Mitigating Illumination-, Leaf-, and View-Angle Dependencies in Hyperspectral Imaging Using Polarimetry.

Automation of plant phenotyping using data from high-dimensional imaging sensors is on the forefront of agricultural research for its potential to improve seasonal yield by monitoring crop health and accelerating breeding programs. A common challenge when capturing images in the field relates to the spectral reflection of sunlight (glare) from crop leaves that, at certain solar incidences and sensor viewing angles, presents unwanted signals. The research presented here involves the convergence of 2 parallel projects to develop a facile algorithm that can use polarization data to decouple light reflected from the surface of the leaves and light scattered from the leaf's tissue. The first project is a mast-mounted hyperspectral imaging polarimeter (HIP) that can image a maize field across multiple diurnal cycles throughout a growing season. The second project is a multistatic fiber-based Mueller matrix bidirectional reflectance distribution function (mmBRDF) instrument which measures the polarized light-scattering behavior of individual maize leaves. The mmBRDF data was fitted to an existing model, which outputs parameters that were used to run simulations. The simulated data were then used to train a shallow neural network which works by comparing unpolarized 2-band vegetation index (VI) with linearly polarized data from the low-reflectivity bands of the VI. Using GNDVI and red-edge reflection ratio we saw an improvement of an order of magnitude or more in the mean error (ϵ) and a reduction spanning 1.5 to 2.7 in their standard deviation (ϵσ) after applying the correction network on the HIP sensor data.

Mesenchymal Stem Cell Extracellular Vesicles as a New Treatment Paradigm in Solid Abdominal Organ Transplantation: A Case Series.

Solid abdominal organ transplantation is fraught with variable rates of rejection and graft versus host disease (GVHD). We sought to determine the safety and efficacy of an advanced extracellular vesicle (EV) investigational product (IP) derived from mesenchymal stem cells (MSC) in the transplant patient population. Seven separate emergency investigational new drug (eNIDs) were filed with the Food and Drug Administration (FDA) for the emergency treatment of rejection of an isolated intestinal graft (n = 2), liver allograft graft (n = 2), modified multivisceral graft (n = 3), and GVHD in isolated intestinal transplant patients (n = 2). Fifteen milliliters of IP was administered intravenously on Day 0, 2, 4, and this treatment cycle was repeated up to four times in each patient depending on the treatment protocol allowed by the FDA. Safety (adverse event reporting) and efficacy (clinical status, serologies, and histopathology) were evaluated. There were no adverse events related to IP. All patients had improvement in clinical symptoms within 24 h, improved serologic laboratory evaluation, improved pulmonary symptoms and dermatologic manifestations of GVHD, and complete histologic resolution of graft inflammation/rejection within 7 days of IP administration. Systemic use of a MSC-derived EV IP was successful in achieving histological clearance of intestinal, liver, and multivisceral graft inflammation, and skin and pulmonary manifestations of GVHD.

A novel murine model of pyoderma gangrenosum reveals that inflammatory skin-gut crosstalk is mediated by IL-1ß-primed neutrophils.

Pyoderma gangrenosum (PG) is a debilitating skin condition often accompanied by inflammatory bowel disease (IBD). Strikingly, ~40% of patients that present with PG have underlying IBD, suggesting shared but unknown mechanisms of pathogenesis. Impeding the development of effective treatments for PG is the absence of an animal model that exhibits features of both skin and gut manifestations. This study describes the development of the first experimental drug-induced mouse model of PG with concomitant intestinal inflammation. Topical application of pyrimidine synthesis inhibitors on wounded mouse skin generates skin ulcers enriched in neutrophil extracellular traps (NETs) as well as pro-inflammatory cellular and soluble mediators mimicking human PG. The mice also develop spontaneous intestinal inflammation demonstrated by histologic damage. Further investigations revealed increased circulating low density IL-1ß primed neutrophils that undergo enhanced NETosis at inflamed tissue sites supported by an increase in circulatory citrullinated histone 3, a marker of aberrant NET formation. Granulocyte depletion dampens the intestinal inflammation in this model, further supporting the notion that granulocytes contribute to the skin-gut crosstalk in PG mice. We anticipate that this novel murine PG model will enable researchers to probe common disease mechanisms and identify more effective targets for treatment for PG patients with IBD.

Hybrid spatial-temporal Mueller matrix imaging spectropolarimeter for high throughput plant phenotyping.

Many correlations exist between spectral reflectance or transmission with various phenotypic responses from plants. Of interest to us are metabolic characteristics, namely, how the various polarimetric components of plants may correlate to underlying environmental, metabolic, and genotypic differences among different varieties within a given species, as conducted during large field experimental trials. In this paper, we overview a portable Mueller matrix imaging spectropolarimeter, optimized for field use, by combining a temporal and spatial modulation scheme. Key aspects of the design include minimizing the measurement time while maximizing the signal-to-noise ratio by mitigating systematic error. This was achieved while maintaining an imaging capability across multiple measurement wavelengths, spanning the blue to near-infrared spectral region (405-730 nm). To this end, we present our optimization procedure, simulations, and calibration methods. Validation results, which were taken in redundant and non-redundant measurement configurations, indicated that the polarimeter provides average absolute errors of (5.3±2.2)×10-3 and (7.1±3.1)×10-3, respectively. Finally, we provide preliminary field data (depolarization, retardance, and diattenuation) to establish baselines of barren and non-barren Zea maize hybrids (G90 variety), as captured from various leaf and canopy positions during our summer 2022 field experiments. Results indicate that subtle variations in retardance and diattenuation versus leaf canopy position may be present before they are clearly visible in the spectral transmission.

Healthcare worker safety program in a coronavirus disease 2019 (COVID-19) alternate care site: The Javits New York Medical Station experience.

OBJECTIVE: In March 2020, New York City became the epicenter of the coronavirus disease 2019 (COVID-19) pandemic in the United States. Because healthcare facilities were overwhelmed with patients, the Jacob K. Javits Convention Center was transformed into the nation's largest alternate care site: Javits New York Medical Station (hereafter termed Javits). Protecting healthcare workers (HCWs) during a global shortage of personal protective equipment (PPE) in a nontraditional healthcare setting posed unique challenges. We describe components of the HCW safety program implemented at Javits. SETTING: Javits, a large convention center transformed into a field hospital, with clinical staff from the US Public Health Service Commissioned Corps and the US Department of Defense. METHODS: Key strategies to ensure HCW safety included ensuring 1-way flow of traffic on and off the patient floor, developing a matrix detailing PPE required for each work activity and location, PPE extended use and reuse protocols, personnel training, and monitoring adherence to PPE donning/doffing protocols when entering or exiting the patient floor. Javits staff who reported COVID-19 symptoms were immediately isolated, monitored, and offered a severe acute respiratory coronavirus virus 2 (SARS-CoV-2) reverse-transcriptase polymerase chain reaction (RT-PCR) test. CONCLUSIONS: A well-designed and implemented HCW safety plan can minimize the risk of SARS-CoV-2 infection for HCWs. The lessons learned from operating the nation's largest COVID-19 alternate care site can be adapted to other environments during public health emergencies.

Modern trends in minimally invasive versus open hepatectomy for colorectal liver metastasis: an analysis of ACS-NSQIP.

BACKGROUND: Surgical resection of colorectal liver metastasis (CRLM) provides the best opportunity for prolonged survival. Eligibility for metastasectomy has expanded with technical advancements including parenchymal-sparing hepatectomy (PSH). Meanwhile, enthusiasm for minimally invasive surgery (MIS) has increased, though this approach may be preferentially utilized for technically straightforward cases. The purpose of this study is to characterize modern trends in open versus MIS approaches to partial hepatectomy and anatomic hepatectomy for CRLM within a nationwide cohort. METHODS: The American College of Surgeons' National Surgical Quality Improvement Program (ACS-NSQIP) was used to investigate trends in MIS versus open hepatectomy for CRLM from 2015 to 2019. We examined baseline clinicopathologic and disease-related characteristics and compared trends in treatments over the study period. RESULTS: A total of 7457 patients undergoing hepatectomy for CRLM were identified (1367 MIS, 6090 open). Patients had similar clinicopathologic features between the two groups. Patients undergoing MIS resection less frequently received neoadjuvant therapy (51.1% vs 64.0%, p < 0.001) or concurrent intraoperative ablation (15.0% vs 21.3%, p < 0.001). Patients with tumors < 2 cm (34.9% vs 26.8%, p < 0.001) or only one to two tumors (82.8% vs 65.0%, p < 0.001) more commonly underwent MIS. MIS and open partial hepatectomies both significantly increased over the study period, but open partial hepatectomy increased at a greater rate than MIS (p < 0.001). Rates of anatomic resections have remained the same, with a greater proportion performed using an open approach (34.9% vs 16.4%, p < 0.001). Rates of operations consisting of > 1 concurrent partial hepatectomy are stable, but significantly more likely to be performed open (p < 0.001). CONCLUSIONS: Hepatectomy for CRLM has increased from a rise in partial hepatectomy, potentially translating to increased use of PSH. Current trends suggest MIS approaches appear to be increasing, but selectively implemented for patients with less technically demanding disease characteristics. Educational efforts should be directed towards increased dissemination of parenchymal-sparing MIS techniques for more complex resections.

Human hepatocyte PNPLA3-148M exacerbates rapid non-alcoholic fatty liver disease development in chimeric mice.

Advanced non-alcoholic fatty liver disease (NAFLD) is a rapidly emerging global health problem associated with pre-disposing genetic polymorphisms, most strikingly an isoleucine to methionine substitution in patatin-like phospholipase domain-containing protein 3 (PNPLA3-I148M). Here, we study how human hepatocytes with PNPLA3 148I and 148M variants engrafted in the livers of broadly immunodeficient chimeric mice respond to hypercaloric diets. As early as four weeks, mice developed dyslipidemia, impaired glucose tolerance, and steatosis with ballooning degeneration selectively in the human graft, followed by pericellular fibrosis after eight weeks of hypercaloric feeding. Hepatocytes with the PNPLA3-148M variant, either from a homozygous 148M donor or overexpressed in a 148I donor background, developed microvesicular and severe steatosis with frequent ballooning degeneration, resulting in more active steatohepatitis than 148I hepatocytes. We conclude that PNPLA3-148M in human hepatocytes exacerbates NAFLD. These models will facilitate mechanistic studies into human genetic variant contributions to advanced fatty liver diseases.

Epstein-Barr virus-associated smooth muscle tumors in immunocompromised patients: Six case reports.

BACKGROUND: Epstein-Barr virus associated smooth muscle tumor (EBV-SMT) is a rare oncological entity. However, there is an increasing incidence of EBV-SMTs, as the frequency of organ transplantation and immunosuppression grows. EBV-SMT diagnosis relies on histopathology and immunochemical staining to distinguish it from post-transplant lymphoproliferative disorder (PTLD). There is no clear consensus on the treatment of EBV-SMTs. However, surgical resection, chemotherapy, radiation therapy, and immunosuppression reduction have been explored with varying degrees of success. CASE SUMMARY: Our case series includes six cases of EBV-SMTs across different age groups, with different treatment modalities, adding to the limited existing literature on this rare tumor. The median latency time between immunosuppression and disease diagnosis is four years. EBV-SMTs present with variable degrees of aggressiveness and seem to have worse clinical outcomes in patients with tumor multiplicity and worse immunocompetency. CONCLUSION: It is imperative to continue building on this knowledge and keeping EBV-SMTs on the differential in immunocompromised individuals.

Bacterial Vaginosis Monitoring with Carbon Nanotube Field-Effect Transistors.

The ability to rapidly and reliably screen for bacterial vaginosis (BV) during pregnancy is of great significance for maternal health and pregnancy outcomes. In this proof-of-concept study, we demonstrated the potential of carbon nanotube field-effect transistors (NTFET) in the rapid diagnostics of BV with the sensing of BV-related factors such as pH and biogenic amines. The fabricated sensors showed good linearity to pH changes with a linear correlation coefficient of 0.99. The pH sensing performance was stable after more than one month of sensor storage. In addition, the sensor was able to classify BV-related biogenic amine-negative/positive samples with machine learning, utilizing different test strategies and algorithms, including linear discriminant analysis (LDA), support vector machine (SVM), and principal component analysis (PCA). The biogenic amine sample status could be well classified using a soft-margin SVM model with a validation accuracy of 87.5%. The accuracy could be further improved using a gold gate electrode for measurement, with accuracy higher than 90% in both LDA and SVM models. We also explored the sensing mechanisms and found that the change in NTFET off current was crucial for classification. The fabricated sensors successfully detect BV-related factors, demonstrating the competitive advantage of NTFET for point-of-care diagnostics of BV.

Multistatic fiber-based system for measuring the Mueller matrix bidirectional reflectance distribution function.

Bidirectionality effects can be a significant confounding factor when measuring hyperspectral reflectance data. The bidirectional reflectance distribution function (BRDF) can effectively characterize the reflectivity of surfaces to correct remote sensing measurements. However, measuring BRDFs can be time-consuming, especially when collecting Mueller matrix BRDF (mmBRDF) measurements of a surface via conventional goniometric techniques. In this paper, we present a system for collecting mmBRDF measurements using static optical fiber detectors that sample the hemisphere surrounding an object. The entrance to each fiber contains a polarization state analyzer configuration, allowing for the simultaneous acquisition of the Stokes vector intensity components at many altitudinal and azimuthal viewing positions. We describe the setup, calibration, and data processing used for this system and present its performance as applied to mmBRDF measurements of a ground glass diffuser.

Using the Flipped Classroom Model in Surgical Education: Efficacy and Trainee Perception.

OBJECTIVE: To describe the feasibility, efficacy, and learner perception of the flipped classroom model for teaching conferences within surgical training programs. DESIGN: For the flipped classroom conferences, video lectures were prepared by a faculty member, and sent to all attendees at least 2 days prior to lecture. The conference time was then spent going over cases and questions, rather than traditional lecture. We conducted a qualitative survey to assess learner's perceptions and pre-lecture quizzes to assess trainee preparedness. SETTING: The comparison of pre-conference quizzes between flipped classroom and traditional models was carried out at Brooke Army Medical Center (BAMC) in San Antonio, TX, a tertiary care facility with a general surgery residency program. The survey was conducted at BAMC and within the Complex General Surgical Oncology fellowship program at University of Texas MD Anderson Cancer Center, where a flipped classroom model was similarly employed. PARTICIPANTS: Surgical residents BAMC participated in pre-lecture quizzes. BAMC residents and MD Anderson fellows were invited to complete the online survey. RESULTS: Lecture videos did not increase mean preparation time (1.53 vs. 1.46 hours without vs. with video, p = 0.858), but did increase mean quiz scores from 67% to 80% (p = 0.031) with 32/35 learners utilizing videos. Videos increased the proportion of learners who self-reported preparing at all from 42% to 95% (p = 0.28), and preparing for at least one hour for conference from 23% to 49% (p = 0.014). Of survey respondents, 90% said videos were very helpful, 90% would use them weekly if available, and 90% prefer this format to traditional lecture. CONCLUSIONS: Utilization of a flipped classroom method was well received and preferred by surgical trainees, and it increased performance on pre-conference quizzes without increasing preparation time. Although creation of video lectures is work-intensive for lecturers, these results suggest it is more effective for learner preparation. These results could be generalizable to surgical residents nationwide as technology utilization increases in surgical education.

Crohn Disease Infrequently Affects the Appendix and Rarely Causes Granulomatous Appendicitis.

Data from previous studies suggest Crohn disease of the appendix accounts for ∼25% of granulomatous appendicitis cases. However, we have found that granulomatous inflammation in appendectomy specimens rarely heralds Crohn disease. We suspect that appendiceal involvement by Crohn disease is uncommon, even when patients have severe ileocolonic inflammation. We performed this study to determine the prevalence and nature of appendiceal inflammation among patients with Crohn disease. We reviewed 100 ileocolic specimens with strictures and fistulizing Crohn disease for the nature and distribution of inflammatory changes in the appendix and compared them with 100 appendices on colectomy specimens from age-matched and sex-matched patients with ulcerative colitis. We also evaluated 27 additional cases of granulomatous appendicitis in appendectomy specimens to determine the frequency with which this finding represented Crohn disease. The appendix was usually normal (26%) or showed fibrous obliteration (50%) in ileocolic resection specimens from patients with Crohn disease. Mucosal inflammation was much less common in appendices from patients with Crohn disease than ulcerative colitis (6% vs. 28%, P<0.0001); only 4 cases contained epithelioid granulomata, 3 showed mural fibrosis and lymphoid aggregates, and 10 displayed only periappendiceal inflammation. None of the patients with granulomatous appendicitis in appendectomy specimens had, or developed, evidence of Crohn disease. We conclude that Crohn disease infrequently affects the appendix. Interval appendectomy and infection are more important considerations when appendectomy specimens feature granulomatous inflammation and/or mural lymphoid aggregates, especially if there is no history of idiopathic inflammatory bowel disease.

Quantification of gray mold infection in lettuce using a bispectral imaging system under laboratory conditions.

Gray mold disease caused by the fungus Botrytis cinerea damages many crop hosts worldwide and is responsible for heavy economic losses. Early diagnosis and detection of the disease would allow for more effective crop management practices to prevent outbreaks in field or greenhouse settings. Furthermore, having a simple, non-invasive way to quantify the extent of gray mold disease is important for plant pathologists interested in measuring infection rates. In this paper, we design and build a bispectral imaging system for discriminating between leaf regions infected with gray mold and those that remain unharmed on a lettuce (Lactuca spp.) host. First, we describe a method to select two optimal (high contrast) spectral bands from continuous hyperspectral imagery (450-800 nm). We then explain the process of building a system based on these two spectral bands, located at 540 and 670 nm. The resultant system uses two cameras, with a narrow band-pass spectral filter mounted on each, to measure the bispectral reflectance of a lettuce leaf. The two resulting images are combined using a normalized difference calculation that produces a single image with high contrast between the leaves' infected and healthy regions. A classifier was then created based on the thresholding of single pixel values. We demonstrate that this simple classification produces a true-positive rate of 95.25% with a false-positive rate of 9.316% in laboratory conditions.

Antigen-based multiplex strategies to discriminate SARS-CoV-2 natural and vaccine induced immunity from seasonal human coronavirus humoral responses.

Sensitive and specific SARS-CoV-2 antibody assays remain critical for community and hospital-based SARS-CoV-2 sero-surveillance. With the rollout of SARS-CoV-2 vaccines, such assays must be able to distinguish vaccine from natural immunity to SARS-CoV-2 and related human coronaviruses. Here, we developed and implemented multiplex microsphere-based immunoassay strategies for COVD-19 antibody studies that incorporates spike protein trimers of SARS-CoV-2 and the endemic seasonal human coronaviruses (HCoV), enabling high throughout measurement of pre-existing cross-reactive antibodies. We varied SARS-CoV-2 antigen compositions within the multiplex assay, allowing direct comparisons of the effects of spike protein, receptor-binding domain protein (RBD) and nucleocapsid protein (NP) based SARS-CoV-2 antibody detection. Multiplex immunoassay performance characteristics are antigen-dependent, and sensitivities and specificities range 92-99% and 94-100%, respectively, for human subject samples collected as early as 7-10 days from symptom onset. SARS-CoV-2 spike and RBD had a strong correlative relationship for the detection of IgG. Correlation between detectable IgG reactive with spike and NP also had strong relationship, however, several PCR-positive and spike IgG-positive serum samples were NP IgG-negative. This spike and NP multiplex immunoassay has the potential to be useful for differentiation between vaccination and natural infection induced antibody responses. We also assessed the induction of de novo SARS-CoV-2 IgG cross reactions with SARS-CoV and MERS-CoV spike proteins. Furthermore, multiplex immunoassays that incorporate spike proteins of SARS-CoV-2 and HCoVs will permit investigations into the influence of HCoV antibodies on COVID-19 clinical outcomes and SARS-CoV-2 antibody durability.

Internal defect scanning of sweetpotatoes using interactance spectroscopy.

While standard visible-light imaging offers a fast and inexpensive means of quality analysis of horticultural products, it is generally limited to measuring superficial (surface) defects. Using light at longer (near-infrared) or shorter (X-ray) wavelengths enables the detection of superficial tissue bruising and density defects, respectively; however, it does not enable the optical absorption and scattering properties of sub-dermal tissue to be quantified. This paper applies visible and near-infrared interactance spectroscopy to detect internal necrosis in sweetpotatoes and develops a Zemax scattering simulation that models the measured optical signatures for both healthy and necrotic tissue. This study demonstrates that interactance spectroscopy can detect the unique near-infrared optical signatures of necrotic tissues in sweetpotatoes down to a depth of approximately 5±0.5 mm. We anticipate that light scattering measurement methods will represent a significant improvement over the current destructive analysis methods used to assay for internal defects in sweetpotatoes.

Rates, Predictors, and Outcomes of Portal Lymphadenectomy for Resectable Gallbladder Cancer.

INTRODUCTION: Lymphadenectomy (LND) is recommended following surgical resection of ≥ T1b gallbladder cancer (GBC). However, frequency and stage-specific survival benefits of LND remain unclear. PATIENTS AND METHODS: The National Cancer Database (NCDB; 2006-15) was queried for resected pathologic stage I-III GBC. LND performance, predictors of receiving LND, and LND association with overall survival (OS) were assessed. RESULTS: Of 2302 total patients, 1343 (58.3%) underwent LND. Patients who underwent LND were younger and more frequently had private health insurance, a negative surgical margin, higher pathologic T stage, and received adjuvant chemotherapy (all p < 0.001). LND rates were highest at academic centers (70.1%) relative to all other facility types (p < 0.001). LND was independently associated with improved OS [hazard ratio (HR) 0.52, 95% confidence interval (CI) 0.44-0.61]. LND was associated with improved OS for pT1b, pT2, and pT3 patients (all p < 0.05) on univariate analysis. LND was independently associated with improved OS in pT2 (HR 0.44, CI 0.35-0.56) and pT3 (HR 0.54, CI 0.43-0.69) patients. CONCLUSIONS: LND is associated with a 48% reduction in risk of death in patients with resectable non-metastatic GBC, with greatest impact in pT2-3 patients. Patients without LND have similar OS to patients with node-positive disease, highlighting the importance of LND. Underutilization of LND likely results in undertreatment of patients with undiagnosed nodal disease, which may contribute to unfavorable oncologic outcomes.

Subgroup analysis of nelipepimut-S plus GM-CSF combined with trastuzumab versus trastuzumab alone to prevent recurrences in patients with high-risk, HER2 low-expressing breast cancer.

HER2-targeted therapy has not benefited patients with low levels of HER2 expression; however, combination therapy may be effective. Primary analysis of a phase IIb trial investigating the HER2-derived vaccine nelipepimut-S (NPS) did not benefit the intention-to-treat population, but subset analysis showed a benefit in triple-negative breast cancer (TNBC) patients. The subset analysis of this multicenter, randomized, single-blind, phase IIb trial identified significant improvement in 36-month disease-free survival (DFS) between NPS (n = 55) and placebo (n = 44) in TNBC (HR 0.25, p = 0.01) and those who express HLA-A24 (HR 0.41, p = 0.05). The TNBC cohort demonstrated improved 36-month DFS in those with HER2 1+ expression (HR 0.17, p = 0.01), HLA-A24 positivity (HR 0.08, p < 0.01), or in those who received neoadjuvant chemotherapy (HR 0.21, p < 0.01). NPS vaccination with trastuzumab was associated with improved 36-month DFS among patients with TNBC. The observed benefit to this high-risk subgroup warrants confirmation in a phase III trial.

Lymph node sampling in resectable hepatocellular carcinoma: national practice patterns and predictors of positive lymph nodes.

BACKGROUND AND OBJECTIVES: Routine lymphadenectomy (LND) for resectable hepatocellular carcinoma (HCC) remains controversial. We evaluated national LND trends to identify pre-operative factors associated with node-positive disease to determine which patients might benefit from LND. METHODS: We identified HCC patients in the National Cancer Database (NCDB) treated with surgical resection between 2004 and 2015. Demographic, operative, pathologic, and survival data were compared. Multivariable regression was performed to determine preoperative predictors of pathologic nodal disease. RESULTS: Of 8095 total resected patients, 1442 (17.8%) underwent hepatectomy with LND. Patients who received LND had higher preoperative clinical T (T3-T4: 20.0% vs 12.1%, p < 0.001) and N (N1: 3.3% vs 0.6%, p < 0.001) stages. The strongest independent predictor of pathologic nodal disease was clinical N stage (OR 106.54, CI 44.10-257.42). Survival was highest in patients whose surgeons omitted LND or were found with LND to be node-negative on final pathology (p < 0.001). Clinical node positivity had high negative predictive value (97.9%) but moderate positive predictive value (56.3%) in estimating pathologic nodal status. CONCLUSIONS: Defining preoperative clinical nodal status is imperative in HCC patients. Clinical node positivity was the strongest predictor of pathologic nodal disease and its associated worse prognosis. LND can be considered selectively in clinically node-positive patients.

Chemoprevention in familial adenomatous polyposis: past, present and future.

Familial adenomatous polyposis (FAP) is a hereditary colorectal cancer syndrome characterized by colorectal adenomas and a near 100% lifetime risk of colorectal cancer (CRC). Prophylactic colectomy, usually by age 40, is the gold-standard therapy to mitigate this risk. However, colectomy is associated with morbidity and fails to prevent extra-colonic disease manifestations, including gastric polyposis, duodenal polyposis and cancer, thyroid cancer, and desmoid disease. Substantial research has investigated chemoprevention medications in an aim to prevent disease progression, postponing the need for colectomy and temporizing the development of extracolonic disease. An ideal chemoprevention agent should have a biologically plausible mechanism of action, be safe and easily tolerated over a prolonged treatment period, and produce a durable and clinically meaningful effect. To date, no chemoprevention agent tested has fulfilled these criteria. New agents targeting novel pathways in FAP are needed. Substantial preclinical literature exists linking the molecular target of rapamycin (mTOR) pathway to FAP. A single case report of rapamycin, an mTOR inhibitor, used as chemoprevention in FAP patients exists, but no formal clinical studies have been conducted. Here, we review the prior literature on chemoprevention in FAP, discuss the rationale for rapamycin in FAP, and outline a proposed clinical trial testing rapamycin as a chemoprevention agent in patients with FAP.