Survival outcomes used to validate version 9 of the American Joint Committee on Cancer staging system for appendiceal cancer.

The standard for cancer staging in the United States for all cancer sites, including primary carcinomas of the appendix, is the American Joint Committee on Cancer (AJCC) staging system. AJCC staging criteria undergo periodic revisions, led by a panel of site-specific experts, to maintain contemporary staging definitions through the evaluation of new evidence. Since its last revision, the AJCC has restructured its processes to include prospectively collected data because large data sets have become increasingly robust and available over time. Thus survival analyses using AJCC eighth edition staging criteria were used to inform stage group revisions in the version 9 AJCC staging system, including appendiceal cancer. Although the current AJCC staging definitions were maintained for appendiceal cancer, incorporating survival analysis into the version 9 staging system provided unique insight into the clinical challenges in staging rare malignancies. This article highlights the critical clinical components of the now published version 9 AJCC staging system for appendix cancer, which (1) justified the separation of three different histologies (non-mucinous, mucinous, signet-ring cell) in terms of prognostic variance, (2) demonstrated the clinical implications and challenges in staging heterogeneous and rare tumors, and (3) emphasized the influence of data limitations on survival analysis for low-grade appendiceal mucinous neoplasms.

Overall Survival is More Closely Associated with Peritoneal than Primary Appendiceal Pathological Grade in Pseudomyxoma Peritonei with Discordant Pathology.

BACKGROUND: The WHO classification of mucinous appendix neoplasms and pseudomyxoma peritonei (PMP) describes low- and high-grade histology and is of prognostic importance. The metastatic peritoneal disease grade can occasionally be different from the primary appendix tumor. This analysis aimed to report outcomes from a high-volume center in patients with pathological discordance. METHODS: This was a retrospective analysis of prospective data of patients treated by cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for PMP at a single institution between January 2016 and December 2020. Reporting was by pathologists with a special interest in peritoneal malignancy. Discordant pathology was classified as a low-grade primary appendix tumor with high-grade peritoneal disease, or a high-grade primary appendix tumor with low-grade peritoneal disease. Outcomes analyzed were overall and recurrence-free survival, and Kaplan-Meier survival curves and the log-rank test were used to analyze the outcomes. RESULTS: Between 2016 and 2020, 830 patients underwent CRS and HIPEC for PMP, of whom 37 (4.4%) had discordant pathology. The primary appendix tumors were low-grade in 23 patients and high-grade in 14 patients. The median Peritoneal Cancer Index (PCI) was significantly higher in patients with a low-grade primary tumor (31 vs. 16; p = 0.001), while complete cytoreduction (CC0/1) was achieved in 31/37 (83.8%) patients. The median follow-up was 19 months. Overall survival was worse in those with high-grade peritoneal disease (p = 0.029), whereas recurrence-free survival was similar in both groups (p = 0.075). CONCLUSION: In PMP with pathological discordance, the peritoneal disease grade influences prognosis and survival.

Patients undergoing cytoreductive surgery for peritoneal malignancy of appendiceal origin should be consented for umbilical excision as 30% have umbilical infiltration.

AIM: Cytoreductive surgery (CRS) for peritoneal malignancy has traditionally included umbilical excision with no published evidence on the incidence of umbilical involvement. The primary aim of this work was to determine the incidence of umbilical involvement in patients undergoing CRS for peritoneal malignancy of appendiceal origin. The secondary aim was to investigate the relationship of umbilical involvement with prior surgery affecting the umbilicus, such as diagnostic laparoscopy and midline laparotomy. METHOD: This study is from a national referral centre in the United Kingdom for appendiceal tumours and peritoneal malignancy. It is a retrospective analysis from a dedicated prospective database. We evaluated the most recent 200 consecutive patients who underwent CRS for peritoneal malignancy of appendiceal origin where all pathology specimens were reported by a recognized expert pathologist in appendiceal tumours and peritoneal malignancy. RESULTS: From June 2016 to September 2019, 200 consecutive patients had CRS and 178 had umbilical excision. Of these 54/178 (30.3%) had disease involving the umbilicus. The pathological findings in the 178 patients were low-grade mucinous carcinoma peritonei in 90/178 (50.6%), high-grade mucinous carcinoma peritonei in 31/178 (17.4%), metastatic appendiceal adenocarcinoma in 29/178 (16.4%) and diffuse acellular mucin in 28/178 (15.7%). Umbilical involvement was found in 25/90 (27.8%) with low-grade, 11/31 (35.5%) with high-grade, 8/29 (27.6%) with adenocarcinoma and 10/28 (35.7%) of patients with acellular mucin. In the 54 patients with umbilical disease, 30/54 (55.6%) had previous diagnostic surgery affecting the umbilicus. In the 124 patients without umbilical disease, 76/124 (61.2%) had prior surgery involving the umbilicus. The difference between the groups was not significant (p = 0.24). CONCLUSION: In patients with peritoneal malignancy of appendiceal origin, approximately 30% have umbilical involvement, irrespective of the primary appendiceal pathology. Umbilical involvement was not associated with prior surgery involving the umbilicus. This is the first report to document the incidence of umbilical pathology and supports consideration of routine umbilical excision in CRS for peritoneal malignancy.

Complicated appendiceal diverticulosis versus low-grade appendiceal mucinous neoplasms: a major diagnostic dilemma.

AIMS: To research and identify how often complicated diverticular disease of the appendix [appendiceal diverticular disease (ADD)] shows histological mimicry of low-grade appendiceal mucinous neoplasms (LAMNs) and to provide guidance on the useful histopathological features that allow the appropriate diagnosis to be made. METHODS AND RESULTS: Seventy-four cases of complicated appendiceal diverticular disease were identified from two specialist centres. Of the second opinion/consultation cases, 71% of the ADD cases had been diagnosed by referring pathologists as LAMNs. Salient pathological features were identified and agreed upon to reach the applicable diagnosis. For a diagnosis of complicated diverticulosis, particularly when associated with mucus cysts, the following morphological features were regarded as important: relative retention of the normal mucosal architecture with lamina propria and a maintained crypt architecture, crypts arranged in regular array, epithelial hyperplasia and a lack of nuclear abnormalities extending the length of the crypts. In a formal case-control study undertaken on 30 cases with each diagnosis, ADD and LAMN, loss of lamina propria, a filiform architecture and hypermucinosis were significantly associated with low-grade appendiceal mucinous neoplasms. Mucosal neuromas were significantly associated with diverticular disease of the appendix. CONCLUSIONS: To our knowledge, this study represents the largest series in the world literature and serves to highlight the important pathological features to distinguish complicated diverticular disease of the appendix from LAMNs, and emphasises the difficulties experienced by diagnostic pathologists in diagnosing complicated appendiceal diverticulosis. This is important, as LAMNs have a significant risk of transcoelomic spread, while complicated appendiceal diverticulosis has no such risk.

Reproducibility of the peritoneal regression grading score for assessment of response to therapy in peritoneal metastasis.

AIMS: The four-tiered peritoneal regression grading score (PRGS) assesses the response to chemotherapy in peritoneal metastasis (PM). The PRGS is used, for example, to assess the response to pressurised intraperitoneal aerosol chemotherapy (PIPAC). However, the reproducibility of the PRGS is currently unknown. We aimed to evaluate the inter- and intraobserver variability of the PRGS. METHODS AND RESULTS: Thirty-three patients who underwent at least three PIPAC treatments as part of the PIPAC-OPC1 or PIPAC-OPC2 clinical trials at Odense University Hospital, Denmark, were included. Prior to each therapy cycle, peritoneal quadrant biopsies were obtained and three haematoxylin and eosin (H&E)-stained step sections were scanned and uploaded to a pseudonymised web library. For determining interobserver variability, eight pathologists assessed the PRGS for each quadrant biopsy, and Krippendorff's alpha and intraclass correlation coefficients (ICCs) were calculated. For determining intraobserver variability, three pathologists repeated their own assessments and Cohen's kappa and ICCs were calculated. A total of 331 peritoneal biopsies were analysed. Interobserver variability for PRGS of each biopsy and for the mean and maximum PRGS per biopsy set was moderate to good/substantial. The intraobserver variability for PRGS of each biopsy and for the mean and maximum PRGS per biopsy set was good to excellent/almost perfect. CONCLUSIONS: Our data support the PRGS as a reproducible and useful tool to assess response to intraperitoneal chemotherapy in PM. Future studies should evaluate the prognostic and predictive role of the PRGS.

Diagnostic and therapeutic laparoscopy in assessment and management of patients with appendiceal neoplasms.

INTRODUCTION: Radiological imaging often underestimates the extent of low volume peritoneal disease. The benefit of laparoscopy in assessing peritoneal metastases from colorectal and gastric cancer is accepted, but is inconclusive for appendiceal malignancy. We report our experience of diagnostic (DL) and therapeutic laparoscopy (TL) in patients with appendiceal tumours to determine indications and role in assessment and management. METHODS: A retrospective review of a National Peritoneal Malignancy Centre's prospectively maintained database was performed. All patients with appendiceal neoplasms who underwent DL or TL between September 2011 and January 2016 were included. The indications and outcomes of the laparoscopy, complications and interval to laparotomy were evaluated. RESULTS: Six hundred and eighty-five patients underwent surgery for appendiceal neoplasms during the study period, of which 73 (10.6%) underwent laparoscopy (50 DL, 23 TL). The main indications for DL were to clarify imaging and stage patients with high-risk histology. Indications for TL were an abnormal appendix without gross pseudomyxoma peritonei (PMP) or with low volume PMP, and concerns for fertility in the presence of PMP. DL resulted in 16 patients (32%) avoiding laparotomy because of extensive disease or no tumour found. Overall, 28 patients were assessed to have resectable disease and at laparotomy, 25/28 had complete cytoreduction with three patients unresectable. In the TL group, appendicectomy and peritoneal lavage was achieved in all four women with fertility concerns, allowing them to conceive thereafter. There were no complications. CONCLUSIONS: Patients with high-risk appendiceal neoplasm may benefit from DL, and potentially avoid unnecessary laparotomy. TL is useful in patients with low volume PMP and may aid fertility in selected patients.

The histopathological classification, diagnosis and differential diagnosis of mucinous appendiceal neoplasms, appendiceal adenocarcinomas and pseudomyxoma peritonei.

The vermiform appendix is the primary site of several distinctive benign and malignant neoplasms. Some can produce the clinical syndrome of pseudomyxoma peritonei (PMP). A consensus on their terminology was reached by an international panel of pathologists and clinicians working under the auspices of the Peritoneal Surface Oncology Group International (PSOGI), and this review discusses the application of the PSOGI classification to routine reporting. We discuss diagnosis and differential diagnosis together with implications for patient management, covering low-grade appendiceal mucinous neoplasms, high-grade appendiceal mucinous neoplasms, serrated polyps, adenomas and adenocarcinomas. We do not cover goblet cell tumours or neuroendocrine neoplasms in this paper.

Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy: an emerging treatment option for advanced goblet cell tumors of the appendix.

BACKGROUND: The debate remains whether appendiceal goblet cell cancers behave as classical carcinoid or adenocarcinoma. Treatment options are unclear and reports of outcomes are scarce. Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS+HIPEC) is considered optimal treatment for peritoneal involvement of other epithelial appendiceal tumors. METHODS: Prospective cohorts of patients treated for advanced appendiceal tumors from three peritoneal malignancy centres were collected (1994-2011). All patients underwent complete CRS+HIPEC, when possible, or tumor debulking. Demographic and outcome data for patients with goblet cell cancers were compared to patients with low- or high-grade epithelial appendiceal tumors treated during the same time period. RESULTS: Details on 45 goblet cell cancer patients were compared to 708 patients with epithelial appendix lesions. In the goblet cell group, 57.8 % were female, median age was 53 years, median peritoneal cancer index (PCI) was 24, and CRS+HIPEC was achieved in 71.1 %. These details were similar in patients with low- or high-grade epithelial tumors. Lymph nodes were involved in 52 % of goblet cell patients, similar to rates in high-grade cancers, but significantly higher than in low-grade lesions (6.4 %; p < 0.001). At 3 years, overall survival (OS) was 63.4 % for goblet cell patients, intermediate between that for high-grade (40.4-52.2 %) and low-grade (80.6 %) tumors. On multivariate analysis, tumor histology, PCI, and achievement of CRS+HIPEC were independently associated with OS. CONCLUSIONS: This data supports the concept that appendiceal goblet cell cancers behave more as high-grade adenocarcinomas than as low-grade lesions. These patients have reasonable long-term survival when treated using CRS+HIPEC, and this strategy should be considered.

High-Grade Appendiceal Mucinous Neoplasm: Clinicopathologic Findings in 35 Cases.

CONTEXT.­: High-grade appendiceal mucinous neoplasm (HAMN) is a relatively recently introduced term describing a rare epithelial neoplasm of the appendix that demonstrates pushing-type invasion but high-grade cytologic atypia. It remains understudied. OBJECTIVE.­: To describe clinicopathologic features of HAMNs. DESIGN.­: We identified 35 HAMNs in a multi-institutional retrospective study. Clinical and histologic features were reviewed in all cases, as well as molecular features in 8 cases. RESULTS.­: Patients were 57 years of age on average and most commonly presented with abdominal/pelvic pain. Histologically, 57% of the tumors showed widespread high-grade features. Architectural patterns in high-grade areas included flat, undulating, or villous growth, and occasionally micropapillary, cribriform, or multilayered growth. Thirteen cases had intact serosa, and the remaining 22 perforated the serosa, including 7 with peritoneal acellular mucin beyond appendiceal serosa and 10 with grade 2 pseudomyxoma peritonei. Molecular abnormalities included KRAS mutations in 7 cases and TP53 mutations in 4. No tumor confined to the appendix recurred. Two patients without pseudomyxoma peritonei at initial presentation developed pseudomyxoma on follow-up. Among 11 patients who presented with pseudomyxoma peritonei, 5 died of disease and 3 were alive with disease at last follow-up. CONCLUSIONS.­: HAMNs have a similar presentation to low-grade appendiceal mucinous neoplasm, and similar stage-based prognosis. When they spread to the peritoneum, they typically produce grade 2 pseudomyxoma peritonei, which may be associated with a worse prognosis than classical grade 1 pseudomyxoma peritonei.

Relationship between loneliness and proangiogenic cytokines in newly diagnosed tumors of colon and rectum.

OBJECTIVE: To investigate the association of serum levels of proangiogenic cytokines with different indices of social support and loneliness by measuring the levels of expression of two important proangiogenic cytokines, vascular endothelial growth factor (VEGF), and interleukin-6 in tumors of colon and rectum. Lack of social support has been prospectively associated with cancer progression. METHODS: Fifty-one newly diagnosed patients with colorectal tumors (mean age, 68.3 years) completed two measures of loneliness 1 to 2 days before their surgical treatment. The first was an explicit self-report questionnaire, which tapped into negative feelings as a result of low social support. The second was a standardized computer-based task, which measured loneliness implicitly. Immunohistochemical analyses were performed on tumor tissues post surgery to determine the expression of cytokines. RESULTS: Logistic regression showed that higher levels of implicit loneliness independently predicted stronger expression of VEGF, controlling for Dukes stage and explicit loneliness, both of which were nonsignificant predictors. No significant relationships were found between the loneliness measures and interleukin-6. CONCLUSIONS: The results of this study suggest VEGF to be an angiogenic mechanism through which loneliness may lead to worse cancer-related outcomes. Implications are discussed in terms of devising targeted psychosocial and immunotherapeutic interventions for cancer patients with low social support.

Updates in Appendix Pathology: The Precarious Cutting Edge.

Mucinous appendiceal tumors include low-grade appendiceal mucinous neoplasm, high-grade appendiceal mucinous neoplasm, and mucinous adenocarcinoma. Nonmucinous adenocarcinomas are less frequent. Recent consensus guidelines and the latest edition of the World Health Organization classification will allow consistent use of agreed nomenclature. Accurate diagnosis is important not only for patient management but also to allow comparison of results between centers and tumor registries. Serrated polyps are the most common benign polyp in the appendix. They need to be distinguished from low-grade appendiceal mucinous neoplasm, which can also mimic other benign conditions. Goblet cell adenocarcinomas are a distinctive type of appendiceal neoplasm.

Delivering a pathology curriculum in an integrated medical course.

Modern integrated medical curricula usually do not include a separate pathology course. Consequently, there is a risk that important pathological principles may be omitted. We aimed to ensure that pathology is properly represented by developing a core pathology curriculum created in consultation with local pathologists. Appropriate information technology to track the delivery of this material within the integrated curriculum structure was developed using a learning content management system in which a metadata schema was constructed. This allows a sophisticated view of where and how pathology appears in the course and can also increase the visibility of the subject by demonstrating the central place of pathology in medicine. In conclusion, a core curriculum in pathology that can be tracked by information technology with sufficient power and flexibility is a solution to the potential loss of pathology from integrated medical courses. We believe the result is superior to a stand-alone pathology course.

Single centre guidelines for radiological follow-up based on 775 patients treated by cytoreductive surgery and HIPEC for appendiceal pseudomyxoma peritonei.

AIM: Pseudomyxoma peritonei (PMP) is an uncommon malignancy, generally originating from a ruptured epithelial tumour of the appendix. Despite successful cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC), some patients recur. Currently there are no guidelines on the methods, frequency and intensity of follow-up. METHODS: Between 1994 and 2016, 1070 patients underwent surgery for a perforated epithelial tumour of the appendix, predominantly with PMP. Overall (OS) and Disease Free Survival (DFS) were documented by annual CT scanning and evaluated according to the Kaplan-Meier method. The influence of histological differentiation was investigated. RESULTS: Overall, 775/1070 (72%) had complete cytoreductive surgery (CCRS) and HIPEC. Histological classification was low grade PMP in 615 (79.4%), high grade PMP in 134 (17.3%) and adenocarcinoma in 26 (3.4%). DFS and OS were significantly worse for high grade disease, with the steepest decline for both in the first three years. DFS curves, for low as well as high grade PMP, levelled off at year 6 at approximately 60% and 20% respectively. Thereafter there were few recurrences in either group. CONCLUSION: Annual CT of the abdomen and pelvis in the first six years appears to be adequate follow-up for low grade PMP. In high grade PMP, additional imaging of the chest and more frequent surveillance, during the first three years postoperatively, may detect recurrent disease earlier. From year 6 on, reduced frequency of follow-up is proposed, independent of the histology. This long-term follow-up in a large number of patients gives insight into tumour behavior after CCRS and HIPEC for PMP and guides intensity of surveillance.

Pathophysiology and classification of pseudomyxoma peritonei.

Background: The term pseudomyxoma peritonei (PMP) was first described in 1884 and there has been much debate since then over the term. A recent consensus of world experts agreed that PMP should be thought of as a clinical entity characterised by the presence of mucinous ascites, omental cake, peritoneal implants and possibly ovarian involvement. It generally originates from mucinous appendiceal tumours. Content: This review details the clinical presentation of this unusual condition, presents the new classification system and how this relates to outcome. The pathophysiology of this disease is also explored with a special reference to the relationship of the disease to tumour markers. Summary: A classification system has been agreed upon by the leading experts in PMP which is now divided into low and high grade mucinous carcinomatosis peritonei. This distinction correlates with clinical outcome as does the presence of raised tumour markers preoperatively. Outlook: Research needs to be focused on understanding the factors associated with poor prognosis through well designed multi-centred prospective studies. This will allow us to identify patients with bad tumour biology so that targeted treatment based on likely prognosis may then become a reality.

Peritoneal sampling and histological assessment of therapeutic response in peritoneal metastasis: proposal of the Peritoneal Regression Grading Score (PRGS).

Background: Multimodal therapeutic strategies have improved the outcome of peritoneal metastases (PM). However, objective assessment of therapy response remains difficult in PM, since radiological studies have a poor accuracy for low-volumetric disease. There is an obvious need for a histological gold standard allowing assessment of tumor response to treatment in PM. Content: We propose to perform peritoneal punch biopsies with a diameter of 3 to 5 mm in all four abdominal quadrants. We propose a four-tier Peritoneal Regression Grading Score (PRGS), defined as Grade 1: complete response (absence of tumor cells), Grade 2: major response (major regression features, few residual tumor cells), Grade 3: minor response (some regressive features but predominance of residual tumor cells), Grade 4: no response (tumor cells without any regressive features). Acellular mucin and infarct-like necrosis should be regarded as regression features. We recommend reporting the mean and the worst value of the regression grades obtained. When complete tumor response is suspected intraoperatively, a peritoneal cytology should be sampled. Summary: A generic, unique score for the assessment of histological tumor response to chemotherapy in PM makes sense because of the clinical impact of histological response to therapy and because the organ of metastasis (peritoneum) is the same. By adopting PRGS, different centers will be able to use a uniform terminology and grading that will allow meaningful comparison of their results. Outlook: PRGS has now to be validated in several gastrointestinal and gynecological cancer types and may be useful both in clinical and research settings.

A comparison of formalin and GEWF in fixation of colorectal carcinoma specimens: rates of lymph node retrieval and effect on TNM staging.

AIMS: The Royal College of Pathologists recommend that a median of at least 12 lymph nodes should be harvested during pathological staging of colorectal cancer. It is not always easy to harvest the required number, especially in patients with rectal cancer receiving neoadjuvant therapy. Lymph node revealing solutions, for example, GEWF, may improve nodal yield. GEWF is safe, cheap and easy to use. METHODS: In a controlled trial, lymph node yields were compared after secondary specimen dissection following either 24 h of further fixation in formalin (n=101) or GEWF immersion (n=99). The number, size and tumour status of additional lymph nodes identified were compared between groups. Twenty-seven cases that received long-course neoadjuvant therapy were also assessed. RESULTS: Median lymph node yield at primary dissection met national standards overall (19) but also in the long-course neoadjuvant therapy group (13). Lymph nodes were smaller in neoadjuvant cases compared with non-neoadjuvant cases (mean size range 1.3-5.6 mm vs 1.5-8.9 mm). The use of further fixation and GEWF detected more nodes at secondary dissection. The mean number of additional nodes harvested was greater with formalin (8.3) than GEWF (7.3). There was no significant difference in the mean size of the additional lymph nodes detected between groups (point estimate 1.02; 95% CI -0.58 to 2.63; p=0.211). Upstaging triggering adjunct chemotherapy occurred in 1% (2/200) of cases. CONCLUSIONS: The routine use of adjunct techniques to identify additional lymph nodes is unnecessary with underlying high-quality dissection practice. Emphasis should be placed upon education and training, spending appropriate time dissecting and ensuring specimens are sufficiently fixed beforehand.

A Consensus for Classification and Pathologic Reporting of Pseudomyxoma Peritonei and Associated Appendiceal Neoplasia: The Results of the Peritoneal Surface Oncology Group International (PSOGI) Modified Delphi Process.

Pseudomyxoma peritonei (PMP) is a complex disease with unique biological behavior that usually arises from appendiceal mucinous neoplasia. The classification of PMP and its primary appendiceal neoplasia is contentious, and an international modified Delphi consensus process was instigated to address terminology and definitions. A classification of mucinous appendiceal neoplasia was developed, and it was agreed that "mucinous adenocarcinoma" should be reserved for lesions with infiltrative invasion. The term "low-grade appendiceal mucinous neoplasm" was supported and it was agreed that "cystadenoma" should no longer be recommended. A new term of "high-grade appendiceal mucinous neoplasm" was proposed for lesions without infiltrative invasion but with high-grade cytologic atypia. Serrated polyp with or without dysplasia was preferred for tumors with serrated features confined to the mucosa with an intact muscularis mucosae. Consensus was achieved on the pathologic classification of PMP, defined as the intraperitoneal accumulation of mucus due to mucinous neoplasia characterized by the redistribution phenomenon. Three categories of PMP were agreed-low grade, high grade, and high grade with signet ring cells. Acellular mucin should be classified separately. It was agreed that low-grade and high-grade mucinous carcinoma peritonei should be considered synonymous with disseminated peritoneal adenomucinosis and peritoneal mucinous carcinomatosis, respectively. A checklist for the pathologic reporting of PMP and appendiceal mucinous neoplasms was also developed. By adopting the classifications and definitions that were agreed, different centers will be able to use uniform terminology that will allow meaningful comparison of their results.

Near peer teaching in medical curricula: integrating student teachers in pathology tutorials.

INTRODUCTION: Due to increased cognitive and social congruence with their tutees, near peer teachers (NPTs) may be capable of more effectively delivering course material. This study examines NPTs as pathology tutors alongside more traditional teachers (e.g., consultants and registrars) to explore their acceptability, effectiveness, and years of 'distance' between tutors and tutees. METHOD: In total, 240 first- and second-year undergraduate medical students were taught set material in a pathology tutorial setting by NPTs (fourth-year medical students), registrars, or consultants. Learners were then asked to provide feedback using a 15-item, Likert-type scale. RESULTS: On 11 of the 15 items, there were no significant differences in students' median ratings. However, NPTs were perceived to be significantly more approachable than consultants, more aware of learning outcomes, more receptive to student input, and more invested in exam success. Compared with second-year students, first-year students showed a preference towards registrar tutors in terms of perceived gain of knowledge and use of time. In contrast, second-year students showed a preference towards NPTs, who provided more perceived knowledge gain and investment in exam success. No significant differences were found regarding consultant tutors. DISCUSSION: Perhaps due to increased congruence with tutees, NPTs show promise as tutors within medical curricula. This provides advantages not only to tutees, but also to tutors - who may gain vital teaching experience and offer an effective supplement to 'traditional' faculty educators.

Epithelial neoplasms of the appendix and colorectum: an analysis of cell proliferation, apoptosis, and expression of p53, CD44, bcl-2.

CONTEXT: Carcinomas of the appendix are usually well-differentiated mucinous adenocarcinomas that tend to produce pseudomyxoma peritonei and do not show metastatic spread until late in the disease process. In contrast, adenocarcinomas of the colon and rectum rarely result in pseudomyxoma peritonei and frequently metastasize, even if mucinous and well differentiated. These differences in behavior may be reflected by differences at the molecular level. OBJECTIVES: To examine adenocarcinomas and their precursor lesions (adenomas) of the appendix and colorectum and to determine whether differences exist in the numbers of proliferating and apoptotic cells or in expression of p53, bcl-2, and the standard form of CD44 (CD44s). DESIGN: Retrospective analysis of surgical specimens. SETTING: Multicenter study. PATIENTS: Individuals treated surgically for tumors of the appendix or colorectum. INTERVENTIONS: Sections were cut from formalin-fixed surgical specimens and immunohistochemical tests were performed for Ki-67 (as a marker of proliferating cells), M30 (as a marker of apoptotic cells), p53, CD44s, and bcl-2. MAIN OUTCOME MEASURES: Expression of Ki-67, M30, p53, CD44s, and bcl-2 in tumor cells. RESULTS: The appendiceal adenomas showed significantly lower Ki-67 counts, p53 expression, and bcl-2 expression. When compared with adenocarcinomas of the colorectum in general (mucinous and nonmucinous), the appendiceal adenocarcinomas showed significantly lower Ki-67 counts, M30 counts, and CD44s expression. However, when the analysis was confined to well-differentiated mucinous adenocarcinomas, only the M30 count was significantly different. CONCLUSIONS: The lower proliferative and apoptotic activity of appendiceal carcinomas and the lower CD44s expression are in keeping with their more indolent behavior compared with adenocarcinomas of the colorectum. However, when only the subset of well-differentiated mucinous adenocarcinomas was compared, only the apoptotic activity was different, suggesting that the other differences were related to the morphologic structure of the lesions.