weight loss, but the more common types include ovarian cancer, cancer of the pancreas, esophageal cancer, and lung cancer.

Unintentional weight loss is more likely to be related to cancer if you have any of the common symptoms of cancer, such as a chronic cough, shortness of breath, a lump, changes in your stools, or a sore which doesn't heal.

Weight Loss: A Cancer Symptom

Researchers have wondered how often the symptom of unexplained weight loss is due to cancer.

One study carefully evaluated this question. It was found that 38 percent of people without any symptoms, and who went to their doctor because of unintentional weight loss, had an underlying cancer.

Certainly having some symptoms may increase these chances. For example, if someone also has symptoms of ovarian cancer, such as abdominal bloating, changes in bowel habits, and pain during intercourse, the chance that ovarian cancer is the underlying cause of the weight loss is considerably higher. Of the 38 percent, cancers of the abdominal and pelvic regions, such as ovarian cancer, were responsible for 50 percent of these cancers.

Lab Abnormalities

Researchers have looked carefully at how tests done in the lab may give a clue to an underlying cancer.  Several lab tests were studied in a few different clinical trials. It's been found that looking at labs to determine if weight loss is due to cancer has some inconsistencies.

Yet overall it's been found that having at least one abnormal level raises the risk that weight loss is due to cancer.  Labs that were evaluated in this setting included alkaline phosphatase (ALK,) lactate dehydrogenase (LDH,) blood counts (looking in particular for a high white blood cell count,) sed rate, c-reactive protein.


There are many mechanisms by which people may lose weight with cancer. Some of these include:

  • A general lack of appetite with cancer
  • Mouth sores or taste changes from chemotherapy
  • Metabolic activity requiring increased nutrients
  • Fatigue, which makes the thought of preparing a meal overwhelming
  • Depression and grief reactions—some people stop eating when they are depressed, and cancer results in an increased risk of depression.

A Word From Verywell

If you've experienced unintentional weight loss, talk to your doctor. There is a chance it could be cancer and specifically ovarian cancer. Yet it could also be due to other serious medical conditions.


American Cancer Society. Signs and Symptoms of Cancer. 08/11/14.

American Society of Clinical Oncology. Cancer.Net Weight Loss. 11/2014. 

Baicus, C., Rimbas, M., Baicus, A. et al. Cancer and involuntary weight loss: failure to validate a prediction score. PLos One. 2014. 9(4):e95286.

Hernandez, J., Riancho, J., Matorras, P., and J. Gonzalez-Macias. Clinical evaluation for cancer in patients with involuntary weight loss without specific symptoms. American Journal of Medicine. 114(8):631-7.