Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: OldMan on 01/07/2004 04:18:29
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How much of the hip is actually replaced when they do a hip replacement and could you do the same sort of thing with a sternum?
If someone had a tumour in their sternum is there anyway to operate on it safely without the risk of dropping cancerous cells all over the place? Could you say remove the entire sternum and replace it with say a hardened plastic or metal one perhaps?
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A prism with an intellect, you throw your light selectively.
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Anyone know? Been up here a few days and no replies yet.
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A prism with an intellect, you throw your light selectively.
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THR - total hip replacement is precisely that. You cut the top off the femur - the long 'thigh' bone, shove a big metal insert with a ball on the top down the middle of the bone, glue it in place with some bone cement (like superglue), do the equivalent with the socket (i.e. replace it with a plastic one) and then connect the two together. Hey presto, a new hip.
A sternum is an unusual request ! Most hips are replaced because age-related disease (osteoarthrosis / osteoarthritis) has produced a painful joint capable of only limited degrees of movement.
It is possible to remove bones without spreading cancerous cells (that depends upon the skill of the surgeon), but I would be concerned about where the cancer came from in the first place because primary bone tumours are not that common. Most cancers in bone are actually secondaries (metastases) from breast, lung, kidney, thyroid or prostate primaries.
However, bone removal may not be necessary. Sometimes the problem can be controlled with radiotherapy and chemotherapy. Please tell us a bit more about the medical scenario to which you are referring.
Chris
"I never forget a face, but in your case I'll make an exception"
- Groucho Marx
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You may have already joined the dots but tis related to the kidney cancer topic I posted. I thought it would be a pretty unusal request about removing a sternum but it was a thought that crept into my head at some stage.
Down to the scenario. Last year my dad found out he had renal cancer because his sternum had fractured due to a secondary tumour that had grown there. They whipped out the kidney concerned, gave him radiotherapy on his sternum and said good luck. They contemplated immunotherapy but decided against it due to the harshness of the treatment and the lack of evidence that it is succesful. Now I've known pretty much since we found out about it that the long term chances aren't all that fantastic due to the difficulty of treating kidney cancer, particularly metastases.
Well last week we found out that there is another metastases in his left hip and he'll be having 10 days of radio on that from the front and back. Judging from the past though that may very well not work. While they were scanning his hip they did the rest of his body and found the tumour in his sternum hadn't gotten any smaller but had actually grown. Perhaps the radio had slowed it down, I don't know. I can't remember how big that one is but it was big enough to fracture the sternum at some stage so a reasonable size I would guess.
That is where it is at for the moment. So what say you Doc? It doesn't look all that great, I think the radiologist also encouraged him to ask his oncologist if he was doing any trials of new treatments as well.
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Firstly, I'm sorry to hear about your Dad, it's a very unfortunate scenario.
When you administer radiotherapy you are relying upon the fact that cancer cells divide very rapidly and are therefore rapidly turning over their DNA, making it more susceptible than healthy tissue to damage by the radiation.
But tumours are a heterogeneous mix of cells, all dividing at different rates and different times, and some cells are more abnormal than others.
This means that the radiotherapy can often miss some cells which can then subsequently 'seed' recurrent tumours at the same site, or elsewhere.
So why not administer more radiotherapy then, to take them all out ? Well, unfortunately, whilst cancer cells are more sensitive than healthy tissue to the effects of radiation, eventually healthy tissue is damaged too, particularly the lungs - which can develop fibrosis - and the heart. So it's all about treading a fine line between hurting the tumour as much as you can, and hurting the patient as little as possible.
The evidence is that radiotherapy is very good for pain relief and control of local symptoms produced by metastatic disease. There are some conditions in which it can also be curative, but, in the context of disseminated cancer, its main application is in zapping troublesome mets.
Surgery is often not the best option because, with metastatic disease, it is associated with considerable morbidity (and mortality) for the patient, yet has no impact on survival.
I wish I could offer you a more positive response, but I regret that there are no magic cures for this condition. The emphasis must therefore be placed on achieving the best quality of life possible, and ensuring that your dad remains comfortable and pain free. Luckily we're pretty good at that these days, and there are some excellent support services on offer which can make a huge difference.
Best wishes,
Chris
"I never forget a face, but in your case I'll make an exception"
- Groucho Marx
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Thanks for all that Chris much appreciated and once again you've help expand some of my not so vast knowledge. I've made my peace with the situation and know that it is more about the quality not quantity from here on.
Cheers
Tim
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A prism with an intellect, you throw your light selectively.