Surveillance Biopsies Research Articles

The Progression of Interstitial Fibrosis and Tubular Atrophy at 6 Months Is an Independent Predictor of Poor Graft Outcomes in Kidney Transplant Recipients.

We studied implantation and 6-mo surveillance biopsies and examined the association between the progression of IFTA (ΔIFTA) and a composite of censored graft loss or doubling of serum creatinine in 248 adult kidney recipients. The percentage of patients with ΔIFTA of 1 or ≥2 was 35% and 22%, respectively. Positive ΔIFTA was a risk factor for the composite endpoint (hazard ratio, 1.36; 95% confidence interval, 1.03-1.79). This estimate was robust to adjustment for recipient and donor baseline characteristics, baseline IFTA, tacrolimus levels, and rejection status. ΔIFTA was associated with decreased estimated glomerular filtration rate at 3 and 5 y. IFTA+i was a predictor in the cohort; however, IFTA progression was not limited to those with a mononuclear cell interstitial inflammation (Banff "i") score above zero. Notably, donor age was a predictor of IFTA at 6 mo, but not of ΔIFTA, whereas rejection, donor diabetes, and recipient smoking status were. Progression of IFTA at 6 mo can predict outcomes. ΔIFTA was not related to donor age but may be linked to other risk factors influencing decision-making for donor versus recipient selection.

Dietary Patterns and Risk of Gleason Grade Progression among Men on Active Surveillance for Prostate Cancer: Results from the Canary Prostate Active Surveillance Study

Modifiable lifestyle factors, such as following a healthy dietary pattern may delay or prevent prostate cancer (PCa) progression. However, few studies have evaluated whether following specific dietary patterns after PCa diagnosis impacts risk of disease progression among men with localized PCa managed by active surveillance (AS). 564 men enrolled in the Canary Prostate Active Surveillance Study, a protocol-driven AS study utilizing a pre-specified prostate-specific antigen monitoring and surveillance biopsy regimen, completed a food frequency questionnaire (FFQ) at enrollment and had ≥ 1 surveillance biopsy during follow-up. FFQs were used to evaluate adherence to the Dietary Guidelines for Americans (Healthy Eating index (HEI))-2015, alternative Mediterranean Diet (aMED), and Dietary Approaches to Stop Hypertension (DASH) dietary patterns. Multivariable-adjusted hazards ratios (HRs) and 95% confidence intervals were estimated using Cox proportional hazards models. During a median follow-up of 7.8 years, 237 men experienced an increase in Gleason score on subsequent biopsy (grade reclassification). Higher HEI-2015, aMED or DASH diet scores after diagnosis were not associated with significant reductions in the risk of grade reclassification during AS. However, these dietary patterns have well-established protective effects on chronic diseases and mortality and remain a prudent choice for men with prostate cancer managed by AS.

Deceased-Donor Acute Kidney Injury and Acute Rejection in Kidney Transplant Recipients: A Multicenter Cohort

Donor acute kidney injury (AKI) activates innate immunity, enhances HLA expression in the kidney allograft, and provokes recipient alloimmune responses. We hypothesized that injury and inflammation that manifested in deceased-donor urine biomarkers would be associated with higher rates of biopsy-proven acute rejection (BPAR) and allograft failure after transplantation. Prospective cohort. 862 deceased donors for 1,137 kidney recipients at 13 centers. We measured concentrations of interleukin 18 (IL-18), kidney injury molecule 1 (KIM-1), and neutrophil gelatinase-associated lipocalin (NGAL) in deceased donor urine. We also used the Acute Kidney Injury Network (AKIN) criteria to assess donor clinical AKI. The primary outcome was a composite of BPAR and graft failure (not from death). A secondary outcome was the composite of BPAR, graft failure, and/or de novo donor-specific antibody (DSA). Outcomes were ascertained in the first posttransplant year. Multivariable Fine-Gray models with death as a competing risk. Mean recipient age was 54 ± 13 (SD) years, and 82% received antithymocyte globulin. We found no significant associations between donor urinary IL-18, KIM-1, and NGAL and the primary outcome (subdistribution hazard ratio [HR] for highest vs lowest tertile of 0.76 [95% CI, 0.45-1.28], 1.20 [95% CI, 0.69-2.07], and 1.14 [95% CI, 0.71-1.84], respectively). In secondary analyses, we detected no significant associations between clinically defined AKI and the primary outcome or between donor biomarkers and the composite outcome of BPAR, graft failure, and/or de novo DSA. BPAR was ascertained through for-cause biopsies, not surveillance biopsies. In a large cohort of kidney recipients who almost all received induction with thymoglobulin, donor injury biomarkers were associated with neither graft failure and rejection nor a secondary outcome that included de novo DSA. These findings provide some reassurance that centers can successfully manage immunological complications using deceased-donor kidneys with AKI.

S764 Yield of Dysplasia Surveillance Biopsies in Inflammatory Bowel Disease

Introduction: Inflammatory bowel disease (IBD) dysplasia surveillance protocols call for a representative number of untargeted or 'random' biopsies to increase the odds of detection of 'invisible' or flat dysplasia. In current practice, the benefit of untargeted surveillance biopsies over a targeted surveillance approach with or without adjunctive chromoendoscopy is unclear. Our study retrospectively examines outcomes of endoscopic dysplasia surveillance at a single institution and compares yields of targeted and untargeted biopsies for the detection of dysplasia from both chromoendoscopy (CE) and traditional high definition white light (HD-WLE) examinations. Methods: A retrospective chart review of all IBD patients (ulcerative colitis, Crohns, and indeterminate colitis) undergoing dysplasia surveillance at a single center between 1/2015 and 10/2021 was performed. Patients younger than 18 and those with a pre-existing diagnosis of dysplasia or cancer were excluded. All surveillance exams done for each patient during the study period were reviewed. Presence or absence of endoscopic and microscopic inflammation, use of targeted biopsies or polypectomy, number of untargeted biopsies, and presence or absence of dysplasia from both targeted and untargeted biopsies were noted for both HD-WLE and CE exams. All instances of ‘invisible’ dysplasia were confirmed by a second reviewer following manual review of endoscopy and pathology reports. Results: 200 IBD patients (96 UC, 94 Crohns, 10 indeterminate) underwent 492 endoscopic surveillance procedures (199 CE, 293 WLE). 11,094 untargeted biopsies and 242 targeted biopsies or polypectomies were performed. Invisible dysplasia was detected 9 times for a yield of 0.06% per untargeted biopsy. 37.2% of endoscopically targeted biopsies or polypectomies were positive for dysplasia (39.6% CE, 33.9% WLE) and accounted for 90.9% of dysplasia detected during the study period. Conclusion: Random biopsies are a low yield means for detection of dysplasia, accounting for < 10% of dysplastic lesions observed during the study period. No patients with ‘invisible’ dysplasia had PSC, opted for colectomy, or had evidence of progression on follow up examination. Given the high yield of targeted biopsy and polypectomy, and low likelihood of missed high risk lesions if untargeted biopsies are not performed, it may be reasonable to emphasize high quality endoscopic examination and targeted biopsies/polypectomies and to de-emphasize the role of untargeted random biopsies.

S3581 Common Variable Immunodeficiency and Gastric Carcinogenesis: Two Illustrative Cases

Introduction: Common variable immunodeficiency (CVID) is linked to an increased risk for gastric cancer which seems to be associated with achlorhydria, H. pylori infection, decreased production of gastric IgA, and autoimmune phenomena. We present two patients illustrating progression of gastric pathology in CVID through dysplasia to cancer. Case Description/Methods: A 42-year-old woman with CVID presented with dyspepsia, diarrhea and a 75 lb weight loss. Small intestinal bacterial overgrowth was diagnosed and treated. EGD revealed a superficial ulcer at the incisura. Pathological examination demonstrated chronic active gastritis with H. pylori and intestinal metaplasia (IM) without dysplasia. Triple therapy was unsuccessful; repeat EGD 1 year later demonstrated 3 superficial ulcers at the incisura and antrum; biopsies revealed chronic active gastritis with H. pylori and IM without dysplasia. Second-line therapy failed. 3 years later, EGD showed a non-bleeding cratered ulcer with a nodular edge on the greater curvature in the antrum. Biopsies demonstrated an invasive tubular adenocarcinoma arising in a background of IM with low and high grade dysplasia and no evidence of H. pylori. Partial gastrectomy with Roux-en-Y gastrojejunostomy and modified D2 lymphadenectomy was performed. Pathologic examination confirmed a T1aN0M0 moderately differentiated adenocarcinoma. A 64-year-old woman with CVID, celiac disease, pernicious anemia and a CTLA4 gene mutation presented in 2019 for surveillance following removal of a gastric adenoma by EMR 2 months earlier. From 2018-2022, EGDs with gastric mapping were performed every 6 months and revealed progression from low to focal high grade dysplasia. In 2019, surveillance biopsies showed foci of low and high grade dysplasia in the antrum. EMR of a sessile polyp and ESD of 2 sessile polyps were performed followed by EMR of a sessile antral polyp and EMR of diffusely nodular mucosa at the incisura 5 months later. Biopsies have been consistently negative for H. pylori. Discussion: These cases illustrate progression to cancer in CVID and exemplify two risk factors: Helicobacter pylori and achlorhydria. Both progressed from low to high grade dysplasia and, in one, to invasive cancer within 4 years. Guidance on surveillance for IM in the non-CVID population varies in terms of frequency and intervals; with the risk of progression to cancer in CVID increased 10-47-fold, there is an urgent need for guidelines on surveillance.

Prospective comparison of restriction spectrum imaging and non-invasive biomarkers to predict upgrading on active surveillance prostate biopsy.

Protocol-based active surveillance (AS) biopsies have led to poor compliance. To move to risk-based protocols, more accurate imaging biomarkers are needed to predict upgrading on AS prostate biopsy. We compared restriction spectrum imaging (RSI-MRI) generated signal maps as a biomarker to other available non-invasive biomarkers to predict upgrading or reclassification on an AS biopsy. We prospectively enrolled men on prostate cancer AS undergoing repeat biopsy from January 2016 to June 2019 to obtain an MRI and biomarkers to predict upgrading. Subjects underwent a prostate multiparametric MRI and a short duration, diffusion-weighted enhanced MRI called RSI to generate a restricted signal map along with evaluation of 30 biomarkers (14 clinico-epidemiologic features, 9 molecular biomarkers, and 7 radiologic-associated features). Our primary outcome was upgrading or reclassification on subsequent AS prostate biopsy. Statistical analysis included operating characteristic improvement using AUROC and AUPRC. The individual biomarker with the highest area under the receiver operator characteristic curve (AUC) was RSI-MRI (AUC = 0.84; 95% CI: 0.71-0.96). The best non-imaging biomarker was prostate volume-corrected Prostate Health Index density (PHI, AUC = 0.68; 95% CI: 0.53-0.82). Non-imaging biomarkers had a negligible effect on predicting upgrading at the next biopsy but did improve predictions of overall time to progression in AS. RSI-MRI, PIRADS, and PHI could improve the predictive ability to detect upgrading in AS. The strongest predictor of clinically significant prostate cancer on AS biopsy was RSI-MRI signal output.

Clinical Significance of Perineural Invasion in Men With Grade Group 1 Prostate Cancer on Active Surveillance.

We aimed to evaluate the clinical significance of perineural invasion in men on active surveillance for Grade Group 1 prostate cancer. We identified 1,969 men with Grade Group 1 prostate cancer and at least 1 follow-up biopsy. A time-dependent Cox model and a logistic regression model were used to assess the association between biopsy-detected perineural invasion and grade reclassification (defined as the detection of Grade Group ≥2 prostate cancer on a surveillance biopsy), and adverse pathology (defined as Grade Group ≥3 ± seminal vesicle invasion ± lymph node involvement) at radical prostatectomy, respectively. The 198 men with perineural invasion detected during active surveillance had lower rates of grade reclassification-free survival than those without perineural invasion (P < .001). On multivariable analysis perineural invasion was significantly associated with grade reclassification (HR 3.25, 95% CI 2.54-4.16, P < .001); an association that persisted in the multiparametric magnetic resonance imaging subset. At radical prostatectomy, men with biopsy-detected perineural invasion had more extraprostatic extension than men without perineural invasion (Relative Risk 1.71, 95% CI 1.15-2.56). However, on multivariable analysis biopsy-detected perineural invasion was not associated with adverse pathology (OR 0.68, 95% CI 0.27-1.68, P = .40) and these patients did not exhibit more biochemical recurrence at 5 years (P > .05). Perineural invasion during active surveillance was associated with grade reclassification. At radical prostatectomy biopsy-detected perineural invasion patients exhibited more extraprostatic extension but biopsy-detected perineural invasion was not independently associated with more adverse pathology. In addition, these patients did not have more biochemical recurrence during follow-up. Perineural invasion should not preclude Grade Group 1 patients from active surveillance but they may warrant more stringent monitoring.

336.3: Clinical Utility of Donor-Derived Cell-Free DNA During the Period of Recovery of Renal Function After Kidney Transplantation

Background: The transplant of kidneys with high KDPI, and the incidence and duration of delayed graft function (DGF) are risk factors associated with incomplete recovery of kidney function (IRF). In both situations, kidney biopsies are essential to exclude the diagnosis of acute rejection (AR). Purpose: This study evaluates the clinical utility of monitoring donor-derived cell-free DNA (dd-cfDNA), a biomarker of kidney injury, in recipients of high Kidney Donor Profile Index (KDPI) transplants during the period of kidney function recovery. Methods: This is a single center, prospective, cohort study in recipients of high KDPI kidneys who developed delayed graft function (DGF), defined as the need for dialysis within the first week after transplantation. All patients received a single 3 mg/kg anti-thymocyte globulin dose, tacrolimus, mycophenolate, and prednisone. Blood samples were obtained at 14 (D14) and 30 (D30) days to measure the percentage (%) of dd-cfDNA. The dd-cfDNA > 1% is associated with increased probability for acute rejection (AR). Results: This preliminary analysis includes data from 69 patients. The median KDPI was 73% [IQR 47-87] and the mean cold ischemia time was 27± 7 hours. The incidence of DGF was 89.8% with a median duration of 6 (IQR 2 – 9) days. At D14 the median GFR was 12 ml/min/1.73 m2 (IQR 6-21) and the median dd-cfDNA levels were 0.43% (IQR 0.02-0.78), with 19 patients (28%) showing dd-cfDNA >1%. Surveillance biopsies during DGF were performed in 42 (61%) patients showing one T-cell mediated rejection IA (dd-cfDNA of 0.41%) and 4 borderline changes (dd-cfDNA 0.82%, 0.85%, 0.98%, 1.90%). Using dd-cfDNA >1% to guide the indication of the surveillance biopsy, we would have avoided 22 (52%) biopsies but missed 1 (2%) patient with AR. At D30, the median GFR was 36 ml/min/1.73 m2 (IQR 28-48) and the median dd-cfDNA levels were 0.40% (IQR 0.01-0.66), with 12 patients (19%) showing dd-cfDNA >1%. Surveillance biopsies performed in 21 (30.43%) patients with incomplete recovery of kidney function showed 4 borderline changes (dd-cfDNA 0.17%, 0.66%, 0.67%, and 2.80%). Using dd-cfDNA >1% to guide the indication of the surveillance biopsy, we would have avoided 12 (57%) biopsies without missing any AR episodes. Overall, 5 (7%) patients showed dd-cfDNA >1% at D14 and D30, but none of them showed biopsy confirmed AR. Conclusions: This preliminary analysis suggests that monitoring dd-cfDNA may assist clinical decision during the period of DGF and in kidney transplant recipients with incomplete recovery of graft function.

216.2: Acute Tubular Injury and Necrosis Do Not Lead to Meaningful Elevations in Donor-Derived Cell-free DNA (dd-cfDNA)

KOAR registry. Introduction: Associations between non-rejection histologic diagnoses and dd-cfDNA have not been extensively characterized. We explored these associations inkidney transplant recipients enrolled in the Kidney allograft Outcomes AlloSure Registry (KOAR, NCT03326076). Methods: For-cause and surveillance biopsies with NR (no rejection or other abnormalities, except IF/TA) or acute tubular injury/necrosis (ATI/ATN), and paireddd-cfDNA within 30 days were included. The incidence of a composite outcome (eGFR decline > 25%, rejection, and de novo donor-specific antibody detection) at 12 months after biopsy was also assessed. Results: 166 biopsies (141 patients) with NR and 70 biopsies (64 patients) with ATI/ATN were included; compared to patients with ATI/ATN, patients with NRhad lower KDPI (49% vs 64%, p <0.05) and shorter cold ischemia time (13 vs 18 hours, p<0.01). ATI/ATN biopsies were more likely to be for-cause (91.4% vs59.6%, p<0.001), earlier post-transplant (83.0 vs 116.5 days, p<0.001), and occur at lower eGFRs (43 vs 32 mL/min, p<0.001) (Table 1). There was no significant difference in median dd-cfDNA between NR (0.23%, IQR: 0.11 - 0.53) and ATI/ATN (0.21%, IQR: 0.13 - 0.55) biopsies (p = 0.993) (Figure 1). When patients were stratified by dd-cfDNA at the time of their first biopsy (< 0.5% vs ≥ 0.5%), there was a non-significant trend towards a higher incidence of the 12-month clinical composite among those with dd-cfDNA ≥ 0.5% (27.5% vs 12.9%, p=0.53), with eGFR decline being most common (78.5% of events). Conclusions: Our findings suggest that acute tubular injury/necrosis is not associated with substantial elevations in dd-cfDNA. The use of dd-cfDNA to identify patients with non-actionable histologic findings (including ATI/ATN) may allow more nuanced clinical decision-making and reduce the number of unnecessary biopsies.

232.1: Donor-derived Cell-Free DNA Testing in Kidney Transplantation: Do One-month Values Have Any Prognostic Significance?

Introduction: Percutaneous renal allograft biopsy is the current standard for detecting acute rejection after kidney transplantation (KT). Noninvasive tests such as plasma-based donor-derived cell-free DNA (dd-cfDNA) assays have been proposed as an alternative to biopsy. We sought to examine the value of dd-cfDNA testing at one month following KT in different donor and recipient categories. Methods: We performed a single center retrospective review of all adult KT patients (pts) who underwent dd-cfDNA testing between January 2018 and August 2021. The diagnosis of acute rejection was based on histopathology obtained from percutaneous, ultrasound-guided needle biopsies. Our center’s standard practice included dd-cfDNA testing and performing surveillance kidney biopsies at 1 month following KT. The dd-cfDNA test was considered elevated if >1.0%. Results: During the study period, 3157 dd-cfDNA tests were performed in 695 de novo pts. Higher mean 1-month dd-cfDNA levels were noted in the following categories: Retransplants (n=30, 1.8±2.1); highly sensitized pts (PRA 98-100%, n=27, 1.6±2.0; for highly sensitized retransplants, n=18, 2.0±2.3; for highly sensitized primary KTs, n=9, 0.7±0.5); and pts who underwent early reoperations (n=16, 0.85±0.9). In all other KT categories, mean 1-month dd-cfDNA levels were lower and similar: DCD donor KTs (n=53, 0.56±0.4), living donor KTs (n=51, 0.47±0.4); acute kidney injury (AKI) donor KTs (n=23, 0.47±0.6); standard criteria donor (SCD) KTs (n=91, 0.47±0.4); expanded criteria donor (ECD) KTs (n=44, 0.46±0.5); dual KTs (n=16, 0.45±0.4); and pts with delayed graft function (DGF, n=50, 0.46±0.4). In 58 primary KT pts with negative 1-month surveillance biopsies, corresponding mean 1-month dd-cfDNA levels were 0.49±0.4. In 10 pts with positive 1-month surveillance biopsies, corresponding mean 1-month dd-cfDNA levels were 1.5±1.8. In 26 pts with a 1-month dd-cfDNA level >1.0, the subsequent incidence of acute rejection was 27%; in 22 pts with a 1-month dd-cfDNA level ≥2.0, the subsequent incidence of acute rejection was 50% (mean follow-up 14 months). Conclusions: We noted a bimodal distribution of 1-month dd-cfDNA levels. Higher mean 1-month dd-cfDNA levels (range 0.72-2.2) were associated with retransplants, high PRA pts, and pts with early reoperations; 22-44% of these pts had 1-month dd-cfDNA levels >1.0. Conversely, primary KT alone pts (DCD, living donor, AKI donor, SCD, ECD, dual KT, those with DGF) had lower 1-month dd-cfDNA levels (range 0.45-0.56) and only 7-14% had 1-month dd-cfDNA levels >1.0. One-month surveillance biopsy results correlated with corresponding dd-cfDNA levels. Elevated 1-month dd-cfDNA levels occurred in pts at a higher risk for acute rejection, suggesting that these pts need to be monitored more closely.

344.2: Delta Changes in Donor-Derived Cell-Free DNA (dd-cfDNA) Complement the Donor Fraction in Kidney Transplant Surveillance

Introduction: Delta changes in dd-cfDNA levels over time may identify patients with evolving alloimmune injury, providing complementary information to thedonor fraction. We explored the dd-cfDNA trajectories preceding biopsy-proven rejection (BPAR) events among kidney transplant recipients enrolled in theKidney allograft Outcomes AlloSure Registry (KOAR, NCT03326076) and undergoing longitudinal surveillance with dd-cfDNA. Methods: In the primary analysis, we compared the change in dd-cfDNA from baseline to the time of BPAR (for-cause or surveillance biopsies). We identifiedpatients with first-time rejection events and at least 3 prior dd-cfDNA results; the index result was obtained ≤30 days before BPAR; we then selected the lowestof two preceding results as the patient-specific baseline and compared this with the index result. We then analyzed patients with rejection (first or subsequent, atleast 90 days apart) and ≥2 dd-cfDNA results, including one within 30 days of the index biopsy. The reference change value (RCV) was calculated using areference population of patients with stable allograft function, at least 3 dd-cfDNA measurements, and no significant clinical events. Results: A total of 28 patients with BPAR met criteria for the primary analysis; among these, median baseline dd-cfDNA was 0.22% (IQR: 0.19 - 0.35) and mediandd-cfDNA at the time of rejection was 1.35% (IQR: 0.75 - 2.75), representing a 491% (IQR: 177 - 1133) increase between these results, obtained 71.5 (IQR: 46 -113) days apart (Table 1A).51 events met criteria for the second analysis where a median increase of 253% (IQR: 72 - 821%) between sequential dd-cfDNAvalues obtained 69 days (IQR: 45 - 108) apart preceded biopsy-proven rejection events (Table 1B). The calculated RCV for the stable reference population withinKOAR was 56.3%. 39 of these 51 events (76%) demonstrated increases greater than this RCV. Conclusions: Longitudinal surveillance with dd-cfDNA allows the integration of delta changes and trajectories over time, allowing earlier identification ofevolving allograft injury. Significant changes from an established baseline and between sequential values ahead of biopsy-proven rejection highlight how longitudinal surveillance may improve diagnostic performance.

216.9: Urinary Extracellular Vesicle DNA Cargo Reflects Kidney Allograft Injury

Introduction: Following allograft injury, donor-derived cell-free DNA (dd-cfDNA) levels increase. Numerous research studies have demonstrated increased dd-cfDNA levels in blood and urine as biomarkers of kidney allograft injury in patients with transplanted kidney. Extracellular vesicles (EVs) are nanosized particles released by almost all cells. Because of the anatomical proximity of kidney EV-producing cells and urine, (dd)DNA containing urinary EVs (uEVs) are potentially relevant biomarkers of allograft injury. The aim of our study was to explore uEVs and their DNA cargo, to reveal their association with allograft injury and finally to compare their biomarker potential with (dd)cfDNA found directly in the urine of patients with transplanted kidney. Method: We collected a second morning urine sample from 40 patients before surveillance or for-cause biopsy. We also collected blood and biopsy samples for donor-recipient genotyping. Considering histological analysis, we divided patients into normal histology, rejection injury (combination of antibody- (ABMR) and T-cell mediated rejection (TCMR)), and non-rejection injury group. First, we isolated uEVs (using protocol based on size-exclusion chromatography), their DNA cargo (uEV-DNA), and cfDNA from urine. We used nanoparticle tracking analysis to determine the concentration and size of uEVs. For DNA parameter analysis, including yield, copy number, integrity index, and donor-derived fraction, we used fluorometry and digital droplet PCR. We applied DNase assay and electron microscopy (TEM) immunogold labelling technique to investigate whether DNA was present inside or outside the uEVs. Results: The median uEV concentration was 8.47x1010/ mmol U-creatinine. The concentration was similar in all patient groups, whereas the size parameter differed significantly, as patients with rejection and non-rejection injury had significantly larger uEVs compared with patients with normal histology (177.5 nm and 174.1 nm vs. 160.7 nm, respectively; P=0.045). DNA co-isolated with uEVs and in several parameters correlated with urinary cfDNA. uEV-DNA and cfDNA yields (Figure 1A) and DNA copy number (Figure 1B) were significantly higher in both allograft injury groups. For uEV-DNA, the copy number of donor-derived DNA was significantly higher in patients with ABMR than in patients with TCMR (3044.3 vs. 680.9 copies, respectively; P=0.036). Regarding the long/short gene amplicon ratio, uEV-DNA (green) was less fragmented compared with cfDNA (yellow; Figure 1C). The TEM DNA labelling showed that the DNA was bound to the EV surface. uEV-DNA characteristics correlated with interstitial inflammation, inflammation in areas of fibrosis, and combination of glomerulitis and peritubular capillaritis Banff scores. Conclusion: In kidney transplant recipients, DNA bound to the surface of uEVs reflects allograft injury, particularly allograft rejection and is therefore a suitable potential biomarker for kidney allograft injury.Slovenian Research Agency Grants P3-0323, P1-0170, P4-0165, P4-0407.

P8.045: Modern Medicine Needs Modern Technology Tools

Introduction: Early detection of subclinical rejection is critical to prevent the allograft loss. Currently used methods to detect subclinical rejection include surveillance biopsy protocol, serum creatinine level, eGFR or DSA; however, these methods have limited sensitivity and specificity to accurately detect subclinical rejection. Donor derived cell-free DNA (dd cf-DNA) is a non-invasive biomarker for allograft injury and has been shown to predict allograft rejection with higher sensitivity to detect subclinical rejection compare to some methods (1,2). Here, we show the value of dd cf-DNA in detecting early allograft rejection by presenting two cases where dd cf-DNA assay, AlloSure (CareDx) detected subclinical rejection while other indicators showed stable allograft function. Methods: Ochsner uses AlloSure (CareDx) for a surveillance for the high-risk patients. Results: Thirty-two years old Caucasian female with end stage kidney disease secondary to HIV infection underwent deceased-donor renal transplant in 2018 with KDPI 19% and cPRA 84%. Serum creatinine level had been stable at 1.1mg/dL to 1.2mg/dL post-transplant. This patient was monitored using AlloSure (CareDx) for 1-,2-,3-,4-,6- and 9-month post-transplant. AlloSure values for month 1 to 6 were <0.21, which indicates stable allograft function. However, at 9-month post-transplant, AlloSure value went up to 4.5%, which indicates possible allograft injury, while serum creatinine level remained stable at 1.2 mg/dL with low level of class 2 DSA (DR-1573). Despite stable creatinine level and low level DSA, we initiated biopsy because of sharp increase in AlloSure value. Biopsy revealed acute T-cell mediated rejection and acute vascular rejection. The second case is a 33 years-old Caucasian female with history of previous renal transplant. The first allograft failed in 2018 due to renal artery and vein thrombosis. The patient underwent deceased donor kidney transplant in 2019. Serum creatinine level was stable at 1.0 – 1.3 mg/dL and sharp increase in respectively. At month 3, AlloSure value went up to 0.78% but DSA was negative. We initiated biopsy based on increase in AlloSure value and it revealed acute antibody mediated rejection (ABMR) (Figure 1). The third case is a 56 years-old male with history of end-stage renal disease secondary to hypertension. The patient received deceased donor kidney transplant in 2017. He developed acute renal failure (Cr went up from 1.2 mg/dl to 1.7 mg/dL) few months after kidney transplant and his kidney biopsy showed acute antibody mediated rejection and T-cell mediated rejection which were treated. At 1-year post-transplant, serum creatinine level remained 1.2 mg/dL to 1.3 mg/dL. He was place on monthly Allosure surveillance. The first value was 1.9%, which indicate possible allograft injury. Monthly monitoring showed increase trend in AlloSure value up to 4.1% while Cr remained stable at 1.2 mg/dL-1.3 mg/dL. At that point, biopsy was performed, and it revealed acute antibody mediated rejection and chronic active antibody rejection. Patient was treated with for ABMR. In addition, monthly Tocilizumab was considered for chronic active antibody mediated rejection for 6 months. AlloSure values reflected the early detection of rejection in a patient with stable Cr as well as the efficacy of treatment with down trending values (Figure 2). Conclusion: For all 3 cases, biopsy would not have been initiated most likely due to stable creatinine level and weak or negative DSA. If this had gone untreated for long period of time, this would have led to significant decrease in graft survival. These cases demonstrate that normal serum creatinine does not mean patient has no active inflammatory process. When other indicators are normal/stable, AlloSure was able to detect early rejection. All three cases demonstrated the value of AlloSure as a monitoring tool for detection of early allograft rejection.

Long-term immunological outcomes of early subclinical inflammation on surveillance kidney allograft biopsies

The long-term impact of early subclinical inflammation (SCI) through surveillance biopsy has not been well studied. To do this, we recruited a prospective observational cohort that included 1000 sequential patients who received a kidney transplant from 2013-2017 at our center. A total of 586 patients who underwent a surveillance biopsy in their first year post-transplant were included after excluding those with clinical rejections, and those who were unable to undergo a surveillance biopsy. Patients were classified based on their biopsy findings: 282 with NSI (No Significant Inflammation) and 304 with SCI-T (SCI and Tubulitis) which was further subdivided into 182 with SC-BLR (Subclinical Borderline Changes) and 122 with SC-TCMR (Subclinical T Cell Mediated Rejection, Banff 2019 classification of 1A or more). We followed the clinical and immunological events including Clinical Biopsy Proven Acute Rejection [C-BPAR], long-term kidney function and death-censored graft loss over a median follow-up of five years. Episodes of C-BPAR were noted at a median of two years post-transplant. Adjusted odds of having a subsequent C-BPAR was significantly higher in the SCI-T group [SC-BLR and SC-TCMR] compared to NSI 3.8 (2.1-7.5). The adjusted hazard for death-censored graft loss was significantly higher with SCI-T compared to NSI [1.99 (1.04-3.84)]. Overall, SCI detected through surveillance biopsy within the first year post-transplant is a harbinger for subsequent immunological events and is associated with a significantly greater hazard for subsequent C-BPAR and death-censored graft loss. Thus, our study highlights the need for identifying patients with SCI through surveillance biopsy and develop strategies to prevent further alloimmune injuries.

Risk of progression following a negative biopsy in prostate cancer active surveillance

BackgroundCurrently, follow-up protocols are applied equally to men on active surveillance (AS) for prostate cancer (PCa) regardless of findings at their initial follow-up biopsy. To determine whether less intensive follow-up is suitable following negative biopsy findings, we assessed the risk of converting to active treatment, any subsequent upgrading, volume progression (>33% positive cores), and serious upgrading (grade group >2) for negative compared with positive findings on initial follow-up biopsy.Methods13,161 men from 24 centres participating in the Global Action Plan Active Surveillance Prostate Cancer [GAP3] consortium database, with baseline grade group ≤2, PSA ≤ 20 ng/mL, cT-stage 1–2, diagnosed after 1995, and ≥1 follow-up biopsy, were included in this study. Risk of converting to treatment was assessed using multivariable mixed-effects survival regression. Odds of volume progression, any upgrading and serious upgrading were assessed using mix-effects binary logistic regression for men with ≥2 surveillance biopsies.Results27% of the cohort (n = 3590) had no evidence of PCa at their initial biopsy. Over 50% of subsequent biopsies in this group were also negative. A negative initial biopsy was associated with lower risk of conversion (adjusted hazard ratio: 0.45; 95% confidence interval [CI]: 0.42–0.49), subsequent upgrading (adjusted odds ratio [OR]: 0.52; 95%CI: 0.45–0.62) and serious upgrading (OR: 0.74; 95%CI: 0.59–92). Radiological progression was not assessed due to limited imaging data.ConclusionDespite heterogeneity in follow-up schedules, findings from this global study indicated reduced risk of converting to treatment, volume progression, any upgrading and serious upgrading among men whose initial biopsy findings were negative compared with positive. Given the low risk of progression and high likelihood of further negative biopsy findings, consideration should be given to decreasing follow-up intensity for this group to reduce unnecessary invasive biopsies.

Follow-up of men with a PI-RADS 4/5 lesion after negative MRI/Ultrasound fusion biopsy

Magnetic resonance imaging/Ultrasound (MRI/US) fusion targeted biopsy (TB) in combination with a systematic biopsy (SB) improves cancer detection but limited data is available how to manage patients with a Prostate Imaging-Reporting and Data System (PI-RADS) ≥ 4 lesion and a negative biopsy. We evaluate the real-world management and the rate of clinically significant Prostate Cancer (csPCa) during follow-up. 1546 patients with a multi-parametric MRI (mpMRI) and a PI-RADS ≥ 3 who underwent SB and TB between January 2012 and May 2017 were retrospectively analyzed. 222 men with a PI-RADS ≥ 4 and a negative biopsy were included until 2019. For 177/222 (80%) complete follow-up data was obtained. 66/84 (78%) had an initial PI-RADS 4 and 18 (22%) a PI-RADS 5 lesion. 48% (84/177) received a repeat mpMRI; in the follow-up mpMRI, 39/84 (46%) lesions were downgraded to PI-RADS 2 and 11 (13%) to PI-RADS 3; three cases were upgraded and 28 lesions remained consistent. 18% (32/177) men underwent repeated TB and csPCa was detected in 44% (14/32). Our study presents real world data on the management of men with a negative TB biopsy. Men with a positive mpMRI and lesions with high suspicion (PI-RADS4/5) and a negative targeted biopsy should be critically reviewed and considered for repeat biopsy or strict surveillance. The optimal clinical risk assessment remains to be further evaluated.

Chronic Active Antibody-mediated Rejection in Kidney Transplant Recipients: Treatment Response Rates and Value of Early Surveillance Biopsies.

Background.There is limited information on the value of short-term invasive and noninvasive monitoring in kidney transplant recipients (KTR) undergoing therapy for chronic active antibody-mediated rejection (cAMR).Methods.We describe response rates in patients with cAMR receiving pulse steroids/IVIG ± rituximab 3-mo after index biopsy.Results.The study included 82 consecutive KTR. Mean time from transplant to cAMR was 10 y. Mean peritubular capillaritis (ptc), glomerulitis (g), microvascular inflammation (MVI), C4d, and cg Banff scores were 1.1, 2.1, 3.2, 0.2, and 2, respectively. Mean estimated glomerular filtration rate (eGFR) and urine protein creatinine (UPC) ratio were 38 mL/min and 1.6 g/g, respectively. Thirty (37%) patients lost their allograft during the mean follow-up of 2.4 y. In patients treated with pulse steroids/IVIG (n = 41), response rates for eGFR, UPC, donor-specific antibodies (DSAs), and MVI were 27%, 49%, 7%, and 19%, respectively. In the pulse steroids/IVIG/rituximab group, response rates were 66%, 61%, 20%, and 69%, respectively. Univariate analysis identified response in eGFR (HR = 0.03; P = 0.001; 95% CI, 0.004-0.26), UPC (HR = 0.38; P = 0.01; 95% CI, 0.18-0.82), and DSA (HR = 0.11; P = 0.004; 95% CI, 0.02-0.49) as predictors of graft survival. Multivariate analysis only retained eGFR response (HR = 0.12; P = 0.01; 95% CI, 0.02-0.64).Conclusions.In cAMR, short-term response to treatment for kidney function and DSA was associated with graft survival, but the role of early surveillance biopsies needs further evaluation.

Intensity of observation with active surveillance or watchful waiting in men with prostate cancer in the United States.

Population-based studies assessing various active surveillance (AS) protocols for prostate cancer, to date, have inferred AS participation by the lack of definitive treatment and use of post-diagnostic testing. This is problematic as evidence suggests that most men do not adhere to AS protocols. We sought to develop a novel method of identifying men on AS or watchful waiting (WW) independent of post-diagnostic testing and aimed to identify possible predictors of follow-up intensity in men on AS/WW. A predictive model was developed using SEER watchful waiting data to identify men ≥66 years on AS between 2010-2015, irrespective of post-diagnostic testing, and applied to SEER-Medicare database. AS intensity among different variables including age, prostate-specific antigen (PSA) level, number of total and positive biopsy cores, Charlson comorbidity index, race (Black vs. non-Black), US census region, and county poverty, income, and education levels were compared using multivariable regression analyses for PSA testing, surveillance biopsy, and magnetic resonance imaging (MRI). A total of 2238 men were identified as being on AS. Of which, 81%, 33%, and 10% had a PSA test, surveillance biopsy, and MRI scan within 1-2 years, respectively. On multivariable analyses, Black men were less likely to have a PSA test (adjusted rate ratio [ARR] 0.60, 95% CI: 0.53-0.69), MRI scan (ARR 0.40, 95% CI: 0.24-0.68), and surveillance biopsy (ARR 0.71, 95% CI: 0.55-0.92) than non-Black men. Men within the highest income quintile were more likely to undergo PSA test (ARR 1.16, 95% CI: 1.05-1.27) and MRI scan (ARR 1.60, 95% CI 1.15-2.27) compared to men with the lowest income. Black men and men with lower incomes on AS underwent less rigorous monitoring. Further study is needed to understand and ameliorate differences in AS rigor stemming from sociodemographic differences.

The Effect of the COVID-19 Pandemic in Intestinal Rehabilitation and Transplant Patients: Initial Results of the Intestinal Rehabilitation and Transplant Association's International Survey.

The Effect of the COVID-19 Pandemic in Intestinal Rehabilitation and Transplant Patients: Initial Results of the Intestinal Rehabilitation and Transplant Association's International Survey.

Abstract 689: A randomized phase III study assessing the efficacy of liquid biopsy in early diagnosis of recurrence and second malignancies in lung cancer survivors

Abstract We designed a 6,000-patient prospective, multi-institutional randomized clinical trial to assess the efficacy of liquid biopsy in early diagnosis of recurrence and second malignancies in lung cancer survivors. To ensure over 25% of participants are of disadvantaged or minority status, we have recruited multiple community hospitals (Jamaica, Flushing, Wyckoff, and Staten Island/Bronx satellites of Northwell hospitals) to the study in partnership with Memorial Sloan Kettering Cancer Center. Patients included in this study are survivors of non-metastatic non-small cell lung cancer, status-post definitive treatment (surgery or radiation) with no evidence of disease for at least one year. These patients may be on maintenance therapy for their prior lung cancer but may not have any other active malignancy at the time of enrollment. Participants will be randomized 1:1 to standard surveillance at the discretion of the treating physician or standard surveillance plus six-monthly methylation-based liquid biopsy tests over a two-year study period, and strict guidelines on follow-up of positive liquid biopsy testing will be provided to reduce harms from false positives or overdiagnosis. The primary endpoint of this study is the incidence of late stage cancer (distant recurrence or new primary cancer of stage III/IV). Secondary endpoints include incidence of early cancers (locoregional recurrence or new primary cancer of stage I/II), metastasis-free survival, and utilization of liquid biopsy versus standard of care scans. We will stratify our results by minority and socioeconomic status to specifically ascertain the effect of this intervention on populations of need. This is the first randomized controlled trial of liquid biopsy in a survivor population and the first trial utilizing liquid biopsy in a large minority population. We will have preliminary experiences to report in April 2022. Citation Format: Sana Raoof. A randomized phase III study assessing the efficacy of liquid biopsy in early diagnosis of recurrence and second malignancies in lung cancer survivors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 689.