Circulating DNA and frequency of colorectal cancer brain metastases in a presumed high-risk group.

This explorative prospective observational pilot study investigated if suggested risk factors, rectal cancer and lung metastases, could add to a relevant detection rate of asymptomatic brain metastases (BM) from colorectal cancer (CRC). Secondary, prognostic biological aspects were investigated by translational analysis of plasma samples. The study enrolled patients with rectal cancer and lung metastases. At inclusion, patients underwent a standard MRI scan of the brain. Cell-free DNA (cfDNA) level was measured by a direct fluorescence assay (DFA), and circulating tumor DNA (ctDNA) by ddPCR. BM was detected in one of twenty-nine included patients. Patients had higher cfDNA levels than healthy subjects (p < 0.01). Patients with the primary tumor in situ had higher cfDNA levels than those with resected primary tumor (p < 0.01). Patients with liver involvement had higher cfDNA levels (p = 0.12) and circulating tumor DNA levels (p = 0.01) than those without liver involvement. In conclusion, the modest incidence of BM does not justify routine MRI of the brain in this selected population. cfDNA by DFA could be a valuable tool when planning treatment and follow-up for CRC patients. Future studies should focus on identifying further characteristics and biomarkers associated with a high risk of BM, enhancing the possibility for early intervention.

ctDNA-guided adjuvant treatment after radical-intent treatment of metastatic spread from colorectal cancer-the first interim results from the OPTIMISE study.

BACKGROUND: Patients with detectable ctDNA after radical-intent treatment of metastatic spread from colorectal cancer (mCRC) have a very high risk of recurrence, which may be prevented with intensified adjuvant chemotherapy (aCTh). In the OPTIMISE study, we investigate ctDNA-guided aCTh after radical-intent treatment of mCRC. Here we present results from the preplanned interim analysis. MATERIAL AND METHODS: The study is an open-label 1:1 randomized clinical trial comparing ctDNA-guided aCTh against standard of care (SOC), with a run-in phase investigating feasibility measures. Key inclusion criteria; radical-intent treatment for mCRC and clinically eligible for triple-agent chemotherapy. Patients underwent a PET-CT scan before randomization. ctDNA analyses of plasma samples were done by ddPCR, detecting CRC-specific mutations and methylation of the NPY gene. In the ctDNA-guided arm, ctDNA positivity led to an escalation strategy with triple-agent chemotherapy, and conversely ctDNA negativity led to a de-escalation strategy by shared-decision making. Patients randomized to the standard arm were treated according to SOC. Feasibility measures for the run-in phase were; the inclusion of 30 patients over 12 months in two Danish hospitals, compliance with randomization >80%, rate of PET-CT-positive findings <20%, and eligibility for triple-agent chemotherapy >80%. RESULTS: Thirty-two patients were included. The rate of PET-CT-positive cases was 22% (n = 7/32). Ninety-seven percent of the patients were randomized. Fourteen patients were randomly assigned to SOC and sixteen to ctDNA-guided adjuvant treatment and follow-up. All analyses of baseline plasma samples in the ctDNA-guided arm passed the quality control, and 19% were ctDNA positive. The median time to result was three working days. All ctDNA-positive patients were eligible for triple-agent chemotherapy. CONCLUSION: The study was proven to be feasible and continues in the planned large-scale phase II trial. Results from the OPTIMISE study will potentially optimize the adjuvant treatment of patients undergoing radical-intent treatment of mCRC, thereby improving survival and reducing chemotherapy-related toxicity.

Risk factors and outcome following salvage surgery for squamous cell carcinoma of the anus.

BACKGROUND: Chemoradiotherapy is the primary treatment for anal cancer. 15-33% of patients will have persistent or recurrent disease after treatment requiring salvage surgery. Relapse after surgery, postoperative complications, and mortality as well as possible risk factors are not fully understood due to the rareness of the disease. The aim of the study was to report outcomes after salvage surgery as well as evaluate risk factors for postoperative complications, cancer relapse and survival. METHODS: Data were retrospectively collected from electronical patients charts and pathology reports from all patients undergoing salvage surgery from July 1st, 2011 to July 1st, 2021 at the Department of Surgery, Aarhus University Hospital, Denmark. RESULTS: A total of 98 patients were included in the study. The 5-year overall survival was 61.8%. Relapse after surgery occurred in 36.7% of patients and was significantly associated with R1-resection (HR = 4.4) and preoperative nodal metastases (HR = 4.5). Negative prognostic factors for survival were found to be R1-resection (HR = 3.2), preoperative nodal metastases (HR = 2.9), and male gender (HR = 0.5). There was no association found between complications and survival (HR 1.2). None of the possible risk factors were associated with major postoperative complications. CONCLUSIONS: An acceptable overall survival after surgery was found. Survival and relapse-free survival was negatively associated with R1 resections and positive preoperative lymph nodes. Complications did not influence long-term survival.

The Importance of Feasibility Assessment in the Design of ctDNA Guided Trials - Results From the OPTIPAL II Study.

INTRODUCTION: Both quantitative and molecular changes in ctDNA can hold important information when treating metastatic colorectal cancer (mCRC), but its clinical utility is yet to be established. Before conducting a large-scale randomized trial, it is essential to test feasibility. This study investigates whether ctDNA is feasible for detecting patients who will benefit from treatment with epidermal growth factor receptor inhibitors and the prognostic value of circulating tumor DNA (ctDNA) response. MATERIALS AND METHODS: Patients with mCRC, who were considered for systemic palliative treatment and were eligible for ctDNA analysis. Mutational testing on cell-free DNA (cfDNA) was done by ddPCR. ctDNA response from baseline to the third treatment cycle was evaluated in patients with detectable ctDNA at baseline. ctDNA maximum response was defined as undetectable ctDNA at the third treatment cycle, ctDNA partial response as any decrease in the ctDNA level, and ctDNA progression as any increase in the ctDNA level. RESULTS: Forty-nine patients were included. The time to test results for mutational testing on cfDNA was significantly shorter than on tumor tissue (p < .001). Progression-free survival were 11.2 months (reference group), 7.5 months (HR = 10.7, p= .02), and 4.6 months (HR = 11.4, p= .02) in patients with ctDNA maximum response, partial response, and progression, respectively. Overall survival was 31.2 months (reference group), 15.2 months (HR = 4.1, p= .03), and 9.0 months (HR = 2.6, p= .03) in patients with ctDNA maximum response, partial response, and progression, respectively. CONCLUSION: Pretreatment mutational testing on cfDNA in daily clinic is feasible and can be applied in randomized clinical trials evaluating the clinical utility of ctDNA. Early dynamics in ctDNA during systemic treatment hold prognostic value.

Nordic anal cancer (NOAC) group consensus guidelines for risk-adapted delineation of the elective clinical target volume in anal cancer.

Background: To date, anal cancer patients are treated with radiotherapy to similar volumes despite a marked difference in risk profile based on tumor location and stage. A more individualized approach to delineation of the elective clinical target volume (CTVe) could potentially provide better oncological outcomes as well as improved quality of life. The aim of the present work was to establish Nordic Anal Cancer (NOAC) group guidelines for delineation of the CTVe in anal cancer.Methods: First, 12 radiation oncologists reviewed the literature in one of the following four areas: (1) previous delineation guidelines; (2) patterns of recurrence; (3) anatomical studies; (4) common iliac and para-aortic recurrences and delineation guidelines. Second, areas of controversy were identified and discussed with the aim of reaching consensus.Results: We present consensus-based recommendations for CTVe delineation in anal cancer regarding (a) which regions to include, and (b) how the regions should be delineated. Some of our recommendations deviate from current international guidelines. For instance, the posterolateral part of the inguinal region is excluded, decreasing the volume of irradiated normal tissue. For the external iliac region and the cranial border of the CTVe, we agreed on specifying two different recommendations, both considered acceptable. One of these recommendations is novel and risk-adapted; the external iliac region is omitted for low-risk patients, and several different cranial borders are used depending on the individual level of risk.Conclusion: We present NOAC consensus guidelines for delineation of the CTVe in anal cancer, including a risk-adapted strategy.

Circulating tumor DNA: Response Evaluation Criteria in Solid Tumors - can we RECIST? Focus on colorectal cancer.

Interest in the measurement of circulating tumor DNA (ctDNA) in colorectal cancer (CRC) has increased during the past decade. The analysis of quantitative ctDNA changes as a general response evaluation criterion during systemic treatment is a scientific approach with high clinical potential, and results can be transferred to a pan-cancer concept if relevantly investigated. The purpose of this overview is to discuss the current evidence for ctDNA as a marker of response in metastatic CRC (mCRC) and to propose criteria for definitions of response to systemic therapies applicable in prospective clinical trials. We discuss the literature, which supports a new definition of ctDNA Response Evaluation Criteria in Solid Tumors. Finally, we discuss the challenges in preparations of the optimal trial design to establish the true clinical utility of ctDNA.

Estimated dose to site of loco-regional recurrence after radiotherapy in anal cancer using point of origin methods.

Background and purpose: Loco-regional recurrence (LRR) dominates the failure pattern after curative radiotherapy in anal cancer. The aim of this study was to estimate dose of LRRs in anal cancer using a point of origin-based method. Method and materials: Of 321 patients with squamous cell carcinoma of the anus, 31 patients with LRR (29 local recurrences and 5 regional lymph node recurrences) were available for analysis. The recurrence volumes were delineated on recurrence magnetic resonance imaging (rMRI). Rigid and subsequent deformable co-registration of planning computerised tomography scans and rMRI were performed. Point of origin was estimated as the centre of mass (COM) and an observer-based point of origin (obs-PO). Doses to COM and obs-PO, as well as the full recurrence volume, were estimated and the relation to target volumes was extracted. Results: The median minimum dose to COM was 63.8 Gy (range 32.5-65.1 Gy) and 63.7 Gy (range 35.5-65.2 Gy) to obs-PO of local recurrences. COM was included in the high dose volume (64 Gy) in 86 % of cases, and obs-PO was included in 75 % of cases. There was no difference in minimum dose to COM and obs-PO, and the median distance between the two points was 3.3 mm (range 0.6-19.8 mm). No recurrences occurred in primarily boosted lymph nodes. Conclusion: The majority of LLRs were located within the high dose volume indicating radioresistance as the primary cause of recurrence in anal cancer. No difference between the use of COM and obs-PO was evident.

ctDNA-Response evaluation criteria in solid tumors - a new measure in medical oncology.

In the metastatic setting, most decisions during systemic palliative therapies are based on the imaging-based Response Evaluation Criteria in Solid Tumors (RECIST), which is, however, known to be a suboptimal surrogate marker for the clinical outcome overall survival. Over the past decade, research has brought focus to the potential of circulating tumour DNA in cancer. However, at present, there is no generally accepted classification of quantitative changes during the treatment course, and prospective investigations can therefore not be validated. We here propose, for the first time, a response classification based on circulating tumour DNA measurements and its confidence intervals, a "ctDNA-RECIST" that has proven valuable in retrospective studies and goes along with the conventional RECIST classification. We aim to raise the topic for discussion and to encourage analyses of ctDNA data along this line.

Pelvic Insufficiency Fractures and Bone Pain after Radiation Therapy for Anal Cancer: Relation to Pelvic Bone Dose-Volume Parameters.

Purpose: Chemoradiation therapy is the primary treatment for anal cancer. Radiation therapy (RT) can weaken the pelvic bone structure, but the risk of pelvic insufficiency fractures (PIFs) and derived pain in anal cancer is not yet established. We determined the frequency of symptomatic PIFs after RT for anal cancer and related this to radiation dose to specific pelvic bone substructures. Methods and Materials: In a prospective setting, patients treated with RT for anal cancer had magnetic resonance imaging 1 year after RT. PIFs were mapped to 17 different bone sites, and we constructed a guideline for detailed delineation of pelvic bone substructures. Patients were interviewed regarding pain and scored according to Common Terminology Criteria for Adverse Effects. Dose-volume relationships for specific pelvic bone substructures and PIFs were determined for V20 to V40 Gy mean and maximum doses. Results: Twenty-seven patients were included, and 51.9% had PIFs primarily located in the alae of the sacral bone. Patients with PIFs had significantly more pelvic pain (86% vs 23%, P = .001) and 43% had grade 2 bone pain. Dose-volume parameters for sacral bone and sacral alae were significantly higher in patients with PIFs (P < .05). V30 Gy (%) for sacral bone and alae implied an area under the curve of 0.764 and 0.758, respectively, in receiver operating characteristic analyses. Conclusions: We observed a high risk of PIFs in patients treated with RT for anal cancer 1 year after treatment. A significant proportion had pain in the sites where PIFs were most frequently found. Radiation dose to pelvic bone substructures revealed relation to risk of PIFs and can be used for plan optimization in future clinical trials.

One-Year Treatment-Related Side Effects and Quality of Life After Chemoradiotherapy in Squamous Cell Carcinoma of the Anus.

PURPOSE: Patient-reported outcome (PRO) and National Cancer Institute-Common Terminology Criteria for Adverse Events (NCI-CTCAE) data for patients with squamous cell carcinoma of the anus (SCCA) treated with modern radiation therapy (RT) are lacking. The primary aim of this study was to report bowel and bladder PRO and NCI-CTCAE for patients with SCCA 1 year after RT. METHODS AND MATERIALS: From 2015 to 2020, we included patients in a prospective Danish national study. Data were collected before treatment (PT) and 1 year after treatment (1Y) using NCI-CTCAE version 4.0, as well as European Organisation for Research and Treatment of Cancer Quality of Life Questionnaires C30 and CR29. We evaluated the combined PRO scores according to the European Organisation for Research and Treatment of Cancer scoring guidelines, and classified changes according to score difference from PT to 1Y as no change (0-5), minor (5-10), moderate (11-20), and major (>20). Raw scores were reported as frequencies of each of the scores: Not at all, a little, quite a bit, and very much. RESULTS: Of the 270 patients, 81% had complete data sets, including PT and 1Y answers. Functional mean scores were equal to a matched normal population cohort at PT and 1Y. From PT to 1Y, C30 scores were stable despite minor improvements in global health status/quality of life (7.3), emotional functioning (9.3), insomnia (8.0), and appetite loss (7.8). For questionnaire CR29, bowel and bladder symptoms and sore skin improved with minor change (6.2), and buttocks, anal, or rectal pain improved with moderate change (18.3). Flatulence worsened moderately (12.6), and fecal incontinence had minor worsening (7.8). Agreement between PROs and NCI-CTCAE was generally only fair to moderate, especially for quantitative symptoms, such as pain (κ = 0.25). CONCLUSIONS: For patients with SCCA who underwent definitive RT, only a few patients had high scores (indicating quite a bit or very much frequency of bother) regarding bowel and bladder symptoms.

Circulating DNA in patients undergoing loco-regional treatment of colorectal cancer metastases: a systematic review and meta-analysis.

Background: Loco-regional treatment strategies of colorectal cancer (CRC) metastases are evolving, but biological markers that can benefit patients and assist physicians in clinical decisions are lacking. The primary objective of this systematic review and meta-analysis is to investigate the current knowledge on circulating DNA and its clinical utility in predicting outcomes in patients undergoing loco-regional treatment of CRC metastases. Methods: A systematic search of PubMed, Embase, and Cochrane Central Register of Controlled Trials was conducted on March 22, 2022. We included studies on patients undergoing loco-regional treatment of CRC metastases reporting the predictive or prognostic value of circulating DNA in the blood. Hazard ratios (HR) were pooled in separate random-effects meta-analyses to investigate if pre- or post-ablation measurements of circulating DNA were associated with survival. The risk of bias was assessed according to the Quality in Prognosis Studies tool. Results: Twenty-eight studies with 2868 patients were included, of which 16 studies were eligible for meta-analyses. As expected in this new research field, a majority of included studies (n = 21/28) had a high risk of bias in at least one domain. Circulating DNA above the cutoff in a plasma sample taken before loco-regional treatment was associated with a short recurrence-free survival [pooled HR = 2.8, 95% confidence interval (CI) 1.4-5.7, n = 162] and overall survival (pooled HR = 4.7, 95% CI 1.1-20.6, n = 105). Circulating DNA above the cutoff in a plasma sample taken after loco-regional treatment was associated with a short recurrence-free survival (pooled HR = 4.5, 95% CI 3.4-6.1, n = 569) and overall survival (pooled HR = 7.5, 95% CI 2.0-27.3, n = 161). There was limited data on the association between dynamics in circulating DNA and outcome. Conclusions: Measurements of circulating DNA can be valuable when selecting and monitoring patients undergoing loco-regional treatment of CRC metastases. Studies designed to investigate the true clinical utility of circulating DNA in the context of various ablation modalities are warranted.The review has been registered at PROSPERO (ID: CRD42022320032).

Development and validation of prognostic models for anal cancer outcomes using distributed learning: protocol for the international multi-centre atomCAT2 study.

BACKGROUND: Anal cancer is a rare cancer with rising incidence. Despite the relatively good outcomes conferred by state-of-the-art chemoradiotherapy, further improving disease control and reducing toxicity has proven challenging. Developing and validating prognostic models using routinely collected data may provide new insights for treatment development and selection. However, due to the rarity of the cancer, it can be difficult to obtain sufficient data, especially from single centres, to develop and validate robust models. Moreover, multi-centre model development is hampered by ethical barriers and data protection regulations that often limit accessibility to patient data. Distributed (or federated) learning allows models to be developed using data from multiple centres without any individual-level patient data leaving the originating centre, therefore preserving patient data privacy. This work builds on the proof-of-concept three-centre atomCAT1 study and describes the protocol for the multi-centre atomCAT2 study, which aims to develop and validate robust prognostic models for three clinically important outcomes in anal cancer following chemoradiotherapy. METHODS: This is a retrospective multi-centre cohort study, investigating overall survival, locoregional control and freedom from distant metastasis after primary chemoradiotherapy for anal squamous cell carcinoma. Patient data will be extracted and organised at each participating radiotherapy centre (n = 18). Candidate prognostic factors have been identified through literature review and expert opinion. Summary statistics will be calculated and exchanged between centres prior to modelling. The primary analysis will involve developing and validating Cox proportional hazards models across centres for each outcome through distributed learning. Outcomes at specific timepoints of interest and factor effect estimates will be reported, allowing for outcome prediction for future patients. DISCUSSION: The atomCAT2 study will analyse one of the largest available cross-institutional cohorts of patients with anal cancer treated with chemoradiotherapy. The analysis aims to provide information on current international clinical practice outcomes and may aid the personalisation and design of future anal cancer clinical trials through contributing to a better understanding of patient risk stratification.

Circulating cell-free DNA as predictor of pathological complete response in locally advanced rectal cancer patients undergoing preoperative chemoradiotherapy.

Background: The watch and wait (W&W) strategy is proposed for patients with locally advanced rectal cancer (LARC) achieving clinical complete response (cCR) after neoadjuvant radiotherapy. cCR is only in partial concordance with pathological complete response (pCR) due to persisting viable tumour cells. The aim was to investigate circulating-free-deoxyribonucleic-acid (cfDNA) as a biomarker for prediction of pCR. Materials and methods: Patients treated with neoadjuvant radiotherapy for LARC, were included in a prospective biomarker study in Aarhus, Denmark from 2017 to 2020. Plasma cfDNA levels were analysed by a direct fluorescent assay (DFA). Surgical specimens were reviewed by pathologists to categorize response to cytotoxic therapy. Results: In total, 76 patients were included with plasma available at baseline (n = 70), mid therapy (n = 50), and end of therapy (n = 54). Higher cfDNA levels were observed in LARC patients compared with healthy subjects (p < 0.01). By ROC analysis (AUC: 0.87 (95% CI, 0.81-0.92)) the optimal cut-off was 0.71 ng/µL for differentiation between healthy subjects and LARC patients. Thirteen patients obtained pCR with a median cfDNA level of 0.57 ng/µL at end of therapy. Patients with cfDNA levels at end of therapy below the cut-off (p < 0.02) and 'cfDNA responders' with descending levels greater than the 75th percentile during therapy had a significantly higher chance of pCR (p < 0.01). Conclusion: This hypothesis generating study indicates that low cfDNA levels at end of treatment or ´cfDNA responders might be associated with pCR. Quantification of cfDNA by the rapid and feasible DFA analysis could potentially facilitate personalized follow-up as a complementary tool to identify candidates for a W&W strategy.

Circulating tumour DNA and its clinical utility in predicting treatment response or survival in patients with metastatic colorectal cancer: a systematic review and meta-analysis.

BACKGROUND: We investigate the current knowledge on circulating tumour DNA (ctDNA) and its clinical utility in predicting outcomes in patients with metastatic colorectal cancer (mCRC). METHODS: PubMed, Embase, Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Trials were searched. Last search 16/12/2020. We included studies on patients with mCRC reporting the predictive or prognostic value of ctDNA. We performed separate random-effects meta-analyses to investigate if baseline ctDNA and early changes in ctDNA levels during treatment were associated with survival. The risk of bias was assessed according to the Quality in Prognosis Studies tool. RESULTS: Seventy-one studies were included with 6930 patients. Twenty-four studies were included in meta-analyses. High baseline ctDNA level was associated with short progression-free survival (PFS) (HR = 2.2; 95% CI 1.8-2.8; n = 509) and overall survival (OS) (HR = 2.4; 95% CI 1.9-3.1; n = 1336). A small or no early decrease in ctDNA levels during treatment was associated with short PFS (HR = 3.0; 95% CI 2.2-4.2; n = 479) and OS (HR = 2.8; 95% CI 2.1-3.9; n = 583). Results on clonal evolution and lead-time were inconsistent. A majority of included studies (n = 50/71) had high risk of bias in at least one domain. CONCLUSIONS: Plasma ctDNA is a strong prognostic biomarker in mCRC. However, true clinical utility is lacking.

A Machine-Learning-Based Bibliometric Analysis of the Scientific Literature on Anal Cancer.

Squamous-cell carcinoma of the anus (ASCC) is a rare disease. Barriers have been encountered to conduct clinical and translational research in this setting. Despite this, ASCC has been a prime example of collaboration amongst researchers. We performed a bibliometric analysis of ASCC-related literature of the last 20 years, exploring common patterns in research, tracking collaboration and identifying gaps. The electronic Scopus database was searched using the keywords "anal cancer", to include manuscripts published in English, between 2000 and 2020. Data analysis was performed using R-Studio 0.98.1091 software. A machine-learning bibliometric method was applied. The bibliometrix R package was used. A total of 2322 scientific documents was found. The average annual growth rate in publication was around 40% during 2000-2020. The five most productive countries were United States of America (USA), United Kingdom (UK), France, Italy and Australia. The USA and UK had the greatest link strength of international collaboration (22.6% and 19.0%). Two main clusters of keywords for published research were identified: (a) prevention and screening and (b) overall management. Emerging topics included imaging, biomarkers and patient-reported outcomes. Further efforts are required to increase collaboration and funding to sustain future research in the setting of ASCC.