Ductal Carcinoma In Situ of the Breast With Close or Focally Involved Margins Following Breast-Conserving Surgery: Treatment With Reexcision or Radiotherapy With Increased Dosage

Tailored radiation dose according to margin width for patients with ductal carcinoma in situ after breast-conserving surgery

A 2 mm resection margin is considered adequate for ductal carcinoma in situ (DCIS). We assessed the effectiveness of a tailored radiation dose for margins < 2 mm and the appropriate margin width for high-risk DCIS. We retrospectively evaluated 137 patients who received adjuvant radiotherapy after breast-conserving surgery for DCIS between 2013 and 2019. The patients were divided into three- positive, close (< 2 mm), and negative (≥ 2 mm) margin groups. Radiation dose to the tumor bed in equivalent dose in 2 Gy fractions were a median of 66.25 Gy, 61.81 Gy, and 59.75 Gy for positive, close, and negative margin groups, respectively. During a median follow-up of 58 months, the crude rates of local recurrence were 15.0%, 6.7%, and 4.6% in the positive, close, and negative margin groups, respectively. The positive margin group had a significantly lower 5-year local recurrence-free survival (LRFS) rate compared to the close and negative margin groups in propensity-weighted log-rank analysis (84.82%, 93.27%, and 93.20%, respectively; p = 0.008). The difference in 5-year LRFS between patients with the high- and non-high-grade tumors decreased as the margin width increased (80.4% vs. 100.0% for margin ≥ 2 mm, p < 0.001; 92.3% vs. 100.0% for margin ≥ 6 mm, p = 0.123). With the radiation dose tailored for margin widths, positive margins were associated with poorer local control than negative margins, whereas close margins were not. Widely clear margins (≥ 2 mm) were related to favorable local control for high-grade DCIS.

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.

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.

Educational Case: Ductal Carcinoma In Situ (DCIS)

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, see http://journals.sagepub.com/doi/10.1177/2374289517715040.¹

[Ductal carcinoma in situ in 2019: Diagnosis, treatment, prognosis]

Ductal carcinoma in situ (DCIS) currently represents up to 15% of the newly diagnosed breast cancers, and are almost always detected by microcalcifications. Global prognosis is good (3% of 15-year specific mortality) but invasive local recurrences (LR) can lead to metastasis in 12-15% of the cases. Breast conserving surgery with whole breast irradiation is the main treatment (reducing LR by 50%), but mastectomy (with or without reconstruction) is performed in about 30% of the cases due to wide lesion size and/or multicentricity. The role of tamoxifen remains unclear. Axillary dissection is needless but sentinel node biopsy is proposed in case of micro-invasion suspicion (large lesions with high grade). The main factors of LR are young age (≤40 years) incomplete excision, and high nuclear grade with comedonecrosis. Several studies on "therapeutic descalation" are still ongoing in order to identify the "low risk" DCIS (about 10% of the cases) in which radiotherapy could be safely omitted.

Role of boost radiotherapy for local control of pure ductal carcinoma in situ after breast-conserving surgery: a multicenter, retrospective study of 622 patients

PURPOSE

To evaluate the effect of boost radiotherapy on ipsilateral breast tumor recurrence (IBTR) for ductal carcinoma in situ (DCIS) after breast-conserving surgery and whole breast radiotherapy (WBRT) with or without boost.

METHODS AND MATERIALS

Retrospective, multicentre study of 622 patients (624 tumors) diagnosed with pure DCIS from 1993-2011.

RESULTS

Most tumors (377/624; 60.4%) received a boost. At a median follow-up of 8.8 years, IBTR occurred in 64 cases (10.3%). A higher percentage of patients with risk factors for IBTR received a boost (p < 0.05). Boost was not associated with lower rates of IBTR than WBRT alone (HR 0.75, 95% CI 0.42-1.35). On the univariate analyses, IBTR was significantly associated with tumor size (11-20 mm, HR 2.32, 95% CI 1.27-4.24; and > 20 mm, HR 2.10, 95% CI 1.14-3.88), re-excision (HR 1.76, 95% CI 1.04-2.96), and tamoxifen (HR 2.03, 95% CI 1.12-3.70). Boost dose > 16 Gy had a protective effect (HR 0.39, 95% CI 0.187-0.824). Multivariate analyses confirmed the independent associations between IBTR and 11-20 mm (p = 0.02) and > 20 mm (p = 0.009) tumours, and re-excision (p = 0.006). On the margin-stratified multivariate analysis, tamoxifen was a poor prognostic factor in the close/positive margin subgroup (HR 4.28 95% CI 1.23-14.88), while the highest boost dose ( > 16 Gy) had a significant positive effect (HR 0.34, 95% CI 0.13-0.86) in the negative margin subgroup.

CONCLUSIONS

Radiotherapy boost did not improve the risk of IBTR. Boost radiotherapy was more common in patients with high-risk disease. Tumor size and re-excision were significant independent prognostic factors.

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.

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.

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.

Importance of Surgical Margin Status in Ductal Carcinoma In Situ

BACKGROUND

The purpose of the study was to identify the effect of final surgical margin (SM) status and re-excision on outcomes in patients with ductal carcinoma in situ (DCIS) who underwent breast conservation therapy (BCT).

PATIENTS AND METHODS

The study population consisted of women diagnosed with DCIS who underwent BCT between 1989 and 2014. All women received adjuvant whole breast radiation and a boost. The primary end point was local control (LC). Final SMs were defined according to margin width: negative SM was defined as > 2 mm, close SM was defined as > 0 to ≤ 2 mm, and a positive SM was defined as tumor on ink. The Cox proportional hazards model was used to determine predictors of outcomes on multivariable analysis. Actuarial incidence of LC was estimated using the Kaplan-Meier method.

RESULTS

A total of 498 patients were included; 400 patients had a final negative SM, 87 had a close SM, and 11 had a positive SM. A total of 172 patients received adjuvant hormonal therapy, 265 patients required ≥ 1 re-excision. Patients with positive or close SMs were more likely to receive a radiation dose > 60 Gy (P < .001) and undergo re-excision (P < .01). The 10-year LC rates were not significantly different between patients with a negative (93.5%), close (91.8%), or positive (100%) SM (P = .57). There was no difference in LC in patients who underwent re-excision for initial close or positive SMs (P = .55).

CONCLUSION

This single-institution experience showed that risks of local recurrence remain poorly characterized. Re-excision and whole breast radiation with boost resulted in excellent LC for women with DCIS. Trials aimed at personalized deintensified local therapy are warranted.

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.

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.

Outcomes in patients treated with mastectomy for ductal carcinoma in situ

PURPOSE

To examine, in a large, population-based cohort of women, the risk factors for recurrence after mastectomy for pure ductal carcinoma in situ (DCIS) and to identify which patients may benefit from postmastectomy radiation therapy.

METHODS AND MATERIALS

Data were analyzed for 637 subjects with pure DCIS, diagnosed between January 1990 and December 1999, treated initially with mastectomy. Locoregional relapse (LRR), breast cancer-specific survival, and overall survival were described using the Kaplan-Meier method. Reported risk factors for LRR (age, margins, size, Van Nuys Prognostic Index, grade, necrosis, and histologic subtype) were analyzed by univariate (log-rank) and multivariate (Cox modeling) methods.

RESULTS

Median follow-up was 12.0 years. Characteristics of the cohort were median age 55 years, 8.6% aged ≤ 40 years, 30.5% tumors >4 cm, 42.5% grade 3 histology, 37.7% multifocal disease, and 4.9% positive margins. At 10 years, LRR was 1.0%, breast cancer-specific survival was 98.0%, and overall survival was 90.3%. All recurrences (n=12) involved ipsilateral chest wall disease, with the majority being invasive disease (11 of 12). None of the 12 patients with recurrence died of breast cancer; all were successfully salvaged (median follow-up of 4.4 years). Ten-year LRR was higher with age ≤ 40 years (7.5% vs 1.5%; P=.003).

CONCLUSION

Mastectomy provides excellent locoregional control for DCIS. Routine use of postmastectomy radiation therapy is not justified. Young age (≤40 years) predicts slightly higher LRR, but possibly owing to the small number of cases with multiple risk factors for relapse, a subgroup with a high risk of LRR (ie, approximately 15%) was not identified.

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.

The management of ductal intraepithelial neoplasia (DIN): open controversies and guidelines of the Istituto Europeo di Oncologia (IEO), Milan, Italy

The management of ductal intraepithelial neoplasia (DIN) has substantially changed over the past 30 years, as its incidence has increased (from 2-3% to more than 20%), mainly due to the widespread use of mammography screening. This article describes not only the more widespread theoretical concepts on DIN but also the differences in the practical applications of the theory between different countries, different oncology specialists, and different cancer centers. Papers related to the international multicentre-randomized trials and retrospective studies were analyzed. We include articles and papers published between 1993 and 2010 related to patients with DIN, and abstracts and reports from MEDLINE and other sources were indentified. The standard of care for DIN consists of (a) breast conservative surgery (mastectomy is still indicated in large lesions--masses or microcalcifications--in about 30% of cases); (b) radiotherapy (RT) after conservative surgery, and (c) medical treatment in estrogen receptors-positive patients. However, most studies have shown significant differences between theory and practical application. Moreover, there are differences regarding (a) the indications of sentinel lymph node biopsy, (b) the definition and identification of low-risk DIN subgroups that can avoid RT and tamoxifen, and (c) the research into new alternative drugs in adjuvant medical therapy. A general agreement on the best management of DIN does not exist as yet. New large trials are needed in order to define the best management of DIN patients which is (in most respects) still complex and controversial.

Local and systemic outcomes in DCIS based on tumor and patient characteristics: the radiation oncologist's perspective

Four randomized clinical trials have shown unanimously the benefit of 50 Gy whole-breast radiotherapy in breast-conserving therapy (BCT) for ductal carcinoma in situ (DCIS). The risk of both DCIS and invasive local recurrence is reduced with about 50%, and this effect is similar for all clinical and histological subgroups analyzed. Younger age and involved margin status are the most important factors for an increased risk of local recurrence. In these subgroups, even with radiotherapy, the observed local recurrence rates are more than 20% at 10 years, which is considerably higher than reported local recurrence rates after BCT for invasive breast cancer. The optimal radiotherapy dose in BCT for DCIS has yet to be established. Also, at present, a subgroup of lesions in which the recurrence rate is so low that radiotherapy can be safely omitted has not yet been identified.