Prognostic value of EndoPredict test in patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative primary breast cancer screened for the randomized, double-blind, phase III UNIRAD trial

BACKGROUND

The purpose of this study was to evaluate the prognostic value of the multigene EndoPredict test in prospectively collected data of patients screened for the randomized, double-blind, phase III UNIRAD trial, which evaluated the addition of everolimus to adjuvant endocrine therapy in high-risk, hormone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative early breast cancer.

PATIENTS AND METHODS

Patients were classified into low or high risk according to the EPclin score, consisting of a 12-gene molecular score combined with tumor size and nodal status. Association of the EPclin score with disease-free survival (DFS) and distant metastasis-free survival (DMFS) was evaluated using Kaplan-Meier estimates. The independent prognostic added value of EPclin score was tested in a multivariate Cox model after adjusting on tumor characteristics.

RESULTS

EndoPredict test results were available for 768 patients: 663 patients classified as EPclin high risk (EPCH) and 105 patients as EPclin low risk (EPCL). Median follow-up was 70 months (range 1-172 months). For the 429 EPCH randomized patients, there was no significant difference in DFS between treatment arms. The 60-month relapse rate for patients in the EPCL and EPCH groups was 0% and 7%, respectively. Hazard ratio (HR) supposing continuous EPclin score was 1.87 [95% confidence interval (CI) 1.4-2.5, P < 0.0001]. This prognostic effect remained significant when assessed in a Cox model adjusting on tumor size, number of positive nodes and tumor grade (HR 1.52, 95% CI 1.09-2.13, P = 0.0141). The 60-month DMFS for patients in the EPCL and EPCH groups was 100% and 94%, respectively (adjusted HR 8.10, 95% CI 1.1-59.1, P < 0.0001).

CONCLUSIONS

The results confirm the value of EPclin score as an independent prognostic parameter in node-positive, hormone receptor-positive, HER2-negative early breast cancer patients receiving standard adjuvant treatment. EPclin score can be used to identify patients at higher risk of recurrence who may warrant additional systemic treatments.

Results of the c-TRAK TN trial: a clinical trial utilising ctDNA mutation tracking to detect molecular residual disease and trigger intervention in patients with moderate- and high-risk early-stage triple-negative breast cancer

BACKGROUND

Post-treatment detection of circulating tumour DNA (ctDNA) in early-stage triple-negative breast cancer (TNBC) patients predicts high risk of relapse. c-TRAK TN assessed the utility of prospective ctDNA surveillance in TNBC and the activity of pembrolizumab in patients with ctDNA detected [ctDNA positive (ctDNA+)].

PATIENTS AND METHODS

c-TRAK TN, a multicentre phase II trial, with integrated prospective ctDNA surveillance by digital PCR, enrolled patients with early-stage TNBC and residual disease following neoadjuvant chemotherapy, or stage II/III with adjuvant chemotherapy. ctDNA surveillance comprised three-monthly blood sampling to 12 months (18 months if samples were missed due to coronavirus disease), and ctDNA+ patients were randomised 2 : 1 to intervention : observation. ctDNA results were blinded unless patients were allocated to intervention, when staging scans were done and those free of recurrence were offered pembrolizumab. A protocol amendment (16 September 2020) closed the observation group; all subsequent ctDNA+ patients were allocated to intervention. Co-primary endpoints were (i) ctDNA detection rate and (ii) sustained ctDNA clearance rate on pembrolizumab (NCT03145961).

RESULTS

Two hundred and eight patients registered between 30 January 2018 and 06 December 2019, 185 had tumour sequenced, 171 (92.4%) had trackable mutations, and 161 entered ctDNA surveillance. Rate of ctDNA detection by 12 months was 27.3% (44/161, 95% confidence interval 20.6% to 34.9%). Seven patients relapsed without prior ctDNA detection. Forty-five patients entered the therapeutic component (intervention n = 31; observation n = 14; one observation patient was re-allocated to intervention following protocol amendment). Of patients allocated to intervention, 72% (23/32) had metastases on staging at the time of ctDNA+, and 4 patients declined pembrolizumab. Of the five patients who commenced pembrolizumab, none achieved sustained ctDNA clearance.

CONCLUSIONS

c-TRAK TN is the first prospective study to assess whether ctDNA assays have clinical utility in guiding therapy in TNBC. Patients had a high rate of metastatic disease on ctDNA detection. Findings have implications for future trial design, emphasising the importance of commencing ctDNA testing early, with more sensitive and/or frequent ctDNA testing regimes.

Overall survival in the OlympiA phase III trial of adjuvant olaparib in patients with germline pathogenic variants in BRCA1/2 and high risk, early breast cancer

BACKGROUND

The randomized, double-blind OlympiA trial compared 1 year of the oral poly(adenosine diphosphate-ribose) polymerase inhibitor, olaparib, to matching placebo as adjuvant therapy for patients with pathogenic or likely pathogenic variants in germline BRCA1 or BRCA2 (gBRCA1/2pv) and high-risk, human epidermal growth factor receptor 2-negative, early breast cancer (EBC). The first pre-specified interim analysis (IA) previously demonstrated statistically significant improvement in invasive disease-free survival (IDFS) and distant disease-free survival (DDFS). The olaparib group had fewer deaths than the placebo group, but the difference did not reach statistical significance for overall survival (OS). We now report the pre-specified second IA of OS with updates of IDFS, DDFS, and safety.

PATIENTS AND METHODS

One thousand eight hundred and thirty-six patients were randomly assigned to olaparib or placebo following (neo)adjuvant chemotherapy, surgery, and radiation therapy if indicated. Endocrine therapy was given concurrently with study medication for hormone receptor-positive cancers. Statistical significance for OS at this IA required P < 0.015.

RESULTS

With a median follow-up of 3.5 years, the second IA of OS demonstrated significant improvement in the olaparib group relative to the placebo group [hazard ratio 0.68; 98.5% confidence interval (CI) 0.47-0.97; P = 0.009]. Four-year OS was 89.8% in the olaparib group and 86.4% in the placebo group (Δ 3.4%, 95% CI -0.1% to 6.8%). Four-year IDFS for the olaparib group versus placebo group was 82.7% versus 75.4% (Δ 7.3%, 95% CI 3.0% to 11.5%) and 4-year DDFS was 86.5% versus 79.1% (Δ 7.4%, 95% CI 3.6% to 11.3%), respectively. Subset analyses for OS, IDFS, and DDFS demonstrated benefit across major subgroups. No new safety signals were identified including no new cases of acute myeloid leukemia or myelodysplastic syndrome.

CONCLUSION

With 3.5 years of median follow-up, OlympiA demonstrates statistically significant improvement in OS with adjuvant olaparib compared with placebo for gBRCA1/2pv-associated EBC and maintained improvements in the previously reported, statistically significant endpoints of IDFS and DDFS with no new safety signals.

Five-fraction Radiotherapy for Breast Cancer: FAST-Forward to Implementation

INTRODUCTION

The phase 3 FAST-Forward trial reported outcomes for 26 and 27 Gy schedules delivered in 5 fractions over 1 week versus 40 Gy in 15 fractions over 3 weeks in 4000 patients. We discuss concerns raised by the radiotherapy community in relation to implementing this schedule.

IPSILATERAL BREAST TUMOUR RELAPSE (IBTR)

Published estimated 5-year IBTR with 95% CI after 40 Gy in 15 fractions was 2.1% (95% CI 1.4-3.1), 1.7% (1.2-1.6) after 27 Gy and 1.4% (0.2-2.2) after 26 Gy, emphatically showing non-inferiority of the 5-fraction regimens. Subgroup analyses comparing IBTR in 26 Gy versus 40 Gy show no evidence of differential effect regarding age, grade, pathological tumour size, nodal status, tumour bed boost, adjuvant chemotherapy, HER2 status and triple negative status. The number of events in these analyses is small and results should be interpreted with caution. There was only 1 IBTR event post-mastectomy.

NORMAL TISSUE EFFECTS

The 26 Gy schedule, on the basis of similar NTE to 40 Gy in 15 fractions, is the recommended regimen for clinical implementation. There is a low absolute rate of moderate/marked NTE, these are predominantly moderate not severe change. Subgroup analyses comparing clinician-assessed moderate or marked adverse effect for 26 Gy versus 40 Gy show no evidence of differential effects according to age, breast size, surgical deficit, tumour bed boost, or adjuvant chemotherapy.

RADIOBIOLOGICAL CONSIDERATIONS

The design of the FAST-Forward trial does not control for time-related effects, and the ability to interpret clinical outcomes in terms of underlying biology is limited. There could conceivably be a time-effect for tumour control. A slight reduction in α/β estimate for the late normal tissue effects of test regimens might be a chance effect, but if real could reflect fewer consequential late effects due to lower rates of moist desquamation.

CONCLUSION

The 26 Gy 5-fraction daily regimen for breast radiotherapy can be implemented now.

Assessment of structural chromosomal instability phenotypes as biomarkers of carboplatin response in triple negative breast cancer: the TNT trial

BACKGROUND

In the TNT trial of triple negative breast cancer (NCT00532727), germline BRCA1/2 mutations were present in 28% of carboplatin responders. We assessed quantitative measures of structural chromosomal instability (CIN) to identify a wider patient subgroup within TNT with preferential benefit from carboplatin over docetaxel.

PATIENTS AND METHODS

Copy number aberrations (CNAs) were established from 135 formalin-fixed paraffin-embedded primary carcinomas using Illumina OmniExpress SNP-arrays. Seven published [allelic imbalanced CNA (AiCNA); allelic balanced CNA (AbCNA); copy number neutral loss of heterozygosity (CnLOH); number of telomeric allelic imbalances (NtAI); BRCA1-like status; percentage of genome altered (PGA); homologous recombination deficiency (HRD) scores] and two novel [Shannon diversity index (SI); high-level amplifications (HLAMP)] CIN-measurements were derived. HLAMP was defined based on the presence of at least one of the top 5% amplified cytobands located on 1q, 8q and 10p. Continuous CIN-measurements were divided into tertiles. All nine CIN-measurements were used to analyse objective response rate (ORR) and progression-free survival (PFS).

RESULTS

Patients with tumours without HLAMP had a numerically higher ORR and significantly longer PFS in the carboplatin (C) than in the docetaxel (D) arm [56% (C) versus 29% (D), PHLAMP,quiet = 0.085; PFS 6.1 months (C) versus 4.1 months (D), Pinteraction/HLAMP = 0.047]. In the carboplatin arm, patients with tumours showing intermediate telomeric NtAI and AiCNA had higher ORR [54% (C) versus 20% (D), PNtAI,intermediate = 0.03; 62% (C) versus 33% (D), PAiCNA,intermediate = 0.076]. Patients with high AiCNA and PGA had shorter PFS in the carboplatin arm [3.4 months (high) versus 5.7 months (low/intermediate); and 3.8 months (high) versus 5.6 months (low/intermediate), respectively; Pinteraction/AiCNA = 0.027, Padj.interaction/AiCNA = 0.125 and Pinteraction/PGA = 0.053, Padj.interaction/PGA = 0.176], whilst no difference was observed in the docetaxel arm.

CONCLUSIONS

Patients with tumours lacking HLAMP and demonstrating intermediate CIN-measurements formed a subgroup benefitting from carboplatin relative to docetaxel treatment within the TNT trial. This suggests a complex and paradoxical relationship between the extent of genomic instability in primary tumours and treatment response in the metastatic setting.

Abstract P4-13-13: Meta-analyses of visceral versus non-visceral metastases treated by AI & SERD agents as 2nd line endocrine therapy (ET) for HR+ breast cancer (BC)

There is a prevailing belief that ET for HR+ advanced BC is not as effective in patients with visceral metastases (VM) compared to non-visceral metastases (nVM), particularly with later lines of ET. Recently fulvestrant 500mg (Ful 500), has been reported to have greater efficacy in nVM compared to i) VM treated by Ful 500 but also compared to ii) nVM treated by Ful 250 (2nd line) and iii) nVM treated by aromatase inhibitor (AI), anastrozole (1st Line) – implying both site and agent related efficacy. Absence of significant overall survival (OS) difference in PALOMA 3 (2nd line) has increased the debate regarding when to add CDK 4/6is to ET, especially given the OS advantage for Ful 500 monotherapy in the 1st & 2nd line settings.

Patients & Methods: Anonymised, individual patient level data was obtained from randomised controlled trials (RCTs) involving AI & SERD used as mono-theraphy in 2nd or 3rd Line setting in known HR+ BC. All the trials were Phase 3 double-blind, placebo RCTs. All were rigorously assessed for clinical benefit (CB), progression free survival (PFS), duration of CB (DoCB) and OS. Details of the studies, types of ET and patient numbers are shown in the Table.

Results: Outcome data is presented for each study and then summarised under AI, SERD (Ful 250 or 500) and 'all Ets combined'. Odds ratios (Ors) & hazard ratios (HRs) for VM versus nVM by endocrine agents are shown in the Table.

AgentStudyTotal Pats.HR+ Pats.CBRPFSOSDoCBAI(n)(n)OR (95%Cis)HR (95%Cis)HR (95%Cis)HR (95%Cis)Exe00202301831.181.441.271.50Exe00211931681.151.951.832.12AnaEFECT3403360.941.521.201.10AnaSOFEA2492491.291.181.051.41subtotal7636871.11 (0.84-1.48)1.47*** (1.22-1.79)1.21* (1.01-1.45)1.43** (1.10-1.86)SERDFul 25000202191601.791.701.401.23Ful 25000212041771.281.811.322.06Ful 250EFECT3513450.791.401.311.03Ful 250SOFEA2312310.701.171.242.22Ful 250CONFIRM1521521.131.071.510.84Subtotal9268341.05 (0.75-1.45)1.39*** (1.16-1.67)1.34*** (1.14-1.57)1.36 (0.93-1.98)SERDFul 500CONFIRM1441442.24 (1.12-4.48)1.30 (0.90-1.87)1.33 (1.14-1.57)0.97 (0.55-1.66)All ETsTotal183316651.13 (0.92-1.39)1.42*** (1.26-1.59)1.28*** (1.14-1.44)1.35** (1.09-1.66)

[Pats=Patients; (n)=number; CBR-Clinical Benefit Rate; p-values p&lt;0.05*, p&lt;0.01**, p&lt;0.001***]

Median PFS (months) for nVM for AI, SERD250, SERD500 & ‘all Ets combined’ were 5.4, 5.5, 11.0 & 5.5 respectively: for VM they were 2.9, 3.5, 5.5 & 3.2 respectively.

Median OS (months) for nVM for AI, SERD250, SERD500 & ‘all Ets combined’ was 24.2, 26.0, 35.4 & 25.4 respectively: for VM the figures were 22.8, 20.8, 26.4 & 22.0 respectively.Conclusions:1) In the 2nd line HR+ setting AI & Ful 250 both significantly increased PFS & OS in nVM versus VM. Longer PFS appears due to longer duration of control (DoCB) than increasing the number of patients responding (CBR).

2) Median OS for nVM ranged from 24 – 35 months versus 20.8-26.4 months for VM: for the majority of patients the 2nd line ET setting is not ‘immediately life threating’ and ET is therefore an option to consider.

3) These data on site of disease (nVM vs VM) contribute to the selection of which patients should receive endocrine mono- and which endocrine combination therapy (ie plus mTORi or CDK4/6i) in the second line setting.

Citation Format: Robertson JFR, Di Leo A, Johnston S, Chia S, Bliss J, Bradbury I, Campbell C. Meta-analyses of visceral versus non-visceral metastases treated by AI & SERD agents as 2nd line endocrine therapy (ET) for HR+ breast cancer (BC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-13-13.

Abstract P1-06-07: Characterization of chromosomal instability in the TNT trial: A randomized phase III trial of carboplatin compared with docetaxel for patients with metastatic or recurrent locally advanced triple negative or BRCA1/2 breast cancer (CRUK/07/012)

Background

A distinctive trait of triple negative breast cancer (TNBC) is the acquisition of genome wide highly aberrant copy number states, which is more evident in metastatic settings. The level of copy number alterations can be characterized by quantitative estimates of chromosomal instability, such as allelic imbalanced copy number aberrations, telomeric allelic imbalance (NtAI), homologous recombination deficiency (HRD) score, referred here as genomic scars. Several of these scars are reported as being indicative of BRCAness and potential predictive and/or prognostic biomarkers of chemotherapy response, currently mostly demonstrated in neoadjuvant settings in TNBC.

Aims

Using several genomic scar measures, we aim to capture chromosomal instability and test their predictive and prognostic value in metastatic or recurrent locally advanced triple negative or BRCA1/2 mutated breast cancer in the TNT trial.

Methods

Patients recruited to TNT (n=376) had ER-/PR-/Her2- breast cancer or were germline BRCA mutation carriers. Genome-wide copy numbers (CN) were derived from FFPE samples including primary tumours and positive lymph nodes (n=183, docetaxel=93, carboplatin=90; BRCA1 mut=25). Genomic scars were generated using ASCAT (Van loo et al., PNAS 2010) CN profiles. HRD scores were established by Myriad Genetics, Inc. assay (n=272). BRCA1-like classifier was applied as described in Schouten et al., Mol Onc 2015. Shannon diversity index was calculated using ASCAT raw CN profiles. Association of genomic scars with PAM50 subtypes and BRCA1 deficiency status were evaluated using Kruskal-Wallis test; p-values were adjusted for multiple comparisons (Dunn's test). Statistical significance was defined as p&lt;0.05. Association of genomic scars with objective tumour response rate (ORR) and Progression Free Survival (PFS) was assessed using logistic regression and restricted mean survival analysis, respectively.

Results

HRD and NtAI scores were higher in basal like samples compared to non-basal like (median diff. HRD=11.5, p=0.005; NtAI=3, p=0.04). HRD (p=2e-14) and NtAI (p=0.003) scores were also higher in BRCA1 deficient (BRCA1 germline/somatic mutant or BRCA1 methylated) samples compared to non-deficient. Using the BRCA1-like classifier, 42 out of 50 BRCA1 deficient samples and 93 out of 133 BRCA1 non-deficient/undetermined samples were identified as BRCA1-like. The Shannon diversity index, measuring CN heterogeneity, clustered samples into 3 groups. Analysis of ORR showed non-significant trends to preferential response rates with docetaxel in cluster 1 and 3. Membership of cluster 2 predicted higher ORR to carboplatin over docetaxel (interaction p=0.017). PFS indicated a treatment effect in cluster 2, but not in cluster 1 or 3; there was no evidence of interaction between subgroups and treatment (p=0.15).

Conclusions

Our results suggest that the overall heterogeneity of the copy number landscape is a promising area for seeking predictive/prognostic biomarkers in metastatic TNBC, and combined with other modalities of high-dimensional omics data could provide essential treatment response information.

Citation Format: Sipos O, Tovey H, Quist J, Haider S, Nowinski S, Gazinska P, Kernaghan S, Toms C, Timms KM, Lanchbury JS, Linn SC, Pinder SE, Bliss JM, Tutt A, Cheang MC, Grigoriadis A, On behalf of the TNT Trial Management Group and Investigators. Characterization of chromosomal instability in the TNT trial: A randomized phase III trial of carboplatin compared with docetaxel for patients with metastatic or recurrent locally advanced triple negative or BRCA1/2 breast cancer (CRUK/07/012) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-06-07.

Abstract GS3-02: PALLET: A neoadjuvant study to compare the clinical and antiproliferative effects of letrozole with and without palbociclib

Background: CDK4/6 inhibitors, such as palbociclib, are used to treat ER+ metastatic breast cancer in combination with endocrine therapy with trials ongoing in patients with primary disease. No biomarkers exist to identify those who do/do not benefit from added CDK4/6 inhibition. PALLET is an investigator-initiated/led phase II randomized trial collaboration between UK and NSABP investigators evaluating the biological and clinical effects of palbociclib with letrozole combination as neoadjuvant therapy.

Methods: Postmenopausal women with ER+ primary breast cancer and tumors &gt;2.0cm (ultrasound) were randomized to one of 4 treatment groups (3:2:2:2 ratio): Group A: letrozole (2.5mg/d) for 14 weeks; Group B: letrozole for 2 weeks followed by letrozole + palbociclib to 14 weeks; Group C: palbociclib for 2 weeks followed by letrozole + palbociclib to 14 weeks; Group D: letrozole + palbociclib for 14 weeks. Palbociclib was given 125mg/d PO on a 21 days on, 7 days off schedule. Post-14 week treatment was at the discretion of the treating clinician including letrozole until surgery. Core-cut biopsies were taken at baseline, 2 weeks and 14 weeks. Co-primary endpoints for letrozole alone vs palbociclib groups (Group A vs Groups B+C+D) were: (i) change in Ki67 (IHC) between baseline and 14 weeks (log-fold change, Mann-Whitney test); (ii) clinical response (ultrasound) after 14 weeks (4 group, ordinal, Mann-Whitney test). Complete cell-cycle arrest (CCCA) (Ki67≤2.7%) was analyzed using a logistic regression model adjusting for recruitment region. Pre-specified exploratory biomarkers included c-PARP (apoptosis).

Results: 307 patients were recruited between 27 Feb 2015 and 08 Mar 2018; 103 were randomized to letrozole alone and 204 to letrozole + palbociclib. 279 (90.9%) patients were evaluable for 14 week clinical response. Clinical response was not significantly different between letrozole vs letrozole + palbociclib groups [(p=0.20; CR+PR 49.5% (46/93) vs 54.3% (101/186) and PD 5.4% (5/93) vs 3.2% (6/186)] nor was the small proportion of patients with pathological CR (1/87, 1.1% vs 6/180, 3.3%; p=0.43). 190 (61.9%) patients were evaluable for 14 week change in Ki67. The median log-fold change in Ki67 was greater with letrozole + palbociclib vs letrozole alone (-4.1 vs -2.2; p&lt;0.001) corresponding to a geometric mean change of -97.4% vs -88.5%. Similarly, a greater proportion of patients who received letrozole + palbociclib achieved CCCA (90% vs 59%, p&lt;0.001). 146 (47.6%) patients were evaluable for c-PARP and the log-fold change (suppression) was greater with letrozole + palbociclib vs letrozole alone (-0.80 vs -0.42; p=0.003) corresponding to a geometric mean change of -56.8% vs -31.4%. Other biomarkers of response / resistance are being evaluated. A higher proportion of patients had a grade ≥3 toxicity on letrozole + palbociclib than letrozole alone (49.8% vs 17.0%; p&lt;0.001) mainly due to asymptomatic neutropenia.

Conclusion: Adding palbociclib to letrozole markedly enhanced the suppression of malignant cell proliferation as assessed by Ki67 but did not substantially increase the clinical response of primary ER+ breast cancer over a 14-week period. Concurrent reductions in cell death may have reduced the speed of tumor shrinkage.

Citation Format: Dowsett M, Jacobs S, Johnston S, Bliss J, Wheatley D, Holcombe C, Stein R, McIntosh S, Barry P, Dolling D, Snowdon C, Perry S, Batten L, Dodson A, Martins V, Modi A, Cornman C, Puhalla S, Wolmark N, Julian T, Pogue-Geile K, Robidoux A, Provencher L, Boileau JF, Shalaby I, Thirlwell M, Fisher K, Huang Bartlett C, Koehler M, Osborne K, Rimawi M. PALLET: A neoadjuvant study to compare the clinical and antiproliferative effects of letrozole with and without palbociclib [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr GS3-02.

Abstract GS4-05: Dose escalated simultaneous integrated boost radiotherapy for women treated by breast conservation surgery for early breast cancer: 3-year adverse effects in the IMPORT HIGH trial (CRUK/06/003)

Background

IMPORT HIGH is a randomised, multi-centre phase III trial testing dose escalated simultaneous integrated boost (SIB) against sequential boost each delivered by intensity modulated radiotherapy (IMRT) for early stage breast cancer with higher risk of local relapse. The primary endpoint was initially breast induration at 3 years, requiring 840 patients; accrual was extended (target 2568) with the new primary endpoint of local relapse. We report adverse effects (AE) at 3 years.

Methods

Women age ≥18 after breast conservation surgery for pT1-3 pN0-pN3a M0 invasive carcinoma were eligible. Randomisation was 1:1:1 between 40Gy/15F to whole breast (WB) + 16Gy/8F sequential photon boost to tumour bed (40+16Gy), 36Gy/15F to WB, 40Gy to partial breast + 48Gy (48Gy) or + 53Gy (53Gy) in 15F SIB to tumour bed. AEs were assessed annually by clinicians in all patients and in a planned sub-set (840) of patients by photographs at 3 years and by patients at 6 months, 1 and 3 years. AE scores were dichotomised as none/mild vs marked for photographs and none/mild vs moderate/marked for patients and clinicians. Fisher's exact tests compared groups; principal comparison (protocol-specified) between 53Gy and 48Gy (p&lt;0.01 defined as statistical significance).

Results

2617 women consented between 03/2009 and 09/2015 from 39 UK radiotherapy centres. Median follow-up was 49.1 (IQR 36.8-63.2) months. Median age was 49 (IQR 44-56); 9%, 38% & 53% were tumour grade 1, 2 & 3 respectively; 30% were node positive. 66% received chemotherapy and 73% endocrine therapy. 3-year AE data were available for 2017 clinician assessments, 641 photographs and 842 patient assessments. Proportions of patients with marked AEs were low overall. Rates of moderate/marked AEs at 3 years were broadly similar between the randomised groups; with a suggestion of a slightly increased risk for breast induration in 53Gy compared with control (borderline significance).

AE at 3 years 40+16Gy n(%)48Gy n(%)53Gy n(%)ClinicianBreast induration;N656668654None451 (69)483 (72)445 (68)Mild167 (25)141 (21)146 (22)Moderate32 (5)42 (6)56 (9)Marked6 (1)2 (1)7 (1)P-value 0.57010.0102  0.0443Breast shrinkage;N655669654None442 (68)472 (71)448 (69)Mild167 (26)161 (24)166 (25)Moderate40 (6)33 (5)35 (5)Marked6 (1)3 (1)5 (1)P-value 0.25410.5772  0.6373Breast distortion;N656669654None451 (69)464 (69)442 (68)Mild169 (26)170 (25)170 (26)Moderate33 (5)32 (5)38 (6)Marked3 (1)3 (1)4 (1)P-value 0.90310.4862  0.4113PatientChange in breast appearance;N287264285None38 (13)50 (19)58 (20)Mild164 (57)151 (57)142 (50)Moderate57 (20)45 (17)54 (19)Marked28 (10)18 (7)31 (11)P-value 0.14910.9992  0.1243PhotographChange in breast appearance;N218210213None183 (84)185 (88)177 (83)Mild25 (11)23 (11)32 (15)Marked10 (5)2 (1)4 (2)P-value 0.03610.1732  0.6853148Gy v 40+16Gy; 253Gy v 40+16Gy; 353Gy v 48Gy

Conclusions

These results represent the largest and most mature reported AE outcomes of breast SIB within a clinical trial. At 3 years, rates of moderate/marked AEs were similar between SIB IMRT and WB + sequential boost IMRT delivered over 3 and 4.5 weeks respectively.

Citation Format: Coles CE, Griffin CL, Kirby AM, Haviland JS, Titley JC, Benstead K, Brunt AM, Chan C, Ciurlionis L, Din OS, Donovan EM, Eaton DJ, Harnett AN, Hopwood P, Jefford ML, Jenkins PJ, Lee CE, McCormack M, Sherwin L, Syndikus I, Tsang Y, Twyman NI, Ventikaraman R, Wickers S, Wilcox MH, Bliss JM, Yarnold JR. Dose escalated simultaneous integrated boost radiotherapy for women treated by breast conservation surgery for early breast cancer: 3-year adverse effects in the IMPORT HIGH trial (CRUK/06/003) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr GS4-05.

Women's Free-text Comments on their Quality of Life: An Exploratory Analysis from the UK Standardisation of Breast Radiotherapy (START) Trials for Early Breast Cancer

Aims

Exploratory analysis of patients' unsolicited written comments in the first 2 years of the Standardisation of Breast Radiotherapy (START) trial quality of life study highlighted a potential effect of non-treatment-related problems on the ratings and interpretation of patient self-reported questionnaires. At 5 years of follow-up all eligible subjects were invited to write comments to further explore these findings.

Materials and methods

Using inductive qualitative methods informed by the exploratory analysis, comments were allocated to relevant themes. Key patient-reported outcome measures (PROMs), clinical and demographic factors were collated for patients who did and did not comment at 5 years and comparisons between the groups explored.

Results

Of 2208 women completing baseline PROMs, 482 proffered comments from 0 to 24 months, forming nine distinct themes, including chronic conditions, life events and psychosocial concerns. At 5 years, 1041/1727 (60.3%) women contributed comments, of whom 500 randomly selected participants formed the sample for analysis. Findings revealed comorbidity, impaired physical functioning and psychosocial problems as key themes, with prevalent adverse effects from local and systemic treatments. Eight new themes emerged at 5 years, including ageing, concerns about future cancer and positive aspects of care. Women commenting were better educated, slightly older and more likely to have had chemotherapy compared with non-commenters. They had significantly worse PROM scores for global health and key quality of life domains relevant to the difficulties they revealed.

Conclusions

Difficult personal circumstances and other health concerns affected many women's PROM ratings at 5 years of follow-up, in addition to ongoing cancer treatment effects. Greater attention to multiple sources of distress and adversity could facilitate personalised care and aid interpretation of PROMs.

Can Interrogation of Tumour Characteristics Lead us to Safely Omit Adjuvant Radiotherapy in Patients with Early Breast Cancer?

Adjuvant radiotherapy after breast-conserving surgery has been an important component of the standard of care for early breast cancer. Improvements in breast cancer care have resulted in a substantial reduction in local relapse rates over recent decades. Although the proportional benefits of adjuvant radiotherapy are similar for different prognostic risk groups of patients, the absolute benefits depend on the risk of relapse and therefore vary considerably between prognostic groups. Radiotherapy is not without risk and for some patients at very low risk of relapse the risks of radiotherapy may outweigh the benefit, leading to potential overtreatment. Randomised controlled trial (RCT) evidence shows that omission of radiotherapy in low risk early breast cancer does not reduce overall survival or increase breast cancer mortality and local recurrences are salvageable. Despite this there has not been a change in practice regarding omission of radiotherapy. The reasons for this may include challenges in patient selection. Recent advances in immunohistochemistry and genomic profiling may improve risk stratification and the development of biomarkers to directed therapies. Several RCTs have quantified the benefit of radiotherapy in reducing local relapse. Where a treatment benefit is known but is considered to be so small not to be clinically relevant then alternatives to RCTs may be considered to answer the question of need. This is because we can assess risk against a fixed 'absolute' boundary rather than needing a randomised comparator. The prospective cohort study is an alternative to the RCT design to answer the question of need for radiotherapy. The feasibility of recruitment into biomarker-directed de-escalation studies will become apparent as more studies open. The challenge is to determine if we are able to accurately risk stratify patients and avoid unnecessary toxicity, thereby tailoring the need for adjuvant breast radiotherapy on an individual patient basis.

Abstract OT1-06-03: The plasmaMATCH trial: A multiple parallel cohort, open-label, multi-centre phase II clinical trial of ctDNA screening to direct targeted therapies in patients with advanced breast cancer (CRUK/15/010)

Introduction

Circulating tumour DNA (ctDNA) is found in the plasma of over 90% of patients with advanced breast cancer (BC). Screening for the presence of mutations in ctDNA provides a current assessment of the genetic profile of the patient's recurrent BC. The plasmaMATCH trial is designed to assess the potential of ctDNA screening to direct targeted therapies in patients with advanced breast cancer.

Methods

plasmaMATCH is a multi-centre phase IIa umbrella trial platform of ctDNA screening and a therapeutic trial. The study will screen 1000 women with advanced breast cancer, who have received prior systemic treatment in the advanced setting, with digital PCR ctDNA assays for hotspot mutations in ESR1, HER2, AKT1, and PIK3CA, with HER2 copy number assessment, in a central laboratory. The study will recruit from up to 50 sites in the UK. Patients with mutations identified will enter the matching treatment cohort, ESR1 – extended dose fulvestrant 500mg every two weeks, HER2 – neratinib +/- fulvestrant, AKT1 – AZD5363 +/- fulvestrant.

Mutation prevalence is presented with corresponding exact 95% confidence intervals (CIs) both overall and excluding 14 patients who were known to have mutations from a prior screening program. Patients with more than one mutation are included once in each relevant row.

Results

We report the results of prospective ctDNA mutation testing in the first 92 patients. plasmaMATCH opened to recruitment on 15/12/2016. As of 08/06/2017, 120 patients have been registered for ctDNA screening from 7 UK centres, of which 92 have ctDNA screening results available:

plasmaMATCH ctDNA screening resultsMutationPrevalence (95% CI)Prevalence excluding 14 patients with known mutations (95% CI)ESR134/92: 37% (27%-48%)26/78: 33% (23%-45%)HER25/90: 6% (2%-12%)2/76: 3% (0%-9%)AKT17/92: 8% (3%-15%)4/78: 5% (1%-13%)PIK3CA*22/92: 24% (16%-34%)21/78: 27% (18%-38%)*No corresponding plasmaMATCH treatment cohort

14 patients had more than one mutation detected (10 ESR1+PIK3CA, 3 ESR1+AKT1, 1 ESR1+ +HER2+AKT1). ctDNA results were reported in a median of 8 working days.

Of the 40 patients with one or more actionable mutation, 15 have entered a cohort, 16 are being screened for entry into a cohort, 5 are currently receiving further systemic treatment prior to cohort entry and 4 will not enter a cohort. One additional patient has entered a treatment cohort on the basis of a mutation detected in an alternative tumour sequencing initiative.

Conclusions

plasmaMATCH ctDNA demonstrates the feasibility and accuracy of ctDNA testing as a screening tool for patients with advanced BC, with a high rate of subsequent recruitment into matching therapeutic trials.

Citation Format: Turner N, Bye H, Kernaghan S, Proszek P, Fribbens C, Moretti L, Morden J, Snowdon C, Macpherson I, Wardley A, Roylance R, Baird R, Bliss J, Ring A. The plasmaMATCH trial: A multiple parallel cohort, open-label, multi-centre phase II clinical trial of ctDNA screening to direct targeted therapies in patients with advanced breast cancer (CRUK/15/010) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT1-06-03.

Abstract GS3-03: A phase III multicentre double blind randomised trial of celecoxib versus placebo in primary breast cancer patients (REACT – Randomised EuropeAn celecoxib trial)

Background

Inhibition of COX-2 has been shown to attenuate the metastatic process in pre-clinical models of human breast cancer (BC). The primary aim of this study was to assess the effect of 2 years adjuvant therapy with the COX-2 inhibitor celecoxib compared with placebo in HER2-ve primary BC patients.

Patients & Methods

Patients were randomised in a 2:1 ratio to receive celecoxib 400mg once daily or placebo for 2 years. Patients had to have completely resected BC with prior local and systemic adjuvant treatment according to local practice. Concurrent radiotherapy was permitted and hormone receptor +ve patients received endocrine therapy according to local practice. Patients with HER2+ or node negative, T1 and grade 1 disease were excluded. Median age of patients was 55 years (IQR: 49-63). 50% of patients had tumours &gt;2cm; 42% were grade 3; 48% had node +ve disease. According to local assessment 73% were ER/PgR +ve. Primary endpoint was Disease Free Survival (DFS); defined as time from randomisation to date of first event, with events contributing to analysis defined as recurrence (distant/local), new primary BC (ipsilateral/contralateral) and death. Secondary endpoints included Overall Survival (OS), toxicity, cardiovascular mortality and incidence of second primaries. Subgroup analysis by hormone receptor status was pre-planned. Survival endpoints are analysed using Cox-proportional hazards and log-rank tests; restricted mean survival is used where proportional hazards do not hold.

Results

Between January 2007 and November 2012, 2639 patients were randomised (1763 celecoxib; 876 placebo) from 181 centres across the UK and Germany. At 13th April 2017, median follow up was 60 months (IQR: 48-72) with 428 DFS events reported. Unadjusted survival analysis results are presented below, with hazard ratio&lt;1 favouring celecoxib:

 5 year survival estimate (95% CI)Hazard ratio (95% CI)p-valueDFS (all patients)   Celecoxib83% (81, 85)1.02 (0.83 – 1.24)0.88Placebo83% (80, 86)1-    DFS within ER+   Celecoxib87% (85, 89)0.89 (0.69 – 1.16)0.40Placebo86% (83, 89)1-    DFS within ER-   Celecoxib72% (68, 76)1.17 (0.85 – 1.61)0.33Placebo75% (69, 80)1-    OS (all patients)   Celecoxib90% (88, 91)0.97 (0.75 – 1.25)0.81Placebo90% (88, 92)1-

The interaction between ER status and treatment was not significant; p=0.36.

In the celecoxib and placebo groups there were 17 and 8 deaths respectively in patients who had not relapsed. These were due to cardiac (n=3; 2) and other (n=14; 6) in the celecoxib and placebo groups respectively; none were GI related. In total 304 serious adverse events were observed in 265 patients (186/1763 celecoxib; 79/876 placebo). In the celecoxib and placebo groups respectively these were related to cardiac (n=12; 7), GI (n=9; 2) and other (n=193; 81). Work is ongoing to determine whether a subset of ER+ patients whose primary tumours show the characteristics of a COX-2 signature receive greater benefit from celecoxib.

Conclusions

There is no benefit of celecoxib in the ITT population. Further exploratory studies focussing on the ER+ subpopulation are ongoing. Celecoxib treatment is not associated with significant toxicity when compared to placebo in this population of BC patients.

Citation Format: Coombes RC, Tovey H, Kilburn L, Mansi J, Palmieri C, Bartlett J, Hicks J, Makris A, Evans A, Loibl S, Denkert C, Murray E, Grieve R, Coleman R, Schmidt M, Klare P, Rezai M, Rautenberg B, Klutinus N, Rhein U, Mousa K, Ricardo-Vitorino S, von Minckwitz G, Bliss J. A phase III multicentre double blind randomised trial of celecoxib versus placebo in primary breast cancer patients (REACT – Randomised EuropeAn celecoxib trial) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr GS3-03.

Abstract PD5-05: Genomic instability and poor antiproliferative response to aromatase inhibitor treatment: A POETIC study

Background:

More than 20% of early-stage patients with estrogen positive (ER+) disease relapse. Higher levels of the proliferation marker Ki67, and lack of reduction of Ki67 in response to AI indicate poorer prognosis. Somatic mutations have been the focus of research in treatment resistance. However, recurrent somatic copy number alterations (SCNAs) are more common and affect more genes in primary breast cancer (BC) than somatic mutations. Previous studies have suggested an increased risk of recurrence for patients with high genomic instability and for patients with loss of heterozygosity (LOH) at the TP53 locus, but it is unknown if these SCNA events impact response to AI treatment. In addition, LOH and mutations at the TP53 locus had a higher risk of recurrence than LOH or mutations at TP53 alone. We hypothesised that genomic instability and SCNAs at particular loci would be increased in early BC patients with high baseline Ki67, and particularly in patients with high Ki67 despite pre-operative AI therapy.

Methods:

In a substudy of POETIC (UK-wide, phase III, randomised trial with 4483 women testing perioperative AI in postmenopausal women with early BC), SNParray technology was used to determine SCNAs in baseline and surgical tumour core-cuts and blood from 76 patients (59 AI-treated, 17 controls). Proliferation rate was estimated as percentage (%) of cancer cells staining for Ki67 by IHC. Poor AI responders (PR, &lt;60% reduction in Ki67 between baseline and surgery, n=31) and good AI responders (GR, &gt; 75% reduction in Ki67, n=28) were selected from POETIC samples. Mutation data from exome sequencing was available for tumours from 75 of the patients.

Results:

The fraction of the genome with SCNAs correlated with Ki67 expression in both baseline and surgical samples (baseline Spearman rho=0.5, p &lt; 10-5; surgical Spearman rho=0.44, p &lt; 10-3). In paired baseline vs surgical samples, 24% of samples showed discordance in SCNAs that covered &gt; 10% of the genome. The samples showing the highest discordance were from PRs.

The fraction of the genome with LOH was greater in PR (median PR 20%, GR 10%, p = .065), and the best SCNA to predict the fraction of the genome altered in a sample were segments with LOH at Chr17p13.3 (adjusted p &lt; .001, logistic regression). There was a higher percentage of patients with LOH at Chr17p13.3 that contains the TP53 gene in the PR compared to GR group (PR 71%, GR 39%, p = .029), and integration of previously generated mutation data with SCNA showed that 9 out of 31 PRs have mutations and LOH at the TP53 locus compared to 3 out of 28 GRs (p = 0.16).

Conclusions:

There is discordance between the observed SCNAs in paired samples with high genomic instability and multiple biopsies may be needed to confidently assess all SCNAs. However, LOH at Chr17p13.3 is a biomarker for genomic instability and frequency of LOH is significantly greater in patients that show a poor response to AI treatment. Finally, high genomic instability is associated with high proliferation rates at baseline and surgery after 2 weeks of AI treatment suggesting de novo resistance in tumours with high instability that may lead to a higher rate of recurrence seen in these patients.

Citation Format: Schuster EF, Gellert P, Segal CV, López-Knowles E, Buus R, Morden J, Robertson J, Bliss J, Smith I, Dowsett M, POETIC Trial Management Group and Trialists P. Genomic instability and poor antiproliferative response to aromatase inhibitor treatment: A POETIC study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD5-05.

Abstract P3-13-01: Withdrawn

This abstract was withdrawn by the authors.

Abstract P2-02-01: Withdrawn

This abstract was withdrawn by the authors.

Evaluation of applying IHC4 as a prognostic model in the translational study of Intergroup Exemestane Study (IES): PathIES

BACKGROUND

Intergroup Exemestane Study (IES) was a randomised study that showed a survival benefit of switching adjuvant endocrine therapy after 2-3 years from tamoxifen to exemestane. This PathIES aimed to assess the role of immunohistochemical (IHC)4 score in determining the relative sensitivity to either tamoxifen or sequential treatment with tamoxifen and exemestane.

PATIENTS AND METHODS

Primary tumour samples were available for 1274 patients (27% of IES population). Only patients for whom the IHC4 score could be calculated (based on oestrogen receptor, progesterone receptor, HER2 and Ki67) were included in this analysis (N = 430 patients). The clinical score (C) was based on age, grade, tumour size and nodal status. The association of clinicopathological parameters, IHC4(+C) scores and treatment effect with time to distant recurrence-free survival (TTDR) was assessed in univariable and multivariable Cox regression analyses. A modified clinical score (PathIEscore) (N = 350) was also estimated.

RESULTS

Our results confirm the prognostic importance of the original IHC4, alone and in conjunction with clinical scores, but no significant difference with treatment effects was observed. The combined IHC4 + Clinical PathIES score was prognostic for TTDR (P < 0.001) with a hazard ratio (HR) of 5.54 (95% CI 1.29-23.70) for a change from 1st quartile (Q1) to Q1-Q3 and HR of 15.54 (95% CI 3.70-65.24) for a change from Q1 to Q4.

CONCLUSION

In the PathIES population, the IHC4 score is useful in predicting long-term relapse in patients who remain disease-free after 2-3 years. This is a first trial to suggest the extending use of IHC4+C score for prognostic indication for patients who have switched endocrine therapies at 2-3 years and who remain disease-free after 2-3 years.

Abstract P2-10-02: The impact of intrinsic subtypes and molecular features on aromatase inhibitor induced reduction of proliferation marker of Ki67 in primary ER+ breast cancer: A POETIC study (CRUK/07/015)

Background

Neoadjuvant endocrine therapy (NAE) is often a good option for postmenopausal (PM) women with estrogen receptor positive (ER+) breast cancers(BC). Fall in Ki67 is widely accepted as valid for predicting favorable tumor response to NAE and improved outcome. We report our planned correlative study to investigate if intrinsic subtype impacts on Ki67 changes (ΔKi67) as measured by immunohistochemistry. We also explored the correlation of several ER+ BC relevant molecular features at baseline(B) with ΔKi67.

Patients and methods

POETIC is a phase III, randomized 2:1 study for 4486 PM patients with ER+ BC to determine whether peri-operative aromatase inhibitor (AI) followed by standard adjuvant therapy improves outcome compared with standard adjuvant therapy alone. The proliferation rate was estimated as percentage (%) of cancer cells staining for Ki67. Primary biological endpoint was defined as two-week (2wk) change in Ki67 (2wkΔKi67): ln[(2wk Ki67+0.1)/(B Ki67+0.1)]. Secondary endpoint: “responders”, was % change of Ki67 defined as (2wk Ki67 – B Ki67) *100/B Ki67. “Responder” was defined as follows: reduction &lt;50% as poor (PR), 50-75% moderate and &gt;75% as good responder (GR).

Human whole genome expression(GE) Illumina BeadChips were performed. Data was obtained from 137 paired samples from the treatment group(T) and 49 pairs from the control(C) group with GE data passing quality check and baseline Ki67≥5% to minimise the impact of extreme values based on proportional ΔKi67. Intrinsic subtype and risk of recurrence(ROR) groups were calculated using PAM50. GE scores from Oncotype Dx, MammaPrint, p53 mutation/wildtype(Troester 2006), ER+ early response (ERE)(Hatzis 2011), estrogen-regulated genes subtypes (Oh 2006) and markers for 23 different immune cell types(Bindea 2013) were calculated. Associations of GE scores to endpoints of response were determined by Spearman correlation and chi-square tests. Bonferroni correction was used to control error rate with p&lt;0.0005 deemed significant.

Results

At B of the 137 paired T, 64% were Luminal A (LumA), 22% Luminal B (LumB), 9% as HER-2 enriched (HER2-E), 2% as Basal-like (BLBC) and 3% as Normal-like. Subtypes at B were associated with response, with LumA showing the biggest reduction of Ki67 (p=0.0001) and GR. All GE, except ERE, correlated significantly with 2wkΔKi67 and response: higher risk groups associated with lowest reduction rate. None of immune cell types correlated with 2wkΔKi67, except that tumors enriched with T-helper 1 cell type were associated with PR (p &lt; 0.000001).

Comparing subtypes between time-points, 85% of LumB and 42% of HER2-E were assigned instead as LumA at 2wk regardless of response. Of the 15 ROR defined high-risk group, only 33% were assigned instead as low-risk at 2wk.

Conclusion

Both LumA and LumB are endocrine sensitive. A fall of Ki67 was observed in majority of cases. Most tumors estimated as high-risk by molecular profiling showed less response and most remained moderate or high risk of recurrence on endocrine therapy. Whether molecular profiling at 2wk after starting AI predicts for long-term outcome in PM women with ER+ better than at diagnosis will need to be determined.

Citation Format: Cheang MCU, Morden J, Gao Q, Parker J, López-Knowles E, Detre S, Hills M, Zabaglo L, Tomiczek M, Mallon E, Robertson J, Smith I, Bliss J, Dowsett M, On Behalf of the POETIC Trialists. The impact of intrinsic subtypes and molecular features on aromatase inhibitor induced reduction of proliferation marker of Ki67 in primary ER+ breast cancer: A POETIC study (CRUK/07/015) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-10-02.

Abstract P1-02-01: Circulating tumor DNA analysis to predict relapse and overall survival in early breast cancer – Longer follow-up of a proof-of-principle study

Background

In a previous proof-of-principle study we demonstrated that detection of circulating tumour DNA (ctDNA) in the adjuvant setting, after completion of surgery and chemotherapy for early stage breast cancer, was associated with a high risk of early relapse. Here we present longer follow-up of the same series, to define the predictive power of ctDNA analysis for disease free survival, and assess the potential to predict overall survival.

Methods

We recruited a cohort of 55 women presenting with early stage, primary breast cancer, who were all scheduled to receive neo-adjuvant chemotherapy. The primary tumour was sequenced to identify somatic mutations, identifying at least one mutation in 43 patients. Mutations were tracked with digital PCR to identify ctDNA, in plasma samples taken either at a single post-surgical time point (2-6 weeks post-surgery) or with serial plasma samples taken every 6 months in the adjuvant setting.

Results

At a median 31.7 months follow-up, 42% (18/43) patients had relapsed. Detection of ctDNA at the single post-surgical time point was associated with poor disease free survival, HR=13.6 95%CI (4.5, 41.2) p&lt;0.001, and overall survival HR=84.7 95%CI (9.8, 730.4) p&lt;0.001. All patients with ctDNA detected in a single post-surgical time point relapsed and died in the follow-up period (7/7, 100% specificity), although the single post-surgery time point had modest 39% (7/18) sensitivity for relapse. Detection of ctDNA at any point in serial sampling was associated with poor disease free survival HR=25.7 95%CI (8.3, 79.8) p&lt;0.001 and overall survival HR=47.1 95%CI (6.1, 366.1) p&lt;0.001. All patients with ctDNA detected in a serial mutation tracking relapsed in the follow-up period (14/14, 100% specificity), with 78% (14/18) sensitivity for relapse. Sensitivity was limited by 3 cases of brain only relapse and one case of solitary ovarian relapse. Detection of ctDNA in serial sampling had a median lead-time of 8.1 months over clinical relapse.

Conclusion

Detection of ctDNA in the adjuvant setting has a high predictive power for future relapse and death from breast cancer. Therapeutic trials are required to determine whether mutation tracking identifies relapse sufficiently early to allow for further adjuvant therapy.

Citation Format: Turner NC, Garcia-Murillas I, Chopra N, Beaney M, Kilburn L, Cutts R, Osin P, Nerurkar A, Schiavon G, Hrebien S, Bliss J, Dowsett M, Smith I. Circulating tumor DNA analysis to predict relapse and overall survival in early breast cancer – Longer follow-up of a proof-of-principle study [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-02-01.

Abstract P2-09-02: True effect of aromatase inhibitor (AI) treatment on global gene expression (expr) changes in postmenopausal ER+ breast cancer (BC) patients: A POETIC study (CRUK/07/015)

BACKGROUND Gene expression (expr) analyses are increasingly used for characterising the pharmacodynamic response of primary BC. This includes assessing ER+ BC's dependence on estrogen (E) by measuring gene expr changes after AI-treatment. However, differences in tissue sampling and other preanalytic procedures between samples taken at diagnosis (D) and surgery (S), may lead to systematic artifactual changes that are falsely ascribed to the intervention. To identify genes whose expr is truly affected by AI, we measured global gene expr changes from paired core-cut biopsies at D and S from patients in the POETIC presurgical window trial.

METHODS In POETIC, 4486 postmenopausal women with primary ER+ BC were randomised 2:1 to receive perioperative AI (2 weeks pre + 2 weeks post surgery, termed Tr) or no perioperative treatment (termed Con), allowing gene expr changes to be compared between Tr and Con. RNA was extracted from paired RNA-later stored core-cuts of 56 Con and 157 Tr patients and arrayed on Illumina whole genome expr BeadChips. Raw data was extracted, transformed, normalised and batch-corrected. Probes not detected (p&gt;0.01) in &gt;=25% of samples were discarded. Impact of AI on genes was evaluated based on difference of the expr mean changes (log2(S/D)) of the Tr and Con samples.

RESULTS In the Con group, expr of 73 genes significantly changed (FDR&lt;5%); 70 of these changed by a similar magnitude in the Tr group, indicating their change was independent of AI therapy but would have been artifactually discovered as changed by AI in the absence on Con. The 8 genes most up-regulated in Tr were all among the 20 genes most up-regulated in Con: many were early-response or stress-associated genes. Three of the 8 most down-regulated in AI were the most down-regulated in Con: all were haemoglobin-related. Expr of some genes was changed in Con (eg MYC increase) but was unaffected in Tr. Such artifactual gene changes in Con tumors conceal true AI-induced changes that would not be detected in the absence of comparison with Con.

615 genes were down-regulated and 472 up-regulated in Tr but not Con. The majority of down-regulated genes were cell cycle or proliferation-associated or E-regulated, including ESR1, PDZK1, GREB1, HSPB1. Functional mapping showed changes in the regulation of cyclins and cyclin dependent kinases impacting on G1/S and G2/M. Of note, up-regulated genes included CDK6 (target for CDK4/6 inhibitors) and CCND2, involved in G1/S checkpoint regulation; SNAI2, TGFB3, TGFBR2, associated with tumour invasion and metastasis; and other genes involved in aryl hydrocarbon receptor, Glioblastoma Multiforme, HIPPO and p53 signalling.

CONCLUSION Expr of certain genes is altered by processes involved in presurgical window studies. In the absence of a Con group, these may be wrongly ascribed to an experimental intervention or wrongly considered as unaffected by the intervention (eg MYC in this study).

Down-regulation of E-responsive and proliferation genes was an expected response to AI but increased expr of genes such as SNAI2, CCND2 and CDK6 indicates immediate tumour re-wiring and provides mechanistic support for benefit from combination therapy with a CDK4/6 inhibitor.

Citation Format: Gao Q, López-Knowles E, Cheang MCU, Morden J, Martin L-A, Sidhu K, Evans D, Martins V, Dodson A, Skene A, Holcombe C, Mallon E, Abigail E, Bliss J, Robertson J, Smith I, Dowsett M. True effect of aromatase inhibitor (AI) treatment on global gene expression (expr) changes in postmenopausal ER+ breast cancer (BC) patients: A POETIC study (CRUK/07/015) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-09-02.

Reversal of the Cry-Wolf Effect: An Investigation of Two Methods to Increase Alarm Response Rates

In complex task environments, false alarms have been associated with less frequent and slower alarm responses. This research attempted to improve alarm responses using a hearsay method, in which participants were told that false alarms would be less frequent than they actually were, and an urgency method, in which the urgency of alarms was increased. Response frequency, speed, and accuracy of three groups of 20 students (Urgency, Hearsay, and Control) were compared across groups and sessions using analyses of variance and t tests. Both methods were successful; hearsay participants increased their response rates across sessions, and urgency participants decreased their response times. The results are discussed with regard to design of alarm systems and theory of human performance.

Do Patient-reported Outcome Measures Agree with Clinical and Photographic Assessments of Normal Tissue Effects after Breast Radiotherapy? The Experience of the Standardisation of Breast Radiotherapy (START) Trials in Early Breast Cancer

AIMS

In radiotherapy trials, normal tissue effects (NTE) are important end points and it is pertinent to ask whether patient-reported outcome measures (PROMs) could replace clinical and/or photographic assessments. Data from the Standardisation of Breast Radiotherapy (START) trials are examined.

MATERIALS AND METHODS

NTEs in the treated breast were recorded by (i) annual clinical assessments, (ii) photographs at 2 and 5 years, (iii) PROMs at 6 months, 1, 2 and 5 years after radiotherapy. Hazard ratios for the radiotherapy schedules were compared. Measures of agreement of assessments at 2 and 5 years tested concordance.

RESULTS

PROMs were available at 2 and/or 5 years for 1939 women, of whom 1870 had clinical and 1444 had photographic assessments. All methods were sensitive to the dose difference between schedules. Patients reported a higher prevalence for all NTE end points than clinicians or photographs (P < 0.001 for most NTEs). Concordance was generally poor; weighted kappa at 2 years ranged from 0.05 (telangiectasia) to 0.21 (shrinkage and oedema). The percentage agreement was lowest between PROMs and photographic assessments of change in breast appearance (38%).

CONCLUSIONS

All three methods produced similar conclusions for the comparison of trial schedules, despite low concordance between the methods on an individual patient basis. Careful consideration should be given to the different contributions of the measures of NTE in future radiotherapy trials.

Epirubicin dose and sequential hormonal therapy-Mature results of the HMFEC randomised phase III trial in premenopausal patients with node positive early breast cancer

BACKGROUND

The hormonal manipulation 5-Fluoro-uracil Epirubicin Cyclophosphamide (HMFEC) trial was developed at a time of uncertainty around the dose intensity of chemotherapy given to premenopausal patients with node positive breast cancer and to the benefits of tailored endocrine therapy in such patients.

PATIENTS AND METHODS

HMFEC was a multi-centre, phase III, open label, randomised controlled trial with a 2 × 2 factorial design. Eligible patients were premenopausal with node positive early breast cancer; significant cardiac disease or uncontrolled hypertension was exclusion criterion. Patients were allocated to receive either eight cycles of FE50C or FE75C (given 3 weekly) with or without hormone manipulation (HM; tamoxifen or luteinising hormone releasing hormone (LHRH) agonists according to residual hormone levels at the end of chemotherapy) irrespective of ER status. The primary end-point was disease free survival (DFS). Principal analyses were by intention to treat (ITT); however, to reflect contemporary practice, subgroup analyses according to ER status were also conducted. The mature follow-up now available from this modest sized trial enables presentation of definitive results.

RESULTS

Between 1992 and 2000 a total of 785 patients were randomised into the HMFEC trial (203 FE50C-HM, 191 FE50C+HM, 198 FE75C-HM, 193 FE75C+HM). At a median follow-up of 7.4 years, 245 DFS events have been reported (92 ER-, 153 ER+/unknown). The effects on DFS were not statistically significantly different according to epirubicin dose (hazard ratio [HR] = 0.82, 95% confidence interval [CI] 0.63-1.06; p = 0.13 FE75C versus FE50C); however, FE75C appeared to induce more alopecia and neutropenia. No statistically significant evidence was observed to support an improvement in DFS in patients allocated HM either overall (HR = 0.88, 95% CI 0.68-1.13; p = 0.32) or in patients with ER+/unknown disease (HR = 0.85, 95% CI 0.62-1.17; p = 0.32) although effect sizes are consistent with worthwhile clinical effects. Overall, there was no evidence of a difference in survival between any of the four treatment groups of the trial.

CONCLUSION

Higher doses of epirubicin cause more adverse events in the absence of clear improvement in overall survival. Endocrine therapy with either tamoxifen or goserelin provided no significant added benefit to cytotoxic chemotherapy in this group of patients.

TRIAL REGISTRATION NUMBER

ISRCTN98335268.

Bone marrow micrometastases in early breast cancer-30-year outcome

BACKGROUND

Micrometastases in bone marrow of women with early breast cancer were first identified immunocytochemically in the 1980s. We report on the original cohort of women with a median follow-up of 30 years.

PATIENTS AND METHODS

In total, 350 women with primary breast cancer had eight bone marrow aspirates examined with antibody to epithelial membrane antigen. Data on long-term mortality were obtained via record linkage to death certification.

RESULTS

At a 30-year median follow-up, 79 out of 89 (89%) patients with micrometastases have died compared with 202 out of 261 (77%) without (hazard ratio=1.46 (95% CI 1.12-1.90), P=0.0043). Most marked effect of micrometastases on overall survival (OS) was seen in patients aged ⩽ 50 at surgery (N=97, P=0.012), and on all patients within 10 years of diagnosis. In multivariable analyses, the presence of micrometastases was no longer a statistically significant prognostic factor.

CONCLUSIONS

Bone marrow micrometastases are predictive for OS, particularly in the first decade and in younger patients.