Disseminated peritoneal adenomucinosis and peritoneal mucinous carcinomatosis. A clinicopathologic analysis of 109 cases with emphasis on distinguishing pathologic features, site of origin, prognosis, and relationship to "pseudomyxoma peritonei"

Appendix-derived Pseudomyxoma Peritonei (PMP): Molecular Profiling Toward Treatment of a Rare Malignancy

OBJECTIVES

Pseudomyxoma peritonei (PMP) is a rare malignancy originating from the appendix, characterized by disseminated mucinous tumor implants on peritoneal surfaces. We examined the role of multiplatform molecular profiling to study biomarker-guided treatment strategies for this rare malignancy.

METHODS

A total of 54 patients with appendix-derived PMP were included in the study. Tests included one or more of the following: gene sequencing (Sanger or next generation sequencing), protein expression (immunohistochemistry), and gene amplification (C/fluorescent in situ hybridization).

RESULTS

Targeted sequencing of 47 genes detected variants in KRAS (81%), GNAS (74%), SMAD4 (16%), and ATM (16%). Mutations were found at low frequencies (n=1 to 2) in APC, BRAF, PIK3CA, MLH1, and TP53. GNAS and KRAS co-occurrence was found in 87%. Protein overexpression was found in epidermal growth factor receptor (83%), cyclooxygenase-2 (73%), cMET (63%), cKIT (58%), and platelet-derived growth factor receptor alpha (58%). Immune checkpoint expression was found in 36% (programmed cell death protein 1) and 18% (programmed death-ligand 1). Surrogate markers of cell proliferation were found at low rates (TLE3 23%, TOP2A 22%), consistent with the slow-growing biology of PMP. Phosophatase and tensin homolog was intact (wild type [100%]) and positive (immunohistochemistry [80%]). Patients exhibited stable microsatellite status and mismatch repair proficiency (93%). Importantly, multidrug resistance protein expression was elevated (100% BCRP, 94% MRP1, 88% PGP). Markers for gemcitabine (RRM1), fluorouracil (TS), oxaliplatin (ERCC1), and irinotecan (TOPO1) chemosensitivities were detected at favorable rates: 93%, 87%, 77% and 65%, respectively.

CONCLUSIONS

Molecular profiling by multiple platforms identified potential therapies for the nontargetable KRAS-mutated population. The role of cMET-targeted therapeutics and immune checkpoint inhibitors merits further investigation. Biomarker-guided selection of cytotoxic chemotherapies may facilitate efficacy to systemic treatment.

Discrimination of low- and high-grade appendiceal mucinous neoplasms by targeted sequencing of cancer-related variants

DNA was obtained from matching micro-dissected, primary tumor cells, paired metastases, and peripheral blood mononuclear cells (germline) from patients with appendiceal mucinous neoplasms. We compared specimens from patient cohorts comprising low-grade adenomucinous neoplasm versus high-grade mucinous adenocarcinoma using a targeted, amplicon sequencing panel of 409 cancer related genes (Ion Torrent Comprehensive Cancer Panel, Thermo-Fisher, Waltham, MA). Copy number variants, single nucleotide variants and small insertions/deletions were identified using a multiplex algorithm pipeline (GATK, VarScan2, MuTect2, SIFT, SIFT-INDEL, PolyPhen-2, Provean). There were significantly more damaging variants in high-grade versus low-grade tumor cohorts. Both cohorts contained damaging, heterozygous germline variants (catenin β1; notch receptor 1 and 4) in pathways associated with cell-lineage specification (WNT, NOTCH). Damaging, somatic KRAS proto-oncogene, GTPase mutations were present in both cohorts, while somatic GNAS complex locus mutations were confined to low-grade neoplasms. Variants predominantly affected transcription factors, kinases, and stem cell signaling molecules in canonical pathways including epithelial to mesenchymal transition, stem cell pluripotency, p53, PTEN, and NF-қB signaling pathways. High-grade tumors demonstrated MYC proto-oncogene, bHLH transcription factor (MYC) and death domain associated protein (DAXX) amplification and damaging somatic variants in tumor protein p53 (TP53), likely to amplify an aggressive phenotype. Damaging APC, WNT signaling pathway regulator (APC) deletions were identified in metastatic tissue of both cohorts suggesting a role in invasive disease. Our data suggest that germline dysregulation of WNT and/or NOTCH pathways predisposes patients toward a secretory cell phenotype (i.e., goblet-like cells) upon acquisition of somatic KRAS mutations. Additional somatically acquired variants activating oncogenes MYC and DAXX and inhibiting the critical tumor suppressor, tumor protein TP53, were consistent with manifestation of a high-grade phenotype. These additional changes within the epithelial to mesenchymal transition signaling network (WNT, NOTCH, RAS/ERK/PI3K, PTEN, NF-қB), produce aggressive high-grade tumor characteristics by actively driving cells towards dedifferentiation, proliferation, and migration.

Systemic chemotherapy before cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) in patients with high-grade mucinous carcinoma peritonei of appendiceal origin

BACKGROUND

The role of systemic chemotherapy (SC) before cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) in appendiceal high-grade mucinous carcinoma peritonei (HGMCP) is controversial. We analyzed the effect of SC prior to CRS/HIPEC in HGMCP.

METHODS

A prospective database of CRS/HIPEC procedures for HGMCP without signet ring cells and with signet ring cells (HGMCP-S) from 1998 to 2017 was reviewed. Exclusion criteria was prior surgery >5 regions or >2 regimens of prior SC. Perioperative variables were analyzed.

RESULTS

There were 140 HGMCP/HGMCP-S identified: 64 with prior SC (preSC) and 76 without (noSC). Groups were balanced for lymph node status, complete cytoreduction rate, disease burden, complications, and postoperative SC. PreSC had more HGMCP-S, moderately/poorly differentiated histology, and longer time-to-surgery (median: 6 vs 2 months, p < 0.001). Median overall survival (mOS) was 40 vs 86 and median progression-free survival (mPFS) was 19 vs 43 months for preSC vs noSC, respectively (p = 0.006 and p = 0.007). In HGMCP-S subanalysis, mOS was 25 vs 39 and mPFS 16 vs 29 months for preSC vs noSC, respectively (p = 0.188 and p = 0.063). In moderately/poorly differentiated histology subanalysis, mOS was 38 vs 56 and mPFS 18 vs 29 months in preSC vs noSC, respectively (p = 0.199 and 0.082). Prior SC was not linked to improved OS or PFS in non-signet ring HGMCP or well-differentiated histology subanalysis.

CONCLUSION

Prior SC was not associated with less disease burden, better cytoreduction rates, or improved clinical outcomes in HGMCP, regardless of histopathologic subtype. Traditional SC agents may not be effective in HGMCP in the neoadjuvant setting.

Mucinous appendiceal neoplasms: classification, imaging, and HIPEC

Recent advances, specifically cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC), offer advantages compared to the traditional therapeutic approach of systemic chemotherapy in the treatment of peritoneal carcinomatosis from mucinous appendiceal neoplasms (MAN). This review provides an up-to-date, comprehensive summary of the histologic classification of MAN, reviews common imaging findings of mucoceles and pseudomyxoma peritonei, and describes the radiologist's role in the multidisciplinary care team in quantifying disease and in helping select patients for definitive surgery.

Pseudomyxoma peritonei induced by low-grade appendiceal mucinous neoplasm accompanied by rectal cancer: a case report and literature review

Background

Pseudomyxoma peritonei (PMP) is a disease involving the peritoneum characterized by the production of large quantities of mucinous ascites. PMP has a low incidence, is difficult to diagnose, and has a guarded prognosis. PMP induced by low-grade appendiceal mucinous neoplasm is extremely rare, and PMP accompanied by rectal cancer is even rarer.

Case presentation

We present a unique case of a 70-year-old male with PMP induced by low-grade appendiceal mucinous neoplasm accompanied by rectal cancer. The patient’s clinical, surgical, and histologic data were reviewed. The patient had persistent distended abdominal pain without radiating lower back pain, abdominal distension for 1 month, and no exhaustion or defecation for 4 days. A transabdominal ultrasound-guided biopsy was performed on the first day. The patient received an emergency exploratory laparotomy because of increased abdominal pressure. We performed cytoreductive surgery, enterolysis, intestinal decompression, special tumour treatment and radical resection of rectal carcinoma. The postoperative course was uneventful. The postoperative histological diagnoses were PMP, low-grade appendiceal mucinous neoplasm and rectal medium differentiated adenocarcinoma. At the 1-year follow-up visit, no tumour recurrence was observed by computed tomography (CT). We also performed a literature review.

Conclusions

We should be aware that PMP can rarely be accompanied by rectal cancer, which represents an easily missed diagnosis and increases the difficulty of diagnosis and treatment. Additionally, there are some typical characteristics of PMP with respect to diagnosis and treatment.

Factors influencing long-term survival after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for pseudomyxoma peritonei originating from appendiceal neoplasms

Background

Pseudomyxoma peritonei (PMP) is a rare disease, most commonly of appendiceal origin. Treatment consists of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS–HIPEC). The aim of this study was to identify prognostic factors for recurrence and survival.

Methods

This was an observational study using a prospectively designed database containing consecutive patients with PMP originating from the appendix, undergoing CRS–HIPEC at a tertiary referral centre between 1996 and 2015. Histopathological slides were reassessed. Cox regression was used for multivariable analyses.

Results

Of 225 patients identified, 36 (16·0 per cent) were diagnosed with acellular mucin, 149 (66·2 per cent) had disseminated peritoneal adenomucinosis (DPAM) and 40 (17·8 per cent) had peritoneal mucinous carcinomatosis (PMCA). The 5‐year overall survival (OS) rates were 93, 69·8 and 55 per cent respectively. Recurrence was observed in 120 patients (53·3 per cent), 39 of whom (17·3 per cent) were treated with a second CRS–HIPEC procedure. Factors independently associated with poor disease‐free survival were six or seven affected regions (hazard ratio (HR) 6·01, 95 per cent c.i. 2·04 to 17·73), incomplete cytoreduction (R2a resection: HR 1·67, 1·05 to 2·65; R2b resection: HR 2·00, 1·07 to 3·73), and more than threefold raised carcinoembryonic antigen (CEA) and/or carbohydrate antigen (CA) 19‐9 level (HR 2·31, 1·30 to 4·11). Factors independently associated with poorer OS were male sex (HR 1·74, 1·09 to 2·77), incomplete cytoreduction (R2a resection: HR 1·87, 1·14 to 3·08; R2b resection: HR 2·28, 1·19 to 4·34), and more than threefold raised CEA and/or CA19‐9 level (HR 2·89, 1·36 to 6·16).

Conclusion

CEA and CA19‐9 levels raised more than threefold above the upper limit identify patients with PMP of appendiceal origin and poorer survival.

A unique presentation of superinfected pseudomyxoma peritonei secondary to a low-grade appendiceal mucinous neoplasm

Background

Pseudomyxoma peritonei (PMP) is an uncommon condition characterized by diffuse mucinous material in the abdomen and pelvis, generally arising from a perforated epithelial neoplasm. Typically, the disease presents as suspected acute appendicitis, ovarian mass, abdominal distension, or ventral hernia. Our case represents a very rare presentation of superinfected PMP.

Case presentation

A 46-year-old female with a past medical history notable for depression, asthma, and uterine leiomyomas presented to an urgent care with 5 days of progressive abdominal pain, bloating, nausea, and subjective fevers. The patient had a diffusely tender abdomen, without peritonitis, was mildly tachycardic, and had a white blood cell count of 15 K. A CT of the abdomen/pelvis was consistent with PMP with a ruptured appendiceal mucocele versus PMP secondary to an adnexal ovarian neoplastic pathology with an infectious component. The patient initially improved on antibiotics but ultimately required two surgeries, the first of which controlled intraabdominal sepsis while the second permitted definitive management of PMP with cytoreductive surgery (CRS) and HIPEC.

Conclusion

Superinfected PMP is a rare entity with very few documented cases. A staged approach that incorporates clearing the peritoneal infection, with or without resection of the primary tumor, followed by rehabilitation and definitive surgery appears to be a safe and effective management strategy.

Pre- and post-operative antibiotics in conjunction with cytoreductive surgery and heated intraperitoneal chemotherapy (HIPEC) should be considered for pseudomyxoma peritonei (PMP) treatment

Pseudomyxoma peritonei (PMP) is a subtype of peritoneal carcinomatosis that is traditionally treated by cytoreductive surgery (CRS) followed by hyperthermic intraperitoneal chemotherapy (HIPEC). A growing body of evidence suggests that microbes are associated with various tumor types and have been found in organs and cavities that were once considered sterile. Prior and ongoing research from our consortium of PMP researchers strongly suggests that bacteria are associated with PMP tumors. While the significance of this association is unclear, in our opinion, further research is warranted to understand whether these bacteria contribute to the development, maintenance and/or progression of PMP. Elucidation of a possible causal role for bacteria in PMP could suggest a benefit for supplementation of antibiotics to current treatment protocols.

Combined Mucinous and Neuroendocrine Tumours of the Appendix Managed with Surgical Cytoreduction and Oxaliplatin-based Hyperthermic Intraperitoneal Chemotherapy

Appendiceal neoplasms account for 1% of appendectomy specimens. Common subtypes include mucinous cystadenoma, adenocarcinoma, and neuroendocrine tumors (NETs). The simultaneous presence of appendicular mucinous and NETs is a rare event. Depending on the tumors’ morphological distribution in the affected organ, they are qualified as either “collision” or “combined” tumours. We herein present the case of a 50-year-old male who presented with acute appendicitis and who was subsequently found to have pseudomyxoma peritonei (PMP) due to a perforated combined mucinous and neuroendocrine tumours. The patient was treated by right hemicolectomy and cytoreductive surgery (CRS) with oxaliplatin-based hyperthermic intraperitoneal chemotherapy (HIPEC). He was cancer free 20 months later. Due to the limited clinical experience with this presentation, no formal recommendations exist as to its management other than those applicable to each cancer alone. The efficacity of treatment on the long-term prognosis on these combined tumors is yet to be elucidated.

Pseudomyxoma Peritonei After a Total Pancreatectomy for Intraductal Papillary Mucinous Neoplasm With Colloid Carcinoma in Lynch Syndrome

We report a case of pseudomyxoma peritonei (PMP) arising in a 62-year-old male patient with Lynch syndrome (LS). The patient's medical history included an adenocarcinoma of the colon for which a right hemicolectomy was performed and a pancreatectomy due to an intraductal papillary mucinous neoplasm (IPMN) with invasive colloid carcinoma. It was considered that the PMP could be a metastasis of the earlier colonic or pancreatic carcinoma. The pancreatic carcinoma, colon carcinoma, and PMP tissues were examined, and immunohistochemical and molecular analyses were performed to determine the PMP origin. Histopathologic examination revealed morphological similarities with the pancreatic colloid carcinoma, and further immunohistochemical and molecular analyses, including a shared GNAS mutation, confirmed the pancreatic origin of the PMP. In conclusion, this is a unique case of a patient with LS presenting with PMP originating from an IPMN with invasive colloid carcinoma, several years after pancreatectomy. The present case has important diagnostic implications. The IPMN should be considered as a rare extracolonic manifestation of LS, and pancreatic carcinoma origin should be considered in patients presenting with PMP. This case report highlights the added value of molecular diagnostics in daily pathology practice.

Pseudomyxoma extraperitonei in horseshoe kidney masquerading as renal hilar tumor: a case report

Pseudomyxoma peritonei, a rare condition consisting of intraperitoneal mucinous tumors and ascites, most commonly arises from mucinous tumors of the appendix. Very rarely, mucinous deposits arise in the retroperitoneum without intraperitoneal involvement. This has been termed pseudomyxoma extraperitonei. It is a rare and poorly understood condition that is heterogeneous in its clinical behavior, and only a few cases presenting as localized disease in the retroperitoneum have been reported. In this paper, we report the first case of pseudomyxoma extraperitonei presenting as a simple renal hilar mass and mimicking a tumor of renal origin in a horseshoe-kidney patient. The patient underwent isthmusectomy and nephrectomy. Immunohistochemical staining suggested appendiceal origin. She remained alive without adjuvant therapy postoperatively, and no evidence of recurrence was present for 25 months.

Pseudomyxoma Peritonei: Presentation of Two Cases and Challenging Issues in the Literature

Pseudomyxoma peritonei (PMP) is a rather uncommon syndrome in oncology with a unique biological behavior and an estimated incidence of one to two cases per million per year. Clinically, it usually presents with a variety of unspecific signs and symptoms including abdominal pain and distention, ascites, or even bowel obstruction. Despite its intimidating clinical manifestation, PMP is characterized by satisfactory survival rates when treated with cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC). We present two interesting cases of PMP deriving from the appendix with a rather atypical presentation, which was successfully treated with cytoreduction and HIPEC. In addition, we intend to raise clinical suspicion on the diagnosis of PMP and comment on several challenging issues concerning the origin and classification of PMP.

Outcomes in Peritoneal Dissemination from Signet Ring Cell Carcinoma of the Appendix Treated with Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy

BACKGROUND

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) is standard treatment for peritoneal dissemination from appendiceal cancer (AC); however, its role in high-grade histopathologic subtypes (high-grade mucinous carcinoma peritonei [HGMCP] and HGMCP with signet ring cells [HGMCP-S]) is controversial due to their aggressive behavior. This study analyzed clinical outcomes of high-grade AC after CRS/HIPEC.

METHODS

A prospective database of CRS/HIPEC procedures for HGMCP performed from 1998-2017 was reviewed. Perioperative variables and survival were analyzed.

RESULTS

Eighty-six HGMCP and 65 HGMCP-S were identified. HGMCP had more positive tumor markers (TM) (CEA/CA-125/CA-19-9) than HGMCP-S (63% vs 40%, p = 0.005). HGMCP had higher Peritoneal Cancer Index (32 vs 26, p = 0.097) and was less likely to have positive lymph nodes (LN) than HGMCP-S (28% vs 69%, p = < 0.001). Complete cytoreduction was achieved in 84% and 83%, respectively. PFS at 3- and 5-years was 59% and 48% for HGMCP vs 31% and 14% for HGMCP-S. Median PFS was 4.3 and 1.6 years, respectively (p < 0.001). OS at 3- and 5-years was 84% and 64% in HGMCP vs 38% and 25% in HGMCP-S. Median OS was 7.5 and 2.2 years, respectively (p < 0.001). LN negative HGMCP-S had longer median PFS and OS than LN positive HGMCP-S (PFS: 3.4 vs 1.5 years, p = 0.03; OS: 5.6 vs 2.1 months, p = 0.021).

CONCLUSIONS

The aggressive histology of HGMCP-S is associated with poor OS, has fewer abnormal TM, and is more likely to have positive LN. However, CRS/HIPEC can achieve a 5-year survival of 25%, which may improve to 51% with negative LN.

Peritoneal Metastases from Appendiceal Cancer

The early symptoms of appendiceal cancer may mimic the clinical picture of appendicitis. Most patients are diagnosed incidentally during surgical exploration or late when peritoneal or systemic dissemination has already occurred, as colonoscopy rarely will diagnose an appendiceal cancer. Systemic/extraperitoneal metastases are distinctly unusual for appendiceal mucinous lesions.

Long term survival analysis after hyperthermic intraperitoneal chemotherapy with oxaliplatin as a treatment for appendiceal peritoneal carcinomatosis

BACKGROUND AND OBJECTIVES

Complete cytoreductive surgery (CRS) followed by hyperthermic intraperitoneal chemotherapy (HIPEC) have been proven to lengthen survival in appendiceal peritoneal carcinomatosis (PC-A). The aim of this study was to analyze survival results of this therapy in our institution over the last 10 years.

METHODS

Data was retrospectively reviewed and analyzed. Treatment consisted of CRS plus HIPEC with oxaliplatin. Ronnett's histologic classification was used (peritoneal mucinous carcinomatosis (PMCA), PMCA with intermediate features (PMCA-I) and disseminated peritoneal adenomucinosis (DPAM)). Overall survival (OS) and disease-free survival (DFS) estimates were calculated using Kaplan-Meier survival curves.

RESULTS

109 patients with PC-A underwent laparotomy with curative intent. Of those, 92 underwent CRS plus HIPEC. Median follow-up was 42 months. The 5 and 10-year OS rates for the HIPEC group were 82.2% and 76.5%. The 5 and 10-year OS estimates for DPAM and PMCA-I subgroups were 100% and 100%, 78.1% and 72.9%, respectively. For the PMCA subgroup, the 3 and 5-year OS were 61.4% and 40.1%, respectively. The 5 and 10-year DFS estimates were 71.9% and 42.7%.

CONCLUSION

CRS plus HIPEC with oxaliplatin represent an effective therapeutic approach for PC-A. Long term OS estimates for patients treated at our institution are encouraging.

Outcomes of Low-Grade Appendiceal Mucinous Neoplasms with Remote Acellular Mucinous Peritoneal Deposits

BACKGROUND

Occasionally, low-grade appendiceal mucinous neoplasms (LAMN) present with mucinous peritoneal deposits (MPD) localized to periappendiceal tissue or diffused throughout the peritoneum.

OBJECTIVE

This study was aimed at evaluating the relevance of mucin cellularity for predicting outcomes of LAMN with remote MPD.

METHODS

The records of patients with LAMN and remote MPD who underwent initial assessment at a comprehensive cancer center from 1990 to 2015 were reviewed, and diagnostic procedures, treatments, and outcomes were analyzed.

RESULTS

Of 48 patients included in the analysis, 19 had cellular MPD (CMPD) and 29 had acellular MPD. Of 33 patients who underwent cytoreductive surgery, 30 had a complete cytoreduction; the 3 patients with an incomplete cytoreduction had CMPD. In the follow-up period (median, 4 years), 6 patients died of the disease, all of whom had CMPD. Of 11 patients who had progression of disease, 10 had CMPD.

CONCLUSION

Cellularity of remote MPD is an important determinant of disease outcome in LAMN. Approaches such as active surveillance may have a role in selected patients with LAMN and AMPD.

A Patient With a Low-grade Mucinous Neoplasm Involving the Ovary and Pseudomyxoma Peritonei Originating in an Isolated Intestinal Duplication

A considerable number of mucinous ovarian tumors are metastatic from other primary tumors, mainly from the gastrointestinal tract, and primary malignant mucinous ovarian tumors are considered rare. Mucinous ovarian tumors occurring within the clinical syndrome of pseudomyxoma peritonei are assumed to almost always originate from the appendix. We describe a patient with a low-grade mucinous tumor involving the ovary in coexistence with pseudomyxoma peritonei, who underwent appendectomy 25 yr earlier. The tumor originated from a rare cystic gastrointestinal duplication found in the mesenteric fat showing adenomatous changes. This illustrates that even in absence of the appendix, mucinous ovarian tumors occurring with pseudomyoma peritonei rarely arise from the ovary.

Appendiceal Neoplasms

Appendiceal neoplasms are identified in 0.9 to 1.4% of appendiceal specimens, and the incidence is increasing. It has long been professed that neuroendocrine tumors (formerly carcinoids) are the most common neoplastic process of the appendix; recent data, however, has suggested a shift in epidemiology. Our intent is to distill the complex into an algorithm, and, in doing so, enable the surgeon to seamlessly maneuver through operative decisions, treatment strategies, and patient counseling. The algorithm for evaluation and treatment is complex, often starts from the nonspecific presenting complaint of appendicitis, and relies heavily on often subtle histopathologic differences.

Approach to pseudomyxoma peritonei

Pseudomyxoma peritonei (PMP) is a mucinous tumour of the appendix that spreads into the peritoneal cavity in the form of gelatinous deposits. The incidence of PMP is believed to be approximately 1-3 out of a million per year. Nonetheless, due to its indolent nature, it is usually discovered at an advanced stage and severely impacts quality of life. Curative treatment for PMP is complete cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC). An extensive literature review was conducted searching EMBASE, MEDLINE, PubMed, and Google Scholar databases for PMP in aims to delineate a clinical approach to diagnosis and treatment. Literature was limited to the years 2007-2018. We found the 5-year overall survival with CRS and HIPEC estimated to be between 23%-82% and rates of major complications as high as 24%. Therefore, it is important to appropriately stage and select patients that should undergo CRS with HIPEC. Modalities like MDCT radiological scores have been shown to have sensitivity and specificity of 94% and 81%, respectively, in being able to predict resectability and survival. Despite treatment, the disease often recurs. Tumor markers have significant potential for establishing prognosis pre-operatively, and this paper will review the most recent evidence in support of them.

Mucinous Neoplasm of the Appendix as a Mimic of Cystic Adnexal Pathology

Pelvic pain presents a common diagnostic conundrum with a myriad of causes ranging from benign and trivial to malignant and emergent. We present a case where a mucinous neoplasm of the appendix acted as a mimic for tubular adnexal pathology on imaging. With the associated imaging findings on ultrasound, computed tomography, and magnetic resonance imaging, we wish to raise awareness of mucinous tumors of the appendix when tubular right adnexal pathology is present both in the presence of pelvic or abdominal pain or when noted incidentally. Tubular pathology such as uncomplicated paraovarian cysts or hydrosalpinx is frequently treated conservatively with long-interval follow-up imaging or left to clinical follow-up. Thus, if incorrectly diagnosed as tubular pathology, an appendix mucocele or mucinous neoplasm of the appendix is likely to be undertreated. We wish to clarify some of the confusion around nomenclature and classification of the multiple entities that are comprised by the terms mucocele and mucinous tumor of the appendix.

Unusual case of intraluminal cecal recurrence of a low grade appendiceal mucinous neoplasm (LAMN)-Case report and brief literature review

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Penetration of the visceral peritoneum by a mucinous neoplasm consists the cardinal point in the management and prognosis.

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Patients with LAMN confined to the muscularis propria after histologic examination of the entire appendix (pTis) have essentially no risk of recurrence.

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There are no clear guidelines regarding appropriate management of appendiceal LAMNs with positive margins, especially when confined within the serosa.

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A simple cecectomy is traditionally suggested by some authors, but according to more recent data its necessity is debated.

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LAMN may rarely recur in the form of a polypoid protrusion into the cecal lumen and this may originate from the buried stump of the appendix on the ground of a positive margin.

Introduction

Appendiceal mucinous neoplasms exhibit a wide spectrum of clinical behavior, ranging from neoplasms which are relatively slow-growing but with considerable risk for recurrence and eventual death and those neoplasms that are highly aggressive with increased likelihood of early death. Clinical behavior depend mainly on mucinous neoplasms grading and staging.

Presentation of case

We present the incidental finding of a mucinous appendiceal neoplasm in a 52 years old woman during her follow up for an operated breast carcinoma. The patient underwent appendectomy and a low grade appendiceal mucinous neoplasm (LAMN) confined into the appendiceal wall was diagnosed. Resection margin showed fibrous replacement of the appendiceal wall and some acellular intraluminal mucin. Three months later the tumor recurred inside the cecal lumen and a right hemicolectomy was performed showing again a LAMN confined into the bowel wall.

Discussion

According to the latest AJCC eighth edition patients with pTis LAMN, as in our case, (LAMN confined to the muscularis propria after histologic examination of the entire appendix) have essentially no risk of recurrence. Moreover, some authors suggest follow up for LAMN confined into the appendix even with a positive surgical margin.

Conclusion

Rarely, LAMN may recur in the form of a polypoid protrusion into the cecal lumen and this recurrence may originate from the buried stump of the appendix, especially when the surgical margin is positive.

Genomic Landscape of Appendiceal Neoplasms

Purpose

Appendiceal neoplasms are heterogeneous and are often treated with chemotherapy similarly to colorectal cancer (CRC). Genomic profiling was performed on 703 appendiceal cancer specimens to compare the mutation profiles of appendiceal subtypes to CRC and other cancers, with the ultimate aim to identify potential biomarkers and novel therapeutic targets.

Methods

Tumor specimens were submitted to a Clinical Laboratory Improvement Amendments-certified laboratory (Foundation Medicine, Cambridge, MA) for hybrid-capture-based sequencing of 3,769 exons from 315 cancer-related genes and 47 introns of 28 genes commonly rearranged in cancer. Interactions between genotype, histologic subtype, treatment, and overall survival (OS) were analyzed in a clinically annotated subset of 76 cases.

Results

There were five major histopathologic subtypes: mucinous adenocarcinomas (46%), adenocarcinomas (30%), goblet cell carcinoids (12%), pseudomyxoma peritonei (7.7%), and signet ring cell carcinomas (5.2%). KRAS (35% to 81%) and GNAS (8% to 72%) were the most frequent alterations in epithelial cancers; APC and TP53 mutations were significantly less frequent in appendiceal cancers relative to CRC. Low-grade and high-grade tumors were enriched for GNAS and TP53 mutations, respectively (both χ² P < .001). GNAS and TP53 were mutually exclusive (Bonferroni corrected P < .001). Tumor grade and TP53 mutation status independently predicted OS. The mutation status of GNAS and TP53 strongly predicted OS (median, 37.1 months for TP53 mutant v 75.8 GNAS-TP53 wild type v 115.5 GNAS mutant; log-rank P = .0031) and performed as well as grade in risk stratifying patients.

Conclusion

Epithelial appendiceal cancers and goblet cell carcinoids show differences in KRAS and GNAS mutation frequencies and have mutation profiles distinct from CRC. This study highlights the benefit of performing molecular profiling on rare tumors to identify prognostic and predictive biomarkers and new therapeutic targets.

Current practice of Latin American centers in the treatment of peritoneal diseases with cytoreductive surgery with HIPEC

INTRODUCTION

A combination therapy of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) has been proposed as a treatment option in patients with peritoneal metastasis of colorectal, ovarian, gastric cancers and sarcomas and as a current standard treatment for pseudomyxoma peritonei and peritoneal mesothelioma. There is a need to standardize its indication, drugs selection along with their concentrations and ways to deliver peritoneal chemotherapy solutions for best outcomes.

AIM OF THE STUDY

To investigate the current practice of Latin American (LA) Centers in which peritoneal diseases (PD) are treated.

PATIENT AND METHODS

All centers from Latin American Registry of Peritoneal Diseases (LARPD) were invited to participate in a two rounds online survey, to describe their current practice in all indications of CRS with HIPEC for PD.

RESULTS

76 out of 84 LARPD's centers answered the survey, with a response rate of 90,5%. The results represent the current practice of 248 surgeons that are members of LARPD's centers, in 8 LA countries, that at the time of the study had treated 2682 patients with CRS with HIPEC. All current practice aspects including indications, contra-indications, patient selection, methods of peritoneal chemotherapy delivery and treatment protocols are described in this manuscript.

CONCLUSIONS

This survey is the first LA effort to publish current practice indications and treatment protocols of PD. Achieving consensus of best therapeutic options is essential to provide the best possible outcomes for patients with PD who could benefit from CRS with HIPEC therefore aiming at standardization of the procedure.

Predicting Survival After Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Appendix Adenocarcinoma

BACKGROUND

Appendix adenocarcinomas are rare tumors with propensity for peritoneal metastasis. Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy is an established treatment with curative intent, but, to date, studies reporting survival have been heterogeneous with regard to their patient groups (including other tumor types), interventions (not all patients receiving intraperitoneal chemotherapy), and follow-up (varying surveillance protocols).

OBJECTIVE

The aim of this study is to quantify the impact of this intervention on survival in a homogeneous group of patients with appendix adenocarcinoma receiving standardized treatment and follow-up, and to determine the impact of prognostic indicators on survival.

DESIGN

This is a retrospective analysis of a prospective database at a national peritoneal tumor center where all patients had their appendix pathology reviewed and management planned by a specialized peritoneal tumor multidisciplinary team.

MAIN OUTCOME MEASURES

Data were extracted on prognostic indicators including peritoneal cancer index, completeness of cytoreduction score, preoperative tumor markers, and histological features. Overall and disease event-free survival from the date of intervention were evaluated using Kaplan Meier curves and univariate Cox proportional hazards regression analysis.

RESULTS

A total of 65 patients underwent cytoreductive surgery with hyperthermic intraperitoneal chemotherapy for appendix adenocarcinoma between 2005 and 2015. Median follow-up was 44.3 months. The overall survival was 55.5% and disease event-free survival was 36.1% (5-year rate). Peritoneal Cancer Index <7, complete cytoreduction score of 0, and preoperative CEA of <6 were all associated with significantly higher overall and disease event-free survival. CA19-9 <38 and CA125 <31 were not associated with a significantly higher overall or disease event-free survival.

LIMITATIONS

The sample size was limited because of the rarity of this tumor type.

CONCLUSIONS

This study quantifies the impact of cytoreductive surgery with hyperthermic intraperitoneal chemotherapy on overall and disease event-free survival for appendix adenocarcinoma, identifying key prognostic indicators that may guide treatment. It supports the referral of these rare tumors to specialist centers with appropriate expertise for initial management and follow-up. See Video Abstract at http://links.lww.com/DCR/A595.

Signet Ring Carcinoma of the Appendix Presenting as Crohn's Disease in a Young Male

Primary signet ring cell carcinoma is a rare event in surgery. It looks like acute appendicitis and it is difficult to diagnose it on clinical grounds alone. The diagnosis is always confirmed by histopathology of a surgically removed appendix. A young man, 22 years old, presented with vomiting, diarrhea, and cramps in his abdomen without abdominal tenderness (mild abdominal discomfort in the right lower abdominal quadrant without signs of peritoneal irritation) during the previous month. The first endoscopic results showed only changes of mucosa that could be attributed to endoscopic and clinical representation of Crohn's disease. A few days after the initiation of the therapy with aminosalicylates and corticosteroids, the patient went into ileus and was transferred to the Department of Surgery, where he underwent an emergency right-sided hemicolectomy with resection of the transversal colon and forming of an ileostoma. The first pathohistological diagnosis was pseudomembranous colitis. Because the patient's condition was deteriorating, a revision of the pathohistological diagnosis was done. After careful revision and extensive sampling, a signet ring cell carcinoma arising in the appendix with infiltration of the ileocecal region was found. Immunohistochemically, tumor cells were positive for CDX-2 CK7, CK20, CK19, and carcinoembryonic antigen and negative for chromogranin A. Sixteen isolated lymph nodes were negative. Although the patient had a disease that was localized to the appendix and ileocecal region with no apparent distal metastasis, his clinical condition was worsening rapidly and he died after 2 months. This case shows the aggressive biological behavior of the appendix signet ring cell carcinoma. Scrupulous histopathological examination of the appendix is an obligatory procedure. Elimination of the signet ring cell carcinoma from other carcinoma subtypes is of special importance as it has an exceptionally poor prognosis and is generally diagnosed in its advanced stages.

Peritoneal Carcinomatosis: Feature of Dissemination a Review

Peritoneal carcinomatosis is a common event that develops in the natural history of many neoplastic diseases, representing a major problem encountered in cancer management. Peritoneal seedings are often associated with neoplastic ascites resulting in a source of significant discomfort to the patient. Considered in the past as a terminal condition, peritoneal carcinomatosis was approached during the last two decades as a curable disease. The introduction of cytoreductive surgery or peritonectomy in the treatment of peritoneal neoplastic diseases drastically changed the natural history of peritoneal carcinomatosis. Another technique that showed an important impact on disease control is intraperitoneal hyperthermic perfusion, one of the most fascinating treatments of peritoneal carcinomatosis that results in an impressive increase in overall survival and quality of life in treated patients with low morbidity. This review illustrates the modality of dissemination of peritoneal carcinomatosis in relation to the primary tumor site and grade of malignancy. Peritoneal carcinomatosis is a term used to define an advanced stage of many abdominal neoplastic diseases that differ in biologic aggressiveness and prognosis. The different presentation of peritoneal carcinomatosis in relation to a different primary tumor and different grade of malignancy strongly influences the potentially therapeutic radical approaches using new and advanced modalities like cytoreductive surgery and intraperitoneal hyperthermic perfusion.

Feasibility of Peritonectomy Associated with Intraperitoneal Hyperthermic Perfusion in Patients with Pseudomyxoma Peritonei

Aims and background

Pseudomyxoma peritonei is a rare disease characterized by a complete redistribution of mucin within the peritoneal cavity. It can be classified into three histologic groups: disseminated peritoneal adenomucinosis, peritoneal mucinous carcinomatosis, and an intermediate group. The aim of the present study was to evaluate the feasibility of cytoreductive surgery requiring peritonectomy procedures associated with intraperitoneal hyperthermic perfusion, a technique that combines hyperthermia and high drug doses administered locally.

Methods

Twenty-seven patients with pseudomyxoma peritonei (19 males and 8 females) were enrolled in a phase II clinical trial. Twenty-two cases underwent cytoreductive surgery plus intraperitoneal hyperthermic perfusion, and 6 received de-bulking surgery only. One patient was operated on twice for disease recurrence. All patients with peritoneal mucinous carcinomatosis presented serous ascites, whereas all but one patient with disseminated peritoneal adenomucinosis or in the intermediate group presented mucinous ascites. Cytoreductive surgery was performed with peritonectomy procedures. The closed abdomen technique was adopted for intraperitoneal hyperthermic perfusion using a preheated poly-saline perfusate containing cisplatin (25 mg/m2/L) plus mitomycin-C (3.3 mg/m2/L) through a heart-lung pump at a mean flow of 600 mL/min for 60 mins from the hyperthermic phase (42.5 °C).

Results

All but one of the patients with disseminated peritoneal adenomucinosis and 2 of the 3 patients in the intermediate group were optimally cytoreduced. Patients with serous ascites (all patients with peritoneal mucinous carcinomatosis and 1 patient with disseminated peritoneal adenomucinosis) were considered ineligible for treatment because of tumor diffusion. The morbidity rate was 22%. There was one case of treatment-related mortality 30 days after treatment.

Conclusions

The following conclusions can be drawn from this phase II clinical trial: 1) patients with pseudomyxoma peritonei originating from undifferentiated mucinous adenocarcinoma (peritoneal mucinous carcinomatosis), with complete distribution into the peritoneal cavity, are not eligible for the cytoreductive surgery plus intraperitoneal hyperthermic perfusion technique; 2) the presence of serous ascites would seem to exclude patients from the treatment; 3) cytoreductive surgery associated with intraperitoneal hyperthermic perfusion is the most suitable approach for patients with disseminated peritoneal adenomucinosis and in the intermediate group.

Can low grade PMP be divided into prognostically distinct subgroups based on histological features? A retrospective study and the importance of using the appropriate classification

INTRODUCTION

The pathological classification of PMP of appendiceal origin has prognostic and treatment implications. Our goals were to • Classify low grade mucinous carcinoma peritonei (LGMCP) into prognostically distinct subgroups based on histological features. • Compare the reproducibility of the WHO and the PSOGI classifications for both PMP and the appendiceal primary tumor.

PATIENTS AND METHODS

A retrospective analysis of patients undergoing CRS and HIPEC or debulking surgery was done. All the tumors were re-classified according to the PSOGI classification. LGMCP was further classified into three histological subgroups and the impact on survival was evaluated.

RESULTS

From Jun 2011 to June 2016, 101 patients underwent CRS with HIPEC (n = 89) or debulking surgery (n=12). The median PCI was 28 (3-39) and 74.1% patients had CC-0/1 resections. Of the 76.2% patients who had LGMCP, 4 patients (5.1%) were classified as group 1, 54 (70.1%) as group 2 and 19 patients (24.6%) as group 3. At a median follow up of 21 months, the disease free survival was not reached, 30 months and 14 months for groups 1, 2 and 3 respectively (p = 0.09). There was no difference in overall survival. Using the WHO classification, there was a discordance in the grade of the primary tumor and the peritoneal lesions in 19.8% and conflicting terminology was used in 62% of patients.

CONCLUSIONS

The subgroups of LGMCP described here are prognostically different though this needs further prospective evaluation in larger series. The PSOGI classification is more uniformly reproducible and should be preferred to the WHO classification.

Pseudomyxoma peritonei: natural history and treatment

Pseudomyxoma peritonei (PMP) is an uncommon disease characterised by mucinous ascites, classically originating from a ruptured low grade mucinous neoplasm of the appendix. The natural history of PMP revolves around the "redistribution phenomenon", whereby mucinous tumour cells accumulate at specific sites with relative sparing of the motile small bowel and to a lesser extent other parts of the gastrointestinal tract. Peritoneal tumour accumulates due to gravity and at the sites of peritoneal fluid absorption, namely, the greater and lesser omentum and the under-surface of the diaphragm, particularly on the right. The optimal treatment is complete macroscopic tumour excision termed cytoreductive surgery (CRS) combined with Hyperthermic Intra-Peritoneal Chemotherapy (HIPEC). Total operating time for complete CRS and HIPEC for extensive PMP is around 10 h and generally involves bilateral parietal and diaphragmatic peritonectomies, right hemicolectomy, radical greater omentectomy with splenectomy, cholecystectomy and liver capsulectomy, a pelvic peritonectomy with, or without, rectosigmoid resection and bilateral salpingo-oophorectomy with hysterectomy in females. A unique feature of low grade PMP, which differs from other peritoneal malignancies, includes slow disease progression, which may be asymptomatic until advanced stages. Additionally, very extensive disease with a high "PCI" (Peritoneal Carcinomatosis Index) may still be amenable to complete excision and cure. In cases where complete tumour removal is not feasible, maximum tumour debulking can still result in long-term survival in PMP. PMP is challenging, complex but nevertheless the most rewarding peritoneal malignancy amenable to cure by CRS and HIPEC.

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for pseudomyxoma peritonei of appendicular and extra-appendicular origin

BACKGROUND

The prognostic value of the primary neoplasm responsible for pseudomyxoma peritonei (PMP) remains poorly studied. The aim of this study was to determine the prognosis for patients with extra-appendicular PMP (EA-PMP) treated optimally with complete cytoreductive surgery (CCRS) and hyperthermic intraperitoneal chemotherapy (HIPEC).

METHODS

All patients treated for PMP with CCRS and HIPEC between 1994 and 2016 were selected retrospectively from a French multicentre database. Patients with EA-PMP had pathologically confirmed non-neoplastic appendices and were matched in a 1 : 4 ratio with patients treated for appendicular PMP (A-PMP), based on a propensity score.

RESULTS

Some 726 patients were identified, of which 61 (EA-PMP group) were matched with 244 patients (A-PMP group). The origins of primary tumours in the EA-PMP group included the ovary (45 patients), colon (4), urachus (4), small bowel (1), pancreas (1) and unknown (6). The median peritoneal carcinomatosis index was comparable in EA-PMP and A-PMP groups (15·5 versus 18 respectively; P = 0·315). In-hospital mortality (3 versus 2·9 per cent; P = 1·000) and major morbidity 26 versus 25·0 per cent; P = 0·869) were also similar between the two groups. Median follow-up was 66·9 months. The 5-year overall survival rate was 87·8 (95 per cent c.i. 83·2 to 92·5) per cent in the A-PMP group and 87 (77 to 96) per cent in the EA-PMP group. The 5-year disease-free survival rate was 66·0 (58·7 to 73·4) per cent and 70 (53 to 83) per cent respectively.

CONCLUSION

Overall and disease-free survival following treatment with CCRS and HIPEC is similar in patients with pseudomyxoma peritonei of appendicular or extra-appendicular origin.

Pseudomyxoma Peritonei Treated with Cytoreductive Surgery and Hyperthermic Chemotherapy: A 7-Year Single-Center Experience

Aims and background

Pseudomyxoma peritonei (PMP) is a rare clinical entity characterized by diffuse intraabdominal gelatinous collections with mucinous implants on the peritoneal surfaces and omentum. This condition should be considered a borderline malignancy with disease progression over time. Encouraging treatment results have been recently reported with the combination of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC).

Methods

From December 2003 to December 2010, 18 patients with PMP were referred to our institution. All patients underwent peritonectomy and CRS combined with HIPEC in accordance with Sugarbaker's procedure.

Results

The mean Peritoneal Cancer Index score was 27.6 (range, 5–39). Twelve (67%) patients had disseminated peritoneal adenomucinosis and 6 (33%) peritoneal mucinous carcinomatosis. Optimal cytoreduction with no visible residual disease or residual disease ≤2.5 mm in diameter was achieved in all patients. The mean duration of the surgical procedure including HIPEC was 9 hours and 30 minutes (range, 5–13 hours); major morbidity occurred in 30% of patients and the mortality was 11%. The mean follow-up was 27 months (range, 1–72) and the 5-year overall survival 66%.

Conclusions

In line with the existing literature, our experience suggests that patients with PMP could benefit from CRS + HIPEC in terms of survival and locoregional disease control.

Tailgut Cyst, an Unusual Cause of Pseudomyxoma Peritonei

Background

Retrorectal hamartoma, also known as tailgut cyst, is a rare tumor that arises from remnants of the embryonic postanal gut. The tumor occurs in the retrorectal space and may undergo malignant degeneration.

Methods

The clinical information on a single patient with pseudomyxoma peritonei associated with a tailgut cyst was reviewed and a literature review of the subject performed.

Results

In this patient there was malignant degeneration of a tailgut cyst localized to the pelvis. Twenty months later a local recurrence in the pelvis and pseudomyxoma peritonei widely distributed in the abdomen were successfully treated by cytoreductive surgery and perioperative chemotherapy.

Conclusion

Tailgut cyst may, if resected with tumor spillage, result in pseudomyxoma peritonei. Our treatment – which has maintained a disease-free status for one year – was cytoreductive surgery plus perioperative chemotherapy.

Mesenteric Cyst: Report of a Case Resulting in Pseudomyxoma Peritonei

Background

A mesenteric cyst may have an embryonic, traumatic, neoplastic or infectious origin. In rare cases mesenteric cysts may contain neoplastic epithelium. A mesenteric cyst has not previously been recorded as the cause of pseudomyxoma peritonei.

Methods

A patient who developed widespread mucinous intraperitoneal tumor as a result of a ruptured mesenteric cyst is reported. A literature review of the clinical features, diagnosis, treatment, and prognosis of the mesenteric cyst is presented.

Results

This patient was treated with cytoreductive surgery and perioperative intraperitoneal chemotherapy. Her recovery was uneventful and she remains well two years after treatment.

Conclusion

Mesenteric cyst is a rare cause of pseudomyxoma peritonei. The definite treatment of a ruptured neoplastic mesenteric cyst can, by analogy, be compared to the treatment for pseudomyxoma peritonei of appendiceal origin. The results of cytoreductive surgery with perioperative intraperitoneal chemotherapy are expected to be good.

An Update on the Diagnosis, Grading, and Staging of Appendiceal Mucinous Neoplasms

Despite advances in our understanding of appendiceal mucinous neoplasms and their relationship to the pseudomyxoma peritonei syndrome, the classification of mucinous tumors of the appendix is still confusing. This review will provide an update on the various classification systems that have been recently proposed for appendiceal mucinous neoplasia, with a particular emphasis on how to handle and report the histologic findings for these tumors using the newly published Peritoneal Surface Oncology Group International (PSOGI) and American Joint Committee on Cancer (AJCC) eighth edition guidelines. A simplified approach to diagnostic reporting of appendiceal mucinous neoplasms based on the 3-tier AJCC grading scheme is detailed and specific criteria for assessing grade in appendiceal mucinous neoplasia will be outlined. In addition, histologic mimics of appendiceal mucinous neoplasia and how to distinguish these mimics from mucinous neoplasia will be discussed. Finally, despite improvements in diagnostic terminology, significant challenges in classifying appendiceal mucinous neoplasia persist and diagnostic strategies will be detailed to assist practicing pathologists in these challenging scenarios.

Mucinous epithelial ovarian carcinoma

Mucinous tumours involving the ovary may be benign, borderline, or malignant. Malignant tumours may be primary or metastatic. Differentiation between primary and metastatic involvement of the ovary is critical for optimal patient management. Even among skilled pathologists, this distinction can be problematic, as can the distinction between borderline ovarian tumour of intestinal type and well-differentiated invasive primary mucinous ovarian carcinoma. Primary invasive mucinous ovarian carcinoma and mucinous carcinoma metastatic to the ovary do have distinct patterns of macroscopic and microscopic involvement which will reveal the correct diagnosis in many cases. There are also well-recognized patterns of immunohistochemical staining that can further assist in this differentiation. As a result of the application of these histopathological techniques, the incidence of primary invasive mucinous epithelial carcinoma has fallen over recent years from ∼12% to ∼3%. However, even in recent multicentre clinical trials such as GOG 182, expert pathological review suggests that ∼60% of tumours originally classified as primary invasive mucinous carcinomas were in fact metastatic tumours to the ovary. Review of outcome data for patients with mucinous carcinoma entered into multicentre trials suggests that this subtype of disease has a particularly poor prognosis in comparison with other subtypes of ovarian carcinoma. Historically, patients with mucinous epithelial ovarian carcinoma (mEOC) have been treated in the same way as other subtypes of ovarian carcinoma. While there is undoubtedly a response rate to platinum-based chemotherapy, retrospective reviews of individual centre experience suggest that this is substantially lower than for high-grade papillary serous carcinoma and in the order of only 30%-40%. The mEOC trial was established to investigate the possibility that the combination of capecitabine and oxaliplatin (chemotherapy drugs more commonly used in colorectal carcinoma) may be superior to conventional carboplatin and paclitaxel chemotherapy. In a 2 × 2 factorial design, there was also a randomization to bevacizumab. Unfortunately, this trial closed early, 5 years after initiation having recruited just 50 of a proposed 322 patients. mEOC is now characterized as a type I tumour with an identifiable stepwise progression from a premalignant lesion, through non-invasive, to invasive malignancy. Molecular characterization of mEOC reveals it to be distinct from other subtypes of the disease with a KRAS mutation occurring in 40%-50% of patients. Other gene abnormalities including HER2 amplification in ∼19% also occur. This raises the possibility of the use of targeted molecular therapies which with molecular analysis of individual patient tumours could form the basis of a future clinical trial. It is, however, clear that if trials are to be conducted in this rare subtype of disease, they will need to be truly international in nature and carefully designed, possibly using an adaptive stepwise approach and will require an appropriate level of funding with a realistic assessment of likely recruitment. Associated translational research will clearly be essential.

Incidence and Survival of Appendiceal Mucinous Neoplasms: A SEER Analysis

OBJECTIVES

The aim of this study is to characterize the changes in the incidence, presentation, surgical treatment, and survival of patients with appendiceal mucinous neoplasm (AMN) over the past 4 decades using nationwide cancer surveillance data.

METHODS

Patients with the diagnosis of AMN were identified in the Surveillance Epidemiology and End Results (SEER) database. Information on demographics, disease characteristics, and surgical treatment was collected. Temporal changes in AMN incidence, characteristics of cases, and survival were analyzed from 1973 to 2011. Determinants of overall survival (OS) were examined using both crude and multivariable Cox proportional hazard models.

RESULTS

The overall incidence rate of AMN increased on average 3.1%/1,000,000 persons-years (P<0.001). A significant decline in the age at diagnosis was observed (P=0.014). The proportion of patients presenting with distant disease at diagnosis also significantly increased (P=0.004). Five-year survival of patients with distant stage AMN increased at a rate of 3.5%/y between 1984 and 2006 (P<0.001). Median OS was not reached for localized and regional stage disease. Median OS for distant stage disease was 42 months.

CONCLUSIONS

There has been an increase in the overall incidence of AMN with an observed increase in the proportion of younger age and distant stage at diagnosis. The OS has improved over time.

Validation of the Recent PSOGI Pathological Classification of Pseudomyxoma Peritonei in a Single-Center Series of 265 Patients Treated by Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy

BACKGROUND

Controversies still persist regarding the terminology and pathologic classification of appendiceal mucinous neoplasms and associated pseudomyxoma peritonei (PMP). We assessed reproducibility and prognostic significance of the classification recently proposed by the Peritoneal Surface Oncology Group International (PSOGI).

METHODS

A prospective database of 265 PMP patients uniformly treated by cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) from 1995 to 2017 was reviewed. According to the PSOGI, peritoneal disease was retrospectively classified into three categories: low-grade (LG-PMP), high-grade (HG-PMP), and signet-ring cells (SRC-PMP). Acellular mucin (AC) was classified separately. The extent of peritoneal involvement was quantified by the peritoneal cancer index (PCI).

RESULTS

Twenty-six patients were diagnosed with AC (9.8%), 197 with LG-PMP (74.4%), 38 with HG-PMP (14.3%), and 4 with SRC-PMP (1.5%). In the overall series, median follow-up was 65.5 months (95% confidence interval 53.7-78.8) and 10-year overall survival was 62.9% (median 148.7 months). Operative death occurred in 10 patients (3.8%) and major complications occurred in 89 patients (33.6%). Ten-year survival was 89.6% for AC, 63.2% for LG-PMP, 40.1% for HG-PMP, and 0 for SRC-PMP. In a multivariate model, the World Health Organization (WHO) pathological classification independently correlated with survival (p = 0.028). In a separate model, the PSOGI classification did not reach statistical significance (p = 0.149). Completeness of cytoreduction and PCI > 22 correlated with prognosis in both models.

CONCLUSIONS

AC and SRC-PMP pathological categories of the PSOGI classification identified two subsets of patients with favorable and exceedingly dismal prognosis, respectively. It remains unclear whether the PSOGI classification might provide better prognostic stratification than the current WHO classification. Further studies in larger prospective series are needed.

Clinical studies in CRS and HIPEC: Trials, tribulations, and future directions-A systematic review

BACKGROUND

The field of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) has suffered from a lack of clinical trials to validate its expanding use.

OBJECTIVE

To evaluate published and ongoing clinical trials seeking to better define role of CRS/HIPEC in the treatment of peritoneal surface malignancies.

METHODS

Systematic review by PubMed search was performed using terms "Clinical trial," "intraperitoneal chemotherapy," and "HIPEC." ClinicalTrials.gov and EudraCT registries were searched for active clinical trials. Eligibility included CRS/HIPEC trials investigating adult patient populations from published clinical reports and/or trials currently accruing or at completion.

RESULTS

Thirteen published trials and 57 active clinical trials were included for review.

CONCLUSIONS

Published and ongoing U.S. and international clinical trials for CRS and HIPEC are defining important parameters that include improving patient selection, strategic sequences of treatment, cytoreductive strategies, chemotherapeutics, optimal hyperthermic temperature and timing, and toxicity profiles. Main barriers or limitations to trial development remain patient enrollment, trial design, and oncologic community collaboration. Overall progress is positive with increasing number of clinical trials throughout the world. Collaboration between surgeons and the wider oncologic community will be crucial to validate this important treatment strategy.

Impact of Cellularity on Oncologic Outcomes Following Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemoperfusion for Pseudomyxoma Peritonei

BACKGROUND

The Peritoneal Surface Oncology Group International (PSOGI) recommends pathologic reporting of tumor cellularity in patients with pseudomyxoma peritonei (PMP) undergoing cytoreductive surgery and hyperthermic intraperitoneal chemoperfusion (CRS-HIPEC). We investigated the prognostic significance of PMP cellularity, or lack thereof (acellular mucin), following CRS-HIPEC.

METHODS

We reviewed clinical data for 310 CRS-HIPEC procedures in low-grade (American Joint Committee on Cancer grade G1) PMP with acellular mucin (n = 19), scant cellularity (n = 30), or moderate cellularity (n = 242). Kaplan-Meier survival curves and multivariate Cox regression models identified prognostic factors affecting oncologic outcomes.

RESULTS

Compared with patients with acellular mucin, those with scant and moderate cellularity had higher PCI and less-frequent complete macroscopic resection. After an estimated median follow-up of 49 months, 4 patients (14%) with scant cellularity and 127 patients (56%) with moderate cellularity progressed, while none of the patients with acellular mucin progressed. While the median progression-free survival (PFS) was not reached for patients with acellular mucin or scant cellularity (estimated 5-year PFS probability of 100 and 83%, respectively), patients with moderate cellularity demonstrated a median PFS of 32 months (estimated 5-year PFS probability of 27%). In a multivariate model, degree of disease cellularity, or lack thereof (acellular mucin), was an independent predictor of PFS but not overall survival.

CONCLUSIONS

Early disease progression is unlikely in patients with acellular mucin undergoing CRS-HIPEC, as opposed to a 14% recurrence rate with scant cellularity. Thorough pathologic assessment for cellularity, or lack thereof (acellular mucin), is vital for accurate prognostication of disease progression for patients with low-grade PMP undergoing CRS-HIPEC.

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in the management of pseudomyxoma peritonei: A single-center experience

BACKGROUND AND AIMS

Pseudomyxoma peritonei (PMP) results from perforated appendiceal tumors. It is usually diagnosed preoperatively by imaging. Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC), although aggressive long procedure with high complications rate, was considered the optimal treatment. This study is aiming to study the role of CRS and HIPEC in the management of PMP and assess the outcome.

METHODS

This is a retrospective study which was conducted at King Faisal Hospital and Research Center, a tertiary care hospital during the period from November 2008 to June 2016. Approval of the Research Advisory Council was obtained. Forty-one procedures of CRS and HIPEC were performed in 38 patients. Using the open abdomen technique, CRS was performed using standard peritonectomy procedures and visceral resections directed toward the complete elimination of tumors from abdominopelvic cavity. HIPEC was performed using mitomycin C in a dose of 30 mg/m2 and allowed to circulate in abdominopelvic cavity for 90 min at 41.0 to 42.2 °C.

RESULTS

Forty-one procedures were performed in 38 patients. Three procedures were done as repeat CRS and HIPEC. No perioperative mortality. Cystoscopy and bilateral ureteric stents in 35 procedures (85.5%). Hospital stay (range 9-85 days) average is 21 days. Follow up period is 1-84 months, and median follow up is 54 months. Five-year survival rate is 92%. Median 5-year disease-free survival rate is 60%. Two patients died during the follow up period by septic shock and one patient died from disease progression.

CONCLUSION

CRS and HIPEC is well-tolerated and feasible management for PMP.

Grading and staging mucinous neoplasms of the appendix: a case series and review of the literature

The grading and staging of appendiceal mucinous neoplasms is challenging and fraught with terminology problems, but has critical prognostic and therapeutic implications. We utilized a small case series to examine the grading and staging systems of appendiceal mucinous neoplasms and outline the evidence for the new systems proposed in the upcoming 8th edition of the American Joint Committee on Cancer (AJCC) Staging Manual. We reviewed 33 cases of appendiceal mucinous neoplasms with available clinical follow-up data, 6 of which were widely disseminated in the peritoneum. An additional 4 cases with disseminated peritoneal involvement were also reviewed. A detailed review of the literature was performed with an emphasis on features associated with disease recurrence and correlation of grade with outcome. Recurrence was not seen in 64 low-grade appendiceal mucinous neoplasms (LAMNs) confined to the muscularis propria in our series (n=21) or in the literature (n=43). Of cases of LAMN with neoplastic epithelium present beyond the muscularis propria, 64% (57/89) had peritoneal disease at the time of diagnosis or follow-up. A majority of studies of disseminated appendiceal mucinous neoplasms showed significant five-year survival differences using a three-tier grading scheme. Thus, LAMNs confined to the muscularis propria are best considered as in situ tumors, as these are cured with complete excision. A three-tier system has prognostic significance and should be used for grading of disseminated appendiceal mucinous neoplasms. The conclusions of this case series and literature review provide evidence to support the changes proposed in the 8th edition of the AJCC Staging Manual.