Incidence and Survival of Appendiceal Mucinous Neoplasms: A SEER Analysis

Clinical Significance of Circulating Tumor Cells in Epithelial Appendiceal Neoplasms with Peritoneal Metastases

Appendiceal tumors are uncommon and, at times, discovered incidentally during histological examination. The histopathological classification of the disease is complex and has generated some controversy. The analysis of circulating tumor cells can be used for the early detection of metastatic potential. The aim of the present study was to examine the prognostic value of circulating tumor cells in patients with appendiceal tumors and peritoneal metastases. To our knowledge, this is the first study to examine CTCs in appendiceal tumors. We performed a prospective cohort study of consecutive patients treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy between 2015 and 2019 at a HIPEC referral center. In total, 31 patients were included in the analysis, and circulating tumor cells were detected in 15 patients (48%). CTC positivity was not associated with overall or recurrence-free survival, nor was it correlated with PCI score or histopathological grading. Surprisingly, however, CTCs were found in almost half the patients. The presence or quantities of these cells did not, on their own, predict systemic metastatic potential during the observed time, and they did not appear to significantly correlate with the oncological outcomes recorded.

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.

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.

Epidemiologic characteristics and risk factors associated with overall survival for patients with mucinous colorectal cancer: A population-based study

BACKGROUND

Mucinous adenocarcinoma (MC) has attracted much attention as a distinct histologic subtype of colorectal cancer in recent years. However, data about its epidemiologic and prognostic characteristics are limited. Therefore, patient data extracted from the National Cancer Institute's Surveillance, Epidemiology, and End Results Program were collected to analyze the epidemiologic and clinicopathological characteristics of MC.

AIM

To determine the epidemiologic and clinicopathological characteristics of MC.

METHODS

The incidence trend of MC was calculated through the Joinpoint Regression Program. Cox regression analyses were performed to identify prognostic factors associated with overall survival (OS). A nomogram was established to predict the survival probability of individual patients with MC.

RESULTS

We found that rates of MC decreased from 4.50/100000 in 2000 to 1.54/100000 in 2018. Rates of MCs in patients aged ≤ 50 years decreased 2.27%/year during 2000-2018. The incidence of appendiceal MCs increased from 0.14/100000 in 2000 to 0.24/100000 in 2018, while the incidence in other anatomic subsites continued to decrease. On multivariable Cox analyses, age, race, tumor site, T stage, N stage, M stage, surgery, and chemotherapy were associated with OS. A nomogram was developed based on these factors, and the area under the curve for 1-year, 3-year, and 5-year OS in the training cohort was 0.778, 0.778, and 0.768, respectively.

CONCLUSION

Our results demonstrated that MC incidence decreased in almost all anatomic subgroups except for the appendix. A nomogram predicting the survival probability of patients with MCs showed good performance.

Incidence and outcomes of delayed presentation and surgery in peritoneal surface malignancies

Background

Peritoneal surface malignancies (PSM) present insidiously and often pose diagnostic challenges. There is a paucity of literature quantifying the frequency and extent of therapeutic delays in PSM and its impact on oncological outcomes.

Methods

A review of a prospectively maintained registry of PSM patients undergoing Cytoreductive Surgery and Hyperthermic Intra-peritoneal Chemotherapy (CRS-HIPEC) was conducted. Causes for treatment delays were identified. We evaluate the impact of delayed presentation and treatment delays on oncological outcomes using Cox proportional hazards models.

Results

319 patients underwent CRS-HIPEC over a 6-years duration. 58 patients were eventually included in this study. Mean duration between symptom onset and CRS-HIPEC was 186.0 ± 37.1 days (range 18-1494 days) and mean duration of between patient-reported symptom onset and initial presentation was 56.7 ± 16.8 days. Delayed presentation (> 60 days between symptom onset and presentation) was seen in 20.7% (n=12) of patients and 50.0% (n=29) experienced a significant treatment delay of > 90 days between 1^st presentation and CRS-HIPEC. Common causes for treatment delays were healthcare provider-related i.e. delayed or inappropriate referrals (43.1%) and delayed presentation to care (31.0%). Delayed presentation was a significantly associated with poorer disease free survival (DFS) (HR 4.67, 95% CI 1.11-19.69, p=0.036).

Conclusion

Delayed presentation and treatment delays are common and may have an impact on oncological outcomes. There is an urgent need to improve patient education and streamline healthcare delivery processes in the management of PSM.

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.

Clinicopathologic parameters and outcomes of mucinous neoplasms confined to the appendix: a benign entity with excellent prognosis

Appendiceal mucinous neoplasms (AMNs), characterized by expansile or "pushing" growth of neoplastic epithelium through the appendix wall, are sometimes accompanied by peritoneal involvement, the extent and grade of which largely determine clinical presentation and long-term outcomes. However, the prognosis of tumors entirely confined to the appendix is still debated and confusion remains regarding their biologic behavior and, consequently, their clinical management and even diagnostic nomenclature. We evaluated AMNs limited to the appendix from 337 patients (median age: 58 years, interquartile range (IQR): 47-67), 194 (57.6%) of whom were women and 143 (42.4%) men. The most common clinical indication for surgery was mass or mucocele, in 163 (48.4%) cases. Most cases (N = 322, 95.5%) comprised low-grade epithelium, but there were also 15 (4.5%) cases with high-grade dysplasia. Lymph nodes had been harvested in 102 (30.3%) cases with a median 6.5 lymph nodes (IQR: 2-14) per specimen for a total of 910 lymph nodes examined, all of which were negative for metastatic disease. Histologic slide review in 279 cases revealed 77 (27.6%) tumors extending to the mucosa, 101 (36.2%) to submucosa, 33 (11.8%) to muscularis propria, and 68 (24.4%) to subserosal tissues. In multivariate analysis, deeper tumor extension was associated with older age (p = 0.032; odds ratio (OR): 1.02, 95% confidence intervals (CI): 1.00-1.03), indication of mass/mucocele (p < 0.001; OR: 2.09, CI: 1.41-3.11), and wider appendiceal diameter, grossly (p < 0.001; OR: 1.61, CI: 1.28-2.02). Importantly, among 194 cases with at least 6 months of follow-up (median: 56.1 months, IQR: 24.4-98.5), including 9 high-grade, there was no disease recurrence/progression, peritoneal involvement (pseudomyxoma peritonei), or disease-specific mortality. These data reinforce the conclusion that AMNs confined to the appendix are characterized by benign biologic behavior and excellent clinical prognosis and accordingly suggest that revisions to their nomenclature and staging would be appropriate, including reverting to the diagnostic term mucinous adenoma in order to accurately describe a subset of them.

Misdiagnosed appendiceal mucinous neoplasms and primary ovarian mucinous tumors present with different pre- and intraoperative characteristics

Objective

To identify the differences between the pre- and intraoperative characteristics in misdiagnosed appendiceal mucinous neoplasms (AMNs) and those in primary ovarian mucinous tumors (POMTs) and to establish an effective model for differentiating AMNs from pelvic mucinous tumors.

Methods

This study enrolled 70 AMN patients who were misdiagnosed with ovarian tumors and 140 POMT patients who were treated from November 1998 to April 2021 at Peking Union Medical College Hospital. The clinical features and operative findings of the two groups of patients were collected and compared.

Results

There were significant differences in age and menopausal status, but no difference in the patients’ clinical manifestations between the two groups. The preoperative serum CA125 and CA199 levels were not different between the two groups. The CEA level (31.04 ± 42.7 vs. 7.11 ± 24.2 ng/ml) was higher in the misdiagnosed AMN group (P < 0.001). The AMNs were smaller than the POMTs that were measured preoperatively by ultrasonography (US) (P<0.05) and measured at surgery (P<0.05). Furthermore, the patients with AMNs more commonly had multinodularity and ascites noted on the preoperative US (P<0.001), on CT (P<0.001), and at surgery (P< 0.001). The two groups also differed in the presence of bilateral disease, in the appendiceal appearance and peritoneal dissemination. Subsequently, a prediction model was developed using multivariable logistic regression, which was evaluated through internal validation.

Conclusions

The suspicion of a nongenital organs originated tumor especially origing from appendiceal should be considered in a patient who is older, tumor size less than 12cm, multinodular, presence of mucinous ascites, and elevated serum CEA levels. Bilateral ovarian involvement, peritoneal dissemination, and an abnormal appendiceal appearance found during surgery were the typical features associated with AMNs.

Organoids From Mucinous Appendiceal Adenocarcinomas as High-Fidelity Models for Individual Therapy

Background

Mucinous appendiceal adenocarcinoma (MAA) is a rare, heterogeneous disease. Patients with unrespectable mucinous appendiceal adenocarcinoma presenting with peritoneal spread are treated by intraperitoneal chemotherapy, hyperthermic intraperitoneal chemotherapy, systemic chemotherapy, or targeted therapy. However, there are no guidelines for efficacious drugs against mucinous appendiceal adenocarcinoma. Therefore, relevant high-fidelity models should be investigated to identify effective drugs for individual therapy.

Methods

Surgical tumor specimens were obtained from a mucinous appendiceal adenocarcinoma patient. The tissue was digested and organoid culture was established. H&E and immunohistochemistry staining as well as DNA sequencing was performed on tissue and organoid. The pathological characteristics and gene mutations of the organoid were compared to those of the original tumor. Drug sensitivity tests were performed on organoid and the patient clinical responds to chemotherapy and targeted therapy was compared.

Results

Organoids were successfully established and stably passaged. Pathological characteristics of organoids including H&E staining and expression of protein markers (CK20, CDX-2, STAB2, CD7, PAX8) were consistent to those of the original tumor. Moreover, the organoids carried the same gene mutations as the primary tumor. Sensitivity of the organoids to chemotherapeutic drugs and tyrosine kinase inhibitors included: 5-FU (IC₅₀ 43.95 μM), Oxaliplatin (IC₅₀ 23.49 μM), SN38 (IC₅₀ 1.02 μM), Apatinib (IC₅₀ 0.10 μM), Dasatinib (IC₅₀ 2.27 μM), Docetaxel (IC₅₀ 5.26 μM), Regorafenib (IC₅₀ 18.90 μM), and Everolimus (IC₅₀ 9.20 μM). The sensitivities of organoid to these drugs were comparable to those of the patient's clinical responses.

Conclusion

The mucinous appendiceal adenocarcinoma organoid model which retained the characteristics of the primary tumor was successfully established. Combined organoid-based drug screening and high throughput sequencing provided a promising way for mucinous appendiceal adenocarcinoma treatment.

Inverted Appendix in a Patient With Weakness and Occult Bleeding

BACKGROUND

Appendiceal mucinous neoplasms (AMNs) are rare adenomatous primary tumors of the appendix. Although of low malignant potential, these neoplasms can cause serious potentially fatal complications such as bowel obstruction and pseudomyxoma peritonei, making prompt identification and removal of utmost importance. AMNs often present with nonspecific gastrointestinal symptoms or are asymptomatic and found incidentally.

CASE PRESENTATION

A patient aged 72 years presented with generalized weakness and appeared on imaging to have acute appendicitis complicated by rupture. On colonoscopy, the patient was found to have an inverted appendix that after appendectomy was revealed to harbor a perforated low-grade AMN.

CONCLUSIONS

Although AMNs are rare, physicians should still consider it when imaging suggests appendicitis. Having AMNs as part of the differential diagnosis is especially necessary in cases, such as this one, in which the patient has appendiceal inversion, is aged > 50 years, and has concurrent colorectal neoplasms.

The Utility of Preoperative Tumor Markers in Peritoneal Carcinomatosis from Primary Appendiceal Adenocarcinoma: an Analysis from the US HIPEC Collaborative

BACKGROUND

Prognostication based on preoperative clinical factors is lacking in patients undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). This study aims to determine the value of preoperative tumor markers as predictors of progression-free survival (PFS) and overall survival (OS) for patients with peritoneal carcinomatosis from a primary mucinous adenocarcinoma of the appendix (MACA).

METHODS

We queried the United States HIPEC Collaborative, a database of patients with peritoneal carcinomatosis treated with CRS/HIPEC at twelve institutions between 2000 and 2017, identifying 409 patients with MACA. Multivariate analysis was used to identify independent predictors of disease progression. Subgroup analysis was conducted to evaluate the impact of tumor grade on the predictive value of tumor markers.

RESULTS

CA19-9 [HR 2.44, CI 1.2-3.4] emerged as an independent predictor of PFS while CEA [HR 4.98, CI 1.06-23.46] was independently predictive of OS (p <0.01). Tumor differentiation was the most potent predictor of both PFS (poorly differentiated vs well, [HR 4.5 CI 2.01-9.94]) and OS ([poorly differentiated vs well-differentiated: [HR 13.5, CI 3.16-57.78]), p <0.05. Among patients with combined CA19-9 elevation and poorly differentiated histology, 86% recurred within a year of CRS/HIPEC (p < 0.01). Similarly, the coexistence of CEA elevation and unfavorable histology led to the lowest survival rate at two years [36%, p < 0.01]. CA-125 was not predictive of PFS or OS.

CONCLUSION

Elevated preoperative CA19-9 portends worse PFS, while elevated CEA predicts worse OS after CRS/HIPEC in patients with MACA. This study provides additional evidence that CA19-9 and CEA levels should be collected during standard preoperative bloodwork, while CA-125 can likely be omitted. Tumor differentiation, when added to preoperative tumor marker levels, provides powerful prognostic information. Prospective studies are required to confirm this association.

Enterocutaneous fistula resulting from the drainage of a contained appendiceal perforation secondary to a partially obstructing low-grade appendiceal mucinous neoplasm

We report a case of an enterocutaneous fistula resulting from drainage of a contained appendiceal perforation secondary to an obstructing appendiceal mucinous neoplasm. A 66-year-old otherwise healthy female patient proceeded to laparoscopic appendicectomy with resection of the fistula tract. Histopathology demonstrated a mid-appendiceal mucinous neoplasm, with a benign enterocutaneous fistula tract communicating with the distal, non-malignant portion of the appendix. We provide an overview of the literature and highlight the need to consider appendiceal mucinous neoplasm as a differential in the management of spontaneous right iliac fossa collections and fistulae.

Standardization of the pathologic diagnosis of appendiceal mucinous neoplasms

Although the understanding of appendiceal mucinous neoplasms (AMNs) and their relationship with disseminated peritoneal mucinous disease have advanced, the diagnosis, classification, and treatment of AMNs are still confusing for pathologists and clinicians. The Gastrointestinal Pathology Study Group of the Korean Society of Pathologists (GPSG-KSP) proposed a multicenter study and held a workshop for the “Standardization of the Pathologic Diagnosis of the Appendiceal Mucinous Neoplasm” to overcome the controversy and potential conflicts. The present article is focused on the diagnostic criteria, terminologies, tumor grading, pathologic staging, biologic behavior, treatment, and prognosis of AMNs and disseminated peritoneal mucinous disease. In addition, GPSG-KSP proposes a checklist of standard data elements of appendiceal epithelial neoplasms to standardize pathologic diagnosis. We hope the present article will provide pathologists with updated knowledge on how to handle and diagnose AMNs and disseminated peritoneal mucinous disease.

Management of Low-Grade Appendiceal Mucinous Neoplasms (LAMN): An International Survey of Surgeons Performing CRS and HIPEC

BACKGROUND

Low-grade appendiceal mucinous neoplasms (LAMN) are commonly managed by community surgeons at diagnosis. There is variability in the treatment of LAMN, both by community and specialist providers. We assessed current management practices for LAMN across surgeons with expertise in peritoneal surface malignancies (PSM).

METHODS

An online survey was sent to 106 international surgeons specializing in PSM. The survey assessed demographics, favored pre-referral management, and definitive management practices for LAMN.

RESULTS

The response rate was 40% (67% USA, 33% international). Respondents had performed a median of 18 (interquartile range [IQR] 7.75-29) HIPEC cases in the last year, of which 10 (IQR 4-20) were for LAMN. Ninety-three percent reported more than half of LAMN referrals had already undergone surgery-an estimated 50% appendectomy and 20% right hemicolectomy (RH). No surgeon respondents supported performing right hemicolectomy before referral. For LAMN confined to the appendix, 86% of respondents would definitively treat with appendectomy. In the presence of mucinous implants, 24% would observe after appendectomy and 76% would proceed with HIPEC. All would perform HIPEC if implants contained tumor cells. When LAMN involved the appendiceal base, 67% of respondents would proceed with partial cecectomy, while 33% favored RH.

CONCLUSIONS

Pre-referral management of LAMN is not standardized and 20% of patients were referred to a surgeon who performs CRS/HIPEC after a right hemicolectomy that would not have been recommended. Management of LAMN by surgeons who treat PSM is also variable. Long-term data and identification of prognostic features are necessary to generate consensus on the optimal management of these complex patients.

The Role of Hyperthermic Intraperitoneal Chemotherapy for Non-colorectal Peritoneal Surface Malignancies

BACKGROUND

Peritoneal carcinomatosis, from a variety of gastrointestinal and gynecological malignancies, has been historically challenging to treat and there remains a wide range of biologic aggressiveness in these patients. Malignancies commonly associated with PC include those of colorectal, appendiceal, gastric, ovarian, sarcoma, small intestinal, and primary peritoneal origin among others. Advances in our understanding of this unique disease process have led to significant interest in cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) as an emerging treatment option. The goal of CRS-HIPEC is to remove all visible macroscopic disease while preserving organ function, and then treat microscopic disease through perfusion of the peritoneal cavity with heated chemotherapy.

PURPOSE

Although recent reviews have focused on the management of peritoneal carcinomatosis secondary to colorectal cancer given the publication of several recent randomized controlled trials, the purpose of the current review is to summarize the evidence on CRS-HIPEC for non-colorectal peritoneal surface malignancies, including appendiceal neoplasms, malignant peritoneal mesothelioma, gastric cancer, and ovarian cancer.

RESULTS

While retrospective studies have clarified the importance of prognostic factors such as the peritoneal carcinomatosis index, completeness of cytoreduction, histopathological characteristics, and lymph node positivity, the lack of convincing level 1 evidence for the use of CRS-HIPEC has led to it remaining a highly controversial topic.

CONCLUSION

The decision to utilize CRS-HIPEC should involve a multidisciplinary team approach and evaluation of prognostic factors to balance the short-term morbidity of the operation with maximum long-term benefits. Large, multi-institutional groups and ongoing trials hold promise for clarifying the role of CRS-HIPEC in peritoneal surface malignancies.

Women survive longer than men undergoing cytoreductive surgery and HIPEC for appendiceal cancer

BACKGROUND

We hypothesize that women undergoing cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for peritoneal carcinomatosis from appendiceal cancer will have a survival advantage compared to men.

METHODS

The National Cancer Database (NCDB) public user file (2004-2014) was used to select patients with PC undergoing CRS and HIPEC from appendiceal cancer. Univariate and multivariable analyses were performed.

RESULTS

1,190 patients with PC from appendiceal cancer underwent HIPEC and CRS. OS was significantly longer for women than for men, with mean and median OS being 73.8 months and 98.2 months for women vs 58.7 months and 82.5 months for men, respectively (p = 0.0032). On multivariable analysis, male sex (HR: 1.444, 95% CI: 1.141-1.827, p = 0.0022) and increasing age (HR: 1.017, 95% CI: 1.006-1.027, p = 0.0017) were both found to be independent risk factors for worse OS.

CONCLUSION

Women undergoing CRS and HIPEC for PC from appendiceal origin live longer than men undergoing the same treatment. Increasing age was also found to be independent risk factors for worse survival.

Updated staging and patient outcomes in low-grade appendiceal mucinous neoplasms

Low-grade appendiceal mucinous neoplasms (LAMNs) exhibit drastically different clinical course and prognosis depending on tumor stage, particularly as it relates to the extent and cellularity of peritoneal involvement. In this context, recent changes in staging guidelines have sought to clarify criteria for pT and pM categories. This study's aim was to identify clinicopathological features associated with patient outcomes, especially as they pertain to updated stage groups. We reviewed LAMNs from 192 patients (mean age: 56.9 years, 119 (62.0%) women). The tumors consisted of 66 (34.4%) pTisM0, 16 (8.3%) pT3M0, 16 (8.3%) pT4aM0, 27 (14.1%) pTxM1a, and 67 (34.9%) pTxM1b cases. In multivariate analysis, only gross perforation was significantly associated with higher TNM group stage (p = 0.001; OR 3.3, 95% CI: 1.7-6.4). Of 165 (85.9%) patients with clinical follow-up, 51 (30.9%) had disease progression (over a mean 33.7 months, range: 4.7-121.7), whereas over significantly longer follow-up (mean 48.7 months, range: 3.1-143.9; p = 0.004), 114 (69.1%) patients did not. In multivariate analysis, higher TNM stage was significantly associated with disease progression (p = 0.029; OR 18.3, 95% CI: 1.4-246.0). In Kaplan-Meier analysis, none of 74 patients with disease limited to the appendix (pM0), 6 of 27 (22.2%) cases with peritoneal involvement by acellular mucin only (pM1a), and 45 of 64 (70.3%) tumors with intraperitoneal deposits containing neoplastic cells (pM1b) showed disease progression (p < 0.001). These differences in progression-free survival among TNM groups persisted when limiting the analysis to patients who had undergone successful cytoreductive surgery (p = 0.050). Finally, in four patients (all with pM1b disease) death was attributed to disease progression whereas there was no disease-specific mortality in the pM0 and pM1a groups (p = 0.020). These data support the designation of LAMNs with acellular peritoneal mucin as having an intermediate prognosis between cases limited to the appendix and those with intraperitoneal deposits containing neoplastic epithelium.

Integrated clinico-molecular profiling of appendiceal adenocarcinoma reveals a unique grade-driven entity distinct from colorectal cancer

BACKGROUND

Appendiceal adenocarcinoma (AA) is an orphan disease with unique clinical attributes but often treated as colorectal cancer (CRC). Understanding key molecular differences between AA and CRC is critical.

METHODS

We performed retrospective analyses of AA patients (N = 266) with tumour and/or blood next-generation sequencing (NGS) (2013-2018) with in-depth clinicopathological annotation. Overall survival (OS) was examined. For comparison, CRC cohorts annotated for sidedness, consensus molecular subtypes (CMS) and mutations (N = 3283) were used.

RESULTS

Blood-NGS identified less RAS/GNAS mutations compared to tissue-NGS (4.2% vs. 60.9%, P < 0.0001) and showed poor concordance with tissue for well-/moderately differentiated tumours. RAS (56.2%), GNAS (28.1%) and TP53 (26.9%) were most frequent mutations. Well/moderately differentiated tumours harboured more RAS (69.2%/64.0% vs. 40.5%) and GNAS (48.7%/32.0% vs. 10.1%) while moderate/poorly differentiated tumours had more TP53 (26.0%/27.8% vs. 7.7%) mutations. Appendiceal adenocarcinoma (compared to CRC) harboured significantly fewer APC (9.1% vs. 55.4%) and TP53 (26.9% vs. 67.5%) and more GNAS mutations (28.1% vs. 2.0%) (P < 0.0001). Appendiceal adenocarcinoma mutation profile did not resemble either right-sided CRC or any of the four CMS in CRC. High grade, but no mutation, was independently predictive of survival.

CONCLUSION

Integrated clinico-molecular profiling of AA identified key molecular drivers distinct from CRC. Appendiceal adenocarcinoma has a predominantly grade-driven biology that trumps mutations.

Incidental appendiceal mucinous neoplasm mimicking a left adnexal mass: A case report

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Equivocal signs and symptoms along with anatomical position of appendiceal mucinous neoplasm (AMN) makes it difficult to diagnose.

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Pre-operative, findings like ‘onion skin’ sign on ultrasonography and ‘volcano sign’ on colonoscopy are specific for appendiceal mucocele.

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Primary AMN is rarely diagnosed before operation and histopathological examination.

•

AMN can mimic ovarian tumors. Consider AMN in the differential diagnosis for any pelvic mass in elderly female patients.

Introduction

Appendiceal mucinous neoplasm is a rare type of appendiceal tumors which can present in a variety of symptoms and is difficult to diagnose. Preoperative diagnosis depends mainly on diagnostic imaging such as ultrasonography and computerized tomography (CT) scan. This uncommon case report discusses an appendiceal mucinous neoplasm mimicking a left adnexal mass on presentation, physical examination and diagnostic imaging findings.

Presentation of case

This is a 61-year-old female found to have a large left adnexal mass during follow up ultrasonography. The patient refused further imaging, and during laparotomy, she was found to have an appendicular mucocele with normal left and right ovaries.

Discussion

Appendectomy was done and the final pathology came as appendiceal mucinous neoplasm. Her post-operative course and 3 years follow up were uneventful.

Conclusions

The equivocal signs and symptoms along with the anatomical position of appendiceal mucocele makes it difficult to diagnose and can mimic other types of tumors. Therefore, it should be considered in the deferential diagnosis of lower abdominal and pelvic masses.

Appendiceal Mucinous Neoplasm: Nurse Education About a Rare and Complex Disease

BACKGROUND

Appendiceal mucinous neoplasms (AMNs) are a rare and complex spectrum of disease involving a mucinous tumor within the appendix, which can range from benign to malignant. If not limited to the appendix, the mucinous tumor can spread diffusely throughout the peritoneum.

OBJECTIVES

Because of the low incidence of AMN, this study describes the diagnosis and treatment process for this disease, which is not well known to most care providers.

METHODS

An extensive analysis of the current literature, including incidence, diagnosis, and surgical treatment, was performed. A review of the pre- and postoperative needs for patients undergoing surgery was also conducted.

FINDINGS

There is minimal information in the nursing literature about AMN and the complexity of surgical management. Nurses play an important role in caring for these patients and their unique needs both before and after surgery.

Germline whole exome sequencing of a family with appendiceal mucinous tumours presenting with pseudomyxoma peritonei

Background

Familial cases of appendiceal mucinous tumours (AMTs) are extremely rare and the underlying genetic aetiology uncertain. We identified potential predisposing germline genetic variants in a father and daughter with AMTs presenting with pseudomyxoma peritonei (PMP) and correlated these with regions of loss of heterozygosity (LOH) in the tumours.

Methods

Through germline whole exome sequencing, we identified novel heterozygous loss-of-function (LoF) (i.e. nonsense, frameshift and essential splice site mutations) and missense variants shared between father and daughter, and validated all LoF variants, and missense variants with a Combined Annotation Dependent Depletion (CADD) scaled score of ≥10. Genome-wide copy number analysis was performed on tumour tissue from both individuals to identify regions of LOH.

Results

Fifteen novel variants in 15 genes were shared by the father and daughter, including a nonsense mutation in REEP5. None of these germline variants were located in tumour regions of LOH shared by the father and daughter. Four genes (EXOG, RANBP2, RANBP6 and TNFRSF1B) harboured missense variants that fell in a region of LOH in the tumour from the father only, but none showed somatic loss of the wild type allele in the tumour. The REEP5 gene was sequenced in 23 individuals with presumed sporadic AMTs or PMP; no LoF or rare missense germline variants were identified.

Conclusion

Germline exome sequencing of a father and daughter with AMTs identified novel candidate predisposing genes. Further studies are required to clarify the role of these genes in familial AMTs.

Incidence and survival trends for appendiceal mucinous adenocarcinoma: an analysis of 3237 patients in the Surveillance, Epidemiology, and End Results database

Aim: To characterize the epidemiology of appendiceal mucinous adenocarcinoma. Methods: Prognostic factors were evaluated with univariate and multivariate analyses. The results were used to generate a nomogram. Results: The incidence of appendiceal mucinous adenocarcinoma showed a significant upward trend. Multivariate Cox analysis identified 11 independent prognostic factors. The nomogram was based on independent risk factors that were significant in multivariate Cox analysis, and the concordance-index for overall survival and cancer-specific survival were 0.76 (95% CI: 0.71-0.79) and 0.74 (95% CI: 0.70-0.79), respectively. Conclusion: Advanced age, single relationship status, male sex, black race, the presence of distant and regional lymph node metastases, poor differentiation or lack of differentiation, advanced SEER extent of disease, cancer-directed surgery and chemotherapy were independently associated with prognosis.

Impact of nonappendiceal cancer-specific death on overall survival: a competing risk analysis

Aim: The occurrence of nonappendiceal cancer-specific death (non-ACSD) and its impact on overall survival are unclear. Methods: Patients were extracted from the Surveillance, Epidemiology, and End Results. Results: Nearly 33.2 and 24.0% patients suffered ACSD and non-ACSD. In a Cox proportional-hazards model, unmarried patients were at greater risk of mortality than were married patients. In a competing risk model, unmarried patients were at greater risk of non-ACSD than were married patients, but the risk of ACSD did not differ significantly according to marriage status. Conclusion: The overall survival of patients with appendiceal cancer was reduced by non-ACSD. A competing risk model was more predictive of the prognosis than was a Cox proportional hazards model.

Nomogram to predict overall survival and disease-specific survival with appendiceal mucinous adenocarcinoma

To predict the survival of appendiceal mucinous adenocarcinoma (AMA) by prognostic nomogram.A total of 3234 patients with AMA were collected from the Surveillance, Epidemiology, and End Results (SEER) database from 1973 to 2015. Univariate and multivariate Cox proportional hazards (PH) regression analyses were used to generate independent prognostic factors. These variables were included in the nomogram to predict overall survival (OS) and disease-specific survival (DSS) at 1-, 3-, and 5- years. These data are validated both internally and externally. The consistency index (C-index) and calibration chart were used to estimate the accuracy of the nomogram.The study cohort was randomly divided into the training (n = 2155) and validation group (n = 1799). According to univariate and multivariate analyses, age at diagnosis, marital status, sex, histological differentiation, SEER extent of disease, number of local lymph nodes examined, whether they were positive, and surgical methods were independent prognostic factors for OS and DSS. These factors were incorporated into the nomogram. Internal validation in the training cohort showed that the C-index values for nomogram predictions of OS and DSS were 0.73 (95% CI 0.70-0.76) and 0.77 (95% CI 0.73-0.81), respectively. Similarly, the corresponding C-index values in the external validation cohort were 0.76 (95% CI 0.70-0.81) and 0.75 (95% CI 0.71-0.80). The Calibration plots revealed that the actual survival and nomogram prediction had a good consistency.Build a nomogram in the SEER database to predict OS and DSS in patients with AMA. It can provide accurate and personalised survival prediction for clinicians and patients.

Lymphovascular Invasion Is Associated with Lymph Node Involvement in Small Appendiceal Neuroendocrine Tumors

BACKGROUND

Appendiceal neuroendocrine tumors (NETs) are incidentally found in up to 1% of appendectomy specimens. The association of lymphovascular invasion (LVI) with risk of regional lymph node involvement is unclear.

METHODS

From the National Cancer Database, 2004-2015, this study identified patients who had tumors 2 cm or smaller with one or more lymph nodes (LNs) pathologically evaluated. The histology was defined as typical, goblet cell, or composite NETs. Patient demographics, tumor characteristics, and treatment variables were analyzed.

RESULTS

The histologies for the 1767 identified patients were typical (n = 921, 52.1%), goblet cell (n = 556, 31.5%), and composite (n = 290, 16.4%). The tumor grades were low (70.4%), moderate (18.6%), and high (11%). The overall LN positivity was 17%. Of 1052 tumors evaluated, 215 (20.4%) had LVI. Overall survival decreased with node involvement (mean 84 vs. 124 months; p < 0.0001, log-rank). In the multivariate logistic regression analysis, LVI was independently associated with node involvement [odds ratio (OR) 5.0; p < 0.0001] after adjustment for patient age and tumor histologic subtype, size, and grade. In the subset analysis of typical NETs, tumor size of 1-2 cm (ref. < 1 cm; OR 5.5; p < 0.001) and presence of LVI (ref. absence of LVI; OR 4.8; p < 0.0001) were the only factors independently associated with LN involvement.

CONCLUSIONS

Node involvement is associated with worse overall survival in appendiceal NETs. The presence of LVI was strongly associated with lymph node involvement. An appendectomy specimen showing LVI should prompt strong consideration of colectomy with regional lymphadenectomy even for small, typical appendiceal NETs.

Obstruction-Free Survival Following Operative Intervention for Malignant Bowel Obstruction in Appendiceal Cancer

BACKGROUND

Patients with peritoneal metastases from appendiceal cancer are at high risk of malignant bowel obstruction (MBO), which is associated with significant morbidity and mortality. There are no definitive treatment guidelines regarding operative intervention for MBO. We sought to evaluate the efficacy and safety of operative intervention in this population.

METHODS

We identified patients with peritoneal metastases from appendiceal cancer who underwent surgery for MBO at our institution between 2011 and 2018. Baseline characteristics, postoperative complications, and follow-up data were collected. The primary endpoint was obstruction-free survival (OFS). Other endpoints were postoperative recovery of bowel function, 60-day Clavien-Dindo (CD) morbidity, and overall survival (OS).

RESULTS

Twenty-six patients underwent operative treatment for MBO, of whom 14 had high-grade (HG) histology and 12 had low-grade (LG) histology. Seven (25.9%) patients had severe (CD grade 3 or higher) 60-day complications, including one (3.8%) postoperative death. All remaining patients had return of bowel function and resumed oral intake during hospitalization. Six (23.1%) patients had repeat admissions for MBO after surgery. Median OFS was 17.0 months (95% confidence interval [CI] 2.3-31.8), and median OS was 18.5 months (95% CI 3.6-33.3) following surgery.

CONCLUSION

In this carefully selected group of patients with peritoneal metastases from appendiceal cancer, surgery for MBO provided durable palliation with acceptable morbidity.

Appendiceal neoplasm risk associated with complicated acute appendicitis-a population based study

PURPOSE

Appendiceal tumors are rare, but high neoplasm rates have been reported at interval appendectomy after periappendicular abscess. Non-operative management of uncomplicated acute appendicitis has shown promising results. The data on appendiceal tumor incidence and presentation among acute appendicitis patients is limited, especially in patient cohorts differentiating between uncomplicated and complicated acute appendicitis. Objective was to assess appendiceal tumor incidence and tumor association to appendicitis in patients with uncomplicated and complicated acute appendicitis.

METHODS

This nationwide population-based registry study was conducted from 2007 to 2013. The Finnish Cancer Registry and the National Institute for Health Registry were used to combine data on all appendiceal tumors and acute appendicitis diagnosis with medical reports evaluated at eight study hospitals.

RESULTS

Altogether, 840 appendiceal tumors were identified, and out of these, 504 patient reports were reviewed, including 472 patients in this study. Tumor was diagnosed at appendectomy for suspected acute appendicitis in 276 patients (58%). In the whole study, histologically acute appendicitis and tumor were both present in 53% (n = 250), and out of these, 41% (n = 102) were complicated and 59% (n = 148) uncomplicated acute appendicitis. The associated tumor risk was significantly higher in complicated acute appendicitis compared with uncomplicated cases (3.24% vs. 0.87%, p < 0.001). Overall tumor prevalence among acute appendicitis patients was 1.24%.

CONCLUSIONS

Appendiceal tumor prevalence in acute appendicitis was low. Tumor risk was significantly higher in complicated acute appendicitis compared with uncomplicated acute appendicitis. The risk of missed appendiceal tumors related to antibiotic therapy of uncomplicated acute appendicitis is very low.

Appendiceal Mucinous Neoplasms: Diagnosis and Management

OBJECTIVE

Appendiceal mucinous neoplasms (AMNs) are a rare and heterogeneous disease for which clinical management is challenging. We aim to review the literature regarding modalities of treatment to guide the management of AMNs.

METHODS AND REVIEW CRITERIA

We conducted a PubMed search in February 2016 for English-language publications, using the terms "appendiceal," "appendix," "carcinoma," "cancer," "mucinous," "treatment," "genes," "target," "genomic," and terms listed in the articles' subheadings. Published reports and abstracts from the American Society of Clinical Oncology meetings were also searched.

RESULTS

In this review, we summarize current data and controversies in AMN classification, clinical presentation, molecular alterations, treatment outcomes with regard to cytoreductive surgery, hyperthermic intraperitoneal chemotherapy (HIPEC), and the role of systemic chemotherapy.

CONCLUSION

Appendiceal mucinous neoplasms are a heterogeneous group of tumors with a rising incidence. Treatment is based on stage and histology. Low-grade tumors are treated surgically with resection of the primary site in early stage disease, or peritoneal debulking and HIPEC in patients with advanced stage disease. Treatment of high-grade tumors requires further prospective trials, and options include debulking surgery and HIPEC with or without preoperative chemotherapy. Trials evaluating novel therapies based on the molecular profiling of AMN tumors are needed to evaluate therapeutic options in patients who are not surgical candidates.

IMPLICATIONS FOR PRACTICE

This review provides a reference to guide gastroenterologists, pathologists, surgeons, and oncologists in the management of appendiceal mucinous neoplasms (AMNs), a rare and heterogeneous disease with no consensus on histologic classification or guidelines for treatment algorithms. This review summarizes all AMN classifications and proposes a treatment algorithm based on stage and histology of disease.

Mucinous appendiceal neoplasms: Incidence, diagnosis and surgical treatment

INTRODUCTION

Mucinous tumors of the appendix are a rare pathology, with a prevalence below 0.5%. Clinical presentation usually occurs during the sixth decade of life, and mucinous tumors can clinically mimic acute appendicitis. The aim of this study is to describe the clinical and demographic variables, therapeutic procedure and diagnosis of these tumors. We analyze the association between mucinous tumors and pseudomyxoma peritonei (PP), as well as the association with colorectal and ovarian tumors.

METHODS

A retrospective study was performed including patients who underwent an appendectomy between December 2003 and December 2014.

RESULTS

Seventy-two mucinous tumors of the appendix were identified among 7.717 patients reviewed, resulting in a prevalence of 0.9%. Mean age at presentation was 64 years, 62% patients were female and 38% males. An incidental diagnosis was made in 43% of patients. Mucinous tumors of low malignant potential were significantly related to the presence of pseudomyxoma peritonei, identified in 16 (22%) of the cases. We also observed an increased risk of ovarian mucinous tumors in patients with a diagnosis of appendiceal mucinous neoplasm. In our sample, 22 (30.5%) patients showed a synchronous or metachronous colorectal cancer.

CONCLUSIONS

Appendiceal mucinous tumors are frequently an incidental finding. The diagnosis of mucinous tumors of low malignant potential is a factor associated with the development of pseudomyxoma peritonei. Histologic tumor grade and the presence of peritoneal dissemination will determine surgical treatment that can vary, from appendectomy to cytoreductive surgery.

Proactive Management for Gastric, Colorectal and Appendiceal Malignancies: Preventing Peritoneal Metastases with Hyperthermic Intraperitoneal Chemotherapy (HIPEC)

An integrated treatment strategy using peritonectomy procedures plus hyperthermic intraperitoneal chemotherapy (HIPEC) is now a clinical standard of care in selected patients with peritoneal metastases and primary peritoneal tumors. This comprehensive approach can offer many patients, who hitherto had no hope of cure, a good quality of life and survival despite limited morbidity. The increasingly successful results and chance of interfering in the natural history of disease has prompted research to develop for some clinical conditions a therapeutic strategy designed to prevent malignant peritoneal dissemination before it becomes clinically evident and treat it microscopically (tertiary prevention). The main factor governing successful cytoreductive surgery and predicting outcome is the extent of peritoneal spread assessed with the peritoneal cancer index (PCI). In peritoneal metastases from colorectal and gastric cancer the PCI score acquires a specific role acting as the cut-off between patients who can undergo curative surgery or palliation. Long-term results show that the only group enjoying favorable results are patients with limited disease (a statistical minority). By applying to appropriately selected patients with primary malignancies a proactive management strategy including HIPEC we can treat patients with microscopic peritoneal dissemination and therefore at PCI 0. Among treated conditions pseudomyxoma peritonei enjoys the best results. But a major future advance comes from identifying among lesions at major risk of pseudomyxoma.