Doctors Use Genetics To Find The Right Key To Unlock Cancer Treatment
Advances in technology are changing some of the basic questions doctors ask when treating cancer.
“Does it matter if it's breast or lung or colon or leukemia - should we be treating tumors based on their mutations and not on their tissue of origin?” says Dr. Stan Lipkowitz of the National Cancer Institute.
Doctors in Charlotte and across the country are in the early stages of answering those questions. They’re focusing on the genetic mutations thought to be driving someone’s cancer, rather than the place it started.
For some patients in Charlotte, the results of this treatment have been remarkable.
Lung cancer took a tremendous toll on Edwina Edgeworth. In about two years, she went from someone who ran 3 miles a day to someone who could barely stand.
“I didn't have the strength in my legs to hold me up,” she says. “They just felt like numb, felt like rubber, and I just couldn't stand on my own. I went about two weeks like that.”
In the lobby of the Levine Cancer Institute in Charlotte, her son Ronnie says she’s always been tough, but it was like watching her wither.
“Seeing my rock, you know, my mom, being so weak, it was very upsetting for me to see her going through that,” he says.
The cancer spread to her brain and liver. Her medicine stopped working, and another kind of treatment didn’t help.
About a year ago, Edgeworth joined a study that took a different approach. Doctors analyzed the genetics of her tumor and then took aim at a specific mutation.
Now, Edgeworth is back on her feet, and her cancer is steadily shrinking.
“Every time I go back, it's shrunk a little bit more and a little bit more,” she says. “Right now it's cleared up pretty much in the lung. I just have something left in my liver.”
It’s a result that Dr. Edward Kim at the Levine Cancer Institute describes as “amazing.”
He says this is the new era of research: combining genetic testing with drug development to target specific genetic markers. In simple terms, it’s like finding the right key for a lock.
“Now what we're seeing more and more of are these specific marker-targeted therapies, where we measure the marker in the cancer, we have the therapy, and we see just dramatic changes,” Dr. Kim says. “We see tumors even disappearing.”
At UNC-Chapel Hill's Lineberger Comprehensive Cancer Center, Dr. Juneko Grilley-Olson has seen similar results.
“It's encouraging when you see somebody whose cancer has failed to respond to sort of standard treatments and then have their cancer respond because you were able to select the treatment more tailored to their cancer itself,” she says.
Gene-targeted therapy in itself isn’t that new. Doctors have used it for certain kinds of cancer for about 15 years. But Dr. Grilley-Olson says the practice has ramped up in the past five or so years as gene-sequencing technology has taken off.
“Back in the ‘90s,” she says, “there was the Human Genome Project, where it took the better part of a decade to sequence one human's entire genome.”
Think: all of the DNA in one person, decoded.
“Now that can be done in a week and can be done in a week for probably under $1,000,” Dr. Grilley-Olson says.
That leap in technology and drop in cost means this is now an option for far more patients.
It also means it’s now much easier to identify mutations, even in rare cancers. But Dr. Stan Lipkowitz of the NCI says researchers are still figuring out which mutations matter.
“Do all cancers with a certain mutation respond to treatment targeting that?” he says. “Or another possibility would be that lots of cancers have the same mutations, in some they respond dramatically, in others they may not.”
In other words, just because you can find the right key for a lock, that doesn’t mean opening the lock would help.
The National Cancer Institute is launching a study this year to find more answers. It’ll analyze genetic mutations in tumors from as many as 3,000 patients.
At the Levine Cancer Institute in Charlotte, Dr. Kim says around 100 patients are in a gene-targeted study at any given time. They’re usually the sickest patients – they’ve exhausted standard treatments – and the new approach often isn’t the answer.
“But even if you get one success out of 10, you've moved the needle personally for that patient, and that's going to encourage other investigators and the government and companies to pay more attention to this therapy, this marker,” Dr. Kim says.
There’s another big advantage to this over traditional chemotherapy delivered through IVs: the gene-targeted medicines are often pills, with very few side effects.
Edwina Edgeworth’s original medicine led to nasty blisters on her face and entire body. Since she switched to the gene-targeted drug, “I've had no side effects, close to normal life.”
“Everything's been great,” she says. “I have no complaints.”
Her cancer treatment now consists of one pill, once a day.