The clinical implementation of polygenic risk scores (PGS) in comprehensive cancer risk assessments is imminent. The successful implementation relies on clear communication to consumers to facilitate understanding of personalised risk information and motivate cancer prevention behaviours. Development of provider- and consumer-friendly resources to aid communication and understanding of PGS results is a critical implementation task. This study aimed to produce an acceptable report for delivering comprehensive, PGS-informed breast cancer risk assessments in research and clinical settings. A two-phase, multi-methods research program was conducted, focusing on co-design with a broad group of interest holders to gather preferences and feedback on the content, layout and visual tools of a risk report. Phase 1 involved a literature review, a quantitative survey with consumers and qualitative interviews with consumers and medical practitioners to generate an initial prototype report. Phase 2 involved qualitative interviews with genetic counsellors to seek feedback about the prototype and refine it into a final version. The report was operationalised as a web-based application that generates personalised versions in PDF. The evidence-based, interest-holder-informed comprehensive breast cancer risk report produced is highly usable, able to support ongoing clinical implementation research on PGS across cancer use-cases and contexts. Future work should explore consumer evaluation of the report and the feasibility of interactive and digital delivery mechanisms.

Sexually transmitted infections (STIs) are continuing to rise in high-income countries, particularly among young adults. Increasing access to timely STI/HIV testing and treatment is key to reducing transmission. Web-accessed STI testing services have emerged as a pragmatic solution to improving access and uptake. However, these web-accessed alternatives do not always provide equivalent quality to in-person services. The scientific body of evidence around their development is limited and often not reported in detail, offering little guidance about design best practice. Translating a traditionally in-person service to a web-accessed one is a complex process that requires input from multiple stakeholders, including end users, clinical experts, and software developers, to support user acceptability, clinical safety, and technical feasibility. This manuscript outlines the evidence-based approach for establishing the clinical pathway for Test it, a statewide, publicly funded, web-accessed STI testing service targeting 16- to 29-year-olds in Victoria, Australia. We present the ten steps of the web-accessed clinical pathway and describe the iterative consultation and problem-solving process used to define them.

10524 Background: Request for bilateral mastectomy after a unilateral breast cancer (BC) diagnosis is increasing. In many cases the benefit of bilateral mastectomy is likely to be small and offset by substantial risks of morbidity, financial toxicity and overburdening of healthcare systems. It is difficult to accurately determine personal risk of developing a future BC. Existing risk prediction models only predict risk for contralateral BC. Australian consumers identified an unmet need for a model that estimates risk of developing BC in any residual breast tissue (ipsi- or contra-laterally); to help women diagnosed with unilateral BC make informed decisions about bilateral mastectomy. Methods: Data from 1,162 female BC cases participating in two Australian cohort studies were used to develop a model to predict risk of BC for women who developed a 1st invasive ER positive, HER2 negative BC after cohort entry or within 2 years prior to cohort entry. Women with a germline pathogenic variant in a BC predisposition gene, and those who received neoadjuvant systemic therapy were excluded. 187 (88 ipsilateral, 96 contralateral, 3 unknown laterality) BC events (161 invasive and 26 DCIS) occurred over a median follow-up of 13.8 years. Flexible parametric survival analysis was used, with time since diagnosis as the time scale, and death due to any cause considered as a competing event. Potential predictors of future BC risk were investigated, including age at 1st BC, age at 1st birth, parity, breastfeeding duration, menopausal hormone therapy use, BMI, number of 1st-degree relatives with BC, BC polygenic risk score (PRS-313), contralateral mammographic density, surgery (breast conservation vs unilateral mastectomy), tumor grade and size, number of positive axillary nodes, associated LCIS, and use of adjuvant chemotherapy or radiation. Retained in the final risk prediction algorithm (all P < 0.05) were age at diagnosis of 1st BC, surgery type, radiation therapy, family history, and PRS-313. For external validation of the model, data from 3,136 cases (eligibility criteria as per the training set) with 181 subsequent BC events participating in the international Breast Cancer Association Consortium were used. Calibration and a time-dependent area under the curve (AUC) at 10 years were assessed to determine model performance. Sensitivity analysis excluding PRS-313 was also performed (as it is usually not available in clinical practice). Results: Discriminatory ability at 10 years was AUC = 0.66 (95% CI 0.62-0.70) or 0.65 (95% CI 0.61-0.69) if PRS-313 was excluded. The model was well calibrated; expected (176 cases) to observed (181 cases) ratio = 0.97 (95% CI 0.84-1.13). Conclusions: This model provides valid estimates of 10-year BC risk after a 1st ER-positive HER2-negative BC and may be useful in collaborative decision-making between patients and their surgeons when considering bilateral mastectomy.

BACKGROUND:A risk-stratified approach to colorectal cancer (CRC) screening could result in a more acceptable balance of benefits and harms, and be more cost-effective.AIM:To determine the effect of a consultation in general practice using a computerised risk assessment and decision support tool (Colorectal cancer RISk Prediction, CRISP) on risk-appropriate CRC screening.DESIGN AND SETTING:Randomised controlled trial in 10 general practices in Melbourne, Australia, from May 2017 to May 2018.METHOD:Participants were recruited from a consecutive sample of patients aged 50-74 years attending their GP. Intervention consultations included CRC risk assessment using the CRISP tool and discussion of CRC screening recommendations. Control group consultations focused on lifestyle CRC risk factors. The primary outcome was risk-appropriate CRC screening at 12 months.RESULTS:A total of 734 participants (65.1% of eligible patients) were randomised (369 intervention, 365 control); the primary outcome was determined for 722 (362 intervention, 360 control). There was a 6.5% absolute increase (95% confidence interval [CI] = -0.28 to 13.2) in risk-appropriate screening in the intervention compared with the control group (71.5% versus 65.0%; odds ratio [OR] 1.36, 95% CI = 0.99 to 1.86, P = 0.057). In those due CRC screening during follow-up, there was a 20.3% (95% CI = 10.3 to 30.4) increase (intervention 59.8% versus control 38.9%; OR 2.31, 95% CI = 1.51 to 3.53, P<0.001) principally by increasing faecal occult blood testing in those at average risk.CONCLUSION:A risk assessment and decision support tool increases risk-appropriate CRC screening in those due screening. The CRISP intervention could commence in people in their fifth decade to ensure people start CRC screening at the optimal age with the most cost-effective test.

Background We developed a colorectal cancer risk prediction tool (‘CRISP’) to provide individualised risk-based advice for colorectal cancer screening. Using known environmental, behavioural, and familial risk factors, CRISP was designed to facilitate tailored screening advice to patients aged 50 to 74 years in general practice. In parallel to a randomised controlled trial of the CRISP tool, we developed and evaluated an evidence-based implementation strategy. Methods Qualitative methods were used to explore the implementation of CRISP in general practice. Using one general practice in regional Victoria, Australia, as a ‘laboratory’, we tested ways to embed CRISP into routine clinical practice. General practitioners, nurses, and operations manager co-designed the implementation methods with researchers, focussing on existing practice processes that would be sustainable. Researchers interviewed the staff regularly to assess the successfulness of the strategies employed, and implementation methods were adapted throughout the study period in response to feedback from qualitative interviews. The Consolidated Framework for Implementation Research (CFIR) underpinned the development of the interview guide and intervention strategy. Coding was inductive and themes were developed through consensus between the authors. Emerging themes were mapped onto the CFIR domains and a fidelity checklist was developed to ensure CRISP was being used as intended. Results Between December 2016 and September 2019, 1 interviews were conducted, both face-to-face and via videoconferencing (Zoom). All interviews were transcribed verbatim and coded. Themes were mapped onto the following CFIR domains: (1) ‘characteristics of the intervention’: CRISP was valued but time consuming; (2) ‘inner setting’: the practice was open to changing systems; 3. ‘outer setting’: CRISP helped facilitate screening; (4) ‘individual characteristics’: the practice staff were adaptable and able to facilitate adoption of new clinical processes; and (5) ‘processes’: fidelity checking, and education was important. Conclusions These results describe a novel method for exploring implementation strategies for a colorectal cancer risk prediction tool in the context of a parallel RCT testing clinical efficacy. The study identified successful and unsuccessful implementation strategies using an adaptive methodology over time. This method emphasised the importance of co-design input to make an intervention like CRISP sustainable for use in other practices and with other risk tools.

Rationale: The extent to which current asthma is a predictor of post-bronchodilator airflow obstruction (post-BD AO) in middle-age is not well defined. Aim: To develop a risk prediction model for post-BD AO (post-BD FEV1/FVC<LLN) in middle-aged Australians, and to compare individualized predictions in non-smokers which vary by asthma, age-of-onset and 10-year wheeze status. Methods: Predictor data (smoking, asthma, symptoms, sex, job-type) were from the Tasmanian Longitudinal Health Study (TAHS) cohort at age 41-45 years. Post-BD spirometry/ wheeze status were assessed at age 51-55 years. The model was developed using randomForest® Results: Of n=2,338, 12.9% had current asthma at mean age 43, while 7.3% had wheeze and 4.6% had post-BD AO at age 53. The model’s area under the receiver operator characteristic curve was 80% (95%PI:79–81%), sensitivity 78% (84/107 actual cases) and specificity 66% giving a 98% negative and 10% positive predictive value. For example, a female non-smoking cleaner who reported childhood asthma and wheeze at age 43 had a 10-year predicted probability for post-BD AO of 6.1% if she also reported wheeze at age 53 (predicted occurrence of 1 in 16). The risk was slightly less (5.6%) if wheeze at age 53 was absent. The same pattern was seen for adult-onset asthma (5.7% and 5.2% respectively). Risks were 1.4% for non-asthma and 2.4% for remitted asthma. Conclusion: Our 10-year prediction model has good discriminatory ability but many of those identified did not have lung function consistent with COPD, partly due to a low prevalence in this middle-aged population. For middle-aged non-smokers, the predictions suggest a low-moderate risk for current asthma.

BackgroundClassifying individuals at high chronic obstructive pulmonary disease (COPD)-risk creates opportunities for early COPD detection and active intervention.ObjectiveTo develop and validate a statistical model to predict 10-year probabilities of COPD defined by post-bronchodilator airflow obstruction (post-BD-AO; forced expiratory volume in 1 s/forced vital capacity<5th percentile).SettingGeneral Caucasian populations from Australia and Europe, 10 and 27 centres, respectively.ParticipantsFor the development cohort, questionnaire data on respiratory symptoms, smoking, asthma, occupation and participant sex were from the Tasmanian Longitudinal Health Study (TAHS) participants at age 41–45 years (n=5729) who did not have self-reported COPD/emphysema at baseline but had post-BD spirometry and smoking status at age 51–55 years (n=2407). The validation cohort comprised participants from the European Community Respiratory Health Survey (ECRHS) II and III (n=5970), restricted to those of age 40–49 and 50–59 with complete questionnaire and spirometry/smoking data, respectively (n=1407).Statistical methodRisk-prediction models were developed using randomForest then externally validated.ResultsArea under the receiver operating characteristic curve (AUCROC) of the final model was 80.8% (95% CI 80.0% to 81.6%), sensitivity 80.3% (77.7% to 82.9%), specificity 69.1% (68.7% to 69.5%), positive predictive value (PPV) 11.1% (10.3% to 11.9%) and negative predictive value (NPV) 98.7% (98.5% to 98.9%). The external validation was fair (AUCROC75.6%), with the PPV increasing to 17.9% and NPV still 97.5% for adults aged 40–49 years with ≥1 respiratory symptom. To illustrate the model output using hypothetical case scenarios, a 43-year-old female unskilled worker who smoked 20 cigarettes/day for 30 years had a 27% predicted probability for post-BD-AO at age 53 if she continued to smoke. The predicted risk was 42% if she had coexistent active asthma, but only 4.5% if she had quit after age 43.ConclusionThis novel and validated risk-prediction model could identify adults aged in their 40s at high 10-year COPD-risk in the general population with potential to facilitate active monitoring/intervention in predicted ‘COPD cases’ at a much earlier age.

Background Many older adults are sexually active, and STIs are rising amongst this cohort. In primary care, sexual health discussions are limited as health-care practitioners commonly assume older patients aged 60+ are not sexually active or are unwilling to discuss sex. Studies have either examined patient or clinician views, but not both. Objective This study investigates sexual health discussions in general practice. It is unique in that it sought perspectives of different groups: older patients, health-care professionals and key informants. Results Qualitative interviews revealed that older patients expect clinicians to bring up sexual concerns, whereas clinicians prefer older patients to do so. A simple electronic solution to circumvent this impasse was suggested and discussed. Conclusions Older adults would like to discuss sexual concerns with their health-care providers. Given the rising rates of STIs in later life, sexual health discussions with older patients must become part of routine care.

OBJECTIVE:Australia and New Zealand have the highest incidence of colorectal cancer (CRC) globally. Our research team has developed a CRC risk prediction tool for use in primary care to increase targeted screening. This study, Colorectal cancer RISk Prediction tool - patient ('CRISP-P'), aimed to determine the following to inform a future trial design: (i) the feasibility of self-reporting; (ii) the feasibility of recruitment methods; and (iii) the prevalence of CRC risk.METHODS:Participants aged between 40 and 75 years were recruited consecutively from three primary care waiting rooms. Participants input data into CRISP on a tablet without receiving clinical advice. Feasibility was evaluated using recruitment rate, timely completion, a self-reported 'ease-of-use', score and field notes. Prevalence of CRC risk was calculated using the CRISP model.RESULTS:Five hundred sixty-one (90%) patients agreed to use the tool and 424 (84%) rated the tool easy to use. Despite this, 41% of people were unable to complete the questions without assistance. Patients who were older, without tertiary education or with English as their second language were more likely to require assistance (P < 0.001). Thirty-nine percent of patients were low risk, 58% at slightly increased and 2.4% were at moderately increased risk of developing colorectal cancer in the next 5 years.CONCLUSIONS:The tool was perceived as easy to use, although older, less educated people, and patients with English as their second language needed help. The data support the recruitment methods but not the use of a self-completed tool for an efficacy trial.

BACKGROUND:In Australia, evidence-based guidelines recommend that women consider taking selective oestrogen receptor modulators (SERMs) to reduce their risk of breast cancer. In practice, this requires effective methods for communicating the harms and benefits of taking SERMs so women can make an informed choice.AIM:To evaluate how different risk presentations influence women's decisions to consider taking SERMs.DESIGN AND SETTING:Cross-sectional, correlational study of Australian women in general practice.METHOD:Three risk communication formats were developed that included graphics, numbers, and text to explain the reduction in breast cancer risk and risk of side effects for women taking SERMs (raloxifene or tamoxifen). Women aged 40-74 years in two general practices were shown the risk formats using vignettes of hypothetical women at moderate or high risk of breast cancer and asked to choose 'If this was you, would you consider taking a SERM?' Descriptive statistics and predictors (risk format, level of risk, and type of SERM) of choosing SERMs were determined by logistic regression.RESULTS:A total of 288 women were recruited (an 88% response rate) between March and May 2017. The risk formats that showed a government statement and an icon array were associated with a greater likelihood of considering SERMs relative to one that showed a novel expected frequency tree. Risk formats for raloxifene and for the high-risk vignettes were also more strongly associated with choosing to consider SERMs. No associations were found with any patient demographics.CONCLUSION:Specific risk formats may lead to more women considering taking SERMs to reduce breast cancer risk, especially if they are at high risk of the condition. Raloxifene may be a more acceptable SERM to patients.

Background New Australian guidelines recommend that GPs actively consider prescribing low-dose aspirin to patients aged 50-70 years to reduce their risk of developing colorectal cancer (CRC). Patients and GPs need to understand the relative benefits and harms to support informed decision making. Aim To develop and examine different methods to communicate the benefits and harms of taking aspirin for CRC prevention. Design and setting A cross-sectional, vignette study with patients aged 50-70 years consecutively recruited from general practices in Melbourne, Australia, between July and August 2018. Method Summary estimates from meta-analyses of the effects of aspirin on the incidence of CRC, cardiovascular disease. gastrointestinal bleeding, and incidence rates in the Australian population to estimate outcomes in a hypothetical population of 10 000 people aged 50-70 years. These estimates were presented using four different risk communication formats. Participants were shown these different formats and asked if they would take aspirin to prevent CRC. Results A total of 313 participants were recruited (95.1% recruitment rate), of whom 304 completed the study. Most participants (71.7-75.3%) reported they would take aspirin irrespective of risk format presented. Bar charts (odds ratio (OR) 1.20, 95% confidence intervals [CI] = 1.01 to 1.44) and expected frequency trees (OR 1.18, 95% CI = 0.99 to 1.41) were more strongly associated with the intentions to take aspirin compared with icon arrays. Bar charts were most preferred for presenting risk information. Conclusion A large proportion of participants in this study intended to take aspirin to reduce their CRC risk regardless of risk communication format. Bar charts and expected frequency trees were the preferred methods to present the benefits and harms of taking aspirin to prevent CRC.

Abstract 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.

Our aim was to estimate how long-term mortality following breast cancer diagnosis depends on age at diagnosis, tumor estrogen receptor (ER) status, and the time already survived. We used the population-based Australian Breast Cancer Family Study which followed-up 1,196 women enrolled during 1992-1999 when aged <60 years at diagnosis with a first primary invasive breast cancer, over-sampled for younger ages at diagnosis, for whom tumor pathology features and ER status were measured. There were 375 deaths (median follow-up = 15.7; range = 0.8-21.4, years). We estimated the mortality hazard as a function of time since diagnosis using a flexible parametric survival analysis with ER status a time-dependent covariate. For women with ER-negative tumors compared with those with ER-positive tumors, 5-year mortality was initially higher (p < 0.001), similar if they survived to 5 years (p = 0.4), and lower if they survived to 10 years (p = 0.02). The estimated mortality hazard for ER-negative disease peaked at ~3 years post-diagnosis, thereafter declined with time, and at 7 years post-diagnosis became lower than that for ER-positive disease. This pattern was more pronounced for women diagnosed at younger ages. Mortality was also associated with lymph node count (hazard ratio (HR) per 10 nodes = 2.52 [95% CI:2.11-3.01]) and tumor grade (HR per grade = 1.62 [95% CI:1.34-1.96]). The risk of death following a breast cancer diagnosis differs substantially and qualitatively with diagnosis age, ER status and time survived. For women who survive >7 years, those with ER-negative disease will on average live longer, and more so if younger at diagnosis.

Abstract Background iPrevent is an online breast cancer (BC) risk management decision support tool. It uses an internal switching algorithm, based on a woman’s risk factor data, to estimate her absolute BC risk using either the International Breast Cancer Intervention Study (IBIS) version 7.02, or Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm version 3 models, and then provides tailored risk management information. This study assessed the accuracy of the 10-year risk estimates using prospective data. Methods iPrevent-assigned 10-year invasive BC risk was calculated for 15 732 women aged 20–70 years and without BC at recruitment to the Prospective Family Study Cohort. Calibration, the ratio of the expected (E) number of BCs to the observed (O) number and discriminatory accuracy were assessed. Results During the 10 years of follow-up, 619 women (3.9%) developed BC compared with 702 expected (E/O = 1.13; 95% confidence interval [CI] =1.05 to 1.23). For women younger than 50 years, 50 years and older, and BRCA1/2-mutation carriers and noncarriers, E/O was 1.04 (95% CI = 0.93 to 1.16), 1.24 (95% CI = 1.11 to 1.39), 1.13 (95% CI = 0.96 to 1.34), and 1.13 (95% CI = 1.04 to 1.24), respectively. The C-statistic was 0.70 (95% CI = 0.68 to 0.73) overall and 0.74 (95% CI = 0.71 to 0.77), 0.63 (95% CI = 0.59 to 0.66), 0.59 (95% CI = 0.53 to 0.64), and 0.65 (95% CI = 0.63 to 0.68), respectively, for the subgroups above. Applying the newer IBIS version 8.0b in the iPrevent switching algorithm improved calibration overall (E/O = 1.06, 95% CI = 0.98 to 1.15) and in all subgroups, without changing discriminatory accuracy. Conclusions For 10-year BC risk, iPrevent had good discriminatory accuracy overall and was well calibrated for women aged younger than 50 years. Calibration may be improved in the future by incorporating IBIS version 8.0b.

Australia and New Zealand have the highest incidence rates of colorectal cancer worldwide. In Australia there is significant unwarranted variation in colorectal cancer screening due to low uptake of the immunochemical faecal occult blood test, poor identification of individuals at increased risk of colorectal cancer, and over-referral of individuals at average risk for colonoscopy. Our pre-trial research has developed a novel Colorectal cancer RISk Prediction (CRISP) tool, which could be used to implement precision screening in primary care. This paper describes the protocol for a phase II multi-site individually randomised controlled trial of the CRISP tool in primary care.

Background and objectives:Older patients want to discuss sexualhealth with general practitioners (GPs)but feel uncomfortable doing so, asdo their GPs. Online and digital aids(ODAs) are used in other clinicalcontexts and could provide an effectivetool to overcome this discomfort. Theaim of this study was to explore healthpractitioners’ views on the type of ODAthat could be used to facilitate sexualhealth discussions between olderpatients (aged ≥60 years) and healthpractitioners.Methods:Thirty-seven interviews were conductedin Victoria, Australia, between Marchand June 2017. Participants comprised15 GPs, 12 practice nurses or practicemanagers and 10 key informants (fivein sexual health, five in ODAs).Results:Most ODAs currently available targetyounger populations. Checklists orself‑service kiosks may provideeffective means to facilitate sexualhealth discussions with older patientsin primary care.Discussion:ODAs are acceptable and feasible toimplement in younger populations butneed testing with older patients. Healthprofessionals need training to deal withsexual health matters arising from usingsuch aids.

Abstract 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.