Extended Wireless pH Monitoring Significantly Increases Gastroesophageal Reflux Disease Diagnoses in Patients With a Normal pH Impedance Study.

Background/Aims: Extended wireless pH monitoring (WPM) is used to investigate gastroesophageal reflux disease (GERD) as subsequent or alternative investigation to 24-hour catheter-based studies. However, false negative catheter studies may occur in patients with intermittent reflux or due to catheter-induced discomfort or altered behavior. We aim to investigate the diagnostic yield of WPM after a negative 24-hour multichannel intraluminal impedance pH (MII-pH) monitoring study and to determine predictors of GERD on WPM given a negative MII-pH. Methods: Consecutive adult patients (> 18 years) who underwent WPM for further investigation of suspected GERD following a negative 24-hour MII-pH and upper endoscopy between January 2010 and December 2019 were retrospectively included. Clinical data, endoscopy, MII-pH, and WPM results were retrieved. Fisher's exact test, Wilcoxon rank sum test, or Student's t test were used to compare data. Logistic regression analysis was used to investigate predictors of positive WMP. Results: One hundred and eighty-one consecutive patients underwent WPM following a negative MII-pH study. On average and worst day analysis, 33.7% (61/181) and 34.2% (62/181) of the patients negative for GERD on MII-pH were given a diagnosis of GERD following WPM, respectively. On a stepwise multiple logistic regression analysis, the basal respiratory minimum pressure of the lower esophageal sphincter was a significant predictor of GERD with OR = 0.95 (0.90-1.00, P = 0.041). Conclusions: WPM increases GERD diagnostic yield in patients with a negative MII-pH selected for further testing based on clinical suspicion. Further studies are needed to assess the role of WPM as a first line investigation in patients with GERD symptoms.

Low-cost and clinically applicable copy number profiling using repeat DNA.

BACKGROUND: Somatic copy number alterations (SCNAs) are an important class of genomic alteration in cancer. They are frequently observed in cancer samples, with studies showing that, on average, SCNAs affect 34% of a cancer cell's genome. Furthermore, SCNAs have been shown to be major drivers of tumour development and have been associated with response to therapy and prognosis. Large-scale cancer genome studies suggest that tumours are driven by somatic copy number alterations (SCNAs) or single-nucleotide variants (SNVs). Despite the frequency of SCNAs and their clinical relevance, the use of genomics assays in the clinic is biased towards targeted gene panels, which identify SNVs but provide limited scope to detect SCNAs throughout the genome. There is a need for a comparably low-cost and simple method for high-resolution SCNA profiling. RESULTS: We present conliga, a fully probabilistic method that infers SCNA profiles from a low-cost, simple, and clinically-relevant assay (FAST-SeqS). When applied to 11 high-purity oesophageal adenocarcinoma samples, we obtain good agreement (Spearman's rank correlation coefficient, rs=0.94) between conliga's inferred SCNA profiles using FAST-SeqS data (approximately £14 per sample) and those inferred by ASCAT using high-coverage WGS (gold-standard). We find that conliga outperforms CNVkit (rs=0.89), also applied to FAST-SeqS data, and is comparable to QDNAseq (rs=0.96) applied to low-coverage WGS, which is approximately four-fold more expensive, more laborious and less clinically-relevant. By performing an in silico dilution series experiment, we find that conliga is particularly suited to detecting SCNAs in low tumour purity samples. At two million reads per sample, conliga is able to detect SCNAs in all nine samples at 3% tumour purity and as low as 0.5% purity in one sample. Crucially, we show that conliga's hidden state information can be used to decide when a sample is abnormal or normal, whereas CNVkit and QDNAseq cannot provide this critical information. CONCLUSIONS: We show that conliga provides high-resolution SCNA profiles using a convenient, low-cost assay. We believe conliga makes FAST-SeqS a more clinically valuable assay as well as a useful research tool, enabling inexpensive and fast copy number profiling of pre-malignant and cancer samples.

Transition from esophagectomy to endoscopic therapy for early esophageal cancer.

BACKGROUND: To assess the outcomes of patients with early esophageal cancer and high-grade dysplasia comparing esophagectomy, the historical treatment of choice, to endoscopic eradication therapy (EET). METHODS: Retrospective cohort study of consecutive patients with early esophageal cancer/high-grade dysplasia, treated between 2000 and 2018 at a tertiary center. Primary outcomes were all-cause and disease-specific mortality assessed by multivariable Cox regression and a propensity score matching sub analysis, providing hazard ratios (HR) with 95% confidence intervals (CI) adjusted for age, tumor grade (G1/2 vs. G3), tumor stage, and lymphovascular invasion. Secondary outcomes included complications, hospital stay, and overall costs. RESULTS: Among 269 patients, 133 underwent esophagectomy and 136 received EET. Adjusted survival analysis showed no difference between groups regarding all-cause mortality (HR 1.85, 95% CI 0.73, 4.72) and disease-specific mortality (HR 1.10, 95% CI 0.26, 4.65). In-hospital and 30-day mortality was 0% in both groups. The surgical group had a significantly higher rate of complications (Clavien-Dindo ≥3 26.3% vs. endoscopic therapy 0.74%), longer in-patient stay (median 14 vs. 0 days endoscopic therapy) and higher hospital costs(£16 360 vs. £8786 per patient). CONCLUSION: This series of patients treated during a transition period from surgery to EET, demonstrates a primary endoscopic approach does not compromise oncological outcomes with the benefit of fewer complications, shorter hospital stays, and lower costs compared to surgery. It should be available as the gold standard treatment for patients with early esophageal cancer. Those with adverse prognostic features may still benefit from esophagectomy.

Squamous cell carcinoma after radiofrequency ablation for Barrett's dysplasia.

Barrett's oesophagus (BO) is a usually indolent condition that occasionally requires endoscopic therapy. Radiofrequency ablation (RFA) is an effective endoscopic treatment for high grade dysplasia (HGD) and intramucosal cancer in BO. It has a good efficacy, durability and safety profile although complications can occur. Here we describe a case of RFA in a patient with high grade dysplasia. Although the response to treatment was initially very good with the development of neosquamous epithelium, the patient very rapidly developed a squamous cell cancer of the oesophagus confirmed on radiology, histology and immunohistochemistry. Sanger sequencing confirmed that the original HGD and the squamous cell cancer (SCC) were derived from separate clonal origins. The report highlights the fact that SCC of the oesophagus has been noted after endoscopic ablation for BO previously and suggest that ablation of BO may encourage the clonal expansion of cells carrying carcinogenic mutations once a dominant clonal population has been eradicated.

The stem cell organisation, and the proliferative and gene expression profile of Barrett's epithelium, replicates pyloric-type gastric glands.

OBJECTIVE: Barrett's oesophagus shows appearances described as 'intestinal metaplasia', in structures called 'crypts' but do not typically display crypt architecture. Here, we investigate their relationship to gastric glands. METHODS: Cell proliferation and migration within Barrett's glands was assessed by Ki67 and iododeoxyuridine (IdU) labelling. Expression of mucin core proteins (MUC), trefoil family factor (TFF) peptides and LGR5 mRNA was determined by immunohistochemistry or by in situ hybridisation, and clonality was elucidated using mitochondrial DNA (mtDNA) mutations combined with mucin histochemistry. RESULTS: Proliferation predominantly occurs in the middle of Barrett's glands, diminishing towards the surface and the base: IdU dynamics demonstrate bidirectional migration, similar to gastric glands. Distribution of MUC5AC, TFF1, MUC6 and TFF2 in Barrett's mirrors pyloric glands and is preserved in Barrett's dysplasia. MUC2-positive goblet cells are localised above the neck in Barrett's glands, and TFF3 is concentrated in the same region. LGR5 mRNA is detected in the middle of Barrett's glands suggesting a stem cell niche in this locale, similar to that in the gastric pylorus, and distinct from gastric intestinal metaplasia. Gastric and intestinal cell lineages within Barrett's glands are clonal, indicating derivation from a single stem cell. CONCLUSIONS: Barrett's shows the proliferative and stem cell architecture, and pattern of gene expression of pyloric gastric glands, maintained by stem cells showing gastric and intestinal differentiation: neutral drift may suggest that intestinal differentiation advances with time, a concept critical for the understanding of the origin and development of Barrett's oesophagus.

Clonal selection and persistence in dysplastic Barrett's esophagus and intramucosal cancers after failed radiofrequency ablation.

OBJECTIVES: Radiofrequency ablation (RFA) is used to successfully eliminate Barrett's esophagus (BE)-related dysplasia or intramucosal carcinoma and aims to cause reversion to squamous epithelium. However, in 20% of cases RFA fails to return the epithelium to squamous phenotype. Follow-up studies show a similar dysplasia recurrence rate. We hypothesize that failed RFA is due to clonally mutated epithelial populations harbored in RFA-privileged sites and that RFA can select for the mutant clonal expansion. METHODS: A longitudinal case series of 19 patients with BE and high-grade dysplasia or intramucosal carcinoma were studied. DNA was extracted from individual Barrett's glands, deep esophageal glands within mucosal resections and biopsy specimens before and after RFA. Mutations were identified by targeted sequencing of genes commonly mutated in Barrett's adenocarcinoma. RESULTS: Five patients demonstrated persistent post-RFA pathology with persistent mutations, sometimes detected in deep esophageal glands or neighboring squamous epithelium after several rounds of RFA preceded by mucosal resection. Recurrence of pathology in three other patients was characterized by de novo mutations. CONCLUSIONS: Protumorigenic mutations can be found in post-ablation squamous mucosa as well as in mutant deep esophageal glands; both are associated with dysplasia recurrence. Following RFA, non-dysplastic Barrett's epithelium can contain mutant clones that are found in a subsequent adenocarcinoma. Ablation may also drive the clonal expansion of pre-existing clones after a "bottleneck" created by the RFA. Overall, recurrence of dysplasia post RFA reflects the multicentric origins of Barrett's clones and highlights the role of clonal selection in carcinogenesis.

Field cancerization in Barrett's esophagus.

Barrett's esophagus is a columnar metaplasia conferring an increased risk of adenocarcinoma development. Evidence suggests that this increased risk is due to field cancerization - the formation of histologically undistinguishable field of clonally derived, mutant cells within the Barrett's segment. Field cancerization can occur prior to both dysplasia and invasive neoplasia and potentially provides a mechanism for the development of multifocal and metachronous tumors. In the gastrointestinal tract, mutant clones spread predominately by crypt fission; the same is likely to be true in Barrett's lesions. Epithelial interactions in the form of cooperation or competition between epithelial clones, as well as with stromal cells, may further drive clone growth. Field cancerization is a clinically relevant phenomenon, knowledge of which could influence the size of resection margins to enhance prognosis after curative surgery, as well as provide a rationale for the development of effective biomarkers for neoplasia risk in Barrett's esophagus. This may provide a foundation for streamlined surveillance programs to prevent the development of invasive tumors.

Stem cells and their implications for colorectal cancer.

The colonic crypt is home to several multipotent stem cells. These stem cells reside in a niche at the base of the crypt, which controls their behavior and maintains the stem cell's homeostasis through a variety of signaling pathways and interactions. Several attempts have been made to define markers that can identify colonic stem cells, the most useful of which is Lgr5, a Wnt target gene. Although the crypt base contains several stem cells, each colonic crypt comprises a single clone of cells. Investigators have attempted to reconcile these apparently contradictory observations by conducting research into stem cell division. The propagation of stem-cell-acquired mutations through a crypt results in a monocryptal adenoma that, through crypt fission, develops into a microadenoma. Some early adenomas become polyclonal through an as yet unknown mechanism. The discovery of subpopulations of cancer cells that can initiate tumors when implanted into mice has renewed interest in the existence of cancer stem cells, especially with regard to their implications for the use of chemotherapy. Various potential markers of cancer stem cells have been investigated, particularly CD133, but the cancer stem cell theory still has some limitations.