Canadian study suggests less breast cancer treatment may be just as effective, with fewer side effects – CTV
June 23, 2026
A Canadian-led study is challenging a long-standing assumption in cancer care: that more treatment is always better.
Researchers say their findings could change how an estimated two million women with early-stage breast cancer are treated each year, around the world and in Canada.
“The results have been an absolute slam dunk, affecting the care of around 30,000 Canadian patients a year and two million patients globally every year,” said Dr. Mark Clemons, an oncologist at the Ottawa Hospital, and a member of the study team.
The study, published in the Journal NEMJ Evidence, was conducted at several hospitals in Ontario. It didn’t test a new drug or a more intensive or powerful treatment regimen. Instead, it tested something far simpler: whether patients could safely receive far less treatment with a similar long-term effect.
The answer, researchers say, appears to be yes. And one of the test subjects, Beth Ciavaglia, of Ottawa, applauds the results.
