Saturday, August 22, 2015

Treatment of Ductile Carcinoma in situ

Ductile carcinoma in situ (DCIS), also called stage 0 breast cancer, is diagnosed in about 60,000 women every year.  As the name implies, DCIS consists of abnormal cells located in the milk ducts.  In situ - "in its original place" - means that it has not metastasized. Indeed, DCIS may never metastasize.   But cancer is a scary word, and so the natural tendency is to treat all cancers aggressively, just to be on the safe side.  As a result, tens of thousands women who are diagnosed with DCIS each year are choosing to undergo treatments ranging from lumpectomies followed by chemotherapy, to bilateral breast removals.

A study published this month in JAMA oncology suggests that aggressive treatment of DCIS may not be necessary.  The authors of the study examined the medical records of over 100,000 women who had been diagnosed with DCIS.  They found that women who had been diagnosed with DCIS had about the same risk of death from breast cancer in the next 20 years as women in the general population.  In addition, they found that treatment of DCIS with either lumpectomy/chemotherapy or breast removal (mastectomy) did not alter the subsequent death rate from breast cancer.   In other words, treatment of DCIS did not appear to improve the women's survival rate, compared to the general population of women.

The JAMA oncology study is based solely on an examination of medical records, and while it raises an interesting question (Does DCIS need to be treated?), it does not answer it convincingly.  What is needed now is a carefully controlled study in which women diagnosed with DCIS are randomly assigned to either treatment (lumpectomy/chemotherapy or mastectomy) groups or to a control group, and then followed for the rest of their lives.  Such a study would be expensive and take decades.  In the meantime, the choice of how aggressively to treat DCIS, if at all, will continue to rest with the woman diagnosed with DCIS and her physician.

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