Early stage breast cancers known as DCIS (ductal carcinoma in situ) should
be treated with surgery, not a "wait-and-watch" approach, according
to new research.
Experts have debated whether to treat early DCIS or simply monitor it to
see if it progresses. The new study suggests excision of DCIS -- cancer
confined to the milk ducts in the breast -- is best in nearly all cases.
"Regardless of [tumor] grade, surveillance alone without surgery is
not adequate," said Dr. Sadia Khan, advisor to the breast cancer
program at Hoag Memorial Hospital Presbyterian in Newport Beach, Calif.
She presented the study results Thursday at the American Society of Breast
Surgeons meeting in Dallas.
Grade describes the degree of tumor-tissue abnormality and how likely it
is to grow. Lower grades have better outlooks.
With treatment, survival from DCIS is nearly 100 percent, Khan said. However,
if the cancer recurs, it can become invasive and life-threatening.
For the study, Khan and her colleagues divided 720 patients with DCIS into
two groups. Nearly 600 of the women had the tumor excised, with clear
(cancer-free) margins of 1 millimeter or more after surgery. Those women
were compared with 124 whose margins were less than 1 mm. These women
declined a recommended second surgery. A margin of 2 mm of normal tissue
around the tumor site is a common goal.
Those who declined the second surgery served as a surrogate for an observation-only
group in the study.
After 10 years, about two-thirds of those with margins of less than 1 millimeter
had a local recurrence, compared to up to 46 percent of those in the group
with broader margins, the study found.
Recurrence was defined as the cancer returning to the original site.
Even in those who had the very earliest DCIS, with the lowest grades, the
recurrence rate was 53 percent in those with margins less than 1 mm. The
researchers termed this rate "too high" to be considered adequate
treatment.
In comparison, only 13 percent of those with the very earliest DCIS and
margins of more than 1 millimeter had recurrence after 10 years, the study found.
"Doing a needle biopsy and just watching someone with a mammogram
is inappropriate and unacceptable for DCIS," Khan said.
The study adds "very important information" for women who want
to know their recurrence risk, and talk to their doctors about what to
do and decide what risk they are comfortable with, said Dr. Linda Bosserman.
She is a clinical assistant professor at the City of Hope Medical Group
in Rancho Cucamonga, Calif. She played no role in the study.
Depending on a woman's preferences and other medical conditions, she
said, some women may accept a relatively low risk of recurrence. Adding
radiation after surgery can reduce the recurrence risk of DCIS even more,
Bosserman pointed out.
The study adds good information doctors can pass on to patients, she said.
"We can now better advise our patients, based on this study, that
if they have low grade (1-2) DCIS [the earliest grade] with less than
a 1 mm margin, they would have an 18 percent chance -- or about a one
in five chance -- of having their breast cancer recur in five years,"
Bosserman said.
Over 10 years, their recurrence risk rises to about one in two, she added.
Another expert, Dr. Julie Margenthaler, professor of surgery at Washington
University in St. Louis, said that the study reinforces the concept that
"for the vast majority, the standard surgical excision [of DCIS]
is still the appropriate course of treatment." Margenthaler wasn't
involved in the new study.
"There are select patients who may be eligible for observation alone.
But that should be closely monitored," she said. Ideally, they should
be in a clinical trial, Margenthaler suggested.
Data and conclusions presented at meetings are usually considered preliminary
until published in a peer-reviewed medical journal.
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