Interobserver variation in CD30 immunohistochemistry interpretation; consequences for patient selection for targeted treatment

AimsCD30 immunohistochemistry (IHC) in malignant lymphoma is used for selection of patients in clinical trials using brentuximab vedotin, an antibody drug-conjugate targeting the CD30 molecule. For reliable implementation in daily practice and meaningful selection of patients for clinical trials, information on technical variation and interobserver reproducibility of CD30 immunohistochemistry (IHC) staining is required. Methods and resultsWe conducted a three-round reproducibility assessment of CD30 scoring for categorised frequency and intensity, including a technical validation, a live polling' pre- and post-instruction scoring round and a web-based round including individual scoring with additional IHC information to mimic daily diagnostic practice. Agreement in all three scoring rounds was poor to fair ( = 0.12-0.35 for CD30-positive tumour cell percentage and = 0.16-0.41 for staining intensity), even when allowing for one category of freedom in percentage of tumour cell positivity ( = 0.30-0.61). The first round with CD30 staining performed in five independent laboratories showed objective differences in staining intensity. In the second round, approximately half the pathologists changed their opinion on CD30 frequency after a discussion on potential pitfalls, highlighting hesitancy in decision-making. Using fictional cut-off points for percentage of tumour cell positivity, agreement was still suboptimal ( = 0.35-0.60). ConclusionsLack of agreement in cases with heterogeneous expression is shown to influence patient eligibility for treatment with brentuximab vedotin, both in clinical practice and within the context of clinical trials, and limits the potential predictive value of the relative frequency of CD30-positive neoplastic cells for clinical response

Dilemmas for the pathologist in the oncologic assessment of pancreatoduodenectomy specimens

A pancreatoduodenectomy specimen is complex, and there is much debate on how it is best approached by the pathologist. In this review, we provide an overview of topics relevant for current clinical practice in terms of gross dissection, and macro- and microscopic assessment of the pancreatoduodenectomy specimen with a suspicion of suspected pancreatic cancer. Tumor origin, tumor size, degree of differentiation, lymph node status, and resection margin status are universally accepted as prognostic for survival. However, different guidelines diverge on important issues, such as the diagnostic criteria for evaluating the completeness of resection. The macroscopic assessment of the site of origin in periampullary tumors and cystic lesions is influenced by the grossing method. Bi-sectioning of the head of the pancreas may offer an advantage in this respect, as this method allows for optimal visualization of the periampullary area. However, a head-to-head comparison of the assessment of clinically relevant parameters, using axial slicing versus bi-sectioning, is not available yet and the gold standard to compare both techniques prospectively might be subject of debate. Further studies are required to validate the various dissection protocols used for pancreatoduodenectomy specimens and their specific value in the assessment of pathological parameters relevant for prognosis

Axial slicing versus bivalving in the pathological examination of pancreatoduodenectomy specimens (APOLLO): a multicentre randomized controlled trial

Background: In pancreatoduodenectomy specimens, dissection method may affect the assessment of primary tumour origin (i.e. pancreatic, distal bile duct or ampullary adenocarcinoma), which is primarily determined macroscopically. This is the first study to prospectively compare the two commonly used techniques, i.e. axial slicing and bivalving. Methods: In four centres, a randomized controlled trial was performed in specimens of patients with a suspected (pre)malignant tumour in the pancreatic head. Primary outcome measure was the level of certainty (scale 0–100) regarding tumour origin by four independent gastrointestinal pathologists based on macroscopic assessment. Secondary outcomes were inter-observer agreement and R1 rate. Results: In total, 128 pancreatoduodenectomy specimens were randomized. The level of certainty in determining the primary tumour origin did not differ between axial slicing and bivalving (mean score 72 [sd 13] vs. 68 [sd 16], p = 0.21), nor did inter-observer agreement, both being moderate (kappa 0.45 vs. 0.47). In pancreatic cancer specimens, R1 rate (60% vs. 55%, p = 0.71) and the number of harvested lymph nodes (median 16 vs. 17, p = 0.58) were similar. Conclusion: This study demonstrated no differences in determining the tumour origin between axial slicing and bivalving. Both techniques performed similarly regarding inter-observer agreement, R1 rate, and lymph node harvest

Classification of colorectal cancer in molecular subtypes by immunohistochemistry

Colorectal cancer (CRC) is a heterogeneous disease, which can be categorized into distinct consensus molecular subtypes (CMSs). These subtypes differ in both clinical as well as biological properties. The gold-standard classification strategy relies on genome-wide expression data, which hampers widespread implementation. Here we describe an immunohistochemical (IHC) Mini Classifier, a practical tool that, in combination with microsatellite instability testing, delivers objective and accurate scoring to classify CRC patients into the main molecular disease subtypes. It is a robust immunohistochemical-based assay containing four specific stainings (FRMD6, ZEB1, HTR2B, and CDX2) in combination with cytokeratin. We also describe an online tool for classification of individual samples based on scoring parameters of these stainings

Volume of surgery for benign colorectal polyps in the last 11 years

Background and Aims: Traditionally large, complex colorectal polyps were managed by surgical resection (SR), and in recent years endoscopic resection (ER) has progressed significantly. However, to what extent ER has replaced SR remains largely unknown. We performed a multicenter retrospective cohort study to assess the volume and volume changes of SR for benign colorectal polyps over the past decade. Methods: Patients who underwent SR for a benign colorectal polyp in the Netherlands between 2005 and 2015 were selected from the prospective nationwide Dutch Pathology Registry (PALGA database). Clinical characteristics were obtained from the charts of patients who underwent SR in the province of Noord-Holland. Results: A total of 5937 patients were treated with SR for a colorectal polyp and the absolute (454-739 per year) and relative volumes (0.20%-0.37% per colonoscopy per year) of SR remained stable. In the province of Noord-Holland, 928 patients (15.6%) underwent SR. In these patients, submucosal lifting and ER were attempted in 19.9% (n = 175) and 15.0% (n = 134). After 2010, patients were more likely to undergo lifting (27.7% vs 11.4%, P <.001) and ER attempts (18.8% vs 10.9%, P = .001) before definitive SR. Twenty-two patients (2.4%) had been referred to another endoscopy clinic. Conclusions: SR for large, complex colorectal polyps is still frequently performed and has remained stable. A small percentage of patients underwent ER attempts before SR, and referral for an additional ER attempt only occurred in a minority of cases. To increase ER attempts, implementation of a regional multidisciplinary referral network should be considere

Optical diagnosis expanded to small polyps: Post-hoc analysis of diagnostic performance in a prospective multicenter study

Background: Optical diagnosis can replace histopathology of diminutive (1-5mm) polyps if surveillance intervals based on optical diagnosis of polyps have≥90% agreement with intervals based on polyp histology and if the negative predictive value (NPV) for predicting neoplastic histology in the rectosigmoid is≥90%. This study aims to assess whether small (6-9mm) polyps can be included in optical diagnosis strategies. Method: This is a post-hoc analysis of a prospective multicenter study in which 27 endoscopists, all performing endoscopies for the Dutch screening program, were trained in optical diagnosis. For 1 year, endoscopists recorded the predicted histology for all lesions detected using narrow-band imaging during 3144 consecutive colonoscopies after a positive fecal immunochemical test, along with confidence levels. Surveillance interval agreement and NPV were calculated for high confidence predictions for polyps of 1-9mm and compared with histopathology. Surveillance interval agreement was calculated using the European Society of Gastrointestinal Endoscopy surveillance guideline. Results: Surveillance interval agreement was 95.4% (confidence interval [CI] 94.2%-96.4%), and NPV for predicting neoplastic histology in the rectosigmoid 90.0% (CI 87.3%-92.2%). The reduction in histology (45.9% vs. 30.5%) and the proportion of patients who could have received direct surveillance advice (15.6% vs. 7.3%) was higher when small polyps were included (P <0.001). T1 cancer was found in seven small polyps (0.33%), five of which would have been discarded without histopathology. Conclusion: Including small polyps in the optical diagnosis strategy improves its efficacy while maintaining performance thresholds. However, there is a small risk of missing T1 cancers when small polyps are included in the optical diagnosis strategy

Optical Diagnosis of Sessile Serrated Polyps: Bottleneck for the Optical Diagnosis Paradigm?

Optical diagnosis of diminutive (1 to 5 mm) polyps could result in a more cost-effective colonoscopy practice. Previous optical diagnosis studies did not incorporate the differentiation of sessile serrated polyps (SSPs). This study aimed to evaluate the impact of optical diagnosis of diminutive SSPs on the overall performance of endoscopic polyp differentiation in daily colonoscopy practice. Endoscopy data were prospectively collected between 2011 and 2014 in a colonoscopy center. Each endoscopist reported a real-time optical diagnosis (SSP, adenoma or hyperplastic polyp) for all lesions in a structured colonoscopy reporting system, using narrow band imaging at their discretion. Study outcomes were accuracy of optical diagnosis, surveillance interval agreement and negative predictive value for diminutive rectosigmoid neoplastic histology based on the optical diagnosis of diminutive polyps compared to histopathology. Of 2853 removed diminutive polyps, 202 (7.1%) were histologically proven SSPs. Optical diagnosis of diminutive SSPs was accurate in 24.4%. Diminutive SSPs determined 6.9% of postpolypectomy surveillance assignments. Inaccurate optical diagnosis of diminutive SSPs led to lower surveillance interval agreement (78.1% vs. 53.3%, P <0.01) and pooled negative predictive value per polyp (84.3% vs. 50.0%; P <0.01) in patients with diminutive SSPs when compared to patients without diminutive SSPs. Accurate endoscopic identification of diminutive SSPs improved from 0% in 2011 to 47% in 2014 (P=0.02). Endoscopic characterization of diminutive SSPs is difficult, impairing overall performance of optical diagnosis in patients with diminutive SSPs. Future optical diagnosis studies should use validated trainings and classification algorithms that include differentiation of SSP

The Impact of Rectal Stump Inflammation after Subtotal Colectomy on Pouch Outcomes in Ulcerative Colitis Patients

Background and Aims: Proctitis after subtotal colectomy with ileostomy for ulcerative colitis [UC] is common, but its impact on short- and long-term outcome after pouch surgery is unknown. The aim of this study was to determine the incidence of proctitis after subtotal colectomy and its impact on postoperative morbidity and pouchitis. Methods: The distal margin of the rectal stump of all consecutive patients undergoing completion proctectomy and pouch procedure for UC, between 1999 and 2017, was revised and scored for active inflammation according to the validated Geboes score, and for diversion proctitis. Pathological findings were correlated to complications after pouch surgery and pouchitis [including therapy-refractory] using multivariate analyses. Results: Out of 204 included patients, 167 [82%] had active inflammation in the rectal stump and diversion colitis was found in 170 specimens [83%]. Overall postoperative complications and anastomotic leakage rates were not significantly different between patients with and without active inflammation in the rectal stump [34.7% vs 32.4%, p = 0.79, and 10.2% vs 5.4%, p = 0.54, respectively]. Active inflammation of the rectal stump was significantly associated with the development of pouchitis [54.3% vs 25.5%, plog = 0.02], as well as with therapy refractory pouchitis [14% vs 0%, plog = 0.05]. Following multivariate analysis, active inflammation was an independent predictor for the development of pouchitis. Diversion proctitis showed no association with these outcome parameters. Conclusions: Active inflammation in the rectal stump after subtotal colectomy occurs in 80% of UC patients and is a predictor for the development of pouchitis and therapy-refractory pouchitis