Ductal Carcinoma in Situ—The Influence of the Radiotherapy Boost on Local Control

Locoregional Control Benefit of a Tumor Bed Boost for Ductal Carcinoma In Situ

Purpose

Radiation therapy (RT) after breast-conserving surgery (BCS) for ductal carcinoma in situ (DCIS) reduces invasive and in situ recurrences. Whereas landmark studies suggest that a tumor bed boost improves local control for invasive breast cancer, the benefit in DCIS remains less certain. We evaluated outcomes of patients with DCIS treated with or without a boost.

Methods and Materials

The study cohort comprised patients with DCIS who underwent BCS at our institution from 2004 to 2018. Clinicopathologic features, treatment parameters, and outcomes were ascertained from medical records. Patient and tumor characteristics were evaluated relative to outcomes using univariable and multivariable Cox models. Recurrence-free survival (RFS) estimates were generated using the Kaplan-Meier method.

Results

We identified 1675 patients who underwent BCS for DCIS (median age, 56 years; interquartile range, 49-64 years). Boost RT was used in 1146 cases (68%) and hormone therapy in 536 (32%). At a median follow-up of 4.2 years (interquartile range, 1.4-7.0 years), we observed 61 locoregional recurrence events (56 local, 5 regional) and 21 deaths. Univariable logistic regression demonstrated that boost RT was more common among younger patients (P < .001) with positive or close margins (P < .001) and with larger tumors (P < .001) of higher grade (P = .025). The 10-year RFS rate was 88.8% among those receiving a boost and 84.3% among those without a boost (P = .3), and neither univariable nor multivariable analyses revealed an association between boost RT and locoregional recurrence.

Conclusions

Among patients with DCIS who underwent BCS, use of a tumor bed boost was not associated with locoregional recurrence or RFS. Despite a preponderance of adverse features among the boost cohort, outcomes were similar to those of patients not receiving a boost, suggesting that a boost may mitigate risk of recurrence among patients with high-risk features. Ongoing studies will elucidate the extent to which a tumor bed boost influences disease control rates.

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.

Enhanced radiotherapy efficacy of breast cancer multi cellular tumor spheroids through in-situ fabricated chitosan-zinc oxide bio-nanocomposites as radio-sensitizing agents

Overwhelming evidence has shown that three-dimensional multicellular tumor spheroids (MCTSs) as a mimic of in-vivo tumor can accurately exhibit cellular responses to treatments. So, we compared the capability of pure zinc oxide nanoparticles (ZnO-NPs) and chitosan-ZnO bio-nanocomposites (CS-ZnO BNCs) for enhancing the radiosensitization of MDA-MB-231 breast cancer cells (BCCs) in the 3D-MCTSs model. ZnO-NPs and CS-ZnO BNCs were synthesized by a facile co-precipitation method. FE-SEM images revealed that the uniform spherical ZnO-NPs with an average diameter of 35 nm were successfully dispersed on chitosan. MDA-MB-231 MCTSs which were formed in a non-adherent culture plate, possessed functional features of in-vivo tumor. The priority of such culture method to conventionally used 2D monolayer (or parental) cell culture is the mimicking of tumor microenvironment. The toxicity of CS-ZnO BNCs and ZnO-NPs against the MDA-M-231 BCCs was evaluated using MTT-colorimetric assay, which demonstrated superior biocompatibility of CS-ZnO BNCs compared to pure ZnO-NPs (even at high concentration of 100 μg/mL). Survival fraction analysis of cells under clinical X-ray irradiation (6 MV) showed that MCTSs had a higher radioresistance compared to parental cells. Besides, the clonogenic potential of irradiated MCTSs was significantly decreased by the addition of CS-ZnO BNCs similar to that of monolayer cells. The sensitivity enhancement ratios (SER) for MCTSs and monolayer cells were calculated 1.5 and 1.63, respectively. Further, tracking of radiobiological properties and apoptosis induction of MCTSs showed that CS-ZnO BNCs not only could lead to the creation of higher radiation-induced complex DNA break and apoptosis death in MCTSs, but also weakened DNA repair mechanisms. It was found that non-toxic concentration of CS-ZnO BNCs has promising potential to enhance radiosensitivity of resistant-MCTSs as a superior in-vitro tumor model. So, CS-ZnO BNCs can be a prominent candidate for overcoming the resistance of BCCs to radiotherapy.

The Selection of Treatment Modality for Breast Ductal Carcinoma In Situ: Experience From a Single Institution

Purpose:

Although breast conservation surgery(BCS) followed by adjuvant radiotherapy is now the mainstream treatment method for breast ductal carcinoma in situ(DCIS), mastectomy is still performed in some patients who refuse to undergo radiation. However, the most effective treatment method for these patients is still unknown. In the current study, we aimed to compare the survival rates between mastectomy and BCS plus adjuvant radiotherapy in patients with DCIS.

Materials and Methods:

We performed a retrospective study of 333 patients with DCIS from May 2004 to December 2016. There were 209 patents who were treated with BCS and adjuvant radiotherapy, while the remaining of 124 patients underwent mastectomy. The disease-free survival (DFS) and local recurrence-free survival(LRFS) rates were compared between the 2 treatment groups. Cox proportional hazards regression was performed to explore factors associated with DFS and LRFS.

Results:

The 10-year local recurrence(LR) rates in the mastectomy and BCS plus adjuvant radiotherapy groups were 2.6% and 7.5%, respectively. There was no difference in the LR rate between the 2 groups. Furthermore the DFS rate was also similar between the mastectomy and BCS plus adjuvant radiotherapy groups. Based on the multivariable analysis, age and tumor grade were significantly correlated with the LRFS and DFS rates. In the subgroup analysis based on the factors of age and tumor grade, patients with a tumor grade of III who underwent mastectomy had better LRFS and DFS rates compared to those who received BCS plus radiotherapy.

Conclusion:

In patients with DCIS, the long-term efficacy was similar between mastectomy and BCS followed by adjuvant radiotherapy. However, in the subgroup of patients with grade III tumors, mastectomy seems to offer a better LRFS and DFS than BCS plus radiotherapy.

Practical consensus recommendations regarding role of postmastectomy radiation therapy

The use of radiation therapy after mastectomy (PMRT) has been limited to those patients who are at significant risk of cancer recurring in the chest wall or in the nodal basins. The use of PMRT has been widely accepted for patients with four or more positive lymph nodes,^[1],[2] but there is still controversy regarding the value of PMRT for those with one to three positive nodes. This expert group used data from published literature, practical experience and opinion of a large group of academic oncologists to arrive at these practical consensus recommendations for the benefit of community oncologists.

The 2018 assisi think tank meeting on breast cancer: International expert panel white paper

We report on the second Assisi Think Tank Meeting (ATTM) on breast cancer which was held under the auspices of the European Society for RadioTherapy & Oncology (ESTRO). In discussing in-depth current evidence and practice it was designed to identify grey areas in diverse forms of the disease. It aimed at addressing uncertainties and proposing future trials to improve patient care. Before the meeting, three key topics were selected: 1) primary systemic therapy, mastectomy, breast reconstruction and post-mastectomy radiation therapy, 2) therapeutic options in ductal carcinoma in situ, and 3) therapy de-escalation in early stage breast cancer. Clinical practice in these areas was investigated by means of an online questionnaire. The time lapse period between the survey and the meeting was used to review the literature and on-going clinical trials. At the ATTM both were discussed in depth and research protocols were proposed.

Treatment results in patients with ductal carcinoma in situ treated with adjuvant radiotherapy

Background/aim

The aim of this study was to evaluate the treatment results of patients undergoing adjuvant radiotherapy (ART) after breast surgery with the diagnosis of ductal carcinoma in situ (DCIS).

Materials and methods

A total of 61 women who had undergone radiotherapy following extensive surgical excision were enrolled. All patients underwent 50 Gy ART. Survival analysis was performed using Kaplan–Meier analysis and SPSS 20.0.

Results

The median age was 52 years (range: 28–86). The median follow-up period after RT was 92 months (range: 23–237). The median overall survival and distant and regional recurrence-free and disease-specific survival was 96 months (range: 26–240), while disease-free and local recurrence-free survival was 96 months (range: 22–240). While the 15-year and 20-year overall survival rates were 87% and 87%, respectively, the recurrence-free survival rates were 98% and 98%, respectively; the rates of disease-specific survival were 100% and 100%, respectively.

Conclusion

The results of this study with a long follow-up period have shown that ART in DCIS is an effective treatment method to provide local disease control. However, further large studies are needed to identify the prognostic factors.

Radiosensitizing effect of curcumin-loaded lipid nanoparticles in breast cancer cells

In breast cancer (BC) care, radiotherapy is considered an efficient treatment, prescribed both for controlling localized tumors or as a therapeutic option in case of inoperable, incompletely resected or recurrent tumors. However, approximately 90% of BC-related deaths are due to the metastatic tumor progression. Then, it is strongly desirable to improve tumor radiosensitivity using molecules with synergistic action. The main aim of this study is to develop curcumin-loaded solid nanoparticles (Cur-SLN) in order to increase curcumin bioavailability and to evaluate their radiosensitizing ability in comparison to free curcumin (free-Cur), by using an in vitro approach on BC cell lines. In addition, transcriptomic and metabolomic profiles, induced by Cur-SLN treatments, highlighted networks involved in this radiosensitization ability. The non tumorigenic MCF10A and the tumorigenic MCF7 and MDA-MB-231 BC cell lines were used. Curcumin-loaded solid nanoparticles were prepared using ethanolic precipitation and the loading capacity was evaluated by UV spectrophotometer analysis. Cell survival after treatments was evaluated by clonogenic assay. Dose–response curves were generated testing three concentrations of free-Cur and Cur-SLN in combination with increasing doses of IR (2–9 Gy). IC₅₀ value and Dose Modifying Factor (DMF) was measured to quantify the sensitivity to curcumin and to combined treatments. A multi-“omic” approach was used to explain the Cur-SLN radiosensitizer effect by microarray and metobolomic analysis. We have shown the efficacy of the Cur-SLN formulation as radiosensitizer on three BC cell lines. The DMFs values, calculated at the isoeffect of SF = 50%, showed that the Luminal A MCF7 resulted sensitive to the combined treatments using increasing concentration of vehicled curcumin Cur-SLN (DMF: 1,78 with 10 µM Cur-SLN.) Instead, triple negative MDA-MB-231 cells were more sensitive to free-Cur, although these cells also receive a radiosensitization effect by combination with Cur-SLN (DMF: 1.38 with 10 µM Cur-SLN). The Cur-SLN radiosensitizing function, evaluated by transcriptomic and metabolomic approach, revealed anti-oxidant and anti-tumor effects. Curcumin loaded- SLN can be suggested in future preclinical and clinical studies to test its concomitant use during radiotherapy treatments with the double implications of being a radiosensitizing molecule against cancer cells, with a protective role against IR side effects.

Current Therapeutic Approaches to DCIS

Treatment for ductal carcinoma in-situ (DCIS) has historically been extrapolated from studies of invasive breast cancer. Accepted local therapy approaches range from small local excisions, with or without radiation, to bilateral mastectomies. Systemic treatment with endocrine therapy is often recommended for hormone positive patients. With improvements in imaging, pathologic review, and treatment techniques in the modern era, combined with new information regarding tumor biology, the management of DCIS is rapidly evolving. A multidisciplinary approach to treatment is now more important than ever, with a shift towards de-escalating therapy to reduce treatment related toxicity. This review focuses on nuances of clinical management of DCIS in the modern era, highlighting key differences between DCIS as compared to invasive breast cancer. The American Cancer Society (ACS) currently recommends beginning screening with annual mammograms for women age 45, with the option to start at age 40. As treatment of DCIS has not been shown to impact survival, the USPSTF has more conservative screening recommendations of biennial mammograms from age 50-74. Unlike invasive breast cancer, DCIS is almost exclusively diagnosed by mammographic detection, and lymph node evaluation is not recommended. Pathologic review of biopsy specimens should follow the guidelines of the College of American Pathologists. Surgical management options include breast conservation, mastectomy, or possibly nipple sparing mastectomy, with upfront sentinel lymph node evaluation in the case of mastectomy. Radiation therapy is generally recommended as a component of breast conserving therapy for patients with DCIS, though in some low risk patients, there is trial data to suggest that adjuvant radiation may be omitted. Techniques for minimizing radiation toxicity should always be emphasized. Endocrine therapy is offered to women with hormone positive DCIS who have undergone lumpectomy for risk reduction, and has the benefit of decreasing incidence of events in both the ipsilateral and contralateral breast. More recent studies have explored use of targeted treatments such as trastuzumab in DCIS for HER2 overexpression. Future directions include tailoring therapy based on patient characteristics and tumor biology. With so many different options for treatment, it is also critical to engage in a discussion with the patient to arrive at a treatment decision that balances patient preferences for disease control versus treatment toxicity, financial toxicity, cosmesis, and quality of life.

A national multicenter study on 1072 DCIS patients treated with breast-conserving surgery and whole breast radiotherapy (COBCG-01 study)

BACKGROUND AND PURPOSE

Breast-conserving surgery (BCS) and whole breast radiation (RT) with or without endocrine therapy (ET) represent the standard of care for ductal carcinoma in situ (DCIS). The use of adjuvant treatments after surgery is still controversial in this setting. We performed a retrospective multicenter analysis on a series of DCIS patients treated with BCS and adjuvant RT.

MATERIALS AND METHODS

We collected clinical data from nine Italian centers on 1072 women having a diagnosis of DCIS and treated between 1997 and 2012. We reported on the 5- and 10-year local recurrence (LR) rates, overall survival, and breast cancer specific survival (BCSS) employing the Kaplan-Meier method.

RESULTS

At a median follow-up of 8.4 years, 67 LR (6.3%) and 47 deaths (4.4%) were observed. LR rates at 5 and 10 years were 3.4% and 7.6%, respectively. BCSS rates at 5 and 10 years were 99.7% and 99.1%, respectively. At univariate regression analysis, postmenopausal state (p = 0.009), estrogen receptor (ER) (p = 0.0001) and progesterone receptor (p = 0.018) positivity and ET (p = 0.006) were inversely correlated with LR. Final surgical margins (FSM) status <1 mm was significantly correlated with higher LR (p = 0.003). At multivariate regression analysis postmenopausal state (p = 0.03), and ER positive (p = 0.045) maintained the significant favorable feature, while FSM <1 mm (p = 0.024) confirmed its negative impact on LR.

CONCLUSIONS

Our real-life study pointed out the significant favorable prognostic role of postmenopausal state and ER positive status on LR occurrence. FSM <1 mm was significantly correlated to a higher chance to experience LR.

Oncoplastic breast surgery for the management of ductal carcinoma in situ (DCIS): is it oncologically safe? A retrospective cohort analysis

BACKGROUND

Few data exist in literature regarding oncoplastic surgery (ONC) and ductal carcinoma in situ (DCIS). The role of ONC in the treatment of DCIS has not been elucidated yet: no case-control study has yet been published on the issue and no long-term oncologic results are reported.

METHODS

Using the European Institute of Oncology (IEO) institutional breast cancer data base we investigated the oncologic safety of ONC for DCIS comparing a consecutive series of 44 patients who have underwent ONC followed by external irradiation for DCIS (Group A-study group) with 375 patients who received conservation alone followed by external irradiation for DCIS (Group B control group) in the same period. We excluded patients presenting with secondary tumors or local relapses and those requiring re-excision or completion mastectomy for positive margins. Primary endpoints were disease-free survival (DFS) and ipsilateral breast tumor recurrence (IBTR) within the study group and comparison with the control group.

RESULTS

Events rates and death rates were similar in the two groups. The average annual rate of invasive IBTR in group A and B was 1.6% and 1.0% respectively. No difference in the rate of lymphnode metastasis, distant metastasis, contralateral breast cancer, other primary cancer or death was observed across the two groups.

CONCLUSIONS

Our findings suggest the safety of ONC and irradiation for the management of DCIS extending the indications for conservation in DCIS patients otherwise treated with mastectomy. It provides the best available evidence supporting ONC as a valid treatment option for the management of DCIS.

Tumor Resection Margin Definitions in Breast-Conserving Surgery: Systematic Review and Meta-analysis of the Current Literature

Worldwide, various guidelines recommend what constitutes an adequate margin of excision for invasive breast cancer or for ductal carcinoma-in-situ (DCIS). We evaluated the use of different tumor resection margin guidelines and investigated their impact on positive margin rates (PMR) and reoperation rates (RR). Thirteen guidelines reporting on the extent of a positive margin were reviewed along with 31 studies, published between 2011 and 2016, reporting on a well-defined PMR. Studies were categorized according to the margin definition. Pooled PMR and RR were determined with random-effect models. For invasive breast cancer, most guidelines recommend a positive margin of tumor on ink. However, definitions of reported positive margins in the clinic vary from more than focally positive to the presence of tumor cells within 3 to 5 mm from the resection surface. Within the studies analyzed (59,979 patients), pooled PMRs for invasive breast cancer ranged from 9% to 36% and pooled RRs from 77% to 99%. For DCIS, guidelines vary between no DCIS on the resection surface to DCIS cells found within a distance of 2 mm from the resection edge. Pooled PMRs for DCIS varied from 4% to 23% (840 patients). Given the differences in tumor margin definition between countries worldwide, quality control data expressed as PMR or RR should be interpreted with caution. Furthermore, the overall definition for positive resection margins for both invasive disease and DCIS seems to have become more liberal.

Hypofractionated volumetric modulated arc therapy in ductal carcinoma in situ: toxicity and cosmetic outcome from a prospective series

OBJECTIVE

Hypofractionated radiotherapy in early stage breast cancer is an effective adjuvant treatment, but there is a lack of randomized data for patients with ductal carcinoma in situ (DCIS). The aim of this study is the evaluation of skin toxicity and cosmesis, and early clinical outcome of DCIS patients enrolled in an institutional Phase II trial of hypofractionated breast irradiation.

METHODS

137 DCIS patients were enrolled in the trial. All patients underwent volumetric modulated arc therapy (VMAT) to the whole breast with a total dose of 40.5 Gy in 15 fractions over 3 weeks, without tumour bed boost. Acute and late skin toxicities were recorded. Cosmetic outcomes were assessed as excellent/good or fair/poor. Early clinical outcome was reported.

RESULTS

Median age was 58 y.o. (range 30-86). The median follow-up time was 22 months (range 6-45). At the end of the radiotherapy, skin toxicity was grade G1 in 56% of the patients, G2 in 15%, no patients presented G3 toxicity. In the range of 3-9 months of follow-up, the skin toxicity was G1 in 28% of patients, no G2-G3 cases; cosmetic outcome was good/excellent in 95% of patients. In the follow-up interval of 9-24 months, the skin toxicity was G1 in 12% of patients, no G2-G3 toxicity; cosmetic outcome was good/excellent in 96% of patients. After an early evaluation of clinical outcomes, 5 patients (3.6%) presented an in-breast recurrence.

CONCLUSION

Hypofractionated radiotherapy using VMAT is a viable option for DCIS. A longer follow-up is needed to assess clinical outcomes and late toxicity. Advances in knowledge: The use of hypofractionated VMAT is dosimetrically feasible for treating breast DCIS.

Association of Radiotherapy Boost for Ductal Carcinoma In Situ With Local Control After Whole-Breast Radiotherapy

Importance

The use of a radiotherapy (RT) boost to the tumor bed after whole-breast RT (WBRT) for ductal carcinoma in situ (DCIS) is largely extrapolated from invasive cancer data, but robust evidence specific to DCIS is lacking.

Objective

To compare ipsilateral breast tumor recurrence (IBTR) in women with DCIS treated with vs without the RT boost after breast-conserving surgery and WBRT.

Design, Setting, and Participants

This retrospective analysis pooled deidentified patient-level data from 10 academic institutions in the United States, Canada, and France from January 1, 1980, through December 31, 2010. All patients had newly diagnosed pure DCIS (no microinvasion), underwent breast-conserving surgery, and received WBRT with or without the boost with a minimum of 5 years of follow-up required for inclusion in the analysis. Given the limited events after WBRT, an a priori power analysis was conducted to estimate the DCIS sample size needed to detect the anticipated benefit of the boost. Data were uniformly recoded at the host institution and underwent primary and secondary reviews before analysis. Sample size calculations (ratio of patients who received the boost dose to those who did not, 2:1; α = .05; power = 80%) estimated that 2982 cases were needed to detect a difference of at least 3%. The final analysis included 4131 patients (2661 in the boost group and 1470 in the no-boost group) with a median follow-up of 9 years and media boost dose of 14 Gy. Data were collected from July 2011 through February 2014 and analyzed from March 2014 through August 2015.

Interventions

Radiotherapy boost vs no boost.

Main Outcomes and Measures

Ipsilateral breast tumor recurrence.

Results

The analysis included 4131 patients (median [SD] age, 56.1 [10.9] years; range, 24-88 years). Patients with positive margins, unknown estrogen receptor status, and comedo necrosis were more likely to have received an RT boost. For the entire cohort, the boost was significantly associated with lower IBTR (hazard ratio [HR], 0.73; 95% CI, 0.57-0.94; P = .01) and with IBTR-free survival (boost vs no-boost groups) of 97.1% (95% CI, 0.96-0.98) vs 96.3% (95% CI, 0.95-0.97) at 5 years, 94.1% (95% CI, 0.93-0.95) vs 92.5% (95% CI, 0.91-0.94) at 10 years, and 91.6% (95% CI, 0.90-0.93) vs 88.0% (95% CI, 0.85-0.91) at 15 years. On multivariable analysis accounting for confounding factors, the boost remained significantly associated with reduced IBTR (HR compared with no boost, 0.68; 95% CI, 0.50-0.91; P = .01) independent of age and tamoxifen citrate use.

Conclusions and Relevance

This patient-level analysis suggests that the RT boost confers a statistically significant benefit in decreasing IBTR across all DCIS age groups, similar to that seen in patients with invasive breast cancer. These findings suggest that a DCIS RT boost to the tumor bed could be considered to provide an added incremental benefit in decreasing IBTR after a shared discussion between the patient and her radiation oncologist.

Patterns of Fractionation and Boost Usage in Adjuvant External Beam Radiotherapy for Ductal Carcinoma in Situ in the United States

BACKGROUND

While the roles of hypofractionated (HFxn) radiotherapy and lumpectomy boost in the adjuvant management of invasive breast cancer are supported by the results of clinical trials, randomized data supporting their use for ductal carcinoma in situ (DCIS) are forthcoming. We sought to evaluate current national trends and identify factors associated with HFxn and boost usage using the National Cancer Database.

PATIENTS AND METHODS

We queried the National Cancer Database for women diagnosed with DCIS from 2004 to 2014 undergoing external beam radiotherapy after breast conservation surgery. Patients were categorized as receiving either conventional fractionation (CFxn) or HFxn and as either receiving or not receiving a boost. Multiple logistic regression was performed to identify demographic, clinical, and treatment factor associations.

RESULTS

A total of 101,615 women were identified, with 87,641 (86.2%) receiving CFxn, 13,974 (13.8%) receiving HFxn, and most patients in each group (84.9% and 57.7%, respectively) receiving a boost. Implementation of HFxn increased from 4.3% in 2004 to 33.0% in 2014, and the use of a boost declined from 83.3% to 74.6%. HFxn receipt was independently associated with later year of diagnosis, older age, higher income, greater distance from treatment facility, greater facility volume, academic facility type, Western residence, smaller lesions, and nonreceipt of a boost. Factors associated with boost receipt included earlier year of diagnosis, younger age, higher income, community facility type, adverse pathologic features, and nonreceipt of HFxn.

CONCLUSION

Although CFxn with a boost remains the most common external beam radiotherapy strategy for DCIS, implementation of HFxn without a boost appears to be increasing. Practice patterns at present seem to be driven by guidelines for invasive breast cancer and nonclinical factors.

Adjuvant therapy in patients with ductal carcinoma in situ of the breast: The Pandora's box

Most patients with ductal carcinoma in situ of the breast (DCIS) are eligible for breast conservation treatment. The key management decision is whether to add radiotherapy and/or endocrine therapy to minimize the risk of a subsequent recurrence. Recent analyses indicating a lack of benefit in terms of breast cancer-associated mortality have suggested that more conservative approaches, omitting adjuvant therapy or even surgery, may be advisable in selected patients. These mortality observations are directly influenced by widespread use of mammographic screening which has opened a Pandora's box of subclinical DCIS and early invasive lesions. Confusion as to how aggressively such possibly indolent lesions should be treated has led to misunderstandings among patients and medical professionals. While awaiting further prospective evidence from clinical trials, we endorse an active treatment of DCIS as the standard of care. Our rationale is twofold: invasive recurrences are associated with an increase in breast cancer mortality, which is not the only relevant endpoint for DCIS. The benefit of complete surgical excision, adjuvant radiotherapy and endocrine treatment in preventing recurrence and invasive progression has been demonstrated in DCIS. The challenge now is how to identify DCIS patients who will not progress to invasive carcinoma even without complete excision and, at the other extreme, those patients at the highest risk who require mastectomy for local control. The current controversies over whether and which adjuvant therapy should be implemented can at least in part be addressed by developing effective doctor-patient communications that enable mutual understanding about the management of this biologically heterogeneous disease.

Breast-conserving treatment for ductal carcinoma in situ: Impact of boost and tamoxifen on local recurrences

PURPOSE

Ductal carcinoma in situ represents 15 to 20% of all breast cancers. Breast-conserving surgery and whole breast irradiation was performed in about 60% of the cases. This study reports local recurrence rates in patients with ductal carcinoma in situ treated by breast-conserving surgery and whole breast irradiation with or without boost and/or tamoxifen and compares different therapeutic options in two European countries.

PATIENTS AND METHODS

From 1998 to 2007, 819 patients with pure ductal carcinoma in situ were collected, both in France (266) and Italy (553). Median age was 56. All underwent breast-conserving surgery and whole breast irradiation; 391 (48%) received a boost (55% in France and 45% in Italy, P=0.017) and 173 (22.5%) tamoxifen (4.5% in France and 32% in Italy, P<0.0001).

RESULTS

With a 90-month median follow-up, there were 51 local recurrences (6.2%), including 27 invasive (53%). The 5- and 10-year local recurrence rates were 4% and 8.6%. Two patients developed axillary recurrence and 12 (1.5%) metastases (seven after invasive local recurrence); 41 (5%) patients had contralateral breast cancer. In the multivariate analysis, high nuclear grade and lack of tamoxifen are the most powerful predictors of local recurrence, with 2.6 (95% confidence interval [95% CI]: 1.74-3.89, P=0.0012) and 2.85 (95% CI: 1.42-5.72, P=0.04) odds ratio (OR) estimates, respectively. Age, margin status and boost did not influence local recurrence rates.

CONCLUSIONS

This study confirms the ductal carcinoma in situ treatment heterogeneity among countries and the unfavourable prognostic role of nuclear grade. Tamoxifen reduces local recurrence rates and might be considered for some subgroups of patients, but further confirmation is required. The boost usefulness still remains unclear.

Radiotherapy of Ductal Carcinoma In Situ

Ductal carcinoma in situ (DCIS) is a heterogeneous disease in both its biology and clinical course. In the past, recurrence rates after breast-conserving surgery have been as high as 30% after 10 years. The introduction of mammography screening and advances in imaging have led to an increase in the detection of DCIS. The focus of this review is on the role of radiotherapy in the multidisciplinary treatment, including current developments in hypofractionation and boost delivery, and attempts to define low-risk subsets of DCIS for which the need for adjuvant radiation is repeatedly questioned.

The role of boost and hypofractionation as adjuvant radiotherapy in patients with DCIS: a meta-analysis of observational studies

PURPOSE

The purpose of this meta-analysis is to summarize the current evidence on the role of boost and the efficacy of hypofractionated radiotherapy in patients with ductal cancer in situ (DCIS) after surgery and grade the quality of evidence.

MATERIALS AND METHODS

A comprehensive systematic electronic search through MEDLINE and the Cochrane Library as well as through the major international congresses' proceedings was conducted. Studies were considered eligible if they investigated the efficacy of hypofractionated vs. standard radiotherapy or the efficacy of boost vs. no boost in patients with DCIS. The outcome of interest was the number of local recurrences. Pooled estimates were calculated by using standard meta-analytic procedures.

RESULTS

Thirteen trials were considered eligible and were further analyzed. No difference in the risk of local recurrence was observed between the patients that received boost vs. no boost in the general cohort (12 studies, 6943 patients; Odds Ratio (OR): 0.91, 95% confidence interval (CI): 0.77-1.08, very low level of evidence). However, we found a reduced risk for local recurrence when boost was administered in patients with positive margins compared to no boost (6 studies, 811 patients; OR: 0.56, 95% CI: 0.36-0.87, very low level of evidence). No difference in local recurrence rate between patients who received hypofractionated versus standard radiotherapy was observed (4 studies, 2534 patients; OR: 0.78, 95% CI: 0.58-1.03, low level of evidence).

CONCLUSION

Hypofractionated radiotherapy seems to be a safe option in patients with DCIS after breast-conserving surgery while the addition of boost reduces the risk for local recurrence in the presence of positive margins. However, the level of evidence for these observations ranges between very low and low and the results of the ongoing randomized trials are necessary to confirm the results with higher level of evidence.

Validation of a nomogram in the prediction of local recurrence risks after conserving surgery for Asian women with ductal carcinoma in situ of the breast

AIMS

At our centre, ductal carcinoma in situ (DCIS) was commonly treated with breast-conservation therapy (BCT). Local recurrence after BCT is a major concern. The aims of our study were to review the outcomes of DCIS treatment in our patients and to evaluate a nomogram from Memorial Sloan Kettering Cancer Centre (MSKCC) for predicting ipsilateral breast tumour recurrence (IBTR) in our Asian population.

MATERIALS AND METHODS

Chart reviews of 716 patients with pure DCIS treated from 1992 to 2011 were carried out. Univariable Cox regression analyses were used to evaluate the effects of the 10 prognostic factors of the MSKCC nomogram on IBTR. We constructed a separate National Cancer Centre Singapore (NCCS) nomogram based on multivariable Cox regression via reduced model selection by applying the stopping rule of Akaike's information criterion to predict IBTR-free survival. The abilities of the NCCS nomogram and the MSKCC nomogram to predict IBTR of individual patients were evaluated with bootstrapping of 200 sets of resamples and the NCCS dataset, respectively. Harrell's c-index was calculated for each nomogram to evaluate the concordance between predicted and observed responses of individual subjects.

RESULTS

Study patients were followed up for a median of 70 months. Over 95% of patients received adjuvant radiotherapy. The 5 and 10 year actuarial IBTR-free survival rates for the cohort were 95.5 and 92.6%, respectively. In the multivariate analysis, independent prognostic factors for IBTR included use of adjuvant endocrine therapy, presence of comedonecrosis and younger age at diagnosis. These factors formed the basis of the NCCS nomogram, which had a similar c-index (NCCS: 0.696; MSKCC: 0.673) compared with the MSKCC nomogram.

CONCLUSION

The MSKCC nomogram was validated in an Asian population. A simpler NCCS nomogram using a different combination of fewer prognostic factors may be sufficient for the prediction of IBTR in Asians, but requires external validation to compare for relative performance.

Influence of boost radiotherapy in patients with ductal carcinoma in situ breast cancer: a multicenter, retrospective study in Korea (KROG 11-04)

To estimate the effect of boost radiotherapy on local recurrence-free survival (LRFS) in patients with ductal carcinoma in situ (DCIS) breast cancer. We included patients from nine institutions who met the following criteria: having Tis, age 18 years or older, having breast conserving surgery (BCS) and radiotherapy within 12 weeks after surgery. From 1995 through 2006, 728 patients were analyzed retrospectively by the Korean Radiation Oncology Group. All patients received whole-breast radiation therapy (WBRT) after BCS. 232 patients (31.9 %) also received boost radiation therapy (RT) (median 10 Gy). After median follow-up of 82 months, 5-year LRFS was 98.4 % and 10-year LRFS was 95.8 % for all patients. There was no statistically significant difference of LRFS between the boost and no-boost groups. Nineteen (2.6 %) patients had ipsilateral breast recurrences, including 12 of invasive recurrence and 7 DCIS. The presence of the HER2 receptor was associated with more invasive recurrences. Nine (1.2 %) patients developed contralateral breast cancer, including six invasive breast cancer and three DCIS. In the multivariate analysis, only the margin status was a significant prognostic factor for LRFS. Boost RT was not associated with further improvement of local control in DCIS after BCS and WBRT. HER2 receptor-positive patients may need further treatment with the anti-HER2 agents.

Treatment outcome of ductal carcinoma in situ patients treated with postoperative radiation therapy

Purpose

To evaluate the outcome of ductal carcinoma in situ (DCIS) patients who underwent surgery followed by radiation therapy (RT).

Materials and Methods

We retrospectively reviewed 106 DCIS patients who underwent surgery followed by postoperative RT between 1994 and 2006. Ninety-four patients underwent breast-conserving surgery, and mastectomy was performed in 12 patients due to extensive DCIS. Postoperative RT was delivered to whole breast with 50.4 Gy/28 fx. Tumor bed boost was offered to 7 patients (6.6%). Patients with hormonal receptor-positive tumors were treated with hormonal therapy.

Results

The median follow-up duration was 83.4 months (range, 33.4 to 191.5 months) and the median age was 47.8 years. Ten patients (9.4%) had resection margin <1 mm and high-grade and estrogen receptor-negative tumors were observed in 39 (36.8%) and 20 (18.9%) patients, respectively. The 7-year ipsilateral breast tumor recurrence (IBTR)-free survival rate was 95.3%. Resection margin (<1 or ≥1 mm) was the significant prognostic factor for IBTR in univariate and multivariate analyses (p < 0.001 and p = 0.016, respectively).

Conclusion

Postoperative RT for DCIS can achieve favorable treatment outcome. Resection margin was the important prognostic factor for IBTR in the DCIS patients who underwent postoperative RT.

[Breast ductal carcinoma in situ with microinvasion: pathological review and clinical implications]

PURPOSE

Recent improvements in the detection of breast cancer at an early stage have resulted in a rising incidence of breast ductal carcinoma in situ with microinvasion. So far, there is no consensus regarding its optimal management. We hereby report on our 10-year single institutional experience in breast ductal carcinoma in situ with microinvasion including pathological reviewing.

PATIENTS AND METHODS

All consecutive patients treated for a ductal carcinoma in situ with microinvasion at the Institut Claudius-Regaud (Toulouse, France) over a 10-year period were included in this study. We reviewed all available histological materials.

RESULTS

Sixty-three patients were eligible for this study. Two patients presented with a lymph node invasion at diagnosis. Each patient benefited from initial surgical management, which consisted either in mastectomy (n=25) or conservative resection (n=37). Axillary exploration was performed in 52 patients (82%). After a median follow-up of 61.3 months [46.9;69], the 5-year overall survival and disease free survival were 98.2 (95% CI=[88.2;99.7]) and 89.5% (95% CI=[76.3;95.6]) respectively. Two delayed invasive relapses occurred leading to one specific death. The pathological review highlighted a trend towards a loss of HR and HER2 expression (9%) in the microinvasive component in comparison with its surrounded in situ carcinoma.

CONCLUSION

The risk of initial lymph node involvement and delayed invasive local relapse deserve an optimal locoregional management including lymph node evaluation. The non-negligible discrepancy's rate between in situ and microinvasive components justifies HR status and HER2 expression assessment on the microinvasive component.

Hypofractionated radiation therapy for breast ductal carcinoma in situ

PURPOSE

Conventional radiation therapy (RT) administered in 25 fractions after breast-conserving surgery (BCS) is the standard treatment for ductal carcinoma in situ (DCIS) of the breast. Although accelerated hypofractionated regimens in 16 fractions have been shown to be equivalent to conventional RT for invasive breast cancer, few studies have reported results of using hypofractionated RT in DCIS.

METHODS AND MATERIALS

In this multicenter collaborative effort, we retrospectively reviewed the records of all women with DCIS at 3 institutions treated with BCS followed by hypofractionated whole-breast RT (WBRT) delivered in 16 fractions.

RESULTS

Between 2003 and 2010, 440 patients with DCIS underwent BCS followed by hypofractionated WBRT in 16 fractions for a total dose of 42.5 Gy (2.66 Gy per fraction). Boost RT to the surgical bed was given to 125 patients (28%) at a median dose of 10 Gy in 4 fractions (2.5 Gy per fraction). After a median follow-up time of 4.4 years, 14 patients had an ipsilateral local relapse, resulting in a local recurrence-free survival of 97% at 5 years. Positive surgical margins, high nuclear grade, age less than 50 years, and a premenopausal status were all statistically associated with an increased occurrence of local recurrence. Tumor hormone receptor status, use of adjuvant hormonal therapy, and administration of additional boost RT did not have an impact on local control in our cohort. On multivariate analysis, positive margins, premenopausal status, and nuclear grade 3 tumors had a statistically significant worse local control rate.

CONCLUSIONS

Hypofractionated RT using 42.5 Gy in 16 fractions provides excellent local control for patients with DCIS undergoing BCS.

Ductal carcinoma in situ of the breast

Ductal carcinoma in situ (DCIS) of the breast represents a complex, heterogeneous pathologic condition in which malignant epithelial cells are confined within the ducts of the breast without evidence of invasion. The increased use of screening mammography has led to a significant shift in the diagnosis of DCIS, accounting for approximately 27% of all newly diagnosed cases of breast cancer in 2011, with an overall increase in incidence. As the incidence of DCIS increases, the treatment options continue to evolve. Consistent pathologic evaluation is crucial in optimizing treatment recommendations. Surgical treatment options include breast-conserving surgery (BCS) and mastectomy. Postoperative radiation therapy in combination with breast-conserving surgery is considered the standard of care with demonstrated decrease in local recurrence with the addition of radiation therapy. The role of endocrine therapy is currently being evaluated. The optimization of diagnostic imaging, treatment with regard to pathological risk assessment, and the role of partial breast irradiation continue to evolve.

Radiotherapy after conservative surgery in ductal carcinoma in situ of the breast: a review

Several large prospective and retrospective studies have demonstrated excellent long-term outcomes after breast conservative treatment with radiation in invasive breast cancer. Breast-conserving surgery (BCS) followed by radiotherapy (RT) is an accepted management strategy for patients with DCIS. Adding radiation treatment after conservative surgery enables to reduce, without any significant risks, the rate of local recurrence (LR) by approximately 50% in retrospective and randomized clinical trials. As about 50% of LRs are invasive and have a negative psychological impact, minimizing recurrence is important. Local and local-regional recurrences after initial breast conservation treatment with radiation can be salvaged with high rates of survival and freedom from distant metastases.

Role of the radiotherapy boost on local control in ductal carcinoma in situ

Ductal carcinoma in situ of the breast is associated with low mortality rates, but local relapse is a matter of concern in this disease. Risk factors for local relapse include young age, close or positive margins, and tumor necrosis. Whole breast irradiation following breast-conserving surgery for ductal carcinoma in situ significantly reduces the risk of local relapse as compared to breast-conserving surgery alone. Studies point to similar outcomes between breast-conserving surgery plus radiotherapy and mastectomy, in the absence of extensive disease. A complementary boost to the surgical bed improves outcomes for patients with invasive breast cancer. However, the effect of this strategy has never been prospectively reported for ductal carcinoma in situ. Two randomized controlled trials assessing this issue are ongoing. This paper represents an update on available literature about radiotherapy for DCIS with a special focus on the role of a radiotherapy boost to the tumor bed.