Refined estimates of local recurrence risks by DCIS score adjusting for clinicopathological features: a combined analysis of ECOG-ACRIN E5194 and Ontario DCIS cohort studies

Molecular Expression Assays Improve the Prediction of Local and Invasive Local Recurrence After Breast-Conserving Surgery for Ductal Carcinoma In Situ

PURPOSE

Ductal carcinoma in situ (DCIS) is routinely treated with adjuvant radiotherapy (RT) after breast-conserving surgery (BCS). The inability to accurately estimate an individual's risk of local recurrence (LR) and invasive LR using clinicopathologic factors (CPF) contributes to the overtreatment of DCIS. We examined the impact of the 12-gene DCIS Score (DS) and the 21-gene Recurrence Score (RS) on the accuracy of predicting LR and invasive LR.

METHODS

A population-based cohort diagnosed with pure DCIS treated with BCS ± RT from 1994 to 2003 was used. All patients had expert pathology review and assessment of the DS and RS. Predictive models (CPF alone, DS + CPF, and RS + CPF) were developed using multivariable Cox regression analyses to predict 10-year LR and invasive LR risks. Models were evaluated on the basis of c-statistic, -2log likelihood estimate (-2LLE), and Akaike information criterion. Calibration was performed using bootstrap resamples, with replacement.

RESULTS

The cohort includes 1,226 women treated with BCS; 712 received RT. 194 women (15.8%) experienced ipsilateral LR as a first event; 112 were invasive. Models including the DS or RS performed better in predicting the 10-year risk of LR compared with models on the basis of CPF alone with excellent calibration. The two molecular-based models also performed better in predicting invasive LR compared with the CPF model but the model incorporating the RS did not perform better in the prediction of invasive LR compared with the DS-based model.

CONCLUSION

Models incorporating the DS or RS more accurately predicted the 10-year risk of LR and invasive LR after BCS compared with models on the basis of CPF alone. Inclusion of the RS, compared with DS, did not improve the prediction of the 10-year risk of invasive LR.

Tools to Guide Radiation Oncologists in the Management of DCIS

Similar to invasive breast cancer, ductal carcinoma in situ is also going through a phase of changes not only from a technical but also a conceptual standpoint. From prescribing radiotherapy to everyone to personalized approaches, including radiotherapy omission, there is still a lack of a comprehensive framework to guide radiation oncologists in decision making. Many pieces of the puzzle are finding their place as high-quality data mature and are disseminated, but very often, the interpretation of risk factors and the perception of risk remain very highly subjective. Sharing the therapeutic choice with patients requires effective communication for an understanding of risks and benefits, facilitating an informed decision that does not increase anxiety and concerns about prognosis. The purpose of this narrative review is to summarize the current state of knowledge to highlight the tools available to radiation oncologists for managing DCIS, with an outlook on future developments.

Progression from ductal carcinoma in situ to invasive breast cancer: molecular features and clinical significance

Ductal carcinoma in situ (DCIS) represents pre-invasive breast carcinoma. In untreated cases, 25-60% DCIS progress to invasive ductal carcinoma (IDC). The challenge lies in distinguishing between non-progressive and progressive DCIS, often resulting in over- or under-treatment in many cases. With increasing screen-detected DCIS in these years, the nature of DCIS has aroused worldwide attention. A deeper understanding of the biological nature of DCIS and the molecular journey of the DCIS-IDC transition is crucial for more effective clinical management. Here, we reviewed the key signaling pathways in breast cancer that may contribute to DCIS initiation and progression. We also explored the molecular features of DCIS and IDC, shedding light on the progression of DCIS through both inherent changes within tumor cells and alterations in the tumor microenvironment. In addition, valuable research tools utilized in studying DCIS including preclinical models and newer advanced technologies such as single-cell sequencing, spatial transcriptomics and artificial intelligence, have been systematically summarized. Further, we thoroughly discussed the clinical advancements in DCIS and IDC, including prognostic biomarkers and clinical managements, with the aim of facilitating more personalized treatment strategies in the future. Research on DCIS has already yielded significant insights into breast carcinogenesis and will continue to pave the way for practical clinical applications.

Duration of Endocrine Treatment for DCIS impacts second events: Insights from a large cohort of cases at two academic medical centers

Ductal carcinoma in situ (DCIS) incidence has risen rapidly with the introduction of screening mammography, yet it is unclear who benefits from both the amount and type of adjuvant treatment (radiation therapy, (RT), endocrine therapy (ET)) versus what constitutes over-treatment. Our goal was to identify the effects of adjuvant RT, or ET+/- RT versus breast conservation surgery (BCS) alone in a large multi-center registry of retrospective DCIS cases (N = 1,916) with median follow up of 8.2 years. We show that patients with DCIS who took less than 2 years of adjuvant ET alone have a similar second event rate as BCS. However, patients who took more than 2 years of ET show a significantly reduced second event rate, similar to those who received either RT or combined ET+RT, which was independent of age, tumor size, grade, or period of diagnosis. This highlights the importance of ET duration for risk reduction.

Artificial intelligence-based morphometric signature to identify ductal carcinoma in situ with low risk of progression to invasive breast cancer

Ductal carcinoma in situ (DCIS) may progress to ipsilateral invasive breast cancer (iIBC), but often never will. Because DCIS is treated as early breast cancer, many women with harmless DCIS face overtreatment. To identify these women that may forego treatment, we hypothesized that DCIS morphometric features relate to the risk of subsequent iIBC. We developed an artificial intelligence-based DCIS morphometric analysis pipeline (AIDmap) to detect DCIS as a pathologist and measure morphological structures in hematoxylin-eosin-stained (H&E) tissue sections. These were from a case-control study of patients diagnosed with primary DCIS, treated by breast-conserving surgery without radiotherapy. We analyzed 689 WSIs of DCIS of which 226 were diagnosed with subsequent iIBC (cases) and 463 were not (controls). The distribution of 15 duct morphological measurements in each H&E was summarized in 55 morphometric variables. A ridge regression classifier with cross validation predicted 5-years-free of iIBC with an area-under the curve of 0.65 (95% CI 0.55-0.76). A morphometric signature based on the 30 variables most associated with outcome, identified lesions containing small-sized ducts, low number of cells and low DCIS/stroma area ratio. This signature was associated with lower iIBC risk in a multivariate regression model including grade, ER, HER2 and COX-2 expression (HR = 0.56; 95% CI 0.28-0.78). AIDmap has potential to identify harmless DCIS that may not need treatment.

Outcome of different radiotherapy strategies after breast conserving surgery in patients with ductal carcinoma in situ (DCIS)

BACKGROUND

Adjuvant radiotherapy (RT) after breast-conserving surgery for DCIS lowers the relative local recurrence risk by half. To identify a low-risk group with the minimal benefit of RT could avoid side effects and spare costs. In this study, the outcome was compared for different RT-strategies using data from the randomized SweDCIS trial.

MATERIAL AND METHODS

Five strategies were compared in a Swedish setting: RT-to-none or all, RT to high-risk women defined by DCISionRT, modified Radiation Therapy Oncology Group (RTOG) 9804 criteria, and Swedish Guidelines. Ten-year recurrence risks and cost including adjuvant RT and local recurrence treatment cost were calculated.

RESULTS

The mean age at recurrence was 64.4 years (36-90) and the mean cost for treating a recurrence was $21,104. In the SweDCIS cohort (n = 504), 59 women developed DCIS, and 31 invasive recurrence. Ten-year absolute local recurrence risk (invasive and DCIS) according to different strategies varied between 18.6% (12.5-23.6%) and 7.8% (5.0-12.6%) for RT-to-none or to-all, with an additional cost of $2614 US dollars per women and $24,201 per prevented recurrence for RT-to-all. The risk differences between other strategies were not statistically significant, but the larger proportion receiving RT, the fewer recurrences. DCISionRT spared 48% from RT with 8.1% less recurrences compared to RT-to-none, and a cost of $10,534 per prevented recurrence with additional cost depending on the price of the test. RTOG 9804 spared 39% from RT, with 9.7% less recurrences, $9525 per prevented recurrence and Swedish Guidelines spared 13% from RT, with 10.0% less recurrences, and $21,521 per prevented recurrence.

CONCLUSION

It seems reasonable to omit RT in pre-specified low-risk groups with minimal effect on recurrence risk. Costs per prevented recurrence varied more than two-fold but which strategy that could be considered most cost-effective needs to be further evaluated, including the DCISionRT-test price.

Can Molecular Biomarkers Help Reduce the Overtreatment of DCIS?

Ductal carcinoma in situ (DCIS), especially in the era of mammographic screening, is a commonly diagnosed breast tumor. Despite the low breast cancer mortality risk, management with breast conserving surgery (BCS) and radiotherapy (RT) is the prevailing treatment approach in order to reduce the risk of local recurrence (LR), including invasive LR, which carries a subsequent risk of breast cancer mortality. However, reliable and accurate individual risk prediction remains elusive and RT continues to be standardly recommended for most women with DCIS. Three molecular biomarkers have been studied to better estimate LR risk after BCS-Oncotype DX DCIS score, DCISionRT Decision Score and its associated Residual Risk subtypes, and Oncotype 21-gene Recurrence Score. All these molecular biomarkers represent important efforts towards improving predicted risk of LR after BCS. To prove clinical utility, these biomarkers require careful predictive modeling with calibration and external validation, and evidence of benefit to patients; on this front, further research is needed. Most trials do not incorporate molecular biomarkers in evaluating de-escalation of therapy for DCIS; however, one-the Prospective Evaluation of Breast-Conserving Surgery Alone in Low-Risk DCIS (ELISA) trial-incorporates the Oncotype DX DCIS score in defining a low-risk population and is an important next step in this line of research.

The Landmark Series-Ductal Carcinoma in Situ: The Evolution of Treatment

The evolution of ductal carcinoma in situ (DCIS) management has been driven by a parallel evolution in our understanding of its natural history. Early trials established the benefit of adjuvant therapies in all patients with DCIS. In contrast, subsequent studies have stratified patients to determine their eligibility for progressively less invasive and less intensive therapies. Large, randomized trials and meta-analyses have supported this shift away from treating DCIS as an homogenous disease treated with similar intensity to invasive breast cancer. This review describes the landmark studies on which current DCIS management is based.

Predicting Breast Cancer Events in Ductal Carcinoma In Situ (DCIS) Using Generative Adversarial Network Augmented Deep Learning Model

Standard clinicopathological parameters (age, growth pattern, tumor size, margin status, and grade) have been shown to have limited value in predicting recurrence in ductal carcinoma in situ (DCIS) patients. Early and accurate recurrence prediction would facilitate a more aggressive treatment policy for high-risk patients (mastectomy or adjuvant radiation therapy), and simultaneously reduce over-treatment of low-risk patients. Generative adversarial networks (GAN) are a class of DL models in which two adversarial neural networks, generator and discriminator, compete with each other to generate high quality images. In this work, we have developed a deep learning (DL) classification network that predicts breast cancer events (BCEs) in DCIS patients using hematoxylin and eosin (H & E) images. The DL classification model was trained on 67 patients using image patches from the actual DCIS cores and GAN generated image patches to predict breast cancer events (BCEs). The hold-out validation dataset (n = 66) had an AUC of 0.82. Bayesian analysis further confirmed the independence of the model from classical clinicopathological parameters. DL models of H & E images may be used as a risk stratification strategy for DCIS patients to personalize therapy.

Molecular Signatures in Ductal Carcinoma In Situ (DCIS): A Systematic Review and Meta-Analysis

CONTEXT

Adjuvant radiotherapy (RT) after breast-conserving surgery (BCS) for ductal carcinoma in situ (DCIS) is debated as benefits are inconstant. Molecular signatures for DCIS have been developed to stratify the risk of local recurrence (LR) and therefore guide the decision of RT.

OBJECTIVE

To evaluate, in women with DCIS treated by BCS, the impact of adjuvant RT on LR according to the molecular signature risk stratification.

METHODOLOGY

We conducted a systematic review and meta-analysis of five articles including women with DCIS treated by BCS and with a molecular assay performed to stratify the risk, comparing the effect of BCS and RT versus BCS alone on LR including ipsilateral invasive (InvBE) and total breast events (TotBE).

RESULTS

The meta-analysis included 3478 women and evaluated two molecular signatures: Oncotype Dx DCIS (prognostic of LR), and DCISionRT (prognostic of LR and predictive of RT benefit). For DCISionRT, in the high-risk group, the pooled hazard ratio of BCS + RT versus BCS was 0.39 (95%CI 0.20-0.77) for InvBE and 0.34 (95%CI 0.22-0.52) for TotBE. In the low-risk group, the pooled hazard ratio of BCS + RT versus BCS was significant for TotBE at 0.62 (95%CI 0.39-0.99); however, it was not significant for InvBE (HR = 0.58 (95%CI 0.25-1.32)), Discussion: Molecular signatures are able to discriminate high- and low-risk women, high-risk ones having a significant benefit of RT in the reduction of invasive and in situ local recurrences, while in low-risk ones RT did not have a benefit for preventing invasive breast recurrence. The risk prediction of molecular signatures is independent of other risk stratification tools developed in DCIS, and have a tendency toward RT de-escalation. Further studies are needed to assess the impact on mortality.

De-Escalating the Management of In Situ and Invasive Breast Cancer

Simple Summary

De-escalation of breast cancer treatment reduces morbidity and toxicity for patients. De-escalation is safe if cancer outcomes, such as recurrence and survival, remain unaffected compared to more radical regimens. This review provides an overview on treatment de-escalation for ductal carcinoma in situ (DCIS), local treatment of breast cancer, and surgery after neoadjuvant systemic therapy. Improvements in understanding the natural history and biology of breast cancer, imaging modalities, and adjuvant treatments have facilitated de-escalation of treatment over time.

Abstract

It is necessary to identify appropriate areas of de-escalation in breast cancer treatment to minimize morbidity and maximize patients’ quality of life. Less radical treatment modalities, or even no treatment, have been reconsidered if they offer the same oncologic outcomes as standard therapies. Identifying which patients benefit from de-escalation requires particular care, as standard therapies will continue to offer adequate cancer outcomes. We provide an overview of the literature on the de-escalation of treatment of ductal carcinoma in situ (DCIS), local treatment of breast cancer, and surgery after neoadjuvant systemic therapy. De-escalation of breast cancer treatment is a key area of investigation that will continue to remain a priority. Improvements in understanding the natural history and biology of breast cancer, imaging modalities, and adjuvant treatments will expand this even further. Future efforts will continue to challenge us to consider the true role of various treatment modalities.

MiRNA expression deregulation correlates with the Oncotype DX® DCIS score

Background

Current clinical criteria do not discriminate well between women who will or those who will not develop ipsilateral invasive breast cancer (IBC), or a DCIS recurrence after a ductal carcinoma in situ (DCIS) diagnosis. The 12-gene Oncotype DX® DCIS assay (RT qPCR gene-based scoring system) was established and shown to predict the risk of subsequent ipsilateral IBC or DCIS recurrence. Recent studies have shown that microRNA (miRNA) expression deregulation can contribute to the development of IBC, but very few have evaluated miRNA deregulation in DCIS lesions. In this study, we sought to determine whether specific miRNA expression changes may correlate with Oncotype DX® DCIS scores.

Methods

For this study, we used archived formalin-fixed, paraffin-embedded (FFPE) specimens from 41 women diagnosed with DCIS between 2012 and 2018. The DCIS lesions were stratified into low (n = 26), intermediate (n = 10), and high (n = 5) risk score groups using the Oncotype DX® DCIS assay. Total RNA was extracted from DCIS lesions by macro-dissection of unstained FFPE sections, and next-generation small-RNA sequencing was performed. We evaluated the correlation between miRNA expression data and Oncotype score, as well as patient age. RT-qPCR validations were performed to validate the topmost differentially expressed miRNAs identified between the different risk score groups.

Results

MiRNA sequencing of 32 FFPE DCIS specimens from the three different risk group scores identified a correlation between expression deregulation of 17 miRNAs and Oncotype scores. Our analyses also revealed a correlation between the expression deregulation of 9 miRNAs and the patient’s age. Based on these results, a total of 15 miRNAs were selected for RT-qPCR validation. Of these, miR-190b (p = 0.043), miR-135a (p = 0.05), miR-205 (p = 0.00056), miR-30c (p = 0.011), and miR-744 (p = 0.038) showed a decreased expression in the intermediate/high Oncotype group when compared to the low-risk score group. A composite risk score was established using these 5 miRNAs and indicated a significant association between miRNA expression deregulation and the Oncotype DX® DCIS Score (p < 0.0021), between high/intermediate and low risk groups.

Conclusions

Our analyses identified a subset of 5 miRNAs able to discriminate between Oncotype DX® DCIS score subgroups. Together, our data suggest that miRNA expression analysis may add value to the predictive and prognostic evaluation of DCIS lesions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-022-01558-4.

Prediction Models and Decision Aids for Women with Ductal Carcinoma In Situ: A Systematic Literature Review

Simple Summary

Ductal carcinoma in situ (DCIS) is a potential precursor to invasive breast cancer (IBC). Although in many women DCIS will never become breast cancer, almost all women diagnosed with DCIS undergo surgery with/without radiotherapy. Several studies are ongoing to de-escalate treatment for DCIS. Multiple decision support tools have been developed to aid women with DCIS in selecting the best treatment option for their specific goals. The aim of this study was to identify these decision support tools and evaluate their quality and clinical utility. Thirty-three studies were reviewed, in which four decision aids and six prediction models were described. While some of these models might be promising, most lacked important qualities such as tools to help women discuss their options or good quality validation studies. Therefore, the need for good quality, well validated decision support tools remains unmet.

Abstract

Even though Ductal Carcinoma in Situ (DCIS) can potentially be an invasive breast cancer (IBC) precursor, most DCIS lesions never will progress to IBC if left untreated. Because we cannot predict yet which DCIS lesions will and which will not progress, almost all women with DCIS are treated by breast-conserving surgery +/− radiotherapy, or even mastectomy. As a consequence, many women with non-progressive DCIS carry the burden of intensive treatment without any benefit. Multiple decision support tools have been developed to optimize DCIS management, aiming to find the balance between over- and undertreatment. In this systematic review, we evaluated the quality and added value of such tools. A systematic literature search was performed in Medline(ovid), Embase(ovid), Scopus and TRIP. Following the PRISMA guidelines, publications were selected. The CHARMS (prediction models) or IPDAS (decision aids) checklist were used to evaluate the tools’ methodological quality. Thirty-three publications describing four decision aids and six prediction models were included. The decision aids met at least 50% of the IPDAS criteria. However, most lacked tools to facilitate discussion of the information with healthcare providers. Five prediction models quantify the risk of an ipsilateral breast event after a primary DCIS, one estimates the risk of contralateral breast cancer, and none included active surveillance. Good quality and external validations were lacking for all prediction models. There remains an unmet clinical need for well-validated, good-quality DCIS risk prediction models and decision aids in which active surveillance is included as a management option for low-risk DCIS.

Overdetection of Breast Cancer

Overdetection (often referred to as overdiagnosis) of cancer is the detection of disease, such as through a screening program, that would otherwise remain occult through an individual’s life. In the context of screening, this could occur for cancers that were slow growing or indolent, or simply because an unscreened individual would have died from some other cause before the cancer had surfaced clinically. The main harm associated with overdetection is the subsequent overdiagnosis and overtreatment of disease. In this article, the phenomenon is reviewed, the methods of estimation of overdetection are discussed and reasons for variability in such estimates are given, with emphasis on an analysis using Canadian data. Microsimulation modeling is used to illustrate the expected time course of cancer detection that gives rise to overdetection. While overdetection exists, the actual amount is likely to be much lower than the estimate used by the Canadian Task Force on Preventive Health Care. Furthermore, the issue is of greater significance in older rather than younger women due to competing causes of death. The particular challenge associated with in situ breast cancer is considered and possible approaches to avoiding overtreatment are suggested.

Atypical Ductal Hyperplasia-Ductal Carcinoma In Situ Spectrum: Diagnostic Considerations and Treatment Impact in the Era of Deescalation

As the first node in treatment algorithms for breast disease, pathologists have the potential to play a critical role in refining appropriate therapy for lesions in the atypical ducal hyperplasia-ductal carcinoma in situ (ADH-DCIS) spectrum by conservatively approaching diagnosis of lesions limited in size on core needle biopsy. Appropriate efforts to downgrade the diagnosis of lesions at the borderline of ADH and DCIS will certainly lead to more breast conservation and avoid the common morbidities of mastectomy, sentinel node biopsy, and radiation therapy. Whether results of clinical trials of active surveillance will successfully identify a subset of women who may successfully forgo even limited breast-conserving surgery is eagerly anticipated. Given the increasing concern that a significant number of women with DCIS are overtreated, identification of patients at very low risk for progression who may forgo surgery and radiation therapy safely is of significant interest.

Updates on treating ductal carcinoma in situ: what's to know in 2021

PURPOSE OF REVIEW

Ductal carcinoma in situ (DCIS) is a noninvasive stage of disease but understood to be a nonobligate precursor to invasive breast cancer. As such, women with DCIS are routinely recommended for standard breast cancer treatment to prevent progression to invasive disease. DCIS, however, represents a heterogeneous group of lesions that differs in its biologic behavior and risk of progression. Thus, optimal treatment is unclear. This review presents the clinical trials evaluating the de-escalation of therapy, attempts at risk stratification, and future directions in the management of this disease.

RECENT FINDINGS

The de-escalation of therapy for patients with DCIS is being actively explored. Although no group of patients based on clinicopathologic features has yet been identified as suitable for omission of therapy, molecular tests appear better able to stratify patients at low risk for whom omission of radiation may be considered. Trials considering omission of surgery are ongoing, and the use of Herceptin and vaccine therapy are also being explored.

SUMMARY

The current review provides a centralized summary enabling the clinician to better understand the complexity of DCIS and the controversies over the optimal management of this disease. It highlights the need for better risk stratification to individualize patient care.

VIDEO ABSTRACT

http://links.lww.com/COOG/A77.

Preneoplastic Low-Risk Mammary Ductal Lesions (Atypical Ductal Hyperplasia and Ductal Carcinoma In Situ Spectrum): Current Status and Future Directions

Intraepithelial mammary ductal neoplasia is a spectrum of disease that varies from atypical ductal hyperplasia (ADH), low-grade (LG), intermediate-grade (IG), to high-grade (HG) ductal carcinoma in situ (DCIS). While ADH has the lowest prognostic significance, HG-DCIS carries the highest risk. Due to widely used screening mammography, the number of intraepithelial mammary ductal neoplastic lesions has increased. The consequence of this practice is the increase in the number of patients who are overdiagnosed and, therefore, overtreated. The active surveillance (AS) trials are initiated to separate lesions that require active treatment from those that can be safely monitored and only be treated when they develop a change in the clinical/radiologic characteristics. At the same time, the natural history of these lesions can be evaluated. This review aims to evaluate ADH/DCIS as a spectrum of intraductal neoplastic disease (risk and histomorphology); examine the controversies of distinguishing ADH vs. DCIS and the grading of DCIS; review the upgrading for both ADH and DCIS with emphasis on the variation of methods of detection and the definitions of upgrading; and evaluate the impact of all these variables on the AS trials.

Randomized Phase III Trial Evaluating Radiation Following Surgical Excision for Good-Risk Ductal Carcinoma In Situ: Long-Term Report From NRG Oncology/RTOG 9804

PURPOSE

To our knowledge, NRG/RTOG 9804 is the only randomized trial to assess the impact of whole breast irradiation (radiation therapy [RT]) versus observation (OBS) in women with good-risk ductal carcinoma in situ (DCIS), following lumpectomy. Long-term results focusing on ipsilateral breast recurrence (IBR), the primary outcome, are presented here.

PATIENTS AND METHODS

Eligible patients underwent lumpectomy for DCIS that was mammogram detected, size ≤ 2.5 cm, final margins ≥ 3 mm, and low or intermediate nuclear grade. Consented patients were randomly assigned to RT or OBS. Tamoxifen use was optional. Cumulative incidence was used to estimate IBR, log-rank test and Gray's test to compare treatments, and Fine-Gray regression for hazard ratios (HRs).

RESULTS

A total of six hundred thirty-six women were randomly assigned from 1999 to 2006. Median age was 58 years and mean pathologic DCIS size was 0.60 cm. Intention to use tamoxifen was balanced between arms (69%); however, actual receipt of tamoxifen varied, 58% RT versus 66% OBS (P = .05). At 13.9 years' median follow-up, the 15-year cumulative incidence of IBR was 7.1% (95% CI, 4.0 to 11.5) with RT versus 15.1% (95% CI, 10.8 to 20.2) OBS (P = .0007; HR = 0.36; 95% CI, 0.20 to 0.66); and for invasive LR was 5.4% (95% CI, 2.7 to 9.5) RT versus 9.5% (95% CI, 6.0 to 13.9) OBS (P = .027; HR = 0.44; 95% CI, 0.21 to 0.91). On multivariable analysis, only RT (HR = 0.34; 95% CI, 0.19 to 0.64; P = .0007) and tamoxifen use (HR = 0.45; 95% CI, 0.25 to 0.78; P = .0047) were associated with reduced IBR.

CONCLUSION

RT significantly reduced all and invasive IBR for good-risk DCIS with durable results at 15 years. These results are not an absolute indication for RT but rather should inform shared patient-physician treatment decisions about ipsilateral breast risk reduction in the long term following lumpectomy.

DUCHESS: an evaluation of the ductal carcinoma in situ score for decisions on radiotherapy in patients with low/intermediate-risk DCIS

BACKGROUND

Identification of women with DCIS who have a very low risk of local recurrence risk (LRR) after breast-conserving surgery (BCS) is needed to de-escalate therapy. We evaluated the impact of 10-year LRR estimates after BCS, calculated by the integration of a 12-gene molecular expression assay (Oncotype Breast DCIS Score^®) and clinicopathological features (CPFs), on its ability to change radiation oncologists' recommendations for RT after BCS for DCIS.

METHODS

Prospective cohort study of women with DCIS treated with BCS. Eligibility criteria were as follows: age > 45 years, tumor ≤ 2.5 cm, and margins ≥ 1 mm. Radiation oncologists provided 10-year LRR estimates without RT and recommendation for RT pre- and post-assay. Primary outcome was change in RT recommendation.

RESULTS

217 patients were evaluable, with mean age = 63 years, mean tumor size = 1.1 cm, and mean DCIS Score = 32; 140 (64%) were in the low-risk (<39), 32 (15%) were in the intermediate-risk (39-54), and 45 (21%) were in the high-risk groups (≥55). The assay led to a change in treatment recommendation in 76 (35.2%) (95%CI 29.1-41.8%) patients. RT recommendations decreased from 79% pre-assay to 50% post-assay (difference = 29%; 95%CI 22-35%) due to a significant increase in the proportion of patients with a predicted low LRR (< 10%) post-assay and recommendations to omit RT for those with a low predicted risk. The assay was associated with improved patient satisfaction and reduced decisional conflict.

CONCLUSION

The DCIS Score assay combined with CPFs identified more women with an estimated low (<10%) 10-yr LR risk after BCS, leading to a significant decrease in recommendations for RT compared to estimates based on CPFs alone.

Breast adipocyte size associates with ipsilateral invasive breast cancer risk after ductal carcinoma in situ

Although ductal carcinoma in situ (DCIS) is a non-obligate precursor to ipsilateral invasive breast cancer (iIBC), most DCIS lesions remain indolent. Hence, overdiagnosis and overtreatment of DCIS is a major concern. There is an urgent need for prognostic markers that can distinguish harmless from potentially hazardous DCIS. We hypothesised that features of the breast adipose tissue may be associated with risk of subsequent iIBC. We performed a case-control study nested in a population-based DCIS cohort, consisting of 2658 women diagnosed with primary DCIS between 1989 and 2005, uniformly treated with breast conserving surgery (BCS) alone. We assessed breast adipose features with digital pathology (HALO®, Indica Labs) and related these to iIBC risk in 108 women that developed subsequent iIBC (cases) and 168 women who did not (controls) by conditional logistic regression, accounting for clinicopathological and immunohistochemistry variables. Large breast adipocyte size was significantly associated with iIBC risk (odds ratio (OR) 2.75, 95% confidence interval (95% CI) = 1.25-6.05). High cyclooxygenase (COX)-2 protein expression in the DCIS cells was also associated with subsequent iIBC (OR 3.70 (95% CI = 1.59-8.64). DCIS with both high COX-2 expression and large breast adipocytes was associated with a 12-fold higher risk (OR 12.0, 95% CI = 3.10-46.3, P < 0.001) for subsequent iIBC compared with women with smaller adipocyte size and low COX-2 expression. Large breast adipocytes combined with high COX-2 expression in DCIS is associated with a high risk of subsequent iIBC. Besides COX-2, adipocyte size has the potential to improve clinical management in patients diagnosed with primary DCIS.

Ductal Carcinoma In Situ and Progression to Invasive Cancer: A Review of the Evidence

Ductal carcinoma in situ (DCIS), breast cancer confined to the milk ducts, is a heterogeneous entity. The question of how and when a case of DCIS will extend beyond the ducts to become invasive breast cancer has implications for both patient prognosis and optimal treatment approaches. The natural history of DCIS has been explored through a variety of methods, from mouse models to biopsy specimen reviews to population-based screening data to modeling studies. This article will review the available evidence regarding progression pathways and will also summarize current trials designed to assess DCIS progression.

[RNA in situ hybridization: technology, potential, and fields of application]

Significant improvements in the technology of RNA in situ hybridization (RNA-ISH) in the past five decades have opened up novel fields of its application as a valuable and an attractive adjunct to the portfolio of pathologist's daily routine diagnostic practice.In contrast to the former methodology, the current bDNA-based technology is not only easier to handle but also considerably more sensitive, enabling single-target molecule detection in formalin-fixed and paraffin-embedded tissue specimens without significant effort by both the lab and the evaluating pathologist, as assays can be run on standard automated staining devices and evaluated by light microscopy. Compared to molecular methods like RT-PCR and whole-genome analysis, RNA-ISH maintains tissue integrity thus offering the invaluable advantage of localization of target cells especially in relation to secreted proteins and expression of the target sequence in multiple cell types. The first clinical trials implementing RNA-ISH for patient stratification and selection are in progress and already led to the first drug approvals based on its use as a CDx test.In addition to its role as a complementary method for the establishment of novel IHC procedures or as an addition or replacement to IHC in the standard routine portfolio, RNA-ISH has gained special importance for its capacity to detect noncoding RNA species or mutation or splice variants, where no alternative procedures are available. This more complex application requires development of standardized procedures and involvement of the pathologist during assay establishment and for routine specimen evaluation.The present article reviews the development of RNA-ISH from its early uses to its current applications in research and diagnostics based on the authors' considerable experience of applying it as tool in a biopharmaceutical research organization.

Patterns of treatment and outcome of ductal carcinoma in situ in the Netherlands

Purpose

To spare DCIS patients from overtreatment, treatment de-escalated over the years. This study evaluates the influence of these developments on the patterns of care in the treatment of DCIS with particular interest in the use of breast conserving surgery (BCS), radiotherapy following BCS and the use and type of axillary staging.

Methods

In this large population-based cohort study all women, aged 50–74 years diagnosed with DCIS from January 1989 until January 2019, were analyzed per two-year cohort.

Results

A total of 30,417 women were diagnosed with DCIS. The proportion of patients undergoing BCS increased from 47.7% in 1995–1996 to 72.7% in 2017–2018 (p < 0.001). Adjuvant radiotherapy following BCS increased from 28.9% (1995–1996) to 89.6% (2011–2012) and subsequently decreased to 74.9% (2017–2018; p < 0.001). Since its introduction, the use of sentinel lymph node biopsy (SLNB) increased to 63.1% in 2013–2014 and subsequently decreased to 52.8% in 2017–2018 (p < 0.001). Axillary surgery is already omitted in 55.8% of the patients undergoing BCS nowadays. The five-year invasive relapse-free survival (iRFS) for BCS with adjuvant radiotherapy in the period 1989–2010, was 98.7% [CI 98.4% – 99.0%], compared to 95.0% [CI 94.1% –95.8%] for BCS only (p < 0.001). In 2011–2018, this was 99.3% [CI 99.1% – 99.5%] and 98.8% [CI 98.2% – 99.4%] respectively (p = 0.01).

Conclusions

This study shows a shift toward less extensive treatment. DCIS is increasingly treated with BCS and less often followed by additional radiotherapy. The absence of radiotherapy still results in excellent iRFS. Axillary surgery is increasingly omitted in DCIS patients.

Diagnosis of ductal carcinoma in situ in an era of de-escalation of therapy

Concerns about overdiagnosis and overtreatment have led to interest in de-escalating treatment for ductal carcinoma in situ (DCIS). This article reviews the epidemiology, natural history, and current treatment options for DCIS and discusses ongoing efforts to further de-escalate treatment for these patients.

21-Gene Assay and Breast Cancer Mortality in Ductal Carcinoma In Situ

BACKGROUND

The inability to identify individuals with ductal carcinoma in situ (DCIS) who are at risk of breast cancer (BC) mortality have hampered efforts to reduce the overtreatment of DCIS. The 21-gene recurrence score (RS) predicts distant metastases for individuals with invasive BC, but its prognostic utility in DCIS is unknown.

METHODS

We performed a population-based analysis of 1362 individuals of DCIS aged 75 years or younger at diagnosis treated with breast-conserving therapy. We examined the association between a high RS (defined a priori as >25) and the risk of BC mortality by using a propensity score-adjusted model accounting for the competing risk of death from other causes, testing for interactions. All statistical tests were 2-sided.

RESULTS

With 16 years median follow-up, 36 (2.6%) died of BC, and 200 (14.7%) died of other causes. The median value of the RS was 15 (range = 0-84); 29.6% of individuals had a high RS. A high RS was associated with an 11-fold increased risk of BC mortality (hazard ratio = 11.27, 95% confidence interval [CI] = 3.00 to 42.33; P < .001) in women aged 50 years or younger at diagnosis treated with breast-conserving surgery alone, culminating in a 9.4% (95% CI = 2.3% to 22.5%) 20-year risk of BC death. For women with a high RS, treatment with radiotherapy was associated with a 71% (hazard ratio = 0.29, 95% CI = 0.10 to 0.89; P = .03) relative and a 5% absolute reduction in the 20-year cumulative risk of death from BC.

CONCLUSION

The 21-gene RS predicts BC mortality in DCIS and combined with age (50 years or younger) at diagnosis can identify individuals for whom radiotherapy reduces the risk of death from BC.

A Comparison of Predicted Ipsilateral Tumor Recurrence Risks in Patients With Ductal Carcinoma in Situ of the Breast After Breast-Conserving Surgery by Breast Radiation Oncologists, the Van Nuys Prognostic Index, the Memorial Sloan Kettering Cancer Center DCIS Nomogram, and the 12-Gene DCIS Score Assay

Purpose

To compare ipsilateral breast event (IBE) risks in patients with ductal carcinoma in situ of the breast (DCIS) post-lumpectomy, as estimated by breast radiation oncologists, the Van Nuys Prognostic Index, the Memorial Sloan Kettering Cancer Center (MSKCC) DCIS nomogram, and the 12-gene Oncotype DX DCIS score assay.

Methods and Materials

Consecutive DCIS cases treated with lumpectomy from November 2011 to August 2014 with available DCIS score results were identified. Three radiation oncologists independently estimated the 10-year IBE risk. The Van Nuys Prognostic Index and MSKCC nomogram 10-year IBE risk estimates were generated. Differences and correlations between the IBE estimates and clinicopathologic factors were evaluated.

Results

Ninety-one patients were identified for inclusion. Forty-eight percent would have been ineligible for the E5194 study. The mean risk of IBE from the DCIS score assay was 12.4%, compared with a range of 18.9% to 26.8% from other sources. The mean IBE risk from the DCIS score assay was lower regardless of E5194 eligibility. The MSKCC nomogram and DCIS score assay risk estimates were weakly correlated with each other (P = .23) and were each moderately correlated with the other risk estimates (P = .41-.56). When applying the radiation oncologists’ treatment recommendations based on their proposed risk cutoffs, evaluating risk according to the DCIS score assay led to the highest proportion of patients recommended excision alone.

Conclusions

IBE risk estimates for this general community cohort of DCIS cases vary significantly among commonly available clinical predictive tools and individual radiation oncologist estimates. Surgical margins and tumor size continue to factor prominently in radiation oncologist decision algorithms. The differences found between the IBE risk estimate methods suggests that they are not interchangeable and the methods that rely on clinicopathologic features may tend to overestimate risk.

Cost-Effectiveness Analysis of Biological Signature DCISionRT Use for DCIS Treatment

BACKGROUND

Currently it remains difficult to identify patients most likely to benefit from radiotherapy (RT) for ductal carcinoma-in-situ (DCIS), thus leading to wide variation in practice patterns. The genomic risk assessment tool DCISionRT (PreludeDX) has been validated to prognosticate recurrence risk and predict RT benefit. We aimed to study the cost-effectiveness analysis comparing DCIS treatments based on DCISionRT testing to traditional clinicopathologic risk factors.

PATIENTS AND METHODS

A Markov state transition model was constructed to perform a cost-effectiveness analysis comparing breast-conserving surgery with or without RT using DCISionRT testing vs. traditional clinicopathologic risk factors. Clinical parameters were obtained from clinical trial data and cross-validation studies. Cost data were based on 2019 Medicare reimbursement. Incremental cost-effectiveness ratio (ICER) was calculated as incremental cost per quality-adjusted life-year (QALY) gained comparing DCIS treatments using DCISionRT testing to traditional clinicopathologic risk factors and evaluated with a willingness-to-pay threshold of US$100,000 per QALY gained. To account for uncertainty, 1-way and probabilistic sensitivity analyses were performed.

RESULTS

Base case analysis showed that DCIS management using DCISionRT testing was a cost-effective strategy, resulting in an ICER of $74,331 per QALY gained compared to clinicopathology-based treatment. Model results were sensitive to a variation of the proportion of genomic-high, low-risk patients receiving RT in DCISionRT testing strategy, and changes in DCISionRT testing cost.

CONCLUSION

DCISionRT testing could potentially be a cost-effective strategy compared to traditional decision making for DCIS treatments, optimizing RT benefit based on an accurate recurrence risk assessment.

Interobserver Variability in Ductal Carcinoma In Situ of the Breast

OBJECTIVES

Since most patients with ductal carcinoma in situ (DCIS) of the breast are treated upon diagnosis, evidence on its natural progression to invasive carcinoma is limited. It is estimated that around half of the screen-detected DCIS lesions would have remained indolent if they had never been detected. Many patients with DCIS are therefore probably overtreated. Four ongoing randomized noninferiority trials explore active surveillance as a treatment option. Eligibility for these trials is mainly based on histopathologic features. Hence, the call for reproducible histopathologic assessment has never sounded louder.

METHODS

Here, the available classification systems for DCIS are discussed in depth.

RESULTS

This comprehensive review illustrates that histopathologic evaluation of DCIS is characterized by significant interobserver variability. Future digitalization of pathology, combined with development of deep learning algorithms or so-called artificial intelligence, may be an innovative solution to tackle this problem. However, implementation of digital pathology is not within reach for each laboratory worldwide. An alternative classification system could reduce the disagreement among histopathologists who use "conventional" light microscopy: the introduction of dichotomous histopathologic assessment is likely to increase interobserver concordance.

CONCLUSIONS

Reproducible histopathologic assessment is a prerequisite for robust risk stratification and adequate clinical decision-making. Two-tier histopathologic assessment might enhance the quality of care.

The challenge of avoiding over- and under-treatment in older women with ductal cancer in situ: A scoping review of existing knowledge gaps and a meta-analysis of real-world practice patterns

Ductal cancer in situ (DCIS) is mainly a screen-detected disease and although the risk for breast cancer is age-dependent, most screening programs do not include women over the age of 75 years. Older women are usually excluded from clinical trials and treatment practices are largely based on observational studies or extrapolation of trial results from younger patients, leading to either over- or under-treatment of this population. We systematically reviewed available electronic databases for DCIS treatment patterns and outcomes in older patients 15 years. Inclusion criteria allowed for randomised controlled trials, cohort studies, case-control and cross-sectional studies, as well as meta-analyses, systematic reviews and position papers. Results showed that, although elderly are not necessarily frail, they are generally treated as such by physicians, aiming to de-escalate therapeutic interventions. After adjusting for frailty, age seems to be a significant factor for less surgery; however, older women with DCIS are more probable to receive surgery than their counterparts with early invasive cancer. DCIS biology and subtypes are independent risk factors for local recurrence or progression to invasive carcinoma, if DCIS is under-treated. The end-benefit of surgery, radio- and endocrine-therapy depend on additional parameters, such as life expectancy, co-morbidities and competing risks of death. Screen-detected DCIS in older women is a challenging clinical problem, mainly due to the lack of high-level data. Therapeutic strategies should be tailored to life expectancy and performance status, DCIS features and patient preference, aiming at combining optimal oncological outcomes with maintenance of quality of life.

Treatment of Ductal Carcinoma in Situ: Considerations for Tailoring Therapy in the Contemporary Era

Purpose of Review

Standard options for the treatment of ductal carcinoma in situ (DCIS) include breast-conserving surgery (BCS) alone; BCS with radiotherapy or endocrine therapy, or both; and mastectomy. Survival is excellent with all options, but rates of local recurrence (LR) vary, as do quality-of-life measures. Here we discuss treatment outcomes, risk factors for LR, and tools for risk estimation.

Recent Findings

After BCS, radiotherapy reduces the risk of LR by half, and endocrine therapy reduces the risk by a third. Young age, inadequate margins, and greater volume of disease are associated with higher risk of LR after BCS, while young age, high grade, and microinvasion are associated with higher risk of locoregional recurrence after mastectomy. Clinical tools, including the Memorial Sloan Kettering Cancer Center (MSKCC) DCIS nomogram, provide LR risk estimates after BCS that appear more accurate than current genomic assays. The safety of active surveillance for seemingly low-risk patients remains uncertain.

Summary

Estimation of LR risk, utilizing a multitude of clinicopathologic and treatment factors, can help a woman balance that risk with her values and priorities, and allow her to choose the optimal treatment option for her.

Comparison of Local Recurrence Risk Estimates After Breast-Conserving Surgery for DCIS: DCIS Nomogram Versus Refined Oncotype DX Breast DCIS Score

BACKGROUND

A ductal carcinoma in situ (DCIS) Nomogram integrating 10 clinicopathologic/treatment factors and a Refined DCIS Score (RDS) that incorporates a genomic assay and three clinicopathologic factors (Oncotype DX DCIS Score) are available to estimate DCIS 10-year local recurrence risk (LRR). This study compared these estimates.

METHODS

Patients 50 years of age or older with DCIS size 2.5 cm or smaller and a genomic assay available were identified. An RDS within 1-2% of the range of Nomogram LRR estimates obtained by assuming use and non-use of endocrine therapy (Nomogram ± ET) was defined as concordant. Assuming a 10-year risk threshold of 10% for recommending radiation, Nomogram ± ET and RDS estimates were compared, and threshold concordance was determined.

RESULTS

For 54 (92%) of 59 patients, the RDS and Nomogram ± ET LRR estimates were concordant. For the remaining 5 (8%) of the 59 patients, the RDS LRR estimates were lower than the Nomogram + ET estimates, with an absolute difference of 3-8%, and thus were discordant. For these five patients, the RDS estimates of 10-year LRR were lower than 10% (range 5-8%) and the Nomogram + ET estimates were 10% or higher (range 11-14%). These five patients with both discordant and threshold-discordant estimates all had close margins (≤ 2 mm).

CONCLUSIONS

Among 92% of women 50 years of age or older with DCIS size 2.5 cm or smaller, free-of-charge online Nomogram 10-year LRR estimates were concordant with those obtained using the commercially available RDS (> $4600). Among the 8% with discordant risk estimates, the RDS appeared to underestimate the LRR and may lead to inappropriate omission of radiotherapy. Unless other data show a clinically significant advantage of the RDS (Oncotype DX DCIS Score), the study data suggest that for women 50 years of age or older with DCIS size 2.5 cm or smaller, its use is not warranted.

A retrospective alternative for active surveillance trials for ductal carcinoma in situ of the breast

Ductal carcinoma in situ (DCIS) of the breast is a nonobligate precursor of invasive breast cancer, accounting for 20 % of screen-detected breast cancers. Little is known about the natural progression of DCIS because most patients undergo surgery upon diagnosis. Many DCIS patients are likely being overtreated, as it is believed that only around 50 % of DCIS will progress to invasive carcinoma. Robust prognostic markers for progression to invasive carcinoma are lacking. In the past, studies have investigated women who developed a recurrence after breast-conserving surgery (BCS) and compared them with those who did not. However, where there is no recurrence, the patient has probably been adequately treated. The present narrative review advocates a new research strategy, wherein only those patients with a recurrence are studied. Approximately half of the recurrences are invasive cancers, and half are DCIS. So-called "recurrences" are probably most often the result of residual disease. The new approach allows us to ask: why did some residual DCIS evolve to invasive cancers and others not? This novel strategy compares the group of patients that developed in situ recurrence with the group of patients that developed invasive recurrence after BCS. The differences between these groups could then be used to develop a robust risk stratification tool. This tool should estimate the risk of synchronous and metachronous invasive carcinoma when DCIS is diagnosed in a biopsy. Identification of DCIS patients at low risk for developing invasive carcinoma will individualize future therapy and prevent overtreatment.

Predictors of an Invasive Breast Cancer Recurrence after DCIS: A Systematic Review and Meta-analyses

We performed a systematic review with meta-analyses to summarize current knowledge on prognostic factors for invasive disease after a diagnosis of ductal carcinoma in situ (DCIS). Eligible studies assessed risk of invasive recurrence in women primarily diagnosed and treated for DCIS and included at least 10 ipsilateral-invasive breast cancer events and 1 year of follow-up. Quality in Prognosis Studies tool was used for risk of bias assessment. Meta-analyses were performed to estimate the average effect size of the prognostic factors. Of 1,781 articles reviewed, 40 articles met the inclusion criteria. Highest risk of bias was attributable to insufficient handling of confounders and poorly described study groups. Six prognostic factors were statistically significant in the meta-analyses: African-American race [pooled estimate (ES), 1.43; 95% confidence interval (CI), 1.15-1.79], premenopausal status (ES, 1.59; 95% CI, 1.20-2.11), detection by palpation (ES, 1.84; 95% CI, 1.47-2.29), involved margins (ES, 1.63; 95% CI, 1.14-2.32), high histologic grade (ES, 1.36; 95% CI, 1.04-1.77), and high p16 expression (ES, 1.51; 95% CI, 1.04-2.19). Six prognostic factors associated with invasive recurrence were identified, whereas many other factors need confirmation in well-designed studies on large patient numbers. Furthermore, we identified frequently occurring biases in studies on invasive recurrence after DCIS. Avoiding these common methodological pitfalls can improve future study designs.

Management of Ductal Carcinoma In Situ (DCIS) of the Breast: Present Approaches and Future Directions

PURPOSE OF REVIEW

Ductal carcinoma in situ (DCIS; intraductal carcinoma) of the breast is commonly found in an asymptomatic woman on routine screening mammography. The purpose of this review is to describe current approaches to the management of DCIS as well as areas for future investigation.

RECENT FINDINGS

Randomized trials have demonstrated that adding radiation treatment after breast conservation surgery (lumpectomy; surgical excision) reduces the rate of ipsilateral local recurrence by about half, and that adding hormonal therapy reduces the rate of all breast cancer events (ipsilateral plus contralateral). Early clinical studies attempted to stratify the risk of recurrence using conventional clinical and pathologic features. More recent clinical studies have attempted to define prospectively patients with lower risk DCIS for whom omission of radiation treatment after lumpectomy is a reasonable option. Molecular profiling is a newer approach to define risk stratification for DCIS. Combining molecular profiling with clinical and pathologic features appears to be more accurate in defining and stratifying the risk of recurrence after lumpectomy. After lumpectomy for DCIS, risk stratification using clinical and pathologic characteristics, and more recently molecular profiling, can help guide clinical decision-making for the use of radiation treatment and hormonal therapy. Ongoing studies are evaluating the possibility of de-escalating therapy, and in some studies, even using core biopsy alone, without surgical excision.

Leveraging the variable natural history of ductal carcinoma in situ (DCIS) to select optimal therapy

PURPOSE

Ductal carcinoma in situ (DCIS) is a non-obligate precursor to invasive ductal carcinoma. The authors sought to discuss the evidence suggesting that not all DCIS will progress to invasive disease if left untreated.

RESULTS

Four lines of evidence align to suggest that not all of this in-situ disease progresses to invasive cancer: its prevalence on screening mammography, studies of missed diagnoses, incidental findings in autopsy specimens, and large retrospective reviews of those treated with excision alone.

CONCLUSION

A clearer understanding of the variable history of DCIS coupled with advances in genomic profiling of the disease holds the promise of reducing widespread over-treatment of this non-invasive cancer. Additionally, identification of higher risk of recurrence subsets may select patients for whom more aggressive treatment may be appropriate.

Clinical Trials for Ductal Carcinoma In Situ of the Breast

Ductal carcinoma in situ (DCIS) of the breast is a non-obligatory precursor to invasive breast carcinoma, with a variable natural history and biological potential for progression to invasive disease. Over the past 30 years, clinical trials have applied the therapeutic principles used for invasive carcinoma to treat DCIS (surgery, with or without breast radiotherapy, and post-operative endocrine therapy), with excellent survival outcomes, and in-breast recurrence rates that range from 0.5 to 1% annually. However, half of such recurrences are again in-situ lesions, and intensive therapy is likely not necessary for all patients. Current clinical research is focused on a better characterization of the potential of individual lesions to progress to invasive disease, and to identify women who would do well with lesser treatment. Three ongoing trials in the United States and Europe randomize women to active surveillance (with or without endocrine therapy) versus usual treatment with surgery and radiotherapy. The use of pre-operative endocrine therapy has been evaluated in a recently completed trial of letrozole use in postmenopausal women with DCIS; and in on-going trials of tamoxifen, used either orally, or as a 4-hydroxytamoxifen gel formulation for application to the breast skin. This review summaries the major past and current clinical trials of DCIS, and the likely trajectories of DCIS management in the near future.

Adjuvant radiation therapy in small ductal carcinoma in situ

BACKGROUND

The objective of this study was to evaluate ipsilateral breast tumor recurrence (IBTR) rates in patients with small (≤1 cm) ductal carcinoma in situ (DCIS) who were followed up for more than 15 years.

METHODS

We identified 209 patients with primary small (≤1 cm) DCIS without invasion who received curative excision with and without adjuvant radiation therapy (RT) from 1996 to 2009. IBTR rates and prognostic factors in all patients were estimated by univariate and multivariate analyses.

RESULTS

With a median follow-up of 104 months, eight (53.3%) had DCIS recurrence and seven (46.7%) had recurrence of invasive ductal carcinoma. IBTR rate of all patients was 7.5% at 10 years and 12.1% at 15 years. In univariate analysis, age and subtypes were significant factors for IBTR. In multivariate analysis, resection margin, adjuvant RT, and endocrine therapy were significant factors for IBTR.

CONCLUSIONS

IBTR rate of small (≤1 cm) DCIS following excision with or without adjuvant RT was 12.1% at 15 years. Adjuvant RT and endocrine therapy were associated with lower IBTR rate in small DCIS.