Ninety percent of the adverse outcomes occur in 10% of patients: can we identify the populations at high risk of developing peritoneal metastases after curative surgery for colorectal cancer?

The Role of Prophylactic or Adjuvant Hyperthermic Intraperitoneal Therapy in Appendiceal and Colorectal Cancer Peritoneal Metastasis

Appendiceal neoplasms and colorectal cancer have a propensity to develop peritoneal metastases. Despite advancements in systemic therapy and surgical management, the development and management of peritoneal metastases remains a challenging problem. Utilization of adjuvant or prophylactic hyperthermic intraperitoneal chemotherapy has been described, with varying quality of data and reported outcomes. The utilization of prophylactic or adjuvant hyperthermic intraperitoneal chemotherapy in patients with appendiceal neoplasms and colorectal cancer remains an active area of exploration.

Risk of metachronous peritoneal metastases after surgery for obstructive colon cancer: Multivariate analysis from a series of 1,085 patients

BACKGROUND

Data in the literature suggest that obstruction is an independent predictor of poor prognosis in colon cancer. Of all possible sites of recurrence, peritoneal metastases are associated with worse survival. Our aim was to report the incidence of metachronous peritoneal metastases from a cohort of patients undergoing resection of obstructive colon cancer with curative intent and to identify predictive factors for metachronous peritoneal metastases.

METHODS

From 2000 to 2015, a total of 2,325 patients were treated for obstructive colon cancer in French surgical centers, members of the French National Surgical Association (AFC). Patients with palliative management, synchronous metastatic disease, and with postoperative mortality were excluded. A multivariate analysis was performed to determine independent predictive factors of metachronous peritoneal metastases.

RESULTS

The cohort included 1,085 patients. The median follow-up was 21.5 months. Metachronous peritoneal metastases occurred in 12% of patients and were diagnosed after a median interval of 13.5 months. The cumulative 3-year metachronous peritoneal metastasis rate was 10.9%. Three-year overall survival was 85% for patients who did not develop recurrence, 71% for those who develop recurrence without peritoneal metastases, and 56% for those with metachronous peritoneal metastases (P < .0001). In multivariate analysis, 3 variables were identified as independent risk factors for metachronous peritoneal metastases: pT4 stage (odds ratio: 1.98; 95% confidence interval: 1.17-3.36; P = .011), pN2 stage (odds ratio: 2.57; 95% confidence interval: 1.89-4.45; P = .0007), and fewer than 12 lymph nodes examined (odds ratio: 2.01; 95% confidence interval: 1.08-3.74; P = .028).

CONCLUSION

This study showed a significant risk of metachronous peritoneal metastases after curative-intent resection of obstructive colon cancer. The awareness of factors predisposing to metachronous peritoneal metastases could improve the treatment strategy of these patients.

Predictive Factors for Peritoneal Metastases in Colorectal Cancer: A Retrospective Study Conducted at a Tertiary Care Center in Riyadh, Saudi Arabia

Background The incidence of colorectal cancer (CRC) is increasing nationally, emphasizing the importance of early detection. Late-stage diagnosis, particularly with peritoneal metastasis (PM), is associated with poor outcomes despite advancements in treatment. PM poses a challenge owing to the lack of standardized treatment, although cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) shows promise in improving survival rates. This study aimed to document the incidence and risk factors for patients presenting with PM following CRC. Materials and methods This retrospective chart review study was conducted at King Abdulaziz Medical City in Saudi Arabia. Patients of all ages and genders who underwent surgical resection for CRC from January 2016 to December 2021 were included. Patients with PM at primary index surgery, distant organ metastasis to the lung or liver, or other types of cancer were excluded. The data was analyzed via SPSS Statistics version 27.0 (IBM Corp. Released 2020. IBM SPSS Statistics for Windows, Version 27.0. Armonk, NY: IBM Corp.), t-test, Wilcoxon rank-sum test, chi-square test, and Fisher's exact tests. Results Among 565 patients with CRC, 65 patients (11.5%) developed PM. Tumor characteristics such as T4 stage, mucinous tumors, elevated CEA, and the presence of ovarian metastasis at primary resection were independent factors for peritoneal recurrence. However, in univariate and multivariate associations, the presence of ovarian metastasis, mucinous tumors, postoperative CEA levels exceeding 5 ng/ml, and perforation are significant risk factors for PM development post-surgery, with hazard ratios of 6.457 (CI 2.481-16.801) and 4.057 (2.029-8.115), respectively. Conclusion Mucinous tumors and ovarian metastasis are significant risk factors for PM development, emphasizing the importance of early identification for tailored treatment strategies such as CRS and HIPEC.

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.

Peritoneal Metastasis: A Dilemma and Challenge in the Treatment of Metastatic Colorectal Cancer

Peritoneal metastasis (PM) is a common mode of distant metastasis in colorectal cancer (CRC) and has a poorer prognosis compared to other metastatic sites. The formation of PM foci depends on the synergistic effect of multiple molecules and the modulation of various components of the tumor microenvironment. The current treatment of CRC-PM is based on systemic chemotherapy. However, recent developments in local therapeutic modalities, such as cytoreductive surgery (CRS) and intraperitoneal chemotherapy (IPC), have improved the survival of these patients. This article reviews the research progress on the mechanism, characteristics, diagnosis, and treatment strategies of CRC-PM, and discusses the current challenges, so as to deepen the understanding of CRC-PM among clinicians.

Epidemiology, oncologic results and risk stratification model for metachronous peritoneal metastases after surgery for pT4 colon cancers: results from an observational retrospective multicentre long-term follow-up study

PURPOSE

Metachronous peritoneal metastases (MPM) following a curative surgery procedure for pT4 colon cancer is a challenging condition. Current epidemiological studies on this topic are scarce.

METHODS

A retrospective multicentre trial was designed. All consecutive patients who underwent operations to treat pT4 cancers between 2015 and 2017 were reviewed. Demographic, clinical, operative, pathological and oncological follow-up variables were included. MPM were described as any oncological disease at the peritoneum, clearly different from a local recurrence. Univariate and multivariate Cox regression models were constructed. A risk stratification model was created on a cumulative factor basis. According to the calculated hazard ratio (HR), a scoring system was designed (HR < 3, 1 point; HR > 3, 2 points) and a scale from 0 to 6 was calculated for peritoneal disease-free rate (PDF-R). A risk stratification model was also created on the basis of these calculations.

RESULTS

Fifty different hospitals were involved, which included a total of 1356 patients. Incidence of MPM was 13.6% at 50 months median follow-up. The strongest independent risk factors for MPM were positive pN stage [HR 3.72 (95% CI 2.56-5.41; p < 0.01) for stage III disease], tumour perforation [HR 1.91 (95% CI 1.26-2.87; p < 0.01)], mucinous or signet ring cell histology [HR 1.68 (95% CI 1.1-2.58; p = 0.02)], poorly differentiated tumours [HR 1.54 (95% CI 1.1-2.2; p = 0.02)] and emergency surgery [HR 1.42 (95% CI 1.01-2.01; p = 0.049)]. In the absence of additional risk factors, pT4 tumours showed 98% and 96% PDF-R in 1-year and 5-year periods based on Kaplan-Meier curves.

CONCLUSIONS

Cumulative MPM incidence was 13.6% at 5-year follow-up. The sole presence of a pT4 tumour resulted in high rates of PDF-R at 1-year and 5-year follow-up (98% and 96% respectively). Five additional risk factors different from pT4 status itself were identified as possible MPM indicators during follow-up.

The Role of Prophylactic and Adjuvant Hyperthermic Intraperitoneal Chemotherapy (HIPEC) in Prevention of Peritoneal Metastases in Advanced Colorectal Cancer

Hyperthermic intraperitoneal chemotherapy (HIPEC) is a locoregional therapy that may be combined with cytoreductive surgery (CRS) to treat patients with colorectal cancer and peritoneal metastases (PM). In recent years, three randomized controlled trials (RCTs) have investigated the role of prophylactic or adjuvant HIPEC in preventing the development of PM in patients with high-risk colorectal cancer: PROPHYLOCHIP and COLOPEC evaluated adjuvant HIPEC, and HIPECT4 studied concurrent HIPEC and CRS. Although PROPHYLOCHIP and COLOPEC were negative trials, a great deal may be learned from their methodology, outcome measures, and patient selection criteria. HIPECT4 is the first RCT to show a clinical benefit of HIPEC in high-risk T4 colorectal cancer, demonstrating improved locoregional disease control with the addition of HIPEC to CRS with no increase in the rate of complications. This review critically examines the strengths and limitations of each major trial and discusses their potential impact on the practice of HIPEC. Several additional ongoing clinical trials also seek to investigate the role of HIPEC in preventing PM in advanced colorectal cancer.

Risk factors for metachronous peritoneal carcinomatosis after radical resection for patients with nonmetastatic pT3-4 colon cancer

BACKGROUND

Patients with nonmetastatic pT3-4 colon cancers are prone to develop metachronous peritoneal carcinomatosis (mPC). Risk factors for mPC and the influence of mutant kirsten rat sarcoma viral oncogene (KRAS)/neuroblastoma rat sarcoma (NRAS)/v-raf murine sarcoma viral oncogene homolog B1 (BRAF) and DNA mismatch repair (MMR) status on mPC remain to be described in these patients.

METHOD

All enrolled patients were identified from the prospectively collected colorectal cancer database of a tertiary referral hospital between 2013 and 2018. Multivariate analysis was used to identify risk factors associated with mPC.

RESULTS

Of the 1689 patients with nonmetastatic pT3-4 colon carcinoma, 8.4% (142/1689) progressed to mPC. Endoscopic obstruction (HR = 3.044, p < 0.001), elevated CA125 (HR = 1.795, p = 0.009), pT (T4a vs. T3, HR = 2.745, p < 0.001; T4b vs. T3, HR = 3.167, p = 0.001), pN (N1 vs. N0, HR = 2.592, p < 0.001; N2 vs. N0, HR = 4.049, p < 0.001), less than 12 lymph nodes harvested (HR = 2.588, p < 0.001), mucinous or signet ring cell carcinoma (HR = 1.648, p = 0.038), perineural invasion (HR = 1.984, p < 0.001), and adjuvant chemotherapy (HR = 1.522, p = 0.039) were strongly related to mPC but that mutant KRAS/NRAS/BRAF and MMR status was not associated with mPC.

CONCLUSION

This study identified the high-risk factors for mPC in patients with nonmetastatic pT3-4 colon carcinoma, and these factors should be considered in selective preventive therapy and close follow-up for patients subsequently deemed to have high risk for mPC.

Primary and metastatic peritoneal surface malignancies

Peritoneal surface malignancies comprise a heterogeneous group of primary tumours, including peritoneal mesothelioma, and peritoneal metastases of other tumours, including ovarian, gastric, colorectal, appendicular or pancreatic cancers. The pathophysiology of peritoneal malignancy is complex and not fully understood. The two main hypotheses are the transformation of mesothelial cells (peritoneal primary tumour) and shedding of cells from a primary tumour with implantation of cells in the peritoneal cavity (peritoneal metastasis). Diagnosis is challenging and often requires modern imaging and interventional techniques, including surgical exploration. In the past decade, new treatments and multimodal strategies helped to improve patient survival and quality of life and the premise that peritoneal malignancies are fatal diseases has been dismissed as management strategies, including complete cytoreductive surgery embedded in perioperative systemic chemotherapy, can provide cure in selected patients. Furthermore, intraperitoneal chemotherapy has become an important part of combination treatments. Improving locoregional treatment delivery to enhance penetration to tumour nodules and reduce systemic uptake is one of the most active research areas. The current main challenges involve not only offering the best treatment option and developing intraperitoneal therapies that are equivalent to current systemic therapies but also defining the optimal treatment sequence according to primary tumour, disease extent and patient preferences. New imaging modalities, less invasive surgery, nanomedicines and targeted therapies are the basis for a new era of intraperitoneal therapy and are beginning to show encouraging outcomes.

Risk factors for developing peritoneal metastases after curative surgery for colorectal cancer: A systematic review and meta-analysis

AIM

Proactive detection and treatment strategies have achieved encouraging survival outcomes for patients with early peritoneal metastases (PM), but these costly and invasive approaches can only be applied to selected high-risk patients. This meta-analysis aimed to identify the risk factors for metachronous PM after curative surgery for colorectal cancer (CRC).

METHOD

The study was registered at PROSPERO (CRD42020219187). Databases were searched for studies comparing clinical and histopathological characteristics between patients with metachronous peritoneal metastases from colorectal cancer (pmCRC) and patients without (non-pmCRC).

RESULTS

Thirty-six studies were included. Metachronous PM were positively associated with perforation (OR 1.920; 95% CI 1.144-3.223; P = 0.014), poor differentiation (OR 2.291; 1.603-3.275; P < 0.001), T4 (OR 2.897; 1.248-6.726; P = 0.013), N1-2 (OR 3.429; 2.684-4.381; P < 0.001), mucinous adenocarcinoma (OR 4.175; 1.798-9.692; P = 0.001), obstruction (OR 4.467; 1.919-10.398; P = 0.001), synchronous ovarian metastases (OR 5.005; 1.140-21.977; P = 0.033), positive peritoneal carcinoembryonic antigen mRNA (OR 9.472; 3.643-24.631; P < 0.001), elevated serum carcinoembryonic antigen (preoperative group, OR 3.545, 1.486-8.459, P = 0.004; postoperative group, OR 13.673, 2.222-84.129, P = 0.005), elevated serum cancer antigen 19-9 (preoperative group, OR 5.281, 2.146-12.994, P < 0.001; postoperative group, OR 18.646, 6.429-54.083, P < 0.001) and positive peritoneal cytology (OR 25.884; 11.372-58.913; P < 0.001).

CONCLUSION

These evidence-based risk factors are conducive to designing early detection and proactive treatment strategies, enabling precision medicine.

HIPEC Methodology and Regimens: The Need for an Expert Consensus

BACKGROUND

Hyperthermic intraperitoneal chemotherapy (HIPEC) is performed with a wide variation in methodology, drugs, and other elements vital to the procedure. Adoption of a limited number of regimens could increase the collective experience of peritoneal oncologists, make comparison between studies more meaningful, and lead to a greater acceptance of results from randomized trials. This study aimed to determine the possibility of standardizing HIPEC methodology and regimens and to identify the best method of performing such a standardization.

METHODS

A critical review of preclinical and clinical studies evaluating the pharmacokinetic aspects of different HIPEC drugs and drug regimens, the impact of hyperthermia, and the efficacy of various HIPEC regimens as well as studies comparing different regimens was performed.

RESULTS

The preclinical and clinical data were limited, and studies comparing different regimens were scarce. Many of the regimens were neither supported by preclinical rationale or data nor validated by a dose-escalating formal phase 1 trial. All the regimens were based on pharmacokinetic data and did not take chemosensitivity of peritoneal metastases into account. Personalized medicine approaches such as patient-derived tumor organoids could offer a solution to this problem, although clinical validation is likely to be challenging.

CONCLUSIONS

Apart from randomized trials, more translational research and phases 1 and 2 studies are needed. While waiting for better preclinical and clinical evidence, the best way to minimize heterogeneity is by an expert consensus that aims to identify and define a limited number of regimens for each indication and primary site. The choice of regimen then can be tailored to the patient profile and its expected toxicity and the methodology according regional factors.

Peritoneal Metastases From Colorectal Cancer: Defining and Addressing the Challenges

The presence of peritoneal metastases (PM) in patients with colorectal cancer (CRC) is associated with an extremely poor prognosis. The diagnosis of PM is challenging, resulting in an underestimation of their true incidence. While surgery can be curative in a small percentage of patients, effective treatment for non-operable PM is lacking, and clinical and pre-clinical studies are relatively sparse. Here we have defined the major clinical challenges in the areas of risk assessment, detection, and treatment. Recent developments in the field include the application of organoid technology, which has generated highly relevant pre-clinical PM models, the application of diffusion-weighted MRI, which has greatly improved PM detection, and the design of small clinical proof-of-concept studies, which allows the efficient testing of new treatment strategies. Together, these developments set the stage for starting to address the clinical challenges. To help structure these efforts, a translational research framework is presented, in which clinical trial design is based on the insight gained from direct tissue analyses and pre-clinical (organoid) models derived from CRC patients with PM. This feed-forward approach, in which a thorough understanding of the disease drives innovation in its clinical management, has the potential to improve outcome in the years to come.

Second-look surgery plus hyperthermic intraperitoneal chemotherapy versus surveillance in patients at high risk of developing colorectal peritoneal metastases (PROPHYLOCHIP-PRODIGE 15): a randomised, phase 3 study

BACKGROUND

Diagnosis and treatment of colorectal peritoneal metastases at an early stage, before the onset of signs, could improve patient survival. We aimed to compare the survival benefit of systematic second-look surgery plus hyperthermic intraperitoneal chemotherapy (HIPEC), with surveillance, in patients at high risk of developing colorectal peritoneal metastases.

METHODS

We did an open-label, randomised, phase 3 study in 23 hospitals in France. Eligible patients were aged 18-70 years and had a primary colorectal cancer with synchronous and localised colorectal peritoneal metastases removed during tumour resection, resected ovarian metastases, or a perforated tumour. Patients were randomly assigned (1:1) to surveillance or second-look surgery plus oxaliplatin-HIPEC (oxaliplatin 460 mg/m², or oxaliplatin 300 mg/m² plus irinotecan 200 mg/m², plus intravenous fluorouracil 400 mg/m²), or mitomycin-HIPEC (mitomycin 35 mg/m²) alone in case of neuropathy, after 6 months of adjuvant systemic chemotherapy with no signs of disease recurrence. Randomisation was done via a web-based system, with stratification by treatment centre, nodal status, and risk factors for colorectal peritoneal metastases. Second-look surgery consisted of a complete exploration of the abdominal cavity via xyphopubic incision, and resection of all peritoneal implants if resectable. Surveillance after resection of colorectal cancer was done according to the French Guidelines. The primary outcome was 3-year disease-free survival, defined as the time from randomisation to peritoneal or distant disease recurrence, or death from any cause, whichever occurred first, analysed by intention to treat. Surgical complications were assessed in the second-look surgery group only. This study was registered at ClinicalTrials.gov, NCT01226394.

FINDINGS

Between June 11, 2010, and March 31, 2015, 150 patients were recruited and randomly assigned to a treatment group (75 per group). After a median follow-up of 50·8 months (IQR 47·0-54·8), 3-year disease-free survival was 53% (95% CI 41-64) in the surveillance group versus 44% (33-56) in the second-look surgery group (hazard ratio 0·97, 95% CI 0·61-1·56). No treatment-related deaths were reported. 29 (41%) of 71 patients in the second-look surgery group had grade 3-4 complications. The most common grade 3-4 complications were intra-abdominal adverse events (haemorrhage, digestive leakage) in 12 (23%) of 71 patients and haematological adverse events in 13 (18%) of 71 patients.

INTERPRETATION

Systematic second-look surgery plus oxaliplatin-HIPEC did not improve disease-free survival compared with standard surveillance. Currently, essential surveillance of patients at high risk of developing colorectal peritoneal metastases appears to be adequate and effective in terms of survival outcomes.

FUNDING

French National Cancer Institute.

CpG-methylation-based risk score predicts progression in colorectal cancer

Aim: To identify patients with colorectal cancer (CRC) who are at a truly higher risk of progression, which is key for individualized approaches to precision therapy. Materials & methods: We developed a predictor associated with progression-free interval (PFI) using The Cancer Genome Atlas CRC methylation data. Results: The risk score was associated with PFI in the whole cohort (p < 0.001). A nomogram consisting of the risk score and other significant clinical features was generated to predict the 3- and 5-year PFI in the whole set (area under the curve: 0.79 and 0.71, respectively). Conclusion: The risk score based on 23 DNA-methylation sites may serve as the basis for improved prediction of progression in patients with CRC in future clinical practice.

Synchronous and Metachronous Peritoneal Metastases in Patients with Left-Sided Obstructive Colon Cancer

Background

Controversy exists on emergency setting as a risk factor for peritoneal metastases (PM) in colon cancer patients. Data in patients with obstruction are scarce. The aim of this study was to determine the incidence of synchronous and metachronous PM, risk factors for the development of metachronous PM, and prognostic implications within a large nationwide cohort of left-sided obstructive colon cancer (LSOCC).

Methods

Patients with LSOCC treated between 2009 and 2016 were selected from the Dutch ColoRectal Audit. Additional treatment and long-term outcome data were retrospectively collected from original patient files in 75 hospitals in 2017.

Results

In total, 3038 patients with confirmed obstruction and without perforation were included. Synchronous PM (at diagnosis or < 30 days postoperatively) were diagnosed in 148/2976 evaluable patients (5.0%), and 3-year cumulative metachronous PM rate was 9.9%. Multivariable Cox regression analyses revealed pT4 stage (HR 1.782, 95% CI 1.191–2.668) and pN2 stage (HR 2.101, 95% CI 1.208–3.653) of the primary tumor to be independent risk factors for the development of metachronous PM. Median overall survival in patients with or without synchronous PM was 20 and 63 months (p < 0.001) and 3-year overall survival of patients that did or did not develop metachronous PM was 48.1% and 77.0%, respectively (p < 0.001).

Conclusion

This population based study revealed a 5.0% incidence of synchronous peritoneal metastases in patients who underwent resection of left-sided obstructive colon cancer. The subsequent 3-year cumulative metachronous PM rate was 9.9%, with advanced tumor and nodal stage as independent risk factors for the development of PM.

Electronic supplementary material

The online version of this article (10.1245/s10434-020-08327-7) contains supplementary material, which is available to authorized users.

Colorectal peritoneal metastases: pathogenesis, diagnosis and treatment options - an evidence-based update

Peritoneal metastases confer the worst survival among all sites in patients with metastatic colorectal cancer. They develop largely through transcoelomic spread, with a sequence of events that allow cells to first detach from primary tumours, survive in the peritoneal environment, attach to the peritoneal surface of organs and migrate into the submesothelial space to create a microenvironment conducive to metastatic growth. Diagnostic challenges have previously hindered early identification of peritoneal metastases. While advances in diagnostic modalities have improved our ability to identify peritoneal metastases, lesions under 0.5 cm remain challenging to detect. The advent of cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC) can offer selected patients with colorectal peritoneal metastases a favourable long-term survival. Recent trials, however, have cast doubts on the efficacy of HIPEC, with the recent PRODIGE 7 trial showing no benefit from oxaliplatin based HIPEC in addition to good quality cytoreductive surgery in resectable disease. While peritoneal recurrence can be reliably predicted from high-risk features in primary tumours such as a perforated cancer, ovarian metastases or T4a cancers, the use of prophylactic second look surgery with HIPEC or adjuvant HIPEC failed to demonstrate any survival benefit in high-risk cases in recent clinical trials, raising further questions about the efficacy of HIPEC. With high failure rates from systemic chemotherapy in unresectable disease, novel surgical techniques such as pressurized intraperitoneal aerolized chemotherapy are being investigated in clinical trials worldwide. Further collaborative research is needed to explore newer avenues of treatment for this poor prognostic cohort.

Perceptions in the management of colorectal peritoneal metastases: A bi-national survey of colorectal surgeons

BACKGROUND

There is great variability in the uptake of cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) in the management of colorectal peritoneal metastases (CRPM) in Australia and New Zealand. This study aims to provide a snapshot of perceptions among colorectal surgeons in the management of CRPM.

METHODS

A structured ten-question online survey was sent to all colorectal surgeons, with three questions on clinical experience and demographics, one on health economics and six on hypothetical clinical scenarios. Scores were collated and reported based on Likert scales.

RESULTS

Eighty-one respondents (36.2%) completed the survey. Most surgeons (66.7%) strongly disagreed with offering CRS and HIPEC at all hospitals. The majority (87.7%) agreed that CRS and HIPEC offered a higher survival benefit than systemic chemotherapy in pseudomyxoma peritonei (PMP), and 69.1% in CRPM (comparators: 60.5% ovarian cancer, 14.8% gastric cancer). There were mixed strategies in managing low-volume, isolated peritoneal recurrences. The majority did not recommend second-look laparoscopy, but favoured operative management of Krukenberg tumours. In the presence of incidental peritoneal metastases, only 29.6% favoured biopsy only and referring the patient to a peritoneal disease centre.

CONCLUSIONS

Response rate was relatively low. In Australia and New Zealand, colorectal surgeons see a strong role for CRS and HIPEC in the management of PMP and CRPM. The role of "second look" surgery in high-risk cases is controversial and not supported. Krukenberg tumours are viewed as surgical disease. Regular updates and collaboration with peritoneal centres may help surgeons stay abreast with latest evidence in the field.

Patients with extensive regional lymph node involvement (pN2) following potentially curative surgery for colorectal cancer are at increased risk for developing peritoneal metastases: a retrospective single-institution study

AIM

Our goal was to determine the incidence and clinical behaviour of peritoneal metastases (PM) in patients with colorectal cancer undergoing potentially curative surgery, comparing patients with extensive locoregional lymph node involvement (pN2) with those who have serosal involvement (pT4), a known risk factor for developing PM.

METHOD

A retrospective analysis of a prospectively maintained database was performed. All patients with pT4 and pN2 were included in the analysis. The diagnostic criteria were the finding of PM during surgery with biopsy confirmation as well as imaging features suggestive of PM, including ovarian metastases and omental deposits.

RESULTS

Two hundred and fourteen patients treated between May 2010 and October 2015 were included. Of these, 110 (51.4%) had pT4 and 131 (61.2%) pN2 tumours: 17.2% of patients with pT4 tumours and 20.2% of patients with pN2 tumours developed PM (P = 0.53). The median time to detection of PM was 16.6 months and 11.8 months for pT4 and pN2 tumours, respectively. PM were isolated in 51.8% of patients with pN2 tumours. Nonperitoneal metastases developed in 37.5% of patients with pN2 tumours. In pN2 tumours, the incidence of PM was higher in signet ring cell and mucinous tumours (P < 0.01), positive surgical margins (P = 0.02), colonic versus rectal tumours (P = < 0.01) and right colon primary tumours (P = 0.01).

CONCLUSION

Patients with pN2 tumours are at an increased risk of developing PM, which is similar to the risk in pT4 tumours. pN2 tumours should be included in clinical trials evaluating preventive/proactive strategies. There is a need to identify predictive biomarkers for the development of PM versus other sites of metastasis.

Prevention and Treatment of Peritoneal Metastases: a Comprehensive Review

Peritoneal metastases may occur from a majority of cancers that occur within the abdomen or pelvis. When cancer spread to the peritoneal surfaces is documented, a decision regarding palliation versus an aggressive approach using cytoreductive surgery (CRS) and hyperthermic perioperative intraperitoneal chemotherapy (HIPEC) must be made. This decision is dependent on a well-defined group of prognostic indicators. In addition to treatment, prevention of peritoneal metastases may be an option. The clinical and pathologic features of a primary cancer can be used to select perioperative treatments that may prevent cancer cells within the abdomen and pelvis from progressing to established peritoneal metastases. In some clinical situations with appendiceal and colorectal cancers, the clinical or histopathologic features may indicate that second-look surgery plus perioperative chemotherapy should occur. Peritoneal metastases should always be considered by the multidisciplinary team for treatment or prevention.

Peritoneal Metastases from Gastrointestinal Cancer

PURPOSE OF REVIEW

Peritoneal metastases may occur from a majority of cancers that occur within the abdomen or pelvis. When cancer spread to the peritoneal surfaces is documented, a decision regarding palliation vs. an aggressive approach using cytoreductive surgery (CRS) and perioperative intraperitoneal chemotherapy must be made. The perioperative chemotherapy may be hyperthermic intraperitoneal chemotherapy (HIPEC) administered in the operating room or early postoperative intraperitoneal chemotherapy (EPIC) administered in the first 4 or 5 postoperative days.

RECENT FINDINGS

This decision is dependent on a well-defined group of prognostic indicators. In addition to treatment, the clinical and pathologic features of a primary cancer can be used to select perioperative treatments that may prevent cancer cells within the abdomen and pelvis from progressing to established peritoneal metastases. In some clinical situations with appendiceal and colorectal cancers, the clinical or histopathologic features may indicate that second-look surgery plus perioperative chemotherapy should occur. Peritoneal metastases should always be considered for treatment or prevention.

[Surgical treatment of peritoneal metastases of colorectal cancer]

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) may significantly improve overall survival in selected patients with peritoneal metastases of colorectal cancer. For good oncological results complete macroscopic cytoreduction is crucial; furthermore, a linear correlation between peritoneal tumor load, as determined by the peritoneal cancer index (PCI) and overall survival has been demonstrated; therefore, surgical treatment should be initiated as early as possible. Synchronous resection of up to three liver metastases may be performed safely and with good results and no influence on the morbidity. With respect to intraperitoneal chemotherapy, mitomycin C and oxaliplatin are most commonly used and may be regarded as equal; however, for perioperative chemotherapy study results are so far inconclusive with some trials hinting at decreased overall survival following neoadjuvant chemotherapy. Adjuvant therapy is likely to improve overall survival if at least 6 cycles are applied. Early detection of peritoneal metastases is difficult at present but might be facilitated in the future by the use of liquid biopsies, which may detect circulating free tumor-specific DNA or RNA. In the meantime, planned second-look laparotomy should be considered for patients at high risk of peritoneal recurrence. In addition, several international studies are currently evaluating the concept of adjuvant or prophylactic HIPEC. The CRS and HIPEC may be repeated in cases of recurrence and should be considered in suitable patients, applying the same criteria as for primary CRS and HIPEC. A recurrence-free interval of >2 years is associated with a significantly better prognosis.