Paradigm Shift toward Reducing Overtreatment of Ductal Carcinoma In Situ of Breast

Abstract

The prevalence of ductal carcinoma in situ (DCIS) of the breast has increased substantially after the introduction of breast cancer screening programs, although the clinical effects of early DCIS detection and treatment remain unclear. The standard treatment for DCIS has involved local breast-conserving surgery (BCS) followed by radiotherapy (RT) or total mastectomy with/without endocrine therapy, and the choice of local treatment is not usually based on clinicopathologic or biological factors. However, we have investigated the effectiveness of local treatment using breast surgery and RT using Surveillance, Epidemiology, and End Results data, and found that the effectiveness of breast surgery was modified by the nuclear grade. Furthermore, breast cancer-specific survival was identical between patients with low-grade DCIS who did and did not undergo surgery. Moreover, we found that RT after BCS for DCIS was only associated with a survival benefit among patients with risk factors for local recurrence, such as nuclear grade, age, and tumor size. Ongoing clinical trials and translational research have attempted to develop a treatment strategy that prevents the overdiagnosis and overtreatment of low-risk DCIS, as well as a biology-based treatment strategy for using targeted therapy. Therefore, to develop a tailored treatment strategy for DCIS, we need to identify molecular and biological classifications based on the results from translational research, national databases, and clinical trials.

Diretrizes para detecção precoce do câncer de mama no Brasil. II - Novas recomendações nacionais, principais evidências e controvérsias

“…Although adjuvant therapy is not risk-free, it seems contradictory that diagnosis of DCIS is associated with an increase in bilateral mastectomies, when one of the arguments generally used to defend mammographic screening is the possibility of performing more conservative surgeries. In the future, the results of clinical trials on the treatment of DCIS and the development of new tests to better stratify the risk of these cases may contribute to decrease the overtreatment of these cases 61 .…”

Galactography is not an obsolete investigation in the evaluation of pathological nipple discharge

“…In this study we had only one associated finding of low grade DCIS in an otherwise normally interpreted galactogram. It might be speculated that this incidental finding is unlikely to develop into a life-threatening disease [ 27 ], and it is therefore reasonable simply to follow-up patients with PND whenever CBE, mammography, ultrasound and galactography are all negative. However, breast MRI was reported to be superior to mammography and US in the detection of both malignant and high risk lesions [ 28 ], and therefore it can be speculated that it can be used routinely to rule out significant causes of PND after negative conventional imaging.…”

Contrasting DCIS and invasive breast cancer by subtype suggests basal-like DCIS as distinct lesions

“…Clinical, histopathological and molecular characteristics may also vary considerabely 10,11 . As a consequence of this uncertainty, treatment for DCIS is often extensive, resulting in substantial overtreatment [12][13][14][15] .…”