Schaeffer, David F.

SummaryBackgroundColitis is a significant complication of immune checkpoint inhibitors (ICI). Currently, clinical and endoscopic severity are used to guide therapy.AimsTo investigate associations between clinical, endoscopic, and histological features with outcomesMethodsWe identified 149 patients from seven institutions with biopsy‐proven ICI colitis. Biopsies were evaluated for histological features including the Geboes score, and the Robarts histopathological index (RHI) was calculated. Clinical, endoscopic, and histological data were tested for associations with biological use and adverse colitis outcomes (biological‐refractory colitis, colectomy or death from colitis).ResultsThree mutually exclusive histological patterns were identified: acute colitis, chronic active colitis and microscopic colitis. Microscopic colitis was associated with older age (68.5 vs 61 years for acute colitis pattern, P = 0.02) and longer time to colitis (5.5 vs 3 months for the other patterns, P = 0.05). Biological use was associated with earlier time to colitis (2 vs 3 months, P = 0.04) and higher RHI (18 vs 12, P = 0.007). On multivariate analysis, RHI ≥14 was associated with biological use with an odds ratio of 4.5 (95% CI 1.4‐13.8; P = 0.01). Adverse colitis outcomes were associated with shorter time to colitis (2 vs 3 months, P = 0.008) and higher RHI (24 vs 14, P = 0.001). On multivariate analysis, RHI ≥24 was associated with adverse colitis outcomes with an odds ratio 9.5 (95% CI 2.1‐42.3 P = 0.003).ConclusionHistological activity as measured by RHI is the only factor independently associated with biological use and adverse colitis outcomes. Prospective studies are needed to validate these findings to determine if histological activity should be incorporated into therapeutic algorithms.

LINKED CONTENTThis article is linked to Pai et al and Buckle & Christensen papers. To view these articles, visit https://doi.org/10.1111/apt.16142 and https://doi.org/10.1111/apt.16203

Abstract Background The operating properties of histologic indices are poorly characterized in Crohn’s disease (CD) and no validated index exists. We assessed the reliability and responsiveness of histologic indices/items, developed an exploratory index, and compared different methods of scoring. Methods Using baseline and week 12 histologic image sets from the EXTEND placebo-controlled trial, blinded central readers scored 4 histologic indices (the Global Histologic Activity Score [GHAS], Geboes Score [GS], Robarts Histopathology Index [RHI], and Nancy Index [NHI]) and 3 additional novel items identified by an expert panel (mucin depletion, basal plasmacytosis, and pyloric gland metaplasia in the ileum). Reliability and responsiveness were evaluated for a global score (4 colonic segments + ileum), colonic score (4 colonic segments) and ileal score (ileum only) using the intraclass correlation coefficient (ICC) and area under the receiver operating curve (AUC), respectively. Change was defined using treatment assignment and improvement in histologic disease activity as measured on a 100-mm visual analogue scale (VAS) in responsiveness testing. Exploratory indices were developed using backward stepwise linear regression analysis. Candidate independent variables were items with an ICC ≥0.4 and AUC ≥0.56. The VAS served as the dependent variable. Results Paired histologic images were analysed from 55 subjects. Inter-rater reliability was substantial to almost perfect (ICC=0.73-0.85) and responsiveness was small to large (treatment assignment AUC=0.50-0.65; VAS AUC=0.71-0.94). The GHAS, GS, RHI, and NHI reached the minimum threshold for reliability (ICC ≥0.4) and responsiveness (AUC ≥0.56) regardless of whether the global and colonic scores were calculated using the worst affected segment, average of the included segments, or sum of the included segments (Table 1-3). Five items were tested as candidate predictors. Three exploratory indices were developed, each consisting of 3 items: a global index (neutrophils in the lamina propria, neutrophils in the epithelium, and erosion/ulceration), colonic index (chronic inflammatory infiltrate, neutrophils in the lamina propria, and erosion/ulceration) and ileal index (chronic inflammatory infiltrate, neutrophils in the epithelium, and erosion/ulceration). The novel indices highly correlated with the GHAS, GS, RHI, and NHI, with correlation coefficients ≥0.80 (Table 4). Conclusion The 4 existing indices were similarly reliable and responsive in measuring CD histologic activity, regardless of the method for calculating global and colonic scores and could be used in clinical trials. Attempts at novel index development did not offer benefit over current histologic indices.

Immune checkpoint inhibitor-associated colitis (ICIC) affects approximately 15% of cancer patients treated with immunotherapy. Although histological evaluation is potentially valuable for both the diagnosis of ICIC and evaluation of disease activity, use in clinical practice is heterogeneous. We aimed to develop expert recommendations to standardize histological assessment of disease activity in patients with ICIC. Using the modified Research and Development/University of California Los Angeles (RAND/UCLA) appropriateness methodology, an international panel of 11 pathologists rated the appropriateness of 99 statements on a 9-point Likert scale during two rounds of anonymous voting. Results were discussed between rounds using moderated videoconferences. There are currently no disease-specific instruments for assessing histological features of ICIC. The panel considered that colonoscopy with at least three biopsies per segment from a total of at least five segments, including both endoscopically normal and inflamed areas, was appropriate for tissue acquisition. They agreed that biopsies should be oriented such that the long axis of the colonic crypts is visualized and should be stained with hematoxylin and eosin. Histological items that the panel voted were appropriate to evaluate in ICIC included the degree of structural/architectural change, chronic inflammatory infiltrate, lamina propria and intraepithelial neutrophils, crypt abscesses and destruction, erosions/ulcerations, apoptosis, surface intraepithelial lymphocytosis, and subepithelial collagen thickness. The appropriateness of routine immunohistochemistry was uncertain. These expert recommendations will help standardize assessment of histological activity in patients with ICIC. The panel also identified the development and validation of an ICIC-specific histological index as a research priority.

INTRODUCTION: The optimal instrument for assessing histologic disease activity in patients with eosinophilic esophagitis (EoE) is unclear. We assessed the responsiveness of the EoE Histologic Scoring System (EoE-HSS) when compared with that of the peak eosinophil count (PEC). METHODS: Histopathology slides were obtained from patients with EoE at baseline and after 8 weeks of treatment with swallowed topical budesonide or elimination diet. Two blinded gastrointestinal pathologists scored biopsies on the EoE-HSS, PEC, and 100-mm visual analog scale (VAS) of overall histologic severity. Change was defined as an improvement by ≥0.5 SD in baseline VAS. Responsiveness was quantified using the standardized effect size (SES) and the probability that the index distinguishes a patient with improvement from a patient without improvement, which is the area under the receiver operating characteristic curve (AUC). Longitudinal validity was assessed using Pearson correlations between changes in EoE-HSS and both PEC and VAS. RESULTS: The EoE-HSS grade (SES 2.18 [95% confidence interval, CI: 1.46–2.88]; AUC 0.73 [95% CI: 0.57–0.84]) and stage (SES 2.07 [95% CI: 1.37–2.77]; AUC 0.73 [95% CI: 0.58–0.84]) were highly responsive, similar to PEC (SES 1.44 [95% CI: 0.80–2.07]; AUC 0.73 [95% CI: 0.58–0.84]). The EoE-HSS grade and stage were more highly correlated with changes in VAS (grade 0.92 [95% CI: 0.86–0.95]; stage 0.89 [95% CI: 0.81–0.94]) than with changes in PEC (grade 0.74 [95% CI: 0.58–0.85]; stage 0.66 [95% CI: 0.47–0.80]). DISCUSSION: The EoE-HSS is highly responsive, performs similarly to PEC, and is better correlated with changes in overall histologic activity in patients with EoE.

AimsTo develop and validate a deep learning algorithm to quantify a broad spectrum of histological features in colorectal carcinoma.Methods and resultsA deep learning algorithm was trained on haematoxylin and eosin‐stained slides from tissue microarrays of colorectal carcinomas (N = 230) to segment colorectal carcinoma digitised images into 13 regions and one object. The segmentation algorithm demonstrated moderate to almost perfect agreement with interpretations by gastrointestinal pathologists, and was applied to an independent test cohort of digitised whole slides of colorectal carcinoma (N = 136). The algorithm correctly classified mucinous and high‐grade tumours, and identified significant differences between mismatch repair‐proficient and mismatch repair‐deficient (MMRD) tumours with regard to mucin, inflammatory stroma, and tumour‐infiltrating lymphocytes (TILs). A cutoff of >44.4 TILs per mm2 carcinoma gave a sensitivity of 88% and a specificity of 73% in classifying MMRD carcinomas. Algorithm measures of tumour budding (TB) and poorly differentiated clusters (PDCs) outperformed TB grade derived from routine sign‐out, and compared favourably with manual counts of TB/PDCs with regard to lymphatic, venous and perineural invasion. Comparable associations were seen between algorithm measures of TB/PDCs and manual counts of TB/PDCs for lymph node metastasis (all P < 0.001); however, stronger correlations were seen between the proportion of positive lymph nodes and algorithm measures of TB/PDCs. Stronger associations were also seen between distant metastasis and algorithm measures of TB/PDCs (P = 0.004) than between distant metastasis and TB (P = 0.04) and TB/PDC counts (P = 0.06).ConclusionsOur results highlight the potential of deep learning to identify and quantify a broad spectrum of histological features in colorectal carcinoma.

3579 Background: BRAFV600E ( BRAF) mutations (mts) portend poor prognosis in mCRC and patients (pts) may die before ascertainment. Since 2014, Vancouver Coastal Health (VCH) has performed reflex hereditary screening of CRCs with BRAF and mismatch repair (MMR) immunohistochemistry (IHC). We evaluated this BRAF mt population-based cohort ( BRAFPOP) to establish the true prognosis of BRAF mts in mCRC. Methods: We reviewed all mCRCs from VCH between 4/2014 and 5/2018 for BRAF by IHC (VE1 antibody). Overall survival (OS) from stage IV diagnosis was compared to mCRCs with next generation sequencing (NGS) determined BRAF mts ( BRAFNGS) from BC Cancer & MD Anderson. BRAFNGS OS did not differ by center (p = 0.77). Results: See table for BRAF cohort baseline characteristic comparison. BRAFPOP pts had worse OS than BRAFNGS pts (HR 2.5, 95% CI 1.6 – 3.9, P < 0.0001). Median OS for all BRAF mt pts was 17.9 mos. Both groups had worse OS than wild type pts (P < 0.0001). 52 (81%) of BRAFPOP pts were referred to oncology, 40 (63%) received chemotherapy, and 12 (19%) had NGS BRAF testing. BRAFPOP pts who had NGS testing with BRAF mts had OS comparable to other BRAFNGS pts (P = 0.89) and better OS than BRAFPOP pts that never had NGS testing (HR 0.37, 95% CI 0.18-0.76, P = 0.030). Pts with BRAF mts and MMR deficiency (dMMR) (n = 40) had worse OS than MMR proficiency (pMMR, n = 202) (1.6, 95% CI 1.0-2.5, P = 0.011). This was driven by BRAFPOP dMMR pts (HR 1.9, 95% CI 0.9-4.0, P = 0.036) as no difference was seen by MMR in BRAFNGS pts (HR 1.3, 95% CI 0.8-2.2, P = 0.30). Conclusions: Current estimates of prognosis for mCRC with BRAF mts likely underestimate its impact due to referral bias for NGS testing. BRAF mts with dMMR are associated with worse prognosis than pMMR. This appears driven by BRAFPOP pts. [Table: see text]

BACKGROUNDThe cytologic features of undifferentiated pancreatic carcinoma with osteoclastic giant cells (UOC) are rarely described.METHODSCytologic and clinicopathologic characteristics in 15 UOC fine‐needle aspiration (FNA) specimens were analyzed.RESULTSFNA specimens were obtained from 6 men and 8 women with a mean age of 65 years who had UOCs (head, n = 7; body, n = 3; and tail, n = 4) with a mean radiologic size 7.3 cm, and some had a cystic component (n = 9). Three cell types (osteoclastic giant cells, pleomorphic tumor giant cells, and spindled/histiocytoid cells) were observed in 12 of 15 specimens (80%); and pancreatic ductal adenocarcinoma (PDAC) was present in 11 specimens. FNA diagnoses were UOC (n = 6), PDAC (n = 5), poorly differentiated carcinoma (n = 2), “suspicious for neoplasm” (n = 1), and “negative” (n = 1). Five of 5 specimens with osteoclastic giant cells were positive for cluster of differentiation 68 (CD68) (a glycoprotein that binds to low‐density lipoprotein). Pleomorphic tumor giant cells and spindled/histiocytoid cells were positive for pancytokeratin (6 of 7 specimens), CAM5.2 (2 of 3 specimens), and epithelial membrane antigen (2 of 2 specimens). INI‐1 protein expression was retained in 3 of 3 specimens. The Ki‐67 labeling index was assessed in 3 specimens and was 12%, 18%, and 40%; 4 of 12 resected UOCs were pure, and 8 were mixed with PDAC. One resection specimen had intraductal papillary mucinous neoplasm, and 2 had mucinous cystic neoplasms. The median overall survival (OS) of patients who had UOCs identified on FNA was 8 months (6 died [OS, 8 months; range, 2‐22 months], and 8 remained alive [OS, 3 months; range, 1‐27 months]), which was similar to the survival of 74 patients who had PDACs identified on FNA (OS, 15 months; P = .279) but worse than that of the 27 patients with UOCs who did not undergo FNA (OS, 92 months; P = .0135).CONCLUSIONSThe 3 classical UOC cell types are identifiable on FNA, making cytologic diagnosis possible if considered in the differential. A PDAC component is often also observed. The survival advantage of UOC over pure PDAC appears to be negated by FNA and requires further investigation. Cancer Cytopathol 2017;125:563–75. © 2017 American Cancer Society.