Individual lymph node position variation for rectal cancer patients treated with long course chemoradiotherapy.

Background and purpose: Delivery of high precision radiotherapy lymph node boosts requires detailed information on the interfraction positional variation of individual lymph nodes. In this study we characterized interfraction positional shifts of suspected malignant lymph nodes for rectal cancer patients receiving long course radiotherapy. Furthermore, we investigated parameters which could affect the magnitude of the position variation. Materials and Methods: Fourteen patients from a prospective clinical imaging study with a total of 61 suspected malignant lymph nodes in the mesorectum, presacral, and lateral regions, were included. The primary gross tumor volume (GTVp) and all suspected malignant lymph nodes were delineated on six magnetic resonance imaging scans per patient. Positional variation was calculated as systematic and random errors, based on shifts of center-of-mass, and estimated relative to either bony structures or the GTVp using a hierarchical linear mixed model. Results: Depending on location and direction, systematic and random variations (relative to bony structures) were within 0.6-2.8 mm and 0.6-2.9 mm, respectively. Systematic and random variations increased when evaluating position relative to GTVp (median increase of 0.6 mm and 0.5 mm, respectively). Correlations with scan time-point and relative bladder volume were found in some directions. Conclusions: Using linear mixed modeling, we estimated systematic and random positional variation for suspected malignant lymph nodes in rectal cancer patients treated with long course radiotherapy. Statistically significant correlations of the magnitude of the lymph node shifts were found related to scan time-point and relative bladder volume.

Extracting Systemic Anticancer Treatment Lines from the Danish National Patient Registry for Solid Tumour Patients Treated in the North Denmark Region Between 2009 and 2019.

Background: Reconstructing patient treatment trajectories is important to generate real-world evidence for epidemiological studies. The Danish National Patient Registry (DNPR) contains information about drug prescriptions and could therefore be used to reconstruct treatment trajectories. We aimed to evaluate and enhance two existing methods to reconstruct systemic anticancer treatment trajectories. Methods: This study was based on data from 8738 consecutive patients with solid tumors treated in the North Denmark Region between 2009 and 2019. Two approaches found in the literature as well as two new approaches were applied to the DNPR data. All methods relied on time intervals between two consecutive drug administrations to determine if they belonged to the same treatment line. MedOnc, a local dataset from the Department of Oncology, Aalborg University Hospital was used as a reference. To evaluate the performance of each method, F1-scores were calculated after matching the lines identified in both datasets. We used three different matching strategies: stringent matching, loose matching, and matching based on line numbers, controlling for overfitting. Results: Overall, the two new approaches outperformed the simpler and best performing of the two existing methods, with F1-scores of 0.47 and 0.45 vs 0.44 for stringent matching and 0.84 and 0.83 vs 0.82 for loose matching. Nevertheless, only one of the new methods outperformed the existing simpler method when matching on the number of lines (0.73 vs 0.72). Large differences were seen by cancer site, especially for the stringent and line number matchings. Performances were relatively stable by calendar year. Conclusion: The high F1-scores for the new methods confirm that they should be generally preferred to reconstruct systemic anticancer treatment trajectories using the DNPR.

Treatment planning for patients with low rectal cancer in a multicenter prospective organ preservation study.

BACKGROUND: Non-surgical management of rectal cancer relies on (chemo)radiotherapy as the definitive treatment modality. This study reports and evaluates the clinical high dose radiotherapy treatment plans delivered to patients with low resectable rectal cancer in a Danish multicenter trial. METHODS: The Danish prospective multicenter phase II Watchful Waiting 2 trial (NCT02438839) investigated definitive chemoradiation for non-surgical management of low rectal cancer. Three Danish centers participated in the trial and committed to protocol-specified treatment planning and delivery requirements. The protocol specified a dose of 50.4 Gy in 28 fractions to the elective volume (CTV-/PTV-E) and a concomitant boost of 62 Gy in 28 fractions to the primary target volume (CTV-/PTV-T). RESULTS: The trial included 108 patients, of which 106 treatment plans were available for retrospective analysis. Dose coverage planning goals for the main target structures were fulfilled for 94% of the treatment plans. However, large intercenter differences in doses to organs-at-risk (OARs) were seen, especially for the intestines. Five patients had a V60Gy>10 cm3 for the intestines and two patients for the bladder. CONCLUSION: Prescribed planning goals for target coverage were fulfilled for 94% of the treatment plans, however analysis of OAR doses and volumes indicated intercenter variations. Dose escalation to 62 Gy (as a concomitant boost to the primary tumor) introduced no substantial high dose volumes (>60 Gy) to the bladder and intestines. The treatment planning goals may be used for future prospective evaluation of highdose radiotherapy for organ preservation for low rectal cancer.

International Validation of the Immunoscore Biopsy in Patients With Rectal Cancer Managed by a Watch-and-Wait Strategy.

PURPOSE: No biomarker capable of improving selection and monitoring of patients with rectal cancer managed by watch-and-wait (W&W) strategy is currently available. Prognostic performance of the Immunoscore biopsy (ISB) was recently suggested in a preliminary study. METHODS: This international validation study included 249 patients with clinical complete response (cCR) managed by W&W strategy. Intratumoral CD3+ and CD8+ T cells were quantified on pretreatment rectal biopsies by digital pathology and converted to ISB. The primary end point was time to recurrence (TTR; the time from the end of neoadjuvant treatment to the date of local regrowth or distant metastasis). Associations between ISB and outcomes were analyzed by stratified Cox regression adjusted for confounders. Immune status of tumor-draining lymph nodes (n = 161) of 17 additional patients treated by neoadjuvant chemoradiotherapy and surgery was investigated by 3'RNA-Seq and immunofluorescence. RESULTS: Recurrence-free rates at 5 years were 91.3% (82.4%-100.0%), 62.5% (53.2%-73.3%), and 53.1% (42.4%-66.5%) with ISB High, ISB Intermediate, and ISB Low, respectively (hazard ratio [HR; Low v High], 6.51; 95% CI, 1.99 to 21.28; log-rank P = .0004). ISB was also significantly associated with disease-free survival (log-rank P = .0002), and predicted both local regrowth and distant metastasis. In multivariate analysis, ISB was independent of patient age, sex, tumor location, cT stage (T, primary tumor; c, clinical), cN stage (N, regional lymph node; c, clinical), and was the strongest predictor for TTR (HR [ISB High v Low], 6.93; 95% CI, 2.08 to 23.15; P = .0017). The addition of ISB to a clinical-based model significantly improved the prediction of recurrence. Finally, B-cell proliferation and memory in draining lymph nodes was evidenced in the draining lymph nodes of patients with cCR. CONCLUSION: The ISB is validated as a biomarker to predict both local regrowth and distant metastasis, with a gradual scaling of the risk of pejorative outcome.

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.

Oxaliplatin causes increased offset analgesia during chemotherapy - a feasibility study.

OBJECTIVES: Offset analgesia (OA) is the phenomenon where the perceived pain intensity to heat stimulation disproportionally decreases after a slight decrease in stimulation temperature. The neural mechanisms of OA are not fully understood, but it appears that both peripheral and central temporal filtering properties are involved. Chemotherapy with oxaliplatin often causes acute peripheral sensory neuropathy, and manifests primarily as a cold induced allodynia. The aim of this exploratory patient study was to investigate if OA was affected by the neurotoxic effects of adjuvant oxaliplatin treatment. METHODS: OA was assessed in 17 colon cancer patients during 12 cycles of adjuvant oxaliplatin treatment. The OA response was estimated as the decrease in pain intensity caused by a temperature decrease from 46 °C to 45 °C. Changes in the OA during the treatment period was estimated using a mixed linear model and corrected for multiple comparisons by Sidak's test. RESULTS: OA was increased significantly when assessed before the 2nd, 3rd, 5th, 6th, 9th, and 10th treatment cycle compared to the first (baseline) treatment (p<0.05). CONCLUSIONS: OA is generally decreased in persons suffering from chronic pain or peripheral neuropathy as compared to healthy controls. But in the present study, OA increased during chemotherapy with oxaliplatin. The underlying mechanism of this unexpected increase should be further explored.

The effect of nutritional interventions in acute radiation-induced diarrhoea in patients with primary pelvic cancer: A systematic review.

Acute radiation-induced diarrhoea (RID) is a well-known side effect of external radiation therapy for pelvic cancer. Acute RID is an unresolved clinical problem in approximately 80% of patients. We investigated the effect of nutritional interventions on acute RID in patients with pelvic cancer treated with curative radiotherapy. A search was conducted using PubMed, Embase.com, CINAHL, and Cochrane Library, from 1 January 2005 until 10 October 2022. We included randomised controlled trials or prospective observational studies. Eleven of the 21 identified studies had low quality of evidence, mainly because of low patient numbers distributed among several cancer diagnoses, and non-systematic assessment of acute RID. Interventions included probiotics (n = 6), prebiotics (n = 6), glutamine (n = 4), and others (n = 5). Five studies, of which two provided high quality evidence, showed that probiotics improved acute RID. Future well-designed studies investigating the effects of probiotics on acute RID are warranted. PROSPERO ID: CRD42020209499).

Predictive biomarkers in radioresistant rectal cancer: A systematic review.

BACKGROUND AND AIMS: The treatment of locally advanced rectal cancer often consists of neoadjuvant chemoradiotherapy followed by surgery. However, approximately 15% of patients show no response to this neoadjuvant chemoradiotherapy. This systematic review aimed to identify biomarkers of innate radioresistant rectal cancer. METHOD: Through a systematic literature search, 125 papers were included and analyzed using ROBINS-I, a Cochrane risk of bias tool for non-randomized studies of interventions. Both statistically significant and nonsignificant biomarkers were identified. Biomarkers mentioned more than once in the results or biomarkers with a low or moderate risk of bias were included as the final results. RESULTS: Thirteen unique biomarkers, three genetic signatures, one specific pathway, and two combinations of two or four biomarkers were identified. In particular, the connection between HMGCS2, COASY, and PI3K-pathway seems promising. Future scientific research should focus on further validating these genetic resistance markers.

Feasibility and early clinical impact of precision medicine for late-stage cancer patients in a regional public academic hospital.

AIM: Our goal was to describe a precision medicine program in a regional academic hospital, characterize features of included patients and present early data on clinical impact. MATERIALS AND METHODS: We prospectively included 163 eligible patients with late-stage cancer of any diagnosis from June 2020 to May 2022 in the Proseq Cancer trial. Molecular profiling of new or fresh frozen tumor biopsies was done by WES and RNAseq with parallel sequencing of non-tumoral DNA as individual reference. Cases were presented at a National Molecular Tumor Board (NMTB) for discussion of targeted treatment. Subsequently, patients were followed for at least 7 months. RESULTS: 80% (N = 131) of patients had a successful analysis done, disclosing at least one pathogenic or likely pathogenic variant in 96%. A strongly or potentially druggable variant was found in 19% and 73% of patients, respectively. A germline variant was identified in 2.5%. Median time from trial inclusion to NMTB decision was one month. One third (N = 44) of patients who underwent molecularly profiling were matched with a targeted treatment, however, only 16% were either treated (N = 16) or are waiting for treatment (N = 5), deteriorating performance status being the primary cause of failure. A history of cancer among 1st degree relatives, and a diagnosis of lung or prostate cancer correlated with greater chance of targeted treatment being available. The response rate of targeted treatments was 40%, the clinical benefit rate 53%, and the median time on treatment was 3.8 months. 23% of patients presented at NMTB were recommended clinical trial participation, not dependent on biomarkers. CONCLUSIONS: Precision medicine in end-stage cancer patients is feasible in a regional academic hospital but should continue within the frame of clinical protocols as few patients benefit. Close collaboration with comprehensive cancer centers ensures expert evaluations and equality in access to early clinical trials and modern treatment.

Outcomes of emergency surgical interventions in right-sided colonic cancer: nationwide population-based study based on Danish Colorectal Cancer Group register.

AIM: The aim of this study was to investigate the trends in morbidity and mortality of patients with right-sided colonic cancer who had an emergency surgical procedure in Denmark after the introduction of quality index parameters. METHODS: This was a retrospective nationwide study based on a prospectively maintained Danish Colorectal Cancer Group database focused on right-sided colonic cancer in the interval from 1 May 2001 to 30 April 2018, who underwent emergency surgical intervention (within 48 h of hospital admission). The primary objective was to investigate the trends in morbidity and mortality throughout the study years. Multivariable estimates were adjusted for age, sex, smoking status, alcohol consumption, ASA score classification, tumour localization, type of access to abdominal cavity, surgeon's grade of specialization, and metastatic disease. RESULTS: Out of 2839 patients, a total of 2740 patients fulfilled the inclusion criteria, of whom 2464 underwent right or transverse colon resection (89.9 per cent). The 30-day and 90-day postoperative mortality rates were significantly reduced over the time of the study (OR 0.943, 95 per cent c.i. 0.922 to 0.965, P < 0.001 and OR 0.953, 95 per cent c.i. 0.934 to 0.972, P < 0.001 respectively); however, the complication rates did not follow this trend. Older patients (OR 1.032, 95 per cent c.i. 1.009 to 1.055, P = 0.005) and patients with high ASA scores (OR 1.61, 95 per cent c.i. 1.422 to 1.830, P < 0.001) had higher rates of severe grade 3b postoperative complications. A stoma was constructed in 276 patients (10 per cent), whereas a stent was used in only eight patients. Defunctioning procedures, including stoma construction or colonic stenting (without oncological resection), did not reduce the risk of complications compared with that of definitive surgery. CONCLUSION: The 30-day and 90-day postoperative mortality rates were significantly reduced over the time of the study. Age and ASA score were risk factors for severe postoperative complications.

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.

Trends and drivers of pharmaceutical expenditures from systemic anti-cancer therapy.

Expenditures on medicine for systemic anti-cancer therapy (SACT) have seen large increases in recent years. The characterization of patients with high SACT costs is crucial to identify cost-driving factors, but little is known about the distribution of expenditures at the patient-level. We priced 260,834 registrations of SACT for 12,589 patients from 2008 to 2019 by combining them with product-level billings of EUR 142.1 million. Based on this, we defined high-cost patients as the 2.5% most expensive by accumulated SACT expenditures. We found that high-cost patients accounted for 28.8% of the total SACT expenditures and were observed across all major cancer groups except for pancreatic cancer. The risk of becoming a high-cost patient was increased for younger age groups, i.e., 18-44 and 45-64 years, for patients with BMI ≥ 25, and for patients with multiple cancer diagnoses, while no alteration of risk was observed due to comorbidities or sex. Changes in the characteristics of high-cost patients during the study period were found with an increased risk of becoming high-cost in later years for elderly patients and patients with lung cancer and a decreased risk for breast cancer patients.

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.

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.

High Validity of the Danish National Patient Registry for Systemic Anticancer Treatment Registration from 2009 to 2019.

BACKGROUND: The Danish National Patient Registry is a major resource for Danish epidemiology. Only a few studies have been conducted to check the validity of the reporting of systemic anticancer treatments. In this study, we assessed this validity for a range of cancer types over a long period of time. PATIENTS AND METHODS: We extracted systemic anticancer treatment procedures from the Danish National Patient Registry for patients with solid malignant tumors treated at the Department of Oncology at Aalborg University Hospital between 2009 and 2019 (12,014 patients with 215,293 drug records). These data were compared to records obtained from the antineoplastic prescription database used at the department. We estimated the sensitivity, positive predictive value (PPV), and F1-score defined as the harmonic mean of the sensitivity and the PPV. RESULTS: There was an overall high concordance between the two datasets with a sensitivity and a PPV >92%. Treatments for brain, ovarian and endometrial cancers displayed lower concordance (81-89%). The validity was stable over the study period, with a slight drop during 2016-2017. Most drugs had a high validity with F1-scores above 90%. Fluorouracil, gemcitabine, pemetrexed, pembrolizumab, and nivolumab had F1-scores above 97%. Drugs that were introduced in the study period, such as lapatinib, palbociclib, erlotinib, pertuzumab, and panitumumab, yielded lower F1-scores due to the absence of specific registry codes early after introduction. CONCLUSION: The Danish National Patient Registry can be used to reliably obtain information about systemic anticancer treatments, keeping in mind limitations for recently introduced drugs and for some types of cancer.

Quality of Life in Vulnerable Older Patients with Metastatic Colorectal Cancer Receiving Palliative Chemotherapy-The Randomized NORDIC9-Study.

Quality of life data from randomized trials are lacking in older patients with metastatic colorectal cancer (mCRC). In the randomized NORDIC9-study, reduced-dose S1+oxaliplatin (SOx) showed superior efficacy compared to full-dose S1 monotherapy. We hypothesized that treatment with SOx does not result in inferior quality of life. Patients with mCRC aged ≥70 years and that were not a candidate for standard combination chemotherapy were included and randomly assigned to receive either S1 or SOx. The EORTC QLQ-C30 questionnaire was completed at baseline, after 9, and 18 weeks. The primary endpoint was global Quality of Life (QoL) at 9 weeks. For statistical analysis, a non-inferiority design was chosen applying linear mixed effects models for repeated measurements. The results were interpreted according to statistical significance and anchor-based, clinically relevant between-group minimally important differences (MID). A total of 160 patients aged (median (Interquartile range (IQR))) 78 years (76-81) were included. The QLQ-C30 questionnaire was completed by 150, 100, and 60 patients at baseline, at 9, and 18 weeks, respectively. The difference at 9 weeks in global QoL was 6.85 (95%CI-1.94; 15.65) and 7.37 (0.70; 14.05) in the physical functioning domain in favor of SOx exceeding the threshold for MID. At 18 weeks, the between-group MID in physical functioning was preserved. Dose-reduced combination chemotherapy may be recommended in vulnerable older patients with mCRC, rather than full-dose monotherapy.