Radioactive Bacteria Attack Cancer

ananyo writes "Two dangerous things together might make a medicine for one of the hardest cancers to treat. In a mouse model of pancreatic cancer, researchers have shown that bacteria can deliver deadly radiation to tumours — exploiting the immune suppression that normally makes the disease so intractable. The researchers coated the bacterium Listeria monocytogenes with radioactive antibodies and injected the bacterium into mice with pancreatic cancer that had spread to multiple sites. After several doses, the mice that had received the radioactive bacteria had 90% fewer metastases compared with mice that had received saline or radiation alone."

Comments

So how do I pass these radioactive bacteria?

[ackthpt]

Magically transport them to a parallel universe or pass them through me kidneys?

I've already been nuked, lymphnodes on my lower left side, so I'm a little aware of side effects and long term prospects (so far so good, touch wood) maybe if we could train bacteria which do not require bringing in radiation we'd really be on to something.

Still, it's progress.

Re:So how do I pass these radioactive bacteria?

[MatthiasF]

I assume since they are covered in radioactive anti-bodies, that they cannot reproduce and would die eventually from the radiation exposure.

And I highly doubt they would inject more than a safe limit into you if they did use these for treatment based on your level of kidney function.

Probably ending up using a whole lot less radiation then the levels that nuked you.

Re:So how do I pass these radioactive bacteria?

[plover]

Even if the bacteria continue to reproduce in harmful rates, they can be treated later with antibiotics. First things first - target the cancer cells. Then you can worry about what the infection might have done to you.

Re:So how do I pass these radioactive bacteria?

[quantaman]

From what I understand the bacteria themselves aren't attacking the cancer.

The bacteria are being covered with radiation, most of the bacteria are quickly killed by the immune system and expelled from the body. But since the tumour suppresses immune activity the bacteria in the tumour last quite a bit longer and keep irradiating the tumour. So basically the bacteria are being used to deliver the radiation directly to the tumour.

So it sounds like there's no real way of getting around the radiation or radiating your kidneys to some extent. But if you have pancreatic cancer long term prospects probably aren't your primary concern :(

The other issue is that the other researchers in the article sounded a bit skeptical. It could be this is another example of a medical breakthrough in the headlines that doesn't pan out.

Re:So how do I pass these radioactive bacteria?

[ShanghaiBill]

Magically transport them to a parallel universe or pass them through me kidneys?

Many medical isotopes have a half-life of just a few days. So by the time the bacteria are done doing their job, the radioactive isotopes have decayed to a harmless level. Since the half-lives are so short, these isotopes cannot be stockpiled, and need to be generated in a reactor no more than a day or so before they are used. There are only a few reactors in the world configured to make these isotopes. The Chalk River Reactor in Ontario makes most medical isotopes for North America, and there was a major shortage of these isotopes in 2007 when it had to shut for maintenance.

Re:So how do I pass these radioactive bacteria?

[Anonymous Coward]

Half life of the isotope used in this experiment, Rhenium-188, is just under 17 hours.
http://www.ncbi.nlm.nih.gov/pubmed/9169563

Re:So how do I pass these radioactive bacteria?

[fragMasterFlash]

With the ability to target cells, specifically immunodeficient cancer cells, the total dosage of radioactive material needed should be greatly reduced. This would seem to be favorable to techniques that target all tissues in the vicinity of a tumor.

Re: So how do I pass these radioactive bacteria?

[viperidaenz]

In the US, Listeria kills 500 people a year. Pancreatic cancer kills 37000. I'd rather have the food poisoning thanks.

Re:One small problem

[Guido von Guido II]

All we have to do to treat you... ..is dose you with toxic, radioactive bacteria!

Compare it to chemo and radiation therapy. If they can deliver the bacteria safely (which is a big if) and if it ends up delivering less radioactivity to the patient than ordinary radiation therapy, it might end up being safer. Treating cancer is often about trade-offs.

Cue the spiderman theme!

[bferrell]

Spiderman, spiderman... Does whatever a spider can... :)

Re:Conclusion:

[fuzzyfuzzyfungus]

Please, do expound as to why your stated fact is important here.

Well, it does mean that they aren't 'cured', and probably places a somewhat uncomfortable upper-probable-bound on how long it will take for the tumors to rally and start expanding again. That's a less than optimal outcome.

On the plus side, there can be a real difference between "Yup, totally fucked, maybe 6 weeks?" and "Yup, totally fucked, 18-20 months, most likely."(especially if the treatment can be made not-terribly-debilitating)

Mutation danger?

[gmuslera]

If well those bacterias are targetting in a way or another tumours, their radiation they carry could cause on them random changes on the ADN that could lead to more dangerous diseases?

Re:Mutation danger?

[Ambassador Kosh]

You could actually do the math for the mutation rate and the odds of a mutation being useful and weigh that against the odds of survival by the patient without the treatment. The math is probably not too bad and it is something that the scientists involved probably considered. Sure there is a non-zero chance of it happening but without this the odds of surviving pancreatic cancer is close to zero. I had a friend die from that one and it is definitely not the way you want to go. It is a very soft organ and VERY hard to treat with surgery, chemo or other drugs. It is one of the hardest to treat cancers we know of. So this kind of treatment is better than what we have even if it could mutate into something and kill you.

Re:Conclusion:

[silentcoder]

At the rate we're discovering real and viable cures - 18-20 months is indeed worth it as there is a good chance of that being long enough to be around when a complete recovery becomes possible.
It's happened in my own life. About a year ago very good friend of mine started complaining about severe pain in her side, physio didn't help but the physio noticed something off and suggested she go for a scan. The scan revealed metathesized lymphatic melanoma - the biggest tumour was almost 15cm long, wrapped around her kidney arteries at that.
Initial prognosis: inoperable, incurable - 10 months to live, 18 if she's really lucky.

A surgeon however decided to operate, he knew he couldn't remove the tumor but as he said "I'll cut out as much as I can - and buy you time". He did just that - which turned out be only about 3cm that could be safely cut out, but it bought her a few more months.
4 Months later her oncologist called her to let her know about a drug trial for a new treatment (sorry, I don't know the name) which is a form of chemo based on gene-therapy, it specifically and exclusively targets cells with the specific mutation of the cancer she has, so they can use much higher doses than is usually safe with chemo (because it has almost no side-effects and doesn't affect other cells). He got her into the trial group.

Three weeks ago she announced that all the spread tumors were gone, and the main (original) tumor was down to about 2cm in size. It's likely that when the trial ends she'll still need surgery to get rid of the last bit -but her prognosis now is full recovery and cancer free before the end of this year.

That is why it's worth keeping them alive as long as possible - every DAY we buy them, massively increases their odds of a full recovery.