IVP-1 or otherwise knowns as ductal carcinoma in situ (DCIS, sometimes also known as ductal in situ carcinoma, or intraductal carcinoma in situ) is not a true cancer, its cellular structure and what is known about its natural history suggests that these lesions can become invasive over a long period of time.
In situ lesions are considered precancerous: that is, the cells, while showing atypical or ‘dysplastic’ growth, have not yet begun to divide indiscriminately or to penetrate neighboring tissue. How do doctors know that a growth is carcinoma in situ rather than an invasive carcinoma? When DCIS lesions are examined under the microscope the cells are seen to be entirely confined within the duct structure: they do not invade the walls of the ducts or penetrate into the surrounding tissue.
Invasive lesions, by contrast, are no longer ‘in place’; they are unequivocally cancerous and have actively begun growing out into the surrounding tissues. Once a tumor has become truly malignant it is described as invasive (ductal or lobular) or ‘infiltrating'(ductal or lobular). The terms ‘invasive’ and ‘infiltrating’are used interchangeably.
The general consensus is that although DCIS is not yet truly malignant, it is nonetheless treated as an early form of breast cancer. While DCIS often occurs in isolation, it can, and frequently does, occur as an element of a more complex breast cancer picture – that is, one can have areas of DCIS within and alongside a more advanced, invasive breast cancer.
Treatment for solitary DCIS usually involves conservative surgical removal (lumpectomy), sometimes (although by no means always) followed by radiation therapy. When a particularly ominous cellular structure is seen on microscopic examination of a biopsy specimen, or when there are widespread areas of DCIS within the breast, mastectomy is sometimes recommended.
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