Ductal carcinoma in situ. A precancerous condition characterized
by the clonal proliferation of malignant-looking cells in the lining of a breast
duct with out evidence of spread outside the duct to other tissues in the breast
or outside the breast. DCIS is clearly the precursor (forerunner) of invasive breast
cancer. This is evident from the sharing of clonal chromosome changes by DCIS and
adjacent invasive cancers. In other words, invasive breast cancer evolves from DCIS.
Also called intraductal carcinoma.
The incidence of DCIS has increased greatly, thanks to the widespread use of
screening mammography. DCIS now accounts for nearly 20% of all breast cancers detected
on screening mammograms. Risk factors for DCIS include older age, benign breast
disease, an older age at the time of the first term pregnancy or nulliparity (not
having children), and a family history of breast cancer. One in 20 women with DCIS
has a mutation in the BRCA1 or BRCA2 hereditary breast cancer genes.
The crucial decision for the pathologist is to distinguish DCIS from invasive
cancer. DCIS originates in a single glandular structure but may spread within the
breast through the ductal system. Many patients with DCIS have discontinuous disease
with gaps between the tumor foci whereas high-grade DCIS tends to be continuous.
The goal in treating DCIS is to prevent local recurrence and, in particular,
invasive breast cancer. The options for surgical treatment include simple mastectomy
or breast-conserving surgery (lumpectomy). Most women now have breast-conserving
surgery in keeping with the detection of smaller DCIS lesions on mammography. However,
after breast-conserving surgery, there is a risk for recurrence of DCIS within the
breast, arising at or near the original site of the tumor.
The drug tamoxifen may be taken after surgery and radiation treatment of DCIS.
Tamoxifen, a selective estrogen-receptor modulator, reduces the risk of recurrence.
There is no role for chemotherapy in the treatment of DCIS.
medical
dictionary, online medical dictionary, medical
terminology dictionary, free online medical
dictionary, medical dictionary, online medical
dictionary, medical terminology dictionary, free
online medical dictionary, dictionary medical,
dictionary medical online, dictionary medical
terminology, dictionary free medical online,
dictionary free medical, dictionary medical
terms, dictionary drug medical medicine,
dictionary health illustrated medical nursing
profession stedmans, dictionary English medical,
dictionary medical online terminology,
dictionary encyclopedia medical online,
condition dictionary medical, dictionary
medical, dictionary drug medical, medical
dictionary software, cyclopedic dictionary index
medical tabers thumb, medical dictionary, online
medical dictionary, medical terminology
dictionary
