Acquired Resistance to KRASG12C Inhibition in Cancer.

BACKGROUND: Clinical trials of the KRAS inhibitors adagrasib and sotorasib have shown promising activity in cancers harboring KRAS glycine-to-cysteine amino acid substitutions at codon 12 (KRASG12C). The mechanisms of acquired resistance to these therapies are currently unknown. METHODS: Among patients with KRASG12C -mutant cancers treated with adagrasib monotherapy, we performed genomic and histologic analyses that compared pretreatment samples with those obtained after the development of resistance. Cell-based experiments were conducted to study mutations that confer resistance to KRASG12C inhibitors. RESULTS: A total of 38 patients were included in this study: 27 with non-small-cell lung cancer, 10 with colorectal cancer, and 1 with appendiceal cancer. Putative mechanisms of resistance to adagrasib were detected in 17 patients (45% of the cohort), of whom 7 (18% of the cohort) had multiple coincident mechanisms. Acquired KRAS alterations included G12D/R/V/W, G13D, Q61H, R68S, H95D/Q/R, Y96C, and high-level amplification of the KRASG12C allele. Acquired bypass mechanisms of resistance included MET amplification; activating mutations in NRAS, BRAF, MAP2K1, and RET; oncogenic fusions involving ALK, RET, BRAF, RAF1, and FGFR3; and loss-of-function mutations in NF1 and PTEN. In two of nine patients with lung adenocarcinoma for whom paired tissue-biopsy samples were available, histologic transformation to squamous-cell carcinoma was observed without identification of any other resistance mechanisms. Using an in vitro deep mutational scanning screen, we systematically defined the landscape of KRAS mutations that confer resistance to KRASG12C inhibitors. CONCLUSIONS: Diverse genomic and histologic mechanisms impart resistance to covalent KRASG12C inhibitors, and new therapeutic strategies are required to delay and overcome this drug resistance in patients with cancer. (Funded by Mirati Therapeutics and others; ClinicalTrials.gov number, NCT03785249.).

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.

Fragmentation of Care in Patients with Peritoneal Metastases Undergoing Cytoreductive Surgery.

BACKGROUND: The delivery of multimodal treatment at a high-volume center is known to optimize the outcomes of gastrointestinal malignancies. However, patients undergoing cytoreductive surgery (CRS) for peritoneal metastases often must 'fragment' their surgical and systemic therapeutic care between different institutions. We hypothesized that this adversely affects outcomes. PATIENTS AND METHODS: Adults undergoing CRS for colorectal or appendiceal adenocarcinoma at our institution between 2016 and 2022 were identified retrospectively and grouped by care network: 'coordinated care' patients received exclusively in-network systemic therapy, while 'fragmented care' patients received some systemic therapy from outside-network providers. Factors associated with fragmented care were also ascertained. Overall survival (OS) from CRS and systemic therapy-related serious adverse events (SAEs) were compared across the groups. RESULTS: Among 85 (80%) patients, 47 (55%) had colorectal primaries and 51 (60%) received fragmented care. Greater travel distance [OR 1.01 (CI 1.00-1.02), p = 0.02] and educational status [OR 1.04 (CI 1.01-1.07), p = 0.01] were associated with receiving fragmented care. OS was comparable between patients who received fragmented and coordinated care in the colorectal [32.5 months versus 40.8 months, HR 0.95 (CI 0.43-2.10), p = 0.89] and appendiceal [31.0 months versus 27.4 months, HR 1.17 (CI 0.37-3.74), p = 0.55] subgroups. The frequency of SAEs (7.8% versus 17.6%, p = 0.19) was also similar. CONCLUSIONS: There were no significant differences in survival or SAEs based on the networks of systemic therapy delivery. This suggests that patients undergoing CRS at a high-volume center may safely receive systemic therapy at outside-network facilities with comparable outcomes.

Enhancing the Efficacy of HIPEC Through Bromelain: A Preclinical Investigation in Appendiceal Cancer.

INTRODUCTION: Appendiceal cancer (AC) excessive mucin production is a barrier to heated intraperitoneal chemotherapy (HIPEC) drug delivery. Bromelain is a pineapple stem extract with mucolytic properties. We explored bromelain treatment effects against mucinous AC in a patient-derived tumor organoid (PTO) model and an AC cell line. PATIENTS AND METHODS: PTOs were fabricated from tumor specimens obtained from patients with AC undergoing cytoreductive surgery with HIPEC. PTOs underwent HIPEC treatment with bromelain, cisplatin, and mitomycin C (MMC) at 37 °C and 42 °C with and without bromelain pretreatment. RESULTS: From October 2020 to May 2023, 16 specimens were collected from 13 patients with low-grade (12/16, 75%) and high-grade AC (4/16, 25%). The mucin-depleting effects of bromelain were most significant in combination with N-acetylcysteine (NAC) compared with bromelain (47% versus 10%, p = 0.0009) or NAC alone (47% versus 12.8%, p = 0.0027). Bromelain demonstrated > 31% organoid viability reduction at 60 min (p < 0.001) and > 66% in 48 h (p < 0.0001). Pretreatment with bromelain increased cytotoxicity of both cisplatin and MMC HIPEC conditions by 31.6% (p = 0.0001) and 35.5% (p = 0.0001), respectively. Ki67, CK20, and MUC2 expression decreased after bromelain treatment; while increased caspase 3/7 activity and decreased Bcl-2 (p = 0.009) and Bcl-xL (p = 0.01) suggest induction of apoptosis pathways. Furthermore, autophagy proteins LC3A/B I (p < 0.03) and II (p < 0.031) were increased; while ATG7 (p < 0.01), ATG 12 (p < 0.04), and Becline 1(p < 0.03), expression decreased in bromelain-treated PTOs. CONCLUSIONS: Bromelain demonstrates cytotoxicity and mucolytic activity against appendiceal cancer organoids. As a pretreatment agent, it potentiates the cytotoxicity of multiple HIPEC regimens, potentially mediated through programmed cell death and autophagy.

[Long-Term Survival of a Case with Peritoneal Dissemination from Appendiceal Goblet Cell Carcinoid Treated with Systemic Chemotherapy].

A 64-year-old man complained of lower abdominal pain and vomiting. The CT scan showed adhesional ileus; therefore, small bowel resection procedure was performed. Histological findings showed signet-ring cell carcinoma and poorly differentiated adenocarcinoma. We performed ileocecal resection as an additional surgery. The operative findings revealed peritoneal nodules. The histological findings suggested goblet cell carcinoid with peritoneal dissemination. mFOLFOX+bevacizumab was administered, and no progression was observed for 30 months after the surgery. Appendiceal goblet cell carcinoid is rare and its prognosis is poor. Here, we report a case of appendiceal GCC that achieved a relatively long-term survival despite peritoneal dissemination.

[A Case of Appendiceal Mucinous Carcinoma with Bladder Invasion Developed from Abscess-Forming Appendicitis, Which Was Curatively Resected after Chemotherapy].

The patient was a 35-year-old man who saw his first doctor with the chief complaint of painful urination. A contrast- enhanced CT scan of the abdomen revealed a diagnosis of abscess-forming appendicitis with inflammatory spread to the bladder, and conservative treatment was decided. Since antibiotic treatment failed to reduce the size of the abscess, he underwent surgery. The bladder wall was highly inflamed, only appendectomy was performed. Pathology revealed appendiceal mucinous carcinoma invading the bladder, so he was referred to our department. Because a total cystectomy was required for curative resection and there was concern about seeding associated with the initial surgery, he was judged to be unresectable, and received chemotherapy. After 6 courses of CAPOX+bevacizumab therapy, he was able to have a bladder- sparing curative resection because of the absence of distant metastasis and shrinkage of the tumor. He remains stable without recurrence 6 months after surgery. We herein report, with some discussion of the literature, this case of bladder-invading appendiceal mucinous carcinoma arising from abscess-forming appendicitis, for which a curative resection was possible after chemotherapy.

Taxane-Based Chemotherapy Is Effective in Metastatic Appendiceal Adenocarcinoma.

Appendiceal cancer is a rare, orphan disease with no therapies currently approved by the FDA for its treatment. Given the limited data regarding drug efficacy, these tumors have historically been treated with chemotherapy designed for colon cancer. However, an overwhelming body of molecular data has demonstrated that appendiceal adenocarcinoma is a distinct entity with key molecular differences from colon cancer, notably rare APC mutation. Recognizing that APC loss-of-function is thought to contribute to taxane resistance and that taxanes are effective in the treatment of other gastrointestinal tumors, including gastric, esophageal, and small bowel adenocarcinoma, we completed a single-center retrospective study to assess efficacy. In a cohort of 13 patients with metastatic appendiceal adenocarcinoma, treated with taxane chemotherapy the median overall survival was 8.8 months. Of 10 evaluable patients, we observed 3 responses, 4 patients with stable disease, and 3 with progression (30% response rate, 70% disease control rate). The results of this study showing activity of taxane-based chemotherapy in appendiceal adenocarcinoma support further clinical investigation of taxane therapy in this orphan disease.

Safety and Efficacy of Oxaliplatin Pressurized Intraperitoneal Aerosolized Chemotherapy (PIPAC) in Colorectal and Appendiceal Cancer with Peritoneal Metastases: Results of a Multicenter Phase I Trial in the USA.

BACKGROUND: Pressurized intraperitoneal aerosolized chemotherapy (PIPAC) is a laparoscopic locoregional treatment for peritoneal metastases (PM) from colorectal cancer (CRC) or appendiceal cancer (AC) in patients who cannot undergo cytoreductive surgery (CRS). While PIPAC has been studied in Europe and Asia, it has not been investigated in the USA. PATIENTS AND METHODS: We evaluated PIPAC with 90 mg/m2 oxaliplatin alone (cycle 1) and preceded by systemic chemotherapy with fluorouracil (5-FU) and leucovorin (LV) (cycle 2-3) as a multicenter prospective phase I clinical trial (NCT04329494). The primary endpoint was treatment-related adverse events (AEs). Secondary endpoints included survival and laparoscopic, histologic, and radiographic response. RESULTS: 12 patients were included: 8 with CRC and 4 with AC. Median prior chemotherapy cycles was 2 (interquartile range (IQR) 2-3). All patients were refractory to systemic oxaliplatin-based chemotherapy. Median peritoneal carcinomatosis index (PCI) was 28 (IQR 19-32). Six (50%) of twelve patients completed three PIPAC cycles. No surgical complications or dose-limiting toxicities were observed. Two patients developed grade 3 treatment-related toxicities (one abdominal pain and one anemia). Median overall survival (OS) was 12.0 months, and median progression-free survival (PFS) was 2.9 months. OS was correlated with stable disease by Response Evaluation Criteria in Solid Tumors (RECIST) criteria but not with laparoscopic response by PCI or histologic response by peritoneal regression grading system (PRGS). CONCLUSIONS: This phase I trial in the USA demonstrated safety, feasibility, and early efficacy signal of PIPAC with oxaliplatin and chemotherapy in patients with PM from AC or CRC who are refractory to standard lines of systemic chemotherapy.

Cancer embryonic antigen (CEA) levels in patients with appendiceal adenocarcinoma predict response to neo-adjuvant chemotherapy and overall survival.

BACKGROUND AND OBJECTIVES: Serum tumor markers are widely used for diagnosis, prognosis, treatment response, and surveillance. Our study evaluated cancer embryonic antigen (CEA) in patients with appendiceal adenocarcinoma. METHODS: The National Cancer Database was reviewed (2004-2011) for patients with surgical treatment for appendiceal adenocarcinoma. Patients were stratified into two groups: normal and elevated CEA. Multivariable adjusted Cox proportional hazards regression analyses were used to determine the independent effect of CEA on survival. RESULTS: Our study consisted of 2867 patients, 54.0% having elevated CEA. Patients with elevated CEA were more likely to have Stage IV disease, be female, and African American; all p < 0.001. Three-year overall survival (OS) was significantly higher with normal CEA (75.5% vs. 62.8%, p < 0.001). On multivariable analysis, elevated CEA was associated with worse survival (hazard ratio 1.49, 95% confidence interval 1.23-1.80). Patients with elevated CEA had improved 3-year OS with neo-adjuvant compared to adjuvant chemotherapy (p = 0.004), while those with normal CEA showed no difference. CONCLUSIONS: In patients with surgically treated appendiceal adenocarcinoma, preoperative elevation in CEA independently predicts decreased 3-year survival and correlates with improved OS with neo-adjuvant therapy. CEA levels should be considered in clinical decision-making regarding neo-adjuvant therapy in patients with appendiceal adenocarcinoma.

[A Case of Goblet Cell Adenocarcinoma Incidentally Diagnosed after Appendectomy That Required Additional Bowel Resection with Lymph Nodes Dissection].

A 54-year-old male presented to the clinic, complaining of dull lower abdominal pain that started a day ago. There was a tenderness on right lower quadrant on palpation and abdominal computed tomography(CT)showed that dilated appendix with a diameter of 12 mm. The patient was diagnosed with acute appendicitis and laparoscopic appendectomy was performed on the same day. The tip of the appendix was swollen and looked purple, gangrenous appendicitis findings were identified. However, histopathology detected GCA on resected appendix with positive surgical margin and additional tumor resection was indicated. Laparoscopic ileocecal resection with D3 lymph nodes dissection was performed 24 days after the first surgery. Resected specimen showed that the stump of the appendix was palpable as a mass in the orifice of the appendix and histopathology revealed the remnant of the appendiceal GCA. No lymph nodes tumor metastasis was identified. Chromogranin A and synaptophysin were positive and Ki-67 was approximately 50%. According to the guideline of neoadjuvant chemotherapy for colon cancer, oral 5-fluorouracil therapy was performed for half a year after the second surgery and the patient remains still healthy without recurrence 1 year after the surgery. Here, we experienced a rare case of GCA of the appendix that was detected incidentally after appendectomy for acute appendicitis.

Repeat Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy for Cancers with Peritoneal Metastasis: A 30-year Institutional Experience.

BACKGROUND: Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) improves survival in abdominal cancer patients with metastatic disease limited to the peritoneal cavity. Patients are increasingly being offered repeat CRS-HIPECs for peritoneal recurrence. However, in this rare clinical scenario, the survival benefit of performing repeat CRS-HIPEC operations remains unclear. METHODS: A retrospective review of the CRS-HIPEC database at Wake Forest Baptist Medical Center was performed over a 30-year timespan. From 1547 patients with appendix cancers, colorectal cancers, mesotheliomas, and other miscellaneous cancers, 156 received more than one CRS-HIPEC. Kaplan-Meier survival analysis was performed using overall survival (OS) from the time of surgery as the primary endpoint. Multi-variable Cox proportional hazards regression modelling was performed on pertinent clinical variables. RESULTS: Patients who received multiple CRS-HIPECs had significantly better median OS (10.7 years) versus those who received one CRS-HIPEC (2.5 years), with appendix cancers faring best (12.9 years). Resection status R2a or better was achieved in 76.4% of repeat CRS-HIPECs. There were no significant changes in complication rates after repeat CRS-HIPEC. On multivariate analysis of repeat CRS-HIPEC, patients with appendix and colorectal cancers, heart disease, and poor functional status were independently associated with poor OS. Factors not independently associated with OS were age, sex, body mass index, race, diabetes, lung disease, smoking history, and systemic chemotherapy between CRS-HIPECs. CONCLUSIONS: Performing multiple CRS-HIPEC operations on appropriate surgical candidates may significantly prolong survival. Appendix cancers derived the greatest benefit. Satisfactory resection margins and complication rates are comparable to first cases and achievable in repeat CRS-HIPEC procedures.

Outcomes and prognostic factors of cytoreductive surgery and perioperative intraperitoneal chemotherapy in high-volume peritoneal carcinomatosis.

BACKGROUND AND OBJECTIVES: The management of patients with extensive appendiceal mucinous neoplasms and mesothelioma is controversial. Our aims were to analyze overall survival (OS), disease-free survival (DFS) and independent prognostic factors associated with high peritoneal cancer index (PCI) status in patients who underwent cytoreductive surgery (CRS) and perioperative intraperitoneal chemotherapy (PIC). METHODS: A prospectively-maintained database for patients with appendiceal neoplasms and mesothelioma undergoing CRS/PIC from year 1996 to 2018 was retrospectively analyzed. Patients who achieved complete cytoreduction were stratified into limited (PCI < 30) and extensive (PCI ≥ 30) disease groups. RESULTS: 260 female and 235 male patients were identified. The 5-year survival for low-grade appendiceal mucinous neoplasms (LAMN) was significantly higher in the low PCI group (96.2% vs. 63.5%, p < 0.001). There was no difference in the OS across both groups in high-grade appendiceal mucinous neoplasms (HAMN) (63 vs. 69 months; p = 0.942) and mesothelioma (72 vs. 42 months; p = 0.058). Overall mortality was 2%. Grade III/IV complications were significantly higher in extensive disease (68% vs. 36.6%, p < 0.001). On multivariate analysis, use of EPIC and blood transfusion (>8 units) were independent positive and negative prognostic factors, respectively, associated with OS. Meanwhile, use of EPIC conferred benefit in DFS while increased blood transfusion (>8 units) and elevated preoperative CA125 were predictive of a poor DFS. CONCLUSION: Long-term survivals following CRS/PIC are achievable with acceptable mortality and higher morbidity rates in extensive appendiceal mucinous neoplasms and mesothelioma. High PCI status does not preclude treatment with CRS/PIC.

A Canadian single-centre experience with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for abdominal malignancies.

BACKGROUND: Cytoreductive surgery in combination with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) has recently shown promise for the treatment of patients with various types of peritoneal carcinomatosis (PC). However, it is an extensive procedure that is associated with a variety of morbidities. We evaluated the safety and clinical outcomes of CRS-HIPEC performed at our centre. METHODS: Patients with abdominal malignancies who underwent CRS-HIPEC between February 2005 and December 2018 at the Centre hospitalier de l'Université de Montréal (CHUM) were retrospectively reviewed. RESULTS: A total of 141 patients were identified (66 with appendiceal cancer, 62 with colorectal cancer, 10 with mesothelioma and 3 with small intestinal tumours). The median age was 55 years. Median overall survival (OS) was not reached for patients with appendiceal tumours; it was 38.3 months for colorectal cancers. Among patients with colorectal cancer, survival was significantly better for those who received intraperitoneal HIPEC with oxaliplatin (74.9 mo) compared with mitomycin C (29.1 mo) (p = 0.006). Complete cytoreductive surgery and low peritoneal carcinomatosis index were associated with the highest overall survival in patients with appendiceal tumours and those with colorectal tumours. CONCLUSION: CRS-HIPEC can be performed with acceptable morbidity in patients with PC. These results validate the outcomes of previously reported trials, but further prospective trials are warranted to determine which patients will most benefit from the addition of HIPEC to CRS.

The Role of Adjuvant Chemotherapy in Non-Metastatic Goblet Cell Carcinoid of the Appendix: An 11-Year Experience from the National Cancer Database.

BACKGROUND: Goblet cell carcinoids (GCC) are an aggressive, albeit rare, subtype of appendiceal tumors that exhibit distinct histologic features and lack clear treatment guidelines. We aimed to ascertain the impact of adjuvant chemotherapy (AC) for GCC in a national cohort of patients. METHODS: Patients who underwent a right hemicolectomy for stage I-III GCC of the appendix between 2006 and 2016 were selected from the National Cancer Database (NCDB). Stratification based on AC receipt was performed. Kaplan-Meier survival estimates and Cox proportional hazard regression were used to identify predictors of overall survival (OS). RESULTS: A total of 867 patients were identified, of whom 124 (14%) received AC. Patients in the AC group were significantly younger (54 vs. 57 years; p = 0.006) and were predominantly of male sex (60 vs. 48%; p = 0.012). On histopathology, patients in the AC group had a higher proportion of poorly/undifferentiated grade (27 vs. 5%; p < 0.001), T4 disease (35 vs. 11%; p < 0.001), and lymph node-positive disease (45 vs. 7%; p < 0.001) than patients who did not receive AC. After excluding patients diagnosed in 2016 due to a lack of follow-up data (n = 162), a survival advantage for the AC group was detected only after stratification for lymph node-positive disease (p = 0.007). On Cox proportional hazard regression, AC demonstrated an independent association with improved OS (hazard ratio 0.24, 95% confidence interval 0.084-0.683; p = 0.007). CONCLUSION: The current analysis from the NCDB supports the role of AC for GCC of the appendix, chiefly for patients with lymph node metastatic disease.

Chemotherapy in the treatment of different histological types of appendiceal cancers: a SEER based study.

BACKGROUND: Due to its rarity and high heterogeneity, neither established guidelines nor prospective data are currently available for using chemotherapy in the treatment of appendiceal cancer. This study was to determine the use of chemotherapy and its potential associations with survival in patients with different histological types of the cancer. METHODS: Patients with histologically different appendiceal cancers diagnosed during 1998-2016 were selected from the Surveillance, Epidemiology, and End Results (SEER) database. The role and effect of chemotherapy were examined in the treatment of the disease. The Kaplan-Meier method was applied to construct survival curves and significance was examined by Log-rank test. Cox proportional hazard models were used to analyze the impact of chemotherapy and other variables on survival in these patients. RESULTS: A total of 8733 appendiceal cancer patients were identified from the database. Chemotherapy was administrated at highly variable rates in different histological types of appendiceal cancer. As high as 64.0% signet ring cell carcinoma (SRCC), 46.4% of mucinous adenocarcinomas (MAC), 40.6% of non-mucinous adenocarcinoma (NMAC) and 43.9% of mixed neuroendocrine non-neuroendocrine neoplasms (MiNENs) were treated with chemotherapy, whereas only 14.7% of goblet cell carcinoma (GCC), 5% neuroendocrine tumors (NETs) and 1.6% carcinomas (NEC) received chemotherapy. In all patients combined, chemotherapy significantly improved overall survival during the entire study period and cancer-specific survival was improved during in cases from 2012-2016. Further multivariate analysis showed that both cancer-specific and overall survival was significantly improved with chemotherapy  in patients with MAC, NMAC and SRCC, but not for patients with GCC, MiNENs, NETs and NECs. Number (> 12) of lymph node sampled was associated with survival of patients with most histological types of cancer under study. Other prognostic factors related to individual histological types were identified. CONCLUSIONS: Chemotherapy is administrated at highly variable rates in different histological types of appendiceal cancer. Efficacy of chemotherapy in the treatment of these cancers has been improved in recent years and is significantly associated with better survival for patients with NMAC, MAC, and SRCC. Adequate lymph node sampling may result in a survival benefit for most of these patients.

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.

Treatment of advanced pseudomyxoma peritonei using cytoreductive surgery including total gastrectomy and perioperative chemotherapy.

BACKGROUND: Pseudomyxoma peritonei is a disease caused by the widespread distribution of mucinous tumor into the peritoneal space from a perforated appendiceal neoplasm. METHODS: All patients in this study had cytoreductive surgery with total gastrectomy plus perioperative intraperitoneal chemotherapy. A high diverting jejunostomy was used on all patients. Patient characteristics, adverse events, and survival were accumulated prospectively. RESULTS: Fifty-eight patients were available for long-term follow-up. In the univariate analysis, features associated with a less favorable outcome included female gender (p = 0.0127), intestinal obstruction before treatment (p = 0.00791), and prior surgical score (PSS) (p = 0.0054). In the multivariate analysis, the two significant variables were grade (p = 0.0458) and PSS (p = 0.0041). Median survival was 12 years with a 5-, 10-, and 20-year survival of 76%, 58%, and 37%, respectively. There were two postoperative deaths (3.4%) and Grades 3 and 4 adverse events in 20 (34.5%) patients. CONCLUSIONS: A 10-year survival after cytoreductive surgery, total gastrectomy with temporary high diverting jejunostomy, and perioperative chemotherapy occurred in 58% of these patients with advanced pseudomyxoma peritonei. High-grade disease and extensive prior surgery with a high PSS were associated with reduced benefit.

Morbidity associated with the use of oxaliplatin versus mitomycin C in hyperthermic intraperitoneal chemotherapy (HIPEC) for peritoneal carcinomatosis of colorectal or appendiceal origin: a multi-institutional comparative study.

Background: The raw costs of mitomycin C (MMC) and oxaliplatin for hyperthermic intraperitoneal chemotherapy (HIPEC) differ substantially. We sought to compare the morbidity and toxicity profiles associated with the use of oxaliplatin and MMC in patients undergoing cytoreductive surgery (CRS) and HIPEC for peritoneal carcinomatosis (PC) of colorectal or appendiceal origin, to evaluate whether the costeffectiveness of these 2 agents should dictate drug choice. Methods: We conducted a retrospective multi-institutional study of all patients with PC of colorectal or appendiceal origin treated with CRS-HIPEC using MMC or oxaliplatin from 2010 to 2015. Demographic, perioperative, morbidity, toxicity and cost data were compared between the 2 treatment groups and between cancer-origin subgroups. Results: Forty-two patients treated with MMC and 76 treated with oxaliplatin were included in the study. Baseline demographic and tumour characteristics were comparable in the 2 groups, except that the patients treated with MMC had higher Charlson Comorbidity Index scores. The MMC group had a higher rate of cancer of colorectal origin (76.2% v. 57.9%, p = 0.047) and longer operative times (553 v. 320 min, p < 0.001). In the subgroup of patients whose cancer was of colorectal origin, patients treated with MMC had a higher transfusion rate (50.0% v. 28.6%, p = 0.023) and lower postoperative baseline hemoglobin level (100 v. 119 g/L, p = 0.002) than those treated with oxaliplatin. There was no difference in hematologic toxicity scores after controlling for postoperative anemia. There was no difference in the rates of major complications and 90-day mortality. However, MMC was less costly than oxaliplatin ($724 v. $8928). Conclusion: MMC and oxaliplatin are both suitable agents for HIPEC and are associated with comparable morbidity and toxicity profiles, regardless of cancer origin. Thus, we propose that cost-effectiveness should ultimately dictate drug selection.

Contexte: Les coûts bruts de la mitomycine C (MMC) et de l'oxaliplatine pour la chimiothérapie hyperthermique intrapéritonéale (CHIP) sont très différents. Nous avons voulu comparer la morbidité et la toxicité associées à l'oxaliplatine et à la MMC chez les patients subissant une chirurgie de réduction tumorale (CRT) et une CHIP pour une carcinomatose péritonéale (CP) d'origine colorectale ou appendiculaire afin d'évaluer si le choix des professionnels de la santé devrait reposer sur le rapport coût­efficacité de ces médicaments. Méthodes: Nous avons mené une étude multicentrique rétrospective sur tous les patients qui, entre 2010 et 2015, présentaient une CP d'origine colorectale ou appendiculaire et ont subi une CRT ainsi qu'une CHIP à la MMC ou à l'oxaliplatine. Les données relatives aux caractéristiques démographiques, aux résultats périopératoires, à la morbidité, à la toxicité et aux coûts ont été comparées entre les 2 groupes de traitement et entre les sous-groupes formés en fonction de l'origine du cancer. Résultats: Au total, 42 patients traités à la MMC et 76 patients traités à l'oxaliplatine ont été inclus dans l'étude. Les caractéristiques démographiques et tumorales des 2 groupes avant le traitement étaient semblables, à l'exception de l'indice de comorbidité de Charlson, qui était plus élevé dans le groupe MMC. Le groupe MMC présentait un taux plus important de cancer d'origine colorectale (76,2 % c. 57,9 %; p = 0,047), de même qu'un temps opératoire plus long (553 min c. 320 min; p < 0,001). En ce qui concerne le sous-groupe de patients atteints d'un cancer d'origine colorectale, les personnes traitées à la MMC affichaient un taux de transfusion plus élevé (50,0 % c. 28,6 %; p = 0,023) et un taux d'hémoglobine postopératoire de référence plus bas (100 g/L c. 119 g/L; p = 0,002) que celles traitées à l'oxaliplatine. Une fois l'anémie postopératoire prise en compte, aucune différence n'a été observée quant à la toxicité hématologique. Les taux de complications majeures et de mortalité à 90 jours étaient aussi comparables. La MMC coûtait toutefois moins cher que l'oxaliplatine (724 $ c. 8928 $). Conclusion: La MMC et l'oxaliplatine conviennent à la CHIP, et la morbidité et la toxicité qui y sont associées sont comparables, quelle que soit l'origine du cancer. Nous proposons donc que le choix du médicament à utiliser repose sur le rapport coût­efficacité.

Defining "Complete Cytoreduction" After Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy (CRS/HIPEC) for the Histopathologic Spectrum of Appendiceal Carcinomatosis.

BACKGROUND: The completeness of cytoreduction (CC) score, which quantifies residual tumor, is a major prognostic factor when treating appendiceal carcinomatosis with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). Both CC-0 and CC-1 are considered complete cytoreductions (CC-0/1) and associated with the best outcomes. We analyzed if the CC-0/1 definition is reliable across appendiceal histopathologic subtypes. METHODS: A prospective database of CRS/HIPEC patients with appendiceal carcinomatosis from 1998 to 2019 was reviewed to identify patients with CC-0/1. Kaplan-Meier overall survival (OS) and progression-free survival (PFS) by CC-score for each histopathology were calculated. RESULTS: Overall, 297 patients had CC-0/1. Mean age was 54 ± 12 years with 67% females. Histopathologic subtypes were 45% low-grade mucinous carcinoma peritonei (LGMCP), 27% high-grade MCP (HGMCP), 20% HGMCP with signet ring cells (HGMCP-S), and 8% goblet cell adenocarcinoma (GCAC). CC-0 and CC-1 occurred in 57% and 43% of LGMCP, 65% and 35% of HGMCP, 68% and 32% of HGMCP-S, and 79% and 21% of GCAC, respectively. OS and PFS were statistically longer for CC-0 versus CC-1 in HGMCP-S (p = 0.001 and p = 0.005, respectively) and GCAC (p < 0.001 and p < 0.001), but not in LGMCP (p = 0.098 and p = 0.398) or HGMCP (p = 0.167 and p = 0.356). CONCLUSIONS: Survival outcomes for CC-0 and CC-1 after CRS/HIPEC are different for HGMCP-S and GCAC but not for LGMCP and HGMCP. In HGCMP-S and GCAC, only CC-0 should be considered a complete cytoreduction and analyzed separately from CC-1. This distinction is key to understand disease behavior, accurately address patient prognosis, and explore new treatment strategies.

Implications of Postoperative Complications for Survival After Cytoreductive Surgery and HIPEC: A Multi-Institutional Analysis of the US HIPEC Collaborative.

BACKGROUND: Postoperative complications (POCs) are associated with worse oncologic outcomes in various cancer histologies. The impact of POCs on the survival of patients with appendiceal or colorectal cancer after cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC) is unknown. METHODS: The US HIPEC Collaborative (2000-2017) was reviewed for patients who underwent CCR0/1 CRS/HIPEC for appendiceal/colorectal cancer. The analysis was stratified by noninvasive appendiceal neoplasm versus invasive appendiceal/colorectal adenocarcinoma. The POCs were grouped into infectious, cardiopulmonary, thromboembolic, and intestinal dysmotility. The primary outcomes were overall survival (OS) and recurrence-free survival (RFS). RESULTS: Of the 1304 patients, 33% had noninvasive appendiceal neoplasm (n = 426), and 67% had invasive appendiceal/colorectal adenocarcinoma (n = 878). In the noninvasive appendiceal cohort, POCs were identified in 55% of the patients (n = 233). The 3-year OS and RFS did not differ between the patients who experienced a complication and those who did not (OS, 94% vs 94%, p = 0.26; RFS, 68% vs 60%, p = 0.15). In the invasive appendiceal/colorectal adenocarcinoma cohort, however, POCs (63%; n = 555) were associated with decreased 3-year OS (59% vs 74%; p < 0.001) and RFS (32% vs 42%; p < 0.001). Infectious POCs were the most common (35%; n = 196). In Multivariable analysis accounting for gender, peritoneal cancer index (PCI), and incomplete resection (CCR1), infectious POCs in particular were associated with decreased OS compared with no complication (hazard ratio [HR] 2.08; p < 0.01) or other types of complications (HR, 1.6; p < 0.01). Similarly, infectious POCs were independently associated with worse RFS (HR 1.61; p < 0.01). CONCLUSION: Postoperative complications are associated with decreased OS and RFS after CRS/HIPEC for invasive histology, but not for an indolent disease such as noninvasive appendiceal neoplasm, and this association is largely driven by infectious complications. The exact mechanism is unknown, but may be immunologic. Efforts must target best practices and standardized prevention strategies to minimize infectious postoperative complications.