Unexplained Weight Loss and Cancer: When To Worry

By Dr. Sajjan Rajpurohit in Cancer Care / Oncology

Jan 23 , 2023 | 2 min read


Unexplained weight loss, or losing weight without attempting, can be a symptom of different conditions. While it isn't always a cause for concern, it's essential to know when unexplained weight loss can indicate something more serious - like cancer.

In this blog, we will discuss unexplained weight loss and when you should start worrying. We'll look at the causes and signs of cancer-related weight loss and what you can do if you suspect that cancer may be the underlying cause.

Causes of unexplained weight loss

There are many potential causes of unexplained weight loss, and cancer is one possible cause. However, it is important to remember there are many other potential causes of weight loss, and not all of them are serious.

Some common non-serious causes of weight loss include stress, changes in diet or exercise habits, and normal fluctuations in body weight. However, if you lose weight without trying and don't know why, it's important to see a doctor.

Cancer is a possible cause of unexplained weight loss, but there are many other potential causes. If you are concerned about your weight loss, speak to your doctor.

Cancer and weight loss

Cancer and weight loss are often linked. Unexplained weight loss, especially when accompanied by other cancer symptoms, can be a sign of cancer.

There are many causes of unexplained weight loss, so it's important to see your doctor if you're losing weight without trying. Cancer is one potential cause of unexplained weight loss. Other potential causes include thyroid problemsdiabetes, and depression.

If you're experiencing unexplained weight loss, inform your doctor about all your symptoms. Your doctor will likely order some tests to rule out other potential causes of your symptoms. If cancer is suspected, additional testing will be needed to confirm the diagnosis.

When to see a doctor

If you are experiencing unexplained weight loss and think you may have cancer,  see a doctor as soon as possible. Cancer can cause weight loss in several ways:

  1. Cancer cells can use up a lot of the body's energy, leading to weight loss.

  2. Cancer can cause changes in appetite, leading to weight loss.

  3. Cancer can lead to nausea and vomiting, which can also cause weight loss.

  4. Cancer can cause diarrhoea, leading to weight loss.

  5. Certain types of cancer (such as leukaemia) can cause a build-up of fluid in the abdomen, leading to weight loss.

Treatments for cancer-related weight loss

There are many possible treatments for cancer-related weight loss, depending on the underlying cause. If the weight loss is due to a decrease in appetite, medications that stimulate the appetite may be prescribed. If the weight loss is due to an increase in metabolism, medications that slow down the metabolism may be prescribed. If the weight loss is due to malabsorption, supplements and/or special diets may be recommended. And if the weight loss is due to emotional stress, counselling and/or support groups may be helpful.


Unexplained weight loss can be a serious symptom to consider when it comes to cancer, but there are many other causes of unexplained weight loss that may be more likely. However, if you have experienced sudden and significant weight loss along with other symptoms such as fatigue, pain or night sweats it is important to see your doctor right away. Your doctor will help you determine the cause and provide appropriate treatment so you can feel better soon.