Fighting back
Doctors turn the body’s own immune systems against deadly cancers
As a farm girl in Middle Musquodoboit in the 1950s, Carol Peterson spent many hours roaming the fields and woods under the hot summer sun.
The oldest of 13 kids, she and her siblings walked most days through the hay field to the Musquodoboit River and often jumped on the hay trailer for a ride back to the barn.
“And that’s how we spent all summer,” said Peterson, 74, in an interview from her home near Shortts Lake in Brookfield.
But as an extremely fairskinned person, the effects of those sun-soaked halcyon days have taken a terrible toll on her health. About 20 years ago, the first carcinomas started to appear.
“My dermatologist, the first one I had, … told me it takes 30 years to make a basal cell carcinoma,” Peterson said. “It’s in the bottom of your skin from sun damage and it just works its way up to the top. … The first sign of it is a scaly red spot and he said as many as he takes off, there’ll be one from the next year and the next year and they’re just going to keep popping up forever.”
Peterson has had as many as 21 carcinomas removed in one session.
She’s also fought a more serious and rare type of cancer called squamous cell carcinoma. These aggressive growths appeared about five years ago after she scraped her toe on a table while vacationing in Florida.
“It just looked like a wound on my toe. I should have clued in because it didn’t get better,” she said. “It bubbled all up, I described it like you stepped on a grape and broke the skin. The inside of the grape pops out, well that’s exactly what it was like.”
About a month later, she developed a growth in the lymph node of her upper thigh.
"Once it gets into the bloodstream . . . it can travel through the lymph nodes all over your body."
From Florida, she contacted family friend and surgeon Roderick McKenney, who urged her to come home to get the lymph node growth removed.
MRI and CAT scans done in Florida had indicated the growth was only walnut-sized so McKenney decided on a day surgery with local anesthetic in the Truro hospital.
But the tumour had grown significantly in the meantime, which led to a traumatic situation given Peterson was awake.
“(The surgeon) looked at me and said, ‘oh Carol, you should be up in the operating room, there’s a lot more here,’ ” she recounted. “It was terrifying. By the time he got that far and told that to me, I was starting to wince because every time he cut or snipped or whatever he was doing, I could feel it.”
McKenney had no choice but to continue with the operation and Peterson endured the procedure with the help of more local anesthetic.
Peterson’s complex case was passed along to Halifax oncological surgeon and researcher Carman Giacomantonio. In addition to traditional surgery techniques, Giacomantonio asked Peterson if she would be interested in a more experimental approach that uses the body’s natural immune response system to attack cancer cells.
Giacomantonio injects a drug called interleukin 2 into the tumours.
“Interleukin means between white cells, it’s one of the molecules that white cells, or your immune system, uses to communicate with each other,” he said in a recent interview. “So this thing was identified as being critical to initiate the big immune response we need to overcome cancers and melanoma is one of the cancers that we’ve recognized for many, many years is immunogenic. In other words, sometimes melanomas disappear just because the immune system deals with it.”
This treatment first emerged in the 1980s and has been refined over the decades to reduce toxic side-effects. Peterson said she endured “horrible” nausea and fatigue for about a day after her injections, but in the early days virtually most patients ended up in intensive care, Giacomantonio said.
Immunotherapy is also more effective these days because clinicians can pinpoint specific proteins in a patient’s tumour with an instrument called a mass spectrometer.
“We’ve treated about 50 patients over the last number of years, and about 70 per cent of those patients respond (and)
“We’ve treated about 50 patients over the last number of years, and about 70 per cent of those patients respond (and) over half of them are actually cured from just the injection of the interleukin 2. I can tell you 10 years ago, this (melanoma) was a lethal disease. Every one of these patients would die.” Dr. Carman Giacomantonio
over half of them are actually cured from just the injection of the interleukin 2,” Giacomantonio said. “I can tell you 10 years ago, this (melanoma) was a lethal disease. Every one of these patients would die.”
Immunotherapy has also proved effective for his squamous cancer patients like Peterson. The tumour in her toe disappeared only three weeks after he injected it.
“It had all new pink skin on it, it was the best-looking toe on my foot,” Peterson marvelled.
More local cancer patients could benefit from immunotherapy if the purchase of a cutting edge mass spectrometer goes through.
The Orbitrap Fusion spectrometer, which costs $1.2 million, can analyze tumour targets with incredible accuracy, Giacomantonio said.
“The hope is we can then focus on the people that aren’t responding and understand what the difference in those proteins are and generate better antigen stimulants for the immune system from the differences that we see.”
The spectrometer project is part of the Dalhousie Medical Research Foundation’s annual Molly Appeal fundraising campaign this year.
Peterson has gone public with her story not only to support this campaign but to get the message out that people must protect themselves from the harmful ultraviolet radiation that goes hand-in-hand with fun in the sun.
“I know a lot of young people don’t pay attention,” she said, particularly fair-skinned people like her. “Wear a hat and cover up.”