Seizing the moment: The time for harnessing electronic patient-reported outcome measures for enhanced and sustainable metastatic breast cancer care is now.

The sustainability of healthcare systems is under pressure. Unlike care for many other chronic diseases, cancer care has yet to empower patients in effectively self-managing both the medical and emotional consequences of their condition, including adapting to changes in lifestyle and work, which is essential to achieve optimal health and recovery. Although proposed as a potential solution for sustainable healthcare and support for optimal health and recovery already decades ago, practical implementation of digital care lags behind. We believe electronic patient reported outcome measures (ePROMs) could play an important role in creating sustainable healthcare, both to guide complex treatment pathways and to empower survivors to self-manage consequences of diagnosis and treatment. That is, ePROMs can be used for screening and monitoring of symptoms, but also for treatment decision-making and to facilitate communication about quality of life. We therefore see opportunities for improvements in quality of care, quality of life, and survival of cancer patients, as well as research opportunities, as ePROMs collection can lead to better understanding of care needs. The '10 Actions for Change report' of the Advanced Breast Cancer Global Alliance stresses a critical need for improvement of care for metastatic breast cancer (MBC) patients. We therefore in this paper focus on MBC care and research.

Updated normative data for the EORTC QLQ-C30 in the general Dutch population by age and sex: a cross-sectional panel research study.

PURPOSE: The European Organisation for Research and Treatment of Cancer (EORTC) quality of life core questionnaire (QLQ-C30) is a validated and widely-used Patient-Reported Outcome Measure for measuring the health-related quality of life (HRQoL) of cancer patients. To facilitate interpretation of results obtained in studies using the EORTC QLQ-C30, we generated normative data for the Dutch general population, stratified by age and sex. METHODS: Dutch participants were selected from a larger cross-sectional online panel research study collecting EORTC QLQ-C30 general population normative data across 15 countries. EORTC QLQ-C30 raw scores based on a 4-point response scale were transformed to linear scores ranging from 0 to 100. Transformed scores were weighted based on the United Nations population distribution statistics and presented by age and sex/age. Differences in scale scores of ≥ 10 points in HRQoL were applied to indicate clinical relevance. RESULTS: One thousand respondents completed the online survey. Stratified by age, clinically meaningful differences were observed, with worse physical functioning scores and better emotional functioning scores with increased age. Symptom scores remained stable across age groups, except for small age differences observed for fatigue, nausea/vomiting, diarrhoea, and financial difficulties. Stratified by sex/age, men generally scored better for both functioning and symptoms. However, these differences were not clinically meaningful. CONCLUSIONS: These updated normative EORTC QLQ-C30 for the Dutch general population can be used to better interpret HRQoL data obtained from Dutch cancer patients. Being part of a larger international study, these data can further be used for inter-country comparisons in multi-national studies.

Selecting a PRO-CTCAE-based subset for patient-reported symptom monitoring in prostate cancer patients: a modified Delphi procedure.

BACKGROUND: Clinician-based reporting of adverse events leads to underreporting and underestimation of the impact of adverse events on prostate cancer patients. Therefore, interest has grown in capturing adverse events directly from patients using the Patient-Reported Outcomes (PROs) version of the Common Terminology Criteria for Adverse Events (CTCAE). We aimed to develop a standardized PRO-CTCAE subset tailored to adverse event monitoring in prostate cancer patients. MATERIALS AND METHODS: We used a mixed-method approach based on the 'phase I guideline for developing questionnaire modules' by the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life group, including a literature review, and interviews with patients (n = 30) and health care providers (HCPs, n = 16). A modified Delphi procedure was carried out to reach consensus on the final subset selected from the complete PRO-CTCAE item library. RESULTS: Fourteen multidisciplinary HCPs and 12 patients participated in the Delphi rounds. Ninety percent agreed on the final subset, consisting of: 'ability to achieve and maintain erection', 'decreased libido', 'inability to reach orgasm', 'urinary frequency', 'urinary urgency', 'urinary incontinence', 'painful urination', 'fecal incontinence', 'fatigue', 'hot flashes', 'feeling discouraged', 'sadness', and 'concentration'. From 16 articles identified in the literature review, the following adverse events for which no PRO-CTCAE items are available, were included to the recommendation section: 'nocturia', 'blood and/or mucus in stool', 'hemorrhoids', 'hematuria', 'cystitis', 'neuropathy', and 'proctitis'. CONCLUSIONS: The obtained PRO-CTCAE-subset can be used for multidisciplinary adverse event monitoring in prostate cancer care. The described method may guide development of future PRO-CTCAE subsets.

International development of a patient-centered core outcome set for assessing health-related quality of life in metastatic breast cancer patients.

PURPOSE: For patients living with metastatic breast cancer (MBC), achieving best possible health-related quality of life, along with maximizing survival, is vital. Yet, we have no systemic way to determine if we achieve these goals. A Core Outcome Set (COS) that allows standardized measurement of outcomes important to patients, but also promotes discussing these outcomes during clinical encounters, is long overdue. METHODS: An international expert group (EG) of patient advocates, researchers, medical specialists, nurse specialists, and pharmaceutical industry representatives (n = 17) reviewed a list of relevant outcomes retrieved from the literature. A broader group (n = 141: patients/patient advocates (n = 45), health care professionals/researchers (n = 64), pharmaceutical industry representatives (n = 28), and health authority representatives (n = 4)) participated in a modified Delphi procedure, scoring the relevance of outcomes in two survey rounds. The EG finalized the COS in a consensus meeting. RESULTS: The final MBC COS includes 101 variables about: (1) health-related quality of life (HRQoL, n = 26) and adverse events (n = 24); (2) baseline patient characteristics (n = 9); and (3) clinical variables (n = 42). Many outcome that cover aspects of HRQoL relevant to MBC patients are included, e.g. daily functioning (including ability to work), psychosocial/emotional functioning, sexual functioning, and relationship with the medical team. CONCLUSION: The COS developed in this study contains important administrative data, clinical records, and clinician-reported measures that captures the impact of cancer. The COS is important for standardization of clinical research and implementation in daily practice and has received accreditation by the International Consortium for Health Outcomes Measurement (ICHOM).

Functional outcomes rather than complications predict poor health-related quality of life at 6 months after robot-assisted radical prostatectomy.

The objective is to evaluate the effect of robot-assisted radical prostatectomy (RARP)-related postoperative complications on the 6-month postoperative health-related quality of life (HRQoL). A total of 1008 patients underwent a RARP with or without pelvic lymph node dissection (PLND) between 2012 and 2020 and were invited to complete questionnaires about HRQoL and functional outcomes (urinary incontinence (UI), erectile dysfunction (ED) and urinary complaints (UC)) before and 6 months after RARP. Patient characteristics and postoperative complications up to 90 days after surgery were prospectively recorded. Associations between complications and HRQoL/functional outcomes were assessed by multivariate linear regression analyses. In total, 528 patients (52.4%) were included in the analyses. Complications occurred in 165/528 (31.3%) patients, of which 30/165 (18.2%) had a Clavien-Dindo ≥ III complication. In multivariate regression analyses, postoperative complications were not significantly associated with postoperative HRQoL, UI and ED (p = 0.73, p = 0.72 and p = 0.95, respectively), but were significantly associated with a minor increase in UC (ß = 1.7, p < 0.001). More specifically, infectious and urological complications were significantly associated with an increase in UC (ß = 1.9, p < 0.001 and ß = 0.9, p = 0.004, respectively). The presence of UTI, in particular, was significantly associated with this minor increase (ß = 1.5, p = 0.002). Functional outcomes were all significantly associated with the HRQoL at 6 months postoperatively. No significant associations were found between postoperative complications and HRQoL at 6 months after RARP. However, worse functional outcomes were associated with a worse HRQoL at 6 months postoperatively. In addition, postoperative infectious and urological complications were significantly associated with a minor increase in UC.

Predictors of delayed breast reconstruction in the Netherlands: a 5-year follow-up study in stage I-III breast cancer patients.

PURPOSE: Delayed breast reconstruction (DBR) is a valid option for postmastectomy breast cancer patients who have a desire for breast reconstruction but are not considered suitable for immediate breast reconstruction (IBR). The objective of this study was to investigate the clinical practice and predictors of the use of DBR in the Netherlands. METHODS: Stage I-III breast cancer patients diagnosed from January to March 2012 and treated with mastectomy were selected from the Netherlands Cancer Registry. Routinely collected patient, tumor, treatment and hospital characteristics were complemented with data about DBR up to 2018. Multivariable logistic regression analyses were performed to identify factors independently associated with postmastectomy DBR. Factors associated with time to DBR were identified through Cox regression analyses. RESULTS: Of all patients who underwent mastectomy (n = 1,415), 10.2% underwent DBR. DBR patients more often received autologous reconstruction compared to IBR patients (37.5% vs 6.2%, p < 0.001). Age below 50 years (age < 35 OR 15.55, age 35-49 OR 4.18) and neoadjuvant and adjuvant chemotherapy (OR 2.59 and OR 2.83, respectively) were significantly associated with DBR. Mean time to DBR was 2.4 years [range 1-6 years]. Time to DBR was significantly associated with age < 35 years (HR 2.22), and a high hospital volume (HR 1.87). DISCUSSION: The use of DBR after mastectomy could not be fully explained by age below 50 years, chemotherapy, and hospital volume. Treatment with radiotherapy and adjuvant chemotherapy increased time to DBR. More information about patient preferences is needed to understand the use and timing of reconstruction.

The added value of immediate breast reconstruction to health-related quality of life of breast cancer patients.

BACKGROUND: Postmastectomy immediate breast reconstruction (IBR) may improve the quality of life (QoL) of breast cancer patients. Guidelines recommend to discuss the option IBR with all patients undergoing mastectomy. However, substantial hospital variation in IBR-rates was previously observed in the Netherlands, influenced by patient, tumour and hospital factors and clinicians' believes. Information provision about IBR may have a positive effect on receiving IBR and therefore QoL. This study investigated patient-reported QoL of patients treated with mastectomy with and without IBR. METHODS: An online survey, encompassing the validated BREAST-Q questionnaire, was distributed to a representative sample of 1218 breast cancer patients treated with mastectomy. BREAST-Q scores were compared between patients who had undergone mastectomy either with or without IBR. RESULTS: A total of 445 patients were included for analyses: 281 patients with and 164 without IBR. Patients who had received IBR showed significantly higher BREAST-Q scores on "psychosocial well-being" (75 versus 67, p < 0.001), "sexual well-being" (62 versus 52, p < 0.001) and "physical well-being" (77 versus 74, p = 0.021) compared to patients without IBR. No statistically significant difference was found for "satisfaction with breasts" (64 versus 62, p = 0.21). Similar results were found after multivariate regression analyses, revealing IBR to be an independent factor for a better patient-reported QoL. CONCLUSIONS: Patients diagnosed with breast cancer with IBR following mastectomy report a better QoL on important psychosocial, sexual and physical well-being domains. This further supports the recommendation to discuss the option of IBR with all patients with an indication for mastectomy and to enable shared decision-making.

Effect of omission of surgery on survival in patients aged 80 years and older with early-stage hormone receptor-positive breast cancer.

BACKGROUND: Surgery is increasingly being omitted in older patients with operable breast cancer in the Netherlands. Although omission of surgery can be considered in frail older patients, it may lead to inferior outcomes in non-frail patients. Therefore, the aim of this study was to evaluate the effect of omission of surgery on relative and overall survival in older patients with operable breast cancer. METHODS: Patients aged 80 years or older diagnosed with stage I-II hormone receptor-positive breast cancer between 2003 and 2009 were selected from the Netherlands Cancer Registry. An instrumental variable approach was applied to minimize confounding, using hospital variation in rate of primary surgery. Relative and overall survival was compared between patients treated in hospitals with different rates of surgery. RESULTS: Overall, 6464 patients were included. Relative survival was lower for patients treated in hospitals with lower compared with higher surgical rates (90·2 versus 92·4 per cent respectively after 5 years; 71·6 versus 88·2 per cent after 10 years). The relative excess risk for patients treated in hospitals with lower surgical rates was 2·00 (95 per cent c.i. 1·17 to 3·40). Overall survival rates were also lower among patients treated in hospitals with lower compared with higher surgical rates (48·3 versus 51·3 per cent after 5 years; 15·0 versus 19·7 per cent after 10 years respectively; adjusted hazard ratio 1·07, 95 per cent c.i. 1·00 to 1·14). CONCLUSION: Omission of surgery is associated with worse relative and overall survival in patients aged 80 years or more with stage I-II hormone receptor-positive breast cancer. Future research should focus on the effect on quality of life and physical functioning.

ANTECEDENTES: En los Países Bajos cada vez es más frecuente descartar la cirugía en pacientes mayores con cáncer de mama operable. Aunque la omisión de la cirugía puede ser adecuada en pacientes mayores frágiles, ello puede determinar peores resultados en pacientes no frágiles. Por tanto, el objetivo de este estudio fue evaluar el efecto de omitir la cirugía en la supervivencia relativa y en la supervivencia global en pacientes mayores con cáncer de mama operable. MÉTODOS: A partir del Registro de Cáncer de los Países Bajos se seleccionaron las pacientes de ≥ 80 años de edad diagnosticadas de cáncer de mama entre 2003-2009 en estadios 1-2 y con receptores hormonales positivos. Se aplicó un método de variables instrumentales para minimizar los factores de confusión utilizando la tasa de variación hospitalaria de la cirugía primaria. Se compararon las supervivencias relativa y global de las pacientes tratadas en hospitales con diferentes tasas de cirugía. RESULTADOS: Se incluyeron 6.464 pacientes. La supervivencia relativa fue menor en las pacientes tratadas en hospitales con tasas quirúrgicas más bajas en comparación con las tratadas en hospitales con tasas altas (90,2% versus 92,4% a los 5 años y 71,6% versus 88,2% a los 10 años, respectivamente). El exceso de riesgo relativo para las pacientes tratadas en hospitales con tasas quirúrgicas más bajas fue de 2,00 (i.c. del 95% 1,17-3,40). La supervivencia global también fue menor para las pacientes tratadas en hospitales con tasas quirúrgicas más bajas en comparación con las más altas (48,3% versus 51,3% a los 5 años y 15,0% versus 19,7% a los 10 años, respectivamente, cociente de riesgos instantáneos, hazard ratio, HR, ajustado 1,07) i.c. del 95% 1,00-1,14)). CONCLUSIÓN: Omitir la cirugía se asocia con una peor supervivencia relativa y global en pacientes de ≥ 80 años con cáncer de mama en estadios 1-2 y receptores hormonales positivos. Las investigaciones futuras deberían centrarse en el efecto de este enfoque en la calidad de vida y la funcionalidad física.

The impact of health symptoms on health-related quality of life in early-stage breast cancer survivors.

PURPOSE: In breast cancer patients, treatment-related health symptoms can occur that may affect their health-related quality of life (HRQoL). This study aimed to determine the impact of health symptoms on HRQoL in breast cancer patients up to 5 years after diagnosis. METHODS: Females surgically treated for early-stage breast cancer diagnosed between 2012 and 2016 (n = 876) were selected from the Netherlands Cancer Registry and invited for a survey about current health symptoms ('Symptoms and Perceptions questionnaire', SaP) and HRQoL ('EORTC-QLQ-C30'). From the latter, functioning and global health were included. Mean scores were compared to norm population scores (T test). Multivariable linear regression analyses were performed to determine the association between health symptoms and global health and functioning. RESULTS: 404 patients (46%) responded. The median age was 62.2 ± 10.9 years. Respondents had significantly lower mean scores for role, cognitive, emotional, and social functioning than the general population. The most frequently reported health symptoms were musculoskeletal (including pain/complaints in lower/upper extremities/back/neck; 71%) and central nervous system symptoms (including concentration impairment, dizziness, neuralgia; 66%), and fatigue (63%). While most symptoms affected functioning, irrespective of time since diagnosis, especially fatigue, musculoskeletal, central nervous system, and gastrointestinal symptoms were significantly associated (p < 0.05) with lower functioning. CONCLUSIONS: The majority of health symptoms that occur after breast cancer treatment were associated with lower functioning of patients in daily life. This paper urges healthcare providers to support breast cancer patients in alleviating or coping with health symptoms, even years after end of treatment, to improve their functioning.

Patient-reported health problems and healthcare use after treatment for early-stage breast cancer.

BACKGROUND: A clear picture of treatment-related health problems following breast cancer treatment is useful in anticipating the informational and other needs of patients during follow-up. This study aimed to identify treatment-related health problems in breast cancer patients up to five years after diagnosis. Secondly, the use of care associated with these health problems was identified. METHODS: 876 surgically-treated female patients diagnosed between 2012 and 2016 with early-stage breast cancer were asked to complete an online survey about their current health problems and use of care. Multivariate logistic regression analyses were applied to determine the effect of patient and treatment characteristics on health problems. RESULTS: 404 patients responded (46%). The median age was 62.0 years (SD:10.9). Apart from breast surgery, patients had been treated with radiotherapy (72%), chemotherapy (49%), anti-hormonal therapy (57%), and axillary dissection (21%). Ninety-three percent experienced one or more health problems. Over 50% of respondents experienced fatigue, psychological problems, and health problems regarding the breast, and/or musculoskeletal, central nervous, and reproductive system. Treatment with chemotherapy was significantly associated (p < 0.05) with an increased risk of health problems, respectively fatigue (OR:2.00), respiratory (OR:1.81), gastrointestinal (OR:1.87), central nervous (OR:3.40), and skin problems (OR:2.62). Use of healthcare for one or more health problems was reported by 64% of respondents. DISCUSSION: Almost all patients experienced health problems up to five years after breast cancer diagnosis, with a range of complaints that were consistently present over time. Factors associated with the development of health problems are useful for better informing patients beforehand and targeting follow-up care.

Current decisions on neoadjuvant chemotherapy for early breast cancer: Experts' experiences in the Netherlands.

PURPOSE: To evaluate the opinion of surgical and medical oncologists on neoadjuvant chemotherapy (NAC) for early breast cancer. METHODS: Surgical and medical oncologists (N = 292) participating in breast cancer care in the Netherlands were invited for a 20-question survey on the influence of patient, disease, and management related factors on their decisions towards NAC. RESULTS: A total of 138 surgical and medical oncologists from 64 out of 89 different Dutch hospitals completed the survey. NAC was recommended for locally advanced breast cancer (94%) and for downstaging to enable breast conserving surgery (BCS) (75%). Despite willingness to downstage, 64% of clinicians routinely recommended NAC when systemic therapy was indicated preoperatively. Reported reasons to refrain from NAC are comorbidities (68%), age >70 years (52%), and WHO-performance status ≥2 (93%). Opinions on NAC and surgical management were inconclusive; while 75% recommends NAC to enable BCS, some stated that BCS after NAC increases the risk of a non-radical resection (21%), surgical complications (9%) and recurrence of disease (5%). CONCLUSION: This article emphasizes the need for more consensus among specialists on the indications for NAC in early BC patients. Unambiguous and evidence-based treatment information could improve doctor-patient communication, supporting the patient in chemotherapy timing decision-making.

Surgical resection versus systemic therapy for breast cancer liver metastases: Results of a European case matched comparison.

BACKGROUND: Resection of breast cancer liver metastases (BCLM) combined with systemic treatment is increasingly accepted but not offered as therapeutic option. New evidence of the additional value of surgery in these patients is scarce while prognoses without surgery remains poor. PATIENTS AND METHODS: For this case matched analysis, all nationally registered patients with BCLM confined to the liver in the Netherlands (systemic group; N = 523) were selected and compared with patients who received systemic treatment and underwent hepatectomy (resection group; N = 139) at a hepatobiliary centre in France. Matching was based on age, decade when diagnosed, interval to metastases, maximum metastases size, single or multiple tumours, chemotherapy, hormonal or targeted therapy after diagnosis. Based on published guidelines, palliative systemic treatment strategies are similar in both European countries. RESULTS: Between 1983 and 2013, 3894 patients were screened for inclusion. Overall median follow-up was 80 months (95% CI 70-90 months). The median, 3- and 5-year overall survival of the whole population was 19 months, 29% and 19%, respectively. The resection and systemic group had median survival of 73 vs. 13 months (P < 0.001), respectively. Three and 5-year survival was 18% and 10% for the systemic group and 75% and 54% for the resection group, respectively. After matching, the resection group had a median overall survival of 82 months with a 3- and 5-year overall survival of 81% and 69%, respectively, compared with a median overall survival of 31 months in the systemic group with a 3- and 5-year overall survival of 32% and 24%, respectively (HR 0.28, 95% CI 0.15-0.52; P < 0.001). CONCLUSIONS: For patients with BCLM, liver resection combined with systemic treatment results in improved overall survival compared to systemic treatment alone. Liver resection should be considered in selected cases.

The effect of being informed on receiving immediate breast reconstruction in breast cancer patients.

INTRODUCTION: In previous research from the NABON breast cancer audit, observed hospital variation in immediate breast reconstruction (IBR) rates in the Netherlands could not be fully explained by tumour, patient, and hospital factors. The process of information provision and decision-making may also contribute to the observed variation; the objective of the current study was to give insight in the underlying decision-making process for IBR and to determine the effect of being informed about IBR on receiving IBR. METHODS: A total of 502 patients with IBR and 716 without IBR treated at twenty-nine hospitals were invited to complete an online questionnaire on obtained information and decision-making regarding IBR. The effect of being informed about IBR on receiving IBR was determined by logistic regression analysis. RESULTS: Responses from five hundred and ten patients (n = 229 IBR, n = 281 without IBR) were analysed. Patients with IBR compared to patients without reconstruction showed a difference in patient, tumour, treatment (including radiotherapy), and hospital characteristics. Patients with IBR were more often informed about IBR as a treatment option (99% vs 73%), they discussed (dis)advantages more often with their physician (86% vs 68%), and they were more often involved in shared decision-making (91% vs 67%) compared to patients without IBR. Multivariate logistic regression analysis, corrected for confounders, showed that being informed about IBR increased the odds for receiving IBR fourteen times (p < 0.001). CONCLUSIONS: The positive effect of being informed about IBR on receiving IBR stresses the importance of treatment information in the decision-making process for IBR.

Patients' experiences with decisions on timing of chemotherapy for breast cancer.

INTRODUCTION: Despite potential advantages, application of chemotherapy in the neo-adjuvant (NAC) instead of adjuvant (AC) setting for breast cancer (BC) patients varies among hospitals. The aim of this study was to gain insight in patients' experiences with decisions on the timing of chemotherapy for stage II and III BC. MATERIALS AND METHODS: A 35-item online questionnaire was distributed among female patients (age>18) treated with either NAC or AC for clinical stage II/III invasive BC in 2013-2014 in the Netherlands. Outcome measures were the experienced exchange of information on the possible choice between both options and patients' involvement in the final decision on chemotherapy timing. Chemotherapy treatment experience was measured with the Cancer Therapy Satisfaction Questionnaire (CTSQ). RESULTS: Of 805 invited patients, 49% responded (179 NAC, 215 AC). NAC-treated patients were younger and more often treated in teaching/academic hospitals and high-volume hospitals. Information on the possibility of NAC was given to a minority of AC-treated patients (AC, stage II:14%, stage III: 31%). Information on pros and cons of both NAC and AC was rated sufficient in about three fourth of respondents. Respondents not always felt having a choice in the timing of chemotherapy (stage II: 54% NAC vs 36% AC; stage III: 26% NAC, 54% AC). CONCLUSION: The need to make a treatment decision on NAC was found to be made explicit in only a small number of adjuvant treated patients, in particular in BC stage II. Less than half of the respondents felt they had a real choice.

Hospital organizational factors affect the use of immediate breast reconstruction after mastectomy for breast cancer in the Netherlands.

OBJECTIVES: Significant hospital variation in the use of immediate breast reconstruction (IBR) after mastectomy exists in the Netherlands. Aims of this study were to identify hospital organizational factors affecting the use of IBR after mastectomy for ductal carcinoma in situ (DCIS) or invasive breast cancer (BC) and to analyze whether these factors explain the variation. MATERIALS AND METHODS: Patients with DCIS or primary invasive BC treated with mastectomy between 2011 and 2013 were selected from the national NABON Breast Cancer Audit. Hospital and organizational factors were collected with an online web-based survey. Regression analyses were performed to determine whether these factors accounted for the hospital variation. RESULTS: In total, 78% (n = 72) of all Dutch hospitals participated in the survey. In these hospitals 16,471 female patients underwent a mastectomy for DCIS (n = 1,980) or invasive BC (n = 14,491) between 2011 and 2014. IBR was performed in 41% of patients with DCIS (hospital range 0-80%) and in 17% of patients with invasive BC (hospital range 0-62%). Hospital type, number of plastic surgeons available and attendance of a plastic surgeon at the MDT meeting increased IBR rates. For invasive BC, higher percentage of mastectomies and more weekly MDT meetings also significantly increased IBR rates. Adjusted data demonstrated decreased IBR rates for DCIS (average 35%, hospital range 0-49%) and invasive BC (average 15%, hospital range 0-18%). CONCLUSION: Hospital organizational factors affect the use of IBR in the Netherlands. Although only partly explaining hospital variation, optimization of these factors could lead to less variation in IBR rates.