BOA/BHS Information to patients about newspaper reports on Cancer and Total Hip Replacements
We understand that people will be deeply worried by the stories that have appeared in the Sunday newspapers about total hip replacements and cancer. If you need specific advice about the type of hip replacement you have had or if you just want to speak and get advice then please see your general practitioner who may refer you back to your surgeon for a longer discussion.
We have put some information together for you about cancer and total hip replacement. Most patients do not have hip replacements with metal on metal bearings so that a metal ball rubs against a solid metal or metal lined socket (a metal on metal bearing): Only 1 in 6 (15%) of hip replacements recorded in the National Joint Registry are metal on metal.
Two studies were discussed at the British Hip Society in Manchester (March 1-2, 2012) one of which has been reported in the papers.
A study performed in Bristol has been reported on the 4th of March, 2012 in the Sunday Times and Telegraph.
The report on 71 patients with metal on metal surface hip replacements found abnormalities in cells lining the bladder in 15 patients which are not fully understood, but the suggestion is that these cell changes may, in very few patients and over long periods of time, lead to cancer. One patient in this study was found to have an early bladder cancer and we are not certain that this was caused by their hip replacement.
A second research project was presented from Newcastle that showed NO increase in the number of patients presenting with bladder cancers in 723 patients with metal on metal hip replacements compared to 2,016 with hip replacements where the ball is metal but the socket is plastic. These patients had been followed up for much longer than the previous study for between 6 and 14 years. This study was not mentioned in newspapers despite the fact that it did not show any link with cancer.
Neither of these studies have been scrutinised by experts to see if the information provided is sound and conclusions are correct. This is a process that all scientific papers go through before they are published in a scientific journal and before the observations made can be verified as true with certainty and any subsequent actions recommended.
What do we know about patients with hip replacements, cancer and survival?
- Many studies have shown that people with hip replacements tend to live longer than people who do not have hip replacements. This may be for many reasons. For instance, people who have surgery to increase their mobility may be fitter than the general population.
- Roughly 5% of people will have had a diagnosis of cancer before they have a hip replacement and roughly 8% will get cancer afterwards. Not because of the hip replacement but because cancer gets more common as we get older anyway. It is against this background that any potential increased risks are assessed.
- Population studies have shown that people tend to live longer after hip replacement and the rates of cancers are different. For instance, people with hip replacements have less lung cancer, less cancer of the stomach and colon but may have slightly more cancer of the bladder and melanoma of the skin. This is found in studies of tens of thousands of people, followed over very many years, some over twenty years.
- There are several factors that increase the risk for bladder cancer and the most important is probably cigarette smoking.
- A study in Finland by Visuri has looked at mortality after metal-on-metal (metal socket) and metal-on-polyethylene (plastic socket) Total Hip Replacements in Finland. They studied 2,164 patients over 16 years. Both bearing surfaces had lower overall mortality than the normal population.
- The National Joint Registry collects information on all patients having joint replacements and has done so since 2003. Provisional and early analysis, which is still ongoing, indicates that when compared with traditional hip replacement, the many thousands of patients with a metal-on-metal hip replacements did not have an increased risk of a cancer treatment in the seven years after surgery. This information has not yet been checked by independent experts.
The follow-up of patients with metal on metal hip replacements is still short and we cannot therefore say if there is an increased risk in the longer term of 10-30 years.
The British Orthopaedic Association and the British Hip Society, the National Joint Registry, the MHRA and Department of Health are all working together to understand more about this. Even as we write there is more research being done to make sure that we have the best possible evidence on which to base advice for our patients and surgeons.
Currently there is no verified evidence that having a metal on metal hip replacement increases cancer risk. It would be unwise to suggest removing these joint replacements and taking additional risks of surgery just on the possible risk of cancer.
More information will be available in the next few weeks and we suggest that we wait for the outcome of further investigations of larger studies.
If you are anxious please discuss this with your treating doctors.