Posted: August 8, 2015

The news today, August 20, 2015, is full of this story: Ductal carcinoma in situ doesn’t cause death and is being overtreated.  Click here to view the abstract. The problem with the story is that the study on which it is based is fatally flawed.  The authors looked at over 100,000 women with Ductal Carcinoma in Situ and concluded that their risk of dying of invasive breast cancer was the same as that of the general population: 3.3% over the next 20 years.  Hence the authors conclude that the disease is being overtreated.  What is wrong with this analysis?  The authors admit that the vast majority of the women whose records were reviewed for this study had undergone either lumpectomy, mastectomy or bilateral mastectomy as treatment for their DCIS.  How does this change their conclusion?  Simply put, treating DCIS works; once you are treated your chances of dying of breast cancer are the same as that of the general population.  Older studies have clearly shown that if you don’t treat DCIS properly a substantial percentage of those women develop invasive cancer and die.  Dr. Stark weighs in, “This paper will do a great disservice to the public in general and the medical community in particular.  The only thing is shows is that the treatment of DCIS works.  This is not news. Two papers published in 2005, from Vanderbilt and Harvard, show that untreated DCIS will morph into invasive cancer a substantial percentage of the time.”