Ductal carcinoma in situ or DCIS accounts for roughly 15-20% of new breast cancer diagnoses each year. It is considered noninvasive breast cancer, which means that it does not have the ability to spread to the lymph nodes under the arm or other parts of the body. Because it is a local disease (only involving the breast), standard treatment options are directed at the breast and may include surgery, radiation, and/or endocrine therapy.
Treatment decisions are usually based on tumor biology, extent of disease, and other factors, such as breast anatomy and patient preferences. Surgery and radiation are used to remove the disease in the breast and to prevent recurrence. Endocrine therapy may also be considered.
Surgery is the mainstay of treatment for DCIS, and surgical options may include lumpectomy or mastectomy. Factors influencing the surgical decision include: extent of DCIS, location in the breast, cosmetic outcome, ability to have radiation, presence of a genetic mutation, and patient preference.
For many patients, lumpectomy is sufficient and recommended to remove DCIS. If it cannot be felt on exam, it will need to be localized to direct the surgeon to the area of DCIS. Lymph node surgery is rarely recommended when a lumpectomy is performed for DCIS.
Some women are not eligible for lumpectomy, and mastectomy may be recommended. Also, mastectomy may be preferred by some patients. Mastectomy involves removal of all breast tissue, but can often be performed as a skin-sparing or nipple-sparing procedure with reconstruction. With a mastectomy, lymph node surgery may be considered.
If a woman is eligible for a lumpectomy, there is usually no difference in survival between lumpectomy and mastectomy. One exception may be a woman with an inherited genetic mutation that may increase her risk of recurrent breast cancer. Some women may also consider having the opposite breast removed (contralateral prophylactic mastectomy), but this has not been shown to improve survival for most women.
Many women who have a lumpectomy will require radiation. If a mastectomy is done, radiation is usually not recommended for DCIS. Factors influencing the radiation decisions are similar to those for surgery and may include: tumor size, type of surgery performed, prior radiation or other contraindications to radiation, patient medical conditions, patient age and patient preference. Some women with low risk DCIS may consider omitting radiation therapy, but should discuss these options with the treating physicians.
For a woman with hormone receptor positive DCIS, she may be offered endocrine therapy to reduce her risk of breast cancer recurrence. Options may include an aromatase inhibitor, such as Arimidex, or Tamoxifen.
What if I do nothing?
Based on existing data, observation alone is not recommended as a standard treatment option for DCIS, although ongoing clinical trials are currently evaluating the safety of observation alone in women who are felt to have low risk DCIS. If left untreated, DCIS may progress to invasive breast cancers and then require treatment.
1) American Cancer Society. Breast Cancer Facts & Figures 2015-2016. Atlanta: American Cancer Society, Inc. 2015.
2) Obeng-Gyasi S, Ong C, Hwang ES. Contemporary management of ductal carcinoma in situ and lobular carcinoma in situ. Chin Clin Oncol. 2016 May 11. [Epub ahead of print]