Ductal Carcinoma in Situ is diagnosed by examination of the biopsy of breast tumor. The cancer cells are within the milk ducts and have not invaded the underlying tissue. It is classified as Stage 0 breast cancer. The incidence of DCIS has increased with the widespread use of screening mammography and it now accounts for 20-30% of all newly diagnosed breast cancers.
The treatment of DCIS has become controversial. Even the name is a source of controversy. Some believe it should not be called cancer at all, since it doesn’t involve tissue invasion. The problem with DCIS is that somewhere between 25-50% of cases will progress to invasive disease.
Because of this progression, most patients with DCIS are undergoing surgery—either mastectomy or lumpectomy with radiation. A recent study in JAMA Surgery looked at the outcomes of women who did not have surgery, but instead were followed by active surveillance. (JAMA article: http://archsurg.jamanetwork.com/article.aspx?articleID=2300045&utm_source=Silverchair%20Information%20Systems&utm_medium=email&utm_campaign=ArchivesofSurgery%3AOnlineFirst06%2F03%2F2015)
Articles in The New York Times (http://www.nytimes.com/2015/09/29/health/a-breast-cancer-surgeon-who-keeps-challenging-the-status-quo.html ) and Time magazine (http://time.com/4057310/breast-cancer-overtreatment/ ) both quote practitioners who advocate renaming DCIS as well as changing to non-operative management of the disease.
The surgeons followed in these articles, Dr. Laura Esserman of UCSF and Dr. E. Shelley Hwang of Duke, propose DCIS should be renamed “IDLE, indolent lesions of epithelial origin”. They believe many women are erroneously deciding on aggressive treatments just because they are frightened and reacting to the word “carcinoma.” Dr, Esserman follows many DCIS patients with active surveillance. They receive yearly mammograms alternating with MRI’s. Depending on receptor status of their tumors, some undergo ovarian suppression and hormonal therapy.
But many cancer specialists believe the aggressive treatments are warranted since DCIS can progress to invasive cancer. They believe we don’t know enough to determine which cases of DCIS will progress and because of this we should continue to treat all cases of DCIS.
The JAMA study has again sparked the debate on how DCIS should be treated. It was
a retrospective study of 57,222 American women with DCIS that showed no survival benefit from surgery in women with low-grade disease. (Tumor grade is the description of a tumor based on how abnormal the tumor cells and the tumor tissue look under a microscope. It is an indicator of how quickly a tumor is likely to grow and spread.) 1169 patients with DCIS in 10 health districts were managed without surgery from 1988 to 2011 and entered into the logs of Surveillance, Epidemiology and End Results (SEER) database. These exceptional cases were compared with the 56,053 patients who were treated with surgery.
They found that 10-year breast-cancer-specific survival was significantly better in patients with intermediate- and high-grade disease who had undergone surgery than in those who had not. For intermediate grade DCIS, there was an absolute difference in weighted 10-year breast-cancer-specific survival of 4.0% between the surgery and nonsurgery groups (98.6% vs 94.6%); for high-grade DCIS, there was an absolute difference of 7.9% (98.4% vs 90.5%).
But for women with low-grade DCIS, surgery appeared to be superfluous. Ten-year breast-cancer-specific survival was the same for patients who underwent surgery and for those who did not (98.8% vs 98.6%; P = .95).
Most clinicians are not convinced. Some do not feel tumor grade alone is a good enough predictor of which cases of DCIS will progress. They also point out limitations in the JAMA study. For example, it is not known how many women were diagnosed with low grade DCIS on biopsy, but after surgical excision were found to have invasive cancer.
So what if you are diagnosed with DCIS? If your biopsy shows intermediate or high grade disease, surgical excision (+/-radiation and hormonal therapy) provides a higher percentage 10 year-breast-cancer-specific survival. If it’s low grade DCIS, the decision is a bit more difficult. There is a test available called the Oncotype DX DCIS test. This test is a genomic test that analyzes the activity of a group of genes that can affect how DCIS is likely to behave and respond to treatment. The test is performed on a sample of DCIS tissue. The Oncotype DX DCIS test offers results as a recurrence score. Depending on the recurrence score number, the DCIS has a low, intermediate, or high risk of recurrence. Other factors that should be considered are family history of breast cancer and genetic testing results.
Studies are constantly being conducted and sometimes the results change medical practice. But we can’t see into the future. The best any of us can do is to gather all the information available at the present time and choose what is best for ourselves.