What is DCIS?
DCIS is a ductal cancer that has not yet penetrated the
lining of the duct. In other words, it is not invasive. In this in
situ ("in place") stage, the cancer has not spread into
the blood stream and beyond. If it is diagnosed and treated correctly,
the risk of dying from this cancer is essentially zero.
In the past, DCIS was rare—most breast cancers were found
when the tumor had grown large enough to be felt by hand. By then
it had time to spread outside the breast. But with the increased use
of mammography in the past 20 years, DCIS has become relatively easy
to detect. It appears on mammograms as a speckling of tiny white dots—clumps
of dead cancer cells that became calcified inside the ducts. Today,
about 20-30% of cancers diagnosed are DCIS. Still, in comparison to
invasive cancers, it has not had the time to be researched as extensively,
and there is some disagreement among physicians as to how to treat
Until recently, it was firmly believed that the best way to treat
DCIS was to perform a simple mastectomy. The feeling was that since
the cancer has not yet spread (remember, DCIS is in situ!) all one
had to do was remove the breast for essentially a 100% guarantee of
As lumpectomy plus radiation became an acceptable choice for invasive
breast cancer, surgeons learned that if they removed a small DCIS
tumor with a wide margin around it and treated the breast with radiation,
they can achieve a much nicer cosmetic result. But that comes at the
expense of a small chance of future local cancer recurrence. The decision
is up to the patient and her healthcare provider.
The other area where there may be a difference of opinion is radiation
therapy. This is where DCIS treatment differs from treatment of early
invasive breast cancer. A Stage I or II tumor treated with breast
conserving surgery—lumpectomy—will always be treated with
But some specialists believe that there is no need for radiating
the breast if the DCIS tumor was small, and the margins were large
and clear—in other words, if there is a fair degree of certainty
that the tumor was indeed in situ.
The reason to avoid radiating a breast after a surgical excision
of a DCIS tumor, is that if the cancer does recur, the patient will
no longer have the option of breast conserving surgery. Since radiation
therapy can be used only once on the same area of the body, the next
time, treatment will require a mastectomy, rather than a lumpectomy.
This is another dilemma that requires discussion with your healthcare
To make the decisions easier, researchers devised a system for selecting
the best treatment plan for each DCIS lesion. It is based on the size
of the tumor, the grade of the tumor cells, and the width of the margins
around the tumor.
Before surgery, an accurate mammogram is obtained, to determine
exactly the size and shape of the DCIS lesion.
The surgeon removes the tumor with a large margin of normal tissue,
striving for at least a half inch on all sides.
The radiologist takes an X-ray of the tissue removed and compares
it with the original mammogram, to ensure that the entire tumor was
removed. Im-mediately after the X-ray, while the patient is still
in the operating room, a pathologist makes numerous slices across
the tumor and examines each slice in detail. Applying black ink to
the outside of the tumor makes it easier to determine if the margins
If the tumor was small, the grade of the cells was low, and the
margins were at least 10mm (less than half an inch) there is no need
for removing additional tissue, or for radiation therapy.
If the tumor was larger, the cells more aggressive, or the margins
too narrow, then the DCIS tumor may be treated with a simple mastectomy,
or lumpectomy with radiation.
If you were diagnosed with DCIS, you may consider investing some
time into finding a medical center with an experienced team—a
surgeon, a pathologist and a mammographer who work well together in
assessing in situ tumors. In this way you will be assured of the best
chances for a successful treatment, with the least loss of breast
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