August 22, 2015


Decades of Data Fail to Resolve Debate on Treating Tiny Breast Lesions (GINA KOLATA, AUG. 21, 2015, NY Times)

In an era when there has been so much study of how to treat more advanced cancer, it might seem odd that there is so much uncertainty about these minute sprinklings of abnormal cells, often called Stage 0 cancer, which some say are not cancers at all.

The latest round of controversy was set off by a paper published Thursday in JAMA Oncology that analyzed 20 years of data on 100,000 women who had the condition, which is also known as ductal carcinoma in situ, or D.C.I.S. The majority had lumpectomies (with or without radiation) and most of the others had mastectomies. The death rate from breast cancer of these patients, regardless of their choice of treatment, over the next 20 years was about the same as the lifetime risk in the general population of women, 3.3 percent.

The study's authors and other leading researchers in the field said the data indicates that treatment has not made much of a difference, if any, for the tens of thousands women a year who are told they have this condition. (Last year about 60,000 in the United States got a D.C.I.S. diagnosis.) One piece of evidence is that the women who had mastectomies had their entire breast cut off and so if D.C.I.S. was, as many had thought, a precursor to cancer or an early cancer, their death rate should have been lower than it was for women who had lumpectomies that could have left D.C.I.S. cells behind.

Another major clue is that though tens of thousands of cases of D.C.I.S. were being diagnosed and aggressively treated each year, there seemed to be no substantial impact on the incidence of invasive breast cancers found annually in the general population. About 240,000 were diagnosed with it last year. If treating D.C.I.S. was supposed to fend off invasive breast cancer, the incidence of invasive breast cancer should have plummeted once D.C.I.S. was being found and treated, the experts said.

That has intensified questions about what D.C.I.S. really is -- cancer, precancer, a risk factor for cancer?

Before mammography, only a few hundred women a year were diagnosed with D.C.I.S. It was a condition almost always noticed only on autopsies. 

Another cancer you die with, not from.
Posted by at August 22, 2015 7:39 AM

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