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Background: Tumour immunoprofiling captures tumour-microenvironment interactions and enables precision medicine. Multiplex immunofluorescence (mIF) imaging can provide comprehensive quantitative and spatial information for multiple immune markers. However, application at scale to clinical trial samples sourced from multiple institutions is challenging due to pre-analytical heterogeneity. Methods: We analysed 12'592 tissue microarray (TMA) spots from 3'545 colorectal cancers (CRC) sourced from more than 240 institutions in two clinical trials (QUASAR 2 and SCOT) stained for CD4, CD8, CD20, CD68, FoxP3, pan-cytokeratin and DAPI by mIF. TMA cores were multi-spectrally imaged by digital pathology and analysed by cell-based and pixel-based marker analysis. We developed and validated an adaptive thresholding method to account for inter- and intra-slide intensity variation in TMA analysis, compared the numerical results between analysis approaches and validated against the current gold standard of single-plex chromogenic immunohistochemistry (IHC). Results: Adaptive thresholding at a slide and spot level effectively ameliorated inter- and intra-slide intensity variation enabling high-throughput analysis of mIF-stained TMA cores by digital pathology and improving the image analysis results compared to methods using a single global threshold. Comparison of our mIF approach with CD8 IHC data derived from subsequent sections indicates the validity of our method (Spearman's rank correlation coefficients (SCC) between 0.63 and 0.66, p-value << 0.01). Evaluation of correlation between cell-based and pixel-based analysis results confirms equivalency (SCC > 0.8, p<< 0.01, except for CD20 in epithelium region) of both analytical approaches for precision immunoprofiling by mIF. Conclusions: This study reports an analytical approach to the largest multiparameter immunoprofiling study of clinical trial samples to date and establishes an adaptive thresholding method to account for inter- and intra-slide variation introduced by pre-analytical heterogeneity. This approach can enable the application of mIF immunoprofiling of clinical trial TMA datasets at scale.

IntroductionIt has been suggested that health economists need to adapt their methods in order to meet the challenges of evaluating molecular diagnostics. The aim of this review is to categorize and critically examine the challenges and methodological developments identified from the literature and to suggest how such challenges may be addressed.MethodsWe identified challenges and suggested methodological improvements using a systematic rapid review of the literature. We categorized challenges into those common to all economic evaluations, those common to all diagnostic technologies and those relevant to molecular diagnostics. We assessed whether development in the methods of economic evaluation or alternative action was required.ResultsWe found forty-one papers which identified twelve challenges. Choice of perspective and time-horizon were challenges common to all economic evaluations. Five challenges were relevant for all diagnostic technologies: complexity of analysis; range of costs; under-developed evidence base; behavioral aspects; and choice of outcome metrics. The final five challenges were specific to molecular diagnostics: heterogeneity of tests and platforms; increasing stratification; capturing personal utility; incidental findings and spill-over effects. The final five challenges may require methodological development. For example, although methods exist to capture the value of a diagnostic test over and above any health gain captured in a quality adjusted life year (‘personal utility’), there is currently no agreed method of incorporating this into a cost-utility analysis. For the other challenges development of evaluation processes is key. In particular, the weak evidence base for diagnostic technologies may require processes to evolve.ConclusionsCurrent methods of economic evaluation are generally able to cope with molecular diagnostics although a renewed focus on specific decision-makers’ needs and a willingness to move away from cost-utility analysis may be required. A key issue is the under-developed evidence-base and it may be necessary to rethink translation processes to ensure sufficient, relevant evidence is available to support economic evaluation and adoption of molecular diagnostics.

Background The undergraduate five-year MBChB programme at the University of Glasgow has a high volume of pathology teaching integrated into the course. The ability to better understand what pathology is taught and when, so as to build a picture of the types and depth of pathology topics covered across the programme stages is crucial, especially in a spiral curriculum. A novel method of curriculum mapping, known as curriculum heat mapping, was developed as a way to visualise where and when topics are taught, in an easier to understand format.Methods This method involved comparing the Glasgow curriculum to a pre-determined standard of what should be taught. In this case, The Royal College of Pathologists’ ‘Pathology Undergraduate Curriculum’ was used as a comparison of what a graduating doctor should know about pathology. Results Following the developed template, heat maps showcasing the range of pathology topics covered, and where they are covered, were developed for local use. These heat maps provided a clear visual representation of where and when topics are taught, and how they cluster.Conclusions Heat mapping is a novel low-cost, high-input method of curriculum mapping. It requires a person to input the data which can take a long time for large curricula. There are no other upfront financial costs. It can be used in any area with a curriculum and an external or internal comparator. Examples of gold standard external comparators include validated national or international curricula.Heat mapping can help integrated, spiral curriculum programmes to identify where core topics are taught throughout their course. The heat maps themselves successfully demonstrate the required information and are easy to interpret. The process of mapping, as well as the final heat map, can yield important information. This includes information about trends within the curriculum, areas for potential improvement in sessional design and a clearer understanding of the depth to which each topic is covered in each lecture.Overall, it is a viable novel method, which has been successful locally and is easily transferable to other areas such as pharmacology.

196 Background: The ESMO clinical practice guidelines recommend consideration of Immunoscore (IS) for risk assessment of early colon cancer patients. IS clinical performance was assessed in the SCOT and IDEA-HORG trials evaluating 3 vs. 6 months (3m vs. 6m) of mFOLFOX6 adjuvant chemotherapy in stage III colorectal cancer (CRC). Methods: 1,002 formalin-fixed paraffin-embedded (FFPE) tumor samples (762 from SCOT;240 from HORG) were collected, of which 851 were eligible for biomarker analysis. Eligible samples were classified into 2 groups using pre-defined cut-offs (IS-Low, IS- High) and the performance of IS to predict 3 year disease-free survival (3y-DFS) was evaluated. Results: IS was successfully assessed in 846 cases (99%). 615 (72.7%) samples were classified as IS-High (311 and 304 in 3m and 6m arm, respectively). No significant association between IS and patients’ gender, age, PS, BMI or primary tumour location was observed. However, a significant difference between IS-High (43.7%) and IS Low (57.1%) was observed in the proportion of high risk (T4 and/or N2) tumours (p=0.001). Patients with IS-High tumors had significantly longer 3y-DFS (79.4%, 95%CI: 75.9%-82.4%) compared to those with IS-Low tumors (65.0%, 95%CI: 58.3%-70.9%); adjusted hazard ratio (HR) 1.9 (95%CI: 1.46-2.46; p