Predicting Survival in Mucinous Adenocarcinoma of the Appendix: Demographics, Disease Presentation, and Treatment Methodology.

BACKGROUND: Mucinous adenocarcinoma of the appendix (MACA) follows a complex disease course with variable survival. Large-scale predictive modeling may determine subtle yet important prognostic factors otherwise unseen in smaller cohort analyses. METHODS: Patients with MACA were identified from the Surveillance, Epidemiology, and End Results (SEER) Research Plus database (2005-2019). Primary, secondary, and tertiary outcomes were disease-specific survival (DSS), overall survival (OS), and average annual percent change (AAPC) in incidence. RESULTS: Among 4,258 included patients, MACA was most frequently diagnosed at 50 to 69 years (52.0%), with female preponderance (55.9%). MACA incidence AAPC was 3.8 (95% confidence interval [CI] 1.9-5.9). For patients with exclusive, first-diagnosis MACA included in survival analysis (3,222 patients), median DSS and OS were 118 and 88 months, respectively. In DSS-based multivariable analysis, worse prognosis was associated with non-Hispanic Black background (HR 1.36, 95% CI 1.02-1.82; p = 0.036), high grade (grade 3 HR 3.10, 95% CI 2.44-3.92; p < 0.001), lymphatic spread (HR 2.73, 95% CI 2.26-3.30; p < 0.001), and distant metastasis (HR 5.84, 95% CI 3.86-8.83; p < 0.001). In subcohort analysis of patients with rationale for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC, 2,387 patients), CRS-HIPEC was associated with survival benefit compared with surgery alone but only for moderate-grade tumors (median DSS/OS 138/138 vs. 116/87 months; p < 0.001). CONCLUSIONS: Mucinous adenocarcinoma of the appendix incidence is increasing in the United States. Survival rates are affected by both demographics and classical risk factors, and CRS-HIPEC-associated survival benefit predominantly occurs in moderate-grade tumors. Further exploration of biologic and clinicopathologic features may enhance risk stratification for this disease.

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

BACKGROUND: Mucinous appendiceal adenocarcinomas (MAA) and non-mucinous appendiceal adenocarcinomas (NMAA) demonstrate differences in rates and patterns of recurrence, which may inform the appropriate extent of surgical resection (i.e., appendectomy versus colectomy). The impact of extent of resection on disease-specific survival (DSS) for each histologic subtype was assessed. PATIENTS AND METHODS: Patients with resected, non-metastatic MAA and NMAA were identified in the Surveillance, Epidemiology, and End Results database (2000-2020). Multivariable models were created to examine predictors of colectomy for each histologic subtype. DSS was calculated using Kaplan-Meier estimates and examined using Cox proportional hazards modeling. RESULTS: Among 4674 patients (MAA: n = 1990, 42.6%; NMAA: n = 2684, 57.4%), the majority (67.8%) underwent colectomy. Among colectomy patients, the rate of nodal positivity increased with higher T-stage (MAA: T1: 4.6%, T2: 4.0%, T3: 17.1%, T4: 21.6%, p < 0.001; NMAA: T1: 6.8%, T2: 11.4%, T3: 25.6%, T4: 43.8%, p < 0.001) and higher tumor grade (MAA: well differentiated: 7.7%, moderately differentiated: 19.2%, and poorly differentiated: 31.3%; NMAA: well differentiated: 9.0%, moderately differentiated: 20.5%, and 44.4%; p < 0.001). Nodal positivity was more frequently observed in NMAA (27.6% versus 16.4%, p < 0.001). Utilization of colectomy was associated with improved DSS for NMAA patients with T2 (log rank p = 0.095) and T3 (log rank p = 0.018) tumors as well as moderately differentiated histology (log rank p = 0.006). Utilization of colectomy was not associated with improved DSS for MAA patients, which was confirmed in a multivariable model for T-stage, grade, and use of adjuvant chemotherapy [hazard ratio (HR) 1.00, 95% confidence interval (CI) 0.81-1.22]. CONCLUSIONS: Colectomy was associated with improved DSS for patients with NMAA but not MAA. Colectomy for MAA may not be required.

Comparison of EPIC Versus HIPEC in the Treatment of Colorectal Peritoneal Metastases and Appendix Tumors Using Inverse Probability of Treatment Weighting.

BACKGROUND: The selection of hyperthermic intraperitoneal chemotherapy (HIPEC) or early postoperative intraperitoneal chemotherapy (EPIC) for peritoneal metastases from colorectal cancer or appendiceal neoplasms following cytoreductive surgery (CRS) depends on the surgeon's discretion. This study was designed to compare postoperative and oncologic outcomes of HIPEC and EPIC using inverse probability of treatment weighting (IPTW). METHODS: This study included 175 patients who received HIPEC or EPIC following CRS at a single tertiary university hospital between December 1999 and December 2020. Inverse probability of treatment weighting analysis was performed to control for pretreatment characteristics between the two groups. Multivariate analysis was performed to determine factors associated with postoperative and survival outcomes. RESULTS: After IPTW, no significant differences in baseline demographics and tumor characteristics were observed between the two groups. The HIPEC group had a significantly longer operation time than the EPIC group. The EPIC group showed a significantly higher postoperative mortality rate than the HIPEC group. Operation time (odds ratio [OR] 1.01; 95% confidence interval [CI] 1.01-1.02; p < 0.001), bowel anastomosis (OR 7.25; 95% CI 1.16-45.2; p = 0.034), neoadjuvant chemotherapy (OR 7.62; 95% CI 1.85-31.4; p = 0.005), and EPIC (OR 8.76; 95% CI 2.16-35.5; p = 0.002) were independent risk factors for major surgical complications. No association was observed between intraperitoneal chemotherapy type and major hematologic toxicity, overall survival, progression-free survival, or peritoneal progression-free survival. CONCLUSIONS: EPIC was a risk factor for major surgical complications. Survival outcomes were similar between the two types of intraperitoneal chemotherapy.

Impact of PIPAC-Oxaliplatin on Functional Recovery, Good Days, and Survival in a Refractory Colorectal and Appendiceal Carcinomatosis: Secondary Analysis of the US PIPAC Collaborative Phase 1 Trial.

BACKGROUND: Pressurized intraperitoneal aerosolized chemotherapy (PIPAC) is a novel, minimally invasive, safe, and repeatable method to treat carcinomatosis. Evidence regarding the clinical benefit (quality of life and survival) of PIPAC compared with that of conventional standard therapy (ST) is lacking. METHODS: This is the secondary analysis of the phase 1 US-PIPAC trial for refractory colorectal and appendiceal carcinomatosis. A PIPAC cohort was compared with a retrospective cohort of consecutive patients receiving ST. The primary outcome was number of good days (number of days alive and out of the hospital). The secondary outcomes were overall survival (OS), progression-free survival (PFS), health-related quality of life (HRQoL), and objective functional recovery (daily step count). RESULTS: The study included 32 patients (PIPAC, 12; ST, 20) with similar baseline characteristics. Compared with the ST cohort, the PIPAC cohort had lower median inpatient hospital stays (> 24 h) within 6 months (0 vs 1; p = 0.015) and 1 year (1 vs 2; p = 0.052) and higher median good days at 6 months (181 vs 131 days; p = 0.042) and 1 year (323 vs 131 days; p = 0.032). There was no worsening of HRQoL after repeated PIPACs. Step counts diminished immediately after PIPAC but returned to baseline within 2-4 weeks. Kaplan-Meier analysis demonstrated a favorable association between receipt of PIPAC and OS (median, 11.3 vs 5.1 months; p = 0.036). CONCLUSION: Compared with ST, PIPAC was associated with higher number of good days, reduced hospitalization burden, and longer OS without a negative impact on HRQoL with repeated PIPACs. These findings are foundational for evaluation of PIPAC in a randomized clinical trial.

Critical reappraisal of prognostic indicators for 949 mucinous appendiceal neoplasm patients.

BACKGROUND AND OBJECTIVES: The standard of care for treatment of an appendiceal mucinous neoplasm with peritoneal dissemination is cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC). These two treatments are combined in the operating room. A crucial requirement for benefit long-term is proper patient selection. Clinical and histopathologic prognostic indicators are used, along with the patient's fitness for surgery, to select patients to receive CRS and HIPEC. METHODS: This study seeks to identify the reliable prognostic indicators for four different groups of patients. They are (1) the low-grade appendiceal mucinous neoplasms (LAMN) with a complete CRS, (2) the mucinous appendiceal adenocarcinomas (MACA) with complete CRS, (3) MACA with lymph node metastases (MACA-LN) with complete CRS, and (4) all histologic subtypes with incomplete cytoreduction. The prognostic indicators were evaluated for their impact on overall survival in these four groups of patients. RESULTS: The completeness of cytoreduction (CC) score statistically significantly showed survival differences in all three histologic subtypes. The peritoneal cancer index (PCI) showed significance with LAMN and MACA-LN but not with MACA and not with incomplete CRS. The prior surgical score (PSS) was a prognostic indicator that predicted the outcome with LAMN, MACA-LN, and incomplete CRS patients but not with the MACA group. Patients who were symptomatic or who had extensive systemic chemotherapy before CRS had a significantly reduced survival. CONCLUSION: The utility of prognostic indicators varied greatly within our four different groups of appendiceal mucinous neoplasms. CC score was always a reliable prognosticator. Surprisingly, PCI was not.

Long term survival outcomes of surgery combined with hyperthermic intraperitoneal chemotherapy for perforated low-grade appendiceal mucinous neoplasms: A multicenter retrospective study.

BACKGROUND: Low-grade appendiceal mucinous neoplasms (LAMN) are very rare, accounting for approximately 0.2%-0.5% of gastrointestinal tumors. We conducted a multicenter retrospective study to explore the impact of different surgical procedures combined with HIPEC on the short-term outcomes and long-term survival of patients. METHODS: We retrospectively analyzed the clinicopathological data of 91 LAMN perforation patients from 9 teaching hospitals over a 10-year period, and divided them into HIPEC group and non-HIPEC group based on whether or not underwent HIPEC. RESULTS: Of the 91 patients with LAMN, 52 were in the HIPEC group and 39 in the non-HIPEC group. The Kaplan-Meier method predicted that 52 patients in the HIPEC group had 5- and 10-year overall survival rates of 82.7% and 76.9%, respectively, compared with predicted survival rates of 51.3% and 46.2% for the 39 patients in the non-HIPEC group, with a statistically significant difference between the two groups (χ2 = 10.622, p = 0.001; χ2 = 10.995, p = 0.001). Compared to the 5-year and 10-year relapse-free survival rates of 75.0% and 65.4% in the HIPEC group, respectively, the 5-year and 10-year relapse-free survival rates of 48.7% and 46.2% in the non-HIPEC group were significant different between the two outcomes (χ2 = 8.063, p = 0.005; χ2 = 6.775, p = 0.009). The incidence of postoperative electrolyte disturbances and hypoalbuminemia was significantly higher in the HIPEC group than in the non-HIPEC group (p = 0.023; p = 0.044). CONCLUSIONS: This study shows that surgery combined with HIPEC can significantly improve 5-year and 10-year overall survival rates and relapse-free survival rates of LAMN perforation patients, without affecting their short-term clinical outcomes.

Analysis of causes and prognostic impact of tube occlusion during hyperthermic intraperitoneal chemotherapy for appendiceal pseudomyxoma peritonei.

BACKGROUND: Appendiceal pseudomyxoma peritonei (PMP), a rare tumor from mucinous appendiceal origins, is treated with Cytoreductive Surgery (CRS) and Hyperthermic Intraperitoneal Chemotherapy (HIPEC). However, tubing blockages during HIPEC treatment pose a common challenge, impeding the smooth progression of therapy. Few studies to date have explored the incidence and risk factors of tube occlusion during HIPEC in patients with appendiceal PMP, as well as its adverse impact on postoperative complications. METHODS: From October 2017 to June 2023, a total of 80 patients with appendiceal PMP undergoing combined CRS and HIPEC were included in this study. Tubing blockage events were strictly defined, with patients experiencing blockages during HIPEC treatment allocated to the study group, while those with unobstructed perfusion were assigned to the control group. A comparative analysis was conducted between the two groups regarding post-HIPEC health assessments and occurrence of complications. Risk factors for luminal occlusion during closed HIPEC procedures were identified through univariate and multivariate analysis of data from 303 HIPEC treatments. RESULTS: Tubing blockages occurred in 41 patients (51.3%). The study group experienced prolonged gastrointestinal decompression time (4.1 ± 3.0 vs. 2.5 ± 1.7 days, P = 0.003) and prolonged time to bowel movement (6.1 ± 2.3 vs. 5.1 ± 1.8 days, P = 0.022) compared to the control group. There was no significant difference in the incidence of complications between the two groups. The 1-year survival rate postoperatively was 97%, and the 3-year survival rate was 81%, with no association found between tubing blockage and poorer survival. Additionally, In 303 instances of HIPEC treatment among these 80 patients, tube occlusion occurred in 89 cases (89/303, 29.4%). Multivariable logistic regression analysis revealed age, diabetes, hypertension, and pathology as independent risk factors for tube occlusion. CONCLUSION: Tubing blockages are a common occurrence during HIPEC treatment, leading to prolonged postoperative gastrointestinal functional recovery time. When patients are elderly and have concomitant hypertension and diabetes, along with a histological type of low-grade mucinous tumor, the risk of tube occlusion increases. However, this study did not find a significant correlation between tubing blockage and the incidence of postoperative complications or overall patient survival.

Nomogram to predict overall survival of patients with pseudomyxoma peritonei of appendiceal origin: A retrospective cohort study.

BACKGROUND: Pseudomyxoma peritonei (PMP) is a rare disease, with the rate of overall survival (OS) influenced by many factors. The present study aimed to define independent predictors and establish a nomogram for individual risk prediction in PMP patients. METHODS: One hundred forty-seven PMP patients were consecutively included between June 1, 2013, and November 22, 2019. The log-rank test was used to compare the OS rate between groups; subsequently, variables with p < .10 were subjected to multivariate Cox modeling for defining independent prediction indicators. Finally, a nomogram was established based on independent prognosticators and assessed for internal validation. RESULTS: Multivariate Cox analysis showed that D-dimer level, carbohydrate antigen (CA) 125 level, CA 19-9 level, degree of radical surgery, and histological grade were all independently associated with OS in PMP patients. A nomogram was plotted and underwent internal validation. The discrimination ability of the nomogram revealed a good predictive ability as indicated by the C-index value (0.825), and calibration plots confirmed good consistency between the predicted and observed survival probabilities. CONCLUSIONS: Five independent prognostic factors for predicting the survival of PMP patients were identified, and the nomogram based on these independent indicators showed a reasonable discrimination ability for individual risk prediction.

Lymph node positivity and association with long-term survival for different histologies of appendiceal cancer.

BACKGROUND: Appendiceal cancers represent a diverse group of malignancies with varying biological behavior. The significance of lymph node metastases in relation to long-term survival and chemotherapy response is poorly defined. METHODS: The National Cancer Database was queried to find patients diagnosed with appendiceal cancer from 1998 to 2012. Kaplan-Meier curves and multivariable Cox regression analyses were used to study the association between lymph node status and overall survival. Stage IV patients were excluded. RESULTS: The rate of nodal positivity of the 9841 patients with known node status was: signet ring 47.4%, carcinoid 42.3%, nonmucinous adenocarcinoma 28.8%, goblet cell 21.9%, and mucinous adenocarcinoma 20.4%. Node-positive patients had worse long-term survival for all subtypes with the exception of carcinoid tumors (p < 0.001). The strongest association was for signet cell and goblet cell. Adjuvant chemotherapy in node-positive patients improved survival for mucinous, nonmucinous, and signet ring cell histology (p < 0.01), but not for goblet cell. CONCLUSIONS: Nodal involvement in patients with appendiceal cancer varies in incidence, association with adverse survival, and response to systemic therapy. Individualized treatment algorithms for the management of the subtypes of appendiceal cancer are needed.

Clinicopathological Characteristics of Low-Grade Appendiceal Mucinous Neoplasm.

INTRODUCTION: Recently, "low-grade appendiceal mucinous neoplasms" (LAMNs) have been proposed as one subtype of appendiceal mucinous neoplasms, characterized by a villous or flat proliferation of mucinous epithelium with low-grade cytologic atypia. The aim of this study was to clarify the clinicopathological characteristics of LAMN. METHODS: In this multi-institutional cohort study, we retrospectively analyzed the clinicopathological characteristics in appendiceal neoplasms patients who underwent treatment from 2000 to 2017. RESULTS: In total, 922 patients were enrolled, with 279 (30.3%) cases of LAMN, and 93 (10.1%) cases of non-LAMN disease. In comparison with patients with non-LAMN disease, those with LAMN had significantly lower levels of CA19-9 (p = 0.045), a lower frequency of T4 tumors (p < 0.0001), a lower frequency of lymph node metastasis (p < 0.0001), and a lower frequency of distant metastasis (p < 0.0001). Survival analysis revealed that patients with LAMN had a significantly better prognosis than did those with non-LAMN disease (p < 0.001). Among the patients with distant metastasis, those with LAMN had a significantly better prognosis than did those with non-LAMN disease (p = 0.0020), but among the patients without distant metastasis, the difference between the 2 groups was not significant (p = 0.26). However, among patients who underwent complete resection, the difference in prognosis between the 2 groups was not significant (p = 0.10). CONCLUSIONS: A multicenter retrospective study revealed that the clinicopathological characteristics of LAMN was different from those of non-LAMN.

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.

Preoperative Risk Score for Predicting Incomplete Cytoreduction: A 12-Institution Study from the US HIPEC Collaborative.

BACKGROUND: For patients with peritoneal carcinomatosis undergoing cytoreductive surgery with heated intraperitoneal chemotherapy (CRS/HIPEC), incomplete cytoreduction (CCR2/3) confers morbidity without survival benefit. The aim of this study is to identify preoperative factors which predict CCR2/3. METHODS: All patients who underwent curative-intent CRS/HIPEC of low/high-grade appendiceal, colorectal, or peritoneal mesothelioma cancers in the 12-institution US HIPEC Collaborative from 2000 to 2017 were included (n = 2027). The primary aim is to create an incomplete-cytoreduction risk score (ICRS) to predict CCR2/3 CRS utilizing preoperative data. ICRS was created from a randomly selected cohort of 50% of patients (derivation cohort) and verified on the remaining patients (validation cohort). RESULTS: Within our derivation cohort (n = 998), histology was low-grade appendiceal neoplasms in 30%, high-grade appendiceal tumor in 41%, colorectal tumor in 22%, and peritoneal mesothelioma in 8%. CCR0/1 was achieved in 816 patients and CCR 2/3 in 116 patients. On multivariable analysis, preoperative factors associated with incomplete cytoreduction were male gender [odds ratio (OR) 3.4, p = 0.007], presence of ascites (OR 2.8, p = 0.028), cancer antigen (CA)-125 ≥ 40 U/mL (OR 3.4, p = 0.012), and carcinoembryonic antigen (CEA) ≥ 4.2 ng/mL (OR 3.2, p = 0.029). Each preoperative factor was assigned a score of 0 or 1 to form an ICRS from 0 to 4. Scores were grouped as zero (0), low (1-2), or high (3-4). Incidence of CCR2/3 progressively increased by risk group from 1.6% in zero to 13% in low and 39% in high. When ICRS was applied to the validation cohort (n = 1029), this relationship was maintained. CONCLUSION: The incomplete cytoreduction risk score incorporates preoperative factors to accurately stratify the risk of CCR2/3 resection in CRS/HIPEC. This score should not be used in isolation, however, to exclude patients from surgery.

Improved Survival with Experience: A 10-Year Learning Curve in Hyperthermic Intraperitoneal Chemotherapy and Cytoreductive Surgery.

BACKGROUND: Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) is an aggressive locoregional treatment for peritoneal carcinomatosis (PC). Studies demonstrate improved perioperative and oncologic outcomes at high-volume centers. METHODS: This study retrospectively analyzed all patients with PC from various malignancies who underwent attempted CRS/HIPEC at the authors' institution from 2007 to 2017. Clinicopathologic, perioperative, and oncologic outcomes of early (2007-2012) and late (2012-2017) experience were compared, and multivariate analyses for factors predictive of perioperative and oncologic outcomes were performed. RESULTS: The study enrolled 388 patients (157 early and 231 late). The late experience contained more appendiceal low-grade mucinous neoplasms (LGMNs; 21% vs 9%) and had a lower Peritoneal Cancer Index (PCI; 10 vs 16). Moreover, achieving a similar rate of CC-0/1 required fewer organ resections, involved shorter operations (298 vs 347 min), and had lower estimated blood loss (EBL) (400 vs 200 ml) (p < 0.05). More procedures were aborted (20% vs 3%; p < 0.01). The late experience had fewer ICU admissions (13% vs. 55%) and a lower perioperative mortality rate (0% vs 3%) (p < 0.05). In the multivariate analyses, PCI and number of organ resections were independent predictors of multiple perioperative outcomes [EBL, operating room time, intensive care unit (ICU) admission, ICU length of stay (LOS), overall LOS]. Survival was significantly longer in the late cohort (median overall survival: NR vs 31 months; progression-free survival: 22 vs 11 months; p < 0.01), even after control for tumor histology. CONCLUSIONS: At the authors' high-volume center, with increased surgeon and institutional experience over time, perioperative and oncologic outcomes have improved significantly for patients undergoing CRS/HIPEC for PC.

Outcomes After Adjuvant Hyperthermic Intraperitoneal Chemotherapy for High-Risk Primary Appendiceal Neoplasms After Complete Resection.

INTRODUCTION: Appendiceal neoplasms are uncommon tumors. Optimal treatment for patients with perforation or high-grade pathology after initial resection is unknown. This study evaluated patients with increased risk for peritoneal dissemination after primary resection, but no evidence of peritoneal disease, who underwent adjuvant hyperthermic intraperitoneal chemotherapy (HIPEC). METHODS: This multi-institutional cohort study evaluated 56 patients with high-risk (HR) appendiceal neoplasms with a peritoneal carcinomatosis index of 0 who underwent HIPEC. The patients were divided into two groups: perforated low-grade appendiceal (LGA) carcinoma and HR neoplasms, which included perforated high-grade appendiceal carcinoma, positive margins after initial resection, minimal macroscopic peritoneal disease that was previously resected or completely responded to systemic chemotherapy prior to HIPEC, goblet cell carcinoma, and adenocarcinoma with signet ring cell features. Overall survival (OS) and recurrence-free survival (RFS) were estimated by Kaplan-Meier analysis. RESULTS: Thirty-eight percent of patients had perforated LGA and 68% had HR features. Five-year OS probability was 82.1% for the entire cohort, and 100% and 70.1% for patients with perforated LGA and HR features, respectively (p = 0.024). Five-year RFS probability was 79.3% for the entire cohort, and 90.0% and 72.4% for patients with perforated LGA and HR features, respectively (p = 0.025). Eight patients recurred after HIPEC and their OS was significantly worse (p < 0.001). CONCLUSION: While adjuvant HIPEC is both safe and feasible, there appears to be little benefit over close surveillance when outcomes are compared with historical and prospective studies, especially for perforated LGA carcinoma.

Surveillance of Low-Grade Appendiceal Mucinous Neoplasms With Peritoneal Metastases After Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy: Are 5 Years Enough? A Multisite Experience.

BACKGROUND: Low-grade appendiceal mucinous neoplasms (LAMNs) are tumors that often present with widespread mucin in the peritoneal cavity (pseudomyxoma peritonei [PMP]). Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) are effective treatment, but no published recommendations exist regarding surveillance. METHODS: Data from prospective databases of patients who underwent CRS-HIPEC from 2001 to 2017 at two high-volume institutions were retrospectively analyzed. Patients who underwent complete CRS-HIPEC for PMP secondary to LAMN were included in the analysis. Pathologic examination confirmed the diagnosis of LAMN. Cases of mucinous adenocarcinomas and neuroendocrine tumors (goblet cell carcinoids) were excluded. RESULTS: The study enrolled 156 patients. The median peritoneal cancer index (PCI) was 18 (interquartile range IQR1-3, 12-23), and 125 patients (80.1%) had a CC0 cytoreduction. According to American Joint Committee on Cancer (AJCC) grading, 152 patients (97.4%) presented with acellular mucin or G1 implants, 2 patients (1.3%) presented with G2 disease, and 2 patients (1.3%) presented with G3 disease. During the follow-up period (median, 45 months; IQR1-3 23-76 months), 23 patients (14.7%) experienced recurrence. All the recurrences were peritoneal and occurred within 5 years. The 1-, 3-, and 5-year disease-free survival (DFS) rates were respectively 95.5%, 83.4%, and 78.3%. Univariate Cox regression analysis showed that higher PCI scores (p < 0.001), a CC1 cytoreduction (p = 0.005), and higher preoperative levels of carcinoembryonic antigen (CEA) (p = 0.012) and CA-125 (p = 0.032) correlated with a shorter DFS. Only higher PCI scores independently predicted earlier recurrences (p < 0.001). CONCLUSION: Most patients had recurrence within 3 years after CRS-HIPEC, and none after 5 years. High PCI was the only independently significant variable. The study findings support intensive surveillance (every 3-6 months) with tumor markers and imaging methods during the first 3 years, and annual surveillance thereafter, with follow-up assessment after 5 years yielding limited benefit.

Optimal Surveillance Frequency After CRS/HIPEC for Appendiceal and Colorectal Neoplasms: A Multi-institutional Analysis of the US HIPEC Collaborative.

BACKGROUND: No guidelines exist for surveillance following cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) for appendiceal and colorectal cancer. The primary objective was to define the optimal surveillance frequency after CRS/HIPEC. METHODS: The U.S. HIPEC Collaborative database (2000-2017) was reviewed for patients who underwent a CCR0/1 CRS/HIPEC for appendiceal or colorectal cancer. Radiologic surveillance frequency was divided into two categories: low-frequency surveillance (LFS) at q6-12mos or high-frequency surveillance (HFS) at q2-4mos. Primary outcome was overall survival (OS). RESULTS: Among 975 patients, the median age was 55 year, 41% were male: 31% had non-invasive appendiceal (n = 301), 45% invasive appendiceal (n = 435), and 24% colorectal cancer (CRC; n = 239). With a median follow-up time of 25 mos, the median time to recurrence was 12 mos. Despite less surveillance, LFS patients had no decrease in median OS (non-invasive appendiceal: 106 vs. 65 mos, p < 0.01; invasive appendiceal: 120 vs. 73 mos, p = 0.02; colorectal cancer [CRC]: 35 vs. 30 mos, p = 0.8). LFS patients had lower median PCI scores compared with HFS (non-invasive appendiceal: 10 vs. 19; invasive appendiceal: 10 vs. 14; CRC: 8 vs. 11; all p < 0.01). However, on multivariable analysis, accounting for PCI score, LFS was still not associated with decreased OS for any histologic type (non-invasive appendiceal: hazard ratio [HR]: 0.28, p = 0.1; invasive appendiceal: HR: 0.73, p = 0.42; CRC: HR: 1.14, p = 0.59). When estimating annual incident cases of CRS/HIPEC at 375 for non-invasive appendiceal, 375 invasive appendiceal and 4410 colorectal, LFS compared with HFS for the initial two post-operative years would potentially save $13-19 M/year to the U.S. healthcare system. CONCLUSIONS: Low-frequency surveillance after CRS/HIPEC for appendiceal or colorectal cancer is not associated with decreased survival, and when considering decreased costs, may optimize resource utilization.

Outcomes in Peritoneal Carcinomatosis from Appendiceal Goblet Cell Carcinoma Treated with Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy (CRS/HIPEC).

BACKGROUND: Appendiceal goblet cell adenocarcinoma (GCA) is often misclassified and mistreated due to mixed histologic features. In general, cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) is standard of care for peritoneal carcinomatosis (PC) from mucinous appendiceal tumors; however, in PC from GCA, data are limited and the role of CRS/HIPEC is controversial. We report outcomes in PC from appendiceal GCA treated with CRS/HIPEC. PATIENTS AND METHODS: A prospective institutional database of 391 CRS/HIPEC patients with appendiceal carcinomatosis from 1998 to 2018 was reviewed. Twenty-seven patients with GCA were identified. Perioperative variables were described. Survival was estimated using the Kaplan-Meier method. RESULTS: GCA occurred in 7% (27/391) of appendiceal CRS/HIPEC patients. Seven (26%) cases were aborted. Two patients underwent a second CRS/HIPEC for peritoneal recurrence. Median age at diagnosis was 53 years (range 39-72 years), and 12 (60%) were female. All underwent previous surgery. Seven (35%) had prior chemotherapy and received a median of 5 cycles (range 3-8). Median PCI was 6 (range 1-39). Complete cytoreduction was achieved in 95% (19/20). Grade III complications occurred in three (15%) patients, and no perioperative deaths occurred. Median follow-up was 97 months. Overall survival at 1, 3 and 5 years was 100%, 74% and 67%, respectively. Progression-free survival at 1, 3, and 5 years was 94%, 67% and 59%, respectively. CONCLUSION: CRS/HIPEC should be considered as the main treatment option for patients with PC from appendiceal GCA. When performed at a CRS/HIPEC specialty center, 5-year OS of 67% can be achieved.

Prognostic Impact of BRAF and KRAS Mutation in Patients with Colorectal and Appendiceal Peritoneal Metastases Scheduled for CRS and HIPEC.

BACKGROUND: KRAS and BRAF mutations are prognostic and predictive tools in metastatic colorectal cancer, but little is known about their prognostic value in patients scheduled for cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Therefore, we analyzed the prognostic impact of KRAS and BRAF mutations in patients with peritoneal metastases scheduled for CRS and HIPEC. PATIENTS AND METHODS: In a consecutive series of 399 patients scheduled for CRS and HIPEC between 2009 and 2017, 111 subjects with peritoneal metastases from primaries of the appendix, colon, or rectum were analyzed for KRAS mutation and 92 for BRAF mutation. RESULTS: Mutation in KRAS was present in 51/111 (46%), and mutated BRAF was found in 10/92 (11%). There was no difference in overall survival between KRAS mutation tumors and KRAS wild type, whereas BRAF mutation was associated with short survival. No subject with BRAF mutation survived 2 years. On multivariate analysis, completeness of cytoreduction score (CCS, p = 0.000001), presence of signet cell differentiation (p = 0.000001), and BRAF mutation (p = 0.0021) were linked with poor prognosis. CONCLUSIONS: BRAF mutation is a marker of poor prognosis in patients with appendiceal and colorectal peritoneal metastases scheduled for CRS and HIPEC, whereas survival outcome in subjects with mutated KRAS does not differ from wild-type KRAS. This finding suggests that those with BRAF mutation should be considered for alternative treatment options.

Clinicopathological analysis of appendiceal goblet cell adenocarcinoma with peritoneal metastasis: World Health Organization grade predicts survival following cytoreductive surgery with intraperitoneal chemotherapy.

AIMS: Peritoneal spread is the most common route of metastasis in appendiceal goblet cell adenocarcinoma. The aim of this study was to assess the prognostic significance of the World Health Organization (WHO) 5th edition grading criteria in peritoneal metastases of goblet cell adenocarcinoma. METHODS AND RESULTS: We evaluated the clinicopathological features and survival of 63 patients with peritoneal metastasis of goblet cell adenocarcinoma who underwent cytoreductive surgery with hyperthermic intraperitoneal chemoperfusion (CRS-HIPEC), stratified according to the WHO 5th edition and the Tang et al. grading schemes. The patients were also compared with 120 patients with peritoneal metastasis of appendiceal mucinous neoplasia. Most (73%) peritoneal metastases of goblet cell adenocarcinoma were WHO Grade 3 (G3), there being fewer cases of Grade 2 (G2) (16%) and Grade 1 (G1) (11%) disease. No significant differences in overall survival were observed between WHO G1 and G2 tumours or between the three Tang grades. In the multivariable model of survival, WHO G3 [hazard ratio (HR) 2.81, 95% confidence interval (CI) 1.02-7.70] and the presence of >50% extracellular mucin (HR 2.30, 95% CI 1.09-4.88) were associated with reduced overall survival for patients with goblet cell adenocarcinoma. As compared with patients with peritoneal metastasis of mucinous neoplasia, patients with goblet cell adenocarcinoma had significantly reduced survival (median overall survival of 37 months versus 102 months, P < 0.001), which was attributed to the reduced survival of patients with G1/G2 goblet cell adenocarcinoma as compared with patients with G1 mucinous neoplasia (median survival of 98 months versus 204 months, P < 0.001). CONCLUSIONS: Grade of peritoneal goblet cell adenocarcinoma determined according to the WHO 5th edition criteria is a clinically relevant measure that independently predicts survival in patients treated with CRS-HIPEC.

Management and prognostic prediction of appendiceal mucinous adenocarcinoma with peritoneal metastasis: a single center study in China.

BACKGROUND: To investigate the clinical and pathological characteristics of appendiceal mucinous adenocarcinoma with peritoneal metastasis and analyze the prognostic factors. METHODS: A retrospective analyses of clinicopathological features of 50 patients with appendiceal mucinous adenocarcinoma with peritoneal metastasis from January, 2013 to December, 2017 in Aerospace Central Hospital, Beijing, China. Survival data calculation and comparison were respectively performed with the Kaplan-Meier method and the log-rank test. The Cox proportional hazards regression method was used for multivariate survival analyses. RESULTS: Cytoreduction for appendiceal mucinous adenocarcinoma was conducted on 50 patients (24 males and 26 females), with a median age of 52.5 years at the time of surgery (range 31-71 years). The median overall survival (OS) time was 24 months, with 2-,3- and 5-year survival rates of 53, 24 and 8%, respectively. At the last follow-up in December 2018, 13 patients were still alive. Multivariate analysis revealed that patients who had low Ki-67 expression (less than 50%) and CCR (completeness of cytoreduction) 0/1/2 score had significantly better OS rate than their respective counterparts. CONCLUSIONS: Ki-67 expression statue and CCR score could be employed as the prognosis prediction in patients with appendiceal mucinous adenocarcinoma.