Is It Time to Abandon Surgery for Low-Risk DCIS?
Ductal carcinoma in situ (DCIS) is considered a nonobligate precursor of invasive breast cancer. Surgery is thought to reduce this risk, as evidenced by studies demonstrating cause-specific survival of 97% to 98% after treatment with mastectomy or lumpectomy with or without radiotherapy. Invasive cancer is found at surgical excision in 26% of all women diagnosed with DCIS by core biopsy and in 20% of those with low- to intermediate-grade DCIS or lesions of 2 cm or smaller on mammography. Despite the apparent success of surgery, significant concerns about overtreatment of DCIS have been raised. The substantial increase in the detection of DCIS between 1992 and 2011 that coincided with the widespread adoption of screening mammography did not result in parallel reductions in invasive cancer detection or breast cancer mortality, suggesting that a proportion of the DCIS being identified would have never progressed to invasive cancer. The very high cause-specific survival after surgery and the limited knowledge of the evolution of untreated DCIS raises the possibility that similar excellent outcomes might be obtained with a less aggressive approach such as active monitoring, with surgery reserved for patients showing evidence of progression to invasive cancer; however, the safety of this approach is uncertain. Ideally, a subset of DCIS patients at low risk of progression to invasive cancer could be identified by molecular profiling, but at present, this goal remains aspirational.
Ductal carcinoma in situ (DCIS) is considered a nonobligate precursor of invasive breast cancer. Surgery is thought to reduce this risk, as evidenced by studies demonstrating cause-specific survival of 97% to 98% after treatment with mastectomy or lumpectomy with or without radiotherapy. Invasive cancer is found at surgical excision in 26% of all women diagnosed with DCIS by core biopsy and in 20% of those with low- to intermediate-grade DCIS or lesions of 2 cm or smaller on mammography. Despite the apparent success of surgery, significant concerns about overtreatment of DCIS have been raised. The substantial increase in the detection of DCIS between 1992 and 2011 that coincided with the widespread adoption of screening mammography did not result in parallel reductions in invasive cancer detection or breast cancer mortality, suggesting that a proportion of the DCIS being identified would have never progressed to invasive cancer. The very high cause-specific survival after surgery and the limited knowledge of the evolution of untreated DCIS raises the possibility that similar excellent outcomes might be obtained with a less aggressive approach such as active monitoring, with surgery reserved for patients showing evidence of progression to invasive cancer; however, the safety of this approach is uncertain. Ideally, a subset of DCIS patients at low risk of progression to invasive cancer could be identified by molecular profiling, but at present, this goal remains aspirational.
