According to the NIH Consensus Conference, if DCIS is allowed to go untreated, the natural course or natural history varies according to the grade of the DCIS. Unless treated, approximately 60 percent of low-grade DCIS lesions will have become<unk>  at 40 years follow-up. High-grade DCIS lesions that have been inadequately resected and not given radiotherapy have a 50 percent risk of becoming<unk>  breast cancer within seven years. Approximately half of low-grade DCIS detected at screening will represent overdiagnosis, but overdiagnosis of high-grade DCIS is rare. The natural history of intermediate-grade DCIS is difficult to predict. Approximately one-third of malignant calcification clusters detected at screening mammography already have an<unk>  focus. The prognosis of IDC depends, in part, on its histological subtype. Mucinous, papillary, cribriform, and tubular carcinomas have longer survival, and lower recurrence rates. The prognosis of the most common form of IDC, called "IDC Not Otherwise Specified", is intermediate. Finally, some rare forms of breast cancer (e.g., sarcomatoid carcinoma, inflammatory carcinoma) have a poor prognosis. Regardless of the histological subtype, the prognosis of IDC depends also on tumor size, presence of cancer in the lymph nodes, histological grade, presence of cancer in small vessels (vascular invasion), expression of hormone receptors and of oncogenes like HER2/neu. These parameters can be entered into models that provide a statistical probability of systemic spread. The probability of systemic spread is a key factor in determining whether radiation and chemotherapy are worthwhile. The individual parameters are important also because they can predict how well a cancer will respond to specific chemotherapy agents. Overall, the five-year survival rate of<unk>  ductal carcinoma was approximately 85% in 2003.
Invasive carcinoma of no special type
Verrucous carcinoma
Basal-like carcinoma
Lymphoepithelioma-like carcinoma
Mucinous carcinoma
Sarcomatoid carcinoma
Ductal carcinoma in situ
Carcinoma ex pleomorphic adenoma