Added value of repeat sentinel lymph node biopsy in FDG-PET/CT node-negative patients with ipsilateral breast cancer recurrence.

PURPOSE: Repeat sentinel lymph node biopsy (rSLNB) has been suggested for axillary staging in clinically node-negative (cN0) patients with ipsilateral breast tumor recurrence (IBTR). Although rSLNB is technically feasible in this group of patients, the clinical value has not been established. We aimed to assess the added value of rSLNB in cN0 patients with IBTR who underwent optimal clinical staging with FDG-PET/CT. METHODS: This retrospective single-center cohort study included 119 patients with IBTR-staged cT1-4N0M0 with FDG-PET/CT who underwent rSLNB between 2006 and 2020. Overall recurrence-free survival (RFS) and overall survival (OS) were calculated for subgroups with tumor-positive, tumor negative, and unsuccessful rSLNB. RESULTS: rSLNB was successful in 79 (66%) of the 119 included patients, of whom 70 (59%) had a tumor negative and 9 (8%) a tumor-positive rSLNB; rSLNB was unsuccessful in the remaining 40 (34%) patients. Patients with a tumor-positive rSLNB had poorer overall 5-year RFS compared to patients with a tumor negative or unsuccessful rSLNB (44% vs. 86% vs. 90%, p = 0.004). Although patients with a tumor-positive rSLNB had worse RFS, the 10-year OS was comparable to a tumor negative or unsuccessful rSLNB (89% vs. 89% vs. 95%, p = 0.701). CONCLUSION: The incidence of a tumor-positive rSLNB in patients with a negative FDG-PET/CT is low and does not change survival. Therefore, in cN0 patients with IBTR who underwent optimal clinical staging with FDG-PET/CT, we support a patient- and tumor-tailored treatment strategy in which rSLNB may be omitted.

Toward omitting sentinel lymph node biopsy after neoadjuvant chemotherapy in patients with clinically node-negative breast cancer.

BACKGROUND: The nodal positivity rate after neoadjuvant chemotherapy (ypN+) in patients with clinically node-negative (cN0) breast cancer is low, especially in those with a pathological complete response of the breast. The aim of this study was to identify characteristics known before surgery that are associated with achieving ypN0 in patients with cN0 disease. These characteristics could be used to select patients in whom sentinel lymph node biopsy may be omitted after neoadjuvant chemotherapy. METHODS: This cohort study included patients with cT1-3 cN0 breast cancer treated with neoadjuvant chemotherapy followed by breast surgery and sentinel node biopsy between 2013 and 2018. cN0 was defined by the absence of suspicious nodes on ultrasound imaging and PET/CT, or absence of tumour cells at fine-needle aspiration. Univariable and multivariable logistic regression analyses were performed to determine predictors of ypN0. RESULTS: Overall, 259 of 303 patients (85.5 per cent) achieved ypN0, with high rates among those with a radiological complete response (rCR) on breast MRI (95·5 per cent). Some 82 per cent of patients with hormone receptor-positive disease, 98 per cent of those with triple-negative breast cancer (TNBC) and all patients with human epidermal growth factor receptor 2 (HER2)-positive disease who had a rCR achieved ypN0. Multivariable regression analysis showed that HER2-positive (odds ratio (OR) 5·77, 95 per cent c.i. 1·91 to 23·13) and TNBC subtype (OR 11·65, 2·86 to 106·89) were associated with ypN0 status. In addition, there was a trend toward ypN0 in patients with a breast rCR (OR 2·39, 0·95 to 6·77). CONCLUSION: The probability of nodal positivity after neoadjuvant chemotherapy was less than 3 per cent in patients with TNBC or HER2-positive disease who achieved a breast rCR on MRI. These patients could be included in trials investigating the omission of sentinel node biopsy after neoadjuvant chemotherapy.

Breast-contour preserving procedures for early-stage breast cancer: a population-based study of the trends, variation in practice and predictive characteristics in Denmark and the Netherlands.

PURPOSE: Breast-contour preservation (BCP) is possible for most women treated for early-stage breast cancer. BCP can be defined as primary breast-conserving treatment (BCT), neoadjuvant chemotherapy (NAC) followed by BCT and immediate postmastectomy breast reconstruction (IBR). This study provides insight in current BCP strategies in Denmark and the Netherlands and aims to identify opportunities for improvement within both countries. METHODS: A total of 92,881 patients with early-stage breast cancer who were operated in Denmark and the Netherlands between 2012 and 2017 were selected from the Danish Breast Cancer Group and the Dutch National Breast Cancer Audit databases. BCP procedures and predictive factors were analyzed within and between both countries. RESULTS: BCP was achieved in 76.7% (n = 16,355) of the Danish and in 74.5% (n = 53,328) of the Dutch patients. While BCP rate did not change significantly over time in Denmark (p = 0.250), a significant increase in BCP rate from 69.5% in 2012 to 78.5% in 2017 (p < 0.001) was observed in the Netherlands. In both countries, variation in BCP rates between hospitals decreased over time. NAC followed by BCT and postmastectomy IBR was substantially more often used in the Netherlands compared to Denmark, specifically in patients younger than 50 years. CONCLUSIONS: In more than 75% of all Danish and Dutch patients, surgically treated for early-stage breast cancer, the breast-contour was preserved. The different use of BCP strategies within Denmark and the Netherlands and the differences observed between hospitals in both countries emphasize the need for more (inter)national consensus on treatment modalities.

Nationwide population-based study of the impact of immediate breast reconstruction after mastectomy on the timing of adjuvant chemotherapy.

BACKGROUND: Initiation of adjuvant chemotherapy within 6-12 weeks after mastectomy is recommended by guidelines. The aim of this population-based study was to investigate whether immediate breast reconstruction (IBR) after mastectomy reduces the likelihood of timely initiation of adjuvant chemotherapy. METHODS: All patients with breast cancer who had undergone mastectomy and adjuvant chemotherapy between 2012 and 2016 in the Netherlands were identified. Time from surgery to adjuvant chemotherapy was categorized as within 6 weeks or after more than 6 weeks, within 9 weeks or after more than 9 weeks, and within 12 weeks or after more than 12 weeks. The impact of IBR on the initiation of adjuvant chemotherapy for these three scenarios was estimated using propensity score matching to adjust for treatment by indication bias. RESULTS: A total of 6300 patients had undergone primary mastectomy and adjuvant chemotherapy, of whom 1700 (27·0 per cent) had received IBR. Multivariable analysis revealed that IBR reduced the likelihood of receiving adjuvant chemotherapy within 6 weeks (odds ratio (OR) 0·76, 95 per cent c.i. 0·66 to 0·87) and 9 weeks (0·69, 0·54 to 0·87), but not within 12 weeks (OR 0·75, 0·48 to 1·17). Following propensity score matching, IBR only reduced the likelihood of receiving adjuvant chemotherapy within 6 weeks (OR 0·95, 0·90 to 0·99), but not within 9 weeks (OR 0·97, 0·95 to 1·00) or 12 weeks (OR 1·00, 0·99 to 1·01). CONCLUSION: Postmastectomy IBR marginally reduced the likelihood of receiving adjuvant chemotherapy within 6 weeks, but not within 9 or 12 weeks. Thus, IBR is not contraindicated in patients who need adjuvant chemotherapy after mastectomy.

ANTECEDENTES: Las guías clínicas recomiendan iniciar la quimioterapia adyuvante entre las 6 y las 12 semanas después de la mastectomía. El objetivo de este estudio de base poblacional fue investigar si la reconstrucción inmediata de la mama (immediate breast reconstruction, IBR) tras mastectomía reduce la posibilidad de iniciar la quimioterapia adyuvante en el momento adecuado. MÉTODOS: Se identificaron todas las pacientes con cáncer de mama a las que se había realizado mastectomía y quimioterapia adyuvante entre el 2012 y el 2016 en los Países Bajos. El tiempo transcurrido entre la cirugía y la quimioterapia adyuvante se clasificó en tres grupos: ≤ 6 versus > 6 semanas, ≤ 9 versus > 9 semanas y ≤ 12 versus > 12 semanas. El impacto de la IBR en el inicio de la quimioterapia adyuvante en estos tres escenarios se estimó mediante un análisis de emparejamiento por puntaje de propensión para ajustar el tratamiento por sesgo de indicación. RESULTADOS: Se realizó una mastectomía primaria y quimioterapia adyuvante en 6.300 pacientes, de las que a 1.700 (27%) se hizo una IBR. El análisis multivariable demostró que la IBR redujo la probabilidad de recibir quimioterapia adyuvante dentro de las 6 y 9 semanas (razón de oportunidades, odds ratio, OR 0,76; i.c. del 95% 0,66-0,87 y OR 0,69; i.c. del 95% 0,54-0,87, respectivamente), pero no dentro de las 12 semanas (OR 0,75, i.c. del 95% 0,48-1,17). Al emparejar mediante el análisis de puntaje de propensión, la IBR solo redujo la probabilidad de recibir quimioterapia adyuvante dentro de las 6 semanas (OR 0,95; i.c. del 95%: 0,90 a 0,99), pero no dentro de las 9 ó 12 semanas (OR 0,97; i.c. del 95%: 0,95 a 1,00 y OR 1,00, i.c. del 95% 0,99-1,01). CONCLUSIÓN: La IBR postmastectomía disminuyó marginalmente la probabilidad de recibir quimioterapia adyuvante dentro de las 6 semanas, pero no más allá de las 9 ó 12 semanas. Por lo tanto, la IBR postmastectomía no está contraindicada en pacientes que necesitan tratamiento con quimioterapia adyuvante.

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.

Identifying pathologic complete response of the breast after neoadjuvant systemic therapy with ultrasound guided biopsy to eventually omit surgery: Study design and feasibility of the MICRA trial (Minimally Invasive Complete Response Assessment).

PURPOSE: Improvements in neoadjuvant systemic therapy (NST) for breast cancer patients have led to increasing rates of pathologic complete response (pCR). The MICRA trial (NTR6120) aims at identifying pCR with post-NST biopsies. Here, we report the study design and feasibility. METHODS: The MICRA-trial is a multi-center prospective cohort study. Patients with a pre-NST placed marker and radiologic complete (rCR) or partial response on MRI after NST are eligible for inclusion. Ultrasound guided biopsy of the original tumor area is performed. Pathology results of the biopsies and surgery specimens are compared. The primary endpoint is false-negative rate of biopsies in identifying pCR. RESULTS: During the first year of the trial 58 patients with rCR were included. One patient was a screening failure and excluded for analysis. Twenty-one percent had hormone receptor (HR)+/HER2- tumors, 21% HR+/HER2+ tumors, 18% HR-/HER2+ tumors and 40% TN tumors. Overall pCR was 68%. In seven patients biopsies could not be obtained: in 6 patients, the marker could not be identified on ultrasound in the OR and in 1 patient there were technical difficulties. A median of eight biopsies was obtained (range 4-9). The median of histopathological representative biopsies was 4 (range 1-8). CONCLUSION: Ultrasound guided biopsy of the breast in patients with excellent response on MRI after NST is feasible. Accuracy results of the MICRA trial will be presented after inclusion of 525 patients to determine if ultrasound guided biopsy is an accurate alternative to surgical resection for assessment of pCR after NST.

Major Reduction in Axillary Lymph Node Dissections After Neoadjuvant Systemic Therapy for Node-Positive Breast Cancer by combining PET/CT and the MARI Procedure.

BACKGROUND: Axillary lymph node dissection (ALND) is frequently performed for node-positive (cN+) breast cancer patients. Combining positron emission tomography/computed tomography (PET/CT) before-NST and the MARI (marking axillary lymph nodes with radioactive iodine seeds) procedure after neoadjuvant systemic therapy (NST) has the potential for avoiding unnecessary ALNDs. This report presents the results from implementation of this strategy. METHODS: All breast cancer patients treated with NST at the Netherlands Cancer Institute who underwent a PET/CT and the MARI procedure from July 2014 to July 2017 were included in the study. All the patients underwent tailored axillary treatment according to a protocol based on the combined results of PET/CT before NST and the MARI procedure after NST. With this protocol, patients showing one to three FDG-avid axillary lymph nodes (ALNs) on PET/CT (cN<4) and a tumor-negative MARI node receive no further axillary treatment. All cN (<4) patients with a tumor-positive MARI node receive locoregional radiotherapy, as well as patients with four or more FDG-avid ALNs [cN(4+)] and a tumor-negative MARI node after NST. An ALND is performed only for cN(4+) patients with a tumor-positive MARI node. RESULTS: The data of 159 patients who received a PET/CT before NST and a MARI procedure after NST were analyzed. Of these patients, 110 had one to three FDG-avid ALNs and 49 patients showed four or more FDG-avid ALNs on PET/CT before NST. For 130 patients (82%), ALND was omitted. Locoregional radiotherapy was administered to 91 patients (57%), and 39 patients (25%) received no further axillary treatment. CONCLUSION: Combining pre-NST axillary staging with PET/CT and post-NST staging with the MARI procedure resulted in an 82% reduction of ALNDs for cN + breast cancer patients.

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.

Breast conserving surgery for extensive DCIS using multiple radioactive seeds.

BACKGROUND AND OBJECTIVES: Breast conserving surgery (BCS) can be challenging for large regions of ductal carcinoma in situ (DCIS), resulting in high rates of positive resection margins. Radioactive seed localization (RSL) using multiple radioactive iodine (125I) seeds can be used to bracket extensive DCIS (eDCIS). The goal of this study was to retrospectively compare the use of a single or multiple 125I seeds in RSL to enable BCS in patients with eDCIS. METHODS: All patients with eDCIS (area of ≥3.0 cm) who underwent either single or multiple-seed RSL between January 2008 and December 2016 were included. Patient, tumor and surgery characteristics were compared between both groups. Primary outcome measures were positive resection margin and re-operation rates. RESULTS: Respectively 48 and 58 patients with eDCIS underwent single- and multiple-seed RSL and subsequent BCS. The rate of positive resection margin (focal and more than focal) with single-seed RSL was 47.9%, compared to 29.3% with multiple-seed RSL (p = 0.06). The re-operation rate was 39.6% with single-seed RSL and 20.7% in the multiple-seed RSL group (p = 0.05). CONCLUSION: Multiple-seed RSL enables bracketing of large areas of DCIS, with the potential to decrease the high rate of positive resection margins in this patient group.

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.

Variation in use of neoadjuvant chemotherapy in patients with stage III breast cancer: Results of the Dutch national breast cancer audit.

OBJECTIVES: Neoadjuvant chemotherapy (NAC) is important in the optimal treatment of patients with locally advanced (stage III) breast cancer (BC). The objective of this study was to examine the clinical practice of NAC for stage III BC patients in all Dutch hospitals participating in BC care. MATERIALS AND METHODS: All patients aged 18-70 years who received surgery for stage III BC from January 2011 to September 2015 were selected from the national multidisciplinary NABON Breast Cancer Audit. Multivariable logistic regression was used to assess independent predictors of NAC use, focussing on hospital factors. RESULTS: A total of 1230 out of 1556 patients with stage III BC (79%) received NAC prior to surgery. The use of NAC did not change over time. We observed a large variation of NAC use between hospitals (0-100%). Age <50 years, breast MRI, large tumour size, advanced nodal disease, negative hormone receptor status and hospital participation in neoadjuvant clinical studies were significant independent predictors of NAC use (all P < 0.001). NAC use in stage III BC was not influenced by hospital type and hospital surgical volume. After adjustment for all independent predictors, variation in NAC use between hospitals remained (0% to 97%). CONCLUSION: NAC was used in 79% of patients with stage III BC, which represent a high quality of care in the NL. Patient, tumour, clinical management and hospital factors could not explain considerable variation in its use between hospitals. Hospital participation in neoadjuvant studies did show to improve the use of NAC in daily practice.

The intraoperative assessment of sentinel nodes - Standards and controversies.

Intraoperative assessment of sentinel lymph nodes (SLNs) has the advantage of allowing breast cancer patients with tumor-positive SLNs to avoid a second surgery by immediately proceeding to axillary lymph node dissection (ALND). However, there are several reasons why the use of intraoperative assessment should be questioned. Whereas ALND was traditionally advised for all breast cancer patients with tumor-positive lymph nodes for axillary staging and locoregional control, more recent studies have demonstrated safety of omitting ALND in a substantial number of patients. In addition, there are concerns about the accuracy of intraoperative assessment methods including frozen section analysis, touch preparation cytology and one-step nucleic acid amplification. Moreover, intraoperative assessment of SLNs denies patients the opportunity to contribute to their treatment planning. In our opinion, intraoperative assessment of axillary lymph nodes should be reserved for patients who still have a strict indication for ALND. Patients with clinical node negative disease (cN0) and one or two positive SLNs can be safely treated with breast conserving surgery and radiotherapy. There has been more controversy for cN0 patients who are treated with mastectomy since radiotherapy is not routinely administered in these patients. However, there is increasing evidence that ALND may be omitted in patients undergoing mastectomy who have a low tumor-burden in their SLNs. Therefore, we defend the position that in cN0 patients undergoing mastectomy, SLNB should be performed and full pathologic evaluation of the SLN should be awaited. In cN0 patients undergoing neoadjuvant systemic therapy (NST) intraoperative assessment of SLNs can be omitted since ALND will not provide therapeutic benefit. It is being hypothesized that patients with limited axillary disease prior to NST who remain node-positive after NST could be treated safely with axillary radiotherapy instead of ALND. In these patients, omitting intraoperative assessment might be a reasonable option. In patients with extensive nodal disease prior to NST intraoperative assessment of axillary lymph nodes should be performed.

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.

Feasibility of magnetic marker localisation for non-palpable breast cancer.

OBJECTIVES: Accurate tumour localisation is essential for breast-conserving surgery of non-palpable tumours. Current localisation technologies are associated with disadvantages such as logistical challenges and migration issues (wire guided localisation) or legislative complexities and high administrative burden (radioactive localisation). We present MAgnetic MArker LOCalisation (MaMaLoc), a novel technology that aims to overcome these disadvantages using a magnetic marker and a magnetic detection probe. This feasibility study reports on the first experience with this new technology for breast cancer localisation. MATERIALS AND METHODS: Fifteen patients with unifocal, non-palpable breast cancer were recruited. They received concurrent placement of the magnetic marker in addition to a radioactive iodine seed, which is standard of care in our clinic. In a subset of five patients, migration of the magnetic marker was studied. During surgery, a magnetic probe and gammaprobe were alternately used to localise the markers and guide surgery. The primary outcome parameter was successful transcutaneous identification of the magnetic marker. Additionally, data on radiologist and surgeon satisfaction were collected. RESULTS: Magnetic marker placement was successful in all cases. Radiologists could easily adapt to the technology in the clinical workflow. Migration of the magnetic marker was negligible. The primary endpoint of the study was met with an identification rate of 100%. Both radiologists and surgeons reflected that the technology was intuitive to use and that it was comparable to radioactive iodine seed localisation. CONCLUSION: Magnetic marker localisation for non-palpable breast cancer is feasible and safe, and may be a viable non-radioactive alternative to current localisation technologies.

Large variation between hospitals in immediate breast reconstruction rates after mastectomy for breast cancer in the Netherlands.

BACKGROUND: The present study aimed to describe the use of immediate breast reconstruction (IBR) after mastectomy for invasive breast cancer and ductal carcinoma in situ (DCIS) in hospitals in the Netherlands and determine whether patient and tumor factors account for the variation. METHODS: Patients undergoing mastectomy for primary invasive breast cancer or DCIS diagnosed between January 1, 2011 and December 31, 2013 were selected from the NABON Breast Cancer Audit. All the 92 hospitals in the Netherlands were included. The use of IBR in all hospitals was compared using unadjusted and adjusted analyses. Patient and tumor factors were evaluated by univariate and multivariate analyses. RESULTS: In total, 16,953 patients underwent mastectomy: 15,072 for invasive breast cancer and 1881 for DCIS. Unadjusted analyses revealed considerable variation between hospitals in postmastectomy IBR rates for invasive breast cancer (mean 17%; range 0-64%) and DCIS (mean 42%; range 0-83%). For DCIS, younger age and multifocal disease were factors that significantly increased IBR rates. For patients diagnosed with invasive breast cancer, IBR was more often used in younger patients, multifocal tumors, smaller tumors, tumors with a lower grade, absence of lymph node involvement, ductal carcinomas, or hormone-receptor positive/HER2-positive tumors. After case-mix adjustments for these factors, the variation in the use of IBR between hospitals remained large (0-43% for invasive breast cancer and 0-74% for DCIS). CONCLUSIONS: A large variation between hospitals was found in postmastectomy IBR rates in the Netherlands for both invasive breast cancer and DCIS even after adjustment for patient and tumor factors.

Radioactive seed localization in breast cancer treatment.

BACKGROUND: Breast cancer screening, improved imaging and neoadjuvant systemic therapy (NST) have led to increased numbers of non-palpable tumours suitable for breast-conserving surgery (BCS). Accurate tumour localization is essential to achieve a complete resection in these patients. This study evaluated the role of radioactive seed localization (RSL) in improving breast- and axilla-conserving surgery in patients with breast cancer with or without NST. METHODS: Patients who underwent RSL between 2007 and 2014 were included. Learning curves were analysed by the rates of minimally involved (in situ/invasive tumour cells on a length of 0-4 mm on ink) and positive resection margins (over 4 mm on ink) after BCS, and the median resection volume over time. RESULTS: A total of 367 patients with in situ carcinomas and 199 with non-palpable invasive breast cancer underwent RSL before primary surgery. A further 697 patients had RSL before NST, of whom 206 also underwent RSL of a histologically verified axillary lymph node metastasis. BCS was performed in 93·2 and 87·9 per cent of patients undergoing primary surgery for in situ and invasive tumours respectively, and 57·5 per cent of those in the NST group. The rate of BCS with positive resection margins was low and stable over time in the three groups (9·1, 9·7 and 11·2 per cent respectively). The median resection volume decreased significantly with time in the invasive cancer and NST groups. CONCLUSION: In the present study of more than 1200 patients and 7 years of experience, RSL was shown to facilitate breast- and axilla-conserving surgery in a diverse patient population. There was a significant reduction in resection volume while maintaining low positive resection margin rates after BCS.

Simultaneous use of an (125)I-seed to guide tumour excision and (99m)Tc-nanocolloid for sentinel node biopsy in non-palpable breast-conserving surgery.

PURPOSE: In the present study we describe patients with non-palpable breast lesions, in which an Iodine-125 ((125)I)-marker (or "seed") for excision of the primary tumour and Technetium-99m nanocolloid ((99m)Tc-nanocolloid) for sentinel node biopsy (SNB) are used simultaneously. The purpose was to investigate any interference between (125)I-seeds and (99m)Tc-nanocolloid by an in vitro and in vivo analysis. METHODS: Contrast/interference-ratios between (125)I and (99m)Tc count-rates were determined in vitro using a realistic simulation model. Measurements were performed with 3 gamma-probes with different crystal materials. In 25 consecutive patients (99m)Tc-nanocolloid was intratumourally administered at the site of a previously implanted (125)I-seed. Respectively, the (125)I-setting and (99m)Tc-setting of the gamma-probe guided the wide local excision and SNB and maximum counts-per-second (cps) were measured. RESULTS: In vitro the different probes varied in (125)I- and (99m)Tc-sensitivity. The contrast-ratio between (125)I and (99m)Tc in the (125)I-channel was 4.6 for a 3-month-old (125)I-seed using the most appropriate gamma-probe. In vivo the gamma-probe in the (125)I-setting measured a median of 16,300 cps at the tumour site compared to 4820 cps using the (99m)Tc-setting. The (125)I-seed could be well distinguished from the (99m)Tc-nanocolloid in 92% of the patients and 96% required a single operation. The SNB was successful in all patients. CONCLUSIONS: Simultaneous use of (125)I-seeds and (99m)Tc-nanocolloid is possible under well-standardised conditions. Non-palpable breast lesions can be safely excised using the (125)I-seed in combination with a SN procedure. Use of (125)I-seeds is a next step within fine-tuning breast-conserving surgery that should lead to further investigation to confirm its value.

Neoadjuvant chemotherapy in ER+ HER2- breast cancer: response prediction based on immunohistochemical and molecular characteristics.

A pathological complete remission (pCR) is rarely achieved by neoadjuvant chemotherapy in estrogen receptor-positive (ER+) HER2-negative (HER2-) tumors. Therefore, its use might be questionable in specific groups of this tumor type. To select which patients benefit and which could be spared neoadjuvant chemotherapy, we tested standard pathology and molecular markers in ER+ HER2- breast tumors. Pretreatment biopsies were available from 211 ER+ HER2- tumors, who had been treated with neoadjuvant chemotherapy (adriamycin/cyclophosphamide). mRNA expression data were available for 132 tumors. We determined progesterone receptor expression (PR), endocrine sensitivity, HER2 expression, histology, proliferation, and molecular subtypes. We correlated these data to chemotherapy response using pCR rates and the previously published neoadjuvant response index (NRI). PR-negative tumors (n = 65, 30.8%) and luminal B type tumors (n = 43, 20.4%) responded significantly better to chemotherapy than other tumors. These associations remained significant in multivariate analysis. However, even in the subgroup of patients with the lowest response rate, comprising tumors that had both a positive-PR expression and the luminal A subtype (n = 58, 44%), the majority of the patients had downstaging because of chemotherapy. For histology (lobular vs. ductal), endocrine sensitivity, and proliferation, no associations with chemotherapy response were observed. Gene expression array analysis resulted in 28 significant genes (FDR < 0.1). PR expression and luminal B status are associated with a better response to neoadjuvant chemotherapy. However, both markers had only weak response predictive power, and it was not possible to identify a subgroup with no or only minimal chemotherapy benefit. Therefore, the decision to refrain from neoadjuvant chemotherapy to ER+ HER2- breast tumors should not be based on predictive markers, but exclusively on estimates of prognosis.

Indicators of homologous recombination deficiency in breast cancer and association with response to neoadjuvant chemotherapy.

BACKGROUND: Tumors with homologous recombination deficiency (HRD), such as BRCA1-associated breast cancers, are not able to reliably repair DNA double-strand breaks (DSBs) and are therefore highly sensitive to both DSB-inducing chemotherapy and poly (ADP-ribose) polymerase inhibitors. We have studied markers that may indicate the presence of HRD in HER2-negative breast cancers and related them to neoadjuvant chemotherapy response. PATIENTS AND METHODS: Array comparative genomic hybridization (aCGH), BRCA1 promoter methylation, BRCA1 messenger RNA (mRNA) expression and EMSY amplification were assessed in 163 HER2-negative pretreatment biopsies from patients scheduled for neoadjuvant chemotherapy. RESULTS: Features of BRCA1 dysfunction were frequent in triple-negative (TN) tumors: a BRCA1-like aCGH pattern, promoter methylation and reduced mRNA expression were observed in, respectively, 57%, 25% and 36% of the TN tumors. In ER+ tumors, a BRCA2-like aCGH pattern and the amplification of the BRCA2 inhibiting gene EMSY were frequently observed (43% and 13%, respectively) and this BRCA2-like profile was associated with a better response to neoadjuvant chemotherapy. CONCLUSIONS: Abnormalities associated with BRCA1 inactivation are present in about half of the TN breast cancers but were not predictive of chemotherapy response. In ER+/HER2- tumors, a BRCA2-like aCGH pattern was predictive of chemotherapy response. These findings should be confirmed in independent series.