Extent of Resection and Long-Term Outcomes for Appendiceal Adenocarcinoma: a SEER Database Analysis of Mucinous and non-Mucinous Histologies

BACKGROUND

Mucinous appendiceal adenocarcinomas (MAA) and non-mucinous appendiceal adenocarcinomas (NMAA) demonstrate differences in rates and patterns of recurrence, which may inform the appropriate extent of surgical resection (i.e., appendectomy versus colectomy). The impact of extent of resection on disease-specific survival (DSS) for each histologic subtype was assessed.

PATIENTS AND METHODS

Patients with resected, non-metastatic MAA and NMAA were identified in the Surveillance, Epidemiology, and End Results database (2000-2020). Multivariable models were created to examine predictors of colectomy for each histologic subtype. DSS was calculated using Kaplan-Meier estimates and examined using Cox proportional hazards modeling.

RESULTS

Among 4674 patients (MAA: n = 1990, 42.6%; NMAA: n = 2684, 57.4%), the majority (67.8%) underwent colectomy. Among colectomy patients, the rate of nodal positivity increased with higher T-stage (MAA: T1: 4.6%, T2: 4.0%, T3: 17.1%, T4: 21.6%, p < 0.001; NMAA: T1: 6.8%, T2: 11.4%, T3: 25.6%, T4: 43.8%, p < 0.001) and higher tumor grade (MAA: well differentiated: 7.7%, moderately differentiated: 19.2%, and poorly differentiated: 31.3%; NMAA: well differentiated: 9.0%, moderately differentiated: 20.5%, and 44.4%; p < 0.001). Nodal positivity was more frequently observed in NMAA (27.6% versus 16.4%, p < 0.001). Utilization of colectomy was associated with improved DSS for NMAA patients with T2 (log rank p = 0.095) and T3 (log rank p = 0.018) tumors as well as moderately differentiated histology (log rank p = 0.006). Utilization of colectomy was not associated with improved DSS for MAA patients, which was confirmed in a multivariable model for T-stage, grade, and use of adjuvant chemotherapy [hazard ratio (HR) 1.00, 95% confidence interval (CI) 0.81-1.22].

CONCLUSIONS

Colectomy was associated with improved DSS for patients with NMAA but not MAA. Colectomy for MAA may not be required.

Mortality risk prediction for primary appendiceal cancer

BACKGROUND

Accurately predicting survival in patients with cancer is crucial for both clinical decision-making and patient counseling. The primary aim of this study was to generate the first machine-learning algorithm to predict the risk of mortality following the diagnosis of an appendiceal neoplasm.

METHODS

Patients with primary appendiceal cancer in the Surveillance, Epidemiology, and End Results database from 2000 to 2019 were included. Patient demographics, tumor characteristics, and survival data were extracted from the Surveillance, Epidemiology, and End Results database. Extreme gradient boost, random forest, neural network, and logistic regression machine learning models were employed to predict 1-, 5-, and 10-year mortality. After algorithm validation, the best-performance model was used to develop a patient-specific web-based risk prediction model.

RESULTS

A total of 16,579 patients were included in the study, with 13,262 in the training group (80%) and 3,317 in the validation group (20%). Extreme gradient boost exhibited the highest prediction accuracy for 1-, 5-, and 10-year mortality, with the 10-year model exhibiting the maximum area under the curve (0.909 [±0.006]) after 10-fold cross-validation. Variables that significantly influenced the predictive ability of the model were disease grade, malignant carcinoid histology, incidence of positive regional lymph nodes, number of nodes harvested, and presence of distant disease.

CONCLUSION

Here, we report the development and validation of a novel prognostic prediction model for patients with appendiceal neoplasms of numerous histologic subtypes that incorporate a vast array of patient, surgical, and pathologic variables. By using machine learning, we achieved an excellent predictive accuracy that was superior to that of previous nomograms.

Mucinous appendiceal neoplasms: Report of a case and brief literature review

INTRODUCTION

Appendiceal tumors are rare neoplasms detected in about 2 % of appendicectomies. The clinical presentation is often unspecific, varying from unspecific abdominal pain or presenting as an acute appendicitis or being asymptomatic.

CASE PRESENTATION

We present a case of a patient presenting as an acute appendicitis with a mucocele, and then classified as HAMN. The patient was treated with initial laparoscopic approach and then conversion in laparotomy with appendectomy. Histology demonstrated a high grade appendiceal mucinous neoplasm limited to submucosa (pT3), with concomitant acute phlegmonous appendicitis. The patient was subsequently sent to a referral center where a right hemicolectomy with HIPEC was performed.

DISCUSSION

HAMN is a rare entity, only recently classified as a new kind of appendiceal mucinous neoplasm. Due to the supposed higher aggressivity, HAMN must be treated as an appendiceal adenocarcinoma. The treatment of this rare entity is not yet well standardized, because of the rarity of this disease.

CONCLUSION

HAMN is a very rare tumor. In the emergency setting, it is mandatory to avoid rupture of the appendix, to minimize the risk of developing pseudomyxoma peritonei. Pathology is essential for further decisions in these patients and plays a very important role in treatment and prognosis.

Prevalence of, Subtypes of, and the Role of Age in Incidental Appendiceal Neoplasms in Acute Appendicitis: A Single-Institute Study from Bahrain

INTRODUCTION

Primary appendiceal neoplasms (ANs) are rare entities that can present with acute appendicitis symptoms. Accurate diagnosis of these diverse subtypes is crucial for prognosis and proper management.

AIMS AND OBJECTIVES

 This descriptive retrospective study aims to determine the prevalence and pathological subtypes of incidental ANs in patients presenting with acute appendicitis symptoms at Salmaniya Medical Center (SMC) in Bahrain between the period of January 2020 and March 2024. Particular focus was placed on investigating whether advanced age is a significant risk factor for these neoplasms.

MATERIALS AND METHODS

 The study included 38,643 patients (aged 15 years and above) who underwent appendectomy for suspected acute appendicitis during the study period. Demographic data, clinical diagnoses, preoperative imaging findings, histopathological reports, and management details were analyzed. Medical records of patients were retrieved from ISEHA system. Statistical analysis was done using Microsoft Excel.

RESULTS

The results showed that 12 patients (0.04% per year) had different subtypes of appendiceal tumors. Neuroendocrine tumors were the most common, identified in nine patients (75%), including nine cases of well-differentiated neuroendocrine carcinoma (NEC). Other histopathological subtypes included low-grade appendiceal mucinous neoplasm (LAMN), adenocarcinoma, and goblet cell adenocarcinoma, each found in one patient. Additionally, two patients had confirmed appendiceal mucocele. The mean age of patients with ANs was 30 years (range: 19-52 years), and 66.6% were younger than 38 years.  Conclusion: These findings highlight the importance of considering ANs in the differential diagnosis of acute appendicitis, especially in older patients. Further research is warranted to confirm the role of age as a risk factor and guide clinical decision-making.

Sufficient Regional Lymph Node Examination for Staging Adenocarcinoma of the Appendix

BACKGROUND

The presence of lymph node (LN) metastasis is a known negative prognostic factor in appendix cancer (AC) patients. However, currently the minimum number of LNs required to adequately determine LN negativity is extrapolated from colorectal studies and data specific to AC is lacking. We aimed to define the lowest number of LNs required to adequately stage AC and assess its impact on oncologic outcomes.

METHODS

Patients with stage II-III AC from the National Cancer Database (NCDB 2004-2019) undergoing surgical resection with complete information about LN examination were included. Multivariable logistic regression assessed the odds of LN positive (LNP) disease for different numbers of LNs examined. Multivariable Cox regressions were performed by LN status subgroups, adjusted by prognostic factors, including grade, histologic subtype, surgical approach, and documented adjuvant systemic chemotherapy.

RESULTS

Overall, 3,602 patients were included, from which 1,026 (28.5%) were LNP. Harvesting ten LNs was the minimum number required without decreased odds of LNP compared with the reference category (≥ 20 LNs). Total LNs examined were < 10 in 466 (12.9%) patients. Median follow-up from diagnosis was 75.4 months. Failing to evaluate at least ten LNs was an independent negative prognostic factor for overall survival (adjusted hazard ratio 1.39, p < 0.01).

CONCLUSIONS

In appendix adenocarcinoma, examining a minimum of ten LNs was necessary to minimize the risk of missing LNP disease and was associated with improved overall survival rates. To mitigate the risk of misclassification, an adequate number of regional LNs must be assessed to determine LN status.

Incidence trends and survival analysis of appendiceal tumors in the United States: Primarily changes in appendiceal neuroendocrine tumors

BACKGROUND

Appendiceal tumors are considered to be a relatively rare tumor of the gastrointestinal tract and the prognosis is unclear. This study comprehensively investigated trends in the epidemiology and survival of appendiceal tumors in the United States over the past approximately 20 years.

METHODS

Patients with pathologically confirmed appendiceal tumors from 2000 to 2017 were selected from the Surveillance, Epidemiology and End Results (SEER) database. Age-adjusted incidence rates were calculated by SEER*Stat 8.4.0. The Kaplan-Meier method was used to analyze survival and prognostic factors were investigated by a multivariate Cox proportional risk model.

RESULTS

Ultimately, 13,546 patients with appendiceal tumors between 2000 and 2017 were included. The annual incidence of colonic adenocarcinoma and mucinous adenocarcinoma remained relatively stable. Interestingly, the annual incidence of appendiceal neuroendocrine tumors (aNETs) increased significantly, from 0.03 to 0.90 per 100,000 person-years, with the most dramatic increase in the number of patients with localized disease. Patients with aNETs showed a significant improvement in survival between 2009-2017, compared to the period 2000-2008. Moreover, this improvement in survival over time was seen at all stages (localized, regional, distant) of aNETs. However, this improved survival over time was not seen in colonic and mucinous adenocarcinoma.

CONCLUSIONS

The incidence of appendiceal neoplasms has increased significantly over the past nearly two decades, which is mainly due to the increased incidence and significant migration to earlier stages in aNETs. We must note that despite the increased incidence of aNETs, survival rates have improved at different disease stages.

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.

Cancer-specific survival in non-mucinous appendiceal adenocarcinomas after local resection versus right hemicolectomy: A Surveillance, Epidemiology, and End Results database study

BACKGROUND

Adenocarcinomas of the appendix are rare cancers for which no National Comprehensive Cancer Network guidelines exist, and for patients who undergo resection with curative intent, there is a paucity of data on prognostic factors affecting long-term cancer-specific survival. We aimed to compare the cancer-specific survival outcomes in adult patients with appendiceal non-mucinous adenocarcinoma undergoing either local resection versus right hemicolectomy.

METHODS

This was a retrospective study from the National Cancer Institute Surveillance, Epidemiology, and End Results of patients who underwent curative resection over a 15-year period (2004-2019) for primary appendiceal adenocarcinoma. Out of 16,699 patients, 14,945 were excluded (exclusion criteria were non-adenocarcinoma histological types and patients with regional or distant metastasis as per National Cancer Institute Surveillance, Epidemiology, and End Results stage). Effects of factors (age, race, tumor biology [mucinous versus non-mucinous tumors], the extent of resection of the primary lesion, and lymph nodes) on cancer-specific long-term survival were studied. Survival analysis was performed using the Kaplan-Meier method. Survival outcomes were reported as mean survival (months).

RESULTS

Of 1,754 patients, 827 (47.1%) were women, and 927 (52.1%) were men. The mean age in years (± standard deviation) was 62.43 ± 14.3. The racial distribution was as follows: Black 237 (13.5%), White 1,398 (79.7%), and Other 119 (6.8%). A total of 771 (44.6%) underwent local resection (appendectomy or segmental resection of colon without lymph node resection), and 983 (55.4%) underwent hemicolectomy with lymph node resection. Favorable survival prognosticators were age <50 years, White race, and well-differentiated histology. Patients with mucinous tumors experienced better survival. Patients who underwent right hemicolectomy with lymph node resection experienced better survival compared with those who had an appendectomy or segmental colonic resection for non-mucinous tumors rather than mucinous tumors.

CONCLUSION

We report novel demographic, tumor-related, and operative prognostic factors impacting long-term cancer-specific survival in patients who undergo resection for appendiceal adenocarcinoma. The extent of resection of the primary lesion with draining lymph nodes determines long-term cancer-specific survival in non-mucinous appendiceal adenocarcinomas.

High Incidence of Appendiceal Neoplasms in the Elderly: A Critical Concern for Non-Surgical Treatment

OBJECTIVE

Appendiceal neoplasms (ANs) are rare tumors that are often discovered incidentally during histopathological examinations. The increasing incidence of ANs is a critical issue in the non-operative management of acute appendicitis. This study aimed to document the temporal trends over a 12-year period by analyzing the clinical presentation, imaging findings, and histopathological features of ANs.

SUBJECTS AND METHODS

Health records of patients who underwent appendectomy from 2011 to 2022 were examined. Demographic and clinical data, laboratory results, imaging findings, and histopathological features were documented. The characteristics of both ANs and non-neoplastic cases were evaluated.

RESULTS

A total of 22,304 cases were identified, of which 330 (1.5%) were diagnosed with ANs. The odds ratio for ANs increased with age, with the highest odds ratio observed in patients aged 70 or older. Receiver Operating Characteristic analysis showed that age and appendiceal diameter were significant predictors of ANs. An optimal age cut-off point of 28.5 years was determined, yielding a sensitivity of 72% and a specificity of 64%. For appendiceal diameter, the optimal cut-off was found to be 9.5 mm, exhibiting a sensitivity of 77% and a specificity of 56%.

CONCLUSION

Although the incidence of ANs remains relatively low, a steady increase has been observed over the past decade. The increasing rate of ANs raises concerns regarding non-surgical management options. The results of this study highlight the importance of considering ANs as a potential diagnosis in older patients and in patients with an appendix diameter greater than 9.5 mm. These findings may have implications for treatment and management.

The Promise of Epigenetics Research in the Treatment of Appendiceal Neoplasms

Appendiceal cancers (AC) are a rare and heterogeneous group of malignancies. Historically, appendiceal neoplasms have been grouped with colorectal cancers (CRC), and treatment strategies have been modeled after CRC management guidelines due to their structural similarities and anatomical proximity. However, the two have marked differences in biological behavior and treatment response, and evidence suggests significant discrepancies in their respective genetic profiles. In addition, while the WHO classification for appendiceal cancers is currently based on traditional histopathological criteria, studies have demonstrated that histomorphology does not correlate with survival or treatment response in AC. Due to their rarity, appendiceal cancers have not been studied as extensively as other gastrointestinal cancers. However, their incidence has been increasing steadily over the past decade, making it crucial to identify new and more effective strategies for detection and treatment. Recent efforts to map and understand the molecular landscape of appendiceal cancers have unearthed a wealth of information that has made it evident that appendiceal cancers possess a unique molecular profile, distinct from other gastrointestinal cancers. This review focuses on the epigenetic landscape of epithelial appendiceal cancers and aims to provide a comprehensive overview of the current state of knowledge of epigenetic changes across different appendiceal cancer subtypes, highlighting the challenges as well as the promise of employing epigenetics in the quest for the detection of biomarkers, therapeutic targets, surveillance markers, and predictors of treatment response and survival in epithelial appendiceal neoplasms.

The Impact of Germline Alterations in Appendiceal Adenocarcinoma

PURPOSE

More than 10% of assessed patients with appendiceal adenocarcinoma have a pathogenic (P) or likely pathogenic (LP) germline variant, including genes implicated in heritable gastrointestinal cancer syndromes, such as Lynch syndrome. We defined the clinical and molecular impact of heritable alterations in appendiceal adenocarcinoma to evaluate the need for dedicated appendiceal screening and prevention strategies in patients with LP/P germline variants.

EXPERIMENTAL DESIGN

We performed an integrated germline and somatic molecular analysis for patients with confirmed appendiceal adenocarcinoma. Patients underwent paired tumor-normal sequencing for up to 90 hereditary cancer risk genes and 505 genes for somatic mutation profiling. We defined the cooccurrence of LP/P germline variants and second-hit pathogenic somatic alterations. The associations between germline variants and patient clinicopathologic features were also evaluated.

RESULTS

Twenty-five of 237 patients (10.5%) carried pathogenic or likely pathogenic germline variants in cancer susceptibility genes. Clinicopathologic characteristics and appendiceal adenocarcinoma-specific survival were similar in patients with or without germline variants. Most (92%, N = 23/25) patients with germline variants demonstrated no second-hit somatic alterations, including loss of heterozygosity. Two patients with a germline APC I1307K low-penetrance founder variant exhibited secondary somatic pathogenic alterations in APC. However, only one patient tumor exhibited APC-mediated WNT signaling dysregulation: a plausible consequence of multiple somatic APC mutations with no germline variant contribution. Four patients had germline variants in PMS2 or MSH2 associated with Lynch syndrome, yet their cancers were microsatellite-stable.

CONCLUSIONS

Germline variants are likely incidental without a contributory driver role in appendiceal adenocarcinoma. Appendiceal adenocarcinoma screening in patients with germline variants is not clearly merited.

Survival benefits with EPIC in addition to HIPEC for low grade appendiceal neoplasms with pseudomyxoma peritonei: a propensity score matched study

Objectives

Appendiceal cancer is a rare malignancy, occurring in roughly 1.2 per 100,000 per year. Low grade appendiceal neoplasams (LAMN) in particular can lead to pseudomyxoma peritonei (PMP), and respond poorly to systemic chemotherapy. Standard treatment includes cytoreduction surgery (CRS) with addition of heated intraoperative peritoneal chemotherapy (HIPEC). Several centres include early postoperative intraperitoneal chemotherapy (EPIC) however; the literature is mixed on the benefits. We aim to examine the benefits of additional EPIC through a propensity-matched analysis.

Methods

Patients with LAMN with PMP who underwent cytoreductive surgery at St George hospital between 1996 and 2020 were included in this retrospective analysis. Propensity score matching was performed with the following used to identify matched controls; sex, age, American Society of Anesthesiologists (ASA) grade, peritoneal cancer index (PCI) and morbidity grade. Outcomes measured included length of stay and survival.

Results

A total of 224 patients were identified of which 52 received HIPEC alone. Propensity matching was performed to identify 52 matched patients who received HIPEC + EPIC. Those receiving HIPEC + EPIC were younger at 54.3 vs. 58.4 years (p=0.044). There was a median survival benefit of 34.3 months for HIPEC + EPIC (127.3 vs. 93.0 months, p=0.02). Median length of stay was higher in those who received EPIC (25.0 vs. 23.5 days, p=0.028).

Conclusions

In LAMN with PMP, the addition of EPIC to HIPEC with CRS improves overall survival in propensity score matched cases but results in prolonged hospitalisation. The use of EPIC should still be considered in selected patients.

Impact of neoadjuvant systemic chemotherapy followed by cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for appendiceal adenocarcinoma

AIM

Peritoneal dissemination of infiltrative appendiceal tumors is a rare and poorly understood phenomenon. Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) is a well-recognized treatment option for selected patients. Neoadjuvant systemic chemotherapy (NAC) has been shown to be associated with improved overall survival (OS) in colorectal peritoneal metastases but little is known of the impact of this from an appendiceal adenocarcinoma perspective.

METHOD

A prospective database of 294 patients with advanced appendiceal primary tumors undergoing CRS ± HIPEC between June 2009 and December 2020 was reviewed. Baseline characteristics and long-term outcomes were compared between patients with adenocarcinoma who received neoadjuvant chemotherapy or upfront surgery.

RESULTS

Eighty-six (29%) patients were histologically diagnosed with an appendiceal cancer. These included intestinal-type adenocarcinoma (11.6%), mucinous adenocarcinoma (43%), and goblet cell adenocarcinoma (GCA) or signet ring cell adenocarcinoma (SRCA) (45.4%). Twenty-five (29%) of these underwent NAC, of which eight (32%) exhibited some degree of radiological response. There was no statistical difference in OS at 3 years between the NAC and upfront surgery groups (47.3% vs. 75.8%, p = 0.372). Appendiceal histology subtypes, particularly GCA and SRCA (p = 0.039) and peritoneal carcinomatosis index >10 (p = 0.009), were factors independently associated with worse OS.

CONCLUSION

Administration of NAC did not appear to prolong OS in the operative management of disseminated appendiceal adenocarcinomas. GCA and SRCA subtypes display a more aggressive biological phenotype.

Appendiceal adenocarcinoma is associated with better prognosis than cecal adenocarcinoma: a population-based comparative survival study

OBJECTIVE

Although appendiceal cancer remains a rare gastrointestinal malignancy compared with colorectal cancer, incidence rates of appendiceal cancer have increased in the last two decades. Appendiceal and cecal adenocarcinomas have distinct genomic profiles, but chemotherapy protocols for these malignancies are the same and survival outcomes between them have not been compared extensively. To this end, we conducted a comparative survival analysis of appendiceal and cecal adenocarcinomas.

DESIGN

Using the Surveillance, Epidemiology and End Results (SEER) database, we identified individuals ≥30 years of age with appendiceal or cecal adenocarcinoma from 1975 to 2016. Demographic, clinical and county-level socioeconomic data were extracted using SEER*Stat software. Survival was compared by Mantel-Haenszel log-rank test, and survival curves were generated using the Kaplan-Meier method. Relative HRs for death in the 5-year period following diagnosis were calculated using multivariable Cox regression analysis, adjusted for all other covariates. The significance level was set at p<0.05 for two-tailed tests. Data were analysed using SAS V.9.4 and R software.

RESULTS

We identified 6491 patients with appendiceal adenocarcinoma and 99 387 patients with cecal adenocarcinoma. Multivariable Cox regression analysis demonstrated significantly higher cancer-specific and overall survival in appendiceal adenocarcinoma compared with cecal adenocarcinoma. Male sex, older age, earlier year of diagnosis, black race, single marital status, non-Hispanic ethnicity, and non-mucinous histology were associated with increased mortality rates. In addition, counties with lower percentage of individuals below the poverty line and higher colorectal cancer screening rates had better survival.

CONCLUSION

This is the first study to show greater survival in appendiceal adenocarcinoma compared with cecal adenocarcinoma. We also highlighted novel associations of county-level socioeconomic factors with increased mortality in appendiceal adenocarcinoma. Future efforts to develop targeted molecular therapies and reduce socioeconomic barriers to diagnosis and treatment are warranted to improve survival.

The other colon cancer: a population-based cohort study of appendix tumour trends and prognosis

AIM

Appendiceal neoplasms are rare subtypes of colorectal tumours that mainly affect younger patients some 20 years earlier than other colon tumours. The aim of this study was to gain more insight into the histological subtypes of this rare disease and include cases previously excluded, such as mucinous neoplasia.

METHOD

The cohort study included 1097 patients from the Munich Cancer Registry (MCR) diagnosed between 1998 and 2020. Joinpoint analysis was used to determine trend in incidence. Baseline demographic comparisons and survival analyses using competing risk and univariate/multivariate methods were conducted according to tumour histology: adenocarcinoma (ADENO), neuroendocrine neoplasia (NEN), mixed adeno-neuroendocrine carcinoma (MANEC), and low- (LAMN) and high-grade mucinous neoplasia (HAMN).

RESULTS

Up to 2016 the number of cases increased significantly [annual per cent change (APC) = 6.86, p < 0.001] followed by a decline in the following years (APC = -14.82, p = 0.014; average APC = 2.5, p = 0.046). Comparison of all patients showed that NEN (48.4%) and mucinous neoplasms (11.6%) had a considerably better prognosis than ADENO (36.0%) and MANEC (3.0%, p < 0.0001). A multivariate analysis within the NEN and ADENO subgroups revealed that further histological classification was not prognostically relevant, while older age and regional tumour spread at diagnosis were associated with a poor prognosis. ADENO histology with high tumour grade and appendectomy only was also associated with poorer survival.

CONCLUSION

Appendiceal neoplasms are histologically heterogeneous; however, this diversity becomes less relevant compared with the marked difference from cancers of the remaining colon. The previously observed increase in cases appears to be abating; fewer cases of appendicitis and/or appendectomies or changes in histopathological assessment may be behind this trend.

Inherited Cancer Susceptibility Gene Sequence Variations Among Patients With Appendix Cancer

Importance

Germline sequence variations in APC, BMPR1A, CDH1, CHEK2, EPCAM, MLH1, MSH2, MSH6, MUTYH, PMS2, PTEN, SMAD4, STK11, and TP53 genes are associated with susceptibility to gastrointestinal cancers. As a rare cancer, the evaluation of appendiceal cancer (AC) predisposition has been limited.

Objective

To assess the prevalence and spectrum of inherited cancer susceptibility gene sequence variations in patients with AC and the utility of germline genetic testing for this population.

Design, Setting, and Participants

This cohort study included patients with AC who underwent germline genetic testing of 14 cancer susceptibility genes performed by a clinical testing laboratory between March 1, 2012, and December 31, 2016. Data were analyzed from March to August 2022. Clinical, individual, and family histories were obtained from clinician-completed test requisition forms. Multigene panel testing was performed by targeted custom capture and sequencing and chromosome rearrangement analysis.

Main Outcomes and Measures

The main outcomes were germline sequence variation prevalence and spectrum in patients with AC.

Results

Among the 131 patients with AC in the cohort (90 female [68.7%]), a total of 16 deleterious sequence variations were identified in 15 patients (11.5%). Similarly, when limited to the 74 patients with AC as the first and only primary tumor, a total of 8 patients (10.8%) had at least 1 deleterious sequence variation in a cancer susceptibility gene. Overall, 6 patients (4.6%) had a deleterious sequence variation observed in MUTYH (5 with monoallelic MUTYH and 1 with biallelic MUTYH). All 4 patients with Lynch syndrome (3.1%) had a sequence variation in the MLH1 gene, of whom 3 were aged 50 years or older at AC diagnosis. Five patients (3.8%) had deleterious sequence variations in other cancer predisposition genes (1 with APC [c.3920T>A, p.I1307K], 2 with CHEK2 [c.470T>C, p.I157T], 1 with SMAD4 [c.263 287dup, p.L98IFS*14], and 1 with TP53 [c.524G>A, p.R175H]).

Conclusions and Relevance

In this cohort study, 1 in every 10 patients with AC who underwent testing for hereditary cancer predisposition carried an inherited gene sequence variation associated with cancer susceptibility. Given the high frequency and broad spectrum of germline gene sequence variations, these data suggest that genetic evaluation might be warranted for all patients diagnosed with this rare malignant tumor. A systemic sequencing effort for all patients with AC may also identify cancer vulnerabilities to exploit for therapeutic development in a cancer type for which clinical trials are limited.

Development of an unsupervised cycle contrastive unpaired translation network for MRI-to-CT synthesis

Purpose

The purpose of this work is to develop and evaluate a novel cycle‐contrastive unpaired translation network (cycleCUT) for synthetic computed tomography (sCT) generation from T1‐weighted magnetic resonance images (MRI).

Methods

The cycleCUT proposed in this work integrated the contrastive learning module from contrastive unpaired translation network (CUT) into the cycle‐consistent generative adversarial network (cycleGAN) framework to effectively achieve unsupervised CT synthesis from MRI. The diagnostic MRI and radiotherapy planning CT images of 24 brain cancer patients were obtained and reshuffled to train the network. For comparison, the traditional cycleGAN and CUT were also implemented. The sCT images were then imported into a treatment planning system to verify their feasibility for radiotherapy planning. The mean absolute error (MAE), peak signal‐to‐noise ratio (PSNR), and structural similarity index (SSIM) between the sCT and the corresponding real CT images were calculated. Gamma analysis between sCT‐ and CT‐based dose distributions was also conducted.

Results

Quantitative evaluation of an independent test set of six patients showed that the average MAE was 69.62 ± 5.68 Hounsfield Units (HU) for the proposed cycleCUT, significantly (p‐value < 0.05) lower than that for cycleGAN (77.02 ± 6.00 HU) and CUT (78.05 ± 8.29). The average PSNR was 28.73 ± 0.46 decibels (dB) for cycleCUT, significantly larger than that for cycleGAN (27.96 ± 0.49 dB) and CUT (27.95 ± 0.69 dB). The average SSIM for cycleCUT (0.918 ± 0.012) was also significantly higher than that for cycleGAN (0.906 ± 0.012) and CUT (0.903 ± 0.015). Regarding gamma analysis, cycleCUT achieved the highest passing rate (97.95 ± 1.24% at the 2%/2 mm criteria and 10% dose threshold) but was not significantly different from the others.

Conclusion

The proposed cycleCUT could be effectively trained using unaligned image data, and could generate better sCT images than cycleGAN and CUT in terms of HU number accuracy and fine structural details.

Demographic trends in the incidence of malignant appendiceal tumours in England between 1995 and 2016: Population-based analysis

AIMS

Recent data suggest that the incidence of malignant appendiceal tumours is increasing. This study aimed to determine temporal trends in the incidence of malignant appendiceal tumours within England and a possible influence by demographic factors.

METHODS

All incident cases of appendiceal tumours in patients aged 20 years and above were identified from the National Cancer Registration and Analysis Service database between 1995 and 2016 using ICD-9/10 codes. Cancers were categorized according to histology. Joinpoint regression analysis was used to investigate changes in age-standardized incidence rates by age, sex, histological subtype and index of multiple deprivation quintiles, based on socioeconomic domains (income, employment, education, health, crime, barriers to housing and services and living environment). Average annual per cent changes (AAPCs) were estimated by performing Monte-Carlo permutation analysis.

RESULTS

A total of 7333 tumours were diagnosed and 7056 patients were analysed, comprising 3850 (54.6 per cent) neuroendocrine tumours (NETs), 1892 (26.8 per cent) mucinous adenocarcinomas and 1314 (18.6 per cent) adenocarcinoma (not otherwise specified). The overall incidence of appendiceal tumours increased from 0.3 per 100 000 to 1.6 per 100 000 over the study interval. Incidence rate increases of comparable magnitude were observed across all age groups, but the AAPC was highest among patients aged 20-29 years (15.6 per cent, 95 per cent c.i 12.7-18.6 per cent) and 30-39 years (14.2 per cent, 12.2-16.2 per cent) and lowest among those aged 70-79 years (6.8 per cent, 5.7-8.0 per cent). Similar incidence rate increases were reported across all socioeconomic deprivation quintiles and in both sexes. Analysis by grade of NET showed that grade 1 tumours accounted for 63 per cent between 2010 and 2013, compared with 2 per cent between 2000 and 2003.

CONCLUSIONS

The incidence rate of malignant appendiceal tumours has increased significantly since 1995 and is mainly attributed to an increase in NETs. The increased diagnosis of low-grade NETs may in part be due to changes in pathological classification systems.

Appendiceal Cancer in the National Cancer Database: Increasing Frequency, Decreasing Age, and Shifting Histology

BACKGROUND

Nonoperative management of acute appendicitis is increasingly common. However, small studies have demonstrated high rates of appendiceal cancer in interval appendectomy specimens. Therefore, we sought to identify national trends in appendiceal cancer incidence and histology.

STUDY DESIGN

The National Cancer Database was queried for patients 18 years or older, diagnosed with a right-sided colon cancer (including appendiceal) from 2004 to 2017 who had undergone surgery. Outcomes included trends in appendiceal cancer compared with right-sided colon cancers and trends in appendiceal cancer histology. Logistic regression was used to assess trends over time while adjusting for patient age, insurance, income, area of residence, and comorbidity. Predicted probabilities of the outcomes were derived from the logistic regression models.

RESULTS

Of 387,867 patients with right-sided colon cancer, 19,570 had appendiceal cancer and of those 5,628 had a carcinoid tumor. Odds of appendiceal cancer, relative to other right-sided colon cancers, increased from 2004 to 2017 (odds ratio [OR] 2.56, 95% CI 2.35-2.79). The increase occurred in all age groups; however, it was more markedly increased in patients 40-49 years old (2004: 10%, 95% CI 9-12 to 2017: 18%, 95% CI 16-20; pairwise comparisons p < 0.001). Odds of appendiceal carcinoid, relative to other appendiceal histologies, increased from 2004 to 2017 (OR 1.70, 95% CI 1.40-2.07) with the greatest increase in probability of a carcinoid in patients younger than 40 years old (2004: 24%, 95% CI 15-34 to 2017: 45%, 95% CI 37-53; pairwise comparisons p < 0.001).

CONCLUSION

Appendiceal cancer has increased over time, and the increase appears to be driven by a rise in carcinoids, most prevalent in patients 49 years of age or younger. When nonoperative management of acute appendicitis is undertaken, close follow-up may be appropriate given these findings.

Training and Management Status of Wound, Ostomy, and Continence (WOC) Nurses: A Cross-Sectional Survey From China

Objective: To investigate the current situation with regard to training and management of wound, ostomy, and continence (WOC) nurses in China.

Methods: A self-designed questionnaire was used to investigate the training and management of WOC nurses.

Results: A total of 218 WOC nurses received cross-sectional surveys. Out of these nurses, 57.30% graduated from the International Stoma Therapists School, 22.90% were full-time WOC nurses, only 24.80% had engaged in funded research, and 26.10% had an additional allowance. There is room for further improvement in the field of education, scientific research, and self-development.

Conclusion: WOC work has developed rapidly in China, and there have been some achievements in personnel training, specialized nursing, teaching, and scientific research.

Incidentally found mucinous epithelial tumors of the appendix with or without pseudomyxoma peritonei: diagnostic and therapeutic algorithms based on current evidence

Mucinous appendiceal tumors with or without the pseudomyxoma peritonei (PMP) syndrome are rare, but often present as an incidental finding. The confusing histology and lack of large prospective trials result in a considerable diagnostic and therapeutic challenge in these patients. We propose treatment algorithms in patients with incidentally found mucinous epithelial appendiceal tumors, with or without PMP, based on the currently available evidence. The therapeutic approach should take into account the histology and grade of the primary appendix tumor, as well as those of the associated peritoneal disease.

Histologic and Racial/Ethnic Patterns of Appendiceal Cancer among Young Patients

BACKGROUND

Appendiceal cancer incidence among individuals age < 50 years (early-onset appendiceal cancer) is rising with unknown etiologies. Distinct clinicopathologic/demographic features of early-onset appendiceal cancer remain unexplored. We compared patterns of appendiceal cancer among individuals by age of disease-onset.

METHODS

Using the NIH/NCI's Surveillance, Epidemiology, and End Results program data, we identified individuals age 20+ years diagnosed with appendiceal cancer from 2007 to 2016. Cochran-Armitage trend tests and multinomial logistic regression models were used to examine age-related differences in clinicopathologic/demographic features of appendiceal cancer.

RESULTS

We identified 8,851 patients with appendiceal cancer during the 10-year study period. Histologic subtype, tumor grade, stage, sex and race/ethnicity all significantly differed by age of appendiceal cancer diagnosis. After adjustment for race/ethnicity, sex, stage, insurance status, and tumor grade, young patients were 82% more likely to be Hispanic [OR, 1.82; 95% confidence interval (CI), 1.48-2.25; P < 0.001] and 4-fold more likely to be American Indian or Alaska Native (OR, 4.02; 95% CI, 1.77-9.16; P = 0.0009) compared with late-onset cases. Patients with early-onset appendiceal cancer were also 2- to 3.5-fold more likely to be diagnosed with neuroendocrine tumors of the appendix (goblet cell carcinoid: OR, 1.96; 95% CI, 1.59-2.41; P < 0.0001; carcinoid: OR, 3.52; 95% CI, 2.80-4.42; P < 0.0001) compared with patients with late-onset appendiceal cancer. Among patients with neuroendocrine tumors, early-onset cases were also 45% to 61% less likely to present with high-grade (III-IV) tumors.

CONCLUSIONS

Approximately one in every three patients with appendiceal cancer is diagnosed before age 50 years in the United States. Appendiceal cancer in young patients is classified by distinct histologic and demographic features.

IMPACT

Early-onset appendiceal cancer determinants can inform discovery of risk factors and molecular biomarkers of appendiceal cancer in young patients, with implications for appendiceal cancer prevention, detection, and treatment.

Rising incidence of appendiceal neoplasms over time: Does pathological handling of appendectomy specimens play a role?

BACKGROUND

Appendectomy is the most common emergent surgical procedure. Primary appendiceal neoplasms are rare entities that are usually detected incidentally in less than 2% of all appendectomies. The increase in the incidence rates of appendiceal neoplasms over time raises the question whether there is an actual change in the disease occurrence or is it a matter of increased recognition and reporting of what would have been previously missed and undiagnosed.

OBJECTIVES

In our study, we aimed to review the archived tissue specimens of patients who were diagnosed with appendiceal neoplasms during the past decade at our institution and compare our clinical experience with published data to identify possible reasons that contribute to the increase in incidence rates of such neoplasms over the past few years.

METHODS

Using a pathological database of surgical specimens from patients who underwent appendectomies between January 01, 2010 and September 30, 2020 at a large academic medical center, a single-center retrospective cohort analysis was performed, and medical charts of patients were reviewed.

RESULTS

Of the total 1568 patients included, 102 (6.5%) had appendiceal neoplasms divided between primary (79.4%) and secondary/metastatic (20.6%) neoplasms. Annual incidence of appendiceal neoplasms over the past 10 years in our institution demonstrated an increasing trend from 5.6% in 2010 to 12.7% in 2020, which we hypothesize might be attributed to submitting more representative sections of the appendix for pathological examination than we had previously. Our results also showed that 2.8% of patients initially presenting with a typical clinical picture of acute appendicitis had appendiceal neoplasms as a truly incidental finding, while 20.3% of patients who underwent elective appendectomies for a suspicious appendiceal mass were found to be neoplastic. Interestingly, among the 80 cases of epithelial neoplasms, more non-carcinoid neoplasms were detected than carcinoid tumors.

CONCLUSION

Based on our results and what has been published recently, we confirm an additional increase in incidental appendiceal neoplasms found in appendectomies performed for a clinical picture of acute appendicitis, which may be related to more thorough specimen assessment. Whether this is clinically impactful remains to be determined. However, these data support a modification in the way appendectomy specimens are handled in pathology labs post-operatively.

Update on gastroenteropancreatic neuroendocrine tumors

The incidence gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) has dramatically risen over the last three decades, probably due to the increased detection of asymptomatic lesions. The diagnostic work-up for patients with suspected GEP-NENs is based on conventional imaging, endoscopy, pathology, and functional imaging, including ⁶⁸Gallium-DOTATATE PET and ¹⁸F-FDG PET. The choice of the best treatment strategy should be based on the evaluation of tumor-related features and patient's characteristics. A conservative management, consisting of active surveillance or endoscopic resection, has been advocated for patients with small, incidentally discovered, nonfunctioning tumors without features of aggressiveness. On the other hand, surgery with lymphadenectomy, also with a minimally invasive approach, represents the gold standard for the curative treatment of localized disease. Moreover, surgical resection plays an important role also in the context of a multimodal treatment strategy for patients with advanced GEP-NENs. Finally, a wide range of medical therapies, comprising somatostatin analogues, peptide receptor radionuclide therapy, target therapies and several chemotherapy regimens, can be offered to patients with advanced GEP-NENs not amenable of surgical resection, according to the biological and molecular features of their disease.

Spectrum of Somatic Cancer Gene Variations Among Adults With Appendiceal Cancer by Age at Disease Onset

Importance

The incidence of appendiceal cancer (AC) is rising, particularly among individuals younger than 50 years (early-onset AC), with unexplained etiologies. The unique spectrum of somatic cancer gene variations among patients with early-onset AC is largely undetermined.

Objective

To characterize the frequency of somatic variations and genomic patterns among patients with early-onset (age <50 years) vs late-onset (age ≥50 years) AC.

Design, Setting, and Participants

This cohort study included individuals aged 18 years and older diagnosed with pathologically verified AC. Cases with clinical-grade targeted sequencing data from January 1, 2011, to December 31, 2019, were identified from the international clinicogenomic data-sharing consortium American Association for Cancer Research Project Genomics Evidence Neoplasia Information Exchange (GENIE). Data analysis was conducted from May to September 2020.

Exposures

Age at disease onset.

Main Outcomes and Measures

Somatic variation prevalence and spectrum in AC patients was determined. Variation comparisons between early-onset and late-onset AC were evaluated using multivariable logistic regression with adjustment for sex, race/ethnicity, histological subtype, sequencing center, and sample type.

Results

In total 385 individuals (mean [SD] age at diagnosis, 56.0 [12.4] years; 187 [48.6%] men; 306 [79.5%] non-Hispanic White individuals) with AC were included in this study, and 109 patients (28.3%) were diagnosed with early-onset AC. Race/ethnicity differed by age at disease onset; non-Hispanic Black individuals accounted for a larger proportion of early-onset vs late-onset cases (9 of 109 [8.3%] vs 11 of 276 [4.0%]; P = 0.04). Compared with patients aged 50 years or older at diagnosis, patients with early-onset AC had significantly higher odds of presenting with nonsilent variations in PIK3CA, SMAD3, and TSC2 (PIK3CA: odds ratio [OR], 4.58; 95% CI, 1.72-12.21; P = .002; SMAD3: OR, 7.37; 95% CI, 1.24-43.87; P = .03; TSC2: OR, 12.43; 95% CI, 1.03-149.59; P = .047). In contrast, patients with early-onset AC had a 60% decreased odds of presenting with GNAS nonsilent variations compared with patients with late-onset AC (OR, 0.40; 95% CI, 0.21-0.76, P = .006). By histological subtype, young patients with mucinous adenocarcinomas of the appendix had 65% decreased odds of variations in GNAS compared with late-onset cases in adjusted models (OR, 0.35; 95% CI, 0.15-0.79; P = .01). Similarly, patients with early-onset nonmucinous appendiceal adenocarcinomas had 72% decreased odds of presenting with GNAS variations vs late-onset cases, although these findings did not reach significance (OR, 0.28; 95% CI, 0.07-1.14; P = .08). GNAS and TP53 variations were mutually exclusive in ACs among early-onset and late-onset cases (P < .05).

Conclusions and Relevance

In the study, AC diagnosed among younger individuals harbored a distinct genomic landscape compared with AC diagnosed among older individuals. Development of therapeutic modalities that target these unique molecular features may yield clinical implications specifically for younger patients.

A 30-Year Long-Term Experience in Appendix Neuroendocrine Neoplasms-Granting a Positive Outcome

Neuroendocrine neoplasms (NENs) are the most common tumor of the appendix and have an excellent prognosis. Appendiceal tumors diagnosed between 1989 and 2019 were reviewed, and clinical data were collected from patient files. Part of the series was immuno-profiled for markers related to cell cycle proliferation and/or senescence-type, apoptotic, and metastatic potential. Appendix NENs were detected in 74 patients, with 0.47% of incidence per appendectomy. The median age of the patients was 21.5 years, with two age peaks of incidence at 17.0 and 55.2 years. The median tumors size was 5.8 mm, and most were smaller than 10 mm. Lymphovascular and perineural invasion, as well as necrosis, was associated with larger tumor size. G1 tumors composed 96.0% of the cohort. The presence of moderate/strong p16 and the absent/low Bcl-2 expression was frequently observed and associated with a smaller size. This study represents one of the largest cohorts and with a long follow-up. For tumors smaller than 10 mm appendicectomy was sufficient as a curative procedure, as revealed by the good outcome. This series presented a 100% disease-free survival. The indolent phenotype of appendix NENs is supported by the expression of markers that point towards a strong inhibition of cell replication and growth inhibition.