The contemporary management of peritoneal metastasis: A journey from the cold past of treatment futility to a warm present and a bright future.

Peritoneal metastasis (PM) is often regarded as a less frequent pattern of spread; however, collectively across all spectra of primary tumors, the consequences of PM impact a large population of patients annually. Unlike other modes of metastasis, symptoms at presentation or during the treatment course are common, representing an additional challenge in the management of PM. Early efforts with chemotherapy and incomplete surgical interventions transiently improved symptoms, but durable symptom control and survival extension were rare, which established a perspective of treatment futility for PM through most of the 20th century. Notably, the continued development of better systemic therapy combinations, optimization of cytoreductive surgery (CRS), and rigorous investigation of combining regional therapy-specifically hyperthermic intraperitoneal chemotherapy-with CRS, have resulted in more effective multimodal treatment options for patients with PM. In this article, the authors provide a comprehensive review of the data establishing the contemporary approach for tumors with a high frequency of PM, including appendix, colorectal, mesothelioma, and gastric cancers. The authors also explore the emerging role of adding hyperthermic intraperitoneal chemotherapy to the well established paradigm of CRS and systemic therapy for advanced ovarian cancer, as well as the recent clinical trials identifying the efficacy of poly(adenosine diphosphate ribose) polymerase maintenance therapy. Finally, recent data are included that explore the role of precision medicine technology in PM management that, in the future, may help further improve patient selection, identify the best systemic therapy regimens, detect actionable mutations, and identify new targets for drug development.

Does Hospital Operative Volume Influence the Outcomes of Patients After Heated Intraperitoneal Chemotherapy for Peritoneal Carcinomatosis?

BACKGROUND: For some cancer operations, center volume is associated with improved patient outcomes. Whether this association is true for cytoreductive surgery/heated intraperitoneal chemotherapy (CRS/HIPEC) is unclear. Given the rapidly expanding use of CRS/HIPEC, the aim of this analysis was to determine whether a volume-outcome relationship exists for this strategy. METHODS: The Vizient Clinical Database® was queried for CRS/HIPEC cases from January 2020 through December 2022. Low-, medium-, and high-volume designations were made by sorting hospitals by case volume and creating equal tertiles based on total number of cases. Analysis was performed via one-way ANOVA with post-hoc Tukey test, as indicated. RESULTS: In the 36-month study period, 5165 cases were identified across 149 hospitals. Low- (n = 113), medium- (n = 25), and high-volume (n = 11) centers performed a median of 4, 21, and 47 cases per annum, respectively. Most cases were performed for appendiceal (39.3%) followed by gynecologic neoplasms (20.4%). Groups were similar with respect to age, gender, race, comorbidities, and histology. Low-volume centers were more likely to utilize the ICU post-operatively (59.6% vs. 40.5% vs. 36.3%; p = 0.02). No differences were observed in morbidity (9.4% vs. 7.1% vs. 9.0%, p = 0.71), mortality (0.9% vs. 0.6% vs. 0.7%, p = 0.93), length of stay (9.3 vs. 9.4 vs. 10 days, p = 0.83), 30-day readmissions (5.6% vs. 5.6% vs. 5.6%, p = 1.0), or total cost among groups. CONCLUSIONS: No association was found between CRS/HIPEC hospital volume and post-operative outcomes. These data suggest that in academic medical centers with HIPEC programs, outcomes for commonly treated cancers are not associated with hospital volume.

Comparison of Outcomes in Bowel Resections by Gynecologic Oncologists Versus General Surgeons During Maximal Cytoreductive Surgery for Advanced Ovarian Cancer: Gynecologic Oncology Research Investigators Collaboration Study (GORILLA-3006).

BACKGROUND: This report describes the oncologic outcomes for patients with advanced ovarian cancer who had bowel surgery performed by gynecologic oncologists (GOs) and compares the outcomes with those for bowel surgery performed by general surgeons (GSs) during maximal cytoreductive surgery. METHODS: Patients from six academic institutions who had FIGO stage III or IV ovarian cancer and underwent any bowel surgeries during maximal cytoreductive surgery were eligible for the study. The patients were divided into two groups according to whether bowel surgery was performed by a GO or a GS. In both groups, the GOs were mainly involved in extra bowel debulking procedures. Perioperative and survival outcomes were compared between the two groups. RESULTS: The 761 patients in this study included 113 patients who underwent bowel surgery by a GO and 648 who had bowel surgery by a GS. No discernible differences were observed in age, American Society of Anesthesiology (ASA) score, FIGO stage, histologic type, timing of cytoreductive surgery (primary or interval debulking surgery), or complications between the two groups. The GO group exhibited a shorter operation time than the GS group. Kaplan-Meier analysis showed no survival differences between the two groups. In the Cox analysis, non-serous cell types and gross residual diseases were associated with adverse effects on overall survival. However, performance of bowel surgery by a GO did not have an impact on survival. CONCLUSION: Performance of bowel surgery by a GO during maximal cytoreductive surgery is both feasible and safe. These results should be reflected in the training system for GOs regarding bowel surgery, and further research is needed to confirm that GOs can play a more leading role in performing extra-uterine procedures.

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.

Towards Equal Access to Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy and Survival in Patients with Isolated Colorectal Peritoneal Metastases: A Nationwide Population-Based Study.

BACKGROUND: Before 2016, patients with isolated synchronous colorectal peritoneal metastases (PMCRC) diagnosed in expert centers had a higher odds of undergoing cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) and better overall survival (OS) than those diagnosed in referring centers. Nationwide efforts were initiated to increase awareness and improve referral networks. METHODS: This nationwide study aimed to evaluate whether the between-center differences in odds of undergoing CRS-HIPEC and OS have reduced since these national efforts were initiated. All patients with isolated synchronous PMCRC diagnosed between 2009 and 2021 were identified from the Netherlands Cancer Registry. Associations between hospital of diagnosis and the odds of undergoing CRS-HIPEC, as well as OS, were assessed using multilevel multivariable regression analyses for two periods (2009-2015 and 2016-2021). RESULTS: In total, 3948 patients were included. The percentage of patients undergoing CRS-HIPEC increased from 17.2% in 2009-2015 (25.4% in expert centers, 16.5% in referring centers), to 23.4% in 2016-2021 (30.2% in expert centers, 22.6% in referring centers). In 2009-2015, compared with diagnosis in a referring center, diagnosis in a HIPEC center showed a higher odds of undergoing CRS-HIPEC (odds ratio [OR] 1.64, 95% confidence interval [CI] 1.02-2.67) and better survival (hazard ratio [HR] 0.80, 95% CI 0.66-0.96). In 2016-2021, there were no differences in the odds of undergoing CRS-HIPEC between patients diagnosed in HIPEC centers versus referring centers (OR 1.27, 95% CI 0.76-2.13) and survival (HR 1.00, 95% CI 0.76-1.32). CONCLUSION: Previously observed differences in odds of undergoing CRS-HIPEC were no longer present. Increased awareness and the harmonization of treatment for PMCRC may have contributed to equal access to care and a similar chance of survival at a national level.

Systematic Cholecystectomy During Cytoreductive Surgery Plus HIPEC: A Critical Analysis of an Empirical Tradition.

BACKGROUND: Some procedures performed during cytoreductive surgery (CRS) and hyperthermic intraoperative intraperitoneal chemotherapy (HIPEC) are based on empirical data. One of these procedures is systematic cholecystectomy. This study aimed to perform a critical analysis of the need for systematic cholecystectomy during CRS+HIPEC of patients with peritoneal carcinomatosis using long-term follow-up data. METHODS: Patients with peritoneal surface malignancies who were candidates for CRS+HIPEC and underwent surgery between January 2008 and December 2022 were analyzed. For patients with gallbladder involvement due to the disease or for patients whose preoperative study showed the presence of cholelithiasis, cholecystectomy was performed as part of the surgery, which was avoided for the remaining patients. All postoperative adverse events that occurred in the first 90 days were recorded, and clinical records focused on the development of biliary pathology during the follow-up period were studied. RESULTS: The results from a consecutive series of 443 patients with peritoneal surface malignancies who underwent surgery between January 2008 and December 2022 were analyzed. The average age of the cohort was 50 years. The median follow-up period for the cohort was 41 months (range, 12-180 months), with a disease-free survival of 17 months. For 373 of the patients, CRS+HIPEC was completed without an associated cholecystectomy, and in 16 of them, the appearance of cholelithiasis was detected during the follow-up period. Only two patients in the series showed complications derived from gallstones and required a delayed cholecystectomy. CONCLUSIONS: Although cholecystectomy is a safe procedure in the context of CRS+HIPEC, it is not risk free, and its routine performance may be unnecessary.

Selective Gastrectomy with Knowledge of Gastric Anatomy and Blood Supply are Key to Complete Tumour Removal in Advanced Pseudomyxoma: Single-Centre Experience with 120 Gastrectomies Over 20 Years.

BACKGROUND: The role of gastrectomy to achieve complete cytoreduction (CCR) for pseudomyxoma peritonei (PMP) is controversial due to uncertain risk/benefit ratio. The outcomes of patients who gastrectomy over a twenty-year period in a high-volume unit are reported. METHODS: All patients requiring gastrectomy to achieve CCR for appendiceal PMP between 2000 and 2020 were reviewed. Demographics, disease, operative, complication, and survival data were analysed. The first and second decades were compared. RESULTS: A total of 2148 patients underwent CRS and HIPEC, of which 78% had CCR. Gastrectomy was performed in 7.1%. Median age was 55 years, and 52% were female. Among gastrectomy patients, 94.2% had ≥1 elevated tumour marker, and 18% had high-grade disease. Median PCI was 30, and 30% required subtotal colectomy. Clavien-Dindo III-IV complications occurred in 32%, and 90-day mortality was 1.75%. Median survival was 104 months, and 10-year OS was 47%. Comparing the two decades, total CRS cases almost tripled, with a greater proportion achieving CCR (82.2% vs. 67.8%) but fewer requiring gastrectomy (5.3% vs. 13.5%). In those who had gastrectomy, disease was more advanced (higher PCI, more high-grade disease, more colectomies) in the later period. However, on multivariable analysis, there was no difference in survival between decades. High-grade histology was the only predictor of survival. CONCLUSIONS: Gastrectomy can achieve good long-term survival with low mortality and acceptable morbidity and should not deter surgeons from achieving CCR. However, increasing experience shows CCR can be achieved, preserving the stomach in the majority of cases through careful consideration of the anatomy and gastric blood supply.

The 2022 PSOGI International Consensus on HIPEC Regimens for Peritoneal Malignancies: HIPEC Technologies.

This manuscript reports the results of an international consensus on technologies of hyperthermic intraperitoneal perioperative chemotherapy (HIPEC) performed with the following goals: To provide recommendations for the technological parameters to perform HIPEC. To identify the role of heat and its application forms in treating peritoneal metastases. To provide recommendations regarding the correct dosimetry of intraperitoneal chemotherapy drugs and their carrier solutions. To identify for each intraperitoneal chemotherapy regimen the best dosimetry and fractionation. To identify areas of future research pertaining to HIPEC technology and regimens. This consensus was performed by the Delphi technique and comprised two rounds of voting. In total, 96 of 102 eligible panelists replied to both Delphi rounds (94.1%) with a consensus of 39/51 questions on HIPEC technical aspects. Among the recommendations that met with the strongest consensus were those concerning the dose of HIPEC drug established in mg/m2, a target temperature of at least 42°C, and the use of at least three temperature probes to pursue hyperthermia. Ninety minutes as the ideal HIPEC duration seemed to make consensus. These results should be considered when designing new clinical trials in patients with peritoneal surface malignancies.

Intra- and Interpatient Drug Response Heterogeneity Exist in Patients Undergoing Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Nongynecologic Cancers.

BACKGROUND: Select patients with peritoneal metastases are treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). We assayed for intra- and interpatient drug response heterogeneity through testing of patient-derived tumor organoids (PDTOs). METHODS: PDTOs were generated from CRS/HIPEC patients from December 2021 to September 2022 and subjected to an in vitro HIPEC drug screen. Drug response was assessed with a cell viability assay and cleaved caspase-3 staining. RESULTS: A total of 31 patients were consented for tissue collection. Viable tissue was harvested from 23, and PDTO generation was successful in 13 (56%). PDTOs were analyzed from six appendiceal, three colorectal, two small bowel, one gastric, and one adrenal tumor. Drug screen results were generated in as few as 7 days (62%), with an average time of 12 days. Most patients received mitomycin-C (MMC) intraoperatively (n = 9); however, in only three cases was this agent considered the optimal choice in vitro. Three sets of PDTOs were resistant (defined as > 50% PDTO viability) to all agents tested and two were pan-sensitive (defined as 3 or more agents with < 50% PDTO viability). In three patients, organoids were generated from multiple metastatic sites and intrapatient drug response heterogeneity was observed. CONCLUSIONS: Both intra- and interpatient drug response heterogeneity exist in patients undergoing CRS/HIPEC for nongynecologic abdominal cancers. Caution must be used when interpreting patient response to chemotherapeutic agents based on a single site of testing in those with metastatic disease.

Metastatic Colorectal Cancer Treated with Combined Liver Resection, Cytoreductive Surgery, and Hyperthermic Intraperitoneal Chemotherapy (HIPEC): Predictive Factors for Early Recurrence.

BACKGROUND: Selection of colorectal cancer patients with concomitant peritoneal (PM) and liver metastases (LM) for radical treatment with cytoreductive surgery (CRS), including liver resection and hyperthermic intraperitoneal chemotherapy (HIPEC), needs improvement. This retrospective, monocentric study was designed to evaluate the predictive factors for early recurrence, disease-free survival (DFS), and overall survival (OS) in such patients treated in a referral center. METHODS: Consecutive colorectal cancer patients with concomitant LM and PM treated with curative intent with perioperative systemic chemotherapy, simultaneous complete CRS, liver resection, and HIPEC in 2011-2022 were included. Clinical, radiological (before and after preoperative chemotherapy), surgical, and pathological data were investigated, along with long-term oncologic outcomes. A multivariate analysis was performed to identify predictive factors associated with early recurrence (diagnosed <6 months after surgery), DFS, and OS. RESULTS: Of more than 61 patients included, 31 (47.1%) had pT4 and 27 (40.9%) had pN2 primary tumors. Before preoperative chemotherapy, the median number of LM was 2 (1-4). The median surgical PCI (peritoneal carcinomatosis index) was 3 (5-8.5). The median DFS and OS were 8.15 (95% confidence interval [CI] 5.5-10.1) and 34.1 months (95% CI 28.1-53.5), respectively. In multivariate analysis, pT4 (odds ratio [OR] = 4.14 [1.2-16.78], p = 0.032]) and pN2 (OR = 3.7 [1.08-13.86], p = 0.042) status were independently associated with an early recurrence, whereas retroperitoneal lymph node metastasis (hazard ratio [HR] = 39 [8.67-175.44], p < 0.001) was independently associated with poor OS. CONCLUSIONS: In colorectal cancer patients with concomitant PM and LM, an advanced primary tumor (pT4 and/or pN2) was associated with a higher risk of early recurrence following a radical multimodal treatment, whereas RLN metastases was strongly detrimental for OS.

2022 Peritoneal Surface Oncology Group International Consensus on HIPEC Regimens for Peritoneal Malignancies: Colorectal Cancer.

BACKGROUND: Selected patients with peritoneal metastases of colorectal cancer (PM-CRC) can benefit from potentially curative cytoreductive surgery (CRS) ± hyperthermic intraperitoneal chemotherapy (HIPEC), with a median overall survival (OS) of more than 40 months. OBJECTIVE: The aims of this evidence-based consensus were to define the indications for HIPEC, to select the preferred HIPEC regimens, and to define research priorities regarding the use of HIPEC for PM-CRC. METHODS: The consensus steering committee elaborated and formulated pertinent clinical questions according to the PICO (patient, intervention, comparator, outcome) method and assessed the evidence according to the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) framework. Standardized evidence tables were presented to an international expert panel to reach a consensus (4-point, weak and strong positive/negative) on HIPEC regimens and research priorities through a two-round Delphi process. The consensus was defined as ≥ 50% agreement for the 4-point consensus grading or ≥ 70% for either of the two combinations. RESULTS: Evidence was weak or very weak for 9/10 clinical questions. In total, 70/90 eligible panelists replied to both Delphi rounds (78%), with a consensus for 10/10 questions on HIPEC regimens. There was strong negative consensus concerning the short duration, high-dose oxaliplatin (OX) protocol (55.7%), and a weak positive vote (53.8-64.3%) in favor of mitomycin-C (MMC)-based HIPEC (preferred choice: Dutch protocol: 35 mg/m2, 90 min, three fractions), both for primary cytoreduction and recurrence. Determining the role of HIPEC after CRS was considered the most important research question, regarded as essential by 85.7% of the panelists. Furthermore, over 90% of experts suggest performing HIPEC after primary and secondary CRS for recurrence > 1 year after the index surgery. CONCLUSIONS: Based on the available evidence, despite the negative results of PRODIGE 7, HIPEC could be conditionally recommended to patients with PM-CRC after CRS. While more preclinical and clinical data are eagerly awaited to harmonize the procedure further, the MMC-based Dutch protocol remains the preferred regimen after primary and secondary CRS.

Retrospective Evaluation of the Prognostic Value of Histological Growth Pattern in Patients with Colorectal Peritoneal Metastases Undergoing Curative-Intent Cytoreductive Surgery.

BACKGROUND: Two distinct histological growth patterns (HGPs) were described in patients with peritoneal metastasis of colorectal cancer origin (PMCRC) with limited Peritoneal Cancer Index (PCI) ≤ 6 who did not receive neoadjuvant chemotherapy (NAC) and were treated with cytoreductive surgery (CRS) ± hyperthermic intraperitoneal chemotherapy (HIPEC): pushing HGP (P-HGP) and infiltrating HGP (I-HGP). Patients with dominant P-HGP (> 50%) had significantly better disease-free survival (DFS) and overall survival (OS). OBJECTIVE: We aimed to determine whether these previous observations regarding the prognostic value of HGP in patients with PMCRC with low PCI (≤ 6) are also valid in all operable patients, regardless of whether they received NAC or not and regardless of PCI score. METHODS: This was a retrospective study including 76 patients who underwent complete CRS ± HIPEC for PMCRC between July 2012 and March 2019. In each patient, up to five of the largest excised peritoneal nodules were analyzed for their tumor-to-peritoneum interface. Correlations between NAC, HGP, and prognosis were further explored. RESULTS: Thirty-seven patients (49%) had dominant P-HGP and 39 (51%) had dominant I-HGP. On univariate analysis, patients with P-HGP ≤ 50% had significantly lower OS than those with dominant P-HGP > 50% (39 versus 60 months; p = 0.014) confirmed on multivariate analysis (hazard ratio 2.4, 95% confidence interval 1.3-4.5; p = 0.006). There were no significant associations between NAC and type of HGP. CONCLUSIONS: This study confirms the prognostic value and reproducibility of the two previously reported HGPs in PMCRC. Dominant P-HGP is associated with better DFS and OS in patients undergoing curative-intent CRS ± HIPEC compared with I-HGP, independently of the extent of peritoneal disease burden.

Home-Based Trimodal Prehabilitation in Patients with Peritoneal Carcinomatosis Undergoing Cytoreductive Surgery: Effect on Functional Walking Capacity and Skeletal Muscle Mass.

BACKGROUND: Patients with peritoneal carcinomatosis often suffer from loss of skeletal muscle mass and require extensive surgery. Multimodal prehabilitation may improve physical status but its benefits for these specific patients remain unknown. This study aimed to evaluate the effect of prehabilitation on functional walking capacity and skeletal muscle mass, as well as its association with postoperative complications. PATIENTS AND METHODS: A prospective study of patients with peritoneal carcinomatosis following a home-based trimodal prehabilitation program was carried out. Functional walking capacity was assessed with the 6-min walk test (T6MWT), and by the appendicular skeletal muscle index (ASMI) estimated by bioelectrical impedance analysis. Data were collected at the first medical appointment and on the day before surgery. A 90-day postoperative morbidity was registered according to the Clavien-Dindo classification. RESULTS: A total of 62 patients were included in the analysis. Women were more prevalent (77.4%) and peritoneal metastasis from ovarian origin accounted for 48.4%. Clavien II-V grades occurred in 30 (57.7%) patients. After prehabilitation, functional walking capacity improved by 42.2 m (39.62-44.72 m) compared with baseline data (p < 0.001), but no improvement was observed in the ASMI (p = 0.301). Patients able to walk at least 360 m after prehabilitation suffered fewer Clavien-Dindo II-V postoperative complications (p = 0.016). A T6MWT of less than 360 m was identified as an independent risk factor in the multivariable analysis (OR 3.99; 1.01-15.79 p = 0.048). CONCLUSIONS: This home-based trimodal prehabilitation program improved functional walking capacity but not ASMI scores in patients with peritoneal metastasis before surgery. A T6MWT of less than 360 m was found to be a risk factor for postoperative complications.

Survival Analysis and Recurrence Patterns in 555 Patients with Colorectal Peritoneal Metastases Treated by Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy.

BACKGROUND: The presence at diagnosis, or development of, colorectal peritoneal metastases (CPM) is common in colorectal cancer. Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) show promising results in selected patients with CPM. The current study aimed to describe oncologic outcomes of patients with CPM, focusing on recurrence patterns and risk factors for adverse events. METHODS: We conducted a retrospective review of patients with CPM treated by CRS and HIPEC at a single institution between 2000 and 2021. RESULTS: A total of 555 patients were included, of whom 480 (86.5%) had complete cytoreduction, with a median age of 59 years and median Peritoneal Cancer Index (PCI) of 6. Following complete cytoreduction, 5-year overall survival (OS) and disease-free survival (DFS) were 51% and 31%, respectively. In multivariable Cox regression, PCI >6 (hazard ratio [HR] 2.25), pathological node positivity (pN+; HR 1.94), and perineural invasion (HR 1.85) were associated with decreased OS, while PCI >6, pN+, and previous systemic metastases resulted in reduced DFS. Overall, 284 (62%) patients developed recurrence, of whom 97 (34%) had local recurrence (LR), 100 (35%) had systemic recurrence (SR), and 87 (31%) had combined recurrence (5-year OS: 49.3%, 46%, and 37.4%, respectively). Mutated KRAS (mKRAS) was associated with lower 5-year OS (55.8%) and DFS (27.9%) compared with wild-type KRAS (wtKRAS; 70.7% and 37.6%, respectively). In multivariable analyses, mKRAS was related to decreased OS (HR 1.82), DFS (HR 1.55), and SR (OS 1.89), but not to LR. CONCLUSIONS: Complete cytoreduction results in good survival outcomes for patients with CPM. Burden of peritoneal disease and tumor biology are the main predictors of survival. Patients with mKRAS are a high-risk cohort, with increased probability of SR and reduced survival.

Predictive Value of C-Reactive Protein for Infectious Complications After Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy: A Single-Center Prospective Study.

BACKGROUND: Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) can be associated with significant morbidity and prolonged hospital stay. Postoperative infections account for a high burden of these complications. This study aimed to assess the predictive value of postoperative C-reactive protein (CRP) levels for overall infectious complications and anastomotic leaks. METHODS: This was a single-center prospective study of patients undergoing CRS and HIPEC for peritoneal metastases between 2018 and 2020 at Maisonneuve-Rosemont Hospital in Montreal, QC, Canada. CRP levels were measured daily for 10 days following surgery. A comparison was made between patients with infectious complications and those without. RESULTS: Ninety-nine patients were included. Thirty patients had infectious complications (30.3%) and four patients presented an anastomotic leak (4%). CRP levels were significantly higher in patients with infectious complications from postoperative days (PODs) 2-10. Daily cut-off values most accurately predicted infectious complications on day 8 (94.3 mg/L; area under the curve [AUC] 0.85, sensitivity [SE] 76.2%, specificity [SP] 94.7%, positive predictive value [PPV] 88.9%, negative predictive value [NPV] 87.8%; p < 0.0001) and day 9 (72.7 mg/L; AUC 0.89, SE 95.2%, SP 81.8%, PPV 76.9%, NPV 96.4%; p < 0.0001). Patients with infectious complications had longer operative time, higher peritoneal cancer index, and a higher number of intestinal anastomoses, while their baseline characteristics were comparable. CONCLUSION: Measurement of CRP helps predict infectious complications following CRS and HIPEC, particularly on PODs 8 and 9. Cut-off values are more accurate after the first postoperative week, especially in ruling out infectious complications.

Should Cytoreductive Surgery Alone for Peritoneal Metastases of Colorectal Origin be Centralized? A National Study of 4159 Procedures.

BACKGROUND: Addition of oxaliplatin-based hyperthermic intraperitoneal chemotherapy (HIPEC) to cytoreductive surgery (CRS) in the treatment of peritoneal metastases of colorectal origin (CRPM) did not show any survival benefit in the PRODIGE 7 trial (P7). This study aimed to investigate whether perioperative outcomes after CRS alone for CRPM patients is mediated by hospital volume and to determine the effect of P7 on French practice for CRPM patients treated respectively with CRS alone and CRS/HIPEC. METHODS: Data from CRPM patients treated with CRS alone between 2013 and 2020 in France were collected through a national medical database. The study used a cutoff value of the annual CRS-alone caseload affecting the 90-day postoperative mortality (POM) determined from our previous study to define low-volume (LV) HIPEC and high-volume (HV) HIPEC centers. Perioperative outcomes were compared between no-HIPEC, LV-HIPEC, and HV-HIPEC centers. The trend between years and HIPEC rates was analyzed using the Cochrane-Armitage test. RESULTS: Data from 4159 procedures were analyzed. The patients treated in no-HIPEC and LV-HIPEC centers were older compared with HV-HIPEC centers (p < 0.0001) and had a higher Elixhauser comorbidity index (p < 0.0001) and less complex surgery (p < 0.0001). Whereas the major morbidity (MM) rate did not differ between groups (p = 0.79), the 90-day POM was lower in HV-HIPEC centers than in no-HIPEC and LV-HIPEC centers (5.4% vs 15% and 13.3%; p < 0.0001), with lower failure-to-rescue (FTR) (p < 0.0001). After P7, the CRS/HIPEC rate decreased drastically in Cancer centers (p < 0.001), whereas patients treated with CRS alone are still referred to expert centers. CONCLUSIONS: Centralization of CRS alone should improve patient selection as well as FTR and POM. After P7, CRS/HIPEC decreased mostly in Cancer centers, without any impact on the number of CRS-alone cases referred to expert centers.

Improved Postoperative Pain Management Outcomes After Implementation of Enhanced Recovery After Surgery (ERAS) Protocol for Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy (CRS-HIPEC).

BACKGROUND: Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) for patients with peritoneal carcinomatosis is promising but has potential for significant morbidity and prolonged hospitalization. Enhanced Recovery After Surgery (ERAS) is a standardized protocol designed to optimize perioperative care. This study describes trends in epidural and opioid use after implementing ERAS for CRS-HIPEC at a tertiary academic center. METHODS: A retrospective analysis of patients undergoing CRS-HIPEC from January 2020 to September 2023 was conducted. ERAS was implemented in February 2022. Medication and outcomes data were compared before and after ERAS initiation. All opioids were converted to morphine milligram equivalents (MMEs). RESULTS: A total of 136 patients underwent CRS-HIPEC: 73 (54%) pre- and 63 (46%) post-ERAS. Epidural usage increased from 63% pre-ERAS to 87% post-ERAS (p = 0.001). Compared with those without epidurals, patients with epidurals had decreased total 7-day oral and intravenous (IV) opioid requirements (45 MME vs. 316 MME; p < 0.001). There was no difference in 7-day opioid totals between pre- and post-ERAS groups. After ERAS, more patients achieved early ambulation (83% vs. 53%; p < 0.001), early diet initiation (81% vs. 25%; p < 0.001), and early return of bowel function (86% vs. 67%; p = 0.012). CONCLUSIONS: ERAS implementation for CRS-HIPEC was associated with increased epidural use, decreased oral and IV opioid use, and earlier bowel function return. Our study demonstrates that epidural analgesia provides adequate pain control while significantly decreasing oral and IV opioid use, which may promote gastrointestinal recovery postoperatively. These findings support the implementation of an ERAS protocol for effective pain management in patients undergoing CRS-HIPEC.

Assessment of Intraoperative Scoring Systems for Predicting Cytoreduction Outcome in Peritoneal Metastatic Disease: A Systematic Review and Meta-analysis.

BACKGROUND: Cytoreductive surgery (CRS) is a widely acknowledged treatment approach for peritoneal metastasis, showing favorable prognosis and long-term survival. Intraoperative scoring systems quantify tumoral burden before CRS and may predict complete cytoreduction (CC). This study reviews the intraoperative scoring systems for predicting CC and optimal cytoreduction (OC) and evaluates the predictive performance of the Peritoneal Cancer Index (PCI) and Predictive Index Value (PIV). METHODS: Systematic searches were conducted in Embase, MEDLINE, and Web of Science. Meta-analyses of extracted data were performed to compare the absolute predictive performances of PCI and PIV. RESULTS: Thirty-eight studies (5834 patients) focusing on gynecological (n = 34; 89.5%), gastrointestinal (n = 2; 5.3%) malignancies, and on tumors of various origins (n = 2; 5.3%) were identified. Seventy-seven models assessing the predictive performance of scoring systems (54 for CC and 23 for OC) were identified with PCI (n = 39/77) and PIV (n = 16/77) being the most common. Twenty models (26.0%) reinterpreted previous scoring systems of which ten (13%) used a modified version of PIV (reclassification). Meta-analyses of models predicting CC based on PCI (n = 21) and PIV (n = 8) provided an AUC estimate of 0.83 (95% confidence interval [CI] 0.79-0.86; Q = 119.6, p = 0.0001; I2 = 74.1%) and 0.74 (95% CI 0.68-0.81; Q = 7.2, p = 0.41; I2 = 11.0%), respectively. CONCLUSIONS: Peritoneal Cancer Index models demonstrate an excellent estimate of CC, while PIV shows an acceptable performance. There is a need for high-quality studies to address management differences, establish standardized cutoff values, and focus on non-gynecological malignancies.

Evaluating nutrition in advanced ovarian cancer: which biomarker works best?

BACKGROUND: Advanced epithelial ovarian cancer (OC) patients often present with malnutrition; however, the ideal nutritional evaluation tool is unclear. We aimed to evaluate the role of preoperative albumin, Prognostic Nutritional Index [PNI], neutrophil-to-lymphocyte ratio [NLR], and platelet-to-lymphocyte ratio [PLR] as independent predictors of severe postoperative complications and 90-day mortality in OC patients who underwent primary cytoreductive surgery to identify the ideal tool. METHODS: OC patients who underwent surgery at Mayo Clinic (2003-2018) were included; biomarkers were retrospectively retrieved and established cut-offs were utilized. Outcomes included severe complications (Accordion grade ≥ 3) and 90-day mortality. Univariate and multivariable logistic regression models were performed. Biomarkers were evaluated in separate models adjusted for age and American Society of Anesthesiologists (ASA) score for 90-day mortality, and adjusted for age, ASA score, stage, and surgical complexity for severe complications. RESULTS: Albumin <3.5 g/dL, PNI < 45, NLR > 6 and PLR ≥ 200 were univariately associated with 90-day mortality (all p < 0.05) in 627 patients that met inclusion criteria. Each marker remained significant in adjusted models with albumin having the highest OR: 6.04 [95% CI:2.80-13.03] and AUC (0.83). Univariately, PNI <45, NLR >6, and PLR ≥200 were significant predictors of severe complications(all p < 0.05), however failed to reach significance in adjusted models. Albumin was not associated with severe complications. CONCLUSION: All biomarkers were associated with 90-day mortality in adjusted models, with albumin being the easiest predictor to attain clinically; none with severe complications. Future research should focus less on methods of nutritional assessment and more on strategies to improve nutrition during OC tumor-directed therapy.

Comparing survival of older ovarian cancer patients treated with neoadjuvant chemotherapy versus primary cytoreductive surgery: Reducing bias through machine learning.

OBJECTIVE: To develop and evaluate a multidimensional comorbidity index (MCI) that identifies ovarian cancer patients at risk of early mortality more accurately than the Charlson Comorbidity Index (CCI) for use in health services research. METHODS: We utilized SEER-Medicare data to identify patients with stage IIIC and IV ovarian cancer, diagnosed in 2010-2015. We employed partial least squares regression, a supervised machine learning algorithm, to develop the MCI by extracting latent factors that optimally captured the variation in health insurance claims made in the year preceding cancer diagnosis, and 1-year mortality. We assessed the discrimination and calibration of the MCI for 1-year mortality and compared its performance to the commonly-used CCI. Finally, we evaluated the MCI's ability to reduce confounding in the association of neoadjuvant chemotherapy (NACT) and all-cause mortality. RESULTS: We included 4723 patients in the development cohort and 933 in the validation cohort. The MCI demonstrated good discrimination for 1-year mortality (c-index: 0.75, 95% CI: 0.72-0.79), while the CCI had poor discrimination (c-index: 0.59, 95% CI: 0.56-0.63). Calibration plots showed better agreement between predicted and observed 1-year mortality risk for the MCI compared with CCI. When comparing all-cause mortality between NACT with primary cytoreductive surgery, NACT was associated with a higher hazard of death (HR: 1.13, 95% CI: 1.04-1.23) after controlling for tumor characteristics, demographic factors, and the CCI. However, when controlling for the MCI instead of the CCI, there was no longer a significant difference (HR: 1.05, 95% CI: 0.96-1.14). CONCLUSIONS: The MCI outperformed the conventional CCI in predicting 1-year mortality, and reducing confounding due to differences in baseline health status in comparative effectiveness analysis of NACT versus primary surgery.