The recent New York Times article questioning the term “cancer” for certain abnormalities detected on mammograms is thought-provoking. The public is not alone in being confused as to what is cancer and what is not. As oncologists, we often ask ourselves if we would seek treatment if ductal carcinoma in situ was identified in our breast. The problem, as Dr. Norton pointed out, is that we don’t always know for certain which cases of DCIS will turn into an aggressive cancer and which will not. Until we are able to identify these cases, oncologists largely recommend treatment with surgery and radiation, to ensure the best outcome for patients (e.g. better to be safe then sorry).
I disagree with Dr. Esserman’s statement that DCIS is not cancer and would point out that a surgeon/radiologist should not be making that call. The point is that DCIS can become cancer. Points to consider:
– DCIS identified on a mammogram and biopsy will be found to have a component of invasive cancer in approximately 10-20% of patients who undergo surgical resection.
– A large randomized trial NSABP 17, with over 800 women, showed that in patients who underwent surgical excision of DCIS, 32% had a recurrence. That is one-third of the women in the study! 17% had invasive cancer come back (not DCIS).
– NSABP 17 results were combined with another trial NSABP 24 looking at the role of Tamoxifen in DCIS. The long term results were published in 2011 and showed that with just surgery alone, 19% of women had a recurrence. This drops to less then 10% recurrence rate when women also had breast radiation and down to 8.5% with the addition of Tamoxifen.
Women with DCIS should meet with both a breast surgeon and radiation oncologist to discuss appropriate treatment. We have made progress in identifying cases of DCIS at high risk of progressing (looking at the cells under the microscope to examine certain features) and can discuss these with each woman and help her make an informed decision.