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BACKGROUND AND OBJECTIVE: Palliative radiotherapy (RT) and systemic immuno- or targeted therapy both play significant roles in the treatment of advanced hepatocellular carcinoma (HCC). Concurrent application of these therapies is increasing, however, no guidelines exist regarding the combination of systemic therapy with RT. This narrative review summarises the existing literature reporting toxicity observed after concurrent treatment with RT and immuno- or targeted therapeutic agents commonly used in HCC. METHODS: The PubMed database was searched for studies published between 2011 and 2023 reporting toxicity data on patients treated concurrently with RT and targeted agents used in HCC. Due to the paucity of relevant literature in HCC, the inclusion criteria were expanded to include non-HCC cohorts treated with targeted therapies commonly used in advanced HCC. KEY CONTENT AND FINDINGS: Sixty-seven articles were included in this review. Twenty-two articles reported combined RT with sorafenib, one with regorafenib, 22 with bevacizumab, three with lenvatinib and 19 with immune checkpoint inhibitors. Significant findings include a high rate severe hepatotoxicity with combination RT and sorafenib, ranging from 0-19% with liver stereotactic body radiotherapy (SBRT) and 3-18% with conventionally fractionated liver RT. Severe gastrointestinal (GI) toxicities including perforation and ulceration were seen with combination bevacizumab and RT, ranging from 0-27% in the acute setting and 0-23% in the late setting. The safety profile of combination immune checkpoint blockade agents and RT was similar to that seen in monotherapy. CONCLUSIONS: Existing data suggests that combination RT and targeted therapy given the risk of severe adverse events including hepatotoxicity and GI toxicity. There is an urgent need for future studies specifically examining the impact of combination therapy in HCC patients to guide clinical decision-making in the evolving landscape of immune- and targete

Background: Use of neoadjuvant (NA) chemotherapy is recommended when pancreatic ductal adenocarcinoma (PDAC) is borderline resectable. Method: A retrospective analysis of consecutive patients with localized PDAC between January 2016 and March 2019 within the Australasian Pancreatic Cancer Registry (PURPLE, Pancreatic cancer: Understanding Routine Practice and Lifting End results) was performed. Clinicopathological characteristics, treatment, and outcome were analyzed. Overall survival (OS) comparison was performed using log-rank model and Kaplan–Meier analysis. Results: The PURPLE database included 754 cases with localised PDAC, including 148 (20%) cases with borderline resectable pancreatic cancer (BRPC). Of the 148 BRPC patients, 44 (30%) underwent immediate surgery, 80 (54%) received NA chemotherapy, and 24 (16%) were inoperable. The median age of NA therapy patients was 63 years and FOLFIRINOX (53%) was more often used as NA therapy than gemcitabine/nab-paclitaxel (31%). Patients who received FOLFIRINOX were younger than those who received gemcitabine/nab-paclitaxel (60 years vs. 67 years, p =.01). Surgery was performed in 54% (43 of 80) of BRPC patients receiving NA chemotherapy, with 53% (16 of 30) achieving R0 resections. BRPC patients undergoing surgery had a median OS of 30 months, and 38% (9 of 24) achieved R0 resection. NA chemotherapy patients had a median OS of 20 months, improving to 24 months versus 10 months for patients receiving FOLFIRINOX compared to gemcitabine/nab-paclitaxel (Hazard Ratio (HR).3, p <.0001). Conclusions: NA chemotherapy use in BRPC is increasing in Australia. One half of patients receiving NA chemotherapy proceed to curative resection, with 53% achieving R0 resections. Patients receiving Infusional 5-flurouracil, Irinotecan and Oxaliplatin (FOLIRINOX) had increased survival than gemcitabine/nab-paclitaxel. Treatment strategies are being explored in the MASTERPLAN and DYNAMIC-Pancreas trials.

Background: Enco + cetux (doublet) has been approved in the US, EU, and Japan for the treatment of BRAF V600E-mutant mCRC after progression on 1-2 prior regimens. In the BEACON CRC study (NCT02928224), median OS (95% CI) with the doublet was 9.3 months (8.0-11.3) vs 5.9 months (5.1-7.1) with cetux + irinotecan or FOLFIRI (control) in patients (pts) with BRAF V600E-mutant mCRC (HR 0.61 [95% CI: 0.5-0.8]). This post hoc analysis investigates OS by prior therapies to the doublet treatment in pts with BRAF V600E-mutant mCRC from the BEACON CRC study. Methods : OS of pts treated with the doublet or control were compared according to prior treatment with bevacizumab, oxaliplatin or FOLFOXIRI and duration of prior anticancer therapy (ACT). Results : Sixty-four per cent and 55% of pts in the doublet and control arm respectively received prior bevacizumab. Of pts who had one prior therapy, 95% and 88% received prior oxaliplatin and 20% and 14% received prior FOLFOXIRI, respectively. In the doublet arm, pts who had bevacizumab < 4 months before start of study treatment had a median OS of 8.3 months (95% CI: 6.2-11.2); those who had bevacizumab >=4 months prior had a median OS of 10.7 (95% CI: 7.5-17.7). Within each treatment arm, OS was similar regardless of prior treatment with oxaliplatin or FOLFOXIRI. The duration of prior ACT was similar across study arms, ranging from 5.6 to 5.8 months for the first line of ACT. Conclusions : In the BEACON CRC study, pts treated with the doublet for BRAF V600E-mutant mCRC demonstrated similar OS regardless of prior therapies or duration of prior therapy use. This exploratory post hoc analysis provides data that reflect the prior treatment landscape clinicians may face when deciding subsequent treatment regimens for pts with BRAF V600E-mutant mCRC.

Background: In the BEACON study, encorafenib + binimetinib + cetuximab (enco/bini/cetux; triplet) and enco + cetux (doublet) improved OS and ORR vs standard of care in previously treated BRAF V600E-mutant mCRC pts. Molecular profiling of tumours from this study was performed to identify molecular correlates of outcome. Methods : Baseline tumour samples were analysed by whole-exome sequencing (WES) and whole transcriptome sequencing (WTS). BRAF-mutant (BM) and consensus molecular subtypes (CMS) were determined and pathway activities evaluated with gene set variation analysis. Tumour response was evaluated for each subtype. Additional association and interaction analyses between molecular features and outcomes by treatments are ongoing and will be presented. Results : Baseline tumour samples were analysed by WES and/or WTS for 79.2% of pts. Of the 460 pts analysed by WTS (73.7% in the triplet arm, 66.4% in the doublet arm, 67.4% in the control arm), 84.6% were classified as CMS1 or CMS4. Overall 32.2% of pts were classified as BM1 and the majority (84.5%) of these were CMS4. Many of those classified as BM2 (67.8%) were CMS1 (64.7%). In the BM1 and CMS4 tumours, expression of inflammatory response and epithelial mesenchymal transition genes were elevated, and expression of cell cycle genes was reduced. Response rate in pts with CMS4 and/or BM1 tumors was higher in the triplet arm (CMS4: 33.3% [95% CI: 21.7-46.7]; BM1: 33.3% [95% CI: 21.4-47.1]) vs the doublet arm (CMS4: 19.2% [95% CI: 9.6-32.5]; BM1: 14.9% [95% CI: 6.2-28.3]). Conclusions : Molecular characteristics and biological properties observed in BRAF V600E-mutant mCRC suggest a subset of pts with specific molecular features may derive greater clinical benefit from triplet vs doublet therapy. These findings support further investigating the biological landscape in BRAF-mutant mCRC to enable potential hypotheses for pt selection to improve clinical outcome in future studies.

Gastrointestinal stromal tumours (GISTs) are the most common gastrointestinal tract mesenchymal tumours. Tyrosine kinase inhibitors (TKIs) have transformed the management of advanced GIST. Imatinib was the first TKI to gain approval as management for patients with advanced GIST, establishing a new standard of care. Since then, as a result of several trials including the GRID and INVICTUS studies, we now have five lines of approved targeted therapy, including imatinib, sunitinib, regorafenib, ripretinib and avapritinib for the treatment of unresectable, advanced GISTs. In this review, the Australasian Gastrointestinal Trials Group (AGITG) provide an overview of the key trials that have changed clinical practice, discuss the molecular drivers of GISTs, the importance of molecular testing and directing therapy according to molecular targets, as well as future strategies in the management of advanced GISTs.

BACKGROUND: We evaluated the time to progression (TTP) and survival outcomes of second-line therapy for metastatic colorectal cancer among adults aged 70 years and older compared with younger adults following progression on first-line clinical trials. METHODS: Associations between clinical and disease characteristics, time to initial progression, and rate of receipt of second-line therapy were evaluated. TTP and overall survival (OS) were compared between older and younger adults in first- and second-line trials by Cox regression, adjusting for age, sex, Eastern Cooperative Oncology Group Performance Status, number of metastatic sites and presence of metastasis in the lung, liver, or peritoneum. All statistical tests were 2-sided. RESULTS: Older adults comprised 16.4% of patients on first-line trials (870 total older adults aged >70 years; 4419 total younger adults aged ≤70 years, on first-line trials). Older adults and those with Eastern Cooperative Oncology Group Performance Status >0 were less likely to receive second-line therapy than younger adults. Odds of receiving second-line therapy decreased by 11% for each additional decade of life in multivariable analysis (odds ratio = 1.11, 95% confidence interval = 1.02 to 1.21, P = .01). Older and younger adults enrolled in second-line trials experienced similar median TTP and median OS (median TTP = 5.1 vs 5.2 months, respectively; median OS = 11.6 vs 12.4 months, respectively). CONCLUSIONS: Older adults were less likely to receive second-line therapy for metastatic colorectal cancer, though we did not observe a statistical difference in survival outcomes vs younger adults following second-line therapy. Further study should examine factors affecting decisions to treat older adults with second-line therapy. Inclusion of geriatric assessment may provide better criteria regarding the risks and benefits of second-line therapy.

BACKGROUND: Pancreatic cancer is a malignancy with one of the poorest prognoses amongst all cancers. Patients with unresectable tumours either receive palliative care or undergo various chemoradiotherapy regimens. Conventional techniques are often associated with acute gastrointestinal toxicities, as adjacent critical structures such as the duodenum ultimately limits delivered doses. Stereotactic body radiotherapy (SBRT) is an advanced radiation technique that delivers highly ablative radiation split into several fractions, with a steep dose fall-off outside target volumes. AIM: To discuss the latest data on SBRT and whether there is a role for magnetic resonance-guided techniques in multimodal management of locally advanced, unresectable pancreatic cancer. METHODS: We conducted a search on multiple large databases to collate the latest records on radiotherapy techniques used to treat pancreatic cancer. Out of 1229 total records retrieved from our search, 36 studies were included in this review. RESULTS: Studies indicate that SBRT is associated with improved clinical efficacy and toxicity profiles compared to conventional radiotherapy techniques. Further dose escalation to the tumour with SBRT is limited by the poor soft-tissue visualisation of computed tomography imaging during radiation planning and treatment delivery. Magnetic resonance-guided techniques have been introduced to improve imaging quality, enabling treatment plan adaptation and re-optimisation before delivering each fraction. CONCLUSION: Therefore, SBRT may lead to improved survival outcomes and safer toxicity profiles compared to conventional techniques, and the addition of magnetic resonance-guided techniques potentially allows dose escalation and conversion of unresectable tumours to operable cases.

Introduction: Pancreatic cancer remains a challenging malignancy due to the high proportion of patients diagnosed at advanced stages and the limited treatment options. This article discusses recent evidence in the management of both localized and advanced pancreatic cancer and offers an expert opinion on current best practice. Areas covered: For patients with localized disease, the evidence for adjuvant chemotherapy is discussed as well as emerging neoadjuvant approaches for resectable, borderline resectable, and locally advanced disease. Advances in metastatic disease are discussed including cytotoxic chemotherapy, targeted therapies, and the role of genomic testing to identify patients with molecular alterations. Reviewed literature included journal publications, abstracts presented at major international oncology meetings, and ongoing clinical trials databases. Expert opinion: Pancreatic cancer is a devastating diagnosis and despite recent advances has a very poor prognosis. Only a minority of patients, 20%, are diagnosed with potentially curable disease. The shifting paradigm toward neoadjuvant therapy may improve resectability and survival rates; however, robust evidence is required. Thus far, there has only been limited progress in advanced stage disease. Genomic testing may potentially identify more treatment targets although limited to small subgroups.Copyright © 2021 Informa UK Limited, trading as Taylor & Francis Group.

Background: BEACONCRC is a randomized, phase 3 study which evaluated the triplet of encorafenib (ENCO) + binimetinib (BINI) + cetuximab (CETUX) and the doublet of ENCO + CETUX vs. investigator's choice of irinotecan + CETUX or FOLFIRI + CETUX in patients (pts) with BRAFV600E metastatic colorectal cancer (mCRC) whose disease had progressed after 1-2 prior regimens in the metastatic setting. Primary endpoints were overall survival (OS) and objective response rate (ORR; by blinded central review) for triplet vs control. In a previous interim analysis, triplet and doublet improvedOS andORRversus standard of care. Here we report on an updated analysis. Method(s): Updated analysis includes 6 months of additional follow-up and response data for all randomized pts. The study is ongoing. Result(s): Patients received triplet (n = 224), doublet (n = 220), or control (n = 221). Median OS was 9.3 months (95% confidence interval [CI]:8.2, 10.8) for triplet and 5.9 months (95% CI:5.1-7.1) for control (hazard ratio [HR] (95% CI): 0.60 (0.47-0.75)). Median OS for doublet was 9.3 months (95% CI: 8.0-11.3) (HR vs control: 0.61 (0.48- 0.77). Confirmed ORR was 26.8% (95% CI: 21.1%-33.1%) for triplet, 19.5% (95% CI: 14.5%-25.4%) for doublet, and 1.8% (95% CI: 0.5%- 4.6%) for control. Retrospective subgroup analyses suggested some pts may benefit more from triplet than doublet therapy (Table). Both triplet and doublet showedimprovedOS compared to control in all subgroups. Adverse events were consistent with prior analysis, with grade >=3 adverse events in 65.8%, 57.4%, and 64.2% for triplet, doublet and control, respectively. Conclusion(s): The updated analysis of the BEACON CRC study confirmed that encorafenib + cetuximab with or without binimetinib improved OS and ORR in previously treated pts with BRAF V600E mCRC compared with standard chemotherapy.

BRAF V600E mutations are identified in <=15% of metastatic colorectal cancer (mCRC) patients and confer a poor prognosis. In patient's refractory to initial therapy, ORR to standard chemotherapy and biologic combinations are generally <10%, with median PFS and OS of ~2 and 4-6 months, respectively. The BEACON CRC Study (NCT02928224) was a multicentre, randomized, open-label, 3-arm, phase 3 study evaluating ENCO + CETUX +/- BINI (triplet or doublet combination) versus investigator's choice of Irinotecan or FOLFIRI + CETUX (control) in patients with BRAF V600E-mutant mCRC who had failed one or two prior regimens in the metastatic setting. Primary endpoints were OS and ORR (blinded central review) for the triplet versus control arm; secondary endpoints included OS for the doublet versus control arm, as well as PFS, duration of response and safety. A total of 665 patients were randomly assigned to receive: triplet combination (n= 224), doublet combination (n= 220) or control regimen (n= 221). Median OS was 9.0 months (95% CI, 8.0-11.4) for the triplet versus 5.4 months (95% CI, 4.8-6.6) for control regimens (HR: 0.52; 95% CI, 0.39-0.70; P < .0001). ConfirmedORR(blinded central review) was 26% (95% CI, 18-35%) for the triplet versus 2% (95% CI, <1% to 7%) for control (P < .0001). Median OS for the doublet was 8.4months (95% CI, 7.5-11.0) (HR vs control, 0.60; 95% CI, 0.45-0.79; P = .0003). Adverse events (AEs) were consistent with prior trials with each combination. AEs >=grade 3 occurred in 58%, 50% and 61% of patients in the triplet, doublet and control arms, respectively. ENCO + BINI + CETUX improved OS and ORR in patients with BRAF V600E-mutant mCRC compared with current standard of care chemotherapy and had a safety profile consistent with the known safety profile of each agent. This targeted therapy regimen should be a new standard of care for this patient population.

Background: Doublet chemotherapy in combination with a biologic agent has been a standard of care in patients with metastatic colorectal cancer for over a decade. The evidence for a "lighter" treatment approach is limited to mono-chemotherapy plus bevacizumab in the RAS unselected population. Anti-EGFR antibodies have activity as monotherapy or in combination with chemotherapy in RAS wildtype metastatic colorectal cancer; however their role in first-line treatment in combination with 5-fluorouracil monotherapy or when given alone has not been well studied. MONARCC aims to investigate this approach in an elderly population. Methods/design: MONARCC is a prospective, open-label, multicentre, non-comparative randomised phase II trial. Eligible patients aged >=70 with unresectable metastatic, untreated, RAS/BRAF wildtype metastatic colorectal cancer will be randomised 1:1 to receive panitumumab alone or panitumumab plus infusional 5-fluorouracil. RAS and BRAF analyses will be performed in local laboratories. Comprehensive Health Assessment and Limited Health Assessments will be performed at baseline and at 16 weeks, respectively, to assess frailty. The Patient Symptom Questionnaire and Overall Treatment Utility are to be undertaken at different timepoints to assess the impact of treatment-related toxicities and quality of life. Treatment will be delivered every 2 weeks until disease progression, unacceptable toxicity (as determined by treating clinician or patient), delay of treatment of more than 6 weeks, or withdrawal of consent. The primary end point is 6-month progression-free survival in both arms. Secondary end points include overall survival, time to treatment failure, objective tumour response rate as defined by RECIST v1.1 and safety (adverse events). Tertiary and correlative endpoints include the feasibility and utility of a comprehensive geriatric assessment, quality of life and biological substudies. Discussion(s): MONARCC investigates the activity and tolera

PURPOSE: The PETACC 6 trial investigates whether the addition of oxaliplatin to preoperative capecitabine-based chemoradiation and postoperative capecitabine improves disease-free survival (DFS) in locally advanced rectal cancer. METHODS: Between November 2008 and September 2011, patients with rectal adenocarcinoma within 12 cm from the anal verge, T3/4 and/or node positive, were randomly assigned to 5 weeks preoperative capecitabine-based chemoradiation (45-50.4 Gy) followed by six cycles of adjuvant capecitabine, both without (control arm, 1) or with (experimental arm, 2) oxaliplatin. The primary end point was improvement of 3-year DFS by oxaliplatin from 65% to 72% (hazard ratio [HR], 0.763). RESULTS: A total of 1,094 patients were randomly assigned (intention to treat), and 1,068 eligible patients started their allocated treatment (arm 1, 543; arm 2, 525), with completion of protocol treatment in 68% (arm 1) v 54% (arm 2). A higher rate of grade 3/4 adverse events was reported in the experimental arm (14.4% v 37.3% and 23.4% v 46.6% for neoadjuvant and adjuvant treatment, respectively). At a median follow-up of 68 months (interquartile range, 58-74 months), 157 and 156 DFS events were observed in arms 1 and 2, respectively (adjusted HR, 1.02; 95% CI, 0.82 to 1.28; P = .835). Three-year DFS rate was not different, with 76.5% (95% CI, 72.7% to 79.9%) in arm 1, which is higher than anticipated, and 75.8% (95% CI, 71.9% to 79.3%) in arm 2. The 7-year DFS and overall survival (OS) rates were not different as well, with DFS of 66.1% v 65.5% (HR, 1.02) and OS of 73.5% v 73.7% (HR, 1.19) in arms 1 and 2, respectively. Subgroup analyses revealed heterogeneity in treatment effect according to German versus non-German site location, without detectable confounding factors in multivariable analysis. CONCLUSION: The addition of oxaliplatin to preoperative capecitabine-based chemoradiation and postoperative adjuvant chemotherapy impairs tolerability and feasibility and does no

INTRODUCTION: Tumor hypoxia and angiogenesis are implicated in tumor growth and metastases, and anti-angiogenic therapies have an important role in treating patients with metastatic colorectal cancer. However, the prevalence of hypoxia has not been fully evaluated in colorectal liver metastases, and hypoxic response to anti-angiogenic therapy has not been clearly established. The aims of the study were to evaluate the changes seen on 18F-FMISO and 18F-FDG PET scans in patients treated with anti-angiogenic therapy, and to correlate these measures of hypoxia and metabolism with clinical outcomes, and blood biomarkers of angiogenesis. METHODS: Patients with metastatic colorectal carcinoma planned for treatment with bevacizumab and chemotherapy received routine staging investigations prior to any treatment, including a FDG PET scan. A FMISO PET scan was performed within 4 weeks of staging tests, with blood specimens collected at that time for serum VEGF and osteopontin measurement. Follow-up FDG and FMISO scans were performed after 1 cycle of treatment. Results were compared to response (RECIST), progression free survival (PFS), and overall survival (OS). RESULTS: A total of 15 patients were recruited into this prospective trial, of which 13 patients were evaluable for assessment of treatment follow-up. Baseline FDG uptake was higher than FMISO uptake, and there was a significant decrease in FDG uptake (SUVmax and TGV) but not FMISO uptake (SUVmax and TNR) after treatment. There was a positive correlation between FDG and FMISO SUVmax on both baseline and post-treatment PET scans. Blood biomarkers of serum VEGF and osteopontin were significantly correlated with the FDG and FMISO PET parameters. CONCLUSIONS: This study shows that hypoxia in metastatic colorectal cancer, assessed by FMISO PET, shows minor changes following initial treatment with anti-angiogenic therapy, but is associated with therapeutic response. FDG PET uptake changes (SUVmax, TLG) are also associated wi

BACKGROUND: SCOT was an international, randomized phase 3 trial of 3 months vs 6 months of adjuvant chemotherapy with oxaliplatin and a fluoropyrimidine in patients with colorectal cancer. We sought patients' preferences for 3 months vs 6 months of adjuvant chemotherapy in the SCOT trial. METHODS: SCOT participants from Australia and New Zealand completed a validated questionnaire (at 3 and 18 months) to elicit the minimum survival benefits judged necessary to make an extra 3 months of adjuvant chemotherapy worthwhile, based on their experience. Standardized hypothetical scenarios used the following baseline survivals (with 3 months of chemotherapy): life expectancies (LE) of 5 years and 15 years and 5-year survival rates (5YS) of 65% and 85%. RESULTS: Of the 160 participants, 82 were assigned 3 months adjuvant chemotherapy, and 78 were assigned 6 months. Adjuvant chemotherapy was FOLFOX in 121 (75.6%) and XELOX in 39 (24.4%). Preferences varied substantially and did not differ according to treatment group. The median survival benefits judged necessary to make the extra 3 months of chemotherapy worthwhile were an extra 3 years beyond a LE of 5 years; 3 years beyond a LE of 15 years; 15% beyond a 5YS of 65%; and 5% beyond a 5YS of 85%. Preferences were similar at 3 months and 18 months. Preferences were not predicted by participants' baseline characteristics. CONCLUSION: Preferences varied substantially, and the benefits many required to warrant an extra 3 months of adjuvant chemotherapy were larger than the benefits of an extra 3 months of chemotherapy calculated in the International Duration Evaluation of Adjuvant Chemotherapy (IDEA) meta-analysis.

BACKGROUND: Benchmarking international cancer survival differences is necessary to evaluate and improve healthcare systems. Our aim was to assess the potential regional differences in outcomes among patients with metastatic colorectal cancer (mCRC) participating in international randomized clinical trials (RCTs). DESIGN: Countries were grouped into 11 regions according to the World Health Organization and the EUROCARE model. Meta-analyses based on individual patient data were used to synthesize data across studies and regions and to conduct comparisons for outcomes in a two-stage random-effects model after adjusting for age, sex, performance status, and time period. We used mCRC patients enrolled in the first-line RCTs from the ARCAD database, which provided enrolling country information. There were 21,509 patients in 27 RCTs included across the 11 regions. RESULTS: Main outcomes were overall survival (OS) and progression-free survival (PFS). Compared with other regions, patients from the United Kingdom (UK) and Ireland were proportionaly over-represented, older, with higher performance status, more frequently male, and more commonly not treated with biological therapies. Cohorts from central Europe and the United States (USA) had significantly longer OS compared with those from UK and Ireland (p = 0.0034 and p < 0.001, respectively), with median difference of 3-4 months. The survival deficits in the UK and Ireland cohorts were, at most, 15% at 1 year. No evidence of a regional disparity was observed for PFS. Among those treated without biological therapies, patients from the UK and Ireland had shorter OS than central Europe patients (p < 0.001). CONCLUSIONS: Significant international disparities in the OS of cohorts of mCRC patients enrolled in RCTs were found. Survival of mCRC patients included in RCTs was consistently lower in the UK and Ireland regions than in central Europe, southern Europe, and the USA, potentially attributed to greater overall population repr

BACKGROUND: Doublet chemotherapy in combination with a biologic agent has been a standard of care in patients with metastatic colorectal cancer for over a decade. The evidence for a "lighter" treatment approach is limited to mono-chemotherapy plus bevacizumab in the RAS unselected population. Anti-EGFR antibodies have activity as monotherapy or in combination with chemotherapy in RAS wildtype metastatic colorectal cancer; however their role in first-line treatment in combination with 5-fluorouracil monotherapy or when given alone has not been well studied. MONARCC aims to investigate this approach in an elderly population. METHODS/DESIGN: MONARCC is a prospective, open-label, multicentre, non-comparative randomised phase II trial. Eligible patients aged ≥70 with unresectable metastatic, untreated, RAS/BRAF wildtype metastatic colorectal cancer will be randomised 1:1 to receive panitumumab alone or panitumumab plus infusional 5-fluorouracil. RAS and BRAF analyses will be performed in local laboratories. Comprehensive Health Assessment and Limited Health Assessments will be performed at baseline and at 16 weeks, respectively, to assess frailty. The Patient Symptom Questionnaire and Overall Treatment Utility are to be undertaken at different timepoints to assess the impact of treatment-related toxicities and quality of life. Treatment will be delivered every 2 weeks until disease progression, unacceptable toxicity (as determined by treating clinician or patient), delay of treatment of more than 6 weeks, or withdrawal of consent. The primary end point is 6-month progression-free survival in both arms. Secondary end points include overall survival, time to treatment failure, objective tumour response rate as defined by RECIST v1.1 and safety (adverse events). Tertiary and correlative endpoints include the feasibility and utility of a comprehensive geriatric assessment, quality of life and biological substudies. DISCUSSION: MONARCC investigates the activity and tolerabili