Utility of Circulating Tumor DNA Assessment in Characterizing Recurrence Sites after Optimal Resection for Metastatic Colorectal Cancer.

INTRODUCTION: Plasma ctDNA is a promising biomarker for metastatic colorectal cancer (mCRC); however, its role in characterizing recurrence sites after mCRC resection remains poorly understood. This single-institution study investigated the timing of ctDNA detection and its levels in the context of recurrence at different sites following mCRC resection. METHODS: Patients who underwent optimal resection of CRC metastases involving the peritoneum, distant lymph nodes, or liver, with serial postoperative tumor-informed ctDNA assessments (Signatera) were included. Recurrence sites, as defined by surveillance imaging or laparoscopy, were categorized as peritoneal-only and other distant sites (liver, lung, lymph nodes, or body wall). RESULTS: Among the 31 included patients, ctDNA was detected in all 26 (83.4%) patients with postoperative recurrence and was persistently undetectable in five patients who did not experience recurrence. At three months post-surgery, ctDNA was detected in 2/8 (25.0%) patients with peritoneal-only recurrence and 17/18 (94.4%) patients with distant recurrence (p < 0.001). Beyond three months, ctDNA was detected in the remaining six patients with peritoneal-only disease and one patient with distant disease. ctDNA detection preceded the clinical diagnosis of recurrence by a median of nine weeks in both groups. At recurrence, peritoneal-only recurrent cases exhibited lower ctDNA levels (median 0.4 MTM/ml, IQR 0.1-0.8) compared to distant recurrence (median 5.5 MTM/ml, IQR 0.8-33.3, p = 0.004). CONCLUSION: Peritoneal-only recurrence was associated with delayed ctDNA detection and low levels of ctDNA after optimal resection for mCRC. ctDNA testing may effectively characterize recurrence sites and may help guide subsequent treatments specific to the disease sites involved.

Fragmentation of Care in Patients with Peritoneal Metastases Undergoing Cytoreductive Surgery.

BACKGROUND: The delivery of multimodal treatment at a high-volume center is known to optimize the outcomes of gastrointestinal malignancies. However, patients undergoing cytoreductive surgery (CRS) for peritoneal metastases often must 'fragment' their surgical and systemic therapeutic care between different institutions. We hypothesized that this adversely affects outcomes. PATIENTS AND METHODS: Adults undergoing CRS for colorectal or appendiceal adenocarcinoma at our institution between 2016 and 2022 were identified retrospectively and grouped by care network: 'coordinated care' patients received exclusively in-network systemic therapy, while 'fragmented care' patients received some systemic therapy from outside-network providers. Factors associated with fragmented care were also ascertained. Overall survival (OS) from CRS and systemic therapy-related serious adverse events (SAEs) were compared across the groups. RESULTS: Among 85 (80%) patients, 47 (55%) had colorectal primaries and 51 (60%) received fragmented care. Greater travel distance [OR 1.01 (CI 1.00-1.02), p = 0.02] and educational status [OR 1.04 (CI 1.01-1.07), p = 0.01] were associated with receiving fragmented care. OS was comparable between patients who received fragmented and coordinated care in the colorectal [32.5 months versus 40.8 months, HR 0.95 (CI 0.43-2.10), p = 0.89] and appendiceal [31.0 months versus 27.4 months, HR 1.17 (CI 0.37-3.74), p = 0.55] subgroups. The frequency of SAEs (7.8% versus 17.6%, p = 0.19) was also similar. CONCLUSIONS: There were no significant differences in survival or SAEs based on the networks of systemic therapy delivery. This suggests that patients undergoing CRS at a high-volume center may safely receive systemic therapy at outside-network facilities with comparable outcomes.

Group 2 Innate Lymphoid Cells Coordinate Damage Response in the Stomach.

BACKGROUND & AIMS: Severe injury to the lining of the stomach leads to changes in the epithelium (reprogramming) that protect and promote repair of the tissue, including development of spasmolytic polypeptide-expressing metaplasia (SPEM) and tuft and foveolar cell hyperplasia. Acute gastric damage elicits a type-2 inflammatory response that includes production of type-2 cytokines and infiltration by eosinophils and alternatively activated macrophages. Stomachs of mice that lack interleukin 33 (IL33) or interleukin 13 (IL13) did not undergo epithelial reprogramming after drug-induced injury. We investigated the role of group 2 innate lymphoid cells (ILC2s) in gastric epithelial repair. METHODS: Acute gastric injury was induced in C57BL/6J mice (wild-type and RAG1 knockout) by administration of L635. We isolated ILC2s by flow cytometry from stomachs of mice that were and were not given L635 and performed single-cell RNA sequencing. ILC2s were depleted from wild-type and RAG1-knockout mice by administration of anti-CD90.2. We assessed gastric cell lineages, markers of metaplasia, inflammation, and proliferation. Gastric tissue microarrays from patients with gastric adenocarcinoma were analyzed by immunostaining. RESULTS: There was a significant increase in the number of GATA3-positive ILC2s in stomach tissues from wild-type mice after L635-induced damage, but not in stomach tissues from IL33-knockout mice. We characterized a marker signature of gastric mucosal ILC2s and identified a transcription profile of metaplasia-associated ILC2s, which included changes in expression of Il5, Il13, Csf2, Pd1, and Ramp3; these changes were validated by quantitative polymerase chain reaction and immunocytochemistry. Depletion of ILC2s from mice blocked development of metaplasia after L635-induced injury in wild-type and RAG1-knockout mice and prevented foveolar and tuft cell hyperplasia and infiltration or activation of macrophages after injury. Numbers of ILC2s were increased in stomach tissues from patients with SPEM compared with patients with normal corpus mucosa. CONCLUSIONS: In analyses of stomach tissues from mice with gastric tissue damage and patients with SPEM, we found evidence of type 2 inflammation and increased numbers of ILC2s. Our results suggest that ILC2s coordinate the metaplastic response to severe gastric injury.

Association of osteopenia and osteoporosis with higher rates of pseudarthrosis and revision surgery in adult patients undergoing single-level lumbar fusion.

OBJECTIVE: Patients with osteopenia or osteoporosis who require surgery for symptomatic degenerative spondylolisthesis may have higher rates of postoperative pseudarthrosis and need for revision surgery than patients with normal bone mineral densities (BMDs). To this end, the authors compared rates of postoperative pseudarthrosis and need for revision surgery following single-level lumbar fusion in patients with normal BMD with those in patients with osteopenia or osteoporosis. The secondary outcome was to investigate the effects of pretreatment with medications that prevent bone loss (e.g., teriparatide, bisphosphonates, and denosumab) on these adverse outcomes in this patient cohort. METHODS: Patients undergoing single-level lumbar fusion between 2007 and 2017 were identified. Based on 1:1 propensity matching for baseline demographic characteristics and comorbidities, 3 patient groups were created: osteopenia (n = 1723, 33.3%), osteoporosis (n = 1723, 33.3%), and normal BMD (n = 1723, 33.3%). The rates of postoperative pseudarthrosis and revision surgery were compared between groups. RESULTS: The matched populations analyzed in this study included a total of 5169 patients in 3 groups balanced at baseline, with equal numbers (n = 1723, 33.3%) in each group: patients with a history of osteopenia, those with a history of osteoporosis, and a control group of patients with no history of osteopenia or osteoporosis and with normal BMD. A total of 597 complications were recorded within a 2-year follow-up period, with pseudarthrosis (n = 321, 6.2%) being slightly more common than revision surgery (n = 276, 5.3%). The odds of pseudarthrosis and revision surgery in patients with osteopenia were almost 2-fold (OR 1.7, 95% CI 1.26-2.30) and 3-fold (OR 2.73, 95% CI 1.89-3.94) higher, respectively, than those in patients in the control group. Similarly, the odds of pseudarthrosis and revision surgery in patients with osteoporosis were almost 2-fold (OR 1.92, 95% CI 1.43-2.59) and > 3-fold (OR 3.25, 95% CI 2.27-4.65) higher, respectively, than those in patients in the control group. Pretreatment with medications to prevent bone loss prior to surgery was associated with lower pseudarthrosis and revision surgery rates, although the differences did not reach statistical significance. CONCLUSIONS: Postoperative pseudarthrosis and revision surgery rates following single-level lumbar spinal fusion are significantly higher in patients with osteopenia and osteoporosis than in patients with normal BMD. Pretreatment with medications to prevent bone loss prior to surgery decreased these complication rates, although the observed differences did not reach statistical significance.