Population pharmacokinetics and exposure-response relationship of trastuzumab and bevacizumab in early-stage breast cancer.

AIMS: To describe the sources of interindividual variability of bevacizumab and trastuzumab pharmacokinetics in early-stage breast cancer, and to study the relationship between exposure and both early clinical response and specific adverse events. PATIENTS AND METHODS: Patients (n = 86) received 6 cycles of docetaxel + trastuzumab. Early tumour response was assessed by determination of the maximum standard uptake value (SUVmax) variation (ΔSUVmax) after 1 cycle using [18F]-fluorodeoxyglucose (FDG) PET. Early poor responders (ΔSUVmax < 70%) also received bevacizumab from cycle 3 to cycle 6. Sources of interindividual variability in pharmacokinetics of both antibodies were studied by population compartment modelling. Exposure as assessed by area under the concentration-versus-time curve (AUC) was compared between responders and non-responders and between patients experiencing specific adverse events or not. RESULTS: A two-compartment model described the pharmacokinetics of both antibodies satisfactorily. Their central volume of distributions (Vc) increased with body surface area and their elimination half-lives were shorter (~14 days) than previously reported (~26-28 days). There was a time-dependent increase in trastuzumab Vc, positively correlated to baseline SUVmax. Bevacizumab elimination rate (k10) was positively correlated with ΔSUVmax measured at the end of the first cycle. Bevacizumab had no significantly influence on trastuzumab pharmacokinetics. No relationship between exposure and clinical response or occurrence of adverse events was found. CONCLUSION: Tumour uptake as assessed by SUVmax influences the pharmacokinetics of bevacizumab and trastuzumab. In early-stage breast cancer, elimination half-lives of these therapeutic monoclonal antibodies may be shorter than those previously reported in more advanced disease.

Long-term survival in HER2-positive metastatic breast cancer treated with first-line trastuzumab: results from the french real-life curie database.

BACKGROUND: Outcome of HER2-positive metastatic breast cancer (MBC) patients has improved since the use of trastuzumab. However, most HER2-positive MBC patients will progress within 1 year of trastuzumab-based therapy. Only limited data are available concerning long-term responders. METHODS: The primary objective of this study was to compare overall survival (OS) of HER2+ MBC patients with long-term response to first-line trastuzumab with overall survival of those with non-long-term response, based on two institutional databases: the French Epidemiological Strategy and Medical Economics program and the Breast Database. Long-term responders (LTR) were defined as patients with non-progressive disease for ≥ 2 years on first-line trastuzumab. Secondary objectives included progression-free survival (PFS), and predictive factors for LTR status. RESULTS: From 2004 to 2014, 422 HER2-positive MBC patients received first-line trastuzumab. With a median follow-up of 48 months, median OS and PFS were 63 months (CI95%, 50-71), and 18 months (CI95%, 15-21) respectively. In 111 patients (26.3%) classified as LTR, median OS was 110 months (CI95%, 95-not reached) versus 56 months in non-LTR patients (CI95%, 47-68). In multivariate logistic regressions, the following factors were independently associated with LTR status: number of metastatic sites (≤ 2 versus > 2, p = 0.01); endocrine therapy for metastatic disease (p = 0.001) and taxane-based first-line chemotherapy (p = 0.003). CONCLUSION: Several features are associated with long-term response to trastuzumab: few metastatic sites, taxane-based chemotherapy and maintenance endocrine therapy in HR+ patients. Further studies are needed to identify patients in whom trastuzumab can be stopped after several years of sustained response.

A gene signature to predict high tumor-infiltrating lymphocytes after neoadjuvant chemotherapy and outcome in patients with triple-negative breast cancer.

Background: In patients with triple-negative breast cancer (TNBC), the extent of tumor-infiltrating lymphocytes (TILs) in the residual disease after neoadjuvant chemotherapy (NACT) is associated with better prognosis. Our objective was to develop a gene signature from pretreatment samples to predict the extent of TILs after NACT and then to test its prognostic value on survival. Patients and methods: Using 99 pretreatment samples, we generated a four-gene signature associated with high post-NACT TILs. Prognostic value of the signature on distant relapse-free survival (DRFS) was first assessed on the training set (n = 99) and then on an independent validation set (n = 115). Results: A four-gene signature combining the expression levels of HLF, CXCL13, SULT1E1, and GBP1 was developed in baseline samples to predict the extent of lymphocytic infiltration after NACT. In a multivariate analysis performed on the training set, this signature was associated with DRFS [hazard ratio (HR): 0.28, for a one-unit increase in the value of the four-gene signature, 95% confidence interval (CI): 0.13-0.63)]. In a multivariate analysis performed on an independent validation set, the four-gene signature was significantly associated with DRFS (HR: 0.17, 95% CI: 0.06-0.43). The four-gene signature added significant prognostic information when compared with the clinicopathologic pretreatment model (likelihood ratio test in the training set P = 0.004 and in the validation set P = 0.002). Conclusions: A four-gene signature predicts high levels of TILs after anthracycline-containing NACT and outcome in patients with TNBC and adds prognostic information to a clinicopathological model at diagnosis.

Trastuzumab versus observation for HER2 nonamplified early breast cancer with circulating tumor cells (EORTC 90091-10093, BIG 1-12, Treat CTC): a randomized phase II trial.

Background: Trastuzumab improves the outcome of women with HER2 positive breast cancer. We aimed to assess whether trastuzumab decreases the detection rate of circulating tumor cells (CTCs) in women with high risk, HER2 nonamplified, early breast cancer. Patients and methods: The EORTC 90091-10093 BIG 1-12 Treat CTC is a phase II trial, conducted in 70 hospitals and 6 CTC laboratories across 5 European countries. Patients with centrally confirmed HER2 nonamplified breast cancer and ≥1 centrally confirmed CTC per 15 ml of blood by CellSearch® following surgery and (neo)adjuvant chemotherapy were randomized (1 : 1) to 6 cycles of trastuzumab intravenously versus 18 weeks of observation. Randomization was stratified for center, locally confirmed estrogen receptor status and adjuvant versus neoadjuvant chemotherapy. The primary end point was rate of detection of ≥1 CTC per 15 ml of blood at week 18. Secondary end points were invasive disease-free survival (iDFS) and cardiac safety. Results: Between 30 April 2013 and 17 October 2016, 1317 patients were screened; 95 (7.2%) had detectable CTC(s), and 63 (4.8%) were randomized to trastuzumab (n = 31) or observation (n = 32). Fifty-eight patients were assessable for the primary end point, 29 in each arm. In 9 of the 58 patients, CTC(s) were still detected at week 18 : 5 in the trastuzumab and 4 in the observation arm (one-sided Fisher's exact test, P = 0.765). An Independent Data Monitoring Committee recommended stopping further accrual for futility for the primary end point. Median follow-up at database lock was 13 months (IQR 4-16.5). The 1-year iDFS was 93.8% (95% CI 77.3-98.4) in the observation versus 84.8% (95% CI 63.4-94.2) in the trastuzumab arm. No grade 2-4 cardiac events were observed in the trastuzumab arm. Conclusion: Trastuzumab does not decrease the detection rate of CTCs in HER2 nonamplified, nonmetastatic breast cancer.

Stromal lymphocyte infiltration after neoadjuvant chemotherapy is associated with aggressive residual disease and lower disease-free survival in HER2-positive breast cancer.

BACKGROUND: The role of tumor-infiltrating lymphocytes (TILs) in breast cancer has been extensively studied over the last decade. High TILs levels have been associated with pathological response rate in the neoadjuvant setting and with better outcomes in the adjuvant setting. However, little attention has been paid to changes in TILs and residual TIL levels after neoadjuvant chemotherapy (NAC). We investigated TIL levels before, after chemotherapy, and their dynamics during treatment; and we assessed the correlation of these levels with response to NAC and prognosis. MATERIALS AND METHODS: We identified 175 patients with primary HER2-positive breast cancers receiving NAC+/- trastuzumab between 2002 and 2011. Microbiopsy specimens and paired surgical samples were evaluated for stromal lymphocyte infiltration. Univariate and multivariate analyses were carried out to assess the association of clinical and pathological factors with pathological complete response (pCR) and disease-free survival. RESULTS: Baseline TIL levels were not significantly associated with pCR. TIL levels decreased during treatment in 78% of the patients. The magnitude of the decrease was strongly associated with pCR. After chemotherapy, TIL levels were high in tumors displaying aggressive patterns (high residual cancer burden score, mitotic index >22, tumor cellularity >5%). In the population with residual disease, TIL levels >25% at the end of NAC were significantly associated with an adverse outcome (TILs >25%, HR = 7.98, P = 0.009) after multivariate analyses including BMI, post-NAC mitotic index and tumor grade. CONCLUSION: A decrease in TIL levels during chemotherapy was positively associated with response to treatment. In tumor failing to achieve pCR, post-NAC lymphocytic infiltration was associated with higher residual tumor burden and adverse clinical outcome. Further studies are required to characterize immune infiltration in residual disease to identify candidates who could benefit from second-line therapy trials including immune checkpoint inhibitors.

Circulating tumor DNA changes for early monitoring of anti-PD1 immunotherapy: a proof-of-concept study.

BACKGROUND: Recent clinical results support the use of new immune checkpoint blockers (ICB), such as anti-PD-1 (e.g. nivolumab and pembrolizumab) and anti-PD-L1 antibodies. Radiological evaluation of ICB efficacy during therapy is challenging due to tumor immune infiltration. Changes of circulating tumor DNA (ctDNA) levels during therapy could be a promising tool for very accurate monitoring of treatment efficacy, but data are lacking with ICB. PATIENTS AND METHODS: This prospective pilot study was conducted in patients with nonsmall cell lung cancer, uveal melanoma, or microsatellite-instable colorectal cancer treated by nivolumab or pembrolizumab monotherapy at Institut Curie. ctDNA levels were assessed at baseline and after 8 weeks (w8) by bidirectional pyrophosphorolysis-activated polymerization, droplet digital PCR or next-generation sequencing depending on the mutation type. Radiological evaluation of efficacy of treatment was carried out by using immune-related response criteria. RESULTS: ctDNA was detected at baseline in 10 out of 15 patients. At w8, a significant correlation (r = 0.86; P = 0.002) was observed between synchronous changes in ctDNA levels and tumor size. Patients in whom ctDNA levels became undetectable at w8 presented a marked and lasting response to therapy. ctDNA detection at w8 was also a significant prognostic factor in terms of progression-free survival (hazard ratio = 10.2; 95% confidence interval 2.5-41, P < 0.001) and overall survival (hazard ratio = 15; 95% confidence interval 2.5-94.9, P = 0.004). CONCLUSION: This proof-of-principle study is the first to demonstrate that quantitative ctDNA monitoring is a valuable tool to assess tumor response in patients treated with anti-PD-1 drugs.

Circulating tumour cells and pathological complete response: independent prognostic factors in inflammatory breast cancer in a pooled analysis of two multicentre phase II trials (BEVERLY-1 and -2) of neoadjuvant chemotherapy combined with bevacizumab.

Background: We present a pooled analysis of predictive and prognostic values of circulating tumour cells (CTC) and circulating endothelial cells (CEC) in two prospective trials of patients with inflammatory breast cancer (IBC) treated with neoadjuvant chemotherapy combined with neoadjuvant and adjuvant bevacizumab. Patients and methods: Nonmetastatic T4d patients were enrolled in two phase II multicentre trials, evaluating bevacizumab in combination with sequential neoadjuvant chemotherapy of four cycles of FEC followed by four cycles of docetaxel in HER2-negative tumour (BEVERLY-1) or docetaxel and trastuzumab in HER2-positive tumour (BEVERLY-2). CTC and CEC were detected in 7.5 and 4 ml of blood, respectively, with the CellSearch System. Results: From October 2008 to September 2010, 152 patients were included and 137 were evaluable for CTC and CEC. At baseline, 55 patients had detectable CTC (39%). After four cycles of chemotherapy, a dramatic drop in CTC to a rate of 9% was observed (P < 0.01). Pathological complete response (pCR) rate was 40%. No correlation was found between CTC or CEC levels and pCR rate. Median follow-up was 43 months. CTC detection (≥1 CTC/7.5 ml) at baseline was associated with shorter 3-year disease-free survival (39% versus 70% for patients without CTC, P < 0.01, HR 2.80) and shorter 3-year overall survival (OS) (P < 0.01). In multivariate analysis, independent prognostic parameters for shorter survival were absence of hormonal receptors, no pCR and CTC detection at baseline. CEC level at baseline or variations during treatment had no prognostic value. Conclusion: In this pooled analysis of two prospective trials in nonmetastatic IBC, detection rate of CTC was 39% with a strong and independent prognostic value for survival. Combination of pCR after neoadjuvant treatment with no CTC detection at baseline isolated a subgroup of IBC with excellent OS (94% 3-year OS), suggesting that CTC count could be part of IBC stratification in prospective trials.

Prediction of long-term cumulative incidences based on short-term parametric model for competing risks: application in early breast cancer.

Use of parametric statistical models can be a solution to reduce the follow-up period time required to estimate long-term survival. Mould and Boag were the first to use the lognormal model. Competing risks methodology seems more suitable when a particular event type is of interest than classical survival analysis. The objective was to evaluate the ability of the Jeong and Fine model to predict long-term cumulative incidence. Survival data recorded by Institut Curie (Paris) from 4761 breast cancer patients treated and followed between 1981 and 2013 were used. Long-term cumulative incidence rates predicted by the model using short-term follow-up data were compared to non-parametric estimation using complete follow-up data. 20- or 25-year cumulative incidence rates for loco-regional recurrence and distant metastasis predicted by the model using a maximum of 10 years of follow-up data had a maximum difference of around 6 % compared to non-parametric estimation. Prediction rates were underestimated for the third and composite event (contralateral or second cancer or death). Predictive ability of Jeong and Fine model on breast cancer data was generally good considering the short follow-up period time used for the estimation especially when a proportion of patient did not experience loco-regional recurrence or distant metastasis.

Prognostic impact of discrepant Ki67 and mitotic index on hormone receptor-positive, HER2-negative breast carcinoma.

BACKGROUND: Inconsistencies between mitotic index (MI) and Ki67 measures have been identified in many breast tumour samples. The aim of this study was to describe the prognosis of hormone receptor-positive (HR+) HER2- tumours having discrepant MI and Ki67. METHODS: We included a cohort of breast cancer patients initially treated by surgery between 2001 and 2005 in the Institut Curie. Breast cancer-specific survival (BCSS) and disease-free survival (DFS) were analysed according to three proliferation groups: high MI/high Ki67 (MI=3, Ki67>20%), low MI/low Ki67 (MI<3, Ki67⩽20%) and discrepant (high MI/low Ki67 or low MI/high Ki67). RESULTS: Among the 1430 patients, 19.6% had discrepant Ki67 and MI, 11.6% had high markers and 68.8% had low markers. The 5-year BCSS was 95.8%, 95% CI (0.93-0.98) in the discrepant group, 99.3%, 95% CI (0.993-0.999) in the low-proliferation group and 91.8%, 95% CI (0.88-0.96) in the high-proliferation group. In multivariate analysis, the survival of the discrepant group was lower than that of the low-proliferation group: BCSS hazard ratio (HR)=3.01 (1.32-6.84; P=0.008) and DFS HR=2.07, 95% CI (1.31-3.26; P=0.002). Among grade 2 tumours in multivariate analysis, DFS of the discrepant group was lower than that of the low MI/low Ki67 group: HR=1.98, 95% CI (1.14-3.46), P=0.02. Regarding BCSS, the obtained results were similar. CONCLUSION: The prognosis of patients with discrepant MI and Ki67 appears intermediate between that of low MI/low Ki67 and high MI/high Ki67 groups. These markers should be jointly analysed to clarify prognosis.

Are we able to predict survival in ER-positive HER2-negative breast cancer? A comparison of web-based models.

BACKGROUND: Several prognostic models have been proposed and demonstrated to be predictive of survival outcomes in breast cancer. In the present article, we assessed whether three of these models are comparable at an individual level. METHODS: We used a large data set (n=965) of women with hormone receptor-positive and HER2-negative early breast cancer from the public data set of the METABRIC (Molecular Taxonomy of Breast Cancer International Consortium) study. We compared the overall performance of three validated web-based models: Adjuvant!, CancerMath.net and PREDICT, and we assessed concordance of these models in 10-year survival prediction. RESULTS: Discrimination performances of the three calculators to predict 10-year survival were similar for the Adjuvant! Model, 0.74 (95% CI 0.71-0.77) for the Cancermath.net model and 0.72 (95% CI 0.69-0.75) for the PREDICT model). Calibration performances, assessed graphically, were satisfactory. Predictions were concordant and stable in the subgroup, with a predicted survival higher than 90% with a median score dispersion at 0.08 (range 0.06-0.10). Dispersion, however, reached 30% for the subgroups with a predicted survival between 10 and 50%. CONCLUSION: This study revealed that the three web-based predictors equally perform well at the population level, but exhibit a high degree of discordance in the intermediate and poor prognosis groups.

Time-varying effect and long-term survival analysis in breast cancer patients treated with neoadjuvant chemotherapy.

BACKGROUND: Recent studies have indicated the prognostic value of tumour subtype and pathological complete response (pCR) after neoadjuvant chemotherapy (NAC). However these results were reported after a short follow-up and using a standard Cox model which could be unsatisfactory for time-dependent factors. In the present study, we identified the prognostic factors for long-term outcome after NAC, considering that they could have an inconstant impact over time. METHODS: Prognostic factors from 956 consecutive breast cancer patients treated with NAC were identified and associated with long-term outcomes. We estimated survival by a time function multivariate Cox model regression and stratified by follow-up length. RESULTS: The prognostic value of tumour histological grade and hormone receptors status varied as distant recurrence-free interval (DRFI) increased. The multivariate analysis identified the following significant prognostic factors: tumour size, N stage, clinical and pathological response to NAC, hormone receptors (HR) status and histological tumour grade. The 'prognostic benefit' of low-grade and positive-HR status decreased over the years. Thus, in the early years after cancer diagnosis, the hazard ratio of distant recurrences in patients with positive-HR status increased from 0.26 (95% CI 0.1-0.4) at 6 months to 2.2 (95% CI 1.3-3.7) at 120 months. The histological tumour grade followed a similar trend. The hazard ratio of grade III patients compared with grade I was 1.83 (95% CI 1.1-2.8) at 36 months and diminished over time to 0.70 (95% CI 0.4-1.3) at 120 months. This indicates that the risk of recurrence for positive-HR patients was 74% lower at 6 months compared with the negative-hormone receptor group, but 30% higher at 5 years and more than double at 10 years. High-grade tumours presented a risk of 83% in the earlier years decreasing to 30% at 10 years versus the low-grade group. CONCLUSION: From the present study, we conclude the importance of identifying time-dependent prognostic factors. Distant recurrence-free interval within women who receive NAC are influenced by achieving pCR and breast cancer subtype. Tumours with more aggressive biology have poorer survival during the first 5 years, but if they exceed this point their prognostic impact is no longer significant. Conversely, positive-HR patients remain at risk for distant recurrence for many years.

Phase II randomized study of whole-brain radiation therapy with or without concurrent temozolomide for brain metastases from breast cancer.

BACKGROUND: To improve the therapeutic index of whole-brain radiation therapy (WBRT) in the treatment of brain metastases (BM) from breast cancer, we investigated the efficacy and safety of WBRT combined with temozolomide (TMZ) in this population. PATIENTS AND METHODS: This phase II multicenter prospective randomized study included patients with newly diagnosed intraparenchymal BMs from breast cancer, unsuitable for surgery or radiosurgery. All patients received conformal WBRT (3 Gy × 10-30 Gy), with or without concomitant TMZ administered at a dosage of 75 mg/m(2)/day during the irradiation period. The primary end point was objective response rate (ORR) 6 weeks after the end of treatment, defined as a partial or complete response on systematic brain MRI (modified WHO criteria). Secondary end points were progression-free survival (PFS) and overall survival (OS), neurologic symptoms, and tolerability. RESULTS: Between February 2008 and November 2010, 100 patients were enrolled in the study (50 in the WBRT + TMZ arm, 50 in the WBRT arm). Median age was 55 years (29-79). Median follow-up was 9.4 months [1.0-68.1]. ORRs at 6 weeks were 36% in the WBRT arm and 30% in the WBRT + TMZ arm (NS). In the WBRT arm, median PFS was 7.4 months and median OS was 11.1 months. In the WBRT + TMZ arm, median PFS was 6.9 months and median OS was 9.4 months. Treatment was well tolerated in this arm: the most common ≥grade 2 acute toxicity was reversible lymphopenia. CONCLUSION: WBRT combined with TMZ did not significantly improve local control and survival in patients with BMs from breast cancer. CLINICALTRIALS.GOV: NCT00875355.

UNICANCER-PEGASE 07 study: a randomized phase III trial evaluating postoperative docetaxel-5FU regimen after neoadjuvant dose-intense chemotherapy for treatment of inflammatory breast cancer.

BACKGROUND: Inflammatory breast cancer (IBC) is a rare and aggressive disease requiring a multimodal treatment. We evaluated the benefit of adding docetaxel-5-fluorouracil (D-5FU) regimen after preoperative dose-intense (DI) epirubicin-cyclophosphamide (EC) and locoregional treatment in IBC patients. PATIENTS AND METHODS: PEGASE 07 was a national randomized phase III open-label study involving 14 hospitals in France. Women with nonmetastatic IBC were eligible and randomly assigned to receive either four cycles of DI EC (E 150 mg/m(2) and C 4000 mg/m(2) every 3 weeks with repeated hematopoietic stem cell support), then mastectomy with axillary lymph node dissection, and radiotherapy (arm A) or the same treatment followed by four cycles of D-5FU (D 85 mg/m(2), day 1 and 5FU 750 mg/m(2)/day continuous infusion, days 1-5 every 3 weeks) administered postradiotherapy (arm B). Patients with hormone receptor-positive tumors received hormonal therapy. Disease-free survival (DFS) was the primary end point. Secondary end points included tolerance, pathological complete response (pCR) rate, and overall survival (OS). RESULTS: Between January 2001 and May 2005, 174 patients were enrolled and treated (87 in each arm). Median follow-up was similar in both arms: 59.6 months [95% confidence interval (CI) 58.4-60.3] in arm A and 60.5 months (95% CI 58.3-61.4) in arm B. The estimated 5-year DFS rates were not different: 55% (95% CI 43.9-64.7) in arm A and 55.5% (95% CI 44.3-65.3) in arm B [hazard ratio (HR) = 0.94 (0.61-1.48); P = 0.81]. Identical results were observed for 5-year OS: 70.2% (95% CI 59.1-78.8) in arm A and 70% (95% CI 58.8-78.7) in arm B [HR = 0.93 (0.55-1.60); P = 0.814]. Following DI EC induction, in-breast and global (breast plus nodes) pCR were 28.9% and 20.1%, respectively. Estrogen receptor and pCR status were independently associated with survival. CONCLUSION: The addition of D-5FU after preoperative DI EC and standard local therapy did not improve DFS in IBC. CLINICAL TRIAL NUMBER: ClinicalTrials.gov identifier: NCT02324088.

Response to dual HER2 blockade in a patient with HER3-mutant metastatic breast cancer.

BACKGROUND: HER3 activating mutations have been shown in preclinical models to be oncogenic and ligand-independent, but to depend on kinase-active HER2. PATIENTS AND METHODS: Whole-exome sequencing of the primary HER2-negative breast cancer and its HER2-negative synchronous liver metastasis from a 46-year-old female revealed the presence of an activating and clonal HER3 G284R mutation. RESULTS: HER2 dual blockade with trastuzumab and lapatinib as third-line therapy led to complete metabolic response in 2 weeks and confirmed radiological partial response after 8 weeks. Following the resection of the liver metastasis, the patient remains disease-free 40 weeks after initiation of the HER2 dual blockade therapy. Immunohistochemical analysis demonstrated a substantial reduction of phospho-rpS6 and phospho-AKT in the post-therapy biopsy of the liver metastasis. DISCUSSION: This is the first-in-man evidence that anti-HER2 therapies are likely effective in breast cancers harboring HER3 activating mutations.

Histological grade concordance between diagnostic core biopsy and corresponding surgical specimen in HR-positive/HER2-negative breast carcinoma.

BACKGROUND: The identification and validation of suitable predictive and prognostic factors are a challenge to improve the treatment scheme selection. Discordances in histological grade can be established between core biopsy and surgical specimens. This is important in HR-positive/HER2-negative subgroup where histological grade identifies patients at high risk and is a strong determinant for treatment scheme. METHODS: A total of 350 consecutive invasive breast carcinoma biopsies were assessed and compared with surgical specimens in Institut Curie, Paris, France. Clinical, radiological and pathological data were recorded. RESULTS: Histological grade concordance rate in the HR+/HER2- group was 75%. A grade underestimation was mainly due to mitotic index misgrading (23%). Large tumours (P<0.05), premenopausal patients (P=0.005) and non-ultrasound-guided biopsies (P=0.04) were risk factors for misgrading. The highest discordance was found in tumours that required chemotherapy (39%, P<0.05), and it was related to an underestimation of histological grade on core biopsies (94%). CONCLUSIONS: Histological grade in HR+/HER2- group is important to identify patients with poor prognosis and start a systemic therapy. Histological grade discordance was correlated with an underestimation of mitotic index and factors probably associated with intratumor heterogeneity (premenopausal status, tumour size and the type of core biopsy performed). But such discordance did not appear to modify the therapeutic decision, because systemic treatment decision-making also integrates other variables. Determining histological grade in core biopsy can be especially important in HR-positive/HER2-negative subgroup where it identifies patients at high risk and is a strong determinant of the treatment scheme.

Trastuzumab duration effects within patient prognostic subgroups in the PHARE trial.

BACKGROUND: At 42.5 months of median follow-up, PHARE failed to show that 6 was non-inferior to 12 months of adjuvant trastuzumab. From the results of PHARE, questions remain regarding whether the magnitude of benefit derived from 1 year is sufficient to justify its systematic use for different patient subgroups. METHODS: Treatment effects were evaluated according to various tumour characteristics, and the multivariate Cox proportional hazards regression models were carried out on metastases-free survival (MFS) in the 12 months control arm. A prognostic score was defined providing the identification of patient categories with similar risks. The 6-month arm was used as a validation set in order to test for heterogeneity. This study is registered at clinicaltrials.gov, number NCT00381901. RESULTS: A total of 261 metastatic events were observed and four prognostic groups were defined: very low, low, intermediate and high risk in the 12-month arm. The corresponding 3-year MFS rates were 98.3%, 95.8%, 90.4% and 78.4% in the four prognostic groups, respectively. In the 6-month arm, the 3-year MFS rates were 98.3%, 94.2%, 85.7% and 74.8% in the four prognostic groups, respectively. CONCLUSION: In the very low-risk group, the potential absolute benefit of standard duration of trastuzumab was small enough to indicate that optimal standard treatment might be clinically questionable. On the other hand, the 3-year metastasis occurrence rates strongly support the need for a search of a more efficient treatment in the low-, intermediate- and high-risk groups.

Concurrent administration of trastuzumab with locoregional breast radiotherapy: long-term results of a prospective study.

This single-center prospective study aims to assess the outcomes and the toxicities related to the concurrent administration of trastuzumab (T) with adjuvant locoregional radiotherapy (RT) in localized breast cancer. Data of 308 patients were analyzed. T was delivered every 3 weeks (loading dose of 8 mg/kg, then 6 mg/kg) for 1 year. Left ventricular ejection fraction (LVEF), measured by echocardiography or myocardial scintigraphy, was considered as impaired when below 55%. Toxicities were assessed according to the Common Terminology Criteria for Adverse Events version 3.0. Univariate and multivariate analyses were carried out using the Cox model. Median follow-up was 50.2 months (13.0-126.0). Median age at diagnosis was 52 years (25-83). Internal mammary node (IMN) RT was performed in 227 patients (73.7%). After completion of RT, 26 patients (8.4%) presented an impaired LVEF: 17 (5.5%) of grade 1, 7 (2.3%) of grade 2, and 2 (0.6%) of grade 3. At 48 months, locoregional control rate was 95% [95% CI 92; 98], and overall survival rate was 98% [95% CI 96; 100]. In univariate analysis, neither the treated breast side (p = 0.655) nor IMN RT (p = 0.213) exposed patients to LVEF alteration. In multivariate analysis, clinical lymph node involvement was associated with an increased risk of locoregional and distant recurrence (p = 0.016 and p = 0.007, respectively). In this prospective study, the toxicities of concurrent T with locoregional breast RT were acceptable and the outcomes favorable. Longer follow-up is warranted to confirm these results.

Outcome impact of PIK3CA mutations in HER2-positive breast cancer patients treated with trastuzumab.

BACKGROUND: Phosphatidylinositol 3-kinase (PI3K) pathway activation has been suggested to negatively influence response to anti-HER2 therapy in breast cancer patients. The present study focused on mutations of the PIK3CA gene, encoding one of the two PI3K subunits. METHODS: PIK3CA mutations were assessed by direct sequencing in 80 HER2-positive patients treated with 1 year of trastuzumab. All patients preoperatively received four cycles of anthracycline-based chemotherapy, followed by four cycles of docetaxel and 1 year of trastuzumab, starting either before surgery with the first cycle of docetaxel and continuing after surgery (neoadjuvant trastuzumab arm, n=43), or only after surgery (adjuvant trastuzumab arm, n=37). RESULTS: PIK3CA mutations were found in 17 tumours (21.3%). Better disease-free survival (DFS) was observed in patients with PIK3CA wild-type compared with mutated tumours (P=0.0063). By combining PIK3CA status and treatment arms, four separate prognostic groups with significantly different DFS (P=0.0013) were identified. CONCLUSION: These results confirm that the outcome of HER2-positive patients treated with trastuzumab is significantly worse in patients with PIK3CA-mutated compared with wild-type tumours.

Unbiased quantitative assessment of Her-2 expression of circulating tumor cells in patients with metastatic and non-metastatic breast cancer.

Background Circulating tumor cells (CTCs) can provide the basis for a liquid biopsy and may guide the use of targeted therapies. We report on unbiased quantification of Her-2 protein expression of CTCs. Patients and methods Her-2 assessment of CTCs was carried out using the CellSearch(®) system in 103 metastatic (M1) and 88 non-metastatic (M0) breast-cancer patients. Expression of Her-2 on CTCs was determined by a manual review and an automated algorithm using Her-2- fluorescein isothiocyanate (FITC) fluorescence of leukocytes to determine the Her-2-expression threshold in each sample. Results Her-2 expression of CTCs varied greatly within and among patients compared with Her-2 expression of leukocytes. In M1 patients, a threshold of 75% of Her-2 positive CTCs in patients with ≥5 CTCs was set. Applying this threshold, 9% of M1 patients with Her-2-negative primary tumors had Her-2-positive CTC status and 29% of M1 patients with Her-2-positive primary tumors had Her-2-negative CTC status. No Her-2 discrepancy was observed between CTCs and primary tumors in M0 patients. Conclusions Our findings demonstrate that Her-2 expression is heterogeneous among CTCs within each patient. We show the feasibility of unbiased quantitative and reproducible assessment of treatment targets on CTCs, opening a path towards personalized treatment.