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Purpose: Detection of persistent circulating tumor DNA (ctDNA) after curative-intent surgery can identify patients with minimal residual disease (MRD) who will ultimately recur. Most ctDNA MRD assays require tumor sequencing to identify tumor-derived mutations to facilitate ctDNA detection, requiring tumor and blood. We evaluated a plasma-only ctDNA assay integrating genomic and epigenomic cancer signatures to enable tumor-uninformed MRD detection. Experimental Design: A total of 252 prospective serial plasma specimens from 103 patients with colorectal cancer undergoing curative-intent surgery were analyzed and correlated with recurrence. Results: Of 103 patients, 84 [stage I (9.5%), II (23.8%), III (47.6%), IV (19%)] had evaluable plasma drawn after completion of definitive therapy, defined as surgery only (n = 39) or completion of adjuvant therapy (n = 45). In “landmark” plasma drawn 1-month (median, 31.5 days) after definitive therapy and >1 year follow-up, 15 patients had detectable ctDNA, and all 15 recurred [positive predictive value (PPV), 100%; HR, 11.28 (P < 0.0001)]. Of 49 patients without detectable ctDNA at the landmark timepoint, 12 (24.5%) recurred. Landmark recurrence sensitivity and specificity were 55.6% and 100%. Incorporating serial longitudinal and surveillance (drawn within 4 months of recurrence) samples, sensitivity improved to 69% and 91%. Integrating epigenomic signatures increased sensitivity by 25%–36% versus genomic alterations alone. Notably, standard serum carcinoembryonic antigen levels did not predict recurrence [HR, 1.84 (P = 0.18); PPV = 53.9%]. Conclusions: Plasma-only MRD detection demonstrated favorable sensitivity and specificity for recurrence, comparable with tumor-informed approaches. Integrating analysis of epigenomic and genomic alterations enhanced sensitivity. These findings support the potential clinical utility of plasma-only ctDNA MRD detection. See related commentary by Bent and Kopetz, p. 5449

Background Survival in patients with metastatic colorectal cancer (mCRC) has been associated with tumor mutational status, muscle loss, and weight loss. We sought to explore the combined effects of these variables on overall survival. Materials and Methods We performed an observational cohort study, prospectively enrolling patients receiving chemotherapy for mCRC. We retrospectively assessed changes in muscle (using computed tomography) and weight, each dichotomized as >5% or ≤5% loss, at 3, 6, and 12 months after diagnosis of mCRC. We used regression models to assess relationships between tumor mutational status, muscle loss, weight loss, and overall survival. Additionally, we evaluated associations between muscle loss, weight loss, and tumor mutational status. Results We included 226 patients (mean age 59 ± 13 years, 53% male). Tumor mutational status included 44% wild type, 42% RAS‐mutant, and 14% BRAF‐mutant. Patients with >5% muscle loss at 3 and 12 months experienced worse survival controlling for mutational status and weight (3 months hazard ratio, 2.66; p < .001; 12 months hazard ratio, 2.10; p = .031). We found an association of >5% muscle loss with BRAF‐mutational status at 6 and 12 months. Weight loss was not associated with survival nor mutational status. Conclusion Increased muscle loss at 3 and 12 months may identify patients with mCRC at risk for decreased overall survival, independent of tumor mutational status. Specifically, >5% muscle loss identifies patients within each category of tumor mutational status with decreased overall survival in our sample. Our findings suggest that quantifying muscle loss on serial computed tomography scans may refine survival estimates in patients with mCRC. Implications for Practice In this study of 226 patients with metastatic colorectal cancer, it was found that losing >5% skeletal muscle at 3 and 12 months after the diagnosis of metastatic disease was associated with worse overall survival, independent of tumor mutational status and weight loss. Interestingly, results did not show a significant association between weight loss and overall survival. These findings suggest that muscle quantification on serial computed tomography may refine survival estimates in patients with metastatic colorectal cancer beyond mutational status., Cancer cachexia has traditionally been defined using weight loss; however, loss of skeletal muscle may be a more objective measure. This article reports the results of a retrospective study that assessed whether skeletal muscle loss is associated with overall survival in patients with metastatic colorectal cancer, independent of tumor mutational status and weight loss.

Purpose: ctDNA offers a promising, noninvasive approach to monitor therapeutic efficacy in real-time. We explored whether the quantitative percent change in ctDNA early after therapy initiation can predict treatment response and progression-free survival (PFS) in patients with metastatic gastrointestinal cancer. Experimental Design: A total of 138 patients with metastatic gastrointestinal cancers and tumor profiling by next-generation sequencing had serial blood draws pretreatment and at scheduled intervals during therapy. ctDNA was assessed using individualized droplet digital PCR measuring the mutant allele fraction in plasma of mutations identified in tumor biopsies. ctDNA changes were correlated with tumor markers and radiographic response. Results: A total of 138 patients enrolled. A total of 101 patients were evaluable for ctDNA and 68 for tumor markers at 4 weeks. Percent change of ctDNA by 4 weeks predicted partial response (PR, P < 0.0001) and clinical benefit [CB: PR and stable disease (SD), P < 0.0001]. ctDNA decreased by 98% (median) and >30% for all PR patients. ctDNA change at 8 weeks, but not 2 weeks, also predicted CB (P < 0.0001). Four-week change in tumor markers also predicted response (P = 0.0026) and CB (P = 0.022). However, at a clinically relevant specificity threshold of 90%, 4-week ctDNA change more effectively predicted CB versus tumor markers, with a sensitivity of 60% versus 24%, respectively (P = 0.0109). Patients whose 4-week ctDNA decreased beyond this threshold (≥30% decrease) had a median PFS of 175 days versus 59.5 days (HR, 3.29; 95% CI, 1.55–7.00; P < 0.0001). Conclusions: Serial ctDNA monitoring may provide early indication of response to systemic therapy in patients with metastatic gastrointestinal cancer prior to radiographic assessments and may outperform standard tumor markers, warranting further evaluation.

Background Sub-Saharan Africa is simultaneously facing a rising incidence of cancer and a dearth of medical professionals because of insufficient training numbers and emigration, creating a growing shortage of cancer care. To combat this, Massachusetts General Hospital and Beth Israel Deaconess Medical Center partnered with institutions in South Africa, Tanzania, and Rwanda to develop a fellowship exchange program to supplement the training of African oncologists practicing in their home countries. Methods In its initial year, 2018, the Program for Enhanced Training in Cancer (POETIC) hosted a pilot cohort of seven fellows for 3-week observerships in their areas of interest. Researchers distributed questionnaires for program evaluation to participants prior to arrival and upon departure; additionally, three participated in semistructured interviews. Results Five themes emerged from the qualitative data: expectations of POETIC, differences between oncology in the U.S. and in sub-Saharan Africa, positive elements of the program, areas for improvement, and potential impact. Fellows identified several elements of Western health care that will inform their practice: patient-centered care; clinical trials; and collaboration among medical, radiation, and surgical oncologists. From the quantitative data, feedback was primarily around logistical areas for improvement. Conclusion POETIC was found to be feasible and valuable. The results from the pilot year justify the program's continuation in hopes of strengthening global health partnerships to support oncology training in Africa. One weakness is the small number of fellows, which will limit the impact of the study and the relevance of its conclusions. Future research will report on the expansion of the program and follow-up with former participants. Implications for Practice This work presents a novel model for fellowship exchange between lower- and higher-resourced areas. The program is a short-term observership with tumor boards and didactic teaching sessions incorporated. By attracting oncologists who aim to practice in their home countries, it facilitates international collaboration without contributing to the preexisting lack of medical professionals in low- and middle-income countries.

PURPOSE Sub-Saharan Africa is simultaneously facing a rising incidence of cancer and a dearth of medical professionals as a result of insufficient training numbers and emigration, creating a growing shortage of cancer care. To combat this, Massachusetts General Hospital and Beth Israel Deaconess Medical Center partnered with institutions in South Africa, Tanzania, and Rwanda to develop a fellowship exchange program to supplement the training of African oncologists practicing in their home countries. METHODS In its initial 2 years (2018 and 2019), the Program for Enhanced Training in Cancer (POETIC) hosted a pilot cohort of 14 fellows for 3-week observerships in their areas of interest. Researchers distributed questionnaires for program evaluation to participants before arrival and upon departure, and 8 participated in semistructured interviews. RESULTS Five themes emerged from the qualitative data: expectations of POETIC, differences in oncology between the United States and sub-Saharan Africa, positive elements of the program, areas for improvement, and potential impact. Fellows identified several elements of Western health care that will inform their practice: patient-centered care, research development, and collaboration among medical, radiation, and surgical oncologists. The time in Boston modeled a research infrastructure that participants expressed interest in emulating at their home hospitals. In addition, the fellowship inspired some participants to address prevention and survivorship efforts in their home countries. From the quantitative data, feedback was primarily around logistical areas for improvement. CONCLUSION POETIC was found to be feasible and valuable. The results from the first years justify the program’s continuation in hopes of strengthening global health partnerships to support oncology training in Africa. One weakness is the small number of fellows, which will limit the impact of the study and the relevance of its conclusions. Future work will involve long-term follow up with participants and the development of an alumni network.

Hydrogen sulfide (H2S) affects vascular resistance; however, its effect on the hepatic microcirculation has not been investigated. Hepatic sinusoidal perfusion is dysregulated during sepsis, contributing to liver injury. Therefore, the present study determined the effect of H2S on the hepatic microcirculation and the contribution of endogenous H2S to hepatic microcirculatory dysfunction in an endotoxin model of sepsis. Portal infusion of H2S increased portal pressure in vivo (6.8 ± 0.2 mmHg before H2S vs. 8.6 ± 0.8 mmHg peak during H2S infusion, P < 0.05). Using intravital microscopy, we observed decreased sinusoidal diameter (6.2 ± 0.27 μm before H2S vs. 5.7 ± 0.3 μm after H2S, P < 0.05) and increased sinusoidal heterogeneity during H2S infusion ( P < 0.05) and net constriction. Since hepatic H2S levels are elevated during sepsis, we used the cystathionine γ lyase inhibitor dl-propargylglycine (PAG) to determine the contribution of H2S to the hypersensitization of the sinusoid to the vasoconstrictor effect of endothelin-1 (ET-1). PAG treatment significantly attenuated the sinusoidal sensitization to ET-1 in endotoxin-treated animals. ET-1 infusion increased portal pressure to 175% of baseline in endotoxemic animals, which was reduced to 143% following PAG treatment ( P < 0.05). PAG abrogated the increase in sinusoidal constriction after ET-1 infusion in LPS-treated rats (30.9% reduction in LPS rats vs. 11.6% in PAG/LPS rats, P < 0.05). Moreover, PAG treatment significantly attenuated the increase in NADH fluorescence following ET-1 exposure during endotoxemia (61 grayscale units LPS vs. 21 units in PAG/LPS, P < 0.05), suggesting an improvement in hepatic oxygen availability. This study is the first to demonstrate a vasoconstrictor action of H2S on the hepatic sinusoid and provides a possible mechanism for the protective effect of PAG treatment during sepsis.