Abstract P4-08-02: Importance of adverse events during endocrine treatment for the prediction of late distant recurrences

Background: During endocrine treatment of breast cancer, the occurrence of symptoms related to oestrogen depletion are important predictor of treatment efficacy. We have previously shown that appearance of vasomotor and joint related symptoms are a useful biomarker for a greater response to endocrine treatment (Cuzick et al., Lancet, 2008). Furthermore a prediction model including clinicopathological parameters (CTS5) has shown to be a good prognostic tool for the prediction of late distant recurrences (DR) (Dowsett et al., JCO, 2018). Here, we assessed whether the occurrence of endocrine related adverse events were predictive of late DR in the ATAC trial.

Methods: The ATAC trial (N=4735) of postmenopausal women with estrogen receptor positive breast cancer treated with 5 years' tamoxifen or anastrozole was used for this analysis. Women who reported symptoms (hot flashes, joint symptoms, gynaecological symptoms) at any time during the trial were compared to those not reporting these symptoms for late DR. Time to late DR, defined beginning at 5 years after randomization, was the primary endpoint. Hazard ratios (HR) and corresponding 95% CIs were estimated by Cox proportional hazards regression models.

Results: 2937 women (62%) who were recurrence free after 5 years, reported either hot flashes, joint symptoms, or gynaecological symptoms during the active treatment period. Women who reported joint symptoms (adjusted for CTS5: HR=0.74 (0.59-0.94)), or gynaecological symptoms (adjusted for CTS5: HR=0.68 (0.47-0.97)) had significantly fewer late DR compared to those not reporting these events during the active 5 years' treatment period. Those who reported any symptom during the treatment period had an overall 34% lower risk of a late DR (univariate: HR=0.66 (0.53-0.83), P<0.001; adjusted for CTS5: HR=0.75 (0.60-0.93), P=0.009). The 5-10 year DR risk for women who reported any symptoms was 7.4% (6.4-8.5) compared to 11.0% (9.3-12.8) for those without symptoms. Women who reported any symptoms and who were randomized to either anastrozole (HR=0.67 (0.48-0.92)) or tamoxifen (HR=0.65 (0.48-0.88)) had significantly fewer late DR compared to those not reporting these symptoms. Women with symptoms on tamoxifen did have better 10-year DR risk compared to those without symptoms on anastrozole (8.1% (6.7-9.8) vs. 9.8% (7.7-12.4)).

Conclusions: This retrospective analysis of the ATAC trial showed that occurrences of endocrine related symptoms during the treatment period are associated with the risk of developing a late DR, irrespective of treatment allocation. Larger effects were found for joint or gynaecological symptoms and remained significant after adjustment for clinical parameters. These findings might help clinicians and patients in their decision making process about extended endocrine therapy.

Citation Format: Sestak I, Dowsett M, Cuzick J. Importance of adverse events during endocrine treatment for the prediction of late distant recurrences [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 P4-08-02.

Abstract P5-18-08: Defining molecular signatures to personalise management of patients with early breast cancer

Background

A review of breast screening highlighted the need to reduce overdiagnosis. Ductal Carcinoma In-Situ (DCIS) contributes significantly to this overdiagnosis. Epithelial cells in DCIS are as genetically advanced as those in invasive disease, focusing attention on the tumour microenvironment (ME). A key components of the ME in DCIS is the myoepithelial cell(MEC). These cells lie at the interface of the epithelial and stromal compartments, regulating cell function. We previously have identified changes in the MEC that contribute to tumour progression. Here we investigate the functional and clinical significance of a novel change in MEC phenotype: loss of Galectin-7 (Gal-7) expression. Gal-7 is proposed to play a role in apoptosis. We hypothesise that changes in MEC phenotype in DCIS alter the ME towards a pro-invasive phenotype, and hypothesise that loss of Gal-7 modifies the ME, destabilizes the MEC interface and ultimately may lead to loss of the MEC population through apoptosis.

Methods

Gal-7 expression and function was investigated in clinical samples and in-vitro model systems, respectively.

Gal-7 expression was assessed in a series of pure DCIS samples (low risk model) and DCIS with co-existant invasion (high risk model). Tissue sections were stained for Gal-7 and MEC expression scored on a duct-by-duct basis as positive, heterogeneous or negative.

An in-vitro model of normal primary myoepithelial cells isolated from reduction mammoplasty was used to investigate the functional impact of loss of Gal-7. These cells have high endogenous levels of Gal-7. Gal-7 was knocked down using siRNA and apoptosis assessed using cleaved caspase-3. The effect of Gal-7 on MEC layer integrity was assessed using immunofluorescence and adhesion assays.

The global impact of loss of Gal-7 was investigated using RNA sequencing.

Results

In the tissue analysis 1926 DCIS ducts were scored for MEC expression of Gal-7. Significantly more ducts showed loss of Gal-7 in DCIS with co-existant invasion, with pure DCIS showing 388 ducts positive and DCIS with invasion 144 DCIS ducts positive (p=0.0014). Pure DCIS and DCIS with invasion had 99 and 646 negative DCIS ducts respectively (p=0.0002).

In model systems of primary MEC, knockdown of Gal-7 resulted in increased expression of cleaved caspase-3, suggesting lower levels of Gal-7 increases apoptosis. In functional assays silencing Gal-7 reduces adhesion to both fibronectin and laminin extracellular matrices (p-value 0.005 and 0.001 respectively)

RNA sequencing indicates silencing Gal-7 increases LOX expression - a key regulator of the collagen matrix of the microenvironment.

Conclusion

Normal MEC strongly express Gal-7. Expression is lost in DCIS, with significantly more frequent loss in DCIS with co-existant invasion, suggesting that loss is associated with a more advanced phenotype. Functional assays indicate that loss of MEC Gal-7 enhances MEC apoptosis, which may be one mechanism by which this interface is lost during progression. Gal-7 negative MEC also show impaired adhesion to matrix proteins and lead to up-regulation of LOX, an enzyme key in promoting tumourigenesis. The incorporation of Gal-7 expression into a risk stratification algorithm has functional evidence and is currently being investigated.

Citation Format: Allen N, Allen M, Ahmed K, Gomm J, Nelan R, Nagano A, Chelala C, Gadaleta E, Thorat M, Cuzick J, Jones LJ. Defining molecular signatures to personalise management of patients with early breast cancer [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 P5-18-08.

Abstract P2-07-02: A newly derived combined clinical treatment score and immunohistochemical-4 prognostic tool

AIM

To determine whether a modified Clinical Treatment Score (CTS) based on continuous tumor size and 5 lymph node categories provided more prognostic information in an independent test set than the original CTS with and without the Immunohistochemical-4 (IHC4) algorithm for prediction of residual distant recurrence risk over 10-years.

BACKGROUND

Risk of recurrence information in patients with estrogen receptor-positive (ER+), early breast cancer informs decision-making on chemotherapy use. The CTS and IHC4 algorithms provide such information, particularly when used in combination (IHC4+C). Their derivation in the translational cohort of the Arimidex Tamoxifen Alone or in Combination trial (TransATAC) was described by Cuzick et al in 2011. In the original model tumor size and nodal status were each classified into three categories, causing prognostic information to be lost.

METHODS

We modeled a novel CTSn algorithm on outcome data from patients in the anastrozole and tamoxifen arms in ATAC incorporating tumor size as a continuous variable and sub-dividing nodal status into five categories. IHC4n was re-derived in the TransATAC cohort independent of CTSn. Patients were chemotherapy-naïve. We compared ability to predict risk of residual distant recurrence of the new IHC4n+Cn model with that of the original one when tested in a training cohort and in a validation set of chemotherapy-naïve patients from the Tamoxifen vs. Exemestane Adjuvant Multicentre (TEAM) trial using Cox regression models and the C-index.

RESULTS

The ATAC training set for CTSn comprised 4056 patients, the TransATAC training set for IHC4n comprised 1125 patients; 2591 patients were in the TEAM validation set. Patients in the TEAM set were older (median age in TransATAC: 63.5, TEAM: 68.3 years), had a higher nodal-burden (node-positive in TransATAC: 29.4%, TEAM: 51.8%) and had more Grade 3 tumors (TransATAC: 18.3%, TEAM: 32.2%).

The new IHC4n+Cn was significantly prognostic, and non-significantly more prognostic than the original IHC4+C in both the training and validation cohorts. When assessed using the C-index statistic, IHC4n+Cn had a higher discriminatory ability than the original algorithm (Table 1).

Table 1 TransATAC (N=1125)TEAM (N=2591) HR* (95% CI)C-indexHR* (95% CI)C-indexOld Models    CTS2.26 (2.01-2.53)0.6811.88 (1.73-2.03)0.650IHC41.67 (1.46-1.91)0.6301.49 (1.35-1.63)0.604IHC4+C2.76 (2.40-3.18)0.7242.03 (1.87-2.21)0.671New Models    CTSn2.64 (2.26-3.09)0.7212.16 (1.96-2.39)0.687IHC4n1.74 (1.52-2.01)0.6421.51 (1.36-1.68)0.603IHC4n+Cn2.91 (2.47-3.42)0.7382.28 (2.06-2.51)0.695(*Hazard Ratio for change in one Standard Deviation).

CONCLUSION

By separately remodellng the part of the IHC4+C score based on clinicopathological characteristics using the whole ATAC chemo-naïve cohort, and the part that uses IHC-derived information in chemo-naïve TransATAC patients, we increased the precision of the individual risk estimates produced by both CTSn and IHC4n compared to those given by the original algorithms. The new IHC4n+Cn shows a trend for improved prognostic ability compared to the original IHC4+C. Like its predecessor, it relies on information that is readily available to clinicians and integrates it in an evidence-based way to improve prognostication in ER+ early breast cancer.

Citation Format: Dodson A, Sestak I, Bayani J, Dowsett M, Bartlett J, Cuzick J. A newly derived combined clinical treatment score and immunohistochemical-4 prognostic tool [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 P2-07-02.

Abstract P2-08-04: Prediction of distant recurrence by EndoPredict in patients with estrogen receptor-positive, HER2-negative breast cancer who received adjuvant endocrine therapy plus chemotherapy (ET+C) or endocrine therapy alone (ET)

Background: EndoPredict (EPclin) is a validated prognostic test combining expression of 12 cancer-related genes for breast cancer patients with estrogen receptor (ER) positive, HER2-negative disease who received 5 years of endocrine therapy (Buus et al., 2017; Dubsky et al. 2012) and for women who received chemotherapy (Martin et al., 2014). Here, we determine the EPclin and 10-year distant recurrence free interval (DRFI) rates for patients who received adjuvant endocrine therapy plus chemotherapy (ET+C) or endocrine therapy alone (ET) using data from five large clinical trials.

Methods: A total of 3746 women with ER-positive, HER2-negative disease were included in this analysis. 2630 patients received 5 years of ET alone (ABCSG-6/8, TransATAC) and 1116 patients received ET+C (GEICAM 2003-02/9906). EPclin incorporates tumor size and nodal status and accounts for different EPClin scores between ET+C and ET alone cohorts. The primary objective was to evaluate the 10-year DRFI rates as a continuous function of EPclin separately for patients in ET+C and ET. Secondary objectives included assessing the difference in the prognostic ability of EPclin between ET+C and ET overall (years 0-10) and for specific follow-up periods (years 0-5 and years 5-10). The primary endpoint was DRFI and the secondary endpoint was breast cancer free interval (BCFI). Cox proportional hazard models were used to estimate 10-year DRFI rates and to assess the prognostic information provided by EPclin.

Results: All of the women on ET alone and 49% of those on ET+C were postmenopausal. Women who received ET+C had more node positive disease, more poorly differentiated tumours, and higher EPclin scores than those who received ET alone. Women who received ET+C had significantly smaller increases in 10-year DRFI rates with increasing EPclin score than those receiving ET alone (Table). EPclin was highly prognostic for DRFI in all women who received ET alone (HR=2.79 (2.49-3.13), P<0.0001) as well as in those who received ET+C (HR=2.27 (1.99-2.59), P<0.0001), both in the overall cohort and in postmenopausal women only (ET+C: HR=2.64 (2.07-3.37), P<0.0001). We observed a significant interaction between EPclin and treatment for DRFI at 10 years (Pinteraction=0.022). EPclin was highly prognostic in ET alone and ET+C in years 0-5 and in particular in years 5-10. Similar results were observed when BCFI was the endpoint.

Conclusion: In our results from a non-randomized analysis, we observed significantly smaller increases in 10-year DRFI rates with increasing EPclin scores for women who received ET+C compared to those who received ET alone. Our indirect comparisons suggest that a high EPclin score can predict chemotherapy benefit in women with ER-positive, HER2-negative disease.

10-year DRFI risks (%) (95% CI) according to EPclin score for patients who received ET+C versus ET alone. ET+CETEPclin10-year DR risk (%)10-year DR risk (%)11.1% (0.5-1.7)1.0% (0.6-1.4)22.5% (1.5-3.5)2.8% (2.1-3.5)35.7% (4.1-7.2)7.6% (6.4-8.8)412.4% (10.1-14.6)19.8% (17.6-22.0)525.8% (22.0-29.5)46.1% (40.2-51.4)

Citation Format: Sestak I, Martin M, Dubsky P, Rojo F, Cuzick J, Filipits M, Ruiz A, Buus R, Hlauschek D, Rodriguez-Lescure A, Dowsett M, Gnant M. Prediction of distant recurrence by EndoPredict in patients with estrogen receptor-positive, HER2-negative breast cancer who received adjuvant endocrine therapy plus chemotherapy (ET+C) or endocrine therapy alone (ET) [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 P2-08-04.

Abstract P4-09-02: Validation of iPrevent using the prospective family study cohort (ProF-SC)

Background: iPrevent (https://www.petermac.org/iprevent) provides women with highly-tailored risk management information after first estimating their breast cancer (BC) risk using the established risk prediction models, IBIS and BOADICEA. iPrevent has an internal switching algorithm that governs which model is used for each woman, depending on her risk factor data (i.e. LCIS/atypical hyperplasia status, BRCA status, and cancer family history). This study assessed the calibration and discriminatory accuracy of the 10-year BC risk estimates provided by iPrevent. Methods: Subjects were 16,574 women in the ProF-SC, aged 18-70 years and without BC or bilateral mastectomy at recruitment. After 10 years follow-up, 655 women (4%) were diagnosed with invasive BC. A “batch mode” for iPrevent is not available, so the iPrevent-assigned cumulative 10-year invasive BC risks were calculated by entering self-reported risk factors at cohort entry into either the IBIS (10,169 women) or BOADICEA (6,405 women) software packages (according to the iPrevent switching algorithm). To assess calibration, the mean iPrevent-assigned risk was compared with the mean 10-year observed invasive BC incidence, using a chi-squared goodness-of-fit statistic for the whole cohort, and by quartiles of risk. To evaluate discriminatory accuracy, the overall area under the receiver operating characteristic curve (AUC) for the development of invasive BC within 10 years was computed. Data were censored at date of invasive or in situ BC diagnosis, bilateral mastectomy, death, loss to follow-up, or at 10 years of follow-up. Results: For the whole cohort, iPrevent assigned risk was well-calibrated – 690 expected BCs (E) 655 observed (O) (E/O=1.05, 95% CI: 0.98-1.14), although for women in the highest risk quartile, i.e. >6% 10-year risk, E/O=1.19, 95% CI: 1.07-1.32. The AUC was 0.70, 95% CI: 0.68-0.72. Conclusions: iPrevent is well calibrated overall and has good discriminatory accuracy for predicting 10-year BC risk, thus justifying its clinical use.

Citation Format: Phillips K-A, Liao Y, Collins IM, Buchsbaum R, Weideman P, Bickerstaffe A, MacInnis RJ, kConFab Investigators, Cuzick J, Antoniou A, Andrulis IL, John EM, Daly MB, Buys SS, Hopper JL, Terry MB. Validation of iPrevent using the prospective family study cohort (ProF-SC) [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 P4-09-02.

Abstract P3-08-01: Prognostic performance of EndoPredict in invasive lobular carcinoma

Background: Invasive lobular carcinomas (ILC) account for around 15% of all oestrogen receptor (ER) positive invasive breast cancers. The EndoPredict assay (EPclin) is a multigene classifier to predict the likelihood of distant recurrence in ER-positive, HER2-negative breast cancer patients treated with adjuvant endocrine therapy and has been validated in several retrospective translational studies. However, these validation studies did not include an analysis of the histological subtypes. Here, we investigate the role of EPclin for the prediction of distant recurrence in women with ILC and compare the prognostication to those with invasive ductal carcinoma (IDC) in TransATAC.

Methods: Data on EPclin and histological type of tumour were available for 928 postmenopausal women with ER-positive, HER2-negative disease treated with 5 years of tamoxifen or anastrozole. The primary endpoint was distant recurrence and the primary objective was to assess the prognostic value of EPclin for the prediction of distant recurrence in women with invasive lobular carcinoma. Kaplan–Meier and Cox regression analyses were used to determine distant recurrence risk for 0-10 years of follow-up. Likelihood ratio tests were used to assess the prognostic information provided by EPclin. Hazard Ratios (HR) are for a change in 1 Standard Deviation.

Results: 141 (15.2%) had ILC, 710 (76.5%) IDC, and the remaining 77 (8.3%) were of different histological type. EPclin provided highly significant prognostic value for distant recurrence in women with ILC (HR=3.33 (2.33-4.77), P<0.001; LR-χ2=38.4). For those with IDC, EPclin was highly prognostic for distant recurrence over 10 years of follow-up (HR=2.41 (2.04-2.84), P<0.001; LR-χ2=95.5). EPclin was more prognostic in IDC than ILC, and a significant interaction between EPclin and tumour type (ILC/IDC) was observed (P-interaction=0.038). 89 (63.1%) women with ILC were categorised into the low EPclin risk group and 52 (36.9%) into the high risk group. A highly significant separation between EPclin low and high risk groups was observed for ILC (10-year distant recurrence risk low: 6.2% (2.6-14.2) vs. high: 36.6% (24.2-52.1); HR=7.36 (2.71-20.01)). For women with IDC, 406 (57.2%) were categorised into the low risk group by EPclin and 304 (42.8%) were deemed high risk, with significant separation between risk groups (10-year distant recurrence risk low: 6.2% (4.1-9.3) vs. high: 28.5% (23.5-34.3); HR=5.59 (3.48-8.98)). We did not observe any differential efficacy of treatment between histological subtype and EPclin risk group.

Conclusions: This is the first analysis to focus on the role of EPclin for the prognostic assessment of women with ILC. Although numbers of women with ILC in TransATAC were small, EPclin provided highly significant prognostic information and risk stratification for this subgroup of women. 10-year distant recurrence risk in the EPclin low risk groups were similar between ILC and IDC, suggesting that chemotherapy is not indicated, irrespective of tumour type. Our results show that EPclin is informative in women with ILC.

Citation Format: Sestak I, Kronenwett R, Denkert C, Cuzick J, Dowsett M. Prognostic performance of EndoPredict in invasive lobular carcinoma [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 P3-08-01.

Abstract P4-08-01: Not presented

This abstract was not presented at the symposium.

Abstract P4-11-02: Acceptability and usability of iPrevent, a web-based decision support tool for assessment and management of breast cancer risk

Background: iPrevent estimates an individual's personal BC risk, using either the IBIS or BOADICEA algorithms, and provides tailored risk management information on screening, lifestyle modifications, risk-reducing surgery and risk-reducing medication. It is designed to be used collaboratively by women and their clinicians. The purpose of this pre-implementation pilot study was to assess the clinical usability and acceptability of the iPrevent prototype, and to identify barriers to clinical implementation. Exploratory aims investigated patients' BC worry, anxiety, risk perception and knowledge before and after using iPrevent. Methods: Eligible clinicians worked in primary care (PC), breast surgical (BS) or genetics clinics (GC). Their female patients were eligible if aged 18-70 years with no personal cancer history. Clinicians were familiarized with iPrevent using hypothetical cases, then actor scenarios, and lastly iPrevent was trialed with patients. All participants completed the System Usability Scale (SUS) and an acceptability questionnaire 2 weeks after using iPrevent. Patients also completed the Lerman BC Worry Scale, Spielberger State-Trait Anxiety Inventory, and BC risk perception and prevention knowledge questionnaires before and 2 weeks after using the tool. Data were summarized using descriptive statistics. Results: 63 participants comprising 20 clinicians (median age 47 years, 8 PC, 6 BS, 6 GC) and 43 patients (median age 38 years, 16% high risk, 51% moderate risk, 33% average risk) were recruited. Usability was rated above average (SUS score >68) by most clinicians (68%) and patients (76%). Most (79% of clinicians, 81% of patients) agreed iPrevent was 'easy to use', although 10 (53%) clinicians and 10 (27%) patients reported that it was too long. Most clinicians (84%) and patients (86%) found iPrevent 'very' or 'somewhat' helpful. 89% of participants reported that iPrevent provided the right amount of information. 5% reported to 'rarely' or 'not at all' worry about BC before iPrevent, and 29% after use. 25% of patients reported less impact of worrying about BC after iPrevent, 47% were unchanged and 28% reported more impact of worrying about BC after iPrevent use. State anxiety remained the same. 87% of patients correctly reported their risk category after using iPrevent® compared with 40% before. BC prevention knowledge improved for most questions. Conclusions: iPrevent has high usability and acceptability. Exploratory analyses suggest that iPrevent may also improve patients' BC risk perception and knowledge without adversely affecting anxiety or BC worry. Because concerns about length could be a barrier to implementation, data entry has been abbreviated in the modified version of iPrevent that will be publically available.

Citation Format: Phillips K-A, Lo L, Bressel M, Collins IM, Emery J, Weideman P, Keogh L, Steel E, Bickerstaffe A, Mann GB, Trainer A, Hopper JL, Antoniou AC, Cuzick J, Butow P. Acceptability and usability of iPrevent, a web-based decision support tool for assessment and management of breast cancer risk [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 P4-11-02.

Abstract GS6-01: Integration of clinical variables for the prediction of late distant recurrence in patients with oestrogen receptor positive breast cancer treated with 5 years of endocrine therapy

Background: The prediction of late distant recurrence (DR) is an important clinical goal for managing women with hormone receptor positive disease who have reached the end of 5 years' endocrine treatment without recurrence. Molecular profiles have produced conflicting results for the prediction of late DR. Here, we develop and validate a simple clinicopathological tool (Clinical Treatment Score post-5 years (CTS5)) to estimate the residual risk of DR after 5 years' endocrine treatment, which should help in discussions with patients about the potential benefits or not of continued endocrine therapy.

Patients and Methods: The ATAC dataset (N=4735) of postmenopausal women with oestrogen receptor (ER) positive breast cancer treated with 5 years' tamoxifen or anastrozole was used as a training cohort to establish a prognostic score for post-5-year risk of DR. CTS5 was based on five categories for nodal status, linear and quadratic terms for tumour size (capped at 30mm), three categories for grade, and continuous age. The validity of the CTS5 was tested in the BIG1-98 dataset (N=6711), which included postmenopausal women with ER-positive breast cancer treated with tamoxifen or letrozole (either monotherapy or sequential). Both cohorts included women who were alive and DR-free 5 years after randomization. Time to late DR, defined beginning at 5 years after ATAC or BIG 1-98 randomization, was the primary endpoint. Cox regression models estimated the prognostic performance of the CTS5. Hazard Ratios (HRs) are for a change of one Standard Deviation.

Results: The CTS5 model was a significant predictor for late DR in ATAC (HR=2.47 (95% CI, 2.24-2.73), P<0.001) and performed better than the established 0-10 year CTS model (Cuzick et al., JCO, 2011). CTS5 was confirmed as highly predictive for late DR in the BIG1-98 validation cohort (HR=2.07 (1.88-2.28), P<0.001). Of greatest importance was that CTS5 risk stratification defined in the training cohort as low (<5% risk of DR during years 5-10), intermediate (5-10% risk), high (>10% risk), identified 43% of the validation cohort as low risk, with an observed DR rate of 3.6% (95% CI 2.7-4.9) during years 5-10. Within nodal subgroups, 63% of node-negative were low risk with 3.9% (2.9-5.3) DR rate between years 5-10, and 24% having 1-3 nodes positive were low risk with 1.5% (0.5-3.8) DR rate between years 5-10. Separation of intermediate-risk from high-risk categories was also shown in the training set but improvements in calibration seem necessary for clinical utility for that assessment.

Conclusion: The CTS5 is a simple tool based on information that is readily available to all clinicians. It was more accurate in its prediction of DR risk in years 5-10 than the published CTS model. CTS5 was validated as highly prognostic for late DR in the independent BIG 1-98 study. The algorithm identified a subgroup of women with either node-negative disease or 1-3 positive nodes as having less than 1% per year risk of DR who could be advised of the limited value of extended endocrine therapy.

Citation Format: Sestak I, Regan M, Dodson A, Viale G, Thürlimann B, Colleoni M, Cuzick J, Dowsett M. Integration of clinical variables for the prediction of late distant recurrence in patients with oestrogen receptor positive breast cancer treated with 5 years of endocrine therapy [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 GS6-01.

Abstract P5-15-01: Participant-reported symptoms as predictors of long-term adherence of endocrine therapy in the International breast cancer intervention studies 2 (IBIS-2)

Background: Aromatase inhibitors (AIs) reduce the risk of breast cancer in women at increased risk and reduce recurrence in those with ductal carcinoma in situ (DCIS) (IBIS-2, MAP.3, NSABP B-33). The effectiveness of AIs depends on full adherence. We have previously reported adherence figures for the International Breast Cancer Intervention Studies 2 (IBIS-2) when 5 years of active treatment was not completed. Here, we assess reports of early symptoms on 5-year adherence with anastrozole in the prevention (versus placebo) and DCIS (versus tamoxifen) IBIS-2 after active treatment has been completed by all women.

Methods: In IBIS-2, 3864 postmenopausal women in the prevention study were randomised to placebo vs. anastrozole (1mg/day) and 2980 postmenopausal women with DCIS were randomised to tamoxifen (20mg/day) vs. anastrozole (1mg/day). Women were excluded from the analyses (n=491 [262 prevention; 229 DCIS]) due to breast cancer, death, major adverse events, or failure to initiate preventive therapy. Adherence (<4.5 years, ≥4.5 years) was calculated using the Kaplan-Meier method. The primary objective was to determine overall adherence to endocrine treatment in both studies separately. Secondary objectives were to estimate the effect of early symptoms (6 months visit) on adherence by study and by treatment arm separately.

Results: In the IBIS-2 prevention study (N=3615), overall adherence to treatment was 67.7% and was statistically not significantly different between anastrozole (66.5%) and placebo (69.0%) (OR=0.89 (0.78-1.03), P=0.11). Adherence was significantly lower regardless of treatment allocation for those who developed arthralgia (68.3% vs. 72.8%, P=0.008) or gynaecological symptoms (vaginal changes, irregular bleeding) (65.1% vs. 72.2%, P=0.007), but not for those who reported hot flushes (71.1% vs. 71.8%, P=0.92), compared with those who did not report these symptoms at 6 months. In the IBIS-2 DCIS study (N=2759), adherence to treatment was 70.1% overall (anastrozole (70.2%) or tamoxifen (70.0%) (OR=1.01 (0.86-1.19), P=0.92)). Women treated with anastrozole reported significantly more arthralgia (30.6% vs. 20.5%, P<0.001), but significantly fewer hot flushes (41.1% vs. 47.0%, P=0.002) and gynaecological symptoms (7.0% vs. 12.6%, P<0.001) compared with those on tamoxifen. However, none of these symptoms had an impact on adherence to either anastrozole or tamoxifen. In both studies, the majority of symptoms were of mild or moderate severity and we observed significant trends for lower adherence with increasing severity for all symptoms irrespective of allocated treatment arm.

Conclusions: In the IBIS-2 trials, we observed no significant differences in adherence between either anastrozole vs. placebo (prevention), or anastrozole vs. tamoxifen (DCIS). Significant associations between early symptoms and adherence were observed only in the prevention study, regardless of treatment allocation. Reporting symptoms in the first 6 months of preventive and adjuvant therapy is unlikely to explain non-adherence to medication. Further research is required to identify modifiable factors which may be altered by behavioural interventions to improve adherence.

Citation Format: Sestak I, Smith S, Sleeth M, Howell A, Cuzick J. Participant-reported symptoms as predictors of long-term adherence of endocrine therapy in the International breast cancer intervention studies 2 (IBIS-2) [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 P5-15-01.

Early participant-reported symptoms as predictors of adherence to anastrozole in the International Breast Cancer Intervention Studies II

Background

Anastrozole reduces breast cancer risk in women at high risk, but implementing preventive therapy in clinical practice is difficult. Here, we evaluate adherence to anastrozole in the International Breast Cancer Intervention Study (IBIS)-II prevention and ductal carcinoma in situ (DCIS) trials, and its association with early symptoms.

Patients and methods

In the prevention trial, 3864 postmenopausal women were randomized to placebo versus anastrozole. A total of 2980 postmenopausal women with DCIS were randomized to tamoxifen versus anastrozole. Adherence to trial medication was calculated using the Kaplan-Meier method and all P-values were two-sided.

Results

In the prevention trial, adherence was 65.8% [anastrozole (65.7%) versus placebo (65.9%); HR = 0.97 (0.87-1.09), P = 0.6]. Adherence was lower for those reporting arthralgia in the placebo group (P = 0.02) or gynecological symptoms in the anastrozole group (P = 0.003), compared with those not reporting these symptoms at 6 months. In the DCIS study, adherence was 66.7% [anastrozole (67.5%) versus tamoxifen (65.8%); HR = 1.06 (0.94-1.20), P = 0.4]. Hot flashes were associated with greater adherence in the anastrozole arm (P = 0.02). In both studies, symptoms were mostly mild or moderately severe, and adherence decreased with increasing severity for most symptoms. Drop-outs were highest in the first 1.5 years of therapy in both trials.

Conclusions

In the IBIS-II prevention and DCIS trials, over two-thirds of women were adherent to therapy, with no differences by treatment groups. Participants who reported specific symptoms in the IBIS-II prevention trial had a small but significant effect on adherence, which strengthened as severity increased. Strategies to promote adherence should target the first year of preventive therapy.

De-escalating and escalating treatments for early-stage breast cancer: the St. Gallen International Expert Consensus Conference on the Primary Therapy of Early Breast Cancer 2017

The 15th St. Gallen International Breast Cancer Conference 2017 in Vienna, Austria reviewed substantial new evidence on loco-regional and systemic therapies for early breast cancer. Treatments were assessed in light of their intensity, duration and side-effects, seeking where appropriate to escalate or de-escalate therapies based on likely benefits as predicted by tumor stage and tumor biology. The Panel favored several interventions that may reduce surgical morbidity, including acceptance of 2 mm margins for DCIS, the resection of residual cancer (but not baseline extent of cancer) in women undergoing neoadjuvant therapy, acceptance of sentinel node biopsy following neoadjuvant treatment of many patients, and the preference for neoadjuvant therapy in HER2 positive and triple-negative, stage II and III breast cancer. The Panel favored escalating radiation therapy with regional nodal irradiation in high-risk patients, while encouraging omission of boost in low-risk patients. The Panel endorsed gene expression signatures that permit avoidance of chemotherapy in many patients with ER positive breast cancer. For women with higher risk tumors, the Panel escalated recommendations for adjuvant endocrine treatment to include ovarian suppression in premenopausal women, and extended therapy for postmenopausal women. However, low-risk patients can avoid these treatments. Finally, the Panel recommended bisphosphonate use in postmenopausal women to prevent breast cancer recurrence. The Panel recognized that recommendations are not intended for all patients, but rather to address the clinical needs of the majority of common presentations. Individualization of adjuvant therapy means adjusting to the tumor characteristics, patient comorbidities and preferences, and managing constraints of treatment cost and access that may affect care in both the developed and developing world.

Abstract S6-05: Comprehensive comparison of prognostic signatures for breast cancer in TransATAC

Background: A number of prognostic signatures have been developed for the prediction of breast cancer recurrence in the past decade. We have developed two signatures (Clinical Treatment Score (CTS), four immunohistochemical markers (IHC4)) and validated four prognostic signatures (Oncotype Dx Recurrence Score (RS), PAM50-based Prosigna (ROR), Breast Cancer Index (BCI), and EndoPredict (EPclin)) in the TransATAC cohort. Here, we compare the prognostic performance of these six signatures for distant recurrence (DR) in years 0-10, and specifically in years 5-10 after treatment cessation.

Methods: 1231 postmenopausal women with hormone receptor positive and HER2-negative breast cancer had at least one test performed. Of these, 818 women had data on all six signatures available. IHC4, RS and BCI (linear) are molecular only signatures whereas CTS, ROR and EPclin include clinicopathological factors. The primary endpoint was DR and the primary objective was to compare the prognostic value of the six signatures in terms of DR for years 0-10, 0-5, and 5-10. Secondary objectives included the comparison of the prognostic performance for node-negative and node-positive patients separately and the additional prognostic performance of each signature to the others. Likelihood ratio statistics (LR-χ2) were used to assess the prognostic information of each signature alone or in combination with other signatures.

Results: Median follow-up for this analysis was 9.94 years (IQR 8.01-10.09) and a total of 126 DR were recorded. 818 women with HER2-negative disease for whom data of all six signatures were available were included in this analysis. For all patients, CTS and EPclin were the most prognostic signatures in years 0-10 (CTS: LR-χ2=124.9; EPclin: LR-χ2=116.2) and years 5-10 (CTS: LR-χ2=59.6; EPclin: LR-χ2=56.8) in the univariate analysis. The other four signatures performed similarly well in years 0-5, but of those only BCI and ROR provided substantial prognostic information in years 5-10 (BCI: LR-χ2=25.3; ROR: LR-χ2=43.8). In multivariate analyses comparing the added information of the molecular signatures over CTS, IHC4 and BCI provided the most information (IHC4: ΔLR-χ2=19.0; BCI: ΔLR-χ2=19.8). In node-negative patients (72.3%), the ROR showed the most prognostic value in years 0-10 (LR-χ2=48.6) and years 5-10 (LR-χ2=31.3) whereas the RS was least prognostic in this patient group. For patients with node-positive disease (27.7%), the CTS and EPclin were the most prognostic and the other four signatures provided much less prognostic information for this patient population (data not shown).

Conclusion: Overall, the CTS and EPclin were the most prognostic signatures for DR and also added significant prognostic value to the other scores in women with HER2-negative disease, primarily due to the incorporation of nodal status in these signatures. For women with node-negative disease, the ROR, BCI, and EPclin signatures provided most prognostic value whereas for those with positive nodes CTS and EPclin were most prognostic. Our analyses showed that the inclusion of clinic-pathological factors into gene signatures is highly important for deriving an accurate prognostic assessment, particularly in node-positive patients.

Citation Format: Sestak I, Buus R, Cuzick J, Dubsky P, Kronenwett R, Ferree S, Sgroi D, Schnabel C, Baehner R, Mallon E, Dowsett M. Comprehensive comparison of prognostic signatures for breast cancer in TransATAC [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 S6-05.

Abstract P2-09-03: Long-term comparison of anastrozole versus tamoxifen: Results from LATTE/ATAC

Background: Previous reports from the Anastrozole Tamoxifen Alone or in Combination (ATAC) trial have shown significantly prolonged disease-free survival, lower rates of recurrence and distant recurrence, and reduced contralateral breast cancer in patients treated with anastrozole compared to tamoxifen (Cuzick et al., Lancet, 2010). Here, we compare the long-term effects of anastrozole versus tamoxifen in patients randomised to either monotherapy arm in the ATAC trial.

Methods: Postmenopausal women with hormone receptor positive breast cancer randomised to anastrozole or tamoxifen in the main ATAC trial were eligible for the LATTE observational study. The primary objective was to compare the long-term effects of tamoxifen and anastrozole on time to recurrence and death beyond 10 years after randomisation. Secondary objectives included time to distant recurrence, cancer-specific survival, new breast primaries, other cancers, fractures, and cardiac/cerebrovascular events. Cox proportional hazard methods were used to compute hazard ratios (95% CI) for recurrence from the time of last publication (10 years median follow-up).

Results: 2452 women from 11 countries were entered into the LATTE study. 40 women withdrew consent and 759 women died or had a recurrence within 10 years, which left 1653 women for analysis (838 anastrozole vs. 815 tamoxifen). A total of 118 breast events (69 anastrozole (8.2%) vs. 49 tamoxifen (6.0%)) were reported. No significant difference between the two treatment arms were observed (HR=1.36 (0.94-1.97), P=0.098). 57 women had a distant recurrence (33 (3.9%) vs. 24 (2.9%)), 41 reported a loco-regional recurrence (23 (2.7%) vs. 18 (2.2%)), and 26 contra-lateral breast cancer were recorded (17 (2.0%) vs. 9 (1.1%)). None of the treatment comparisons were statistically significant. 305 deaths were recorded (147 (17.5%) vs. 158 (19.4%)), of which 31 were due to breast cancer. Significantly fewer gynaecological cancers were recorded with anastrozole (7 vs. 16; OR=0.42 (0.15-1.09), P=0.05), but overall the effect on other cancers was not significant (54 (6.4%) vs. 64 (7.9%). Fractures, cardiovascular, and cerebrovascular events were evenly distributed between the treatment arms.

Conclusions: Although anastrozole was associated with significant fewer recurrences compared to tamoxifen in the first 10 years of follow-up, in this analysis, with limited number of patients, we could not find a significant difference between the two treatment arms.

Citation Format: Cuzick J, Sestak I, Bianco A, Strobbe L, Bergh J, Hanusch C, Neven P, Dowsett M, Forbes JF, Buzdar A, Smith R, Howell A. Long-term comparison of anastrozole versus tamoxifen: Results from LATTE/ATAC [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 P2-09-03.

Abstract P1-09-06: Prognostic and predictive relevance of cell cycle progression (CCP) score in ductal carcinoma in situ: Results from the UK/ANZ DCIS trial

Background: The prognostic abilities of most gene expression signatures in breast cancer are often due to detection of proliferative activity measured from expression of genes regulated as a function of cell cycle progression. Cell Cycle Progression (CCP) score is an important prognostic factor in prostate cancer, and has shown promising results for renal and lung cancer; its role in ductal carcinoma in situ (DCIS) has not been explored. We investigated the prognostic and predictive relevance of CCP Score in DCIS using material from UK/ANZ DCIS trial.

Methods: Formalin-fixed paraffin embedded tissues were collected from patients enrolled in the UK/ANZ DCIS trial, a randomised 2X2 factorial design trial investigating role of tamoxifen, radiotherapy (RT) or both as adjuvant treatment in DCIS. mRNA expression of 25 S- and M-phase CCP genes was evaluated by reverse transcription followed by PCR on customized Taqman low-density arrays. CCP score is an un-weighted average of the expression values of CCP genes after normalisation with 14 housekeeping genes. CCP score was analysed as a continuous variable and also as an ordinal variable using tertile-based cut-offs. Exploratory analyses with subgroups defined by HER2 status by immunohistochemistry were performed.

Results: CCP scores were evaluable in 521 (134 recurrence events) of 704 available samples (DCIS absent or insufficient RNA in 51, assay failure in 132). Increase in CCP score (median 1.15; IQR 0.71-1.74) was associated with increased risk of ipsilateral breast event (IBE) [Hazard ratio (HR) = 1.28; 95% Confidence Interval (95%CI) 1.08-1.51; p = 0.0049]. CCP score however was not an independent predictor in multivariate analyses [HR = 1.16; 95%CI 0.95-1.42; p = 0.14].

CCP scores were categorised as CCP low (<0.87), CCP intermediate (>/= 0.87 to < 1.52) and CCP high (>/= 1.52) by tertiles. The benefit of RT in reducing IBE was significant when CCP score was low [HR = 0.35; 95%CI 0.14-0.87; p = 0.024] or intermediate [HR = 0.23; 95%CI 0.09-0.59; p = 0.0023], however, those with high CCP score did not derive significant RT benefit [HR = 0.59; 95%CI 0.31-1.13; p = 0.11].

In exploratory subgroup analyses, HER2 negative DCIS with high CCP score (20.9% of all DCIS cases) did not derive RT benefit and the largest RT benefit was seen for DCIS that expressed HER2 and did not have a high CCP score (23.2% of all DCIS cases).

Benefit of RT and 10-year IBE rates by CCP score (categorised) and HER2 status subgroups.SubgroupneventsHR (95%CI)p10-year IBE rates (%) - No RT10-year IBE rates (%) - RTCCP-high & HER2 neg106220.83 (0.35-1.97)0.6722.5 (14.0-35.0)20.0 (10.5-36.0)CCP-high & HER2 pos67210.43 (0.16-1.17)0.09840.6 (27.1-57.6)20.4 (8.9-42.9)CCP-non-High & HER2 neg217300.43 (0.18-0.99)0.04816.2 (10.7-24.0)8.1 (4.0-16.3)CCP- non-High & HER2 pos118330.14 (0.04-0.46)0.001239.5 (29.3-51.6)7.1 (2.3-20.4)CCP-non-High = low or intermediate CCP score

Conclusions: CCP score is not independently associated with the risk of IBE but appears to be a predictor of RT benefit. Exploratory analyses suggest that combined with HER2 status, it may help in identifying a large DCIS subgroup where RT is highly indicated and another large subgroup where mastectomy may be merited.

Citation Format: Thorat MA, Wagner S, Jones LJ, Levey PM, Bulka K, Hoff R, Sangale Z, Flake II DD, Bundred NJ, Fentiman IS, Forbes JF, Lanchbury JS, Cuzick J. Prognostic and predictive relevance of cell cycle progression (CCP) score in ductal carcinoma in situ: Results from the UK/ANZ DCIS trial [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 P1-09-06.

PIK3CA Mutation, Aspirin Use after Diagnosis and Survival of Colorectal Cancer. A Systematic Review and Meta-analysis of Epidemiological Studies

AIMS

Regular aspirin use has been associated with inhibition of the whole spectrum of colorectal carcinogenesis, including prevention of metastases and reduced total mortality in colorectal cancer. Preclinical data show that aspirin down-regulates PI3 kinase (PI3K) signalling activity through cyclo-oxygenase-2 (COX-2) inhibition, leading to the hypothesis that the effect of aspirin might be different according to PIK3CA mutational status, but epidemiological studies have led to conflicting results. The aim of this study was to assess the relationship between PIK3CA status and the efficacy of regular use of aspirin after diagnosis on overall survival in colorectal cancer patients.

MATERIALS AND METHODS

We identified studies that compared post-diagnosis aspirin efficacy in colorectal cancer patients identified by PIK3CA status. Hazard ratios for overall survival were meta-analysed according to PIK3CA status by inverse variance weighting. A pooled test for treatment by PIK3CA status interaction was carried out by weighted linear meta-regression. All statistical tests were two-sided.

RESULTS

The overall effect of aspirin was not significant (summary risk estimate = 0.82; 95% confidence interval 0.63-1.08, P = 0.16; I(2) = 57%). In PIK3CA mutant disease (n = 588), aspirin use reduced total mortality by 29% (summary risk estimate = 0.71; 95% confidence interval 0.51-0.99, P = 0.04; I(2) = 0%), whereas in PIK3CA wild-type disease (n = 4001), aspirin use did not reduce overall mortality (summary risk estimate = 0.93; 95% confidence interval 0.61-1.40; P = 0.7; I(2) = 80%) (P interaction = 0.39). There was a beneficial trend for aspirin on cancer-specific survival in PI3KCA mutated subjects (summary risk estimate = 0.37, 95% confidence interval 0.11-1.32, P = 0.1), albeit with high heterogeneity (Q chi-squared = 3.41, P = 0.07, I(2) = 70.7%).

CONCLUSION

These findings suggest that the benefit of post-diagnosis aspirin treatment on overall mortality in colorectal cancer may be more marked in PIK3CA mutated tumours, although the low number of studies prevents definitive conclusions. Trials addressing this issue are warranted to assess the efficacy of aspirin in the adjuvant setting.

Factors affecting uptake and adherence to breast cancer chemoprevention: a systematic review and meta-analysis

BACKGROUND

Preventive therapy is a risk reduction option for women who have an increased risk of breast cancer. The effectiveness of preventive therapy to reduce breast cancer incidence depends on adequate levels of uptake and adherence to therapy. We aimed to systematically review articles reporting uptake and adherence to therapeutic agents to prevent breast cancer among women at increased risk, and identify the psychological, clinical and demographic factors affecting these outcomes.

DESIGN

Searches were carried out in PubMed, CINAHL, EMBASE and PsychInfo, yielding 3851 unique articles. Title, abstract and full text screening left 53 articles, and a further 4 studies were identified from reference lists, giving a total of 57. This review was prospectively registered with PROSPERO (CRD42014014957).

RESULTS

Twenty-four articles reporting 26 studies of uptake in 21 423 women were included in a meta-analysis. The pooled uptake estimate was 16.3% [95% confidence interval (CI) 13.6-19.0], with high heterogeneity (I(2) = 98.9%, P < 0.001). Uptake was unaffected by study location or agent, but was significantly higher in trials [25.2% (95% CI 18.3-32.2)] than in non-trial settings [8.7% (95% CI 6.8-10.9)] (P < 0.001). Factors associated with higher uptake included having an abnormal biopsy, a physician recommendation, higher objective risk, fewer side-effect or trial concerns, and older age. Adherence (day-to-day use or persistence) over the first year was adequate. However, only one study reported a persistence of ≥ 80% by 5 years. Factors associated with lower adherence included allocation to tamoxifen (versus placebo or raloxifene), depression, smoking and older age. Risk of breast cancer was discussed in all qualitative studies.

CONCLUSION

Uptake of therapeutic agents for the prevention of breast cancer is low, and long-term persistence is often insufficient for women to experience the full preventive effect. Uptake is higher in trials, suggesting further work should focus on implementing preventive therapy within routine care.

Abstract S6-03: Anastrozole versus tamoxifen for the prevention of loco-regional and contralateral breast cancer in postmenopausal women with locally excised ductal carcinoma in-situ (IBIS-II DCIS)

Background: Third generation aromatase inhibitors are a more effective treatment option than tamoxifen for hormone receptor positive invasive breast cancer in postmenopausal women. However, it is not known whether anastrozole is more effective than tamoxifen in preventing the recurrence of breast cancer in women with hormone receptor (HR) positive ductal carcinoma in situ (DCIS). Here, we compare the efficacy of anastrozole versus tamoxifen in postmenopausal women with HR positive DCIS.

Methods: A multi-centre randomised placebo-controlled trial of 1mg/day anastrozole (oral) vs. 20mg/day tamoxifen (oral) for five years was conducted in 2980 postmenopausal women with locally excised HR positive DCIS. The primary endpoint was to determine if anastrozole is at least as effective as tamoxifen in loco-regional control and prevention of contralateral disease. Secondary endpoints included breast cancer mortality, other cancers, cardiovascular disease, fractures, adverse events and non-breast cancer deaths. All analyses were done on an intention-to-treat basis and Cox proportional hazard were used to compute hazard ratios and corresponding confidence intervals for recurrence.

Results: Between 2003 and 2012, a total of 2980 postmenopausal women were recruited into the IBIS-II DCIS trial. 1471 women were randomly assigned to receive anastrozole and 1509 women tamoxifen. Median follow-up for this first analysis is 6.8 years and 131 breast cancer recurrences have been recorded. Median age was 60.3 years (56.1-64.6), median BMI was 26.7 (23.6-30.7), and 45.6% of women had used hormone replacement therapy (HRT) before joining the trial. Of the 131 women with recurrent disease, 77 had a loco-regional recurrence and 51 reported contralateral disease. A total of 61 deaths were recorded. We will present a comprehensive analysis of the efficacy of anastrozole and tamoxifen for preventing loco-regional/contralateral breast cancer and major adverse events by intention to treat (ITT).

Conclusions: To follow.

Citation Format: Cuzick J, Forbes JF, Sestak I, Howell A, Bonanni B, Bundred N, Levy C, von Minckwitz G, Eiermann W, Neven P, Stierer M, Holcombe C, Coleman RE, Jones LJ, Ellis I. Anastrozole versus tamoxifen for the prevention of loco-regional and contralateral breast cancer in postmenopausal women with locally excised ductal carcinoma in-situ (IBIS-II DCIS). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr S6-03.

Abstract P3-07-02: Prognostic and predictive relevance of HER2 status in ductal carcinoma in situ: Results from the UK/ANZ DCIS trial

Background:

As compared to invasive breast cancer (IBC), HER2 is much more frequently overexpressed in ductal carcinoma in situ (DCIS). Unlike IBC, the prognostic significance of HER2 overexpression remains to be established in DCIS and large studies to investigate its predictive role are lacking. We investigated the prognostic and predictive relevance of HER2 protein and ERBB2 mRNA expression in DCIS using material from UK/ANZ DCIS trial.

Methods:

Formalin-fixed paraffin embedded tissues (FFPETs) were collected from patients enrolled in the UK/ANZ DCIS trial, a randomised 2X2 factorial design trial investigating role of tamoxifen, radiotherapy or both as adjuvant treatment in DCIS. ERBB2 mRNA expression was evaluated by reverse transcription followed by PCR on customized Taqman low-density arrays. ERBB2 mRNA expression was analysed as a continuous variable and also as a binary variable using a cut-off to reproduce HER2 expression distribution similar to that observed with immunohistochemistry (IHC). HER2 protein expression was evaluated by IHC using HercepTest™ and scored as per ASCO-CAP 2013 recommendations; HER2 equivocal (IHC2+) were grouped with HER2 negative (IHC 0 or 1+) for main analyses. Additional analyses using binary ERBB2 mRNA expression as a reflex test for HER2 IHC2+ were also performed.

Results:

HER2 protein expression was evaluable in 713 (181 events) of 755 available samples (DCIS absent or lost during assay in 42). ERBB2 mRNA expression was evaluable in 521 (134 events) of 704 available samples (DCIS absent or insufficient RNA in 51, assay failure in 132). Both results were available in 508 cases (130 events). Increase in ERBB2 mRNA expression (median 0.62; range 0.07-36.76) was associated with increased risk of in situ ipsilateral breast event (DCIS-IBE) [Hazard ratio (HR) = 1.07; 95% Confidence Interval (95%CI) 1.04-1.10; p &lt; 0.0001] but not with increased risk of invasive ipsilateral breast event (I-IBE) [HR = 1.03; 95%CI 0.97-1.10; p = 0.3209]. HER2 positivity by IHC was similarly associated with increased risk of DCIS-IBE [HR = 2.90; 95%CI 1.91-4.40; p &lt; 0.0001] but not with increased risk of I-IBE [HR = 1.40; 95%CI 0. 0.81-2.42; p = 0.2313]. Reclassification of HER2 IHC2+ cases using binary ERBB2 mRNA expression (46 as negative, 16 as positive; 18 expression data unavailable) further improved prognostic discrimination of HER2 IHC [ΔX2 (1d.f.) 5.51; p = 0.0189] for any recurrence. The effect of radiotherapy (RT) for reducing I-IBE was greater in HER2 positive (by ERBB2 mRNA expression) cases [HR = 0.24; 95%CI 0.07-0.83; p = 0.0237] as compared with HER2 negative cases [HR = 0.60; 95%CI 0.23-1.55; p = 0.2925]. Kaplan-Meier estimates of 10-year I-IBE rates with and without RT were 4.5% (2.5%-1.4%) and 15.8% (9.6%-25.3%) in HER2 positive DCIS; rates in HER negative DCIS were 5.2% (2.1%-2.4%) and 7.3% (4.3%-12.2%) respectively. The differential benefit of RT by HER2 status was also seen for reduction in DCIS-IBE.

Conclusions:

HER2 overexpression is associated with increased risk of DCIS-IBE but not of I-IBE. HER2 status is predictive of radiotherapy response with larger reductions in both I-IBE and DCIS-IBE seen in HER2 positive DCIS.

Citation Format: Thorat MA, Wagner S, Jones LJ, Levey PM, Bulka K, Hoff R, Sangale Z, Flake II DD, Bundred NJ, Fentiman IS, Forbes JF, Lanchbury JS, Cuzick J. Prognostic and predictive relevance of HER2 status in ductal carcinoma in situ: Results from the UK/ANZ DCIS trial. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-02.

Abstract P5-08-03: Prognostic impact of the combined risk groups by breast cancer index and HOXB13/IL17BR ratio in hormonal receptor positive, node negative breast cancer: A TransATAC study

Background: Breast Cancer Index (BCI) is a gene expression-based assay that reports two distinct results: 1) BCI predictive based on HoxB13/IL17BR ratio (H/I), and 2) BCI prognostic based on an algorithm incorporating H/I with the Molecular Grade index (MGI). Both biomarkers have been validated independently in randomized trial cohorts. However, integrated results to better correlate recurrence risk with endocrine response have not been evaluated. The aim of this post-hoc analysis was to examine patient outcomes within BCI prognostic and predictive groups using the translational arm of the Arimidex, Tamoxifen, Alone or in Combination trial (TransATAC).

Methods: Primary tumor samples (N=742) from hormonal receptor-positive, N0 breast cancer patients treated with 5 years of tamoxifen (TAM) or anastrozole (ANA) in the ATAC trial were examined. Kaplan-Meier analysis was used to examine the risk of distant recurrence (DR) in patient subgroups derived from BCI and H/I results. A separate series of clinical cases submitted for BCI testing (N=853) were analyzed to determine distribution of the combined BCI and H/I groups in clinical practice.

Results: Summary of patient distribution across the 6 BCI clinical subgroups showed that a large number of patients (331/742, 45%) were BCI low risk with low likelihood of benefit, whereas 108/742 (15%) of patients with endocrine responsive disease (High H/I) were classified as BCI low risk (Table 1). Kaplan-Meier analysis demonstrated that patients classified as BCI low risk had a very similar 10-year risk of DR irrespective of H/I status (H/I low: 5.5% vs. H/I high: 4.0%), indicating that prognosis was largely determined by BCI vs H/I.

Table 1: Distribution of BCI and H/I risk groups in TransATAC BCI: PrognosticH/I: PredictiveLow RiskIntermediate RiskHigh RiskTotalLow Likelihood3318717435 (59%)High Likelihood10895104307 (41%)Total439 (59%)182 (25%)121 (16%)742

In 853 node negative cases submitted for BCI clinical testing, the distribution of BCI and H/I risk groups were similar to that from the TransATAC cohort (Table 2).

Table 2: Distribution of BCI and H/I risk groups in clinical cases submitted for BCI testing BCI: PrognosticH/I: PredictiveLow RiskIntermediate RiskHigh RiskTotalLow Likelihood36410523492 (58%)High Likelihood96107158361 (42%)Total460 (54%)212 (25%)181 (21%)853

Discussion: Both prognostic and predictive components reported from the BCI assay may be used to stratify patients into 6 clinical subgroups based on prognostic risk of distant recurrence and endocrine responsiveness. Findings from this analysis indicate that patients classified as BCI low risk, regardless of H/I status, had sufficiently low DR rates and identifies patients that may be adequately treated with 5 years of endocrine therapy.

Citation Format: Zhang Y, Sestak I, Schroeder BE, Dowsett M, Cuzick J, Schnabel CA, Sgroi DC. Prognostic impact of the combined risk groups by breast cancer index and HOXB13/IL17BR ratio in hormonal receptor positive, node negative breast cancer: A TransATAC study. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-08-03.

Abstract PD1-08: Factors affecting uptake and adherence to breast cancer chemoprevention: A systematic review and meta-analysis

Chemoprevention is a risk reduction option for women who have increased risk of breast cancer. Selective Estrogen Receptor Modulators (SERMs) have been extensively tested, and alternative agents are being evaluated. Long-term adherence to chemoprevention is critical to obtaining the drug's full benefit. We systematically reviewed articles reporting uptake rates and adherence among healthy adult women, who were prescribed medication to prevent primary breast cancer. We also extracted data on the clinical, socio-demographic and psychological predictors of uptake and adherence.

Searches were performed in PubMed, CINAHL, EMBASE, and PsychInfo, yielding 3851 unique articles. Title, abstract and full text screening left 53 articles that met inclusion criteria, and a further 4 studies were identified from reference lists, giving a total of 57. The mean quality score using the Mixed Methods Appraisal Tool was 3 out of 4.

Thirty-one articles reported uptake, of which 14 tested predictors, and 23 reported adherence of which 11 tested predictors. Seven studies reported qualitative data. Most studies (50) involved SERMs, but 5 tested Aromatase Inhibitors, 1 tested Aspirin, 1 tested a statin. Twenty studies included data from a clinical setting, 35 reported trial data, and 2 reported both.

Twenty-four studies reporting 26 instances of uptake in 21,423 women were included in a meta-analysis. The pooled uptake estimate was 16.3% (95% CI, 13.6-19.0), with high heterogeneity (I^2=98.9%, p&lt;0.0001). Uptake was unaffected by study location or agent, but was significantly higher in trials (25.2% [95% CI, 18.3-32.2]) than in clinical settings (8.7% [95% CI, 6.8-10.9]). Factors associated with higher uptake in two or more studies included having an abnormal biopsy, a physician recommendation, higher objective risk, fewer side-effect or trial-related concerns, and older age. Heterogeneity in data collection prevented a meta-analysis of adherence. Data suggested adequate day-to-day adherence among women who initiated treatment, with 5/6 studies reporting ≥80% of medications being taken appropriately. Persistence over 3-12 months was also high, with 5/7 studies reporting that ≥80% women were still taking chemoprevention. Long-term persistence was lower, with only 1/10 studies reporting a persistence of ≥80% by 5-years. Factors associated with lower adherence or persistence included allocation to Tamoxifen (vs. placebo or Raloxifene), depression, smoking, and older age. Objective and subjective risk was a theme in all qualitative studies, although other topics involved in decision-making included concerns about medications (6/7), low knowledge (3/7), lack of information (2/7), and trial-related issues (2/7).

Chemoprevention uptake for the prevention of breast cancer is low, and long-term adherence is often insufficient for the full preventive effect. Uptake rates were higher in trials than in clinical settings, suggesting further work should focus on implementing chemoprevention within routine patient care. Further research is warranted to identify factors amenable to modification and to improve informed decision-making surrounding chemoprevention.

Citation Format: Smith SG, Sestak I, Forster A, Partridge A, Side L, Horne R, Wardle J, Cuzick J. Factors affecting uptake and adherence to breast cancer chemoprevention: A systematic review and meta-analysis. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr PD1-08.

Abstract S4-06: HER2 status as predictive marker for AI vs Tam benefit: A TRANS-AIOG meta-analysis of 12129 patients from ATAC, BIG 1-98 and TEAM with centrally determined HER2

There is now significant evidence emerging from the pivotal trials of AIs versus Tamoxifen (AIOG) demonstrating the value of meta-analysis of key clinical questions. The "Trans-AIOG" group has been tasked with the exploration of key molecular/biomarker questions that are pertinent to meta-analyses of biomarkers (past/present/future) in AIOG trials. HER2 has been long proposed as a marker of endocrine "resistance". Data from three trials, before the era of HER-directed therapy, suggest a potential role for HER2 to select patients for treatment with upfront AIs. However the individual trials lack power to test treatment-by-HER2 interaction due to sample size and low HER2+ve rates. A meta-analysis of the predictive value of HER2 status, specifically within the first 3 years of endocrine therapy, has the potential to inform patient selection for upfront or sequential strategies with AIs. The pre-existing standardization of methodology for HER2 (IHC/FISH) facilitates analysis of existing data from BIG-1-98, TEAM and ATAC for this key marker.

Analysis plan: Following a prospectively-designed analysis plan, patient-level data from 3 randomized phase III trials (ATAC, BIG 1-98, TEAM) comparing AIs to tamoxifen during the first 2-3 years of adjuvant treatment were collected at the CRCTU (Birmingham UK), accounting for both the established time-dependency of relapse in HER2+ve, anti-endocrine treated patients and to address the clinical question of "upfront" vs "sequential" strategies for AIs. For each trial, covariate-adjusted Cox models estimated HER2-by-treatment (AI vs Tam) interaction on distant recurrence-free interval-censored at 2-2.75 years follow-up. A meta-analysis of the HER2-by-treatment interaction terms and of treatment effects according to HER2 status was performed.

Results: 12129 patients with centrally-confirmed ER and HER2 status, 1092 (9%) HER2+ve, with 473 (4%; 111 among HER2+ve) distant recurrences were analyzed. The meta-analysis estimated a pooled HER2-by-treatment interaction of 1.61 (95% CI 1.01,2.57), reflecting treatment effect hazard ratio(AI/Tam) of HR=1.13 (0.75,1.71) among HER2+ve and HR=0.70 (0.56,0.87) among HER2-ve. There was heterogeneity among interaction terms (I-squared=59%, p=.09) that resulted from treatment effect heterogeneity among HER2+ve subgroup (I2=71%, p=.03), not the HER2-ve subgroup (I2=0%). The results for disease-free survival were similar.

Conclusion: An individual patient data meta-analysis across 3 trials (ATAC, BIG 1-98, TEAM) conducted prior to standard use of HER2-directed adjuvant therapy demonstrated a marginally-significant interaction between HER2 status and treatment with AIs vs Tamoxifen in the 2-2.75 years prior to potential "switching" between Tamoxifen and AIs. Patients with HER2-ve cancers experienced improved outcomes when treated with AIs vs Tamoxifen whilst patients with HER+ve cancers fared no better, or slightly worse, during AI treatment. However, the small number of HER2+ve cancers and events even in this meta-analysis may explain a large degree of heterogeneity in the treatment effects within the HER2+ve subgroups across the 3 trials. Other causes, perhaps related to subtle differences between AIs, cannot be excluded.

Citation Format: Bartlett JMS, Ahmed I, Regan MM, Sestak I, Mallon EA, Dell'Orto P, Thürlimann BJK, Seynaeve C, Putter H, Brookes CL, Forbes JF, Colleoni MA, Bayani J, van de Velde CJH, Viale G, Cuzick J, Dowsett M, Rea DW, On Behalf of the Translational Aromatase Inhibitor Overview Group (Trans-AIOG). HER2 status as predictive marker for AI vs Tam benefit: A TRANS-AIOG meta-analysis of 12129 patients from ATAC, BIG 1-98 and TEAM with centrally determined HER2. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr S4-06.

Observation versus late reintroduction of letrozole as adjuvant endocrine therapy for hormone receptor-positive breast cancer (ANZ0501 LATER): an open-label randomised, controlled trial

BACKGROUND

Despite the effectiveness of adjuvant endocrine therapy in preventing breast cancer recurrence, breast cancer events continue at a high rate for at least 10 years after completion of therapy.

PATIENTS AND METHODS

This randomised open label phase III trial recruited postmenopausal women from 29 Australian and New Zealand sites, with hormone receptor-positive early breast cancer, who had completed ≥4 years of endocrine therapy [aromatase inhibitor (AI), tamoxifen, ovarian suppression, or sequential combination] ≥1 year prior, to oral letrozole 2.5 mg daily for 5 years, or observation. Treatment allocation was by central computerised randomisation, stratified by institution, axillary node status and prior endocrine therapy. The primary outcome was invasive breast cancer events (new invasive primary, local, regional or distant recurrence, or contralateral breast cancer), analysed by intention to treat. The secondary outcomes were disease-free survival (DFS), overall survival, and safety.

RESULTS

Between 16 May 2007 and 14 March 2012, 181 patients were randomised to letrozole and 179 to observation (median age 64.3 years). Endocrine therapy was completed at a median of 2.6 years before randomisation, and 47.5% had tumours of >2 cm and/or node positive. At 3.9 years median follow-up (interquartile range 3.1-4.8), 2 patients assigned letrozole (1.1%) and 17 patients assigned observation (9.5%) had experienced an invasive breast cancer event (difference 8.4%, 95% confidence interval 3.8% to 13.0%, log-rank test P = 0.0004). Twenty-four patients (13.4%) in the observation and 14 (7.7%) in the letrozole arm experienced a DFS event (log-rank P = 0.067). Adverse events linked to oestrogen depletion, but not serious adverse events, were more common with letrozole.

CONCLUSION

These results should be considered exploratory, but lend weight to emerging data supporting longer duration endocrine therapy for hormone receptor-positive breast cancer, and offer insight into reintroduction of AI therapy.

CLINICAL TRIALS NUMBER

Australian New Zealand Clinical Trials Registry (www.anzctr.org.au), ACTRN12607000137493.

Statistical controversies in clinical research: long-term follow-up of clinical trials in cancer

Long-term follow-up is an important unmet need for the full analysis of new treatments for cancer. Earlier detection of cancer and more effective treatment have led to many more patients surviving for more than 5 and even 10 years, so that evaluating late recurrences and side-effects is an increasingly important issue. This is particularly relevant for oestrogen receptor-positive breast cancer, where the existence of late recurrences is well documented. However, survival for other cancers, notably prostate, colorectal and cervix cancer, has dramatically increased in recent years due to screening and better treatment of early lesions. Trials of preventive therapies have an even greater need for long follow-up. Here, we review these issues and suggest ways in which provision for long-term follow-up can be improved.

Identifying clinically relevant prognostic subgroups of postmenopausal women with node-positive hormone receptor-positive early-stage breast cancer treated with endocrine therapy: a combined analysis of ABCSG-8 and ATAC using the PAM50 risk of recurrence score and intrinsic subtype

BACKGROUND

In the adjuvant treatment of hormone receptor-positive (HR+) breast cancer, variables like tumour size, grade and nodal status have great impact on therapy decisions. As most node-positive patients with HR+ breast cancer currently receive adjuvant chemotherapy improved methods for characterization of individuals' metastasis risk are needed to reduce overtreatment.

PATIENTS AND METHODS

Tissue specimens from node-positive patients of the ABCSG-8 and ATAC trials who received adjuvant tamoxifen and/or anastrozole were included in this study. Analysing RNA from paraffin blocks using the PAM50 test, the primary objective was to evaluate the prognostic information of the risk of recurrence (ROR) score added to combined clinical standard variables in patients with one positive node (1N+) and in patients with two or three positive nodes (2-3N+), using log-likelihood ratio tests.

RESULTS

At a median follow-up of 9.6 years, distant metastases occurred in 97 (18%) of 543 node-positive patients. In a multivariate analysis, the PAM50-derived ROR score provided reliable prognostic information in addition to and beyond established clinical factors for 1N+ (P < 0.0001) and 2-3N+ patients (P = 0.0002). Ten-year distant recurrence risk was significantly increased in the high-risk compared with the low-risk group derived from ROR score for 1N+ [25.5%, 95% confidence interval (CI) 17.5% to 36.1%versus 6.6%, 95% CI 3.3% to 12.8%] and compared with the combined low/intermediate risk group for 2-3N+ patients (33.7%, 95% CI 25.5% to 43.8% versus 12.5%, 95% CI 6.6% to 22.8%). Additionally, the luminal A intrinsic subtype (IS) exhibited significantly lower risk of distant recurrence compared with the luminal B subtype in 1N+ and 2-3N+ patients.

CONCLUSION

PAM50 ROR score and IS can identify node-positive patient subgroups with limited risk of metastasis after endocrine therapy, for whom adjuvant chemotherapy can be spared. The PAM50 test is a valuable tool in determining treatment of node-positive early-stage breast cancer patients.

Validation of an RNA cell cycle progression score for predicting death from prostate cancer in a conservatively managed needle biopsy cohort

BACKGROUND

The natural history of prostate cancer is highly variable and difficult to predict accurately. Better markers are needed to guide management and avoid unnecessary treatment. In this study, we validate the prognostic value of a cell cycle progression score (CCP score) independently and in a prespecified linear combination with standard clinical variables, that is, a clinical-cell-cycle-risk (CCR) score.

METHODS

Paraffin sections from 761 men with clinically localized prostate cancer diagnosed by needle biopsy and managed conservatively in the United Kingdom, mostly between 2000 and 2003. The primary end point was prostate cancer death. Clinical variables consisted of centrally reviewed Gleason score, baseline PSA level, age, clinical stage, and extent of disease; these were combined into a single predefined risk assessment (CAPRA) score. Full data were available for 585 men who formed a fully independent validation cohort.

RESULTS

In univariate analysis, the CCP score hazard ratio was 2.08 (95% CI (1.76, 2.46), P<10(-13)) for one unit change of the score. In multivariate analysis including CAPRA, the CCP score hazard ratio was 1.76 (95% CI (1.44, 2.14), P<10(-6)). The predefined CCR score was highly predictive, hazard ratio 2.17 (95% CI (1.83, 2.57), χ(2)=89.0, P<10(-20)) and captured virtually all available prognostic information.

CONCLUSIONS

The CCP score provides significant pretreatment prognostic information that cannot be provided by clinical variables and is useful for determining which patients can be safely managed conservatively, avoiding radical treatment.

Background risk of breast cancer influences the association between alcohol consumption and mammographic density

Background:

Alcohol consumption has been suggested to increase risk of breast cancer through a mechanism that also increases mammographic density. Whether the association between alcohol consumption and mammographic density is modified by background breast cancer risk has, however, not been studied.

Methods:

We conducted a population-based cross-sectional study of 53 060 Swedish women aged 40–74 years. Alcohol consumption was assessed using a web-based self-administered questionnaire. Mammographic density was measured using the fully-automated volumetric Volpara method. The Tyrer–Cuzick prediction model was used to estimate risk of developing breast cancer in the next 10 years. Linear regression models were used to evaluate the association between alcohol consumption and volumetric mammographic density and the potential influence of Tyrer–Cuzick breast cancer risk.

Results:

Overall, increasing alcohol consumption was associated with higher absolute dense volume (cm³) and per cent dense volume (%). The association between alcohol consumption and absolute dense volume was most pronounced among women with the highest (⩾5%) Tyrer–Cuzick 10-year risk. Among high-risk women, women consuming 5.0–9.9, 10.0–19.9, 20.0–29.9, and 30.0–40.0 g of alcohol per day had 2.6 cm³ (95% confidence interval (CI), 0.2–4.9), 2.9 cm³ (95% CI, −0.6 to 6.3), 4.6 cm³ (95% CI, 1.5–7.7), and 10.8 cm³ (95% CI, 4.8–17.0) higher absolute dense volume, respectively, as compared with women abstaining from alcohol. A trend of increasing alcohol consumption and higher absolute dense volume was seen in women at low (⩽3%) risk, but not in women at moderate (3.0–4.9%) risk.

Conclusion:

Alcohol consumption may increase breast cancer risk through increasing mammographic density, particularly in women at high background risk of breast cancer.

Estimates of benefits and harms of prophylactic use of aspirin in the general population

BACKGROUND

Accumulating evidence supports an effect of aspirin in reducing overall cancer incidence and mortality in the general population. We reviewed current data and assessed the benefits and harms of prophylactic use of aspirin in the general population.

METHODS

The effect of aspirin for site-specific cancer incidence and mortality, cardiovascular events was collated from the most recent systematic reviews. Studies identified through systematic Medline search provided data regarding harmful effects of aspirin and baseline rates of harms like gastrointestinal bleeding and peptic ulcer.

RESULTS

The effects of aspirin on cancer are not apparent until at least 3 years after the start of use, and some benefits are sustained for several years after cessation in long-term users. No differences between low and standard doses of aspirin are observed, but there were no direct comparisons. Higher doses do not appear to confer additional benefit but increase toxicities. Excess bleeding is the most important harm associated with aspirin use, and its risk and fatality rate increases with age. For average-risk individuals aged 50-65 years taking aspirin for 10 years, there would be a relative reduction of between 7% (women) and 9% (men) in the number of cancer, myocardial infarction or stroke events over a 15-year period and an overall 4% relative reduction in all deaths over a 20-year period.

CONCLUSIONS

Prophylactic aspirin use for a minimum of 5 years at doses between 75 and 325 mg/day appears to have favourable benefit-harm profile; longer use is likely to have greater benefits. Further research is needed to determine the optimum dose and duration of use, to identify individuals at increased risk of bleeding, and to test effectiveness of Helicobacter pylori screening-eradication before starting aspirin prophylaxis.

Improving decision making about clinical trial participation - a randomised controlled trial of a decision aid for women considering participation in the IBIS-II breast cancer prevention trial

BACKGROUND

Decision aids may improve informed consent in clinical trial recruitment, but have not been evaluated in this context. This study investigated whether decision aids (DAs) can reduce decisional difficulties among women considering participation in the International Breast Cancer Intervention Study-II (IBIS-II) trial.

METHODS

The IBIS-II trial investigated breast cancer prevention with anastrazole in two cohorts: women with increased risk (Prevention), and women treated for ductal carcinoma in situ (DCIS). Australia, New Zealand and United Kingdom participants were randomised to receive a DA (DA group) or standard trial consent materials (control group). Questionnaires were completed after deciding about participation in IBIS-II (post decision) and 3 months later (follow-up).

RESULTS

Data from 112 Prevention and 34 DCIS participants were analysed post decision (73 DA; 73 control); 95 Prevention and 24 DCIS participants were analysed at follow-up (58 DA; 61 control). There was no effect on the primary outcome of decisional conflict. The DCIS-DA group had higher knowledge post decision, and the Prevention-DA group had lower decisional regret at follow-up.

CONCLUSIONS

This was the first study to evaluate a DA in the clinical trial setting. The results suggest DAs can potentially increase knowledge and reduce decisional regret about clinical trial participation.

Uptake of tamoxifen in consecutive premenopausal women under surveillance in a high-risk breast cancer clinic

BACKGROUND

Randomised trials of tamoxifen versus placebo indicate that tamoxifen reduces breast cancer risk by approximately 33%, yet uptake is low. Approximately 10% of women in our clinic entered the IBIS-I prevention trial. We assess the uptake of tamoxifen in a consecutive series of premenopausal women not in a trial and explore the reasons for uptake through interviews.

METHODS

All eligible women between 33 and 46 years at ≥17% lifetime risk of breast cancer and undergoing annual mammography in our service were invited to take a 5-year course of tamoxifen. Reasons for accepting (n=15) or declining (n=15) were explored using semi-structured interviews.

RESULTS

Of 1279 eligible women, 136 (10.6%) decided to take tamoxifen. Women >40 years (74 out of 553 (13.4%)) and those at higher non-BRCA-associated risk were more likely to accept tamoxifen (129 out of 1109 (11.6%)). Interviews highlighted four themes surrounding decision making: perceived impact of side effects, the impact of others' experience on beliefs about tamoxifen, tamoxifen as a 'cancer drug', and daily reminder of cancer risk.

CONCLUSIONS

Tamoxifen uptake was similar to previously ascertained uptake in a randomised controlled trial (IBIS-I). Concerns were similar in women who did or did not accept tamoxifen. Decision making appeared to be embedded in the experience of significant others.

Focal amplification of the androgen receptor gene in hormone-naive human prostate cancer

BACKGROUND

Androgen receptor (AR)-gene amplification, found in 20-30% of castration-resistant prostate cancer (CRPCa) is proposed to develop as a consequence of hormone-deprivation therapy and be a prime cause of treatment failure. Here we investigate AR-gene amplification in cancers before hormone deprivation therapy.

METHODS

A tissue microarray (TMA) series of 596 hormone-naive prostate cancers (HNPCas) was screened for chromosome X and AR-gene locus-specific copy number alterations using four-colour fluorescence in situ hybridisation.

RESULTS

Both high level gain in chromosome X (≥4 fold; n=4, 0.7%) and locus-specific amplification of the AR-gene (n=6, 1%) were detected at low frequencies in HNPCa TMAs. Fluorescence in situ hybridisation mapping whole sections taken from the original HNPCa specimen blocks demonstrated that AR-gene amplifications exist in small foci of cells (≤ 600 nm, ≤1% of tumour volume). Patients with AR gene-locus-specific copy number gains had poorer prostate cancer-specific survival.

CONCLUSION

Small clonal foci of cancer containing high level gain of the androgen receptor (AR)-gene develop before hormone deprivation therapy. Their small size makes detection by TMA inefficient and suggests a higher prevalence than that reported herein. It is hypothesised that a large proportion of AR-amplified CRPCa could pre-date hormone deprivation therapy and that these patients would potentially benefit from early total androgen ablation.

Abstract ES02-2: Who should receive preventive therapy?

Several options are now becoming available for preventive therapy in women at increased risk for breast cancer. A major challenge is to determine which women are at sufficiently high risk to warrant treatment, and who will benefit from such treatment. Standard risk factors have been combined in several models to develop a risk score, and the spread in 10-year risk associated with these models will be examined. Two new features which offer improved prognostic discrimination are breast density and SNP profiles. The former can be routinely read visually, but there is a substantial inter-reader variability, and a goal is to develop automated testing which is reproducible and highly prognostic for risk. SNP profiles consist of panels (now over 70) of low risk but common genes that individually are not useful, but as a panel may add useful information. A discussion of the relative amount of information in classic models, mammographic density, and SNP scores will be presented along with initial estimates of their combined utility. Lastly we look at markers which may be able to predict response to endocrine prophylactic treatment. Currently change in breast density offers the most promise in this arena.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr ES02-2.

Abstract S3-01: Breast cancer prevention using anastrozole in postmenopausal women at high risk

Background: Third generation aromatase inhibitors are the most effective endocrine treatment for hormone receptor positive breast cancer in postmenopausal women. Here, we assess the efficacy of anastrozole in postmenopausal women who do not have breast cancer, but are at high risk of developing the disease.

Methods: A multi-centre randomised placebo-controlled trial of 1mg/day oral anastrozole vs. matching placebo for five years was conducted in 3864 postmenopausal women at increased risk of breast cancer. The primary endpoint was the incidence of breast cancer (including ductal carcinoma in-situ (DCIS) and differences were assessed by the proportional hazards model. Detailed information on adverse events was collected.

Results: After a median follow up of 5.03 years, 125 breast cancers were recorded. A 53% reduction (95% CI (32-68%), P&lt;0.0001) was seen in the anastrozole arm. Significant reductions were seen for all invasive (50%), oestrogen receptor positive invasive (58%) and in situ tumours (70%). Fractures were non-significantly higher (8.5% vs. 7.7%, P = 0.3) and musculoskeletal events were significantly higher in the anastrozole arm (1226 vs. 1124, RR = 1.10 (1.05-1.16)) but were very common in both arms (63.9% vs. 57.8%). Vasomotor symptoms were also increased with anastrozole (RR = 1.15 (1.08-1.22)). Cancers at other sites were significantly decreased (40 vs. 70, RR = 0.58 (0.39-0.85)). Deaths from breast cancer and other causes were similar in both arms.

Conclusions: Anastrozole is an effective agent for reducing breast cancer incidence in postmenopausal women at high risk. Anastrozole was well tolerated and side effects associated with oestrogen deprivation were only slightly higher than for placebo.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr S3-01.

Prognostic value of PTEN loss in men with conservatively managed localised prostate cancer

Background:

The natural history of prostate cancer is highly variable and difficult to predict. We report on the prognostic value of phosphatase and tensin homologue (PTEN) loss in a cohort of 675 men with conservatively managed prostate cancer diagnosed by transurethral resection of the prostate.

Methods:

The PTEN status was assayed by immunohistochemistry (PTEN IHC) and fluorescent in situ hybridisation (PTEN FISH). The primary end point was death from prostate cancer.

Results:

The PTEN IHC loss was observed in 18% cases. This was significantly associated with prostate cancer death in univariate analysis (hazard ratio (HR)=3.51; 95% CI 2.60–4.73; P=3.1 × 10⁻¹⁴). It was highly predictive of prostate cancer death in the 50% of patients with a low risk score based on Gleason score, PSA, Ki-67 and extent of disease (HR=7.4; 95% CI 2.2–24.6; P=0.012) ), but had no prognostic value in the higher risk patients. The PTEN FISH loss was only weakly associated with PTEN IHC loss (κ=0.5). Both PTEN FISH loss and amplification were univariately predictive of death from prostate cancer, but this was not maintained in the multivariate analyses.

Conclusion:

In low-risk patients, PTEN IHC loss adds prognostic value to Gleason score, PSA, Ki-67 and extent of disease.

Mir143 expression inversely correlates with nuclear ERK5 immunoreactivity in clinical prostate cancer

Background:

Aberrant mitogen/extracellular signal-regulated kinase 5 (MEK5)–extracellular signal-regulated protein kinase 5 (ERK5)-mediated signalling has been implicated in a number of tumour types including prostate cancer (CaP). The mechanism for ERK5 activation in CaP remains to be fully elucidated. Studies have recently implicated the role of microRNA (miRNA) mir143 expression in the regulation of ERK5 expression.

Methods:

We utilised a tissue microarray (TMA) of 530 CaP cores from 168 individual patients and stained for both mir143 and ERK5. These TMAs were scored by a combination of observer and automated methods.

Results:

We observed a strong inverse relation between ERK5 and mir143, which manifested itself most strongly in the subgroup of 417 cores with non-zero mir143 and ERK5 immunoreactivity, or with only one of mir143 or ERK5 being zero (cc=0.2558 and P<0.0001). Mir143 neither correlate with Gleason scores or prostate-specific antigen levels, nor was it a predictor of disease-specific survival on univariate analysis.

Conclusion:

Although the mechanism for ERK5 activation in CaP remains to be fully elucidated, we have further validated the potential role of mir143 in regulating ERK5 levels in the clinical context. In addition, we demonstrate that the automated counting method for nuclear ERK5 is a clinically useful alterative to observer counting method in patient stratification in the context of ERK5 targeting therapy.

Prognostic value of Ki-67 for prostate cancer death in a conservatively managed cohort

Background:

Standard clinical parameters cannot accurately differentiate indolent from aggressive prostate cancer. Our previous work showed that immunohistochemical (IHC) Ki-67 improved prediction of prostate cancer death in a cohort of conservatively treated clinically localised prostate cancers diagnosed by transurethral resection of the prostate (TURP). Here, we present results in a more clinically relevant needle biopsy cohort.

Methods:

Biopsy specimens were microarrayed. The percentage of Ki-67 positively stained malignant cells per core was measured and the maximum score per individual used in analysis of time to death from prostate cancer using a Cox proportional hazards model.

Results:

In univariate analysis (n=293), the hazard ratio (HR) (95% confidence intervals) for dichotomous Ki-67 (⩽10%, >10%) was 3.42 (1.76, 6.62) χ² (1 df)=9.8, P=0.002. In multivariate analysis, Ki-67 added significant predictive information to that provided by Gleason score and prostate-specific antigen (HR=2.78 (1.42, 5.46), χ² (1 df)=7.0, P=0.008).

Conclusion:

The IHC Ki-67 scoring on prostate needle biopsies is practicable and yielded significant prognostic information. It was less informative than in the previous TURP cohort where tumour samples were larger and more comprehensive, but in more contemporary cohorts with larger numbers of biopsies per patient, Ki-67 may prove a more powerful biomarker.