Survival Outcomes of Cytoreductive Surgery with HIPEC in Gastric Adenocarcinoma: A National Cancer Database Study.

BACKGROUND: This study aimed to assess the impact of cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) on the survival outcomes for patients with gastric cancer and peritoneal carcinomatosis (PC). METHODS: A retrospective analysis of the National Cancer Database from 2004 to 2020 identified patients with topography and histology codes consistent with gastric adenocarcinoma who underwent CRS/HIPEC. The exclusion criteria ruled out known other distant metastasis and missing key data. The study compared the CRS/HIPEC group with patients who had stage IV disease (with the same exclusions for distant metastases) and received systemic chemotherapy but no surgery to the primary site. RESULTS: The study included 148 patients who underwent CRS/HIPEC. Their median age was 57 years (interquartile range [IQR], 47-66 years), with 57.4% of the patients identifying as male and 73.6% identifying as white. Most of the CRS/HIPEC patients had locally advanced disease, with 33.8% having pT4 disease and 23% patients having pN3 status. The Charlson-Deyo scores were 0 for 77% and 1 for 16.9% of the patients. The overall survival (OS) among the stage IV patients managed with CRS/HIPEC was significantly longer than for the patients receiving only systemic chemotherapy (median survival, 18.1 vs 9.3 months; p < 0.001), and the 1-year OS was 72.6% versus 38.8% (p < 0.05)). Among the stage IV patients, CRS/HIPEC showed better survival than systemic chemotherapy (hazard ratio [HR], 0.57; 95% confidence interval [CI], 0.44-0.73; p < .001) when control was used for the Charlson Deyo score, histology, age, and sex. CONCLUSIONS: These results suggest the association of CRS/HIPEC with improved survival for selected patients with gastric adenocarcinoma and peritoneal disease. Some of this difference may have been due to selection bias, but the differences in the survival curves are robust.

Rare Case of Metachronous Gastric Metastasis from Primary Ovarian Carcinoma.

Metastasis of ovarian cancer to the stomach is extremely rare. The tumors most commonly metastasizing to the stomach include melanoma, breast, lung, and oesophageal carcinoma, while ovarian cancer comprises only 0.013-1.6% of all gastric metastatic tumors. The aim of this study was to present a rare case of an isolated metachronous gastric metastasis from an ovarian carcinoma, in a 59-year-old lady. A 59-year-old lady presented with a right adnexal mass on MRI imaging of the abdomen and pelvis and an elevated serum CA 125 of 4240 IU/ml. She underwent a primary cytoreductive surgery comprising of omentectomy, peritoneal biopsies, pelvic peritonectomy and peritoneal washing cytology, hysterectomy and bilateral salpingo-oophorectomy, and a retroperitoneal and pelvic nodal dissection. The surgical Peritoneal Carcinomatosis Index (PCI) was 5. The final histopathology showed a high-grade serous adenocarcinoma involving the right adnexa. She received six cycles of adjuvant chemotherapy. On a 3-monthly follow-up, the PET scan revealed that a gastric fundic lesion was noted. Investigations revealed a metachronous metastasis from the serous carcinoma of the ovary, confirmed by histopathological evaluation. The patient was treated with surgical resection of the metastasis and systemic chemotherapy to achieve disease control. Gastric metastasis from ovarian cancer should be considered a differential diagnosis in any patient presenting with a gastric mass and a history of ovarian cancer.

Collision tumor of pulmonary adenocarcinoma and small lymphocytic lymphoma: A rare case of concurrent malignancies in the same lymph node.

BACKGROUND: Collision tumors, a rare and challenging diagnostic entity, are characterized by the simultaneous presence of two distinct histological neoplasms within the same anatomical site. The underlying mechanisms of collision tumors are not well understood, though various theories attempt to explain this phenomenon. CASE PRESENTATION: A 77-year-old Palestinian man, a heavy smoker with multiple comorbidities, presented with a productive cough and significant weight loss. Computed tomography (CT) scan with IV contrast revealed extensive pulmonary involvement, mediastinal lymphadenopathy, and adrenal gland nodules. An excisional biopsy of a lymph node confirmed the presence of both metastatic pulmonary adenocarcinoma and small Lymphocytic Lymphoma (SLL) through histopathological and immunohistochemical analyses. DISCUSSION: Collision tumors have been documented in various anatomical sites, such as the lung, gastrointestinal tract, skin, and genitourinary system. However, their occurrence in lymph nodes is exceptionally rare. Additionally, to our knowledge, a collision tumor involving both pulmonary adenocarcinoma and small lymphocytic lymphoma within the same lymph node has not been previously reported. CONCLUSION: Collision tumors are uncommon and should be considered in the differential diagnosis of complex oncological cases. Accurate diagnosis requires comprehensive investigations, including imaging studies and detailed pathological examinations.

Leptomeningeal metastases in prostate cancer: A review of the current literature.

Leptomeningeal metastasis/leptomeningeal carcinomatosis (LMC; terms used interchangeably) is an inflammatory complication of primary tumors that involves the spread of the disease to the meninges (specifically the arachnoid and pia maters) and spinal cord. In the United States, approximately 110,000 new cases are diagnosed each year, and the prognosis is usually poor. Complications of LMC include cognitive impairment, cranial nerve dysfunction, ischemic stroke, and mortality. The survival times of untreated and treated LMC are approximately 4-6 weeks and 2-4 months, respectively. Leptomeningeal carcinomatoses are usually metastatic cancers that spread to the central nervous system. Although lung and breast cancers have a clearly defined relationship with LMC, it remains unclear whether prostate cancer (PC) is also directly associated with LMC. To determine whether such association exists, we conducted a PubMed review of the literature on patients with PC with coexisting LMCs. Our search yielded 23 case reports of patients with preexisting PC who developed LMC. In addition, 2 retrospective cohort studies were examined. Various findings were identified in the revised cases and studies. The first 3 findings were related to the progression of the disease: patients presenting with neurological disease symptoms were in remission from PC for 7 years on average, LMCs tended to occur after other cancer diagnoses, and the disease had already rapidly progressed by the time the symptoms were present. Regarding diagnosis, the major finding was that most LMCs were detected by magnetic resonance imaging (which does not detect early dissemination), and it was suggested that single-photon emission computed tomography or positron emission tomography imaging could be used for earlier detection. Finally, in terms of treatment, the main finding was that treatment was palliative rather than curative and that prognosis remained poor despite treatment. On the basis of these results, we recommend for individuals with risk factors, such as high-grade PC and hormonal PC, to be evaluated on a case-by-case basis for increased surveillance of LMC development.

How to Implement Pressurized Intraperitoneal Aerosol Chemotherapy into a National Health System Scenario: A Single-Center Retrospective Analysis of Costs and Economic Sustainability at a High-Volume Italian Hospital.

PIPAC is a new surgical procedure and a viable treatment option for PSM patients, due to promising therapeutic outcomes, minimal invasiveness, limited surgical morbidity, and systemic toxicity side effects. However, its implementation throughout hospitals is hard to obtain due to its fragile economical sustainability. A retrospective health economic analysis was conducted in order to evaluate the cost of hospitalization for patients undergoing PIPAC treatment at Fondazione Policlinico Universitario Agostino Gemelli, IRCCS, in Rome. The average cost of a PIPAC procedure was defined based on the cost of surgery (cost of surgical material, operating room, intraperitoneal chemotherapy), hospital stay, diagnostic examinations, and drugs used during the stay. A total of 493 PIPAC procedures were performed on 222 patients with peritoneal metastases or primary peritoneal cancer from 2017 to 2023. Since the mean remuneration for each PIPAC hospitalization is €5916 and the mean expenditure per hospitalization is €6538, this results in an operating profit per PIPAC hospitalization of -€622. The reimbursement of PIPAC treatment by the Italian National Health System currently only partially covers the hospital's costs. Development of specific codes and adequate reimbursement for PIPAC by recognizing this procedure as a proper treatment for peritoneal carcinomatosis is essential.

Flourine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Imaging of Peritoneal Carcinomatosis in Lung Cancer: A Case Study.

Lung cancer with peritoneal carcinomatosis (PC) is a rare disease presentation. The presence of peritoneal disease is a sign of poor prognosis and is hard to diagnose. Flourine-18 fluorodeoxyglucose positron emission tomography/computed tomography ( 18 F-FDG PET/CT) is becoming more clinically significant in the management of patients with PC. A 60-year-old male presented with nonsmall cell lung cancer (NSCLC) and later showed signs of peritoneal disease on 18 F-FDG PET/CT imaging, which subsequently lead to the diagnoses of PC with histopathology from peritoneal biopsy. The patient showed an excellent initial response to their NSCLC treatment but later presented with PC that was shown by FDG-avid ascites and a soft tissue mass in the pelvic area. The abdominal-pelvic lesions were confirmed cytologically to be peritoneal metastatic disease. 18 F-FDG PET/CT demonstrated value in preoperatively directing biopsy for diagnosing PC in this case of NSCLC. Further, 18 F-FDG PET/CT was useful in the monitoring of disease progression and thus influenced management in this case of NSCLC with PC, which is often challenging to detect and manage.

Is Hyperthermic Intraperitoneal Chemotherapy Appropriate for Colon Cancer?

Colorectal cancer (CRC) with peritoneal metastases is a complex disease and its management presents significant clinical challenges. In well-selected patients at experienced centers, CRS/hyperthermic intraperitoneal chemotherapy (HIPEC) can be performed with acceptable morbidity and is associated with prolonged survival. Based on the results of recent randomized controlled trials, HIPEC using oxaliplatin after CRS with shortened perfusion periods (30 minutes) is no longer recommended. There is a movement toward utilizing mitomycin C as a first-line intraperitoneal agent with extended perfusion times (90-120 minutes); however, there is currently little prospective evidence to support its widespread use.

Diagnostic Challenges for Clinicians in Lobular Breast Carcinoma With Peritoneal Carcinomatosis: A Case Report of an Immunocompromised Patient.

Peritoneal carcinomatosis (PC) is a common condition in oncology. The lack of specificity in radiological and clinical characteristics of carcinomatosis makes their etiological diagnosis difficult. Metastatic infiltrating lobular breast cancer with PC is also a common occurrence in daily medical practice. We report the case of a 45-year-old female patient with chronic renal failure undergoing hemodialysis, admitted for lobular breast carcinoma with bone and peritoneal metastases. The surgical exploration including a biopsy revealed peritoneal tuberculosis. The focus of this paper is to discuss the diagnostic traps associated with PC in malignant tumors to highlight the importance of pathological evidence in such cases.

New insights in the management of pseudomyxoma peritonei.

While a rare entity, peritoneal pseudomyxoma treatment evolves. Decision-making criteria improve with imaging development and exploratory laparoscopy. Surgery remains at the core of the therapeutic strategy whatever disease progression. Complete cytoreduction plus hyperthermic intraperitoneal chemotherapy (HIPEC) is standard of care. Iterative cytoreduction or debulking is sometimes justified. Intraperitoneal chemotherapy modalities change with early postoperative HIPEC or pressurized intraperitoneal aerosol chemotherapy. Systemic or local treatment such as new chemo/immuno-therapies or BromAc should improve outcomes. Expertise and multicentric cooperation are more than ever needed.

Gastric adenocarcinoma with carcinomatosis and degenerative joint disease of the xiphisternum in a Bactrian camel (Camelus bactrianus).

Gastric adenocarcinomas have been sporadically reported in camelids. This report describes a primary gastric adenocarcinoma and subsequent peritoneal carcinomatosis in a 20-year-old female Bactrian camel (Camelus bactrianus). Numerous metastases were present throughout the omentum, liver, abdominal lymph nodes, intestinal serosa, kidneys and lungs. The primary tumour macroscopically resembled an ulcerated crater and originated from the distal four-fifths of the C3 compartment, an anatomical region with naturally prominent gastric rugae and true glands. Moderate numbers of Helicobacter spp colonies were present within gastric pits and necrotic areas of C3. Ménetrier's disease has previously been implicated as a predisposing condition for the development of gastric adenocarcinoma in another camel, but no evidence of this premalignant disorder was found in this case. This camel also suffered from a chronic skin wound of the hump and severe degenerative joint disease of the xiphisternum, the latter of which was presumably associated with excessive pressure on the sternum.

Sacituzumab govitecan response in extensive leptomeningeal carcinomatosis from triple-negative breast cancer: a case report.

Sacituzumab govitecan (SG), a Trop-2-directed antibody-drug conjugate (ADC), was the first ADC approved for patients with metastatic triple-negative breast cancer (mTNBC) who had received at least two prior lines of therapy for advanced disease. Although SG has shown promising clinical activity in treating brain metastases in both ASCENT randomized trials and real-world analysis, its utility in leptomeningeal carcinomatosis (LC) remains underexplored. We report the diagnostic and therapeutic process of a patient who develops extensive LC from TNBC treated with SG. She presented a clinical response after the first cycle of SG with a PFS of 6 months. This case report highlights the need for further inquiry into the use of SG in LC.

Tyrosine kinase inhibitors in the treatment of leptomeningeal carcinomatosis.

Leptomeningeal carcinomatosis (LMC) is a devastating complication of advanced cancers, such as lung cancer and breast cancer, which is usually indicative of a poor prognosis. The current treatments for LMC include palliative care, with others aiming to prolong survival and relieve neurological symptoms. Traditional treatments for LMC include radiotherapy, systemic chemotherapy, and intrathecal injection. Furthermore, the application of molecularly targeted agents, such as antiepidermal growth factor receptor (anti-EGFR), antihuman epidermal growth factor receptor 2 (anti-HER2), and anti-PD-1 monoclonal antibody, have prolonged the survival of LMC patients. Targeted therapy with tyrosine kinase inhibitors has also been proven to be an effective treatment. Tyrosine kinases can be overactive or expressed at high levels in some cancer cells; therefore, the use of tyrosine kinase inhibitors may prevent the activation of tumor-related pathways, preventing cancer cell growth. The EGFR family are cell surface receptors directly related to tumor occurrence with tyrosine kinase activity; it is the most widely used target for tyrosine kinase inhibitors in the treatment of LMC. In this review, we introduced the clinical manifestation and diagnostic criteria of LMC, clarified the treatment mechanism of tyrosine kinase inhibitors for LMC with mutations in EGFR, HER2, or anaplastic lymphoma kinase, reviewed the current application of various generation tyrosine kinase inhibitors in patients with LMC, and discussed new clinical trials and the future directions of tyrosine kinase inhibitor therapy.

Disseminated Carcinomatosis of the Bone Marrow from Castration-Resistant Prostate Cancer Revealed by Choline Positron Emission Tomography-Computed Tomography.

Introduction: Disseminated carcinomatosis of the bone marrow is caused by cancer metastasis to the bone marrow and is the diagnosis is very difficult by imaging. Case Presentation: We report a 75-year-old male with disseminated carcinomatosis of the bone marrow from castration-resistant prostate cancer revealed by 11C-choline positron emission tomography-computed tomography (PET/CT). Although he already received radiotherapy to the prostate, combined androgen blockade, enzalutamide and apalutamide, and external beam radiotherapy for the pelvic bone metastases, serum prostate-specific antigen (PSA) value rapidly increased from 32 ng/mL to 104 ng/mL in recent 1 month. Bone scintigraphy showed almost no abnormal uptake in the whole body, whereas 11C-choline PET/CT showed diffuse bone marrow 11C-choline uptake. The disseminated carcinomatosis of the bone marrow was diagnosed from the discordant findings between bone scintigraphy and 11C-choline PET/CT examinations and confirmed pathologically by iliac marrow biopsy pathologically. Although docetaxel therapy was started, PSA value continued rising and he died after 4 months of the diagnosis. Conclusion: The discordant findings of choline PET/CT and bone scintigraphy can diagnose disseminated carcinomatosis of the bone marrow from prostate cancer.

Intraperitoneal drug delivery systems for peritoneal carcinomatosis: Bridging the gap between research and clinical implementation.

Several abdominal-located cancers develop metastasis within the peritoneum, what is called peritoneal carcinomatosis (PC), constituting a clinical challenge in their therapeutical management, often leading to poor prognoses. Current multidisciplinary strategies, including cytoreductive surgery (CRS), hyperthermic intraperitoneal chemotherapy (HIPEC), and pressurized intraperitoneal aerosol chemotherapy (PIPAC), demonstrate efficacy but have limitations. In response, alternative strategies are explored in the drug delivery field for intraperitoneal chemotherapy. Controlled drug delivery offers a promising avenue, maintaining localized drug concentrations for optimal PC management. Drug delivery systems (DDS), including hydrogels, implants, nanoparticles, and hybrid systems, show potential for sustained and region-specific drug release. The present review aims to offer an overview of the advances and current designs of DDS for PC chemotherapy administration, focusing on their composition, main characteristics, and principal experimental outcomes, highlighting the importance of biomaterial rationale design and in vitro/vivo models for their testing. Moreover, since clinical data for human subjects are scarce, we offer a critical discussion of the gap between bench and bedside in DDS translation, emphasizing the need for further research.

Efficacy of Hyperthermic Pressurized Intraperitoneal Aerosol Chemotherapy in an In Vitro Model Using a Human Gastric Cancer AGS Cell Line and an Abdominal Cavity Model.

PURPOSE: Peritoneal carcinomatosis (PC) presents a major challenge in the treatment of late-stage, solid tumors, with traditional therapies limited by poor drug penetration. We evaluated a novel hyperthermic pressurized intraperitoneal aerosol chemotherapy (HPIPAC) system using a human abdominal cavity model for its efficacy against AGS gastric cancer cells. MATERIALS AND METHODS: A model simulating the human abdominal cavity and AGS gastric cancer cell line cultured dishes were used to assess the efficacy of the HPIPAC system. Cell viability was measured to evaluate the impact of HPIPAC under 6 different conditions: heat alone, PIPAC with paclitaxel (PTX), PTX alone, normal saline (NS) alone, heat with NS, and HPIPAC with PTX. RESULTS: Results showed a significant reduction in cell viability with HPIPAC combined with PTX, indicating enhanced cytotoxic effects. Immediately after treatment, the average cell viability was 66.6%, which decreased to 49.2% after 48 hours and to a further 19.6% after 120 hours of incubation, demonstrating the sustained efficacy of the treatment. In contrast, control groups exhibited a recovery in cell viability; heat alone showed cell viability increasing from 90.8% to 94.4%, PIPAC with PTX from 82.7% to 89.7%, PTX only from 73.3% to 74.8%, NS only from 90.9% to 98.3%, and heat with NS from 74.4% to 84.7%. CONCLUSIONS: The HPIPAC system with PTX exhibits a promising approach in the treatment of PC in gastric cancer, significantly reducing cell viability. Despite certain limitations, this study highlights the system's potential to enhance treatment outcomes. Future efforts should focus on refining HPIPAC and validating its effectiveness in clinical settings.

Primary Peritoneal Mesothelioma Affecting the Greater Omentum That Mimicked an Omental Infarction: A Case Report.

Introduction: Malignant peritoneal mesothelioma (MPM) is a rare cancer that is associated with asbestos exposure. The diagnosis can be difficult given the nonspecific nature of presenting symptoms and the presence of concomitant confounding findings. Case Presentation: We report a 71-year-old male who presented with right lower quadrant pain and new-onset ascites. CT imaging of the abdomen/pelvis demonstrated omental stranding concerning for a possible omental infarction. Subsequent imaging showed persistent omental edema but no identifiable soft tissue mass. A biopsy of the omentum showed atypical mesothelial proliferation, but pathology was unable to determine if proliferation was a neoplastic versus reactive process. Surgical oncology performed a diagnostic laparoscopy that showed peritoneal studding of the omentum. Subsequent immunohistochemical staining of the omentum demonstrated preservation of BAP1 expression and loss of MTAP expression, consistent with peritoneal mesothelioma. Conclusion: MPM is a rare and aggressive cancer with an overall poor prognosis. The diagnosis of MPM can be difficult based on the nonspecific clinical presentation, insufficient imaging and laboratory testing, and the presence of concomitant confounding findings, such as with this patient and his admitting diagnosis of omental infarction. This case demonstrates the importance of developing a broad differential while maintaining an awareness of heuristics that can influence clinical decision-making.

Home-Based Trimodal Prehabilitation in Patients with Peritoneal Carcinomatosis Undergoing Cytoreductive Surgery: Effect on Functional Walking Capacity and Skeletal Muscle Mass.

BACKGROUND: Patients with peritoneal carcinomatosis often suffer from loss of skeletal muscle mass and require extensive surgery. Multimodal prehabilitation may improve physical status but its benefits for these specific patients remain unknown. This study aimed to evaluate the effect of prehabilitation on functional walking capacity and skeletal muscle mass, as well as its association with postoperative complications. PATIENTS AND METHODS: A prospective study of patients with peritoneal carcinomatosis following a home-based trimodal prehabilitation program was carried out. Functional walking capacity was assessed with the 6-min walk test (T6MWT), and by the appendicular skeletal muscle index (ASMI) estimated by bioelectrical impedance analysis. Data were collected at the first medical appointment and on the day before surgery. A 90-day postoperative morbidity was registered according to the Clavien-Dindo classification. RESULTS: A total of 62 patients were included in the analysis. Women were more prevalent (77.4%) and peritoneal metastasis from ovarian origin accounted for 48.4%. Clavien II-V grades occurred in 30 (57.7%) patients. After prehabilitation, functional walking capacity improved by 42.2 m (39.62-44.72 m) compared with baseline data (p < 0.001), but no improvement was observed in the ASMI (p = 0.301). Patients able to walk at least 360 m after prehabilitation suffered fewer Clavien-Dindo II-V postoperative complications (p = 0.016). A T6MWT of less than 360 m was identified as an independent risk factor in the multivariable analysis (OR 3.99; 1.01-15.79 p = 0.048). CONCLUSIONS: This home-based trimodal prehabilitation program improved functional walking capacity but not ASMI scores in patients with peritoneal metastasis before surgery. A T6MWT of less than 360 m was found to be a risk factor for postoperative complications.

Systematic Cholecystectomy During Cytoreductive Surgery Plus HIPEC: A Critical Analysis of an Empirical Tradition.

BACKGROUND: Some procedures performed during cytoreductive surgery (CRS) and hyperthermic intraoperative intraperitoneal chemotherapy (HIPEC) are based on empirical data. One of these procedures is systematic cholecystectomy. This study aimed to perform a critical analysis of the need for systematic cholecystectomy during CRS+HIPEC of patients with peritoneal carcinomatosis using long-term follow-up data. METHODS: Patients with peritoneal surface malignancies who were candidates for CRS+HIPEC and underwent surgery between January 2008 and December 2022 were analyzed. For patients with gallbladder involvement due to the disease or for patients whose preoperative study showed the presence of cholelithiasis, cholecystectomy was performed as part of the surgery, which was avoided for the remaining patients. All postoperative adverse events that occurred in the first 90 days were recorded, and clinical records focused on the development of biliary pathology during the follow-up period were studied. RESULTS: The results from a consecutive series of 443 patients with peritoneal surface malignancies who underwent surgery between January 2008 and December 2022 were analyzed. The average age of the cohort was 50 years. The median follow-up period for the cohort was 41 months (range, 12-180 months), with a disease-free survival of 17 months. For 373 of the patients, CRS+HIPEC was completed without an associated cholecystectomy, and in 16 of them, the appearance of cholelithiasis was detected during the follow-up period. Only two patients in the series showed complications derived from gallstones and required a delayed cholecystectomy. CONCLUSIONS: Although cholecystectomy is a safe procedure in the context of CRS+HIPEC, it is not risk free, and its routine performance may be unnecessary.

Enhancing precision in colorectal cancer surgery: development of an LGR5-targeting RSPO1 peptide mimetic as a contrast agent for intraoperative fluorescence molecular imaging.

Colorectal cancer (CRC) is the third most common cancer worldwide. In the United States alone, CRC was responsible for approximately 52,550 deaths in 2023, with an estimated 153,020 new cases. CRC presents with synchronous peritoneal spread in 5-10% of patients, and up to 20-50% of patients with recurrent disease will develop metachronous colorectal cancer peritoneal metastatic (CRC-PM) disease. Eradication of the tumor, tumor margins and microscopic residual disease is paramount, as microscopic residual disease is associated with local recurrences, with 5-year survival rates of less than 35%. The success of resection and reduction of residual disease depends on the accuracy with which cancer cells and normal tissue can be intra-operatively distinguished. Fluorescence Molecular Imaging (IFMI) and tumor-targeted contrast agents represent a promising approach for intraoperative detection and surgical intervention. Proper target selection, the development of scalable imaging agents and enhanced real-time tumor and tumor microenvironment imaging are critical to enabling enhanced surgical resection. LGR5 (leucine-rich repeat-containing G-protein-coupled receptor 5), a colonic crypt stem cell marker and the receptor for the R-spondins (RSPO) in the Wnt signaling pathway, is also expressed on colorectal cancer stem cells (CSC) and on CRC tumors and metastases, suggesting it could be a useful target for imaging of CRC. However, there are numerous diverging reports on the role of LGR5 in CRC therapy and outcomes. Herein, we report on the synthesis and validation of a 37 amino acid RSPO1-mimetic peptide, termed RC18, that was specifically designed to access the R-spondin binding site of LGR5 to potentially be used for interoperative imaging of CRC-PM. The receptor-binding capabilities of the RC18 indicate that direct interactions with LGR5 neither significantly increased LGR5 signaling nor blocked RSPO1 binding and signal transduction, suggesting that the RSPO1-mimetic is functionally inert, making it an attractive contrast agent for intraoperative CRC-PM imaging.

A non-enhancing, T2 fluid-attenuated inversion recovery hyperintense, diffusion-restricting brainstem lesion in an EGFR tyrosine kinase inhibitor-treated non-small-cell lung cancer patient.

Leptomeningeal metastasis (LM) is a devastating complication of malignancy. Diagnosis relies on both contrast enhancement on imaging and malignant cells in cerebral spinal fluid cytology. Though early detection and prompt intervention improves survival, the detection of LM is limited by false negatives. A rare brainstem imaging finding uncovered specifically in EGFR mutation-positive lung cancer patients may represent an early sign of LM. This sign demonstrates high signal on T2 fluid-attenuated inversion recovery and diffusion-weighted imaging sequences, but paradoxically lacks correlative contrast enhancement. Here we report a case of a 72-year-old female EGFR-positive lung cancer patient who developed this lesion following treatment with two first-generation EGFR tyrosine kinase inhibitors then showed subsequent response to osimertinib, an irreversible third-generation EGFR tyrosine kinase inhibitor.

A non-enhancing, T2 FLAIR hyperintense, diffusion-restricting brainstem lesion in an EGFR-positive lung cancer patient may represent an early indicator of leptomeningeal metastases.