Ductal carcinoma in situ (DCIS), also known as intraductal cancer, is cancer development from the epithelial cells lining the milk duct of the breast.
It’s considered to be “Stage 0” breast cancer, meaning there’s no invasive component. “The cancer cells do not spread from their original site, through the wall of the milk duct, to any place outside,” explains. Ching Ho MD, of the TriHealth Cancer Institute. And, due to the non-invasive nature of this cancer, there has been a lot of controversy, lately, about how to treat it.
How to Detect DCIS
Because this cancer is found in the lining of the milk duct, you are not likely to catch it through a self-breast examination, but instead, through a mammogram.
“These types of cancer – some, not all of them – grow and form calcium deposits along the milk duct, and these specific patterns of calcification can be seen on mammograms in about 90 percent of intraductal carcinoma cases,” Dr. Ho explains.
My Doctor Detected DCIS: Now What?
Decades ago, surgeons would perform a mastectomy (surgical removal of the entire breast) to take out the cancerous tissue right away; however, today, that’s not the case.
Now, surgery is recommended with more caution. Once your doctor does a needle biopsy and determines that you have an intraductal carcinoma inside your breast, he or she will look at the mammogram again, or order an MRI to see if the disease is dispersed. Your doctor may also suggest DNA or genomic tests to guide the best treatment.
If your surgeon finds that the intraductal cancer has an invasive component, when making the final diagnosis, then further treatment options may be needed. A mastectomy is suggested if the cancer is in a large area of the breast.
In older patients, if the intraductal cancer is low-grade, the cancer will likely be removed through a lumpectomy and, from there, the patient will be closely monitored.
DCIS: Is Preventative Medication the Way to go?
Dr. Ho reminds people that maintaining good health, through a nutritious diet and regular exercise, is one of the best things you can do for cancer prevention overall. When it comes to preventing cancer, medication-wise, she stresses the importance of weighing the risks and benefits.
“If you look at prevention studies, if somebody is 65 or older, the chances they get cancer in the next five years is 1.65 percent,” Dr. Ho points out. “With that risk, if you give them tamoxifen, the preventive drug, it will reduce that risk by half. It will be .8 percent … very few woman are going to take that pill for five years for a decreased .8 percent risk.”
Tamoxifen can also have negative side effects, like worsening post-menopausal symptoms, as well as increasing the risk for uterine cancer and blood clots.
"It's important to weigh the risks and benefits of taking this medication, and take into consideration how this will impact quality of life," Dr. Ho explains.