Radioactive implant wipes tumors in unprecedented pre-clinical success

Radioactive implant wipes tumors in unprecedented pre-clinical success
Scientists have demonstrated the potential of a new tool against difficult-to-treat pancreatic cancer
Scientists have demonstrated the potential of a new tool against difficult-to-treat pancreatic cancer
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Scientists have demonstrated the potential of a new tool against difficult-to-treat pancreatic cancer
Scientists have demonstrated the potential of a new tool against difficult-to-treat pancreatic cancer

Engineers at Duke University have developed a novel delivery system for cancer treatment and demonstrated its potential against one of the disease’s most troublesome forms. In newly published research in mice with pancreatic cancer, the scientists showed how a radioactive implant could completely eliminate tumors in the majority of the rodents, demonstrating what they say is the most effective treatment ever studied in these pre-clinical models.

Pancreatic cancer is notoriously difficult to diagnose and treat, with tumor cells of this type highly evasive and loaded with mutations that make them resistant to many drugs. It accounts for just 3.2 percent of all cancers, yet is the third leading cause of cancer-related death. One way of tackling it is by deploying chemotherapy to hold the tumor cells in a state that makes them vulnerable to radiation, and then hitting the tumor with a targeted radiation beam.

But doing so in a way that attacks the tumor but doesn’t expose the patient to heavy doses of radiation is a fine line to tread, and raises the risk of severe side effects. Another method scientists are exploring is the use of implants that can be placed directly inside the tumor to attack it with radioactive materials from within. They have made some inroads using titanium shells to encase the radioactive samples, but these can cause damage to the surrounding tissue.

"There's just no good way to treat pancreatic cancer right now," said study author Jeff Schaal.

Schaal and his team explored an alternative type of implant, one made from more biocompatible materials that wouldn’t post the same risks to the human body. The scientists used synthetic chains of amino acids known as elastin-like polypeptides (ELPs), which remain in a liquid state at room temperature but form a stable gel-like material in the warmer environment of the body.

This substance was injected into tumors in various mouse models of pancreatic cancer along with a radioactive element called iodine-131, an isotope that is well-studied and widely used in medical treatment. In this environment, the ELP entombs the iodine-131 and prevents it leaking into the body, but allows it to emit beta radiation that penetrates into the surrounding tumor. Once the radiation is spent, the ELP biogel safely degrades into harmless amino acids.

The treatment was tested in combination with a common chemotherapy drug called paclitaxel. The radioactive implants were injected into cancer tumors just beneath the skin, but with mutations known to occur in pancreatic cancer, and into tumors within the pancreas itself that are historically more difficult to treat.

Across all the models tested, the scientists report a 100% response rate to the treatment. In three quarters of the models, the dual treatment completely eliminated the tumors 80% of the time. The scientists deployed the novel treatment against pancreatic cancer because they wanted to explore its potential against one of the trickiest forms of the disease, but believe these results bode well for its wider application.

"We think the constant radiation allows the drugs to interact with its effects more strongly than external beam therapy allows," Schaal said. "That makes us think that this approach might actually work better than external beam therapy for many other cancers, too."

There is lots to play out before that happens, with trials on larger animals the immediate next step for the researchers. They do say these findings are unparalleled in terms of how effectively the treatment was able to disintegrate the tumors, with team member Ashutosh Chilkoti describing them as “perhaps the most exciting” results against late-stage pancreatic cancer his lab has produced in almost 20 years.

"We did a deep dive through over 1,100 treatments across preclinical models and never found results where the tumors shrank away and disappeared like ours did," said Schaal. “When the rest of the literature is saying that what we're seeing doesn't happen, that's when we knew we had something extremely interesting."

The research was published in the journal Nature Biomedical Engineering.

Source: Duke University via MedicalXpress

Bravo! This makes perfect sense to me. Since the tumor is "on" 24/7, so should the treatment. Otherwise the cancer will have the edge . I would like to see even more benign substances explored within the gel that are known to be effective against cancers. That would level up the safety even higher. Wouldn't it be cool if a tiny camera could be installed so we could watch our tumors disappear on our Ipad at home :)
Very cool. But 80% of three quarters? How is this not simply 60%? I’m assuming there is some significance to this convoluted statistic - but if so it should be more explicit.
Brian M
Makes sense having the radioactive source closer to the target tissue and something that is already done for other cancers such as prostate. The idea of keeping the radioactive material within the target tissue is great,

However, what is the risk of the radiation after treatment as Iodine-131 has a half-life of about 8 days, there is still going to active material when the gel breaks down.
and the remaining Iodine 131 leaks out?

Presume most of this would be taken up by the thyroid, so a dose of Potassium iodide (KI) might reduce the risk.
People have been delivering radioactive pellets to cancers for decades. I think the difference here may be the gel, which could allow the radioactive material to infiltrate the tumor much more closely. (Which is important, because beta radiation inside a solid material is mostly absorbed within a few millimeters of the source.)
Fantastic science, I hope I live long enough to see a cure for all cancers.
My father had his prostate cancer treated successfully with a radioactive seed injected into the organ back in the late '70s/early '80s, so this tech has been around for a long while.
I knew someone who wasted away of pancreatic cancer in early middle age. I'm sure he, his wife and his children would have loved to have tried this kind of treatment no matter the risks. Enough with the excessive cautiousness in running tons of studies. Don't release it to the fairly healthy, but there are more than a few gravely ill who are ready, willing and able to be test subjects.
Richard Wallace
I saw a Clip where they injected a Radio Active piece of wire into a Cancer Tumor on a Horses leg, the Growth died and fell off like a scab.
Jim B
Titanium cased implants only allow gamma rays out, which deeply penetrate and damage surrounding healthy tissue. These gel cased radioactive implants allow beta radition out, which does not penetrate and damage the surrounding tissues. I assume they get around the gamma radiation problem by being able to use less radioactive material.
Pancreatic cancer patients have a low survival rate. Instead of wasting time testing on animals I think they could find a virtually unlimited number of willing human test subjects. In fact, given the survival rates, NOT immediately testing this trial on people is criminal.

I was in a conference at Northwestern Cancer Center in Chicago just last week. We were being given our options. I actually brought up the idea of injecting a radioactive pellet into the tumor as I know it has been an effective treatment method for prostate cancer for decades. The "well-versed, knowledgeable expert" pooh-poohed the idea and moved the conversation along to chemo treatments and dealing with their horrendous side effects....
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