Long-term risk of subsequent ipsilateral lesions after surgery with or without radiotherapy for ductal carcinoma in situ of the breast.

BACKGROUND: Radiotherapy (RT) following breast-conserving surgery (BCS) for ductal carcinoma in situ (DCIS) reduces ipsilateral breast event rates in clinical trials. This study assessed the impact of DCIS treatment on a 20-year risk of ipsilateral DCIS (iDCIS) and ipsilateral invasive breast cancer (iIBC) in a population-based cohort. METHODS: The cohort comprised all women diagnosed with DCIS in the Netherlands during 1989-2004 with follow-up until 2017. Cumulative incidence of iDCIS and iIBC following BCS and BCS + RT were assessed. Associations of DCIS treatment with iDCIS and iIBC risk were estimated in multivariable Cox models. RESULTS: The 20-year cumulative incidence of any ipsilateral breast event was 30.6% (95% confidence interval (CI): 28.9-32.6) after BCS compared to 18.2% (95% CI 16.3-20.3) following BCS + RT. Women treated with BCS compared to BCS + RT had higher risk of developing iDCIS and iIBC within 5 years after DCIS diagnosis (for iDCIS: hazard ratio (HR)age < 50 3.2 (95% CI 1.6-6.6); HRage ≥ 50 3.6 (95% CI 2.6-4.8) and for iIBC: HRage<50 2.1 (95% CI 1.4-3.2); HRage ≥ 50 4.3 (95% CI 3.0-6.0)). After 10 years, the risk of iDCIS and iIBC no longer differed for BCS versus BCS + RT (for iDCIS: HRage < 50 0.7 (95% CI 0.3-1.5); HRage ≥ 50 0.7 (95% CI 0.4-1.3) and for iIBC: HRage < 50 0.6 (95% CI 0.4-0.9); HRage ≥ 50 1.2 (95% CI 0.9-1.6)). CONCLUSION: RT is associated with lower iDCIS and iIBC risk up to 10 years after BCS, but this effect wanes thereafter.

Discordant Marker Expression Between Invasive Breast Carcinoma and Corresponding Synchronous and Preceding DCIS.

Ductal carcinoma in situ (DCIS) is considered a potential precursor of invasive breast carcinoma (IBC). Studies aiming to find markers involved in DCIS progression generally have compared characteristics of IBC lesions with those of adjacent synchronous DCIS lesions. The question remains whether synchronous DCIS and IBC comparisons are a good surrogate for primary DCIS and subsequent IBC. In this study, we compared both primary DCIS and synchronous DCIS with the associated IBC lesion, on the basis of immunohistochemical marker expression. Immunohistochemical analysis of ER, PR, HER2, p53, and cyclo-oxygenase 2 (COX-2) was performed for 143 primary DCIS and subsequent IBC lesions, including 81 IBC lesions with synchronous DCIS. Agreement between DCIS and IBC was assessed using kappa, and symmetry tests were performed to assess the pattern in marker conversion. The primary DCIS and subsequent IBC more often showed discordant marker expression than synchronous DCIS and IBC. Strikingly, 18 of 49 (36%) women with HER2-positive primary DCIS developed an HER2-negative IBC. Such a difference in HER2 expression was not observed when comparing synchronous DCIS and IBC. The frequency of discordant marker expression did not increase with longer time between primary DCIS and IBC. In conclusion, comparison of primary DCIS and subsequent IBC yields different results than a comparison of synchronous DCIS and IBC, in particular with regard to HER2 status. To gain more insight into the progression of DCIS to IBC, it is essential to focus on the relationship between primary DCIS and subsequent IBC, rather than comparing IBC with synchronous DCIS.

Clinicopathological Risk Factors for an Invasive Breast Cancer Recurrence after Ductal Carcinoma In Situ-A Nested Case-Control Study.

Purpose: Ductal carcinoma in situ (DCIS) is treated to prevent progression to invasive breast cancer. Yet, most lesions will never progress, implying that overtreatment exists. Therefore, we aimed to identify factors distinguishing harmless from potentially hazardous DCIS using a nested case-control study.Experimental Design: We conducted a case-control study nested in a population-based cohort of patients with DCIS treated with breast-conserving surgery (BCS) alone (N = 2,658) between 1989 and 2005. We compared clinical, pathologic, and IHC DCIS characteristics of 200 women who subsequently developed ipsilateral invasive breast cancer (iIBC; cases) and 474 women who did not (controls), in a matched setting. Median follow-up time was 12.0 years (interquartile range, 9.0-15.3). Conditional logistic regression models were used to assess associations of various factors with subsequent iIBC risk after primary DCIS.Results: High COX-2 protein expression showed the strongest association with subsequent iIBC [OR = 2.97; 95% confidence interval (95% CI), 1.72-5.10]. In addition, HER2 overexpression (OR = 1.56; 95% CI, 1.05-2.31) and presence of periductal fibrosis (OR = 1.44; 95% CI, 1.01-2.06) were associated with subsequent iIBC risk. Patients with HER2+/COX-2high DCIS had a 4-fold higher risk of subsequent iIBC (vs. HER2-/COX-2low DCIS), and an estimated 22.8% cumulative risk of developing subsequent iIBC at 15 years.Conclusions: With this unbiased study design and representative group of patients with DCIS treated by BCS alone, COX-2, HER2, and periductal fibrosis were revealed as promising markers predicting progression of DCIS into iIBC. Validation will be done in independent datasets. Ultimately, this will aid individual risk stratification of women with primary DCIS. Clin Cancer Res; 24(15); 3593-601. ©2018 AACR.

Cause-specific Mortality in a Population-based Cohort of 9799 Women Treated for Ductal Carcinoma In Situ.

OBJECTIVE: To assess cause-specific mortality in women treated for ductal carcinoma in situ (DCIS). BACKGROUND: From screening and treatment perspective, it is relevant to weigh the low breast cancer mortality after DCIS against mortality from other causes and expected mortality in the general population. METHODS: We conducted a population-based cohort study comprising 9799 Dutch women treated for primary DCIS between 1989 and 2004 and estimated standardized mortality ratios (SMRs). RESULTS: After a median follow up of 9.8 years, 1429 patients had died of whom 284 caused by breast cancer (2.9% of total cohort). DCIS patients <50 years experienced higher mortality compared with women in the general population (SMR 1.7; 95% confidence interval, CI: 1.4-2.0), whereas patients >50 had significantly lower mortality (SMR 0.9; 95% CI: 0.8-0.9). Overall, the risk of dying from general diseases and cancer other than breast cancer was lower than in the general population, whereas breast cancer mortality was increased. The SMR for breast cancer decreased from 7.5 (95% CI: 5.9-9.3) to 2.8 (95% CI: 2.4-3.2) for women aged <50 and >50 years, respectively. The cumulative breast cancer mortality 10 years after DCIS was 2.3% for women <50 years and 1.4% for women >50 years treated for DCIS between 1999 and 2004. CONCLUSIONS: DCIS patients >50 years had lower risk of dying from all causes combined compared with the general female population, which may reflect differences in health behavior. Women with DCIS had higher risk of dying from breast cancer than the general population, but absolute 10-year risks were low.

The method of detection of ductal carcinoma in situ has no therapeutic implications: results of a population-based cohort study.

BACKGROUND: Population screening with mammography has resulted in increased detection of ductal carcinoma in situ (DCIS). The aim of this population-based cohort study was to assess whether the method of detection should be considered when determining prognosis and treatment in women with DCIS. METHODS: This study includes 7042 women aged 49-75 years, who were surgically treated for primary DCIS between 1989 and 2004 in the Netherlands. We calculated cumulative incidences of ipsilateral and contralateral invasive breast cancer and all-cause mortality among women with screen-detected, interval, or non-screening-related DCIS, and assessed the association between method of detection and these outcomes, using multivariable Cox regression analyses. RESULTS: Compared with non-screening-related DCIS, women with screen-detected DCIS had a lower risk of developing ipsilateral invasive breast cancer (hazard ratio (HR) = 0.75, 95% CI = 0.59-0.96), but a similar risk of contralateral invasive breast cancer (HR = 0.86, 95% CI = 0.67-1.10). The absolute difference in risk of ipsilateral invasive breast cancer was 1% at 15 years. Screen detection was associated with lower all-cause mortality (HR = 0.85, 95% CI = 0.73-0.98); when we additionally accounted for the occurrence of invasive breast cancer the magnitude of this effect remained similar (HR = 0.86, 95% CI = 0.75-1.00). CONCLUSIONS: Screen detection was associated with lower risk of ipsilateral invasive breast cancer and all-cause mortality. However, the absolute difference in risk of ipsilateral invasive breast cancer was very low and the lower all-cause mortality associated with screen-detected and interval DCIS might be explained by a healthy-user effect. Therefore, our findings do not justify different treatment strategies for women with screen-detected, interval, or non-screening-related DCIS.

Finding the balance between over- and under-treatment of ductal carcinoma in situ (DCIS).

With the widespread adoption of population-based breast cancer screening, ductal carcinoma in situ (DCIS) has come to represent 20-25% of all breast neoplastic lesions diagnosed. Current treatment aims at preventing invasive breast cancer, but the majority of DCIS lesions will never progress to invasive disease. Still, DCIS is treated by surgical excision, followed by radiotherapy as part of breast conserving treatment, and/or endocrine therapy. This implies over-treatment of the majority of DCIS, as less than 1% of DCIS patients will go on to develop invasive breast cancer annually. If we are able to identify which DCIS is likely to progress or recur as invasive breast cancer and which DCIS would remain indolent, we can treat the first group intensively, while sparing the second group from such unnecessary treatment (surgery, radiotherapy, endocrine therapy) preserving the quality of life of these women. This review summarizes our current knowledge on DCIS and the risks involved regarding progression into invasive breast cancer. It also shows current knowledge gaps, areas where profound research is highly necessary for women with DCIS to prevent their over-treatment in case of a harmless DCIS, but provide optimal treatment for potentially hazardous DCIS.

Subsequent risk of ipsilateral and contralateral invasive breast cancer after treatment for ductal carcinoma in situ: incidence and the effect of radiotherapy in a population-based cohort of 10,090 women.

PURPOSE: To assess the effect of different treatment strategies on the risk of subsequent invasive breast cancer (IBC) in women diagnosed with ductal carcinoma in situ (DCIS). METHODS: Up to 15-year cumulative incidences of ipsilateral IBC (iIBC) and contralateral IBC (cIBC) were assessed among a population-based cohort of 10,090 women treated for DCIS in the Netherlands between 1989 and 2004. Multivariable Cox regression analyses were used to evaluate associations of treatment with iIBC risk. RESULTS: Fifteen years after DCIS diagnosis, cumulative incidence of iIBC was 1.9 % after mastectomy, 8.8 % after BCS+RT, and 15.4 % after BCS alone. Patients treated with BCS alone had a higher iIBC risk than those treated with BCS+RT during the first 5 years after treatment. This difference was less pronounced for patients <50 years [hazard ratio (HR) 2.11, 95 % confidence interval (CI) 1.35-3.29 for women <50, and HR 4.44, 95 % CI 3.11-6.36 for women ≥50, P interaction  < 0.0001]. Beyond 5 years of follow-up, iIBC risk did not differ between patients treated with BCS+RT or BCS alone for women <50. Cumulative incidence of cIBC at 15 years was 6.4 %, compared to 3.4 % in the general population. CONCLUSIONS: We report an interaction of treatment with age and follow-up period on iIBC risk, indicating that the benefit of RT seems to be smaller among younger women, and stressing the importance of clinical studies with long follow-up. Finally, the low cIBC risk does not justify contralateral prophylactic mastectomies for many women with unilateral DCIS.

[Ductal carcinoma in situ: the balance between over- and undertreatment]. / Ductaal carcinoma in situ: de balans tussen over- en onderbehandeling.

Since population-based breast cancer screening was implemented in the Netherlands, the incidence of Ductal Carcinoma In Situ of the breast, regarded as a non-obligate precursor lesion of breast cancer, has strongly increased. However, the incidence of invasive breast cancer has not decreased. This suggests that a percentage of all the DCIS lesions would never have become symptomatic if no screening was performed. This phenomenon is known as 'overdiagnosis'. Nonetheless, almost all DCIS lesions are managed surgically, often followed by radiotherapy in those having breast-conserving treatment, to avoid potential progression to breast cancer. To prevent potential over- or undertreatment, further studies are required to distinguish low from high risk DCIS. Ultimately this could help avoid non-beneficial intensive treatment for women with low risk DCIS.

Feasibility of a prospective, randomised, open-label, international multicentre, phase III, non-inferiority trial to assess the safety of active surveillance for low risk ductal carcinoma in situ - The LORD study.

BACKGROUND: The current debate on overdiagnosis and overtreatment of screen-detected ductal carcinoma in situ (DCIS) urges the need for prospective studies to address this issue. A substantial number of DCIS lesions will never form a health hazard, particularly if it concerns non- to slow-growing low-grade DCIS. The LORD study aims to evaluate the safety of active surveillance in women with low-risk DCIS. DESIGN: This is a randomised, international multicentre, open-label, phase III non-inferiority trial, led by the Dutch Breast Cancer Research Group (BOOG 2014-04) and the European Organization for Research and Treatment of Cancer (EORTC-BCG 1401). Standard treatment will be compared to active surveillance in 1240 women aged ⩾ 45 years with asymptomatic, screen-detected, pure low-grade DCIS based on vacuum-assisted biopsies of microcalcifications only. Both study arms will be monitored with annual digital mammography for a period of 10 years. The primary end-point is 10-year ipsilateral invasive breast cancer free percentage. Secondary end-points include patient reported outcomes, diagnostic biopsy rate during follow-up, ipsilateral mastectomy rate and translational research. FEASIBILITY: To explore interest in and feasibility of the LORD study we conducted a survey among EORTC and BOOG centres. A vast majority of EORTC and BOOG responding centres expressed interest in participation in the LORD study. The proposed study design is endorsed by nearly all centres.

Does the pretreatment tumor sampling location correspond with metabolic activity on 18F-FDG PET/CT in breast cancer patients scheduled for neoadjuvant chemotherapy?

PURPOSE: To define the correlation between the core biopsy location and the area with highest metabolic activity on 18F-FDG PET/CT in stage II-III breast cancer patients before neoadjuvant chemotherapy. Also, we would like to select a subgroup of patients in which PET/CT information may optimize tumor sampling. METHODS: A PET/CT in prone position was acquired in 199 patients with 203 tumors. The distance and relative difference in standardized uptake value (SUV) between core biopsy localization (indicated by a marker) and area with highest degree of FDG uptake were evaluated. A distance ≥ 2 cm and a relative difference in SUV ≥ 25% were considered clinically relevant and a combination of both was defined as non-correspondence. Non-correspondence for different tumor characteristics (TNM stage, lesion morphology on MRI and PET/CT, histology, subtype, grade, and Ki-67) was assessed. RESULTS: Non-correspondence was found in 28 (14%) of 203 tumors. Non-correspondence was significantly associated with T-stage, lesion morphology on MRI and PET/CT, tumor diameter, and histologic type. It was more often seen in tumors with a higher T-stage (p = 0.028), diffuse (non-mass) and multifocal tumors on MRI (p = 0.001), diffuse and multifocal tumors on PET/CT (p<0.001), tumors >3 cm (p<0.001), and lobular carcinomas (p<0.001). No association was found with other features. CONCLUSION: Non-correspondence between the core biopsy location and area with highest FDG uptake is regularly seen in stage II-III breast cancer patients. PET/CT information and possibly FDG-guided biopsies are most likely to improve pretreatment tumor sampling in tumors >3 cm, lobular carcinomas, and diffuse and multifocal tumors.

A practical approach to manage additional lesions at preoperative breast MRI in patients eligible for breast conserving therapy: results.

The aim of this prospective study was to evaluate the efficacy of directives, established to handle additional lesions at preoperative contrast-enhanced magnetic resonance imaging (MRI). Six-hundred-and-ninety consecutive patients with pathology-proven breast cancer planned for BCT based on clinical examination and conventional imaging underwent preoperative breast MRI. The incidence of additional lesions detected at MRI and impact on management were evaluated. Additional findings were pathology-proven or considered benign by follow-up. Findings for which no pathology proof was available prior to surgery, were defined as Unidentified Breast Objects (UBOs). Patients with multicentric or contralateral UBOs underwent BCT as planned with annual follow-up. Multifocal UBOs in the vicinity of the index cancer were excised with wider local margins. Preoperative MRI detected 141 additional lesions in 121 patients (17.5%). Of these lesions, 44.0% were proven malignant. Additional findings classified as UBOs were found in 81 patients (11.7%). None of the UBOs outside the primary tumour region resulted in malignant disease at follow-up after BCT (mean follow-up time: 57.1 months). However, most multifocal UBOs (in the vicinity of the primary) were malignant (77.5%). The strategy to pursue BCT with larger wide-local excisions for multifocal UBOs and to follow-up multicentric and contralateral UBOs with conventional imaging is effective to exclude malignancy at follow-up. After second-look targeted ultrasound has been performed, MRI-guided biopsy of BIRADS-3 multicentric and contralateral additional findings may have limited complementary clinical value.