While the authors caution that longer follow-up will be required before a definitive conclusion can be reached regarding long-term toxicity, they point out that ongoing technical improvements should further restrict radiation exposure in healthy tissues. They do recommend that comprehensive information on potential side effects is given to women who receive this treatment. The addition of radiation therapy to lumpectomy appears to reduce the risk of local recurrence to approximately 12%, of which approximately half will be DCIS and half will be invasive breast cancer; the risk of recurrence is 1% for women undergoing mastectomy. Mastectomy
There is no evidence that mastectomy decreases the risk of death over a lumpectomy. Mastectomy; however, may decrease the rate of the DCIS or invasive cancer occurring in the same location.Mastectomies remain a common recommendation in those with persistent microscopic involvement of margins after local excision or with a diagnosis of DCIS and evidence of suspicious, diffuse microcalcifications. Sentinel node biopsy
Some institutions that have encountered high rates of recurrent invasive cancers after mastectomy for DCIS have endorsed routine sentinel node biopsy (SNB). However, research indicates that sentinel node biopsy has risks that outweigh the benefits for most women with DCIS. SNB should be considered with tissue diagnosis of high risk DCIS (grade III with palpable mass or larger size on imaging) as well as in people undergoing mastectomy after a core or excisional biopsy diagnosis of DCIS. Prognosis
With treatment, the prognosis is excellent, with greater than 97% long-term survival.
In a few cases, DCIS may cause:

A lump or thickening in or near the breast or under the arm
A change in the size or shape of the breast
Nipple discharge or nipple tenderness; the nipple may also be inverted, or pulled back into the breast
Ridges or pitting of the breast; the skin may look like the skin of an orange
A change in the way the skin of the breast, areola, or nipple looks or feels such as warmth, swelling, redness or scaliness. Causes
The specific causes of DCIS are still unknown. The risk factors for developing this condition are similar to those for invasive breast cancer.Some women are however more prone than others to developing DCIS. Women considered at higher risks are those who have a family history of breast cancer, those who have had their periods at an early age or who have had a late menopause. Also, women who have never had children or had them late in life are also more likely to get this condition. Long-term use of estrogen-progestin hormone replacement therapy (HRT) for more than five years after menopause, genetic mutations (BRCA1 or BRCA2 genes), atypical hyperplasia, as well as radiation exposure or exposure to certain chemicals may also contribute in the development of the condition. Nonetheless, the risk of developing noninvasive cancer increases with age and it is higher in women older than 45 years. Diagnosis
80% of cases in the United States are detected by mammography screening. More definitive diagnosis is made by breast biopsy for histopathology.