Can dogs smell cancer?

[NeilC]

Anyone (UK) see the TV programme last night of the same title?

Looked interesting.

A couple of things struck me. The reaction of some in the scientific community seemed to me to bordering on cynicism rather than skeptcism. Seems to me some of them had a bit of a closed mind about something which, on the face of it, could easily work.

One guy from the cancer charity was sniggering at it and saying that although the dog had detected cancer that it wasn't reliable enough and people would want to be sniffed by a dog. Didn't occur to him that if dogs can sniff cancer then we could develop better training protocols and breed dogs for it and improve the hit rate enormously. If my dog asked me to breath on his dog on the basis that it might detect lung cancer I'd be all for it.

 

[Rolfe]

We've been through this before, when the original paper came out. What the paper said was that it seemed to be possible to train dogs to distinguish urine samples from patients with a certain type of urinary tract cancer from normal specimens. Which suggested there was a specific molecule there that they were detecting. Which suggested that if the molecule could be isolated and identified, a good assay for it might be helpful in diagnosing that type of cancer.

Perfectly sensible, shorn of the media spin.

Rolfe.

 

[Kiless]

Are you talking about the documentary by Jemima Harrison?

I thought of this topic and remembered Richard Adam's The Plague Dogs. I typed in the Plague Dogs and cancer - and found finding this, from Times online (a two page article, this is quoted from the second page - http://www.timesonline.co.uk/article/0,,2092-1859073_2,00.html - I'd also suggest page one, of course.)


Firmly against “doctor dogs” is Dr Richard Sullivan, director of programmes and centres at Cancer Research UK, which spends £230m a year on cancer studies. “Can you use dogs to detect cancer? No, you can’t. Be serious. Dogs carry disease,” he said.

“Then there’s the huge quality control and health and safety problems. It would be interesting to know whether patients would trust a cocker spaniel over a diagnosis of whether or not they had lung cancer.”

“What dogs may do, though, is provide a proof of concept. There may be some mileage in developing electronic breath tests. Machines don’t get tired. The dog has that fantastic kind of fuzzy intelligence, but being a biological device is also its big negative. But the main point is that this is a small sample and we believe the more people come into the sample, the more unreliable the dogs will be.”

Dr Wallace Sampson, a retired oncologist and editor of the Scientific Review of Alternative Medicine, a “debunking” journal that lists magicians among its supporters, is also unimpressed. “Cancers of different tissues do not share similarities,” he said.

“There would have to be a chemical substance that dogs are capable of smelling and that’s unlikely. The kind of results these people are getting are way out of the probability range.

“I can’t dismiss it out of hand but I’m sceptical. I don’t object to dogs sniffing. I think that’s a remarkable talent they have. The question is: how consistent could it be to be useful as a test? They’re going to have to go pretty far to prove that.”

It goes on to state that dogs sense of smell may be better than we thought and -

...The cancer-sniffing dogs so far remain firmly part of “alternative” medicine and, as such, open to scepticism. But Jemima Harrison, writer and director of tonight’s documentary, says we should be open-minded: “Science knows some of the answers but it doesn’t know everything. Having come late to science I’m a bit of a born-again reductionist. But the more you know about science, the more you realise it’s work in progress.”

 

[NeilC]

Not sure if it was by Jemima Harrison. It was on BBC 4 and called "Can dogs smell cancer?". Certainly sounds quite similar.

The results shown on the programme were much more impressive than that one paper on bladder cancer.

 

[Kiless]

Not sure if it was by Jemima Harrison. It was on BBC 4 and called "Can dogs smell cancer?". Certainly sounds quite similar.

The results shown on the programme were much more impressive than that one paper on bladder cancer.

Yeah, I bet.

I teach documentaries to students. We do two weeks on Bowling For Columbine.

Then I show them Michael Moore Hates America.

You should see the difference in the essays they write from one to the other. It's why for the final tertiary entrance paper, the questions on the non-print section generally don't discriminate between feature film and documentary. Often they suggest to students to discuss at length manipulation and positioning of the audience to promote a certain view in EITHER film or documentary. Fascinating stuff.

And if you go down to your local video store, have you noticed how documentaries, which used to be filed up the back with the David Attenborough nature series and the 'Shocking Asia!' exploitation videos, are now neatly put next to the latest releases? In fact they ARE the latest releases? No longer charging weekly rates for 1989's 'Roger and Me'...

It's a boon for teachers. Means I don't have to teach 1988 doco 'Cane Toads' or three-year old Four Corners (short documentary series on Australian television) eps. I've brought about a dozen crisp, clear DVD documentaries already this year. Lovely quality. Some are Academy award winners or BAFTA nominees. Even got notes and texts from educational journals and film mags for most of them. That sure didn't happen back in the 90s....

For the public? The word 'documentary' overlooks the fact that a nice glossy cover and half a dozen copies on the shelves indicates that there's a market out there. Always has been...

And if you want to sell copies and raise ratings... gotta make it glossy.

 

[Corpse Cruncher]

Animals have a keen sense of smell and I guess here, more than beyond the human range of smell detection. Could it be that a person with cancer gives off a smell that an animal might detect?

 

[NeilC]

Yeah, I bet.


For the public? The word 'documentary' overlooks the fact that a nice glossy cover and half a dozen copies on the shelves indicates that there's a market out there. Always has been...

And if you want to sell copies and raise ratings... gotta make it glossy.

Obviously the documentary is meant to entertain as well as inform.

What was apparent was that the bladder cancer study might not be representative of what is possible. That was one study, one type of cancer and one dog (as far as I know). People altering these parameters APPARANTLY are getting much more impressive results - TV spin aside.

 

[Rolfe]

Animals have a keen sense of smell and I guess here, more than beyond the human range of smell detection. Could it be that a person with cancer gives off a smell that an animal might detect?

There's no such thing as a homogeneous disease called "cancer", and it's more likely that there are different markers for the different types of cancer. But it's perfectly possible that there may be marker compounds present that the dogs can detect. For my money, the utility of that would be in knowing that there must be such a compound if the dogs appear to be able to detect something, then identifying it and developing an in vitro assay.

Rolfe.

 

[Kiless]

Obviously the documentary is meant to entertain as well as inform.

What was apparent was that the bladder cancer study might not be representative of what is possible. That was one study, one type of cancer and one dog (as far as I know). People altering these parameters APPARANTLY are getting much more impressive results - TV spin aside.

Did my link (in particular, the first page) reflect any of the research done? Who were the people altering the parameters?

 

[Capsid]

Prostate cancer is partly diagnosed by an increase in the blood of prostate specific antigen. Most cancers are fast growing cells that will secrete proteins specific for the cell type, so the whole concept is not without precedent.

 

[NeilC]

Did my link (in particular, the first page) reflect any of the research done? Who were the people altering the parameters?

Yes I think your link is a fair sumnation of the programme I saw. Ie the pine street people were the ones who were getting very good results.

 

[Jyera]

We've been through this before, when the original paper came out. What the paper said was that it seemed to be possible to train dogs to distinguish urine samples from patients with a certain type of urinary tract cancer from normal specimens. Which suggested there was a specific molecule there that they were detecting. Which suggested that if the molecule could be isolated and identified, a good assay for it might be helpful in diagnosing that type of cancer.

Perfectly sensible, shorn of the media spin.

Rolfe.

Agree.

 

[Jyera]

There's no such thing as a homogeneous disease called "cancer", and it's more likely that there are different markers for the different types of cancer. But it's perfectly possible that there may be marker compounds present that the dogs can detect. For my money, the utility of that would be in knowing that there must be such a compound if the dogs appear to be able to detect something, then identifying it and developing an in vitro assay.

Rolfe.

Agree.

I recall a book called "Biomimicry" where we are encouraged to learn from our fellow earthings. The dogs have evolved nose that can detect more things than human nose. If that nose prove useful for detecting certain disease, it make sense to explore the science of it..

To have a dog bred for detecting certain illness might prove useful to prevent bio-terrorism, where a sick suicide carrier carries deadly disease into a country.

 

[Ducky]

Multiple Myeloma has a marked increase in monoclonal proteins from tumors in the blood and a high urine calcifacation. If a dog can smell that, then yeah.

Other wise, you'd have to figure out what about each individual cancer might give off a smell.

I'm with Rolfe (posst #8) on this one.


ETA:

By the way, the two tests I do often is blood and urine for just those two features. If a dog can smell them, what's the point?

 

[Rolfe]

By the way, the two tests I do often is blood and urine for just those two features. If a dog can smell them, what's the point?

None, if you already know what the dog is detecting. But if a dog seems to be able to reliably detect something which doesn't have a known marker substance, it implies that there is indeed such a substance present, and that if this can be identified and an in vitro assay developed, then it could be a useful test.

But in fact there are many many different monoclonal proteins in different myeloma cases, so it's doubtful that a dog could in fact smell generic "myeloma".

Rolfe.

 

[jemimaharrison]

The documentary by Jemima Harrison? Ah yes, that would be the one.

So if any of you want to ask any direct questions - or debate the demands of entertainment over scientific accuracy, please go ahead..

Jemima

 

[The Don]

The documentary by Jemima Harrison? Ah yes, that would be the one.

So if any of you want to ask any direct questions - or debate the demands of entertainment over scientific accuracy, please go ahead..

Jemima

Okay. Because I don't have a link to the original study, I'd be interested to know:

- How many studies have been carried out into dogs detecting cancers
- What were the study sizes
- What kind of blinding was included in the studies
- Were the studies concentrating on specific cancers or all cancers
- What were the detection rates in the studies
- What were the false positive rates in the studies

 

[The Don]

Bump...

To give JemimaHarrison a chance

 

[jemimaharrison]

Okay. Because I don't have a link to the original study, I'd be interested to know:

- How many studies have been carried out into dogs detecting cancers
- What were the study sizes
- What kind of blinding was included in the studies
- Were the studies concentrating on specific cancers or all cancers
- What were the detection rates in the studies
- What were the false positive rates in the studies

• Three studies: Amersham UK (published in the BMJ Sept 2004 - online via bmj.com); Cambridge Vet School (unpublished) and Pine St, USA (to be published Spring 2006 in Integrative Cancer Therapies).

• Sizes varied: Amersham as above (six trained dogs. 36 cancer patients, 108 controls); Pine St - 86 cancer patients, five dogs, 83 controls; Cambridge - see below.

• Blinding an interesting issue. Amersham: fully blinded. Pine St: the dogs and their handlers were blind and there was no one in the room who knew which sample was there but there was an observer hidden behind a curtain who could give a "yes" or "no" (via a clicker) when the dog made their choice.

This was done to give the dog feedback (all the groups discovered that dogs could retrain on to a different stimulus if they were wrongly rewarded or not rewarded - an issue now being tackled, successfully, by Amersham). The curtain method obviously leaves open the possibility of unintentional auditory cues (I don't think there were, but it needs to be addressed in future work).

• Which cancers? Amersham - bladder. Cambridge - prostate (and therein lay their problem, I think - almost impossible to be confident of healthy controls). Pine St: lung and breast (different dogs for each).

• Detection rates: Amersham - 3 x chance (and now up to 90 per cent in subsequent fully-blinded training). Cambridge - inconclusive (for lots of reasons happy to expand on if people interested); Pine St - about 90 per cent success (and between 1 and 5 per cent false positives depending on criterea).There are all sorts of qualifying factors in all three studies, but the conclusion we make in the film - which I really believe to be a fair one - is that, although loads more work needs to be done, there's a good chance dogs can detect a marker associated with cancer and it would be a real shame if the research died from lack of proper funding (which it is in danger of doing).

We have another, very tricky, science film in production at the moment (for BBC2). It's really tough to tell a big science story in an hour (because of course you have to start off from the premise that your audience knows nothing). As such, you have to cherrypick what you do and do not include. The most that you can aim for (as, indeed, is the case in any authored material) is to tell the truth as you see it - and that that view has been formed by rigorous research.

Jemima

 

[The Don]

Thank you for your response

Which means that this is officially interesting but far from conclusive. Clearly when the two other studies are published (and peer reviewed) then there will be more of a body of work rather than a single trial.

I agree that any study which is insufficiently well blinded is really for information only. It looks like Pine St. were training the dogs at the same time they were conducting the study. I'd be interested to learn why they dodn't train the dogs first and then run the study blinded. It'd have helped credibility.

The BMJ Abstract is here:

http://bmj.bmjjournals.com/cgi/content/abstract/329/7468/712