Do Lymph Node Metastases Matter in Appendiceal Cancer with Peritoneal Carcinomatosis? A US HIPEC Collaborative Study.

BACKGROUND: Whether formal regional lymph node (LN) evaluation is necessary for patients with appendiceal adenocarcinoma (AA) who have peritoneal metastases is unclear. The aim of this study was to evaluate the prognostic value of LN metastases on survival in patients treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). METHODS: A retrospective analysis of the US HIPEC collaborative, a multi-institutional consortium comprising 12 high-volume centers, was performed to identify patients with AA who underwent CRS-HIPEC with adequate LN sampling (≥ 12 LNs). RESULTS: Two hundred-fifty patients with AA who underwent CRS-HIPEC were included. Outcomes were compared between LN - and LN + disease. Baseline patient characteristics between groups were similar, with most patients undergoing complete cytoreduction (0/1: 86.0% vs. 76.8%, p = 0.08), respectively. More adverse tumor factors were found in patients with LN + disease, including poor differentiation, signet ring cells, and lymphovascular invasion. Multivariate analysis of overall survival (OS) found LN + disease was independently associated with worse OS (HR: 2.82 95%CI: 1.25-6.34, p = 0.01), even after correction for receipt of systemic therapy. On Kaplan-Meier analysis, median OS was lower in patients with LN + disease (25.9 months vs. 91.4 months, p < 0.01). LN + disease remained associated with poor OS following propensity score matching (HR: 4.98 95%CI: 1.72-14.40, p < 0.01) and in patients with PCI ≥ 20 (HR: 3.68 95%CI: 1.54-8.80, p < 0.01). CONCLUSIONS: In this large multi-institutional study of patients with AA undergoing CRS-HIPEC, LN status remained associated with worse OS even in the setting of advanced peritoneal carcinomatosis. Formal LN evaluation should be performed for most patients with AA undergoing CRS-HIPEC.

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

BACKGROUND: Peritoneal carcinomatosis, from a variety of gastrointestinal and gynecological malignancies, has been historically challenging to treat and there remains a wide range of biologic aggressiveness in these patients. Malignancies commonly associated with PC include those of colorectal, appendiceal, gastric, ovarian, sarcoma, small intestinal, and primary peritoneal origin among others. Advances in our understanding of this unique disease process have led to significant interest in cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) as an emerging treatment option. The goal of CRS-HIPEC is to remove all visible macroscopic disease while preserving organ function, and then treat microscopic disease through perfusion of the peritoneal cavity with heated chemotherapy. PURPOSE: Although recent reviews have focused on the management of peritoneal carcinomatosis secondary to colorectal cancer given the publication of several recent randomized controlled trials, the purpose of the current review is to summarize the evidence on CRS-HIPEC for non-colorectal peritoneal surface malignancies, including appendiceal neoplasms, malignant peritoneal mesothelioma, gastric cancer, and ovarian cancer. RESULTS: While retrospective studies have clarified the importance of prognostic factors such as the peritoneal carcinomatosis index, completeness of cytoreduction, histopathological characteristics, and lymph node positivity, the lack of convincing level 1 evidence for the use of CRS-HIPEC has led to it remaining a highly controversial topic. CONCLUSION: The decision to utilize CRS-HIPEC should involve a multidisciplinary team approach and evaluation of prognostic factors to balance the short-term morbidity of the operation with maximum long-term benefits. Large, multi-institutional groups and ongoing trials hold promise for clarifying the role of CRS-HIPEC in peritoneal surface malignancies.

The impact of HIPEC vs. EPIC for the treatment of mucinous appendiceal carcinoma: a study from the US HIPEC collaborative.

INTRODUCTION: Mucinous appendiceal carcinoma is a rare malignancy that commonly spreads to the peritoneum leading to peritoneal metastases. Complete cytoreduction with perioperative intraperitoneal chemotherapy (PIC) is the mainstay of treatment, administered as either hyperthermic intra peritoneal chemotherapy (HIPEC) or early post-operative intraperitoneal chemotherapy (EPIC). Our goal was to assess the perioperative and long term survival outcomes associated with these two PIC methods. MATERIALS AND METHODS: Patients with mucinous appendiceal carcinoma were identified in the US HIPEC Collaborative database from 12 academic institutions. Patient demographics, clinical characteristics, and survival outcomes were compared among patients who underwent HIPEC vs. EPIC with inverse probability weighting (IPW) used for adjustment. RESULTS: Among 921 patients with mucinous appendiceal carcinoma, 9% underwent EPIC while 91% underwent HIPEC. There was no difference in Grade III-V complications between the two groups (18.5% for HIPEC vs. 15.0% for EPIC, p=.43) though patients who underwent HIPEC had higher rates of readmissions (21.2% vs. 8.8%, p<.01). Additionally, PIC method was not an independent predictor for overall survival (OS) or recurrence-free survival (RFS) after adjustment on multivariable analysis. CONCLUSIONS: Among patients with mucinous appendiceal carcinoma, both EPIC and HIPEC appear to be associated with similar perioperative and long-term outcomes.

Adjuvant Hyperthermic Intraperitoneal Chemotherapy (HIPEC) for patients at High-Risk of Peritoneal Metastases.

BACKGROUND: Selection of patients for hyperthermic intraperitoneal chemotherapy (HIPEC) continues to evolve. We hypothesized that adjuvant HIPEC for patients at high-risk of peritoneal progression is safe and associated with favorable outcomes. METHODS: The institutional database of a high-volume center was queried for patients with high-risk disease undergoing HIPEC with a peritoneal carcinomatosis index (PCI) of 0. High-risk patients were defined as those with ruptured primary tumors or locally advanced (T4) disease. RESULTS: 37 patients underwent adjuvant HIPEC, with a median follow-up of 5.2 years. 54% had low-grade (LG) tumors while 46% had high-grade (HG) tumors. No patients underwent neoadjuvant chemotherapy, while eleven patients (32.4%) received adjuvant chemotherapy. There were no perioperative mortalities, and the overall complication rate was 43%. For the entire cohort, five year recurrence-free survival (RFS) and overall survival (OS) were 77% and 100%, respectively. Five year RFS and OS were 75% and 100% for LG patients and 81% and 100% for HG patients, respectively. CONCLUSIONS: Adjuvant HIPEC for patients at high-risk of peritoneal progression, with PCI 0, is safe and associated with favorable long-term survival. Additional prospective investigation is needed to identify patient populations who may benefit most from HIPEC.

Incidence and Long-term Outcomes of Patients Requiring Early Reoperation After HIPEC.

BACKGROUND: Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC) remains a formidable operation associated with considerable morbidity. It is unclear how often these patients require reoperation for postoperative complications and if the need for reoperations leads to worse long-term outcomes. METHODS: The Peritoneal Surface Malignancy Database at a single center was retrospectively queried. Out of 149 entries, 141 HIPECs performed between 2012 and 2018 met inclusion criteria. Patients were categorized based on early reoperation (<60 d after HIPEC), and demographic and tumor factors were compared using univariate analyses. Recurrence was calculated for patients with complete cytoreduction and overall survival analyzed using the Kaplan-Meier method. RESULTS: There were 15 reoperations after 141 HIPECs (10.6%). Median duration between HIPEC and reoperation was 18 d. Indications for reoperation included intra-abdominal infection (n = 5), bowel obstruction (n = 4), wound infection (n = 3), bleeding (n = 2), and evisceration (n = 1). There were no identified patient- or tumor-related risk factors for reoperation. Reoperations were associated with longer hospital length of stay (19 versus 9 d, P = 0.005) and 30-d readmissions (46.7% versus 12.8%, P = 0.003). There was no significant difference in 3-year recurrence-free survival, but there was a significant association between reoperation and 3-year overall survival (38.0% versus 71.9%, P = 0.03). CONCLUSIONS: Complications requiring reoperation after HIPEC lead to increased short-term morbidity, longer hospital length of stay, and most importantly, reduced overall survival. Further studies investigating interventions to decrease complications and reduce reoperation rates are needed to improve outcomes after HIPEC.