Background Neoadjuvant chemoradiation therapy is standard‐of‐care treatment for locally advanced rectal cancer (LARC). A pathological complete response (pCR) following chemoradiation therapy is an early indicator of treatment benefit and associated with excellent survival outcomes, with capecitabine largely replacing infusional 5‐fluorouracil as the choice in routine care of LARC. Aims To analyse the uptake of capecitabine usage over time, and on the back of clinical trial data demonstrating equivalence between fluoropyrimidines, confirm that efficacy is maintained in the real‐world setting. Methods We analysed data from a prospectively maintained colorectal cancer database at three Australian hospitals including patients diagnosed from January 2009 to December 2018. Pathological response was determined as either complete or incomplete and compared for patients receiving 5‐FU or capecitabine. Results A total of 657 patients was analysed, 498 receiving infusional 5‐FU and 159 capecitabine. Capecitabine use has markedly increased from approval in 2014 in Australia, now being used in more than 80% of patients. Patient characteristics were similar by treatment, including age, tumour location and pre‐treatment stage. pCR was reported in 22/159 (13.8%) of capecitabine‐treated patients and 118/380 (23.7%) that received 5‐FU (P ≤ 0.01). More capecitabine‐treated patients received post‐operative oxaliplatin (44.2% vs 6.3%, P < 0.01). Two‐year progression‐free survival was similar (84.9% vs 88.0%, P = 0.34). Conclusions Capecitabine is now the dominantly used neoadjuvant chemotherapy in LARC. Capecitabine use was associated with a lower rate of pCR versus infusional 5‐FU, a difference not explained by examined patient or tumour characteristics. Poor treatment compliance with oral therapy in the real‐world setting is one possible explanation.

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Pancreatic adenocarcinoma remains one of the most aggressive cancers with an ongoing dismal survival rate despite some recent advances in treatment options. This is largely due to the typically late presentation and limited effective therapeutic options in advanced disease. There are numerous circulating biomarkers that have potential clinical application as tumour markers, including circulating tumour DNA (ctDNA), circulating tumour cells (CTCs), cell-free RNA (cfRNA), exosomes and circulating tumour proteins. This review will focus on the development of ctDNA as a non-invasive liquid biopsy, with its high sensitivity and specificity having potential clinical applications in pancreatic cancer. These include a role in screening, prognostication via the detection of minimal residual disease, early detection of recurrence, and for patients with advanced disease; tumour genotyping and monitoring treatment response. Prospective randomised adjuvant clinical trials are currently underway, exploring the impact of ctDNA-guided adjuvant therapy decisions. In this review, we provide perspectives on the current literature and considerations of future directions.

Traditional cancer registries have often been siloed efforts, established by single groups with limited objectives. There is the potential for registry data to support a broad range of research, audit and education initiatives. Here, we describe the establishment of a series of comprehensive cancer registries across the spectrum of common solid cancers. The experience and learnings of each registry team as they develop, implement and then use collected data for a range of purposes, that informs the conduct and output of other registries in a virtuous cycle. Each registry is multi-site, multi-disciplinary and aims to collect data of maximal interest and value to a broad range of enquiry, which would be accessible to any researcher with a high-quality proposal. Lessons learnt include the need for careful and continuous curation of data fields, with regular database updates, and the need for a continued focus on data quality. The registry data as a standalone resource has supported numerous projects, but linkage with external datasets with patients in common has enhanced the audit and research potential. Multiple projects have linked registry data with matched tissue specimens to support prognostic and predictive biomarker studies, both validation and discovery. Registry-based biomarker trials have been successfully supported, generating novel and practice-changing data. Registry-based clinical trials, particularly randomised studies exploring the optimal use of available therapy options are now complementing the research conducted in traditional clinical trials. More recent projects supported by the registries include health economic studies, personalised patient education material, and increased consumer engagement, including consumer entered data.

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BackgroundTreatment with cetuximab provides a survival benefit for patients with RAS wild‐type metastatic colorectal cancer (mCRC). Practice‐defining cetuximab studies utilised weekly (q1w) administration. More convenient second weekly (q2w) administration is supported by pharmacokinetic data and a recent meta‐analysis, but large head‐to‐head studies have not been conducted. Therapeutic Goods Association (TGA) prescribing information states cetuximab be administered q1w for all indications.AimTo assess the real‐world use of q1w versus q2w cetuximab schedule and any difference in outcomes.MethodsWe analysed data from a prospective mCRC database at seven Melbourne hospitals from January 2010 to August 2019. Characteristics and outcomes for cetuximab‐treated patients were examined, comparing q1w versus q2w schedules. Progression‐free survival (PFS) and overall survival (OS) were the primary endpoints.ResultsOf 214 eligible patients, 103 (48%) received q1w and 111 (52%) received q2w cetuximab. Q2w cetuximab has been used in >70% of patients from 2015. Q2w was more commonly used in public patients (70% vs 13% in private, P < 0.001), in left‐sided primary tumours (83% vs 68%, P = 0.025) and in combination with chemotherapy (73% q2w vs 40% q1w, P < 0.001). Q2w treatment was less common in BRAFV600E mutated tumours (4% vs 13%, P = 0.001). PFS was similar across all lines of therapy, including when analyses were limited to a left‐sided primary and there was no difference in OS in multivariate analysis.ConclusionThis real‐world analysis shows q2w cetuximab has become the dominant method of administration, despite TGA guidance. Our outcome data adds to other data supporting the use of q2w cetuximab as the standard option. Consideration could be given to modifying current TGA advice.

71 Background: For patients with refractory metastatic colorectal cancer (mCRC) treatment with Trifluridine/Tipiracil, also known as TAS-102, improves overall survival. In Australia, TAS-102 was initially made available locally through patients self-funding, later via an industry sponsored Medicine Access Program (MAP) and then via the Pharmaceutical Benefits Scheme (PBS). This study aims to investigate the efficacy and safety of TAS-102 in real world Australian population. Methods: A retrospective analysis of prospectively collected data from the Treatment of Recurrent and Advanced Colorectal Cancer (TRACC) registry was undertaken. The characteristics and outcomes of patients receiving TAS-102 were assessed and compared to all TRACC patients and those enrolled in the registration study (RECOURSE). Results: Across 13 sites, 107 patients were treated with TAS-102 (non-PBS n = 27, PBS n = 80), The median number of patients per site was 7 (range: 1-17). The median age was 60 years (range: 31-83), compared to 67 for all TRACC patients and 63 for RECOURSE. Comparing registry TAS-102 and RECOURSE patients, 75% vs 100% were ECOG performance status 0-1, 74% vs 79% had initiated treatment more than 18 months from diagnosis of metastatic disease and 39% vs 49% were RAS wild type. Median time on treatment was 10.4 weeks (range: 1.7-32). Median clinician assessed progression-free survival was 3.3 compared to RECIST defined PFS of 2 months in RECOURSE study, while median overall survival was the same at 7.1 months. Two patients (2.3%) had febrile neutropenia and there were no treatment-related deaths in the real-world series, where TAS102 dose at treatment initiation was at clinician discretion. In the RECOURSE study there was a 4% febrile neutropenia rate and one treatment-related death. Conclusions: TRACC registry patients treated with TAS102 were younger than both TRACC patients overall and those from the RECOURSE trial. Less strict application of RECIST criteria and less frequent imaging may have contributed to an apparently longer PFS. However overall survival outcomes achieved with TAS102 in real world patients were comparable to findings from this pivotal trial with an acceptable rate of major adverse events.

e16072 Background: The KRASG12C mutation is present in 3% of colorectal cancer and is of particular interest given the recent development of specific targeting drugs. Previous data suggest KRAS (all) mutations may impact prognosis. Here we assess the clinical features and outcomes of real world patients with KRASG12C mutant metastatic colorectal cancer (mCRC) to explore any clinicopathologic associations and prognostic impact. Methods: Patients diagnosed with mCRC between January 2011 and December 2018 were included in this prospective mCRC registry. Patients with BRAF mutations, unknown or unspecified KRAS variants were excluded. Clinicopathologic features, treatment and overall survival (OS) were compared for RAS wildtype (RASWT) and KRASG12C mutant patients, and between KRASG12C and other (RASother) mutations. Results: Of 1308 patients analysed, 674 (52%) were RASmut, of whom 56 (8.3%) were KRASG12C. More patients with KRASG12C were female compared to RASother and RASWT (Table). No differences were observed in primary tumor location, number of metastatic sites and distribution of metastases. The proportion of patients undergoing metastasectomy was similar between KRASG12C and RASother, and KRASG12C and RASWT. There was no difference in the proportion of patients receiving systemic therapy. RASWT patients received more lines of therapy. Median OS was similar between KRASG12C, RASother, and RASWT: 31.7 vs 29.2 vs 31.8 months respectively (P = 0.545). Conclusions: KRASG12C mutations were observed in 4.3% of mCRC patients and in 8.3% of RAS mutant cases. Patients with KRASG12C have comparable clinical features to RASWT or RASother mCRC. Treatment and survival were also similar between groups. KRASG12C does not appear to be prognostic, but may be an important predictive biomarker as promising targeted therapies continue to be developed. [Table: see text]