Hypertrophic pulmonary osteoarthropathy (HPOA)

My mother has advanced lung cancer and been told she has hypertrophic pulmonary osteoarthropathy. I can't find any simple information on this. Could you please explain what it means?

This is a long and complicated name for a collection of symptoms, or a syndrome, in this case affecting the lungs. Looking at the meaning of each word on its own can help to understand what this syndrome is.

• Hypertrophic means an enlargement or overgrowth of a body organ
• Pulmonary relates to the lungs
• Osteoarthropathy is a disease of the bones and joints

You may also hear the term hypertrophic osteoarthropathy (HOA) as this syndrome isn't always linked to lung disease. HOA can just occur on its own, when it is called primary hypertrophic osteoarthropathy. Or it can be related to a lot of other diseases, including sometimes cancer.

HPOA is a rare syndrome, so there is very little information about it. Most information is about individual case studies reported in medical journals and text books, which can be difficult to understand. Hypertrophic osteoarthropathy means an increase in the growth of skin and bone. This usually happens because of an inflammation somewhere in the body. Pulmonary is in there because the syndrome can happen in people with lung disease. It affects about 5 out of every 100 people (5%) with cancer of the windpipe (bronchus) or lung, and up to 50% of patients with pleural mesothelioma. In cancer, it is most common in people with non small cell lung cancer. We don't really know why it happens to some people with lung cancer and not others.

HPOA is a group of symptoms.  In cancer, it can be caused by substances released by a tumour. Or by substances the body makes because it is reacting to the tumour. 

HPOA most often affects the bones and joints of the wrists and ankles. Sometimes this shows up as changes on bone scans or X-rays. One of the most common symptoms of HPOA is a condition known as clubbing. This means the fingers and toes broaden at the ends, and the nails curve and thicken. Clubbing of the fingers is a common symptom associated with lung and heart conditions. No one knows exactly why clubbing develops but it may be a result of too little oxygen in the blood. 

HPOA can affect muscles and joints like arthritis. The ankles and wrists may become swollen and inflamed, causing a lot of pain and difficulty with movement. Treatment is usually with painkilling drugs such as non steroidal anti inflammatory drugs. 

There have been some reports that drugs called bisphosphonates can help to relieve pain in people with HPOA. Bisphosphonates help to slow down the destruction of bone. But there is not enough evidence to know how well these drugs work in helping to treat symptoms of HPOA. 

Advanced cancer causes many symptoms that many people find very hard to cope with. Your mother’s doctors and nurses will be aware that she has this syndrome. They will be doing all they can to make sure she is as comfortable as possible. It may help to speak with her doctor to find out more about her condition. You may also find it useful to look at the information about advanced lung cancer in the treatment for advanced lung cancer section of CancerHelp UK.