Abstract: Ductal carcinoma in-situ DCIS is a heterogeneous entity in breast neoplasm with unpredictable biological behavior. This poses challenge in the management of DCIS. Various trials on DCIS have shown good outcome with integral treatment of adequate surgery, radiotherapy and hormonal therapy. Identification of subgroup of DCIS for radiotherapy and hormonal therapy could improve recurrence rate, contralateral tumours incidence and perhaps overall survival. Various risk score calculations could help to direct radiotherapy and hormonal treatment verses surgery alone and to avoid over treatment. Oncotype DX assay could be a new way of risk calculation to direct types of DCIS treatment. The recent increased use of MRI could increase the detection of DCIS and a more accurate extent of disease estimation. This article is a summary of major literatures and major trials result for DCIS.
The introduction of national mammographic screening programmes and the increasing use of digital mammography and magnetic resonance imaging (MRI) have dramatically changed the clinical presentation of ductal carcinoma in-situ (DCIS). Prior to this, DCIS made up a small proportion of all breast cancers and was only diagnosed in patients presenting with a palpable mass, pathological nipple discharge or occasionally found as an incidental biopsy finding. In contrast, DCIS is now most frequently identified in asymptomatic women as screendetected micro-calcifications [
DCIS is a heterogeneous pathological entity at a molecular level with a variable and unpredictable biological behavior. Although it is considered to be the precursor of the most invasive breast cancers, however not all DCIS will progress to this stage. The overall progression to invasive breast cancer has been reported to range from 14% to 75% [
Screen-detected DCIS accounts for approximately 25% of newly diagnosed breast cancers and seems to be associated with lower rates of local recurrence after treatment compared with symptomatic disease [3,4] and therefore a proportion of these cases may be less clinically relevant [5,6].
Integral to the successful management of DCIS, is surgical excision of the disease with clear margins [
Treated DCIS has an excellent overall prognosis and therefore differences in survival have been difficult to demonstrate even in large trials. Differences in local recurrence (LR) rates have been used as a surrogate marker for survival. RT was shown to reduce LR in early invasive breast-cancer in 1995 [
An analysis of long term data on patients treated for DCIS from the NSABP B-17 and NSABP B-24 trials [
A recent update from the EORTC 10853 randomized trial showed that RT reduced the risk of any LR by 48% (hazard ratio [HR], 0.52; 95% CI, 0.40 to 0.68; P < 0.001). At 15 years, almost one in three non-irradiated women developed a LR after local excision for DCIS and RT reduced this risk by a factor of 2 [
The UK/ANZ DCIS trial assessed the effect of adjuvant treatment with tamoxifen and radiotherapy after BCS for DCIS. After a median follow-up of 12.7 years [
In a population-based cohort study involving 1676 patients with an average follow up of 7.1 years, Sprague et al reported that the 5-year DFS was similar among women treated with ipsilateral mastectomy compared to women treated with BCS and RT, though women receiving BCS without radiation experienced poorer disease free survival DFS. Women treated with tamoxifen in addition to BCS and RT had a similar risk of a second breast event, although the hazard ratio (HR) suggested a potential benefit however the difference was not statistically significant (0.70, 95% CI 0.41 - 1.19) [
It is clear that there is a significant potential benefit overall for patients with DCIS from adjuvant treatments, but given the very good overall prognosis of this condition, patients with a low risk of LR are likely to be those in which adjuvant treatments could be omitted. Tumour size and grade, age, the presence or absence of necrosis and the “comedo” sub-type have been found to be statistically associated with the risk of LR in an independent pathological review of cases from the UKCCCR/ANZ DCIS trial [
The Van Nuys index (VNI) which is derived from the patients’ age, tumor size, surgical margin width, nuclear grade, and the presence/absence of comedo necrosis is used to determine the risk of LR after BCS for DCIS and guide therapeutic decision-making. [
Further research is required to determine the role of new RT regimes, such as accelerated partial breast irradiation and endocrine therapies. Biological profiling and molecular analysis represent an opportunity to improve our understanding of the tumor biology of this condition and rationalize its treatment. Reliable identification of lowrisk lesions could allow treatment to be less radical or safely omitted.