Nuclear Waste May Help Cancer

["Sandy Perle" <sandyfl@earthlink.net>]

Sunday July 30 12:00 PM ET

Nuclear Waste May Help Cancer 

OAK RIDGE, Tenn. (AP) - Locked away for more than 40 years in guarded 
concrete vaults at the Oak Ridge National Laboratory may be the key 
to a promising new therapy for cancer patients. 

The lab's 11/2-ton cache of weapons-grade uranium-233, until now 
considered waste, is the nation's only readily available source for a 
potent isotope that can kill leukemia cells without harming healthy 
cells. 

``It is kind of like a little bomb going off that you can target 
right to that cancer cell,'' the lab's program manager Jim Rushton 
said. 

Researchers at Memorial Sloan-Kettering Cancer Center in New York are 
developing the ``alpha particle immunotherapy'' and last year 
completed initial human tests. 

The isotope bismuth-213 was attached to an antibody designed to carry 
the alpha-emitting isotope to the cancer. The tests were to see if 
the treatment did more harm than good in acute myeloid leukemia 
patients. 

The results were a surprise. Not only was the therapy safe, but 
leukemia cells were eliminated in the blood stream and reduced in the 
bone marrow of 13 of the 18 patients taking part, said Dr. Joseph 
Jurcic, one of the researchers. 

``We really think it has broad implications for the whole field of 
oncology, not just for leukemia,'' he said. 

The researchers don't envision bismuth therapy replacing chemotherapy 
or surgery. Rather they see its potential in ``cleaning up residual 
cancer cells that are remaining behind after primary treatments,'' he 
said. 

This is no small challenge. Jurcic said only 30 percent to 40 percent 
of acute leukemia patients are cured by chemotherapy. 
``The majority of these patients go into remission with chemotherapy, 
but they relapse because of these residual cells. That's where we 
think the bismuth is going to be particularly useful.'' 
This fall, Sloan-Kettering, under the watch of the National Cancer 
Institute, plans to start a second phase of testing with 35 to 40 
patients to measure the therapy's effectiveness. The trials could 
last three years. 

``The advantage of alpha-emitters is that they deposit a large amount 
of energy in a very small area of tissue,'' said Dr. Jorge 
Carrasquillo, deputy chief of nuclear medicine at the National 
Institutes of Health. 

Attaching the bismuth to antibodies that can carry the radiation dose 
straight to diseased cells is an ``innovative treatment,'' and Sloan-
Kettering is leading the way, he said. 

``Of course it is too early to tell the final role,'' Carrasquillo 
said, ``but it certainly is a strategy worth pursuing.'' 
The problem was getting more bismuth-213, an exotic isotope with a 46-
minute half-life, which makes it perfect for injecting into patients 
because it quickly dissipates but makes it difficult to acquire. 
Bismuth-213 can be obtained in what physicists describe as a decay 
chain from uranium-233. First, thorium-229 is extracted, then 
actinium-225 is taken from that and then the bismuth is extracted 
from the actinium. 
The search for thorium led to the uranium-233 stockpile in Oak Ridge. 
Energy Secretary Bill Richardson agreed last month at the behest of 
Sen. Fred Thompson, R-Tenn., and Rep. Joe Knollenberg, R-Mich., to 
double the supply of bismuth-213 by 2002 for the Sloan-Kettering 
research. 

Rushton said only 1 percent of the available bismuth-213 has been 
recovered from Oak Ridge. The total of bismuth-213 there is 
infinitesimally small - so small that it is measured by its 
radioactivity instead of its weight. 

A typical shipment to Sloan-Kettering ``is literally a spot of 
material that is dried in the bottom of a vial. It looks like the 
vial is empty,'' Rushton said. 

But researchers believe there is enough high-powered bismuth-213 at 
Oak Ridge to treat up to 100,000 cancer patients a year. 
Oak Ridge's uranium-233 was made at the government's weapons fuel 
production plants in South Carolina and Washington state in the 1950s 
and 1960s. However, it was never intended for bombs, rather to fuel 
commercial nuclear plants. 

At the time, uranium sources were scarce and nuclear power generation 
looked full of promise. 

``But nuclear power did not grow as rapidly as the too-cheap-to-meter 
advocates had said, and people found all kinds of uranium out 
there,'' Rushton said. ``The price fell and the economic need for 
this as an alternative fuel never developed.'' 

And so the uranium-233, considered more hazardous than enriched 
uranium for weapons - which also is stored in Oak Ridge - has 
remained at the Oak Ridge lab complex. It costs $15 million a year to 
store, and some experts estimate it will cost even more to dispose 
of. 

Although the bismuth extraction will not reduce the volume of uranium-
233, it at least gives value to the uranium's manufacture, Rushton 
said. 

``We spent a lot of money making this stuff,'' he said. ``If we had 
disposed of all this 10 years ago, we wouldn't have the option to 
look at bismuth-213 today.''

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Sandy Perle					Tel:(714) 545-0100 / (800) 548-5100   				    	
Director, Technical				Extension 2306 				     	
ICN Worldwide Dosimetry Division		Fax:(714) 668-3149 	                   		    
ICN Biomedicals, Inc.				E-Mail: sandyfl@earthlink.net 				                           
ICN Plaza, 3300 Hyland Avenue  		E-Mail: sperle@icnpharm.com          	          
Costa Mesa, CA 92626                                      

Personal Website:  http://www.geocities.com/capecanaveral/1205
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