Patients, Doctors Overrate DCIS Risk
Ductal Carcinoma in Situ: High Anxiety Over Small Risk of Invasive Breast Cancer
WebMD News Archive
Low-Risk Breast Cancer -- Except When It's Not
DCIS is ductal carcinoma in situ. The "carcinoma" part is truly
scary. Just as it sounds, it means cancer. But the "in situ" part is
every bit as important. It means that this cancer isn't going anywhere. DCIS
is, by definition, confined to the breast ducts. It does not invade the rest of
the breast, or the rest of the body.
It's very unusual for either women or their doctors to feel DCIS, as it
rarely is large enough to cause a lump. Nearly all DCIS is detected during
routine screening mammograms.
This doesn't mean DCIS is never a problem. About one in 100 women with DCIS
actually has invasive cancer cells lurking in her breast ducts, says Partridge.
So why are virtually all women with DCIS treated?
"Until you take it all out, you can't know it is only DCIS,"
Partridge tells WebMD. "In some ways it is incumbent on us as oncologists
to take it out to prove it is only DCIS. It is hard to predict who is just DCIS
and who is having invasive cancer cells hiding in the DCIS."
And if DCIS comes back, which happens less than 10% of the time, Partridge
says there's a 50-50 chance it will come back as invasive cancer.
This makes it sound as though doctors fully understand DCIS. They don't.
Doctors treat DCIS when they see it, so nobody is really sure what happens to
One thing that is sure is that some women treated for DCIS would never have
had serious breast cancer if their DCIS had not been detected, notes H. Gilbert
Welch, MD, MPH, director of the VA outcomes group at the Veterans Affairs
Medical Center in White River Junction, Vt.
"We know that mammography detects more cancers than would ever become
clinically evident," Welch tells WebMD. "You cast a wide net to find
early cancers, and that net catches a lot more women than ever would have
clinically significant cancers."
"For every 1,000 women in their 50s who undergo a 10-year course of
annual mammography, under a best-case scenario, two would avoid a breast cancer
death or have a breast cancer death delayed -- that is the credit side of the
balance sheet," Welch says. "On the debit side, 250 to 500 of these
women will have at least one false-positive result they will worry about. And
about four of these women will be diagnosed with breast cancer unnecessarily --
four women will be overdiagnosed."
DCIS is the poster child for this dilemma, Welch suggests in an editorial
accompanying the Partridge report in the Feb. 20 issue of the Journal of the
National Cancer Institute. He says women with DCIS are anxious because
doctors really don't know what to tell them. He suggests there should be a
clinical trial of withholding biopsy until DCIS lesions are large enough to