Treatment Strategies and Prognosis of Patients With Synchronous or Metachronous Colorectal Peritoneal Metastases: A Population-Based Study.

BACKGROUND: This study aimed to compare treatment strategies and survival of patients with synchronous colorectal peritoneal metastases (CPM) and patients with metachronous CPM in a nationwide cohort. METHODS: All patients from the Netherlands Cancer Registry with synchronous or metachronous CPM whose primary colorectal cancer (CRC) was diagnosed between 1 January and 30 June 2015 were included in the study. Treatments were categorized as (A) cytoreductive surgery and hyperthermic intraperitoneal chemotherapy [CRS-HIPEC]; (B) palliative treatment; or (C) best supportive care. Overall survival (OS) for all the patients and disease-free survival (DFS) for those who underwent CRS-HIPEC were compared between the two groups. RESULTS: Of 7233 patients, 743 had a diagnosis of CPM, including 409 patients with synchronous CPM and 334 patients with metachronous CPM. The median OS was 8.1 months for the patients with synchronous CPM versus 12 months for the patients with metachronous CPM (p = 0.003). After multivariable correction, OS no longer differed between the patients with synchronous CPM and those with metachronous CPM (HR 1.03 [0.83-1.27]). The patients with metachronous CPM more often underwent CRS-HIPEC than the patients with synchronous CPM (16 % vs 8 %; p = 0.001). The two groups did not differ statistically in terms of DFS and OS (median DFS, 21.5 vs 14.1 months, respectively; p = 0.094; median OS, 37.8 vs. 35.8 months, respectively; p = 0.553). CONCLUSION: This population-based study showed that survival for the patients with synchronous CPM and patients with metachronous CPM did not significantly differ. This suggests that a similar prognosis may be expected for patients selected for treatment regardless of the onset of CPM.

The Delphi and GRADE methodology used in the PSOGI 2018 consensus statement on Pseudomyxoma Peritonei and Peritoneal Mesothelioma.

Pseudomyxoma Peritonei (PMP) and Peritoneal Mesothelioma (PM) are both rare peritoneal malignancies. Currently, affected patients may be treated with Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy offering long-term survival or even cure in selected patients. However, many issues regarding the optimal treatment strategy are currently under debate. To aid physicians involved in the treatment of these patients in clinical decision making, the PSOGI executive committee proposed to create a consensus statement on PMP and PM. This manuscript describes the methodology of the consensus process. The Delphi technique is a reliable method for attaining consensus on a topic that lacks scientific evidence through multiple voting rounds which feeds back responses to the participants in between rounds. The GRADE system provides a structured framework for presenting and grading the available evidence. Separate questionnaires were created for PMP and PM and sent during two voting rounds to 80 and 38 experts, respectively. A consensus threshold of 51.0% was chosen. After the second round, consensus was reached on 92.9%-100.0% of the questions. The results were presented and discussed in the plenary session at the PSOGI 2018 international meeting in Paris. A third round for the remaining issues is currently in progress. In conclusion, using the Delphi technique and GRADE methodology, consensus was reached in many issues regarding the treatment of PM and PMP amongst an international panel of experts. The main results will be published in the near future.

Appendiceal tumours and pseudomyxoma peritonei: Literature review with PSOGI/EURACAN clinical practice guidelines for diagnosis and treatment.

Pseudomyxoma Peritonei (PMP) is a rare peritoneal malignancy, most commonly originating from a perforated epithelial tumour of the appendix. Given its rarity, randomized controlled trials on treatment strategies are lacking, nor likely to be performed in the foreseeable future. However, many questions regarding the management of appendiceal tumours, especially when accompanied by PMP, remain unanswered. This consensus statement was initiated by members of the Peritoneal Surface Oncology Group International (PSOGI) Executive Committee as part of a global advisory role in the management of uncommon peritoneal malignancies. The manuscript concerns an overview and analysis of the literature on mucinous appendiceal tumours with, or without, PMP. Recommendations are provided based on three Delphi voting rounds with GRADE-based questions amongst a panel of 80 worldwide PMP experts.

Increase in the incidence of synchronous and metachronous peritoneal metastases in patients with colorectal cancer: A nationwide study.

INTRODUCTION: - To investigate the incidence of, factors associated with, and differences between synchronous and metachronous colorectal peritoneal metastases (CPM) in a population-based cohort. METHODS: - Data from the Netherlands Cancer Registry were used. All patients diagnosed with colorectal cancer (CRC) between 1 January and June 30, 2015 were evaluated for synchronous or metachronous CPM (diagnosis ≤90 or >90 days after surgery for primary CRC), and survival in 2019 (median follow-up 38.4 months). RESULTS: - Of 7233 included patients, 409 (5.7%) were diagnosed with synchronous CPM. Factors associated with synchronous CPM were mucinous (OR 2.72 [1.90-3.90]) or signet ring cell (SRC) histology (OR 6.58 [3.66-11.81]), T4 (OR 4.82 [3.68-6.32]), N1 (OR 1.66 [1.20-2.30]), or N2 stage (OR 3.27 [2.36-4.52]), and synchronous systemic metastases (SM) (OR 3.13 [2.37-4.14]). After surgery for primary CRC, 326 patients developed metachronous CPM after a median time of 14.7 months (3-year cumulative incidence: 5.5%). Factors associated with metachronous CPM were younger age (HR 1.63 [1.10-2.42]), mucinous (HR 1.84 [1.20-2.82]) or SRC histology (HR 2.43 [1.11-5.32]), T4 (HR 2.77 [2.07-3.70]), N1 (HR 2.90 [2.18-3.85]), N2 (HR 3.19 [2.26-4.50]), and synchronous SM (HR 1.95 [1.43-2.66]). CONCLUSION: - This population-based study found the highest incidence of CPM currently reported in literature and a strong association between the presence of synchronous SM and both synchronous and metachronous CPM. These findings may contribute to a tailored approach in the follow-up after primary CRC surgery and guide future clinical trials investigating new strategies regarding risk-reduction or early detection of metachronous CPM.

Identification of pharmacogenetic biomarkers for efficacy of cytoreductive surgery plus hyperthermic intraperitoneal mitomycin C in patients with colorectal peritoneal metastases.

INTRODUCTION: Mitomycin C (MMC) is commonly used in patients with colorectal peritoneal metastases (CPM) treated with cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy (CRS + HIPEC). MMC requires metabolic activation prior to exert its cytotoxic effect of which the main activating enzymes are NQO1 and POR. However, not all patients are able to activate MMC for example due to polymorphisms in the genes encoding these enzymes. The aim of this study was to investigate the association of NQO1∗2, NQO1∗3, and POR∗28 with the efficacy of CRS + HIPEC with MMC in patients with CPM. METHOD: A retrospective follow-up design was used to study genetic association in patients with histologically proven CPM treated with CRS + HIPEC with MMC with respect to peritoneal recurrence rate after 3 months (primary endpoint), after 6 months, disease-free survival and overall survival. Genetic polymorphisms NQO1∗2, NQO1∗3, and POR∗28 were tested for association. RESULTS: A total of 253 patients were included. In NQO1∗3 carriers the peritoneal recurrence rate 3 and 6 months after HIPEC was significantly higher than in wild type patients, respectively 30.0% vs 3.8% (p = 0.009) and 40.0% vs 12.1% (p = 0.031). In line with these results, NQO1∗3 was associated with a shorter disease-free survival (HR 2.04, 95% CI [1.03-4.03]). There was no significant association with overall survival (HR 1.42, 95% CI [0.66-3.07]). CONCLUSION: Carriership of the NQO1∗3 allele is associated with worse peritoneal recurrence rate and disease-free survival. These results suggest that individualization of patients treated with CRS + HIPEC based upon pharmacogenetics may be beneficial.

Incidence, risk factors, treatment, and survival of ovarian metastases of colorectal origin: a Dutch population-based study.

OBJECTIVE: The aim of this nationwide study was to provide insight in the incidence, risk factors, treatment, and survival of patients with ovarian metastases from colorectal cancer (CRC). METHODS: Data from the Netherlands Cancer Registry were used. All newly diagnosed female CRC patients between 2008 and 2016 were included. Treatment was categorized as follows: cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy (CRS-HIPEC); resection of the primary tumor; palliative treatment; and no treatment. Overall survival (OS) was investigated using Kaplan-Meier and multivariable Cox regression analyses. RESULTS: Of 53,883 female CRC patients, 11,343 (21.1%) had metastases at time of diagnosis. Among them, 471 (4.2%) had ovarian metastases. Within latter group, 27.2% received CRS-HIPEC; 38.4% underwent resection of the primary tumor; 25.3% received palliative treatment; and 9.1% received no treatment. Median OS of all patients with ovarian metastases was 17.5 months. In patients receiving CRS-HIPEC, OS was significantly longer than in patients undergoing resection only (median OS 34.1 vs. 17.5 months, adjusted HR 0.44 [0.33-0.66]). Five-year OS was 28.5% for patients having underwent CRS-HIPEC, 11.0% for patients having underwent resection of the primary tumor, 1.2% for patients having underwent palliative treatment, and 0.0% for patients without treatment. CONCLUSIONS: Synchronous ovarian metastases are diagnosed in 4.2% of female colorectal patients presenting with metastatic disease. Risk factors are young age, T4/N+ tumor and histology of signet ring cell carcinoma. Median OS of the entire cohort was 17.5 months, ranging from 3.1 months in patients without treatment to 34.1 months in patients undergoing CRS-HIPEC.

Appendiceal tumours and pseudomyxoma peritonei: Literature review with PSOGI/EURACAN clinical practice guidelines for diagnosis and treatment

Pseudomyxoma Peritonei (PMP) is a rare peritoneal malignancy, most commonly originating from a perforated epithelial tumour of the appendix. Given its rarity, randomized controlled trials on treatment strategies are lacking, nor likely to be performed in the foreseeable future. However, many questions regarding the management of appendiceal tumours, especially when accompanied by PMP, remain unanswered. This consensus statement was initiated by members of the Peritoneal Surface Oncology Group International (PSOGI) Executive Committee as part of a global advisory role in the management of uncommon peritoneal malignancies. The manuscript concerns an overview and analysis of the literature on mucinous appendiceal tumours with, or without, PMP. Recommendations are provided based on three Delphi voting rounds with GRADE-based questions amongst a panel of 80 worldwide PMP experts.

The Delphi and GRADE methodology used in the PSOGI 2018 consensus statement on Pseudomyxoma Peritonei and Peritoneal Mesothelioma

Pseudomyxoma Peritonei (PMP) and Peritoneal Mesothelioma (PM) are both rare peritoneal malignancies. Currently, affected patients may be treated with Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy offering long-term survival or even cure in selected patients. However, many issues regarding the optimal treatment strategy are currently under debate. To aid physicians involved in the treatment of these patients in clinical decision making, the PSOGI executive committee proposed to create a consensus statement on PMP and PM. This manuscript describes the methodology of the consensus process. The Delphi technique is a reliable method for attaining consensus on a topic that lacks scientific evidence through multiple voting rounds which feeds back responses to the participants in between rounds. The GRADE system provides a structured framework for presenting and grading the available evidence. Separate questionnaires were created for PMP and PM and sent during two voting rounds to 80 and 38 experts, respectively. A consensus threshold of 51.0% was chosen. After the second round, consensus was reached on 92.9%-100.0% of the questions. The results were presented and discussed in the plenary session at the PSOGI 2018 international meeting in Paris. A third round for the remaining issues is currently in progress. In conclusion, using the Delphi technique and GRADE methodology, consensus was reached in many issues regarding the treatment of PM and PMP amongst an international panel of experts. The main results will be published in the near future.