Peritoneal carcinomatosis is less frequently diagnosed during laparoscopic surgery compared to open surgery in patients with colorectal cancer

Laparoscopic surgery is associated with increased risk of postoperative peritoneal metastases in T4 colon cancer: a propensity score analysis

BACKGROUND

This study aims to evaluate the postoperative safety, long-term survival, and postoperative peritoneal metastases (PPM) rate associated with laparoscopic surgery (LS) for T4 colon cancer.

MATERIALS AND METHODS

After propensity score matching, there were 68 patients in each of the LS and Open surgery groups. The primary outcomes were the 3-year OS, DFS, and PPM rates.

RESULTS

After matching, 68 patients in each of the groups. The LS group had a higher cumulative 3-year peritoneal metastasis rate (19.8% vs. 6.7%, P = .036), while the 3-year OS (82.3% vs. 83.8%, P = .750) and 2-year DFS (69.0% vs. 75.7%, P = .310) showed no significant difference, compared to the open surgery group. The LS group had a significantly longer operation time (201 ± 85.7 min vs. 164 ± 65.9 min, P = .008) but less postoperative complications (P = .036). Additionally, patients in the LS group removed gastric tube more quickly (1.91 ± 1.18 days vs. 2.69 ± 2.41 days, P = .048). The multivariate analysis revealed that LS (HR = 3.496, 95% CI = 1.108-11.030, P = .033), underweight (HR = 11.650, 95% CI = 2.155-62.990, P = .004), and lymphovascular invasion (HR = 3.123, 95% CI = 1.010-9.664, P = .048) were all predictive factors of PPM. For the pN + subgroup, the 3-year cumulative PPM rate was 29.6% in the LS group, significantly higher than 15.3% in the open group (P = .029), but there was no significant difference after PSM (P = .100).

CONCLUSION

LS offers faster postoperative recovery and comparable long-term survival outcomes. Therefore, it should remain a viable option for locally advanced T4 colon cancer. However, it is crucial to fully recognize the potential risk of increased PPM associated with LS, especially in patients with preoperative suspicion of positive lymph nodes. Further multicenter prospective studies are necessary to validate the potential risks of LS and gain insight into treatment efficacy in different patient populations. In addition, future studies should assess prognosis based on the grade and extent of peritoneal dissemination to provide a more nuanced understanding.

Staging peritoneal metastases in colorectal cancer: The correlation between MRI, surgical and histopathological peritoneal cancer index

INTRODUCTION

DW-MRI is a non-invasive way to determine the peritoneal cancer index (PCI) in colorectal cancer (CRC) patients with peritoneal metastases (PM). However, like surgeons during surgery, radiologists struggle to differentiate between PM and fibrosis. This study aimed to investigate the agreement between the PCI as determined by MRI (mriPCI), during surgery (sPCI) and histopathology examination (pPCI) in CRC patients undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC).

MATERIALS AND METHODS

This was a single-centre, retrospective study of CRC patients with PM who were staged with DW-MRI and underwent subsequent CRS-HIPEC. All initial patients' radiological, surgical and histopathology reports were reviewed for the PCI. Histopathology was the reference standard. Primary outcome was the correlation and agreement between mriPCI and pPCI.

RESULTS

Eighty-seven patients were included. All patients had a complete macroscopic resection. Median (interquartile range) PCI for MRI, surgery, and histopathology were respectively 6.0 (2.5-9.0), 6.0 (4.0-11.0) and 6.0 (2.5-9.5). The intraclass correlation coefficient between the sPCI and pPCI was excellent 0.87 (p <0.001), and good between mriPCI and pPCI 0.77 (p <0.001) and between sPCI and mriPCI 0.70 (p <0.001).

CONCLUSION

MRI is a promising non-invasive tool to assess the PCI rather accurately.

Peritoneal carcinomatosis in mouse models

Peritoneal carcinomatosis (PCa) represents a metastatic stage of a disease with unmet therapeutic options. Malignant cells from primary tumors (gastrointestinal or gynecologic malignancies) invade the peritoneal cavity and eventually seed onto peritoneal surfaces, with the omentum being the most common nest area. With a median survival of less than 6 months, PCa has a dismal prognosis that can be improved with treatments only available to a select few individuals with low tumor burden. Thus, the discovery of novel and effective therapies for this disease depends on reliable animal models. Here, we describe a method to generate syngeneic PCa mouse models based on intraperitoneal (i.p.) administration of tumor cells. This model allows to follow-up cancer progression in PCa models from ovarian and colorectal origins monitoring mice bodyweight changes, ascites development and overall survival. Moreover, luciferase-expressing tumor cells can also be used to assess tumor growth after i.p. injection through in vivo bioluminescence quantification. The establishment of reliable, easy-to-monitor and reproducible intraperitoneal syngeneic tumors models, as described here, is the first step to develop cutting-edge therapies against PCa.

A prediction model to refine the timing of an early second-look laparoscopic exploration in patients with colon cancer at high risk of early peritoneal metastasis recurrence

BACKGROUND

In patients at high risk of peritoneal metastasis (PM) recurrence following surgical treatment of colon cancer (CC), second-look laparoscopic exploration (SLLE) is mandatory; however, the best timing is unknown. We created a tool to refine the timing of early SLLE in patients at high risk of PM recurrence.

METHODS

This international cohort study included patients who underwent CC surgery between 2009 and 2020. All patients had PM recurrence. Factors associated with PM-free survival (PMFS) were assessed using Cox regression. The primary endpoint was early PM recurrence defined as a PMFS of <6 months. A model (logistic regression) was fitted and corrected using bootstrap.

RESULTS

In total, 235 patients were included. The median PMFS was 13 (IQR, 8-22) months, and 15.7% of the patients experienced an early PM recurrence. Synchronous limited PM and/or ovarian metastasis (hazard ratio [HR]: 2.50; 95% confidence interval [CI]: [1.66-3.78]; p < 0.001) were associated with a very high-risk status requiring SLLE. T4 (HR: 1.47; 95% CI: [1.03-2.11]; p = 0.036), transverse tumor localization (HR: 0.35; 95% CI: [0.17-0.69]; p = 0.002), emergency surgery (HR: 2.06; 95% CI: [1.36-3.13]; p < 0.001), mucinous subtype (HR: 0.50; 95% CI [0.30, 0.82]; p = 0.006), microsatellite instability (HR: 2.29; 95% CI [1.06, 4.93]; p = 0.036), KRAS mutation (HR: 1.78; 95% CI: [1.24-2.55]; p = 0.002), and complete protocol of adjuvant chemotherapy (HR: 0.93; 95% CI: [0.89-0.96]; p < 0.001) were also prognostic factors for PMFS. Thus, a model was fitted (area under the curve: 0.87; 95% CI: [0.82-0.92]) for prediction, and a cutoff of 150 points was identified to classify patients at high risk of early PM recurrence.

CONCLUSION

Using a nomogram, eight prognostic factors were identified to select patients at high risk for early PM recurrence objectively. Patients reaching 150 points could benefit from an early SLLE.

The impact of an open or laparoscopic approach on the development of metachronous peritoneal metastases after primary resection of colorectal cancer: results from a population-based cohort study

BACKGROUND

This study aimed to assess the impact of open or laparoscopic resection of primary colorectal cancer (CRC) on the development of metachronous colorectal peritoneal metastases (CPM) in a population-based cohort.

MATERIALS AND METHODS

This was a retrospective, population-based study of CRC patients who underwent open or laparoscopic resection of the primary tumour in the Netherlands between January 1st and June 30th 2015. Patients with synchronous metastases were excluded. CPM were considered metachronous if diagnosed ≥ 90 days after resection of primary CRC. Multivariable cox regression analysis was performed to correct for tumour location, histology, differentiation, and stage, nodal stage, tumour perforation, primary surgery type, and unclear resection margins.

RESULTS

In total, 1516 CRC patients underwent open resection and 3236 CRC patients underwent laparoscopic resection, with a 3-year cumulative incidence of metachronous CPM of 7.3% and 3.7%, respectively (p < 0.001), after median follow-up of 42 months. Open surgical approach was significantly associated with the development of metachronous CPM: HR 1.4 [95%CI 1.1-1.8]. Other prognostic factors were mucinous adenocarcinoma histology (HR 1.6, 95%CI 1.0-2.5), T4 stage (HR 3.2, 95%CI 2.3-4.5), N1 stage (HR 2.9, 95%CI 2.1-4.0), and N2 stage (HR 4.2, 95%CI 2.9-6.1).

CONCLUSIONS

Patients treated with open resection had a significantly higher risk to develop metachronous CPM than patients treated with laparoscopic resection. The mechanisms underlying this phenomenon remain unknown but might be related to differences in per-operative specimen handling, tumour spill, surgical trauma and pro-inflammatory response. This finding might imply the need for a personalized follow-up after primary resection of CRC.

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.

Adjuvant hyperthermic intraperitoneal chemotherapy in patients with locally advanced colon cancer (COLOPEC): a multicentre, open-label, randomised trial

BACKGROUND

Nearly a quarter of patients with locally advanced (T4 stage) or perforated colon cancer are at risk of developing peritoneal metastases, often without curative treatment options. We aimed to determine the efficacy of adjuvant hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with locally advanced colon cancer.

METHODS

This multicentre, open-label trial was done in nine hospitals that specialised in HIPEC in the Netherlands. Patients with clinical or pathological T4N0-2M0-stage tumours or perforated colon cancer were randomly assigned (1:1), with a web-based randomisation application, before resection of the primary tumour, to adjuvant HIPEC followed by routine adjuvant systemic chemotherapy (experimental group) or to adjuvant systemic chemotherapy alone (control group). Patients were stratified by tumour characteristic (T4 or perforation), age (<65 years or ≥65 years), and surgical approach of the primary tumour resection (laparoscopic or open). Key eligibility criteria included age between 18 and 75 years, adequate clinical condition for HIPEC, and intention to start adjuvant systemic chemotherapy. Patients with metastatic disease were ineligible. Adjuvant HIPEC consisted of fluorouracil (400 mg/m²) and leucovorin (20 mg/m²) delivered intravenously followed by intraperitoneal delivery of oxaliplatin (460 mg/m²) for 30 min at 42°C, delivered simultaneously or within 5-8 weeks after primary tumour resection. In all patients without evidence of recurrent disease at 18 months, a diagnostic laparoscopy was done. The primary endpoint was peritoneal metastasis free-survival at 18 months, measured in the intention-to-treat population, with the Kaplan-Meier method. Adverse events were assessed in all patients who received assigned treatment. This study is registered with ClinicalTrials.gov, number NCT02231086.

FINDINGS

Between April 1, 2015, and Feb 20, 2017, 204 patients were randomly assigned to treatment (102 in each group). In the HIPEC group, two patients withdrew consent after randomisation. In this group, 19 (19%) of 100 patients were diagnosed with peritoneal metastases: nine (47%) during surgical exploration preceding intentional adjuvant HIPEC, eight (42%) during routine follow-up, and two (11%) during diagnostic laparoscopy at 18-months. In the control group, 23 (23%) of 102 patients were diagnosed with peritoneal metastases, of whom seven (30%) were diagnosed by laparoscopy at 18-months and 16 during regular follow-up (therefore making them ineligible for diagnostic laparoscopy). In the intention-to-treat analysis (n=202), there was no difference in peritoneal-free survival at 18-months (80·9% [95% CI 73·3-88·5] for the experimental group vs 76·2% [68·0-84·4] for the control group, log-rank one-sided p=0·28). 12 (14%) of 87 patients who received adjuvant HIPEC developed postoperative complications and one (1%) encapsulating peritoneal sclerosis.

INTERPRETATION

In patients with T4 or perforated colon cancer, treatment with adjuvant HIPEC with oxaliplatin did not improve peritoneal metastasis-free survival at 18 months. Routine use of adjuvant HIPEC is not advocated on the basis of this trial.

FUNDING

Organization for Health Research and Development and the Dutch Cancer Society.

Colorectal Peritoneal Metastases: A Systematic Review of Current and Emerging Trends in Clinical and Translational Research

Colorectal peritoneal metastases (CPM) are associated with abbreviated survival and significantly impaired quality of life. In patients with CPM, radical multimodality treatment consisting of cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) has demonstrated oncological superiority over systemic chemotherapy alone. In highly selected patients undergoing CRS + HIPEC, overall survival of over 60% has been reported in some series. These are patients in whom the disease burden is limited and where the diagnosis is made at an early stage in the disease course. Early diagnosis and a deeper understanding of the biological mechanisms that regulate CPM are critical to refining patient selection for radical treatment, personalising therapeutic approaches, enhancing prognostication, and ultimately improving long-term survivorship. In the present study, we outline three broad themes which represent critical future research targets in CPM: (1) enhanced radiological strategies for early detection and staging; (2) identification and validation of translational biomarkers for diagnostic, prognostic, and therapeutic deployment; and (3) development of optimized approaches for surgical cytoreduction as well as more precise strategies for intraperitoneal drug selection and delivery. Herein, we provide a contemporary narrative review of the state of the art in these three areas. A systematic review in accordance with PRISMA guidelines was undertaken on all English language studies published between 2007 and 2017. In vitro and animal model studies were deemed eligible for inclusion in the sections pertaining to biomarkers and therapeutic optimisation, as these areas of research currently remain in the early stages of development. Acquired data were then divided into hierarchical thematic categories (imaging modalities, translational biomarkers (diagnostic/prognostic/therapeutic), and delivery techniques) and subcategories. An interactive sunburst figure is provided for intuitive interrogation of the CPM research landscape.

Risk factors for appendiceal and colorectal peritoneal metastases

BACKGROUND

Early diagnosis to target minimal volume disease has received increased attention in the management of appendiceal and colorectal peritoneal metastases (PM). This study aimed to identify risk factors for appendiceal, colon and rectal PM.

METHODS

Data were retrieved from the Swedish Colorectal Cancer Registry for all patients undergoing bowel resection of appendiceal and colorectal tumours, in Sweden, 2007-2015. Risk factors for synchronous and metachronous PM were analysed with multivariate logistic and Cox proportional hazard regression models.

RESULTS

Synchronous PM was most common in appendiceal cancer (23.5%), followed by colon (3.1%) and rectal (0.6%) cancer. The 5-year cumulative incidence was 9.0% for appendiceal, 2.5% for right colon, 1.8% for left colon and 1.2% for rectal cancer. In appendiceal cancer (n = 327), T4, N2, mucinous tumour, and non-radical surgery were associated with PM. In colon cancer (n = 24,399), synchronous PM were primarily associated with T4 (OR 18.37, 95% CI 8.12-41.53), T3 and N2 but also with N1, right-sided tumour, mucinous tumour, vascular and perineural invasion, female gender, age <60 and emergency surgery. These factors were also associated with metachronous PM. In rectal cancer (n = 10,394), T4 (OR 19.12, 95% CI 5.52-66.24), proximal tumour and mucinous tumour were associated with synchronous PM and T4 and mucinous tumour with metachronous PM.

CONCLUSIONS

This study shows that appendiceal cancer, right-sided colon cancer, advanced tumour and node stages and mucinous histopathology are the main high-risk features for PM and should increase the awareness of current or future PM.

Treatment of peritoneal carcinomatosis with hyperthermic intraperitoneal chemotherapy in colorectal cancer

The peritoneum is the second most common site of metastasis after the liver and the only site of metastatic disease in approximately 25% of patients with colorectal cancer (CRC). In the past, peritoneal carcinomatosis in CRC was thought to be equivalent to distant metastasis; however, the transcoelomic spread of malignant cells is an acknowledged alternative pathway. Metastasectomy with curative intent is well accepted in patients with liver metastasis in CRC despite the paucity of randomized trials. Therefore, there is rationale for local treatment with peritonectomy to eliminate macroscopic disease, followed by hyperthermic intraperitoneal chemotherapy to destroy any residual free tumour cells within the peritoneal cavity. The aim of this paper is to summarize the current evidence for cytoreduction and hyperthermic intraperitoneal chemotherapy in the treatment of peritoneal carcinomatosis in CRC.

Postoperative complications affect long-term outcomes after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for colorectal peritoneal carcinomatosis

BACKGROUND AND OBJECTIVES

Morbidity after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS + HIPEC) for colorectal peritoneal carcinomatosis (PC) may negatively affect survival. The objective was to determine the impact of postoperative complications (CX) on survival in patients undergoing CRS + HIPEC for colorectal PC.

METHODS

All patients undergoing laparotomy for planned CRS + HIPEC for colorectal PC at a single institution from 1999 to 2014 were included. Patients were divided into three groups: CRS + HIPEC without CX (+HIPEC-CX); CRS + HIPEC with postoperative complication (+HIPEC + CX); and aborted CRS and HIPEC due to unresectable disease (-HIPEC). Postoperative morbidity were defined as Clavien II+ complications. Kaplan-Meier survival analyses and multivariable Cox proportional hazard modeling were used to describe the disease-free (DFS) and overall survival (OS).

RESULTS

One hundred and twenty-two patients were included in the analysis (50 +HIPEC - CX, 40 +HIPEC + CX, 32-HIPEC). Overall complication rate was 42%. OS at 1-, 3-, and 5-years in patients undergoing successful CRS + HIPEC were 97%, 67%, and 45%. CX after successful CRS + HIPEC was independently associated with worsened OS (HR1.58, 95%CI, 1.19-1.97) but not DFS (HR1.11, 95%CI, 0.56-2.20). PCI also independently predicted worsened DFS (HR1.12, 95%CI, 1.06-1.18) and OS (HR1.08, 95%CI, 1.04-1.12). Patients with unresectable disease had significantly worse OS (HR6.50, 95%CI, 1.37-7.01).

CONCLUSIONS

CX after CRS + HIPEC significantly affect OS. Patient selection and perioperative care are of paramount importance in the management of CRS + HIPEC for colorectal PC.

Oligometastatic Disease in the Peritoneal Space with Gastrointestinal Cancer

OBJECTIVES

Treatment options for patients with gastrointestinal cancer and oligometastastic disease remain the domain of the medical oncologist. However, in selected cases, attempts to remove or destroy the tumor burden seem appropriate.

BACKGROUND DATA

During the last decade, the treatment of localized and isolated tumor nodules, such as lung, liver or peritoneal metastasis, has changed. Previously, these patients with metastatic disease only received palliative chemotherapy. Combined treatment approaches and new techniques demonstrate that additional surgery to destroy or remove the metastases seem to be of major benefit to patients.

METHODS

The recently published important literature regarding peritoneal metastases and oligometastases in gastrointestinal cancer was analyzed.

RESULTS

The most important factor in the treatment of peritoneal metastases and in cytoreductive surgery is patient selection. Resection of peritoneal metastases should be considered. Hyperthermic intraperitoneal chemotherapy is feasible. However, further results of randomized trials are necessary. Several randomized trials are on the way and will be available in 1-2 years. Systemic chemotherapy alone as an adequate management plan for all sites of metastatic disease is not compatible with a high standard of care. Formulating an optimal plan combining re-operative surgery with regional plus systemic chemotherapy is a necessary task of the multidisciplinary team.

CONCLUSIONS

In oligometastastic disease of gastrointestinal cancer origin, the selection process is the most important factor for survival. Further studies are needed to determine optimal treatment options.

Treatment of peritoneal surface malignancies with hyperthermic intraperitoneal chemotherapy-current perspectives

Peritoneal carcinomatosis (ptc) represents advanced malignant disease and has generally been associated with a grim prognosis. Peritoneal surface malignancy is often the major source of morbidity and mortality; it is of major concern in cancer management. Although ptc is categorized as metastatic disease, it represents a special disease pattern considered to be a locoregional disease limited to the abdominal cavity. The combination of cytoreductive surgery (crs) and intraoperative hyperthermic intraperitoneal chemotherapy (hipec) has successfully been used as locoregional treatment for selected patients with ptc from gastric, colorectal, and ovarian cancer; with mesothelioma; and with pseudomyxoma peritonei. In the prophylactic setting, hipec can also be used to prevent ptc in high-risk patients, and the first results of the "second-look" approach are promising. Patient selection-in which the risks of perioperative morbidity and mortality, which are analogous to those for any other major gastrointestinal surgery, are assessed-is of utmost importance. Those risks have to be weighed against the anticipated survival benefit, which depends mainly on tumour biology, extent of disease, and probability of achieving complete crs. The present review discusses the principles of crs and hipec, the most significant recent clinical data, and current perspectives concerning the application of this treatment modality in various malignancies. Ongoing trials and future directions are noted. It appears that the combination of crs and hipec is an indispensable tool in the oncologist's armamentarium.

Surgical technology and pharmacology of hyperthermic perioperative chemotherapy

Although cytoreductive surgery (CRS) and hyperthermic perioperative chemotherapy (HIPEC) have not been shown to be effective by themselves, as a combined treatment they are now standard of care for peritoneal metastases from appendiceal cancer and from colorectal cancer as well as peritoneal mesothelioma. The timing of the HIPEC in relation to the CRS is crucial in that the HIPEC is to destroy minimal residual disease that remains following the CRS and prevent microscopic tumor emboli within the abdomen and pelvis from implanting within the resection site, within fibrinous clot, or within blood clot. Proper selection of chemotherapy agents is crucial to the long-term benefit of CRS and HIPEC. One must consider the response expected with the cancer chemotherapy agent, its area under the curve (AUC) ratio indicating the amount of dose intensity within the peritoneal space, and the drug retention within the peritoneal space for a prolonged exposure. Hyperthermia will augment the cytotoxicity of the cancer chemotherapy agents and improve drug penetration. Irrigation techniques should not be overlooked as an important means of reducing the cancer cell burden within the abdomen and pelvis. Multiple technologies for HIPEC exist and these have advantages and disadvantages. The techniques vary from a totally open technique with a vapor barrier over the open abdominal space to a totally closed technique whereby the HIPEC is administered at the completion of the surgical procedure. The open techniques depend on a table-mounted retractor for suspension of the skin edges allowing a reservoir to occur within the abdomen and pelvis. There are nearly a dozen commercially available hyperthermia pumps, all of which seem to perform adequately for HIPEC although there is a variable degree of convenience and documentation of the HIPEC procedure. As the management of peritoneal metastases has progressed over three decades, early cases are now seen in which a laparoscopic CRS and HIPEC may be appropriate. Also, prophylactic use of laparoscopic HIPEC with perforated appendiceal malignancies and T4 colon cancers may be appropriate.

Progress in treatments for colorectal cancer peritoneal metastases during the years 2010-2015. A systematic review

Peritoneal metastases (PM) from colorectal cancer (CRC) were traditionally associated with bad prognosis. Only recently, cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has resulted in survival improvements. A systematic literature search between January 2010 and June 2015 was performed. Studies were selected and appraised according to predetermined criteria. Nineteen cohort studies, and thirteen comparative studies of CRS/HIPEC were included. The weighted median overall survival was 31.6 months (range 16-51). Major morbidity was 17.6-52.4% (weighted average 32.6%). Mortality was 0-8.1% (weighted average 2.9%). Additional relevant topics, such as CRC-PM prevalence, results by systemic therapies, preoperative work-up, and technical aspects were summarized through a narrative review. The recent literature suggests that CRS/HIPEC is gaining acceptance as standard of care for selected CRC-PM patients. Refinement of selection criteria, and rationalization of comprehensive systemic and local-regional management is ongoing. Prevention and early treatment of PM are new and promising options.

Immuno-PCI: a proposal for the implementation of "seed and soil" concept in the treatment of peritoneal carcinomatosis from colorectal cancer

The advent of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy has revolutionized the approach to peritoneal carcinomatosis of colorectal cancer origin in appropriately selected cases. However, the high postoperative morbidity and mortality following the procedure underlines the need for optimizing the patient selection criteria, finally aiming to establish a patient-tailored approach. The introduction of tools enabling the quantification of the peritoneal spread of the metastatic deposits has been of paramount importance in the decision-making and the estimation of the prognosis. However, we believe that it is high time to attempt a further evolution of the current practice, by incorporating in the above mentioned quantification scores parameters indicative of the immune-response against the disease progression, fact which will probably reflect more accurately the dynamics of cancer progression and will sequentially be a crucial step towards individualized treatment of peritoneal carcinomatosis.