Omitting SLNB in Breast Cancer: Is a Nomogram the Answer?

BACKGROUNDS: Sentinel lymph node biopsy (SLNB) is standard care as a staging procedure in patients with invasive breast cancer. The axillary recurrence rate, even after positive SLNB, is low. This raises serious doubts regarding the clinical value of SLNB in early breast cancer. The purpose of this study is to select patients with low suspected axillary burden in whom SLNB might be omitted. PATIENTS AND METHODS: We retrospectively analyzed 2015 primary breast cancer patients between 2007 and 2015, with 982 patients allocated to the training and 961 to the validation cohort. Variables associated with nodal disease were analyzed and used to build a nomogram for predicting nodal disease. RESULTS: A total of 32.8% of patients had macrometastatic disease. A predictive model was constructed based on age, cN0, morphology, grade, multifocality, and tumor size with an area under the receiver operating characteristic curve (AUC) of 0.83. Considering a false-negative rate of 5%, 32.8% of patients could be spared axillary surgery. In a subanalysis of patients with relatively favorable characteristics, 26.8% had less than 5% chance of macrometastases. CONCLUSIONS: We present a model with excellent predictive value that can select one-third of patients in whom SLNB is deemed not necessary because of less than 5% chance of nodal involvement. Whether missing 1 in 20 patients with macrometastatic disease is worthwhile balanced against preventing side-effects of the SLN procedure remains to be established. A number of ongoing large prospective trials evaluating the outcome of omitting SLNB are awaited. Meanwhile, this nomogram may be used for individual decision-making.

Incidence, clinical features, and outcomes of special types in breast cancer in a single institution population.

The low incidence of special types of breast cancer hinders adequate clinical research efforts. As such, collecting sufficient data to develop well-established therapy strategies are difficult. The aim of our study was to obtain more data on these special types in order to better understand the different characteristics and optimize therapy strategies. A single-institution retrospective cohort study from January 2007 until September 2015. One hundred and five patients remained after excluding the patients with invasive ductal and lobular carcinoma. The percentage of these so called special types in this population was 4%. Tubular carcinoma, cribriform carcinoma, carcinoma with medullary features, carcinoma with apocrine differentiation, secretory carcinoma, mucinous carcinoma, and invasive papillary carcinoma had a good or excellent prognosis, while invasive micropapillary carcinoma, adenoid cystic carcinoma, metaplastic carcinoma, and carcinoma with neuroendocrine features had a worse prognosis. Special types of breast cancer form a heterogeneous group. Submitting them all to the same treatment modality may lead to both over- and under-treatment. We need to combine our data to optimize treatment strategies for the different special types.

Using a gene expression signature when controversy exists regarding the indication for adjuvant systemic treatment reduces the proportion of patients receiving adjuvant chemotherapy: a nationwide study.

PURPOSE: The Dutch national guideline advises use of gene-expression signatures, such as the 70-gene signature (70-GS), in case of ambivalence regarding the benefit of adjuvant chemotherapy (CT). In this nationwide study, the impact of 70-GS use on the administration of CT in early breast cancer patients with a dubious indication for CT is assessed. METHODS: Patients within a national guideline directed indication area for 70-GS use who were surgically treated between November 2011 and April 2013 were selected from the Netherlands Cancer Registry database. The effect of 70-GS use on the administration of CT was evaluated in guideline- and age-delineated subgroups addressing potential effect of bias by linear mixed-effect modeling and instrumental variable (IV) analyses. RESULTS: A total of 2,043 patients within the indicated area for 70-GS use were included, of whom 298 received a 70-GS. Without use of the 70-GS, 45% of patients received CT. The 70-GS use was associated with a 9.5% decrease in CT administration (95% confidence interval (CI): -15.7 to -3.3%) in linear mixed-effect model analyses and IV analyses showed similar results (-9.9%; 95% CI: -19.3 to -0.4). CONCLUSION: In patients in whom the Dutch national guidelines suggest the use of a gene-expression profile, 70-GS use is associated with a 10% decrease in the administration of adjuvant CT.Genet Med 18 7, 720-726.Genetics in Medicine (2016); 18 7, 720-726. doi:10.1038/gim.2015.152.

Repeat sentinel node biopsy should be considered in patients with locally recurrent breast cancer.

Most patients with locally recurrent breast cancer undergo axillary lymph node dissection (ALND). However, repeat sentinel node biopsy (SNB) could provide regional nodal staging and obviate the need for standard ALND. The Sentinel Node and Recurrent Breast Cancer (SNARB) study is a Dutch nationwide registration study conducted to determine feasibility, aberrant drainage rates, and clinical consequences of repeat SNB. A total of 536 patients with locally recurrent non-metastatic breast cancer underwent lymphatic mapping and repeat SNB in 29 Dutch hospitals. A repeat sentinel node (SN) was identified in 333 of 536 patients (62.1 %) and surgically harvested in 287 patients (53.5 %). Aberrant lymph drainage was observed in 180 (54.1 %) of the 333 patients, more often after previous ALND (81.9 %) than SNB (28.4 %; P < 0.001). In 230 patients (80.1 %), the retrieved SN was tumor negative; 17 SNs (5.9 %) contained a micrometastasis and 29 (10.1 %) a macrometastasis. Confirmation ALND in 31 repeat SN-negative patients revealed a macrometastasis in two patients (6.5 %). The negative predictive value (NPV) of repeat SNB was 93.6 %, and ALND was omitted in 109 of the 248 patients (44.0 %) with a negative repeat SN. In 29 of the 44 patients (63.0 %) with a positive SN, adjuvant treatment plans were altered based on the repeat SNB. Repeat SNB is a feasible procedure with a high NPV, leading to a change in management in a substantial proportion of patients. Therefore, repeat SNB should replace routine ALND and serve as the standard of care in recurrent breast cancer.

Improving the Success Rate of Repeat Sentinel Node Biopsy in Recurrent Breast Cancer.

PURPOSE: Repeat sentinel node biopsy (SNB) is an alternative to axillary lymph node dissection (ALND) for axillary staging in recurrent breast cancer. This study was conducted to determine factors associated with technical success of repeat SNB. METHODS: A total of 536 patients with locally recurrent nonmetastatic breast cancer underwent lymphatic mapping (LM) and repeat SNB in 29 Dutch hospitals. RESULTS: A total of 179 patients previously underwent breast-conserving surgery (BCS) with SNB, 262 patients BCS with ALND and 61 patients mastectomy, 35 with SNB and 26 with ALND. Another 34 patients underwent breast surgery without axillary interventions. A repeat sentinel node (SN) was identified in 333 patients (62.1 %) and was successfully removed in 235 (53.5 %). The overall repeat SN identification rate was 62.1 %, varying from 35 to 100 % in the participating hospitals. Previous radiotherapy of the breast [odds ratio (OR) 0.16; 95 % confidence interval (CI) 0.03-0.84], subareolar tracer injection (OR 0.34; 95 % CI 0.16-0.73), and a 2-day LM protocol (OR 0.57; 95 % CI 0.33-0.97) after previous BCS were independently associated with failure of SN identification. Injection of a larger amount of tracer (>180 MBq) led to a higher identification rate (OR 4.40; 95 % CI 1.45-13.32). CONCLUSIONS: Repeat SNB is a technically feasible procedure for axillary staging in recurrent breast cancer patients. Previous radiotherapy appears to be associated with failure of SN identification. Injection with a larger amount of tracer (>180 MBq) leads to a higher identification rate; subareolar injection and a 2-day LM protocol after previous BCS appear to be less adequate.

Long-term impact of the 70-gene signature on breast cancer outcome.

Several studies have validated the prognostic value of the 70-gene prognosis signature (MammaPrint(R)), but long-term outcome prediction of these patients has not been previously reported. The follow-up of the consecutively treated cohort of 295 patients (<53 years) with invasive breast cancer (T1-2N0-1M0; n = 151 N0, n = 144 N1) diagnosed between 1984 and 1995, in which the 70-gene signature was previously validated, was updated. The median follow-up for this series is now extended to 18.5 years. A significant difference is seen in long-term distant metastasis-free survival (DMFS) for the patients with a low- and a high-risk 70-gene signature (DMFS p < 0.0001), as well as separately for node-negative (DMFS p < 0.0001) and node-positive patients (DMFS p = 0.0004). The 25-year hazard ratios (HRs) for all patients for DMFS and OS were 3.1 (95 % CI 2.02-4.86) and 2.9 (95 % CI 1.90-4.28), respectively. The HRs for DMFS and OS were largest in the first 5 years after diagnosis: 9.6 (95 % CI 4.2-22.1) and 11.3 (95 % CI 3.5-36.4), respectively. The 25-year HRs in the subgroup of node-negative patients for DMFS and OS were 4.57 (95 % CI 2.31-9.04) and 4.73 (95 % CI 2.46-9.07), respectively, and for node-positive patients for DMFS and OS were 2.24 (95 % CI 1.25-4.00) and 1.83 (95 % CI 1.07-3.11), respectively. The 70-gene signature remains prognostic at longer follow-up in patients <53 years of age with stage I and II breast cancer. The 70-gene signature's strongest prognostic power is seen in the first 5 years after diagnosis.

Gene expression profiling to predict the risk of locoregional recurrence in breast cancer: a pooled analysis.

The 70-gene signature (MammaPrint) has been developed to predict the risk of distant metastases in breast cancer and select those patients who may benefit from adjuvant treatment. Given the strong association between locoregional and distant recurrence, we hypothesize that the 70-gene signature will also be able to predict the risk of locoregional recurrence (LRR). 1,053 breast cancer patients primarily treated with breast-conserving treatment or mastectomy at the Netherlands Cancer Institute between 1984 and 2006 were included. Adjuvant treatment consisted of radiotherapy, chemotherapy, and/or endocrine therapy as indicated by guidelines used at the time. All patients were included in various 70-gene signature validation studies. After a median follow-up of 8.96 years with 87 LRRs, patients with a high-risk 70-gene signature (n = 492) had an LRR risk of 12.6% (95% CI 9.7-15.8) at 10 years, compared to 6.1% (95% CI 4.1-8.5) for low-risk patients (n = 561; P < 0.001). Adjusting the 70-gene signature in a competing risk model for the clinicopathological factors such as age, tumour size, grade, hormone receptor status, LVI, axillary lymph node involvement, surgical treatment, endocrine treatment, and chemotherapy resulted in a multivariable HR of 1.73 (95% CI 1.02-2.93; P = 0.042). Adding the signature to the model based on clinicopathological factors improved the discrimination, albeit non-significantly [C-index through 10 years changed from 0.731 (95% CI 0.682-0.782) to 0.741 (95% CI 0.693-0.790)]. Calibration of the prognostic models was excellent. The 70-gene signature is an independent prognostic factor for LRR. A significantly lower local recurrence risk was seen in patients with a low-risk 70-gene signature compared to those with high-risk 70-gene signature.

Is DCIS breast cancer, and how do I treat it?

Ductal carcinoma in situ (DCIS) is a pre-invasive stage of breast cancer with a heterogeneous clinical behaviour. Since the introduction of mammographic screening programmes, the incidence of DCIS has shown a dramatic increase. Treatment should focus on the prevention of progression to invasive disease. If progression occurs, poorly differentiated DCIS frequently gives rise to grade III invasive breast cancer, whereas well differentiated DCIS more often recurs as grade I invasive disease. However, at present, validated diagnostic test are lacking to predict progression accurately. The majority of women with DCIS are suitable for breast conserving therapy. Obtaining clear surgical margins is the most important goal of a local excision. Radiotherapy is effective in reducing the risk of local recurrence with about 50 % in all subgroups of patients with DCIS. (Breast cancer specific) survival of women with DCIS is excellent, and radiotherapy does not further improve this. Future research should be directed in enabling to select women who have a high risk of--invasive--recurrence, so in which radiotherapy should be standard part of the breast conserving approach, and those women with a more indolent lesion, in which after surgery a watchful waiting approach can be followed.

Relevant impact of central pathology review on nodal classification in individual breast cancer patients.

BACKGROUND: In the MIRROR study, pN0(i + ) and pN1mi were associated with reduced 5-year disease-free survival (DFS) compared with pN0. Nodal status (N-status) was assessed after central pathology review and restaging according to the sixth AJCC classification. We addressed the impact of pathology review. PATIENTS AND METHODS: Early favorable primary breast cancer patients, classified pN0, pN0(i + ), or pN1(mi) by local pathologists after sentinel node procedure, were included. We assessed the impact of pathology review on N-status (n = 2842) and 5-year DFS for those without adjuvant therapy (n = 1712). RESULTS: In all, 22% of the 1082 original pN0 patients was upstaged. Of the 623 original pN0(i + ) patients, 1% was downstaged, 26% was upstaged. Of 1137 patients staged pN1mi, 15% was downstaged, 11% upstaged. Originally, 5-year DFS was 85% for pN0, 74% for pN0(i + ), and 73% for pN1mi; HR 1.70 [95% confidence interval (CI) 1.27-2.27] and HR 1.57 (95% CI 1.16-2.13), respectively, compared with pN0. By review staging, 5-year DFS was 86% for pN0, 77% for pN0(i + ), 77% for pN1mi, and 74% for pN1 + . CONCLUSION: Pathology review changed the N-classification in 24%, mainly upstaging, with potentially clinical relevance for individual patients. The association of isolated tumor cells and micrometastases with outcome remained unchanged. Quality control should include nodal breast cancer staging.

Association of primary tumour FDG uptake with clinical, histopathological and molecular characteristics in breast cancer patients scheduled for neoadjuvant chemotherapy.

PURPOSE: The aim of this study was to evaluate the association of primary tumour (18)F-fluorodeoxyglucose (FDG) uptake with clinical, histopathological and molecular characteristics of breast cancer patients scheduled for neoadjuvant chemotherapy. Second, we wished to establish for which patients pretreatment positron emission tomography (PET)/CT could safely be omitted because of low FDG uptake. METHODS: PET/CT was performed in 214 primary stage II or III breast cancer patients in the prone position with hanging breasts. Tumour FDG uptake was qualitatively evaluated to determine the possibility of response monitoring with PET/CT and was quantitatively assessed using maximum standardized uptake values (SUV(max)). FDG uptake was compared with age, TNM stage, histology, hormone and human epidermal growth factor receptor 2 status, grade, Ki-67 and molecular subtype in univariable and multivariable analyses. RESULTS: In 203 tumours (95 %) FDG uptake was considered sufficient for response monitoring. No subgroup of patients with consistently low tumour FDG uptake could be identified. In a univariable analysis, SUV(max) was significantly higher in patients with distant metastases at staging examination, non-lobular carcinomas, tumours with negative hormone receptors, triple negative tumours, grade 3 tumours, and in tumours with a high proliferation index (Ki-67 expression). After multiple linear regression analysis, triple negative and grade 3 tumours were significantly associated with a higher SUV(max). CONCLUSION: Primary tumour FDG uptake in breast cancer patients scheduled for neoadjuvant chemotherapy is significantly higher in tumours with prognostically unfavourable characteristics. Based on tumour characteristics associated with low tumour FDG uptake, this study was unable to identify a subgroup of patients unlikely to benefit from pretreatment PET/CT.

Lymphoscintigraphy and SPECT/CT in multicentric and multifocal breast cancer: does each tumour have a separate drainage pattern? Results of a Dutch multicentre study (MULTISENT).

PURPOSE: To investigate whether lymphoscintigraphy and SPECT/CT after intralesional injection of radiopharmaceutical into each tumour separately in patients with multiple malignancies in one breast yields additional sentinel nodes compared to intralesional injection of the largest tumour only. METHODS: Patients were included prospectively at four centres in The Netherlands. Lymphatic flow was studied using planar lymphoscintigraphy and SPECT/CT until 4 h after administration of (99m)Tc-nanocolloid in the largest tumour. Subsequently, the smaller tumour(s) was injected intratumorally followed by the same imaging sequence. Sentinel nodes were intraoperatively localized using a gamma ray detection probe and vital blue dye. RESULTS: Included in the study were 50 patients. Additional lymphatic drainage was depicted after the second and/or third injection in 32 patients (64%). Comparison of planar images and SPECT/CT images after consecutive injections enabled visualization of the number and location of additional sentinel nodes (32 axillary, 11 internal mammary chain, 2 intramammary, and 1 interpectoral. A sentinel node contained metastases in 17 patients (34%). In five patients with a tumour-positive node in the axilla that was visualized after the first injection, an additional involved axillary node was found after the second injection. In two patients, isolated tumour cells were found in sentinel nodes that were only visualized after the second injection, whilst the sentinel nodes identified after the first injection were tumour-negative. CONCLUSION: Lymphoscintigraphy and SPECT/CT after consecutive intratumoral injections of tracer enable lymphatic mapping of each tumour separately in patients with multiple malignancies within one breast. The high incidence of additional sentinel nodes draining from tumours other than the largest one suggests that separate tumour-related tracer injections may be a more accurate approach to mapping and sampling of sentinel nodes in patients with multicentric or multifocal breast cancer.

The relevance of breast cancer subtypes in the outcome of neoadjuvant chemotherapy.

BACKGROUND: Breast cancer is increasingly considered a heterogeneous disease. The aim of this study was to assess the differences between histological and receptor-based subtypes in breast-conserving surgery and pathological complete response (pCR) after neoadjuvant chemotherapy. METHOD: A consecutive series of 254 patients with operable breast cancer treated with neoadjuvant chemotherapy was analyzed. Tumors were classified according to their receptor status in estrogen receptor (ER)-positive tumors (HER2-negative), triple-negative tumors, and HER2-positive tumors. The type of surgery feasible prior to neoadjuvant chemotherapy was compared with the actual surgery performed. RESULTS: The overall increase in breast-conserving surgery was 37% (73 of 198). In patients with ductal and lobular carcinomas this increase was 41% (63 of 152, 95% confidence interval [95% CI] 0.34-0.49) and 20% (7 of 35, 95% CI 0.10-0.36), respectively (P = 0.02). Half of the patients with lobular carcinoma had to undergo a secondary mastectomy because of incomplete resection margins. In ER-positive, triple-negative and HER2-positive tumors, the increase in breast-conserving surgery was 39% (42 of 109, 95% CI 0.30-0.48), 24% (11 of 45, 95% CI 0.14-0.38), and 45% (20 of 44, 95% CI 0.32-0.60) (P = 0.11). The pCR rate in ductal and lobular carcinomas was 12% (23 of 195) and 2% (1 of 42), respectively (P = 0.09). In ER-positive, triple-negative and HER2-positive tumors the pCR rates were 2% (3 of 138), 28% (16 of 57), and 18% (10 of 56), respectively. Multivariate analysis showed that the receptor-based subtype was the only significant predictor of pCR (P = 0.004). CONCLUSION: In lobular tumors the benefit with regard to breast-conserving surgery of neoadjuvant chemotherapy is questionable. Although in ER-positive tumors the pCR rate is low, the increase in breast-conserving surgery was remarkable in ductal ER-positive tumors.

[Mammary carcinoma]. / Mammacarcinoom.

In The Netherlands mamma carcinoma is diagnosed in about 12.000 women each year. The prognosis has improved due to screening, local control and adjuvant therapy. This induced a mortality reduction of 20% during the last decennium. If mamma carcinoma has been diagnosed, local surgical treatment of the breast will take place. This may be carried out by breast conserving therapy or by breast amputation. For axillary staging a sentinel node procedure is performed. In case of axillary metastasis, an axillary lymph node dissection is needed. Systemic therapy may be needed as well. This can be chemotherapy, immunotherapy, hormonal therapy or a combination. Recent developments in molecular techniques will provide individualized systemic treatment in the near future.

[Systematic breast self-examination is not a useful screening procedure, except in hereditary or familial increased risk of breast cancer]. / Systematisch borstzelfonderzoek is geen nuttige screening, behalve bij genetisch of familiair verhoogd risico op borstkanker.

Population screening for breast cancer in the Netherlands in women 50-75 years ofage shows a reduction in mortality in this age group, which is the goal of screening. In a recent statement, the Dutch Cancer Society did not advise breast self-examination for women in general, because a meta-analysis had not shown a reduction in mortality, irrespective of the positive findings on self-examination in many retrospective studies. However, breast self-examination may be advised to a small group of women with familial or hereditary breast cancer, especially carriers of the BRCA1 gene mutation, in whom a high percentage of rapidly proliferating grade III carcinomas are found.

[Guideline 'Treatment of breast cancer 2008' (revision)]. / Richtlijn 'Behandeling van het mammacarcinoom 2008' (herziening).

The Dutch evidence-based guideline 'Treatment of breast cancer' has been revised, and integrated with the guideline 'Screening for and diagnosis of breast cancer'. The guideline can be found on www. oncoline.nl and on www.cbo.nl. The Internet programme 'Adjuvant!' (www.adjuvantonline.com) can be used to predict both the prognosis and the efficacy of systemic adjuvant therapy for each patient. The indications for adjuvant chemotherapy and endocrine therapy have been widened. The aim is to reduce the absolute probability of death by at least 4-5% within 10 years. The goal of neoadjuvant chemotherapy in operable breast cancer is to enable breast-conserving therapy for large tumours in relatively small breasts. One could consider transferring responsibility for follow-up after 5 years from the hospital to the screening organisation following mastectomy, to the family doctor following breast-conserving therapy, and to an outpatient clinic for hereditary tumours in carriers of gene mutation. Cessation of follow-up above the age of 75 could also be considered.

[Neoadjuvant systemic therapy in patients with operable primary breast cancer: more benefits than breast-conserving therapy]. / Neoadjuvante systemische therapie bij het primair operabel mammacarcinoom: meer voordelen dan alleen borstsparende behandeling.

OBJECTIVE: To analyse the extent to which primary systemic therapy (PST) achieves the main goals in patients with operable primary breast cancer, these goals being breast-conserving therapy and pathological complete remission (pCR), and to evaluate the response. DESIGN: Retrospective. METHOD: In a retrospective analysis of 254 patients treated with PST in 2000-2007 in the Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, patients with inoperable disease (T4 and/or N3) were excluded. The response was mostly evaluated using contrast-enhanced MRI, whereby the chemotherapy regimen was switched if the reduction in the largest diameter of contrast washout was less than 25%. pCR was defined as no evidence of invasive cancer in the breast and axilla in the resection specimen. RESULTS: In patients with ductal carcinoma and lobular carcinoma an increase in breast-conserving therapy was seen in 32% and 17% of patients respectively. The pCR rate was 12% and 2% respectively. Secondary mastectomy because of irradical resection was required in 3% and 50% respectively. Multivariate analysis indicated that molecular type, defined on the basis of the expression of hormone receptors and human epidermal growth factor receptor 2 (HER2), i.e. luminal (oestrogen receptor-positive), basal (hormone receptor-negative and HER2-negative) and HER2-positive tumours treated with trastuzumab was the only independent predictor of pCR; 2%, 28% and 35% respectively (p=0.004). In 43 patients the chemotherapy regimen was adjusted because the tumour did not respond sufficiently. A favourable clinical response was observed in 72% (31/43) of these patients. CONCLUSION: The observed increase in the number of breast-conserving therapies after PST was clinically relevant. PST may be more effective when contrast-enhanced MRI is used for interim evaluation, based on which the treatment may be switched. There was a clear difference in histological and molecular types of tumour and therefore the choice of treatment may be adjusted accordingly.

[A solitary sternal lesion found by skeletal scintigraphy following treatment for breast carcinoma]. / Een solitaire sternumhaard op het skeletscintigram na behandeling wegens mammacarcinoom.

Breast carcinoma frequently metastasises to bone, most often to the thoracic and lumbosacral spine. 3 women, aged 66, 47 and 54 years, who had been previously treated for breast cancer presented with sternal pain. Bone scintigraphy revealed a solitary sternal hot spot in all 3 patients. In the final diagnosis, 1 patient had nonmalignant reactive changes, which required no further therapy; 1 patient had a bone metastasis, which was treated with radiation therapy and tamoxifen; and 1 patient had radionecrotic tissue, which was treated with hyperbaric oxygen therapy. Symptoms resolved in all 3 patients. Skeletal scintigraphy is the most sensitive method for detecting bone metastases, but it is not specific. Bone metastases are usually multifocal, but sometimes a solitary bone lesion is found. A solitary sternal metastasis must be differentiated from other sternal disorders. Various treatment options exist for patients who are ultimately diagnosed with a solitary sternal metastasis.

Impact of gene-expression profiling in patients with early breast cancer when applied outside the guideline directed indication area.

PURPOSE: In Dutch guidelines, gene expression profiles (GEP) are indicated in estrogen receptor positive early breast cancer patients in whom benefit of chemotherapy (CT) is uncertain based on traditional prognostic factors alone. Aim of the present study is to assess the use and impact of GEP on administration of adjuvant CT in breast cancer patients who have according to national guidelines a clear indication to either use or withhold adjuvant chemotherapy (clinical high or low risk). METHODS: Clinical low- and high-risk patients, according to Dutch breast cancer guidelines, diagnosed between 2011 and 2014 were selected from the Netherlands Cancer Registry. Influence of GEP use and GEP test result on CT administration was assessed with logistic regression. RESULTS: Overall, 26,425 patients were identified; 4.8% of patients with clinical low risk (444/9354), 7.5% of the patients with a clinical high risk (1281/17,071) received a GEP. GEP use was associated with significantly increased odds of CT administration in clinical low-risk patients (OR = 2.12 95% CI: 1.44-3.11). In clinical high-risk patients, GEP use was associated with a decreased frequency of CT administration (OR = 0.55, 95% CI: 0.48-0.63). Adherence to the GEP result was higher in clinical high-risk patients with a discordant GEP result as compared to clinical low-risk patients with a discordant GEP result: 71.7% vs. 52.2%, respectively. CONCLUSION: GEP is frequently used outside the indicated area and significantly influenced the administration of adjuvant CT, although adherence to the test result was limited.

An association study of established breast cancer reproductive and lifestyle risk factors with tumour subtype defined by the prognostic 70-gene expression signature (MammaPrint®).

BACKGROUND: Reproductive and lifestyle factors influence both breast cancer risk and prognosis; this might be through breast cancer subtype. Subtypes defined by immunohistochemical hormone receptor markers and gene expression signatures are used to predict prognosis of breast cancer patients based on their tumour biology. We investigated the association between established breast cancer risk factors and the 70-gene prognostication signature in breast cancer patients. PATIENTS AND METHODS: Standardised questionnaires were used to obtain information on established risk factors of breast cancer from the Dutch patients of the MINDACT trial. Clinical-pathological and genomic information were obtained from the trial database. Logistic regression analyses were used to estimate the associations between lifestyle risk factors and tumour prognostic subtypes, measured by the 70-gene MammaPrint® signature (i.e. low-risk or high-risk tumours). RESULTS: Of the 1555 breast cancer patients included, 910 had low-risk and 645 had high-risk tumours. Current body mass index (BMI), age at menarche, age at first birth, age at menopause, hormonal contraceptive use and hormone replacement therapy use were not associated with MammaPrint®. In parous women, higher parity was associated with a lower risk (OR: 0.75, [95% confidence interval {CI}: 0.59-0.95] P = 0.018) and longer breastfeeding duration with a higher risk (OR: 1.03, [95% CI: 1.01-1.05] P = 0.005) of developing high-risk tumours; risk estimates were similar within oestrogen receptor-positive disease. After stratifying by menopausal status, the associations remained present in post-menopausal women. CONCLUSION: Using prognostic gene expression profiles, we have indications that specific reproductive factors may be associated with prognostic tumour subtypes beyond hormone receptor status.

The incidence and significance of micrometastases in lymph nodes of patients with ductal carcinoma in situ and T1a carcinoma of the breast.

AIM: To report the incidence and predictive value of positive axillary nodes in ductal carcinoma in situ (DCIS) and T1a carcinoma of the breast. METHODS: Cases from The Netherlands Cancer Institute were used to determine the incidence of lymph-node metastases. All consecutive patients with primary breast cancer that were treated between 1989 and 1998 and who had undergone axillary dissection were selected. Patients were identified with pure DCIS (n = 71), DCIS with small invasion (n = 12), invasive ductal/lobular carcinoma (IDC/ILC) < or =5 mm (n = 18) or tubular carcinoma < or =10 mm (n = 17). All archived lymph nodes of these patients were re-evaluated using immunohistochemistry (IHC). RESULTS: In DCIS the incidence increased from 1.4% with routine staining to 11% with IHC. For DCIS with small invasion it was 0 vs 27%, respectively. In IDC/ILC sized 2-5 mm the incidence rose from 6 to 12% and in tubular carcinoma < or =10 mm from 0 to 12%. All but one of the immunohistochemically detected metastases were isolated tumour cells (n = 9) or small (micro)metastases (n = 4). Maximally two nodes per patient were affected. None of the patients with positive lymph nodes died during follow-up (mean 102 months). CONCLUSIONS: Survival of our patients appeared not to be influenced by the finding of micrometastases in the lymph nodes by IHC. Immunohistochemistry of the sentinel node seems not contributive to further treatment in these patients.