Non-operative management after immune checkpoint inhibitors for early-stage, dMMR/MSI-H gastrointestinal cancers.

Surgery is a standard treatment for early-stage gastrointestinal cancers, often preceded by neoadjuvant chemo(radio)therapy or followed by adjuvant therapy. While leading to cure in a proportion of patients, it has some drawbacks such as intra/post-operative complications, mutilation and life-long functional sequelae. Further to the unprecedented efficacy data from studies of immune checkpoint inhibitors for advanced mismatch repair deficient/microsatellite instable (dMMR/MSI-H) tumours, a strong interest has recently emerged for the investigation of such agents in the neoadjuvant setting. Although limited by the exploratory design and small sample size, trials of neoadjuvant immune checkpoint inhibitors for early-stage dMMR/MSI-H gastrointestinal cancers have consistently reported complete response rates ranging from 70 % to 100 %. As a result, the question has arisen as to whether surgery is still needed or organ-preserving strategies should be offered to this especially immuno-sensitive population. In this article, we discuss the available evidence for neoadjuvant immune checkpoint inhibitors in dMMR/MSI-H gastrointestinal cancers and analyse opportunities and challenges to the implementation of non-operative management approaches in this setting.

A multicenter study evaluating efficacy of immune checkpoint inhibitors in advanced non-colorectal digestive cancers with microsatellite instability.

BACKGROUND: One randomized phase III trial comparing chemotherapy (CT) with immune checkpoint inhibitors (ICI) has demonstrated significant efficacy of ICI in deficient DNA mismatch repair system/microsatellite instability-high (dMMR/MSI-H) metastatic colorectal cancer. However, few studies have compared ICI with CT in other advanced dMMR/MSI-H digestive tumors. METHODS: In this multicenter study, we included patients with advanced dMMR/MSI-H non-colorectal digestive tumors treated with chemotherapy and/or ICIs. Patients were divided retrospectively into two groups, a CT group and an immunotherapy (IO) group. The primary endpoint was progression-free survival (PFS). A propensity score approach using the inverse probability of treatment weighting (IPTW) method was applied to deal with potential differences between the two groups. RESULTS: 133 patients (45.1/27.1/27.8% with gastric/small bowel/other carcinomas) were included. The majority of patients received ICI in 1st (29.1%) or 2nd line (44.4%). The 24-month PFS rates were 7.9% in the CT group and 71.2% in the IO group. Using the IPTW method, IO treatment was associated with better PFS (HR=0.227; 95% CI 0.147-0.351; p < 0.0001). The overall response rate was 26.3% in the CT group versus 60.7% in the IO group (p < 0.001) with prolonged duration of disease control in the IO group (p < 0.001). In multivariable analysis, predictive factors of PFS for patients treated with IO were good performance status, absence of liver metastasis and prior primary tumor resection, whereas no association was found for the site of the primary tumor. CONCLUSIONS: In the absence of randomized trials, our study highlights the superior efficacy of ICI compared with standard-of-care therapy in patients with unresectable or metastatic dMMR/MSI-H non-colorectal digestive cancer, regardless of tumor type, with acceptable toxicity.

Retrospective Evaluation of the Prognostic Value of Histological Growth Pattern in Patients with Colorectal Peritoneal Metastases Undergoing Curative-Intent Cytoreductive Surgery.

BACKGROUND: Two distinct histological growth patterns (HGPs) were described in patients with peritoneal metastasis of colorectal cancer origin (PMCRC) with limited Peritoneal Cancer Index (PCI) ≤ 6 who did not receive neoadjuvant chemotherapy (NAC) and were treated with cytoreductive surgery (CRS) ± hyperthermic intraperitoneal chemotherapy (HIPEC): pushing HGP (P-HGP) and infiltrating HGP (I-HGP). Patients with dominant P-HGP (> 50%) had significantly better disease-free survival (DFS) and overall survival (OS). OBJECTIVE: We aimed to determine whether these previous observations regarding the prognostic value of HGP in patients with PMCRC with low PCI (≤ 6) are also valid in all operable patients, regardless of whether they received NAC or not and regardless of PCI score. METHODS: This was a retrospective study including 76 patients who underwent complete CRS ± HIPEC for PMCRC between July 2012 and March 2019. In each patient, up to five of the largest excised peritoneal nodules were analyzed for their tumor-to-peritoneum interface. Correlations between NAC, HGP, and prognosis were further explored. RESULTS: Thirty-seven patients (49%) had dominant P-HGP and 39 (51%) had dominant I-HGP. On univariate analysis, patients with P-HGP ≤ 50% had significantly lower OS than those with dominant P-HGP > 50% (39 versus 60 months; p = 0.014) confirmed on multivariate analysis (hazard ratio 2.4, 95% confidence interval 1.3-4.5; p = 0.006). There were no significant associations between NAC and type of HGP. CONCLUSIONS: This study confirms the prognostic value and reproducibility of the two previously reported HGPs in PMCRC. Dominant P-HGP is associated with better DFS and OS in patients undergoing curative-intent CRS ± HIPEC compared with I-HGP, independently of the extent of peritoneal disease burden.

Primary resistance to immunotherapy in patients with a dMMR/MSI metastatic gastrointestinal cancer: who is at risk? An AGEO real-world study.

BACKGROUND: The outstanding efficacy of immunotherapy in metastatic dMMR/MSI gastro-intestinal (GI) cancers has led to a rapid increase in the number of patients treated. However, 20-30% of patients experience primary resistance to immune checkpoint inhibitors (ICIPR) and need better characterization. METHODS: This AGEO real-world study retrospectively analyzed the efficacy and safety of ICIs and identified clinical variables associated with ICIPR in patients with metastatic dMMR/MSI GI cancers treated with immunotherapy between 2015 and 2022. RESULTS: 399 patients were included, 284 with colorectal cancer (CRC) and 115 with non-CRC, mostly treated by an anti-PD(L)1 (88.0%). PFS at 24 months was 55.8% (95CI [50.8-61.2]) and OS at 48 months was 59.1% (95CI [53.0-65.9]). ORR was 51.0%, and 25.1% of patients were ICIPR. There was no statistical difference in ORR, DCR, PFS, or OS between CRC and non-CRC groups. In multivariable analysis, ICIPR was associated with ECOG-PS ≥ 2 (OR = 3.36), liver metastases (OR = 2.19), peritoneal metastases (OR = 2.00), ≥1 previous line of treatment (OR = 1.83), and age≤50 years old (OR = 1.76). CONCLUSION: These five clinical factors associated with primary resistance to ICIs should be considered by physicians to guide treatment choice in GI dMMR/MSI metastatic cancer patients.

Neoadjuvant chemotherapy for early-stage colon cancer.

Surgery with or without adjuvant chemotherapy is the standard treatment for early-stage colon cancer. However, evidence has recently emerged for neoadjuvant chemotherapy, with the results of randomised clinical trials sparking debates within multidisciplinary teams and splitting the gastrointestinal oncology community. Further to a systematic search of the literature, we provide a thorough and in-depth analysis of the findings from these trials, highlighting the advantages and disadvantages of neoadjuvant chemotherapy. We conclude that, while there is a potential value of moving systemic therapy from the post-operative to the pre-operative setting, the available evidence does not justify a shift in the treatment paradigm of early-stage colon cancer, and surgery with or without adjuvant chemotherapy should remain the standard approach for these patients.

Predictive factors of non-completion of cytoreductive surgery in colorectal peritoneal metastasis.

INTRODUCTION: Cytoreductive surgery (CRS) ± hyperthermic intraperitoneal chemotherapy (HIPEC) is the only potentially curative treatment that can improve the survival prognosis for patients with peritoneal metastasis (PM) of colorectal origin. The main independent prognostic factors are extent of disease, as measured by the Peritoneal Cancer Index (PCI), and completion of CRS (CC-0 or R1). Despite thorough preoperative work-up for selection of surgical candidates, 20%-25 % of CRS procedures are stopped after exploration during laparotomy. These patients undergo "open-and-close" procedures associated with a risk of complications and without any benefit. The aim of this study was to identify preoperative predictors of non-resectability and/or non-completion of CRS in patients with colorectal PMs who were candidates for surgery. MATERIALS AND METHODS: Retrospective, monocentric study including patients admitted for CRS ± HIPEC at the Jules Bordet Institute between January 01, 2010 and December 31, 2021. The preoperative epidemiological, pathological, clinical, radiological, and biological features of patients with unresectable disease were compared with those of patients treated with CRS. RESULTS: One hundred nineteen patients were included, 60 men and 59 women (median age 61 years). Twenty-one CRS procedures (17.65 %) were stopped during exploratory laparotomy. Statistically significant factors associated with non-completion were age (p = 0.0183), PCI (p = 0.0001), presence of sub/occlusive episode(s) prior to CRS (p = 0.0012), and multifocal-diffuse uptakes on PET-scan (p = 0.0017). CONCLUSION: Almost 18 % of patients had an "open-and-close" procedure. PCI was the major determinant of non-completion of CRS. Other predictive factors of unresectability of colorectal PM were age, the presence of sub/occlusive episodes, and PET/CT with multiple peritoneal uptakes.

Prognostic Value of Circulating Cytokines in Chemorefractory Colorectal Cancer.

Circulating cytokines could be optimal biomarkers for prognostication and management decisions in colorectal cancer (CRC). Chemorefractory CRC patients with available plasma samples were included in this study. In the discovery cohort (n = 85), 182 circulating cytokines were tested with a semi-quantitative multiplex assay, and prognostic cytokines were analyzed in the validation cohort (n = 111) by ELISA. Overall survival (OS) was the primary outcome measure, with the false discovery rate (FDR) method (significance level of <0.01) being used to correct for multiple comparisons. Four cytokines were associated with OS in the discovery cohort: insulin-like growth factor-binding protein 1 (IGFBP-1) (HR 2.1 [95%CI: 1.58-2.79], FDR < 0.001), insulin-like growth factor-binding protein 2 (IGFBP-2) (HR 1.65 [95%CI: 1.28-2.13], FDR = 0.006), serum amyloid A (SAA) (HR 1.84 [95%CI: 1.39-2.43], FDR < 0.001), and angiotensin II (HR 1.65 [95%CI: 1.29-2.1], FDR = 0.006). Of these, IGFBP-1 (HR 2.70 [95%CI: 1.56-4.76], FDR = 0.007) and IGFBP-2 (HR 3.33 [95%CI: 1.64-6.67], FDR = 0.008) were confirmed to be independently associated with OS in the validation cohort. Patients with high concentrations of IGFBP-1 and/or IGFBP-2 had a median OS of 3.0 months as compared with 6.9 months for those with low concentrations of both cytokines (HR 2.44 [95%CI: 1.52-4.0], FDR = 0.002) Validation of circulating IGFBP-1 and IGFBP-2 as independent prognostic biomarkers for chemorefractory CRC in larger, independent series is warranted.

Preexisting evidence and outcome of phase III trials in gastrointestinal oncology: a systematic review.

BACKGROUND: A minority of phase III trials in gastrointestinal oncology are positive. We assessed the association between their outcome and the level and characteristics of preexisting evidence. METHODS: EMBASE, PubMed, and proceedings from international meetings were searched for phase III gastrointestinal cancer trials (gastroesophageal, hepatocellular, biliary tract, pancreatic, small bowel, colorectal, anal, stromal, and neuroendocrine) between January 2000 and June 2020. Trials investigating anticancer drugs for advanced disease, with superiority design and standard treatments as control were eligible. The highest level of preexisting evidence was retrieved from the main study report. RESULTS: A total of 193 phase III trials were included, and 69 (35.8%) met their primary endpoint. Positivity rates were as follows: gastroesophageal 37%, colorectal 48%, pancreatic 17.1%, hepatocellular 20%, neuroendocrine 75%, and both biliary tract and GIST 60%. No information about preexisting evidence was found for 44 trials (22.8%). For the remaining 149, preexisting evidence consisted of phase II studies in 123 cases (82.6%) and phase I studies in 26 cases (17.4%). The probability of success was 34.1%, 35.8%, and 35.7%, respectively (P = .934). No parameter from prior studies predicted the outcome of phase III trials except ß < .2 (P = .048). A numerically increased success rate was observed for phase III trials preceded by positive phase II studies (41.9% vs 18.5%, P = .2). CONCLUSIONS: There does not appear to be an association between level of prior evidence and success of phase III gastrointestinal cancer trials. These data, along with the high phase III failure rate, highlight the need to improve the drug development process in this setting.

The Prognostic Value of Distinct Histological Growth Patterns of Colorectal Peritoneal Metastases: A Pilot Study.

BACKGROUND: Different histological growth patterns (HGP) describing the tumor-to-liver interface have been described in colorectal liver metastases and have been associated with a strong prognostic value. However, HGP of peritoneal metastases (PM) of colorectal cancer (CRC) have not yet been described. Our objective was to determine whether distinct HGP can be identified in PMCRC and to evaluate their potential prognostic value in these patients. METHODS: This retrospective study included 38 patients who underwent curative-intent surgery for PMCRC between July 2012 and March 2019, with PCI≤6, and who had not received preoperative chemotherapy. In each patient, the tumor-to-peritoneum interface was evaluated in the excised peritoneal nodules. The association between HGP and postoperative survival was analyzed by using the Kaplan-Meier method. RESULTS: Two distinct HGP were identified: a pushing-type (P-HGP), characterized by a fibrous rim separating the PM and peritoneum, and an infiltrating-type (I-HGP), characterized by focal penetration of tumor cells into the surrounding peritoneal lining without a fibrous rim. Fifteen patients had dominant P-HGP, and 23 patients had dominant I-HGP. Patients with dominant P-HGP (>50% tumor-peritoneum interface) had a significantly better DFS (30 months) than those with P-HGP <50% (9 months; p = 0.029). Patients with a P-HGP dominance >60% had better OS (131 months) than those with P-HGP <60% (41 months; p = 0.044). CONCLUSIONS: This is the first description of two distinct, reproducible HGP in PMCRC. The dominant P-HGP is associated with a favorable prognosis in patients with PMCRC, compared with I-HGP, suggesting that this parameter could ultimately represent a new prognostic biomarker.

Prognostic Value of Preoperative Serological Biomarkers in Patients Undergoing Curative-Intent Cytoreductive Surgery for Colorectal Cancer Peritoneal Metastases.

BACKGROUND: Cytoreductive surgery (CRS) for peritoneal metastases of colorectal cancer (PMCRC) is associated with a high risk of postoperative morbidity, thus making patient selection of upmost importance. Further to data showing an association between preoperative serological biomarkers and patient outcome in various solid tumors, in this study we aim to evaluate their prognostic value in patients with PMCRC treated with curative intent. PATIENTS AND METHODS: This is a retrospective study including patients with PMCRC treated by complete CRS ± HIPEC at our institution between 2011 and 2020. Preoperative serological biomarkers, along with other standard clinicopathological variables, were studied to determine their prognostic value. RESULTS: A total of 94 out of 108 patients met the inclusion criteria. Forty-three patients (46%) presented with synchronous PM. The median peritoneal cancer index (PCI) was 6. On univariate analysis, a higher neutrophil-to-lymphocyte ratio (NLR) was associated with poor prognosis in terms of overall survival (OS) [cutoff 3.567, hazard ratio (HR) 2.8 (1.4-5.3), p = 0.002], whereas a higher platelet-to-lymphocyte ratio (PLR) predicted favorable prognosis in terms of disease-free survival (DFS) [cutoff 185.4, HR 1.9 (1.07-3.53), p = 0.030]. On multivariate analysis, NLR > 3.567, positive lymph nodes (LNs), and PCI > 7 were independent predictive factors for worse OS, whereas NLR > 3.567 and positive LNs were significantly associated with worse DFS. PLR > 185.4 was associated with better DFS. CONCLUSION: High preoperative NLR (> 3.567) and PLR (> 185.4) can predict outcome of patients with PMCRC treated by complete CRS ± HIPEC.

Regorafenib Induces Senescence and Epithelial-Mesenchymal Transition in Colorectal Cancer to Promote Drug Resistance.

Potential intrinsic resistance mechanisms to regorafenib were explored after short exposure (3 days) on five CRC cell lines (HCT-116, SW1116, LS-1034, SW480, Caco-2). The observation of senescence-like features led to the investigation of a drug-initiated phenotype switch. Following long-term exposure (12 months) of HCT-116 and SW480 cell lines to regorafenib, we developed resistant models to explore acquired resistance. SW480 cells demonstrated senescent-like properties, including a cell arrest in the late G2/prophase cell cycle stage and a statistically significant decrease in the expression of G1 Cyclin-Dependent Kinase inhibitors and key cell cycle regulators. A specific senescence-associated secretome was also observed. In contrast, HCT-116 treated cells presented early senescent features and developed acquired resistance triggering EMT and a more aggressive phenotype over time. The gained migration and invasion ability by long-exposed cells was associated with the increased expression level of key cellular and extracellular EMT-related factors. The PI3K/AKT pathway was a significant player in the acquired resistance of HCT-116 cells, possibly related to a PI3KCA mutation in this cell line. Our findings provide new insights into the phenotypic plasticity of CRC cells able, under treatment pressure, to acquire a stable TIS or to use an early senescence state to undergo EMT.

The emerging role of immunotherapy in the treatment of anal cancer.

For decades, chemoradiotherapy for early-stage disease and systemic chemotherapy for advanced disease have represented the mainstay of treatment for anal cancer. Over the last few years, however, the advent of immunotherapy has opened interesting therapeutic perspectives, with the establishment of new standards of care, and the development of clinical trials that may further shape the treatment algorithm for this tumour. In this review article, we discuss the rationale behind the use of immunotherapy for anal cancer and provide an overview of the available clinical data and ongoing efforts to build on these.

Pre-trial quality assurance of diffusion-weighted MRI for radiomic analysis and the role of harmonisation.

PURPOSE: The aim of this study was to perform a quantitative quality assurance of diffusion-weighted MRI to assess the variability of the mean apparent diffusion coefficient (ADC) and other radiomic features across the scanners involved in the REGINA trial. MATERIALS AND METHODS: The NIST/QIBA diffusion phantom was acquired on six 3 T scanners from five centres with a rectum-specific diffusion protocol. All sequences were repeated in each scan session without moving the phantom from the table. Linear interpolation to two isotropic voxel spacing (0.9 and 4 mm) was performed as well as the ComBat feature harmonisation method between scanners. The absolute accuracy error was evaluated for the mean ADC. Repeatability and reproducibility within-subject coefficients of variation (wCV) were computed for 142 radiomic features. RESULTS: For the mean ADC, accuracy error ranged between 0.1 % and 8.5 %, repeatability was <1 % and reproducibility was <3 % for diffusivity range between 0.4 and 1.1x10-3mm2/s. For the other radiomic features, wCV was below 10 % for 24 % and 15 % features for repeatability with resampling 0.9 mm and 4 mm, respectively, and 13 % and 11 % feature for reproducibility. ComBat method could improve significantly the wCV compared to reproducibility without ComBat (p-value < 0.001) but variation was still high for most of the features. CONCLUSION: Our study provided the first investigation of feature selection for development of robust predictive models in the REGINA trial, demonstrating the added value of such a quality assurance process to select conventional and radiomic features in prospective multicentre trials.

Regorafenib in combination with immune checkpoint inhibitors for mismatch repair proficient (pMMR)/microsatellite stable (MSS) colorectal cancer.

Immune checkpoint inhibitors (ICIs) have marked a new era of cancer treatment, showing remarkable efficacy in a wide range of solid malignancies. In colorectal cancer (CRC), however, the therapeutic potential of ICIs is limited to the small group (≈5%) of patients with mismatch repair deficient (dMMR)/high microsatellite instable (MSI-H) tumours, which are characterised by high mutational/neo-antigen burden, and an inflammatory tumour microenvironment with abundant tumour-infiltrating lymphocytes. Over the last few years, research has focused on immuno-modulatory strategies that could overcome the inherent resistance to ICIs that is observed in the vast group (≈95%) of patients with mismatch repair proficient (pMMR)/microsatellite stable (MSS) tumours. Among these, the combination of ICIs with multi-kinase inhibitors has gained traction in preclinical studies and clinical trials. Thanks to their multiple targets and mechanisms of action, generally involving key cancer pathways such as oncogenesis, angiogenesis, metastasis, and tumour immunity, these agents can exert synergistic effects with ICIs, eventually turning inherently cold cancers into hot tumours, that can be efficiently recognised and targeted by an activated immune system. Regorafenib is routinely used for chemorefractory CRC with limited efficacy. Preliminary evidence, however, suggests that this multi-kinase inhibitor could be an optimal combination partner for ICIs. In this review article, we explain the biological rationale underlying the synergism between regorafenib and ICIs, discuss the available clinical data in CRC, and take a glance into future perspectives by presenting ongoing trials and possible research developments in this setting.

Circulating DNA in the neoadjuvant setting of early stage colon cancer.

BACKGROUND: While circulating tumour (ct)DNA is an indicator of minimal residual disease and negative prognostic factor in stage II-III colon cancer, no study has ever analysed the value of this biomarker in colon cancer patients treated with neoadjuvant chemotherapy. We sought to fill this gap by using prospectively collected plasma samples from 80 stage III colon cancer patients, receiving one cycle of neoadjuvant FOLFOX followed by surgery +/- adjuvant FOLFOX in the PePiTA trial. MATERIAL AND METHODS: Samples were collected at baseline, 2 weeks and surgery. NPY and WIF1 were selected as universal methylation markers for ctDNA, and analysed with ddPCR technology. ROC curves were applied for cut-off points, and outcome measures included 5-year disease-free survival (DFS) and 6-year overall survival (OS). RESULTS: After a median follow-up of 52.5 months, baseline circulating-free (cf) DNA was an independent prognostic factor for DFS (HR 3.35, 95% CI: 1.15-9.77, p = .03), and a trend towards a similar association was observed for relative cfDNA changes between baseline and surgery (HR 2.57, 95% CI: 0.94-7.05, p = .07). Among 60 ctDNA assessable patients, 25 (42%) had detectable ctDNA at baseline. While detection of ctDNA at any pre-operative timepoint was not associated with outcome, patients with ctDNA increase (change of the worst trending methylation marker ≥11%, or mean ctDNA change of NPY and WIF1 ≥ 0%) between baseline and surgery showed a trend towards worse 5-year DFS (HR 3.66, 95% CI: 0.81-16.44, p = .09). CONCLUSION: This is the first study of ctDNA in the neoadjuvant setting of early-stage colon cancer. Results are hypothesis-generating and should be confirmed in larger series.

Mind the target: human epidermal growth factor receptor 2 in colorectal cancer.

PURPOSE OF REVIEW: In this article, we briefly summarise the current knowledge about human epidermal growth factor receptor 2 (HER2) alterations in colorectal cancer (CRC) and provide an overview of the latest published evidence especially regarding standardisation of detection methods/diagnostic criteria, prognostication, prediction and targeted treatments. RECENT FINDINGS: Over the last 18 months, the results of many studies have been presented confirming the therapeutic potential of established anti-HER2 agents either as a monotherapy or in combination, as well as new anti-HER2 agents like antibody-drug-conjugates and tyrosine kinase inhibitors. Also, we have seen confirmation of the utility of liquid biopsy and ctDNA analyses as tool for HER2 detection and patient selection. SUMMARY: Despite concerning only 5% of metastatic CRC, HER2 represents a valuable target for emerging anti-HER2 therapies that might significantly improve the outcome of these patients. Standardising HER2 detection methods/diagnostic criteria, and producing high-quality, randomised evidence are the next challenges to meet the standards of regulatory authorities and ultimately have anti-HER2 agents available for use in routine practice.