SEATTLE Since 1980, the incidence of ductal carcinoma in situ, or DCIS, one of the most common kinds of early stage breast cancer, has increased more than sevenfold. This sharp increase in DCIS which is a tumor that contains cancer-like cells but is not considered "true" cancer because the cells have not invaded normal breast tissue has been accompanied by a flattening in the incidence of true invasive breast cancer.
Both trends suggest that widespread mammography screening, along with improvements in imaging technology and increased biopsy rates, among other factors, are catching breast cancer earlier, before it starts to spread and becomes more life-threatening, according to a new study by Christopher Li, M.D., Ph.D., and colleagues at Fred Hutchinson Cancer Research Center, published in the April issue of Cancer Epidemiology, Biomarkers and Prevention.
"The results of this study suggest that our public-health efforts to increase the use of breast-cancer screening mammography, primarily appear to have altered the types of breast cancer that are being diagnosed most frequently in the United States, as we have found that the number of invasive cases being diagnosed has stabilized, while more cases of in situ breast cancer are being diagnosed," said Li, an assistant member of Fred Hutchinson's Public Health Sciences Division.
Li and colleagues also found a sixfold increase in a less aggressive form of ductal carcinoma in situ, a condition called noncomedo DCIS, while incidence rates of a potentially more aggressive type, called comedo DCIS, have declined during the last five years.
"This suggests a further downshifting of severity within in situ cancers themselves," Li said.
The researchers also found that rates of a less common precancerous condition called lobular carcinoma in situ, or LCIS, has increased nearly fourfold in postmenopausal women since 1980.
These findings, based on the most comprehensive assessment to date of age-sPage: 1 2 3 Related medicine news :1
Contact: Kristen Lidke Woodward
Fred Hutchinson Cancer Research Center
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