Nightly News | June 02, 2012
>>> we're back with big health news out of this weekend's meeting of more than 40,000 cancer doctors. tonight, there's a promising new study getting a lot of attention. doctors hope it could lead to a new attack against some of the deadliest forms of cancer . we get more from our chief science correspondent, robert bazell .
>> reporter: it is a new approach using the body's immune system to kill cancer . it helped david, a retired baltimore policeman who had advanced lung cancer .
>> i was at basically looking at living month to month.
>> reporter: scan shows tumor, seen here melting away over a period of months. ken kirkwood, who had advanced kidney cancer , saw similar results.
>> i couldn't believe it, but in about four or five months or so, i was starting to see shrinkage in my limp nodes and my lungs and the area where the kidney had been removed.
>> reporter: doctors also saw positive results with advanced melanoma.
>> there is a common denominator for many kinds of cancer . this is really unprecedented. there are so many exciting opportunities.
>> reporter: the treatment is in its earliest phase.
>> typically in a phase one trial, you don't expect much, but we saw activity, so some tumor, completely shrinking away.
>> reporter: here's how it works. white blood cells , which kill bacteria and viruses, often try to kill cancer cells , but the cancer puts up a barrier. the treatment is designed to bring that barrier down. tumors shrank in 18 to 28%, depending on the type of cancer . at this weekend's conference, planning is underway for bigger trials, comparing and looking at side effects . for more than a century, scientists have been working to harness the body's immune system to fight cancer . only now is that starting to pay off.
>> i just wanted to live long enough for the cure and maybe i have. maybe i'm part of it.
>> reporter: while it's not a cure, for many, it's a hopeful beginning. robert bazell , nbc news, chicago.