Andrew P. Barbour

Survival after neoadjuvant chemotherapy or chemoradiotherapy for resectable oesophageal carcinoma: an updated meta-analysis.

BACKGROUND In a previous meta-analysis, we identified a survival benefit from neoadjuvant chemotherapy or chemoradiotherapy before surgery in patients with resectable oesophageal carcinoma. We updated this meta-analysis with results from new or updated randomised trials presented in the past 3 years. We also compared the benefits of preoperative neoadjuvant chemotherapy compared with neoadjuvant chemoradiotherapy. METHODS To identify additional studies and published abstracts from major scientific meetings, we searched Medline, Embase, and Central (Cochrane clinical trials database) for studies published since January, 2006, and also manually searched for abstracts from major conferences from the same period. Only randomised studies analysed by intention to treat were included, and searches were restricted to those databases citing articles in English. We used published hazard ratios (HRs) if available or estimates from other survival data. We also investigated treatment effects by tumour histology and relations between risk (survival after surgery alone) and effect size. FINDINGS We included all 17 trials from the previous meta-analysis and seven further studies. 12 were randomised comparisons of neoadjuvant chemoradiotherapy versus surgery alone (n=1854), nine were randomised comparisons of neoadjuvant chemotherapy versus surgery alone (n=1981), and two compared neoadjuvant chemoradiotherapy with neoadjuvant chemotherapy (n=194) in patients with resectable oesophageal carcinoma; one factorial trial included two comparisons and was included in analyses of both neoadjuvant chemoradiotherapy (n=78) and neoadjuvant chemotherapy (n=81). The updated analysis contained 4188 patients whereas the previous publication included 2933 patients. This updated meta-analysis contains about 3500 events compared with about 2230 in the previous meta-analysis (estimated 57% increase). The HR for all-cause mortality for neoadjuvant chemoradiotherapy was 0.78 (95% CI 0.70-0.88; p<0.0001); the HR for squamous-cell carcinoma only was 0.80 (0.68-0.93; p=0.004) and for adenocarcinoma only was 0.75 (0.59-0.95; p=0.02). The HR for all-cause mortality for neoadjuvant chemotherapy was 0.87 (0.79-0.96; p=0.005); the HR for squamous-cell carcinoma only was 0.92 (0.81-1.04; p=0.18) and for adenocarcinoma only was 0.83 (0.71-0.95; p=0.01). The HR for the overall indirect comparison of all-cause mortality for neoadjuvant chemoradiotherapy versus neoadjuvant chemotherapy was 0.88 (0.76-1.01; p=0.07). INTERPRETATION This updated meta-analysis provides strong evidence for a survival benefit of neoadjuvant chemoradiotherapy or chemotherapy over surgery alone in patients with oesophageal carcinoma. A clear advantage of neoadjuvant chemoradiotherapy over neoadjuvant chemotherapy has not been established. These results should help inform decisions about patient management and design of future trials. FUNDING Cancer Australia and the NSW Cancer Institute.

Whole genomes redefine the mutational landscape of pancreatic cancer

Pancreatic cancer remains one of the most lethal of malignancies and a major health burden. We performed whole-genome sequencing and copy number variation (CNV) analysis of 100 pancreatic ductal adenocarcinomas (PDACs). Chromosomal rearrangements leading to gene disruption were prevalent, affecting genes known to be important in pancreatic cancer (TP53, SMAD4, CDKN2A, ARID1A and ROBO2) and new candidate drivers of pancreatic carcinogenesis (KDM6A and PREX2). Patterns of structural variation (variation in chromosomal structure) classified PDACs into 4 subtypes with potential clinical utility: the subtypes were termed stable, locally rearranged, scattered and unstable. A significant proportion harboured focal amplifications, many of which contained druggable oncogenes (ERBB2, MET, FGFR1, CDK6, PIK3R3 and PIK3CA), but at low individual patient prevalence. Genomic instability co-segregated with inactivation of DNA maintenance genes (BRCA1, BRCA2 or PALB2) and a mutational signature of DNA damage repair deficiency. Of 8 patients who received platinum therapy, 4 of 5 individuals with these measures of defective DNA maintenance responded.

Genomic and Genetic Characterization of Cholangiocarcinoma Identifies Therapeutic Targets for Tyrosine Kinase Inhibitors

BACKGROUND & AIMS Cholangiocarcinoma is a heterogeneous disease with a poor outcome that accounts for 5%-10% of primary liver cancers. We characterized its genomic and genetic features and associated these with patient responses to therapy. METHODS We profiled the transcriptomes from 104 surgically resected cholangiocarcinoma samples collected from patients in Australia, Europe, and the United States; epithelial and stromal compartments from 23 tumors were laser capture microdissected. We analyzed mutations in KRAS, epidermal growth factor receptor (EGFR), and BRAF in samples from 69 tumors. Changes in gene expression were validated by immunoblotting and immunohistochemistry; integrative genomics combined data from the patients with data from 7 human cholangiocarcinoma cell lines, which were then exposed to trastuzumab and lapatinib. RESULTS Patients were classified into 2 subclasses, based on 5-year survival rate (72% vs 30%; χ(2) = 11.61; P < .0007), time to recurrence (13.7 vs 22.7 months; P < .001), and the absence or presence of KRAS mutations (24.6%), respectively. Class comparison identified 4 survival subgroups (SGI-IV; χ(2) = 8.34; P < .03); SGIII was characterized by genes associated with proteasomal activity and the worst prognosis. The tumor epithelium was defined by deregulation of the HER2 network and frequent overexpression of EGFR, the hepatocyte growth factor receptor (MET), pRPS6, and Ki67, whereas stroma was enriched in inflammatory cytokines. Lapatinib, an inhibitor of HER2 and EGFR, was more effective in inhibiting growth of cholangiocarcinoma cell lines than trastuzumab. CONCLUSIONS We provide insight into the pathogenesis of cholangiocarcinoma and identify previously unrecognized subclasses of patients, based on KRAS mutations and increased levels of EGFR and HER2 signaling, who might benefit from dual-target tyrosine kinase inhibitors. The group of patients with the worst prognosis was characterized by transcriptional enrichment of genes that regulate proteasome activity, indicating new therapeutic targets.

Is concurrent radiation therapy required in patients receiving preoperative chemotherapy for adenocarcinoma of the oesophagus? A randomised phase II trial

INTRODUCTION Preoperative chemotherapy (CT) and preoperative chemoradiation therapy (CRT) for resectable oesophageal cancer have been shown to improve overall survival in meta-analyses. There are limited data comparing these preoperative therapies. We report the outcomes of a randomised phase II trial comparing preoperative CT and CRT for resectable adenocarcinoma of the oesophagus and gastro-oesophageal junction. METHODS Patients were randomised to receive preoperative CT with cisplatin (80 mg/m(2)) and infusional 5 fluorouracil (1000 mg/m(2)/d) on days 1 and 21, or preoperative CRT with the same drugs accompanied by concurrent radiation therapy commencing on day 21 of chemotherapy and the 5 fluorouracil reduced to 800 mg/m(2)/d. The radiation dose was 35 Gy in 15 fractions over 3 weeks. The endpoints were toxicity, response rates, resection (R) status, progression-free survival (PFS), overall survival (OS) and quality of life. RESULTS Seventy-five patients were enrolled on the study: 36 received preoperative CT and 39 preoperative CRT. Toxicity was similar for CT and CRT. Eight patients (11%) did not proceed to resection. The histopathological response rate (CRT 31% versus CT 8%, p = 0.01) and R1 resection rate (CRT 0% versus CT 11%, p = 0.04) favoured those receiving CRT. The median PFS was 14 and 26 months for CT and CRT respectively (p = 0.37). The median OS was 29 months for CT compared with 32 months for CRT (p = 0.83). CONCLUSIONS Despite no difference in survival, the improvement from preoperative CRT with respect to margin involvement makes this treatment a reasonable option for bulky, locally advanced resectable adenocarcinoma of the oesophagus.

Adenocarcinoma of the gastroesophageal junction: influence of esophageal resection margin and operative approach on outcome.

Objective:To determine whether the length of esophageal resection or the operative approach influences outcome for patients with adenocarcinoma of the gastroesophageal junction (GEJ). Summary Background Data:While R0 resection remains the mainstay of curative treatment of patients with GEJ cancer, the optimal length of esophageal resection remains controversial. Methods:Patients with Siewert I, II, or III adenocarcinoma who underwent complete gross resection without neoadjuvant therapy were identified from a prospectively maintained database. Proximal margin lengths were recorded ex vivo as the distance from the gross tumor edge to the esophageal transection line. Operative approaches were grouped into gastrectomy (limited esophagectomy) or esophagectomy (extended esophagectomy). Results:From 1985 through 2003, 505 patients underwent R0/R1 gastrectomy (n = 153) or esophagectomy (n = 352) without neoadjuvant treatment. There were no differences in R1 resection rate, number of nodes examined or operative mortality between gastrectomy and esophagectomy. Univariate analysis found >3.8 cm to be the ex vivo proximal margin length (approximately 5 cm in situ) most predictive of improved survival. Multivariable analysis in patients who underwent R0 resection with ≥15 lymph nodes examined (n = 275) found the number of positive lymph nodes, T stage, tumor grade, and ex vivo proximal margin length >3.8 cm to be independent prognostic factors. Subset analysis found that the benefit associated with >3.8 cm margin was limited to patients with T2 or greater tumors and ≤6 positive lymph nodes. Conclusions:In patients not receiving neoadjuvant therapy, the goal for patients with adenocarcinoma of the GEJ should be R0 resection including at least 15 lymph nodes, preferably with 5 cm of grossly normal in situ proximal esophagus for those with ≤6 positive lymph nodes. The operative approach may be individualized to achieve these goals.

Genomic catastrophes frequently arise in esophageal adenocarcinoma and drive tumorigenesis

Oesophageal adenocarcinoma (EAC) incidence is rapidly increasing in Western countries. A better understanding of EAC underpins efforts to improve early detection and treatment outcomes. While large EAC exome sequencing efforts to date have found recurrent loss-of-function mutations, oncogenic driving events have been underrepresented. Here we use a combination of whole-genome sequencing (WGS) and single-nucleotide polymorphism-array profiling to show that genomic catastrophes are frequent in EAC, with almost a third (32%, n = 40/123) undergoing chromothriptic events. WGS of 22 EAC cases show that catastrophes may lead to oncogene amplification through chromothripsis-derived double-minute chromosome formation (MYC and MDM2) or breakage-fusion-bridge (KRAS, MDM2 and RFC3). Telomere shortening is more prominent in EACs bearing localized complex rearrangements. Mutational signature analysis also confirms that extreme genomic instability in EAC can be driven by somatic BRCA2 mutations. These findings suggest that genomic catastrophes have a significant role in the malignant transformation of EAC.

Mutational signatures in esophageal adenocarcinoma define etiologically distinct subgroups with therapeutic relevance

Esophageal adenocarcinoma (EAC) has a poor outcome, and targeted therapy trials have thus far been disappointing owing to a lack of robust stratification methods. Whole-genome sequencing (WGS) analysis of 129 cases demonstrated that this is a heterogeneous cancer dominated by copy number alterations with frequent large-scale rearrangements. Co-amplification of receptor tyrosine kinases (RTKs) and/or downstream mitogenic activation is almost ubiquitous; thus tailored combination RTK inhibitor (RTKi) therapy might be required, as we demonstrate in vitro. However, mutational signatures showed three distinct molecular subtypes with potential therapeutic relevance, which we verified in an independent cohort (n = 87): (i) enrichment for BRCA signature with prevalent defects in the homologous recombination pathway; (ii) dominant T>G mutational pattern associated with a high mutational load and neoantigen burden; and (iii) C>A/T mutational pattern with evidence of an aging imprint. These subtypes could be ascertained using a clinically applicable sequencing strategy (low coverage) as a basis for therapy selection.

Health‐related quality of life among patients with adenocarcinoma of the gastro‐oesophageal junction treated by gastrectomy or oesophagectomy

Tumours of the gastro‐oesophageal junction may be resected by total gastrectomy (TG) or transthoracic oesophagectomy (TTO). This study compared health‐related quality of life (HRQL) following these procedures.

Meta-analysis of radical resection rates and margin assessment in pancreatic cancer

R0 resection rates (complete tumour removal with negative resection margins) in pancreatic cancer are 70–80 per cent when a 0‐mm margin is used, declining to 15–24 per cent with a 1‐mm margin. This review evaluated the R0 resection rates according to different margin definitions and techniques.

Hypermutation In Pancreatic Cancer

Pancreatic cancer is molecularly diverse, with few effective therapies. Increased mutation burden and defective DNA repair are associated with response to immune checkpoint inhibitors in several other cancer types. We interrogated 385 pancreatic cancer genomes to define hypermutation and its causes. Mutational signatures inferring defects in DNA repair were enriched in those with the highest mutation burdens. Mismatch repair deficiency was identified in 1% of tumors harboring different mechanisms of somatic inactivation of MLH1 and MSH2. Defining mutation load in individual pancreatic cancers and the optimal assay for patient selection may inform clinical trial design for immunotherapy in pancreatic cancer.