Introducing Neoadjuvant Immunotherapy for Colorectal Cancer: Advancing the Frontier.

OBJECTIVE: To give surgeons a review of the current and future use of neoadjuvant immunotherapy in patients with localized colorectal cancer. BACKGROUND: Immunotherapy has revolutionized the standard of care in oncology and improved survival outcomes in several cancers. However, the applicability of immunotherapy is still an ongoing challenge. Some cancer types are less responsive to immunotherapy, and the heterogeneity in responses within cancer types is poorly understood. Clinical characteristics of the patient, the timing of immunotherapy in relation to surgery, diversities in the immune responses, clonal heterogeneity, different features of the tumor microenvironment, and genetic alterations are some factors among many that may influence the efficacy of immunotherapy. RESULTS: In this narrative review, we describe the major types of immunotherapy used to treat localized colorectal cancer. Furthermore, we discuss the prediction of response to immunotherapy in relation to biomarkers and radiological assessment. Finally, we consider the future perspectives of clinical implications and response patterns, as well as the potential and challenges of neoadjuvant immunotherapy in localized colorectal cancer. CONCLUSIONS: Establishing mismatch repair status at the time of diagnosis is central to the potential use of neoadjuvant immunotherapy, in particular immune checkpoint inhibitors, in localized colorectal cancer. To date, efficacy is primarily seen in patients with deficient mismatch repair status and POLE mutations, although a small group of patients with proficient mismatch repair does respond. In conclusion, neoadjuvant immunotherapy shows promising complete response rates, which may open a future avenue of an organ-sparing watch-and-wait approach for a group of patients.

Lenvatinib Plus Pembrolizumab Versus Standard of Care for Previously Treated Metastatic Colorectal Cancer: Final Analysis of the Randomized, Open-Label, Phase III LEAP-017 Study.

PURPOSE: Treatment options are limited for patients with previously treated metastatic colorectal cancer (mCRC). In the LEAP-017 study, we evaluate whether lenvatinib in combination with pembrolizumab improves outcomes compared with standard of care (SOC) in previously treated mismatch repair proficient or not microsatellite instability high (pMMR or not MSI-H) mCRC. METHODS: In this international, multicenter, randomized, controlled, open-label, phase III study, eligible patients age 18 years and older with unresectable, pMMR or not MSI-H mCRC, that had progressed on or after, or could not tolerate, standard treatment, were randomly assigned 1:1 to lenvatinib 20 mg orally once daily plus pembrolizumab 400 mg intravenously once every 6 weeks or investigator's choice of regorafenib or trifluridine/tipiracil (SOC). Randomization was stratified by presence or absence of liver metastases. The primary end point was overall survival (OS). LEAP-017 is registered at ClinicalTrials.gov (NCT04776148), and has completed recruitment. RESULTS: Between April 8, 2021, and December 21, 2021, 480 patients were randomly assigned to lenvatinib plus pembrolizumab (n = 241) or SOC (n = 239). At final analysis (median follow-up of 18.6 months [IQR, 3.9]), median OS with lenvatinib plus pembrolizumab versus SOC was 9.8 versus 9.3 months (hazard ratio [HR], 0.83 [95% CI, 0.68 to 1.02]; P = .0379; prespecified threshold P = .0214). Grade ≥3 treatment-related adverse events occurred in 58.4% (lenvatinib plus pembrolizumab) versus 42.1% (SOC) of patients. Two participants died due to treatment-related adverse events, both in the lenvatinib plus pembrolizumab arm. CONCLUSION: In patients with pMMR or not MSI-H mCRC that had progressed on previous therapy, there was no statistically significant improvement in OS after lenvatinib plus pembrolizumab treatment versus SOC. No new safety signals were observed.

The Association of Mismatch Repair Status with Microscopically Positive (R1) Margins in Stage III Colorectal Cancer: A Retrospective Cohort Study.

BACKGROUND: There is mounting evidence that microscopically positive (R1) margins in patients with colorectal cancer (CRC) may represent a surrogate for aggressive cancer biology rather than technical failure during surgery. However, whether detectable biological differences exist between CRC with R0 and R1 margins is unknown. We sought to investigate whether mismatch repair (MMR) status differs between Stage III CRC with R0 or R1 margins. METHODS: Patients treated for Stage III CRC from January 1, 2016 to December 31, 2019 were identified by using the Danish Colorectal Cancer Group database. Patients were stratified according to MMR status (proficient [pMMR] vs. deficient [dMMR]) and margin status. Outcomes of interest included the R1 rate according to MMR and overall survival. RESULTS: A total of 3636 patients were included, of whom 473 (13.0%) had dMMR colorectal cancers. Patients with dMMR cancers were more likely to be elderly, female, and have right-sided cancers. R1 margins were significantly more common in patients with dMMR cancers (20.5% vs. 15.2%, p < 0.001), with the greatest difference seen in the rate of R1 margins related to the primary tumour (8.9% vs. 4.7%) rather than to lymph node metastases (11.6% vs. 10.5%). This association was seen in both right- and left-sided cancers. On multivariable analyses, R1 margins, but not MMR status, were associated with poorer survival, alongside age, pN stage, perineural invasion, and extramural venous invasion. CONCLUSIONS: In patients with Stage III CRC, dMMR status is associated with increased risks of R1 margins following potentially curative surgery, supporting the use of neoadjuvant immunotherapy in this patient group.

Neoadjuvant treatment of colorectal cancer: comprehensive review.

BACKGROUND: Neoadjuvant therapy has an established role in the treatment of patients with colorectal cancer. However, its role continues to evolve due to both advances in the available treatment modalities, and refinements in the indications for neoadjuvant treatment and subsequent surgery. METHODS: A narrative review of the most recent relevant literature was conducted. RESULTS: Short-course radiotherapy and long-course chemoradiotherapy have an established role in improving local but not systemic disease control in patients with rectal cancer. Total neoadjuvant therapy offers advantages over short-course radiotherapy and long-course chemoradiotherapy, not only in terms of increased local response but also in reducing the risk of systemic relapses. Non-operative management is increasingly preferred to surgery in patients with rectal cancer and clinical complete responses but is still associated with some negative impacts on functional outcomes. Neoadjuvant chemotherapy may be of some benefit in patients with locally advanced colon cancer with proficient mismatch repair, although patient selection is a major challenge. Neoadjuvant immunotherapy in patients with deficient mismatch repair cancers in the colon or rectum is altering the treatment paradigm for these patients. CONCLUSION: Neoadjuvant treatments for patients with colon or rectal cancers continue to evolve, increasing the complexity of decision-making for patients and clinicians alike. This review describes the current guidance and most recent developments.

Temporal trends and regional variability in BRAF and KRAS genetic testing in Denmark (2010-2022): Implications for precision medicine.

OBJECTIVE: This study aims to evaluate the developments in the testing of Kirsten Rat Sarcoma viral oncogene homolog (KRAS) and v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) mutations across different cancer types and regions in Denmark from 2010 to 2022. STUDY DESIGN AND SETTING: Using comprehensive data from the Danish health registries, we linked molecular test results from the Danish Pathology Registry with cancer diagnoses from the Danish National Patient Registry between 2010 and 2022. We assessed the frequency and distribution of KRAS and BRAF mutations across all cancer types, years of testing, and the five Danish regions. RESULTS: The study included records of KRAS testing for 30 671 patients and BRAF testing for 30 860 patients. Most KRAS testing was performed in colorectal (78%) and lung cancer (18%), and BRAF testing in malignant melanoma (13%), colorectal cancer (67%), and lung cancer (12%). Testing rates and documentation mutational subtypes increased over time. Reporting of wildtype results varied between lung and colorectal cancer, with underreporting in lung cancer. Regional variations in testing and reporting were observed. CONCLUSION: Our study highlights substantial progress in KRAS and BRAF testing in Denmark from 2010 to 2022, evidenced by increased and more specific reporting of mutational test results, thereby improving the precision of cancer diagnosis and treatment. However, persistent regional variations and limited testing for cancer types beyond melanoma, colorectal, and lung cancer highlight the necessity for a nationwide assessment of the optimal testing approach.

TRIFLURIDINE/TIPIRACIL (FTD/TPI) with or without bevacizumab in previously treated patients with esophago-gastric adenocarcinoma, a randomised phase III trial.

Background: Trifluridine-tipiracil has shown a survival benefit compared with placebo in patients with chemorefractory metastatic esophago-gastric adenocarcinoma. We aimed to compare the efficacy of trifluridine-tipiracil plus bevacizumab vs trifluridine-tipiracil monotherapy in pre-treated patients with metastatic esophago-gastric adenocarcinoma. Methods: This investigator-initiated, open-label, randomized trial enrolled patients with metastatic esophago-gastric adenocarcinoma. The main inclusion criteria were patients with pre-treated metastatic esophago-gastric adenocarcinoma, and WHO performance status 0 or 1. Participants were randomly assigned (1:1) to receive oral trifluridine-tipiracil (35 mg/m2 twice daily on days 1-5 and 8-12 every 28 days) alone or combined with bevacizumab (5 mg/kg on days 1 and 15) until progression, unacceptable toxicity, or patient decision to withdraw. Randomisation was stratified by sex and treatment line. The primary endpoint was investigator-evaluated progression-free survival. All analyses were based on intention to treat. This trial is registered with EudraCT, 2018-004845-18. Findings: From Oct 1, 2019, to Sept 30, 2021, 103 patients were enrolled and randomly assigned to trifluridine-tipiracil (n = 53) or trifluridine-tipiracil plus bevacizumab (n = 50). The clinical cut-off date was March 1st, 2023, after a median follow-up of 36.6 months. Median progression-free survival was 3.1 months (95% CI 2.0-4.3) in the trifluridine-tipiracil group vs 3.9 months (3.0-6.3) in the trifluridine-tipiracil plus bevacizumab group (hazard ratio 0.68, 95% CI 0.46-1.02; p = 0.058). The most frequent grade 3 or worse adverse event was neutropenia, observed in 26 (49%) patients in the trifluridine-tipiracil group vs 23 patients (46%) in the trifluridine-tipiracil plus bevacizumab group. At least one hospitalization was observed in 21 patients (40%) in the trifluridine-tipiracil group and 22 patients (44%) in the trifluridine-tipiracil plus bevacizumab group. No deaths were deemed treatment related. Interpretation: In patients with pre-treated metastatic esophago-gastric cancer, trifluridine-tipiracil plus bevacizumab, compared to trifluridine-tipiracil monotherapy, did not significantly prolong progression-free survival. The combination of trifluridine-tipiracil with bevacizumab was well tolerated without increase in severe neutropenia and no new safety signals. Funding: Servier, Roche.

The path to cancer diagnosis for the elderly.

Older cancer patients are more often than younger diagnosed via an unplanned hospital admission which may negatively influence the prognosis. An increasing number of cancers is expected due to ageing of populations, and these phenomena are likely to result in an increase in older cancer patients with multiple complications, extended hospital stays, and reduced quality of life and survival. In this review, we present recent data about routes to cancer diagnosis for older vs younger patients to emphasize that diagnostic pathways need improvements to avoid an increase in unplanned hospital admissions due to cancer.

The role of immunotherapy in the treatment of colorectal cancer.

In Denmark, around 4,500 people are diagnosed with colorectal cancer (CRC) annually. This review investigates that while the efficacy of immunotherapy in CRC is still being studied, immunotherapy is currently only indicated in the treatment of mismatch-repair deficient (dMMR) metastatic CRC, which accounts for 10-15% of patients. Recent studies indicate high rates of pathologic response in dMMR CRC treated with pre-operative immunotherapy while large-scale studies on novel immunotherapy combinations are ongoing.

Impact of adjuvant chemotherapy on long-term overall survival in patients with high-risk stage II colon cancer: a nationwide cohort study.

BACKGROUND: This study aimed to investigate the impact of adjuvant chemotherapy on long-term survival in unselected patients with high-risk stage II colon cancer including an analysis of each high-risk feature. MATERIALS AND METHODS: Data from the Danish Colorectal Cancer Group, the National Patient Registry and the Danish Pathology Registry from 2014 to 2018 were merged. Patients surviving > 90 days were included. High-risk features were defined as emergency presentation, including self-expanding metal stents (SEMS)/loop-ostomy as a bridge to resection, grade B or C anastomotic leakage, pT4 tumors, lymph node yield < 12 or signet cell carcinoma. Eligibility criteria for chemotherapy were age < 75 years, proficient MMR gene expression, and performance status ≤ 2. The primary outcome was 5-year overall survival. Secondary outcomes included the proportion of eligible patients allocated for adjuvant chemotherapy and the time to first administration. RESULTS: In total 939 of 3937 patients with stage II colon cancer had high-risk features, of whom 408 were eligible for chemotherapy. 201 (49.3%) patients received adjuvant chemotherapy, with a median time to first administration of 35 days after surgery. The crude 5-year overall survival was 84.9% in patients receiving adjuvant chemotherapy compared with 66.3% in patients not receiving chemotherapy, p < 0.001. This association corresponded to an absolute risk difference of 14%. CONCLUSION: 5-year overall survival was significantly higher in patients with high-risk stage II colon cancer treated with adjuvant chemotherapy compared with no chemotherapy. Adjuvant treatment was given to less than half of the patients who were eligible for it.

Evaluating the efficacy and safety of neoadjuvant pembrolizumab in patients with stage I-III MMR-deficient colon cancer: a national, multicentre, prospective, single-arm, phase II study protocol.

INTRODUCTION: Within the last two decades, major advances have been made in the surgical approach for patients with colorectal cancer. However, to this day we face considerable challenges in reducing surgery-related complications and improving long-term oncological outcomes. Unprecedented response rates have been achieved in studies investigating immunotherapy in patients with mismatch repair deficient (dMMR) colorectal cancer. This has raised the question of whether neoadjuvant immunotherapy may change the standard of care for localised dMMR colon cancer and pave the way for organ-sparing treatment. METHODS AND ANALYSIS: This is an investigator-initiated, multicentre, prospective, single-arm, phase II study in patients with stage I-III dMMR colon cancer scheduled for intended curative surgery. Eighty-five patients will be treated with one dose of pembrolizumab (4 mg/kg) and within 5 weeks will undergo a re-evaluation with an endoscopy and a CT scan-to assess tumour response-before standard resection of the tumour. The primary endpoint is the number of patients with pathological complete response, and secondary endpoints include safety (number and severity of adverse events) and postoperative surgical complications. In addition, we aspire to identify predictive biomarkers that can point out patients that achieve pathological complete response. ETHICS AND DISSEMINATION: The Regional Committee for Health Research and Ethics and the Danish Medicines Agency have approved this study. The study will be performed according to the Helsinki II declaration. Written informed consent will be obtained from all participants. The results of the study will be submitted to peer-reviewed journals for publication and presented at international congresses. TRIAL REGISTRATION NUMBER: NCT05662527.

Therapy with pembrolizumab in treatment-naïve patients with nonmetastatic, mismatch repair deficient colorectal cancer.

Therapy with immune checkpoint inhibitors (ICI) is effective in patients with metastatic mismatch-repair deficient (dMMR) colorectal cancer (CRC); however, data on treatment with neoadjuvant ICI in patients with locally advanced CRC are limited. From March 2019 to June 2020, five Danish oncological centers treated 10 patients with a treatment-naïve dMMR CRC with preoperative pembrolizumab, 9 with a nonmetastatic, unresectable colon cancer and 1 with a locally advanced rectum cancer. All 10 patients were evaluated regularly at a multidisciplinary team (MDT) meeting, and they all had a radical resection after a median of 8 cycles (range 2-13) of pembrolizumab. A microscopic evaluation of the resected tumors revealed no remaining tumor cells in five patients, while five still had tumor cells present. The patients were given no additional therapy. No recurrences were reported after a median follow-up of 26 months (range 23-38.5 months). Biopsies from Danish patients with CRC are routinely screened for dMMR proteins. In 2017, data from the Danish Colorectal Cancer Group showed that 19% (565/3000) of the patients with colon cancer and 1.5% (19/1279) of those with rectum cancer had an dMMR tumor. Among the patients with MMR determination, 26% (99/384) patients had a T4 dMMR colon cancer; thus, the 10 patients treated with neoadjuvant pembrolizumab comprised about 9% of the patients with a T4 dMMR colon cancer (9/99) and 5% of patients with dMMR rectal cancer (1/19). Therapy with pembrolizumab was feasible and effective. Larger prospective trials are needed to confirm our findings.

Prognostic value of baseline functional status measures and geriatric screening in vulnerable older patients with metastatic colorectal cancer receiving palliative chemotherapy - The randomized NORDIC9-study.

INTRODUCTION: Appropriate patient selection based on functional status is crucial when considering older adults for palliative chemotherapy. This pre-planned analysis of the randomized NORDIC9-study explored the prognostic value of four functional status measures regarding progression-free survival (PFS) and overall survival (OS) in vulnerable older patients with metastatic colorectal cancer (mCRC) receiving first-line palliative chemotherapy. MATERIALS AND METHODS: Patients ≥70 years of age with mCRC not candidates for standard full-dose combination chemotherapy were randomized to receive full-dose S1 or reduced-dose S1 + oxaliplatin. At baseline, functional status was assessed using ECOG performance status (ECOG PS), frailty phenotype, Geriatric 8 (G8), and Vulnerable Elderly Survey-13 (VES-13). Multivariable regression models were applied and C-statistics were estimated. RESULTS: In total, 160 patients with a median age of 78 years (IQR: 76-81) were included. While in univariate analyses, ECOG PS, frailty phenotype, and VES-13 were statistically significantly associated with differences in OS between subgroups, G8 was not (HR = 1.55, 95%CI: 0.99-2.41, p = 0.050). In multivariable analyses adjusted for age, sex, body mass index, and treatment allocation, we found significant differences between subgroups for all applied tools and with C-statistics in the moderate range for ECOG PS and VES-13. Concerning PFS, statistically significant differences were observed between subgroups of ECOG PS, G8, and VES-13 both in uni- and multivariable analyses, but not for frailty phenotype. DISCUSSION: In this Nordic cohort of vulnerable older patients with mCRC, baseline ECOG PS, frailty phenotype, G8, and VES-13 showed prognostic value regarding overall survival, and moderate predictive value of models based on ECOG PS and VES-13 was demonstrated.

A phase II study of daily encorafenib in combination with biweekly cetuximab in patients with BRAF V600E mutated metastatic colorectal cancer: the NEW BEACON study.

BACKGROUND: Patients with BRAF V600E mutated metastatic colorectal cancer (mCRC) have a poor prognosis. The introduction of BRAF targeted therapy with encorafenib and weekly administered cetuximab have shown improved survival with a median progression free survival (PFS) of 4.3 months. However, a regimen with cetuximab given every second week may have comparable efficacy and is more convenient for patients. While BRAF targeted therapy is a new standard therapy in pre-treated patients with BRAF V600E mutated mCRC, resistance invariably occurs and is an emerging challenge. The aim of this study is to investigate the efficacy and tolerability of cetuximab given every second week in combination with daily encorafenib and to explore the correlation between markers of resistance and outcome. METHODS: The study is an open label, single arm, phase II study, investigating the efficacy and tolerability of cetuximab given every second week in combination with encorafenib in patients with BRAF V600E mutated mCRC. Furthermore, we will be investigating mechanisms of response and resistance against BRAF targeted therapy though comprehensive genomic profiling on tumor tissue and blood for circulating tumor DNA analysis. A total of 53 patients (19 + 34 in two steps) will be included according to Simon's optimal two stage design. The primary end point of the study is 2 months PFS rate. DISCUSSION: By combining BRAF inhibitor with cetuximab given every second week we can halve the number of visits in the hospital compared to the currently approved regimen with weekly cetuximab. This seems particularly relevant in a group of patients with a median overall survival of 9.3 months. Resistance after initial response to targeted therapy can be either adaptive (e.g., epigenetic, or transcriptomic alterations) or acquired (selective genetic alterations - e.g., activating de novo mutations) resistance. It is of great importance to untangle these complex mechanisms of resistance in patients with BRAF V600E mutated mCRC to improve treatment strategies in the future potentially even further. TRIAL REGISTRATION: EU Clinical Trial Register, Eudract no. 2020-003283-10 . Registered on 11 November 2020.

Extensive genomic analysis in patients with KRAS-mutated solid tumors shows high frequencies of concurrent alterations and potential targets but has limited clinical impact.

BACKGROUND: This study aimed to investigate the distribution and frequency of concurrent alterations in different cancers across KRAS subtypes and in different KRAS subtypes across cancers, and to identify potentially actionable targets and patients who received targeted treatment matched to their genomic profile (GP). MATERIALS AND METHODS: In this descriptive and single-center study, we included 188 patients with solid tumors harboring KRAS mutations in codon 12, 13, 61, 117, or 146, referred to the Phase 1 Unit, Rigshospitalet, Copenhagen, Denmark from mid-2016 to 2020. Genomic co-alterations were detected with whole-exome sequencing, RNA sequencing, SNP array, and mRNA expression array on fresh biopsies. The study is part of the Copenhagen Prospective Personalized Oncology study (NCT02290522). RESULTS: The majority of patients had colorectal cancer (60.1%), non-small cell lung cancer (11.2%), or pancreatic cancer (10.6%). Most tumors were KRAS-mutated in codon 12 or 13 (93.7%) including G12D (27.1%), G12V (26.6%), G12C (11.7%), and G13D (11.2%). A total of 175 different co-alterations were found, most frequently pathogenic APC and TP53 mutations (55.9% and 46.4%, respectively) and high expression of CEACAM5 (73.4%). Different cancers and KRAS subtypes showed different patterns of co-alterations, and 157 tumors (83.5%) had potentially actionable targets with varying evidence of targetability (assessed using ESMO Scale for Clinical Actionability of molecular Targets). Of the 188 patients included in the study, 15 (7.4%) received treatment matched to their GP (e.g., immunotherapy and synthetic lethality drugs), of whom one had objective partial response according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. CONCLUSION: Performing extensive genomic analysis in patients with known KRAS-mutated solid tumors may contribute with information to the genomic landscape of cancers and identify targets for immunotherapy or synthetic lethality drugs, but currently appears to have overall limited clinical impact, as few patients received targeted therapy matched to their GP.

The Prognostic Value of Pre-Treatment Circulating Biomarkers of Systemic Inflammation (CRP, dNLR, YKL-40, and IL-6) in Vulnerable Older Patients with Metastatic Colorectal Cancer Receiving Palliative Chemotherapy-The Randomized NORDIC9-Study.

Appropriate patient selection for palliative chemotherapy is crucial in patients with metastatic colorectal cancer (mCRC). We investigated the prognostic value of C-reactive protein (CRP), derived neutrophil-to-lymphocyte ratio (dNLR), Interleukin (IL)-6, and YKL-40 on progression-free survival (PFS) and overall survival (OS) in the NORDIC9 cohort. The randomized NORDIC9-study included patients ≥70 years with mCRC not candidates for standard full-dose combination chemotherapy. Participants received either full-dose S1 (Teysuno) or a dose-reduced S1 plus oxaliplatin. Blood samples were collected at baseline and biomarkers were dichotomized according to standard cut-offs. Multivariable analyses adjusted for age, sex, ECOG performance status, and treatment allocation; furthermore, C-statistics were estimated. In total, 160 patients with a median age of 78 years (IQR: 76−81) were included between 2015 and 2017. All investigated biomarkers were significantly elevated in patients with either weight loss, ≥3 metastatic sites, or primary tumor in situ. In multivariable analyses, all markers showed significant association with OS; the highest HR was observed for CRP (HR = 3.40, 95%CI: 2.20−5.26, p < 0.001). Regarding PFS, statistically significant differences were found for CRP and IL-6, but not for dNLR and YKL-40. Applying C-statistics, CRP indicated a good prognostic model for OS (AUC = 0.72, 95%CI: 0.67−0.76). CRP is an easily available biomarker, which may support therapeutic decision-making in vulnerable older patients with mCRC.

ctDNA for Risk of Recurrence Assessment in Patients Treated with Neoadjuvant Treatment: A Systematic Review and Meta-analysis.

BACKGROUND: We wanted to investigate the association between circulating tumor DNA (ctDNA) detection at baseline, during and after neoadjuvant treatment, after surgery, and recurrence, in patients with nonmetastatic cancer. PATIENTS AND METHODS: In this systematic review and meta-analysis, we included studies that investigated patients undergoing neoadjuvant treatment for nonmetastatic cancer and provided recurrence indices stratified for ctDNA status at the following timepoints: baseline, during treatment, posttreatment, and postsurgery. Study quality was reported with the Newcastle-Ottawa scale, REMARK checklist, and GRADE approach. PubMed, Embase, Cochrane Library, and Web of Science were our data sources (inception to 3 June 2021). The main outcome was risk of recurrence. RESULTS: We identified ten studies including 727 patients with rectal, breast, gastric, and bladder cancer. All studies reported posttreatment ctDNA analysis, while seven, four, and six reported baseline, during treatment, and postsurgery ctDNA analysis, respectively. ctDNA detection was associated to recurrence across all timepoints [baseline: risk ratio (RR) 2.86, 95% confidence interval (CI) 1.33-6.14, during treatment: RR 3.81, 95% CI 2.09-6.92, posttreatment: RR 4.29, 95% CI 2.79-6.60, postsurgery: RR 8.03, 95% CI 3.16-20.43]. Heterogeneity was low to moderate. CONCLUSIONS: This meta-analysis of observational studies found that ctDNA detection in patients undergoing neoadjuvant treatment for nonmetastatic cancer was associated with recurrence. A stronger association was evident in posttreatment and postsurgery timepoints. However, some studies reported low negative predictive value (NPV) of pathological complete response, showing that ctDNA-detection-guided escalation and de-escalation studies following neoadjuvant treatment regimens are needed before its role as a treatment guidance can be affirmed.

DPYD genotyping and dihydropyrimidine dehydrogenase (DPD) phenotyping in clinical oncology. A clinically focused minireview.

BACKGROUND: In clinical oncology, systemic 5-fluorouracil (5-FU) and its oral pro-drugs are used to treat a broad group of solid tumours. Patients with dihydropyrimidine dehydrogenase (DPD) enzyme deficiency are at elevated risk of toxicity if treated with standard doses of 5-FU. DPYD genotyping and measurements of plasma uracil concentration (DPD phenotyping) can be applied as tests for DPD deficiency. In April 2020, the European Medicines Agency recommended pre-treatment DPD testing to reduce the risk of 5-FU-related toxicity. OBJECTIVES: The objective of this study is to present the current evidence for DPD testing in routine oncological practice. METHODS: Two systematic literature searches were performed following the PRISMA guidelines. We identified studies examining the possible benefit of DPYD genotyping or DPD phenotyping on the toxicity risk. FINDINGS: Nine and 12 studies met the criteria for using DPYD genotyping and DPD phenotyping, respectively. CONCLUSIONS: The evidence supporting either DPYD genotyping or DPD phenotyping as pre-treatment tests to reduce 5-FU toxicity is poor. Further evidence is still needed to fully understand and guide clinicians to dose by DPD activity.