Biology versus terminology: East meets West in surgical pathology

Pathology of premalignant colorectal neoplasia

Colorectal cancer is a heterogeneous oncological disease that develops through several molecular pathways. Each pathway is associated with specific neoplastic precursor lesions. Classification of colorectal polyps and the molecular features of associated colorectal cancers have undergone significant changes. An understanding of colorectal carcinogenesis and the molecular features of colorectal carcinomas is now regarded as necessary for personalized treatment and management of patients with colon cancer, and even for patients undergoing screening colonoscopy for early detection and prevention of colorectal cancer. In the present review, we describe the pathological and molecular features of epithelial precursor lesions involved in the early phases of colorectal carcinogenesis.

Oxidative DNA damage and β-catenin expression in colorectal cancer evolution

PURPOSE

Oxidative DNA damage is one of the mechanisms associated to initial colorectal carcinogenesis, but how it interacts with β-catenin, an adherence protein related to cancer evolution, is not clear. This study investigates the relationship between oxidative DNA damage and β-catenin expression in normal mucosa and colon tumor tissue (adenoma and adenocarcinoma) in colorectal adenocarcinoma evolution.

METHOD

One hundred and 13 samples were studied. Hematoxylin-eosin determined histological grade. β-Catenin expression was analyzed by immunohistochemistry. The oxidative DNA damage was evaluated using comet assay technique. The coefficient for rejection of the nullity hypothesis was taken to 5 %. Kruskal-Wallis, Spearman test, and partial correlation were used to analyze the data.

RESULTS

There was oxidative DNA damage increase in colorectal cancer evolution (p < 0.01). Histological grade was correlated with oxidative DNA damage (p < 0.01). There were differences in β-catenin expression among normal, adenoma, and adenocarcinoma tissue with progressive increase of β-catenin expression (p < 0.00). Histological grade was correlated to β-catenin expression (p < 0.00). There was a relationship (p < 0.00) between β-catenin and histological grade while controlling for the effect of oxidative DNA damage.

CONCLUSION

The findings of this study make it possible to establish a relationship between oxidative DNA damage and β-catenin expression in normal mucosa and colorectal tumor tissue. Additionally, they show a causal relationship between variations of β-catenin in different tissues analyzed while controlling for the effect of oxidative DNA damage.

Comparisons of Gastric Cancer Treatments: East vs. West

There has been a large amount of speculation concerning the differences in the outcomes in patients who have gastric cancer in the Eastern and Western worlds. The differences in biology, surgical and adjuvant treatment have been used to explain such differences. There are clear differences observed in the histology (diffuse vs. intestinal), tumor location (proximal vs. distal), environmental exposures, dietary factors and Helicobacter pylori status. A higher incidence of gastric cancer in the East has led to screening programs, and leading to an earlier stage at presentation. Surgical treatment differs in that the extended lymph node dissection is routinely practiced in the Asian countries. Additionally, different adjuvant therapeutic regimens are used in both regions. The purpose of this review is to describe the differences in both presentation and treatment between the East and the West.

Efficacy of the revised Vienna Classification for diagnosing colorectal epithelial neoplasias

AIM: To prospectively investigate the efficacy of the revised Vienna Classification for diagnosing colorectal epithelial neoplastic lesions in cold biopsy specimens.

METHODS: Patients were selected for inclusion if they had colorectal epithelial lesions that were not considered suitable for direct endoscopic resection. These included colorectal polyps ≥ 10 mm and lesions suspected of being carcinomas capable of invading the colorectal submucosa or beyond, including strictures, based on the cold biopsies obtained from each lesion prior to resection. We investigated the relationship between diagnoses based on cold biopsy samples using the revised Vienna Classification and resected specimens of the same lesions, and the therapeutic implications of diagnoses made using the revised Vienna Classification. The same cold biopsy specimens were also examined using the Japanese Group Classification guidelines, and compared with the resected specimens of the same lesions for reference.

RESULTS: A total of 179 lesions were identified. The sensitivity, specificity, positive and negative predictive values of the revised Vienna Classification for distinguishing between intramucosal lesions and submucosal invasive carcinomas in cold biopsy specimens was 22.2%, 100%, 100%, and 71.4%, respectively, and for distinguishing between intramucosal lesions and those invading the submucosa or beyond was 59.7%, 100%, 100%, and 37.6%, respectively. The sensitivity, specificity, positive and negative predictive values of the Japanese Group Classification for distinguishing between intramucosal lesions and submucosal invasive carcinomas in cold biopsy specimens was 83.3%, 91.4%, 83.3%, and 91.4%, respectively, and for distinguishing between intramucosal lesions and those invading the submucosa or beyond was 95.1%, 91.4%, 97.9%, and 82.1%, respectively. A total of 137 of 144 carcinomas that had invaded the submucosa or beyond and three high-grade intraepithelial neoplasias were diagnosed as “carcinoma” using the Japanese Group Classification system.

CONCLUSION: The revised Vienna Classification for cold biopsy specimens has high positive predictive value in the diagnosis of colorectal carcinoma invasive to the submucosa or beyond.

Detection and treatment of early flat and depressed colorectal cancer using high-magnification chromoscopic colonoscopy: a change in paradigm for Western endoscopists?

Japanese researchers reported flat and depressed colorectal lesions in the 1980s. Such lesions were thought irrelevant to Western populations and described as "Phantom" or "Akitas" carcinoma. Many depressed neoplasms arise through the de novo pathogenic sequence and demonstrate early invasive characteristics. All investigators report difficulties in identifying flat and depressed lesions using conventional colonoscopy. Failure to detect and treat such lesions may be responsible for the current shortfalls in secondary colorectal cancer prevention. Given the introduction of colorectal cancer screening programs in the United Kingdom, Europe, and the United States, it is essential to re-evaluate the significance of flat lesions as applicable to Western cohorts and explore the safety and efficacy of new endoscopic technology and interventional therapeutics.

Endoscopic mucosal resection

Endoscopic mucosal resection (EMR) is a promising therapeutic option for removal of superficial carcinomas or premalignant lesions throughout the gastrointestinal tract. This review discusses indications and the several techniques of EMR in early tumors of esophagus, stomach, duodenum, and colon. EMR is not yet widely utilized in the West. However, great benefits may be obtained from this non-invasive technique after an accurate evaluation of patients and a careful staging of lesions that may assess the depth of infiltration and exclude the presence of lymph node metastases. EMR permits a complete removal of the lesion with histologic assessment of the entire specimen and the change in the pathologic stage in a significant number of patients. To minimize the risk of serious complications (mostly bleeding and perforation), only experienced endoscopists should undertake EMR in an appropriate environment. Data from literature are encouraging on the use of EMR, but a long-term follow-up of a large number of patients is necessary to confirm the effectiveness of this therapy.

Practical uses of chromoendoscopy and magnification at colonoscopy

New technologies in the form of high-magnification or zoom colonoscopy complemented by chromoscopic agents permits early detection of neoplastic colorectal lesions, particularly flat and depressed types. Establishing suitability for endoscopic resection or surgical excision can be enhanced using these techniques. Chromoscopic colonoscopy may play an important role in the routine endoscopic colorectal cancer surveillance programs in patients assuming a high risk of colorectal neoplasia. This article summarizes recent data regarding the prevalence and histopathologic characteristics of flat and depressed colorectal lesion in Western cohorts and describes how their detection and management can be improved by chromoscopy and magnification technology. The techniques required for chromoscopic colonoscopy and magnification imaging are outlined along with a review of the literature on these subjects.

The Vienna classification of gastrointestinal epithelial neoplasia

BACKGROUND

Use of the conventional Western and Japanese classification systems of gastrointestinal epithelial neoplasia results in large differences among pathologists in the diagnosis of oesophageal, gastric, and colorectal neoplastic lesions.

AIM

To develop common worldwide terminology for gastrointestinal epithelial neoplasia.

METHODS

Thirty one pathologists from 12 countries reviewed 35 gastric, 20 colorectal, and 21 oesophageal biopsy and resection specimens. The extent of diagnostic agreement between those with Western and Japanese viewpoints was assessed by kappa statistics. The pathologists met in Vienna to discuss the results and to develop a new consensus terminology.

RESULTS

The large differences between the conventional Western and Japanese diagnoses were confirmed (percentage of specimens for which there was agreement and kappa values: 37% and 0.16 for gastric; 45% and 0.27 for colorectal; and 14% and 0.01 for oesophageal lesions). There was much better agreement among pathologists (71% and 0.55 for gastric; 65% and 0.47 for colorectal; and 62% and 0.31 for oesophageal lesions) when the original assessments of the specimens were regrouped into the categories of the proposed Vienna classification of gastrointestinal epithelial neoplasia: (1) negative for neoplasia/dysplasia, (2) indefinite for neoplasia/dysplasia, (3) non-invasive low grade neoplasia (low grade adenoma/dysplasia), (4) non-invasive high grade neoplasia (high grade adenoma/dysplasia, non-invasive carcinoma and suspicion of invasive carcinoma), and (5) invasive neoplasia (intramucosal carcinoma, submucosal carcinoma or beyond).

CONCLUSION

The differences between Western and Japanese pathologists in the diagnostic classification of gastrointestinal epithelial neoplastic lesions can be resolved largely by adopting the proposed terminology, which is based on cytological and architectural severity and invasion status.