What is the difference between invasive ductal carcinoma and ductal carcinoma in situ (DCIS) of the breast and how are they treated?
A Invasive ductal carcinoma is referred to as cancerous cells having crossed the basement membrane of the ducts lining the breast giving it access to the lymphatics, whereas, in situ disease remains confined within the basement membrane so it does not metastasize. Both of these require surgical excision with “clean” margins; however, invasive disease necessitates biopsy of axillary lymph nodes for staging purposes. Invasive disease often requires chemotherapy. Radiation therapy may be recommended in both, especially in cases of breast conserving therapy. Both invasive and in situ require extremely close follow-up for years to come with possible addition of risk reduction therapies such as Tamoxifen. Genetic testing may also be obtained depending on age and family history.