Study Questions Early Cancer Intervention
Aggressive interventions to treat the earliest, “stage 0” breast cancers have no effect on whether a woman is still alive a decade later, according to a massive new study that tracked the trajectories of more than 100,000 women.
The study, published in the journal JAMA Oncology on Thursday, found that the risk of dying from these early cancer lesions, called ductal carcinoma in situ, is very low — only around 3.3 percent of women in the study died of breast cancer over two decades. It is the latest addition to a growing body of evidence that suggests the ability to detect these lesions through mammograms may be leading to overtreatment of breast cancer.
Women faced with these noninvasive cancers — often referred to as stage 0 — face a frightening array of options: Most undergo a lumpectomy to remove the abnormal cells, but they may also receive radiation treatment. Some may even take the extreme measure of removing one or both breasts completely. The study suggests that adding radiation to a lumpectomy may diminish the likelihood the cancer recurs but not whether women live or die.
“Many women have a visceral and immediate response: ‘Get rid of my breasts,’ ” said Steven Narod, a senior scientist at the Women’s College Research Institute at Women’s College Hospital in Toronto. “That’s really what’s happening in the last 20 years in the U.S. We have created a culture of breast cancer awareness, and we’ve created a countercultural response of fear. When you do a mastectomy you reduce the fear greatly.”
The study did find a subset of women who were at greater risk from DCIS. Young women who are diagnosed when they are under age 35 and black women have a greater chance of dying from breast cancer, the study found.
The work highlights a recurring theme in cancer research: Screening has allowed doctors to detect cancers earlier but hasn’t always enabled them to distinguish between the ones that will ultimately kill people and the ones that are benign, leading to a constant and polarizing debate about whether cancers are being overtreated and how to pull back.
The underlying question has already come up in early stage breast cancer: Studies have found that even as nearly 60,000 women undergo surgical treatment of these stage 0 cancers each year that are thought to be a precursor to full-blown disease, the number of invasive breast cancers — the ones that kill women — has not decreased.
A study published in June in the journal JAMA Surgery looked at a similar dataset and found that removing lesions from women with low-grade DCIS did not lead to improvements in survival compared with not doing surgery.
“It was a pretty provocative study for a surgeon to say there’s a subgroup of patients we shouldn’t be operating on,” said Mehra Golshan, a surgical oncologist at Brigham and Women’s Hospital.
The major flaw in these studies has been that they are retrospective, looking back at what happened to women who may have chosen different treatment for different reasons.
Right now, two studies in Europe are beginning to examine what happens when women with the same diagnosis are given different treatments: for example, if the patients are simply observed vs. given the current standard treatment.
“I think the time has come to do trials where we back away from, for example, radiation in many women and we in a meaningful way look at the question as to whether radiation adds anything to surgery,” said Eric Winer, director of the breast cancer program at Dana-Farber Cancer Institute.
The problem with that may be convincing women to accept less care.
“There are going to be a lot of women who are simply not very comfortable with that approach,” Winer said.