On 2017 Aug 28, Daniel Corcos commented:

Haymart et al. recommend active surveillance by mammography for ductal carcinoma in situ (DCIS) of the breast, on the basis that it is a low-risk cancer. Actually, DCIS is at low-risk because it is removed soon after diagnosis, so there is no direct evidence for an intrinsic low malignant potential of this form of early breast cancer. The idea that breast cancer is overdiagnosed rests on the observation of an excess of breast cancers concomitant to mammography screening implementation, which is persistent over years. However, mammography-induced cancers better explain this excess, as they occur with a delay and in older women, like the excess cancers that are observed. Delayed surgery has a dramatic effect on breast cancer survival (1). Active surveillance of DCIS would worsen the prognosis of this otherwise low-risk cancer.

1) Bleicher RJ, Ruth K, Sigurdson ER, et al. Time to Surgery and Breast Cancer Survival in the United States. JAMA Oncol 2016;2:330-9.

On 2017 Aug 28, Daniel Corcos commented:

Haymart et al. recommend active surveillance by mammography for ductal carcinoma in situ (DCIS) of the breast, on the basis that it is a low-risk cancer. Actually, DCIS is at low-risk because it is removed soon after diagnosis, so there is no direct evidence for an intrinsic low malignant potential of this form of early breast cancer. The idea that breast cancer is overdiagnosed rests on the observation of an excess of breast cancers concomitant to mammography screening implementation, which is persistent over years. However, mammography-induced cancers better explain this excess, as they occur with a delay and in older women, like the excess cancers that are observed. Delayed surgery has a dramatic effect on breast cancer survival (1). Active surveillance of DCIS would worsen the prognosis of this otherwise low-risk cancer.

1) Bleicher RJ, Ruth K, Sigurdson ER, et al. Time to Surgery and Breast Cancer Survival in the United States. JAMA Oncol 2016;2:330-9.