Accuracy and clinical relevance of computed tomography scan interpretation of peritoneal cancer index in colorectal cancer peritoneal carcinomatosis: a multi-institutional study

Treatment and Management of Peritoneal Spread from Appendiceal Neoplasms

Appendiceal neoplasms are rare entities prone to direct peritoneal spread. As these neoplasms occur in few patients, research regarding their management is largely retrospective, limiting its utility. Classification of these neoplasms continues to evolve and is largely based on histopathology. Thorough workup of patients with appendiceal mucinous neoplasms is essential for appropriate management and decision making. The cornerstone of treatment of low-grade and high-grade appendiceal mucinous neoplasms with peritoneal spread is cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS/HIPEC), with limited use of systemic chemotherapy. For those patients who experience recurrence, it may be managed using CRS/HIPEC and possibly systemic chemotherapy.

Treatment and Management of Peritoneal Spread from Colorectal Cancer Peritoneal Metastasis

Peritoneal metastases from colorectal cancer (PMCRC) present a complex treatment challenge requiring multidisciplinary expertise. Significant controversy exists regarding the optimal management of PMCRC patients. In this article, we seek to review the currently available evidence and discuss key components of patient workup, treatment, and management.

Repeat Diagnostic Laparoscopy After Chemotherapy is Useful in Patient Selection for Conversion to Cytoreductive Surgery for Initially Unresectable Colorectal and Appendiceal Peritoneal Metastases: A Retrospective Cohort Study

BACKGROUND

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) enable effective management of colorectal and appendiceal peritoneal metastases (CAPM) despite high morbidity. This study aimed to evaluate the role of repeat diagnostic laparoscopy (rDL) after systemic ± intraperitoneal chemotherapy in the management of initially unresectable CAPM.

METHODS

This retrospective cohort study included 70 consecutive patients with CAPM who underwent initial diagnostic laparoscopy (iDL). Patients with inoperable or equivocal CAPM underwent chemotherapy followed by rDL to assess the treatment response and possibility of conversion to CRS and HIPEC.

RESULTS

Cytoreductive surgery was deemed feasible for 29 patients and unlikely or equivocal for 41 patients based on iDL. Of the 29 resectable patients, 24 successfully underwent CRS and HIPEC after neoadjuvant chemotherapy. Among the 41 patients initially considered unresectable, 16 were deemed operable based on rDL after chemotherapy, and CRS and HIPEC were achieved for 14 patients (conversion). The median peritoneal cancer index was significantly reduced after chemotherapy for the 14 "conversion" patients, from 16 based on iDL to 11 based on rDL (p < 0.05). The conversion rate was 34% (14/41), with a 5-year survival rate of 14%. Treatment with CRS and HIPEC was achieved for 38 of 45 patients deemed operable based on either iDL or rDL (worst-case estimated positive predictive value, 84%).

CONCLUSION

Diagnostic laparoscopy is useful in predicting the likelihood of achieving CRS for patients with CAPM. Despite inoperability based on iDL, patients should be considered for rDL after chemotherapy to assess the possibility of conversion to CRS and HIPEC.

Imaging in malignant peritoneal neoplasms

Peritoneal malignancies encompass a diverse range of tumors originating within the peritoneum, including primary tumors such as mesothelioma and primary serous peritoneal carcinoma or secondary tumors resulting from the spread of cancers from gastrointestinal, gynecological, and extra-abdominal sources. The traditional approach of palliative care for these malignancies is being replaced by a multimodal strategies that integrates surgery with systemic or intraperitoneal chemotherapy. Notably, cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy has shown significant improvements in survival rates. Imaging is crucial in the multidisciplinary management of these tumors, aiding in diagnosis, staging, restaging, and monitoring therapy response. It is also vital for appropriate patient selection, using the acronym "PAUSE", which involves assessing tumor burden via the peritoneal carcinomatosis index, evaluating patients pre- and post-therapy, detecting complications following therapy, and predicting treatment outcomes. This review explores the imaging manifestations of peritoneal malignancies, distinguishing them from various mimics, and underscores the importance of imaging modalities such as CT, MRI, PET/CT, and PET/MRI in effective decision-making and management.

Patient Perspectives of Fertility Following Cytoreductive Surgery With Hyperthermic Intraperitoneal Chemotherapy: An Opportunity for Improved Perioperative Counseling

INTRODUCTION

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) is increasingly performed in young patients with peritoneal surface malignancies. Important quality of life (QoL) questions arise; however, there is limited research on fertility experiences in young women with carcinomatosis or following CRS/HIPEC.

METHODS

Retrospective review of a prospective database evaluating women less than 45 ys who underwent CRS/HIPEC at the University of Pittsburgh Medical Center from January 1998 to 2020. Eligible patients were contacted for a telephone-based interview. Themes regarding fertility counseling, childbearing, and patient-identified issues were investigated.

RESULTS

A total of 28 of 29 women who met inclusion criteria participated. The majority had appendiceal primary (16/28). Most received Mitomycin C intraperitoneal chemotherapy (26/28) with an average Peritoneal Cancer Index of 8 (0-39). Almost half of the women (43%) desired fertility discussion. Although this conversation happened more often in younger patients, 75% were over the age of 35 ys at time of initial HIPEC. Less than half were offered fertility counseling. When fertility conversations occurred, many felt that they were insufficient. In addition to fertility, women cited lack of support on postprocedure hormonal and associated QoL changes.

CONCLUSIONS

As we treat younger females with CRS/HIPEC, we must provide support for age-appropriate QoL issues including fertility and surgical menopause.

Impact of Previous Abdominal Surgery and Timing of Peritoneal Metastases on Accuracy of Imaging in Predicting the Surgical PCI: A Report From the PRECINCT Study

BACKGROUND AND AIM

In this report from Phase 1 of the prospective, observational, PRECINCT (Pattern of peritoneal dissemination and REsponse to systemic Chemotherapy IN Common and uncommon peritoneal Tumours) study, a correlation was performed between the radiological PCI (peritoneal cancer index; rPCI) and surgical PCI (sPCI). The impact of timing of peritoneal malignancy (PM) and previous abdominal surgery was also studied.

METHODS

The rPCI and sPCI were considered the 'same' if they differed by ≤ 3 points. The agreement was assessed using Bland-Altman analysis and the strength of the agreement was assessed using the concordance correlation coefficient (CCC). The extent of prior surgery was classified according to prior surgical score (PSS).

RESULTS

In 707 (79.4%) patients, rPCI and sPCI concurred in 280 (39.6%). In the Bland-Altman analysis, < 40% patients were in the ±3 PCI points limit of acceptable difference. The average difference between the two scores was 4.5 points (95% CI- -5.16 to -3.92). The CCC- was 0.59 for the whole cohort ('moderate' concordance) and was not influenced by imaging modality, timing of PM or PSS.

CONCLUSIONS

The rPCI underestimated sPCI by an average of 4.5 points. The role of peritoneal MRI in patients undergoing iterative procedures and the performance of imaging according to sites of recurrence need further evaluation.

The history of cytoreduction and HIPEC: Heating up or just blowing smoke?

Peritoneal carcinomatosis carries a grim survival prognosis with complications ranging from the physical to the psychological. Cytoreductive surgery and infusion of heated intraperitoneal chemotherapy have evolved to become a commonly used treatment option in the multi-modal management of peritoneal carcinomatosis. Here, we examine the origins of surgery over a century ago as a potential cure for peritoneal carcinomatosis and how it has evolved with our knowledge of the disease to its present state. The origin of chemotherapy is similarly described as well as its progressive application in regional therapy, guided by the ongoing development of new agents, better understanding of peritoneal physiology, and improved systemic treatment. We show how these modalities began to be used in tandem, and standardized, leading to randomized trials and better understanding of the possibilities and limitations of treatment. Finally, we discuss the current status of patient selection for cytoreduction and future directions of intraperitoneal chemotherapy.

The importance of integrating diagnostic modalities in patient selection for CRS-HIPEC in colorectal peritoneal metastases

BACKGROUND

Despite thorough preoperative work-up for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC), so called open-close (OC) procedures as a result of irresectable disease remain common. Currently, diagnostic laparoscopy (DLS) is considered the gold standard, and consequently overrules the results of computed tomography (CT) scans; however, certain regions of the abdomen are difficult to assess and postoperative adhesion formation may further compromise staging during DLS.

PURPOSE

To determine whether better clinical assessment could be achieved by combining the results of DLS and preoperative CT scans during a multidisciplinary team (MDT) meeting.

MATERIAL AND METHODS

All patients who were eligible for CRS-HIPEC after DLS, but eventually underwent an OC procedure between 2010 and 2018 were selected. Radiological reassessment of CT scans was performed and combined with assessment of the DLS during a MDT meeting. The MDT was blinded for the outcome of the procedure (OC vs. CRS-HIPEC).

RESULTS

The majority of the OC procedures (69%) was correctly predicted by the MDT. In most patients (88%), this conclusion was based on the combination of the radiological and surgical peritoneal cancer index (PCI). CT was particularly accurate for detection of larger tumor deposits in the abdominal regions, as 84%-86% was detected. Assessment of lesions in the small bowel regions is troublesome; 72% of lesions are missed on the preoperative CT scan.

CONCLUSIONS

A combination of radiological and surgical assessment of the PCI may lead to improved preoperative patient selection for CRS-HIPEC.

Role of Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy in the Management of Colorectal Peritoneal Metastases

Peritoneal metastases from colon cancer are a particularly challenging disease process given the limited response to systemic chemotherapy. In patients with isolated peritoneal metastases, cytoreductive surgery with hyperthermic intraperitoneal chemotherapy offers a potential treatment option to these patients with limited peritoneal metastases as long as a complete cytoreduction is achieved. Decision about a patient's candidacy for this treatment modality should be undertaken by a multidisciplinary group at expert centers.

External validation of prognostic scores and comparison of predictive accuracy for patients with colorectal cancer with peritoneal metastases considered for cytoreductive surgery and intraperitoneal chemotherapy

BACKGROUND AND OBJECTIVES

Prognostic scores are developed to facilitate the selection of patients with colorectal cancer peritoneal metastases (CRPM) for treatment with cytoreductive surgery (CRS) ± intraperitoneal chemotherapy (IPC). Three prominent prognostic scores are the Peritoneal Surface Disease Severity Score (PSDSS), the Colorectal Peritoneal Metastases Prognostic Surgical Score (COMPASS), and the modified COloREctal-Pc (mCOREP). We externally validate these scores and compare their predictive accuracy.

METHODS

Data from consecutive CRPM patients who underwent CRS/IPC from 1996 to 2018 was used to externally validate COMPASS, PSDSS, and mCOREP. Analysis evaluated the efficacy of each score in predicting (1) open-close laparotomy-those found at laparotomy to not be eligible for curative intent CRS/IPC, (2) surgical futility-those who underwent open-close laparotomy, palliative debulking surgery, or had an overall survival of less than 12 months, and (3) overall and recurrence-free survival (OS, RFS).

RESULTS

Prognostic scores were calculated for the 174-patient external validation cohort. COMPASS was most accurate in predicting open-close laparotomy, futile surgery, and survival (OS and RFS). Area under the curve (AUC) for open-close prediction was 0.78 (95% confidence interval, CI: 0.68-0.87), representing useful discrimination. However, AUC for futility prediction was 0.62 (95% CI: 0.52-0.71), and C-statistic for OS was 0.65 indicating only possibly helpful discrimination. C-statistic for RFS was 0.59 indicating poor discrimination.

CONCLUSION

While COMPASS showed the best statistical behavior, accuracy for several clinically relevant outcomes remains low, and thus applicability to clinical practice limited.

Diagnostic Accuracy of Abdominal CT for Locally Advanced Colon Tumors: Can We Really Entrust Certain Decisions to the Reliability of CT?

Many different options of neoadjuvant treatments for advanced colon cancer are emerging. An accurate preoperative staging is crucial to select the most appropriate treatment option. A retrospective study was carried out on a national series of operated patients with T4 tumors. Considering the anatomo-pathological analysis of the surgical specimen as the gold standard, a diagnostic accuracy study was carried out on the variables T and N staging and the presence of peritoneal metastases (M1c). The parameters calculated were sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios, as well as the overall accuracy. A total of 50 centers participated in the study in which 1950 patients were analyzed. The sensitivity of CT for correct staging of T4 colon tumors was 57%. Regarding N staging, the overall accuracy was 63%, with a sensitivity of 64% and a specificity of 62%; however, the positive and negative likelihood ratios were 1.7 and 0.58, respectively. For the diagnosis of peritoneal metastases, the accuracy was 94.8%, with a sensitivity of 40% and specificity of 98%; in the case of peritoneal metastases, the positive and negative likelihood ratios were 24.4 and 0.61, respectively. The diagnostic accuracy of CT in the setting of advanced colon cancer still has some shortcomings for accurate diagnosis of stage T4, correct classification of lymph nodes, and preoperative detection of peritoneal metastases.

Primary and secondary tumors of the peritoneum: key imaging features and differential diagnosis with surgical and pathological correlation

Peritoneal malignancies represent a diagnostic challenge for abdominal radiologists, oncologists, surgeons and pathologists in multidisciplinary teams, who must address their differential diagnosis, staging and treatment. In this article, we explain the pathophysiology of these processes and lay out the role of different imaging techniques in their evaluation. Then, we review the clinical and epidemiological aspects, the main radiological features and the therapeutic approaches for each primary and secondary peritoneal neoplasm, with surgical and pathological correlation. We further describe other rare peritoneal tumors of uncertain origin and a variety of entities that may mimic peritoneal malignancy. Finally, we summarize the key imaging findings of each peritoneal neoplasm to facilitate an accurate differential diagnosis that may impact patient management.Clinical relevance statementImaging plays an essential role in the evaluation of peritoneal malignancies, assessing their extension, detecting unfavorable sites of involvement and facilitating an accurate differential diagnosis, helping to choose the best therapeutic approach.

Radiologic staging of peritoneal and retroperitoneal disease

Peritoneal and retroperitoneal tumors consist of a heterogenous group of benign and malignant lesions of different origin. Due to often complex multidisciplinary treatment concepts in patients with peritoneal surface malignancies radiological imaging plays a pivotal role regarding the therapeutic options. Moreover, tumor entity, abdominal tumor distribution and common as well as rare differential diagnoses have to be taken into account. Using different radiological modalities non-invasive pretherapeutic diagnostics might be significantly improved. KEY POINTS::   · Diagnostic CT is a valuable part of the initial diagnostic approach to peritoneal surface malignancies.. · Sensitivity might be increased by the additional use of dwMRI and PET/CT considering tumor entity and individual diagnostic issues.. · The Peritoneal Cancer Index (PCI) should be determined independent of radiologic modality.. CITATION FORMAT: · Glockzin G, Helmberger T. Radiologic staging of peritoneal and retroperitoneal disease. Fortschr Röntgenstr 2023; DOI: 10.1055/a-1999-7057.

The Landmark Series: Scoring Systems for Primary Peritoneal Surface Malignancy

BACKGROUND

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) represents an innovative approach to treat or prevent peritoneal metastasis. However, given the morbidity that can be associated with this procedure, adequate patient selection facilitated by scoring systems for primary peritoneal surface malignancy (PSM) is paramount to ensure equitable morbidity as well as acceptable survival outcome.

METHODS

Seminal studies on scoring systems for PSM that have laid the foundation for adequate patient selection and prognostication are spotlighted.

RESULTS

Quantitative prognostic indicators have been defined for patients with PSM that enable the surgeon to make sound clinical judgements as to who may or may not benefit from CRS/HIPEC. These prognostic indicators include the histopathology of the tumor, findings on the preoperative abdominal and pelvic computerized axial tomography, the Peritoneal Cancer Index, completeness of cytoreduction score, and prior surgical score.

CONCLUSIONS

Scoring systems for primary peritoneal surface malignancy reviewed in this article highlight the utility of these systems for patient selection for CRS/HIPEC and prognostication.

Impact of centralization of care for malignant peritoneal mesothelioma: A historical cohort study from the Dutch mesothelioma expert centers

BACKGROUND

Malignant peritoneal mesothelioma (MPM) is a rare and aggressive cancer that has a poor prognosis. An earlier population-based study found that the majority of Dutch patients do not receive anti-cancer treatment. In 2015, Dutch Malignant Mesothelioma care was centralized in two expert centers. We reviewed treatment patterns at these centers, to assess the impact of centralization of MPM care in the Netherlands.

METHODS

Data from all patients referred to the Dutch MPM expert centers from 2014 to 2020, were retrospectively collected. Descriptive statistics regarding referrals, patient and tumor characteristics, and treatment patterns were provided. Population-based incidence rates were provided by the Netherlands Cancer Registry.

RESULTS

From 2014 to 2020, 78 patients were referred to the Dutch Mesothelioma expert centers, of whom 32 were female (41%). From 2014 to 2017, 27 patients were referred, whereas 51 patients were referred from 2018 to 2020. This represents about 24% and 61% of the estimated population incidence, respectively. Treatment patterns were comparable between both periods. Between 2014 and 2018, 33% of patients underwent surgery, 44% systemic therapy, and 22% received best supportive care (BSC), while this was 29%, 37%, and 33% respectively from 2018 to 2020.

CONCLUSION

Centralization of care for patients with MPM resulted in an increase of annual referrals to the Dutch mesothelioma expert centers. While population-based incidence did not change during the study period, the absolute number of patients receiving treatment at our centers did increase. This might be considered a first important step towards better treatment for patients with this fatal disease.

Clinical outcomes of curative surgical resection of peritoneal metastasis in patients with colorectal cancer: A long-term follow-up study

INTRODUCTION

Colorectal cancer with peritoneal metastasis (PM) has been considered a non-curative disease. PM is associated with reduced overall survival (OS) and worse prognosis compared with metastasis at other sites. We aimed to investigate the treatment outcome and recurrence after curative resection of colorectal PM during a long-term follow-up.

METHODS

Patients who were diagnosed with colorectal PM and underwent surgery between December 2001 and December 2019 were included (n = 309). Curative resection was defined as PM resection without residual disease after surgery (complete macroscopic resection).

RESULTS

Of 309 patients, 208 (67.8%) had PM as an initially metastatic disease. Curative (R0/1) resection was achieved in 155 (50.2%) patients, while non-curative operation (R2 resection or palliative operation including colostomy) was performed in 154 (49.8%) patients. Compared with patients who underwent non-curative operation, those with curative resection more often had a single PM on preoperative imaging (34.2% vs. 20.8%, p = 0.011) and postoperative results (59.4% vs. 22.7%, p < 0.001) and less often had concurrent metastasis (distant lymph node, liver, or lung) at the time of surgery (p < 0.001). During a median follow-up of 90.4 months, 80.6% (125/155) patients had recurrence in the curative resection group; the peritoneum was the most common site (56.0%). The median OS was 47.7 months (95% CI, 39.2-56.2) in the curative resection group and 24.8 months (95% CI, 20.8-28.9) in the non-curative resection group, respectively (p < 0.001). In particular, twenty-six patients without recurrence showed long-term survival after curative resection (median OS, 87.1 months; range, 40.1-127.5).

CONCLUSION

Surgical resection can be considered for selected patients with colorectal PM because a significant number of them could seize the cure changes during their treatment continuum.

A Prediction Model Intended for Exploratory Laparoscopy Risk Stratification in Colorectal Cancer Patients With Potential Occult Peritoneal Metastasis

BACKGROUND

The early diagnosis of occult peritoneal metastasis (PM) remains a challenge due to the low sensitivity on computed tomography (CT) images. Exploratory laparoscopy is the gold standard to confirm PM but should only be proposed in selected patients due to its invasiveness, high cost, and port-site metastasis risk. In this study, we aimed to develop an individualized prediction model to identify occult PM status and determine optimal candidates for exploratory laparoscopy.

METHOD

A total of 622 colorectal cancer (CRC) patients from 2 centers were divided into training and external validation cohorts. All patients' PM status was first detected as negative on CT imaging but later confirmed by exploratory laparoscopy. Multivariate analysis was used to identify independent predictors, which were used to build a prediction model for identifying occult PM in CRC. The concordance index (C-index), calibration plot and decision curve analysis were used to evaluate its predictive accuracy and clinical utility.

RESULTS

The C-indices of the model in the development and validation groups were 0.850 (95% CI 0.815-0.885) and 0.794 (95% CI, 0.690-0.899), respectively. The calibration curve showed consistency between the observed and predicted probabilities. The decision curve analysis indicated that the prediction model has a great clinical value between thresholds of 0.10 and 0.72. At a risk threshold of 30%, a total of 40% of exploratory laparoscopies could have been prevented, while still identifying 76.7% of clinically occult PM cases. A dynamic online platform was also developed to facilitate the usage of the proposed model.

CONCLUSIONS

Our individualized risk model could reduce the number of unnecessary exploratory laparoscopies while maintaining a high rate of diagnosis of clinically occult PM. These results warrant further validation in prospective studies.

CLINICAL TRIAL REGISTRATION

https://www.isrctn.com, identifier ISRCTN76852032.

Prediction of Metachronous Peritoneal Metastases After Radical Surgery for Colon Cancer: A Scoring System Obtained from an International Multicenter Cohort

Background

Since novel strategies for prevention and treatment of metachronous peritoneal metastases (mPM) are under study, it appears crucial to identify their risk factors. Our aim is to establish the incidence of mPM after surgery for colon cancer (CC) and to build a statistical model to predict the risk of recurrence.

Patients and Methods

Retrospective analysis of consecutive pT3–4 CC operated at five referral centers (2014–2018). Patients who developed mPM were compared with patients who were PM-free at follow-up. A scoring system was built on the basis of a logistic regression model.

Results

Of the 1423 included patients, 74 (5.2%) developed mPM. Patients in the PM group presented higher preoperative carcinoembryonic antigen (CEA) [median (IQR): 4.5 (2.5–13.0) vs. 2.7 (1.5–5.9), P = 0.001] and CA 19-9 [median (IQR): 17.7 (12.0–37.0) vs. 10.8 (5.0–21.0), P = 0.001], advanced disease (pT4a 42.6% vs. 13.5%; pT4b 16.2% vs. 3.2%; P < 0.001), and negative pathological characteristics. Multivariate logistic regression identified CA 19-9, pT stage, pN stage, extent of lymphadenectomy, and lymphovascular invasion as significant predictors, and individual risk scores were calculated for each patient. The risk of recurrence increased remarkably with score values, and the model demonstrated a high negative predictive value (98.8%) and accuracy (83.9%) for scores below five.

Conclusions

Besides confirming incidence and risk factors for mPM, our study developed a useful clinical tool for prediction of mPM risk. After external validation, this scoring system may guide personalized decision-making for patients with locally advanced CC.

Supplementary Information

The online version contains supplementary material available at 10.1245/s10434-022-12097-9.

Prospective Comparison of the Performance of MRI Versus CT in the Detection and Evaluation of Peritoneal Surface Malignancies

Background: The performance of MRI versus CT in the detection and evaluation of peritoneal surface malignancies (PSM) remains unclear in the current literature. Our study is the first prospective study in an Asian center comparing the two imaging modalities, validated against intra-operative findings. Methods: A total of 36 patients with PSM eligible for CRS-HIPEC underwent both MRI and CT scans up to 6 weeks before the operation. The scans were assessed for the presence and distribution of PSM and scored using the peritoneal cancer index (PCI), which were compared against PCI determined at surgery. Results: Both MRI and CT were 100% sensitive and specific in detecting the overall presence of PSM. Across all peritoneal regions, the sensitivity and specificity for PSM detection was 49.1% and 93.0% for MRI, compared to 47.8% and 95.1% for CT (p = 0.76). MRI was more sensitive than CT for small bowel disease, although the difference did not reach statistical significance. Comparing PCI on imaging with intra-operative PCI, the mean difference was found to be −3.4 ± 5.4 (p < 0.01) for MRI, and −3.9 ± 4.1 (p < 0.01) for CT. The correlation between imaging and intra-operative PCI was poor, with a concordance coefficient of 0.76 and 0.79 for MRI and CT, respectively. Within individual peritoneal regions, there was also poor agreement between imaging and intra-operative PCI for both modalities, other than in regions 1 and 3. Conclusion: MRI and CT are comparable in the detection and evaluation of PSM. While sensitive in the overall detection of PSM, they are likely to underestimate the true disease burden.

Synopsis of a clinical practice guideline for pancreatic ductal adenocarcinoma with peritoneal dissemination in Japan; Japan Peritoneal Malignancy Study Group

Patients with pancreatic ductal adenocarcinoma (PDAC) with peritoneal dissemination have a dismal prognosis because discontinuation of systemic chemotherapy is required for massive ascites or poor performance status. The natural history, diagnosis and treatment of PDAC with peritoneal dissemination have not been fully investigated. We systematically reviewed published information on the clinical diagnosis and treatment of PDAC with peritoneal dissemination using the PubMed database (2000-2020) and provided recommendations in response to clinical questions. This guideline was created according to the "Minds Clinical Practice Guideline Development Guide 2017". The literature quality and body of evidence were evaluated with the GRADE System and classified into four levels ("strong", "medium", "weak", "very weak"). The strength of each final recommendation was decided by a vote of committee members based on the GRADE Grid method. These guidelines address three subjects: diagnostic, chemotherapeutic, and surgical approaches. They include nine clinical questions and statements with recommendation strengths, evidence levels, and agreement rates, in addition to one "column". This is the English synopsis of the 2021 Japanese clinical practice guideline for PDAC with peritoneal dissemination. It summarizes the clinical evidence for the diagnosis and treatment of PDAC with peritoneal dissemination and provides future perspectives.

GECOP-MMC: phase IV randomized clinical trial to evaluate the efficacy of hyperthermic intraperitoneal chemotherapy (HIPEC) with mytomicin-C after complete surgical cytoreduction in patients with colon cancer peritoneal metastases

BACKGROUND

The French PRODIGE 7 trial, published on January 2021, has raised doubts about the specific survival benefit provided by HIPEC with oxaliplatin 460 mg/m² (30 minutes) for the treatment of peritoneal metastases from colorectal cancer. However, several methodological flaws have been identified in PRODIGE 7, specially the HIPEC protocol or the choice of overall survival as the main endpoint, so its results have not been assumed as definitive, emphasizing the need for further research on HIPEC. It seems that the HIPEC protocol with high-dose mytomicin-C (35 mg/m²) is the preferred regime to evaluate in future clinical studies.

METHODS

GECOP-MMC is a prospective, open-label, randomized, multicenter phase IV clinical trial that aims to evaluate the effectiveness of HIPEC with high-dose mytomicin-C in preventing the development of peritoneal recurrence in patients with limited peritoneal metastasis from colon cancer (not rectal), after complete surgical cytoreduction. This study will be performed in 31 Spanish HIPEC centres, starting in March 2022. Additional international recruiting centres are under consideration. Two hundred sixteen patients with PCI ≤ 20, in which complete cytoreduction (CCS 0) has been obtained, will be randomized intraoperatively to arm 1 (with HIPEC) or arm 2 (without HIPEC). We will stratified randomization by surgical PCI (1-10; 11-15; 16-20). Patients in both arms will be treated with personalized systemic chemotherapy. Primary endpoint is peritoneal recurrence-free survival at 3 years. An ancillary study will evaluate the correlation between surgical and pathological PCI, comparing their respective prognostic values.

DISCUSSION

HIPEC with high-dose mytomicin-C, in patients with limited (PCI ≤ 20) and completely resected (CCS 0) peritoneal metastases, is assumed to reduce the expected risk of peritoneal recurrence from 50 to 30% at 3 years.

TRIAL REGISTRATION

EudraCT number: 2019-004679-37; Clinicaltrials.gov: NCT05250648 (registration date 02/22/2022, ).

The role of imaging in diagnosis and management of malignant peritoneal mesothelioma: a systematic review

PURPOSE

Imaging of the peritoneum and related pathology is a challenge. Among peritoneal diseases, malignant peritoneal mesothelioma (MPeM) is an uncommon tumor with poor prognosis. To date, there are no specific guidelines or imaging protocols dedicated for the peritoneum and MPeM. The objective of this study was to analyze the literature describing imaging modalities used for MPeM to determine their relative clinical efficacy and review commonly reported imaging features of MPeM to promote standardized reporting.

METHODS

We performed a systematic review of original research articles discussing imaging modalities in MPeM from 1999 to 2020. Effectiveness measures and common findings were compared across imaging modalities.

RESULTS

Among 582 studies analyzed, the most-used imaging modality was CT (54.3%). In the differentiation of MPeM from peritoneal carcinomatosis, one study found CT had a diagnostic sensitivity of 53%, specificity of 100%, and accuracy of 68%. Two studies found fluorodeoxyglucose positron emission tomography (FDG-PET) had sensitivity of 86-92%, specificity of 83-89%, and accuracy of 87-89%. Another study found magnetic resonance imaging (MRI) was the best predictor of the peritoneal carcinomatosis index. Characteristics shown to best differentiate MPeM from other diseases included ascites, peritoneal thickening, mesenteric thickening, pleural plaques, maximum tumor dimension, and number of masses.

CONCLUSION

Most published MPeM imaging studies utilized CT. PET/CT or MRI appear promising, and future studies should compare effectiveness of these modalities. MPeM imaging reports should highlight ascites, number of and maximum tumor dimension, peritoneal/mesenteric thickening, and associated pleural plaques, allowing for better aggregation of MPeM imaging data across studies.

Peritoneal malignancy: anatomy, pathophysiology and an update on modern day imaging

With increasing subspecialised experience in radical cytoreductive surgery and intra-abdominal chemotherapy for peritoneal malignancy, outcomes have improved significantly in selected patients. The surgery and the treatment regimens are radical and therefore correct patient selection is critical. The radiologist plays a central role in this process by estimating, as precisely as possible, the pre-treatment disease burden. Because of the nature of the disease process, accurate staging is not an easy task. Tumour deposits may be very small and in locations where they are very difficult to detect. It must be acknowledged that no form of modern day imaging has the capability of detecting the smallest peritoneal nodules, which may only be visible to direct inspection or histopathological evaluation. Nonetheless, it behoves the radiologist to be as exact and precise as possible in the reporting of this disease process. This is both to select patients who are likely to benefit from radical treatment, and just as importantly, to identify patients who are unlikely to achieve adequate cytoreductive outcomes. In this review, we outline the patterns of spread of disease and the anatomic basis for this, as well as the essential aspects of reporting abdominal studies in this patient group. We provide an evidence-based update on the relative strengths and limitations of our available multimodality imaging techniques namely CT, MRI and positron emission tomography/CT.

Surgical Dilemmas Associated with Malignant Large Bowel Obstructions

Despite an increase in screening colonoscopy, with the objective to decrease the incidence of colorectal cancer, a third of patients will present with an obstructing cancer. Malignant large bowel obstructions (MLBO) pose a challenging workup and treatment paradigm where an oncologic primary tumor resection must be balanced with relieving the obstruction, functional outcomes, palliation, and consideration for adjuvant therapy. A thorough work up with cross-sectional imaging and medical optimization should be attempted; however, patients may present in extremis and require emergent intervention. The onset of MLBO can be insidious, but result in electrolyte derangements, perforation, small bowel obstruction, hemorrhage, and ischemia. Self-expandable metallic stents have been used as palliation or as a bridge to surgery and have allowed for minimally invasive surgical options as well as a decrease in stoma rates. Patients with signs of colon ischemia or perforation require emergent surgery, which is associated with an increase in stoma formation, morbidity, mortality, and a decrease in overall survival.

Prediction of Peritoneal Cancer Index and Prognosis in Peritoneal Metastasis of Gastric Cancer Using NLR-PLR-DDI Score: A Retrospective Study

OBJECTIVE

The peritoneal cancer index (PCI) is used to evaluate the peritoneal metastasis of gastric cancer. A higher value indicates more widespread and/or larger tumors in the peritoneal cavity. The neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) are representative blood markers of systemic inflammatory responses, and D-dimer (DDI) is the final stable product of fibrin. This study explores the association of NLR, PLR, and DDI with PCI and assesses the clinical utility of a new blood score combining the NLR, PLR, and DDI (NPD score) for PCI and the prognosis prediction of gastric cancer.

METHODS

This was a single-center, nonrandomized, retrospective, cohort study. We evaluated the risk factors for high PCI (≥15) using univariate and multivariate analyses. According to the findings of the ROC analysis, we determined the cut-off values of NLR, PLR and DDI and created the NPD score. The patients were grouped into high-risk and low-risk groups based on their NPD score (<2 and ≥2, respectively).

RESULTS

Univariate and multivariate analysis demonstrated that the NLR, PLR, and DDI were independent risk factors for high PCI (P < 0.05). The NPD score of the high-risk group was ≥2, and the NPD score of the low-risk group was <2. The median survival time was 14.2 in the high-risk group and 25.6 in the low-risk group. The NPD score was significantly higher in the high-PCI group than that in the low-PCI group. The survival of the high-risk group was significantly worse than that of the low-risk group (P = 0.003). NPD score decrease was an independent predictive factor for PCI decrease.

CONCLUSION

NLR, PLR, and DDI are potential independent risk factors for high PCI in patients with peritoneal metastasis of gastric cancer. The NPD scoring system can help in predicting PCI and the prognosis of patients with peritoneal metastasis of gastric cancer.

The Landmark Series: Appendiceal Primary Peritoneal Surface Malignancy

Appendiceal primary peritoneal surface malignancies are rare and include a broad spectrum of pathologies ranging from indolent disease to aggressive disease. As such, the data that drive the management of appendiceal peritoneal surface malignancies is generally not based on prospective clinical trial data, but rather consists of level 1 data based on retrospective studies and high-volume institutional experiences. Complete surgical debulking typically offers the best chance for long-term survival. This review highlights the landmark articles on which management of primary appendiceal peritoneal surface malignancies are based.

Safety and Clinical Value of Prophylactic Ureteral Stenting Before Cytoreductive Surgery With Hyperthermic Intraperitoneal Chemotherapy

BACKGROUND

Prophylactic ureteral stents (PUS) are typically placed prior to complex abdominal or pelvic operations at the surgeon's discretion to help facilitate detection of iatrogenic ureteral injury. However, its usefulness and safety in the setting of cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) have not been examined. This study aims to evaluate the potential clinical value and risk profile of prophylactic ureteral stent placement prior to CRS-HIPEC.

METHODS

We performed a single-institutional retrospective analysis of 145 patients who underwent CRS-HIPEC from 2013 to 2021. Demographic and operative characteristics were compared between patients who underwent PUS placement and those that did not. Ureteral stent-related complications were evaluated.

RESULTS

Of the 145 patients included in the analysis, 124 underwent PUS placement. There were no significant differences in patient demographics, medical comorbidities, or tumor characteristics. Additionally, PUS placement did not significantly increase operative time and was not associated with increased pelvic organ resection. However, patients who underwent prophylactic ureteral stenting had significantly higher peritoneal carcinomatosis index score (15.1 vs 9.1, P=.002) and increased rate of ureteral complications (24.2% vs 14.3%, P=.04), which led to lengthened hospital stay (13.2 days vs 8.1 days, P= .03). Notably, the sole ureteral injury and three cases of hydronephrosis were seen in patients who underwent PUS.

CONCLUSION

Prophylactic ureteral stent placement in patients undergoing CRS-HIPEC may be useful, particularly in patients with predetermined extensive pelvic disease. However, PUS placement is not without potential morbidity and should be selectively considered in patients for whom benefits outweigh the risks.

Imaging of Gastric Carcinomatosis

Diagnosing the absence or presence of peritoneal carcinomatosis in patients with gastric cancer, including its extent and distribution, is an essential step in patients' therapeutic management. Such diagnosis still remains a radiological challenge. In this article, we review the strengths and weaknesses of the different imaging techniques for the diagnosis of peritoneal carcinomatosis of gastric origin as well as the techniques' imaging features. We also discuss the assessment of response to treatment and present recommendations for the follow-up of patients with complete surgical resection according to the presence of risk factors of recurrence, as well as discussing future directions for imaging improvement.

ESGO/ISUOG/IOTA/ESGE Consensus Statement on preoperative diagnosis of ovarian tumors

The European Society of Gynaecological Oncology (ESGO), the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG), the International Ovarian Tumour Analysis (IOTA) group and the European Society for Gynaecological Endoscopy (ESGE) jointly developed clinically relevant and evidence-based statements on the preoperative diagnosis of ovarian tumors, including imaging techniques, biomarkers and prediction models. ESGO/ISUOG/IOTA/ESGE nominated a multidisciplinary international group, including expert practising clinicians and researchers who have demonstrated leadership and expertise in the preoperative diagnosis of ovarian tumors and management of patients with ovarian cancer (19 experts across Europe). A patient representative was also included in the group. To ensure that the statements were evidence-based, the current literature was reviewed and critically appraised. Preliminary statements were drafted based on the review of the relevant literature. During a conference call, the whole group discussed each preliminary statement and a first round of voting was carried out. Statements were removed when consensus among group members was not obtained. The voters had the opportunity to provide comments/suggestions with their votes. The statements were then revised accordingly. Another round of voting was carried out according to the same rules to allow the whole group to evaluate the revised version of the statements. The group achieved consensus on 18 statements. This Consensus Statement presents these ESGO/ISUOG/IOTA/ESGE statements on the preoperative diagnosis of ovarian tumors and the assessment of carcinomatosis, together with a summary of the evidence supporting each statement.

ESGO/ISUOG/IOTA/ESGE Consensus Statement on pre-operative diagnosis of ovarian tumors

The European Society of Gynaecological Oncology (ESGO), the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG), the International Ovarian Tumour Analysis (IOTA) group, and the European Society for Gynaecological Endoscopy (ESGE) jointly developed clinically relevant and evidence-based statements on the pre-operative diagnosis of ovarian tumors, including imaging techniques, biomarkers, and prediction models. ESGO/ISUOG/IOTA/ESGE nominated a multidisciplinary international group, including expert practising clinicians and researchers who have demonstrated leadership and expertise in the pre-operative diagnosis of ovarian tumors and management of patients with ovarian cancer (19 experts across Europe). A patient representative was also included in the group. To ensure that the statements were evidence-based, the current literature was reviewed and critically appraised. Preliminary statements were drafted based on the review of the relevant literature. During a conference call, the whole group discussed each preliminary statement and a first round of voting was carried out. Statements were removed when a consensus among group members was not obtained. The voters had the opportunity to provide comments/suggestions with their votes. The statements were then revised accordingly. Another round of voting was carried out according to the same rules to allow the whole group to evaluate the revised version of the statements. The group achieved consensus on 18 statements. This Consensus Statement presents these ESGO/ISUOG/IOTA/ESGE statements on the pre-operative diagnosis of ovarian tumors and the assessment of carcinomatosis, together with a summary of the evidence supporting each statement.

ESGO/ISUOG/IOTA/ESGE Consensus Statement on preoperative diagnosis of ovarian tumours

The European Society of Gynaecological Oncology (ESGO), the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG), the International Ovarian Tumour Analysis (IOTA) group and the European Society for Gynaecological Endoscopy (ESGE) jointly developed clinically relevant and evidence-based statements on the preoperative diagnosis of ovarian tumours, including imaging techniques, biomarkers and prediction models. ESGO/ISUOG/IOTA/ESGE nominated a multidisciplinary international group, including expert practising clinicians and researchers who have demonstrated leadership and expertise in the preoperative diagnosis of ovarian tumours and management of patients with ovarian cancer (19 experts across Europe). A patient representative was also included in the group. To ensure that the statements were evidence-based, the current literature was reviewed and critically appraised. Preliminary statements were drafted based on the review of the relevant literature. During a conference call, the whole group discussed each preliminary statement and a first round of voting was carried out. Statements were removed when a consensus among group members was not obtained. The voters had the opportunity to provide comments/suggestions with their votes. The statements were then revised accordingly. Another round of voting was carried out according to the same rules to allow the whole group to evaluate the revised version of the statements. The group achieved consensus on 18 statements. This Consensus Statement presents these ESGO/ISUOG/IOTA/ESGE statements on the preoperative diagnosis of ovarian tumours and the assessment of carcinomatosis, together with a summary of the evidence supporting each statement.

Dedicated MRI staging versus surgical staging of peritoneal metastases in colorectal cancer patients considered for CRS-HIPEC; the DISCO randomized multicenter trial

Background

Selecting patients with peritoneal metastases from colorectal cancer (CRCPM) who might benefit from cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is challenging. Computed tomography generally underestimates the peritoneal tumor load. Diagnostic laparoscopy is often used to determine whether patients are amenable for surgery. Magnetic resonance imaging (MRI) has shown to be accurate in predicting completeness of CRS. The aim of this study is to determine whether MRI can effectively reduce the need for surgical staging.

Methods

The study is designed as a multicenter randomized controlled trial (RCT) of colorectal cancer patients who are deemed eligible for CRS-HIPEC after conventional CT staging. Patients are randomly assigned to either MRI based staging (arm A) or to standard surgical staging with or without laparoscopy (arm B). In arm A, MRI assessment will determine whether patients are eligible for CRS-HIPEC. In borderline cases, an additional diagnostic laparoscopy is advised. The primary outcome is the number of unnecessary surgical procedures in both arms defined as: all surgeries in patients with definitely inoperable disease (PCI > 24) or explorative surgeries in patients with limited disease (PCI < 15). Secondary outcomes include correlations between surgical findings and MRI findings, cost-effectiveness, and quality of life (QOL) analysis.

Conclusion

This randomized trial determines whether MRI can effectively replace surgical staging in patients with CRCPM considered for CRS-HIPEC.

Trial registration

Registered in the clinical trials registry of U.S. National Library of Medicine under NCT04231175.

Current Status and Recent Update of Imaging Evaluation for Peri-Hilar Cholangiocarcinoma

간문주변부의 해부학적 복잡성으로 인해 간문주변부 담관암은 그 진단과 치료가 어려운 질환으로 알려져 있다. 간문주변부 담관암이 의심되는 환자에 있어서, 영상 검사는 이상 소견의 발견 및 감별 진단, 종양의 종축 침범 부위의 파악, 인접 혈관 침범과 원격 전이 유무의 파악, 그리고 최종적으로 수술적 절제 가능 유무의 평가에 있어 핵심적인 역할을 하고 있다. 이 종설에서는 간문주변부 담관암의 분류 및 종양의 평가를 위해 권고되는 표준 영상 검사의 기법과 간문주변부 담관암의 전형적인 영상 소견에 대해 기술할 예정이다. 종축 방향의 종양 침범 파악, 인접 혈관 침범 및 원격 전이 유무의 평가에 있어서 각 영상 검사 소견과 그 진단능에 대해 논의할 예정이다. 이후 전통적인 절제 가능성 평가의 개념에 대해 고찰하고, 최근의 경향을 소개한다.

Intraperitoneal Paclitaxel Combined with S-1 Plus Oxaliplatin for Advanced Gastric Cancer with Peritoneal Metastasis: a Phase I Study

Purpose

We designed a new regimen by combining intraperitoneal (IP) paclitaxel (PTX) with systemic S-1 plus oxaliplatin (SOX) for the treatment of advanced gastric cancer with peritoneal metastasis. This dose-escalation study aimed to determine the maximum tolerated dose (MTD) and recommended dose (RD) of IP PTX administered weekly to patients.

Materials and Methods

Eight cycles of IP PTX plus SOX regimen were administered to the patients. S-1 was administered orally twice daily at a dose of 80 mg/m²/day for 14 consecutive days, followed by 7 days of rest. Intravenous oxaliplatin was administered at a fixed dose of 100 mg/m² on day 1, while IP PTX was administered on days 1 and 8. The initial dose of IP PTX was 40 mg/m², and the dose escalation was set in units of 20 mg/m² up to 80 mg/m². Dose-limiting toxicities (DLTs) were defined as grade 3 non-hematologic toxicities, grade 4 leukopenia, grade 3 febrile neutropenia, and grade 3 thrombocytopenia.

Results

Nine patients were included in the study. No DLTs were observed in any of the enrolled patients. Therefore, the MTD was not reached, and the RD of IP PTX was determined to be 80 mg/m². Four patients (44%) showed a decreased peritoneal cancer index score on second-look laparoscopic examination.

Conclusions

The present study determined the dose for further clinical trials of IP PTX to be 80 mg/m², when combined with a systemic SOX regimen.

Prospective correlation of the radiological, surgical and pathological findings in patients undergoing cytoreductive surgery for colorectal peritoneal metastases: implications for the preoperative estimation of the peritoneal cancer index

AIM

The peritoneal cancer index (PCI) is one of the strongest prognostic factors in patients undergoing cytoreductive surgery (CRS) for colorectal peritoneal metastases. Using pathological evaluation, however, the disease extent differs in a large proportion of patients. Our aim was to study the correlation between the radiological (rPCI), surgical (sPCI) and pathological (pPCI) PCI in order to determine factors affecting the discordance between these indices and their potential therapeutic implications.

METHOD

From July 2018 to December 2019, 128 patients were included in this study. The radiological, pathological and surgical findings were compared. A protocol for pathological evaluation was followed at all centres.

RESULTS

All patients underwent a CT scan and 102 (79.6%) had a peritoneal MRI. The rPCI was the same as the sPCI in 81 (63.2%) patients and the pPCI in 93 (72.6%). Concordance was significantly lower for moderate-volume (sPCI 13-20) and high-volume (sPCI > 20) disease than for low-volume disease (sPCI 0-12) (P < 0.001 for sPCI; P = 0.001 for pPCI). The accuracy of imaging in predicting presence/absence of disease upon pathological evaluation ranged from 63% to 97% in the different regions of the PCI. The pPCI concurred with the sPCI in 86 (68.8%) patients. Of the nine patients with sPCI > 20, the pPCI was less than 20 in six.

CONCLUSION

The rPCI and sPCI both concurred with pPCI in approximately two thirds of patients. Preoperative evaluation should focus on the range in which the sPCI lies and not its absolute value. Radiological evaluation did not overestimate sPCI in any patient with high/moderate-volume disease. The benefit of CRS in patients with a high r/sPCI (> 20) who respond to systemic therapies should be prospectively evaluated.

Metastatic Colorectal Cancers with Mismatch Repair Deficiency Result in Worse Survival Regardless of Peritoneal Metastases

BACKGROUND

Mismatch-repair deficiency (dMMR) predicts worse chemoresponsiveness but better survival in early-stage colorectal adenocarcinoma. This study examined metastatic colorectal and appendix cancers with and without peritoneal metastasis (PM) in the National Cancer Database (NCDB), hypothesizing that dMMR tumors show better survival.

METHODS

Stage 4 colon, rectum, and appendix cancers (2010-2016) were identified in the NCDB (including goblet cell carcinoids, excluding neuroendocrine tumors). Stage 4 disease without liver, bone, brain, lung, or distant nodal metastases defined PM. Fisher's exact tests were used to compare proportions, and Kaplan-Meier analysis was used to evaluate survival.

RESULTS

Of 130,125 stage 4 colon, rectum, and appendix cancers, 27,848 (21.4%) had PM. Appendix primary tumors had PM more commonly than colon or rectum cancer (83.6% vs. 20.6% and 12.1% of stage 4 cases; p < 0.0001). More PM patients had MMR testing than patients with other metastasis (OM) (21.4% vs. 16.1%), and testing increased from 9.6% in 2010 to 26.3% in 2016 (both p < 0.0001). Among the PM patients, MMR testing was least common for appendix cancers (9.0%). When tested, PM patients more often had dMMR (22.9% [1122/4900] vs. 15.4% [2532/16,495] of OM patients; p < 0.0001). Colon primary tumor had dMMR most frequently (25.0% vs. 14.6% and 14.5% for rectal and appendix tumor; p < 0.0001). Most PM patients received chemotherapy (66.2%). Immunotherapy use increased over time (1.1% of PM diagnoses in 2010 vs. 20.8% in 2016). For MMR-tested stage 4 patients, dMMR correlated with worse survival (median OM, 19.7 vs. 23.9 months, p < 0.0001; median PM, 19.9 vs. 24.6 months, p = 0.035).

CONCLUSIONS

The NCDB showed dMMR predicting worse survival for stage 4 colorectal cancers with and without PM and dMMR existing in 14.5-25% of tested patients, suggesting that increased attention to MMR testing in stage 4 colorectal and appendix cancers can identify many patients who could potentially benefit from immunotherapy.

Clinical and Radiologic Predictors of a Pathologic Complete Response to Neoadjuvant Chemotherapy (NACT) in Patients Undergoing Cytoreductive Surgery for Colorectal Peritoneal Metastases: Results of a Prospective Multi-center Study

BACKGROUND

Patients undergoing cytoreductive surgery for colorectal peritoneal metastases who have a pathologic complete response (pCR) to neoadjuvant chemotherapy experience a significantly longer survival than those with residual disease. This response is known only after surgery. This study aimed to examine clinical and radiologic predictors of a pCR.

METHODS

From July 2018 to December 2019, the study prospectively enrolled 120 patients. The clinical and radiologic findings were compared between patients with and without a pCR. A protocol for pathologic evaluation was followed.

RESULTS

A pCR was observed in 34 patients (28.3%). Receiver operating characteristic (ROC) curves showed that patients with a surgical Peritoneal Cancer Index (sPCI) of 3 or lower had an 80% probability of experiencing a pCR, and that patients with a radiologic PCI (rPCI) of 2 or lower had a 70% probability of experiencing a pCR. A pCR was correctly predicted for 47% of the patients by imaging and for 44.4% of the patients by surgical evaluation. The site of primary tumor, the timing of peritoneal metastasis (PM), histology, tumor marker positivity, and mutations in known poor prognostic genes (KRAS) did not differ between the patients with and those without pCR. The primary tumor showed residual disease in 23.5% and regional nodes in 26.4% of the patients with pCR.

CONCLUSIONS

The rPCI and sPCI concurred with a pCR in less than 50% of the patients. The patients with a lower PCI had greater concordance. An sPCI of 3 or lower was predictive of a pCR in 80% of the patients. The impact of KRAS mutations on pCR should be evaluated in a larger series. The predictors of pCR and response to systemic chemotherapy should be incorporated in prognostic scores used to select patients for surgery.

Quality analysis of operative reports and referral data for appendiceal neoplasms with peritoneal dissemination

BACKGROUND

Peritoneal metastasis from appendiceal neoplasms is a rare disease usually found unexpectedly and is associated with deficits in quality reporting of findings.

METHODS

Retrospective review of our appendiceal peritoneal metastases carcinomatosis database evaluating quality of index operative and pathology reports. Operative report quality was graded by 2 standards; general quality, based on Royal College of Surgeons quality metrics and peritoneal metastases assessment. Pathology report quality was assessed by the accuracy of diagnosis.

RESULTS

Three hundred and seventy-five index operative reports and 490 outside pathology reports were reviewed. General quality of the index operative reports was excellent, with nearly 80% of reports encompassing all the Royal College of Surgeons quality metrics. Peritoneal metastases assessment was poor. Forty-four percent of the reports performed no peritoneal evaluation, while 48.3% only involved partial peritoneal evaluation. Only 7.7% of the reports performed a complete evaluation. Of the pathology reports, 48.4% had discrepancies with final pathologic findings. Low-grade disease and high-grade disease were misdiagnosed 36.06% and 62.7% of the time, respectively. Discordant treatment occurred in 15.3% and 30.0% of cases for misdiagnosed low-grade and high-grade disease, respectively. Incomplete cytoreduction was attempted in nearly a third of referral cases, which was associated with a significantly increased risk for ultimate incomplete cytoreduction with an odds ratio of 4.72.

CONCLUSION

This review finds that referral operative reports' descriptions of the technical aspects of a procedure is usually complete. However, oncologic parameters and descriptions of peritoneal metastases are frequently incomplete. Further, pathology reports from outside institutions can lead to inappropriate clinical management decisions. We propose a simplified algorithm to assist nonperitoneal surface malignancy surgeons.

Radiologic Evaluation and Structured Reporting Form for Extrahepatic Bile Duct Cancer: 2019 Consensus Recommendations from the Korean Society of Abdominal Radiology

Radiologic imaging is important for evaluating extrahepatic bile duct (EHD) cancers; it is used for staging tumors and evaluating the suitability of surgical resection, as surgery may be contraindicated in some cases regardless of tumor stage. However, the published general recommendations for EHD cancer and recommendations guided by the perspectives of radiologists are limited. The Korean Society of Abdominal Radiology (KSAR) study group for EHD cancer developed key questions and corresponding recommendations for the radiologic evaluation of EHD cancer and organized them into 4 sections: nomenclature and definition, imaging technique, cancer evaluation, and tumor response. A structured reporting form was also developed to allow the progressive accumulation of standardized data, which will facilitate multicenter studies and contribute more evidence for the development of recommendations.

Distribution Characteristics of Colorectal Peritoneal Carcinomatosis Based on the Positron Emission Tomography/Peritoneal Cancer Index

Background: Colorectal peritoneal carcinomatosis (CRPC) is a primary cause of death in colorectal cancer (CRC) patients. In the past, computed tomography (CT) has been the primary method used to evaluate the distribution of CRPC. This study uses ¹⁸F-FDG positron emission tomography/computed tomography (PET/CT) to investigate the distribution characteristics of CRPC. Materials and Methods: The distribution characteristics of 46 patients with CRC who were treated in the authors' hospital were retrospectively analyzed using the peritoneal cancer index (PCI). Results: The 46 patients in the study showed CRPC involvement in 203 of the 598 abdominal and pelvic regions studied (33.9%, 203/598). The regional proportions of CRPC involvement, from high to low, were as follows: region 6 (13.8%), region 0 (10.3%), region 1 (9.9%), region 5 (8.9%), region 7 (8.4%), region 3 (8.4%), region 2 (7.4%), region 4 (7.4%), region 11 (6.9%), region 8 (6.4%), region 12 (5.4%), region 9 (3.4%), and region 10 (3.4%). Thirty-three patients had a PCI of <20, and 13 patients had a PCI of ≥20. Those 13 were among the 17 (37% 17/46) who had CRPC involvement in all three regions. According to the location of the primary CRC focus, the 46 patients were divided into three groups: right hemicolon, left hemicolon, and rectum. The frequency of CRPC was greater in the rectum group than in the left hemicolon group, and the SUV_max of CRPC was greater in the right hemicolon group than in the left hemicolon group; these differences were statistically significant (p < 0.05). Conclusions: The distribution of CRPC has certain characteristics in the abdominal and pelvic cavities. The PET-PCI scores can provide a basis for the diagnosis and clinical treatment strategies in patients with CRC.

Spectral photon-counting CT imaging of colorectal peritoneal metastases: initial experience in rats

Computed tomography imaging plays a major role in the preoperative assessment of tumor burden by providing an accurate mapping of the distribution of peritoneal metastases (PM). Spectral Photon Counting Computed Tomography (SPCCT) is an innovative imaging modality that could overcome the current limitations of conventional CT, offering not only better spatial resolution but also better contrast resolution by allowing the discrimination of multiple contrast agents. Based on this capability, we tested the feasibility of SPCCT in the detection of PM at different time of tumor growth in 16 rats inoculated with CC531 cells using dual-contrast injection protocols in two compartments (i.e. intravenous iodine and intraperitoneal gadolinium or the reverse protocol), compared to surgery. For all peritoneal regions and for both protocols, sensitivity was 69%, specificity was 100% and accuracy was 80%, and the correlation with surgical exploration was strong (p = 0.97; p = 0.0001). No significant difference was found in terms of diagnostic performance, quality of peritoneal opacification or diagnostic quality between the 2 injection protocols. We also showed poor vascularization of peritoneal metastases by measuring low concentrations of contrast agent in the largest lesions using SPCCT, which was confirmed by immunohistochemical analyses. In conclusion, SPCCT using dual-contrast agent injection protocols in 2 compartments is a promising imaging modality to assess the extent of PM in a rat model.

The Peritoneal Cancer Index is a Strong Predictor of Incomplete Cytoreductive Surgery in Ovarian Cancer

Background

Extent of tumor load is an important factor in the selection of ovarian cancer patients for cytoreductive surgery (CRS). The Peritoneal Cancer Index (PCI) gives exact information on tumor load but still is not standard in ovarian cancer surgery. The aim of this study was to find a PCI cutoff for incomplete CRS. The secondary aims were to identify reasons for open-close surgery and to compare surgical complications in relation to tumor burden.

Methods

The study included 167 women with stage III or IV ovarian cancer scheduled for CRS. Possible predictors of incomplete surgery were evaluated with receiver operator curves, and a PCI cutoff was identified. Surgical complications were analyzed by one-way analysis of variance and Chi square tests.

Results

The median PCI score for all the patients was 22 (range 3–37) but 33 (range 25–37) for the patients with incomplete surgery (n = 19). The PCI predicted incomplete CRS, with an area under the curve of 0.94 (95% confidence interval [CI], 0.91–0.98). Complete CRS was obtained for 67.2% of the patients with a PCI higher than 24, who experienced an increased rate of complications (p = 0.008). Overall major complications were found in 16.9% of the cases. Only 28.6% of the patients with a PCI higher than 33 achieved complete CRS. The reason for open-close surgery (n = 14) was massive carcinomatosis on the small bowel in all cases.

Conclusion

The study found PCI to be an excellent predictor of incomplete CRS. Due to a lower surgical success rate, the authors suggest that neoadjuvant chemotherapy could be considered if the PCI is higher than 24. Preoperative radiologic assessment should focus on total tumor burden and not necessarily on specific regions.

Electronic supplementary material

The online version of this article (10.1245/s10434-020-08649-6) contains supplementary material, which is available to authorized users.

Peritoneal Cancers and Hyperthermic Intraperitoneal Chemotherapy

Cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy is an aggressive, potentially curative approach used to treat locoregional disease associated with primary and secondary malignancies of the peritoneum. It involves resection of all macroscopic disease larger than 2.5 mm, followed by instillation of hyperthermic chemotherapy directly into the peritoneum for higher drug exposure to microscopic disease. In select patients with primary peritoneal mesothelioma, pseudomyxoma peritonei, colorectal adenocarcinoma, appendiceal adenocarcinoma, or ovarian cancer, with no extra-abdominal metastasis and limited involvement of the peritoneum, the procedure can be performed to increase overall survival.

Radiological assessment of Peritoneal Cancer Index on preoperative CT in ovarian cancer is related to surgical outcome and survival

PURPOSE

To evaluate whether Peritoneal Cancer Index (PCI) assessed on preoperative CT (CT-PCI) can be used as non-invasive preoperative tool to predict surgical outcome, disease-free survival (DFS) and overall survival (OS).

MATERIALS AND METHODS

This is a retrospective, observational cohort study performed in a single institution. We considered all patients with diagnosis of ovarian cancer and preoperative CT, who had undergone upfront cytoreductive surgery between 2008 and 2010 and had post-operative clinical follow-up to December 2015. Two radiologists reviewed CT scans and assessed CT-PCI using Sugarbaker's diagram. We assessed the discriminatory capacity of the CT-PCI score on the surgical outcome by ROC curve analysis. DFS and OS were assessed by Kaplan-Meier nonparametric curves and by multivariable Cox-regression analysis.

RESULTS

A total of 297 patients were included in the present analysis. CT-PCI was positively correlated with post-operative residual disease [odds ratio (OR) 1.04, 95% CI 1.01-1.07, p = 0.003]. ROC curve analysis returned AUC = 0.64 for the prediction of total macroscopic tumour clearance. In multivariable analysis, patients with no peritoneal disease seen on CT had a significantly longer DFS [Hazard ratio (HR) 2.28, p = 0.007]. Radiological serosal small bowel involvement was an independent predictor for shorter OS (HR 3.01, p = 0.002).

CONCLUSION

Radiological PCI assessed on preoperative CT is associated with the probability of residual disease after cytoreductive surgery; however, it has low performance as a triage test to reliably identify patients who are likely to have complete cytoreductive surgery. CT-PCI is positively correlated with both DFS and OS and may be used as an independent prognostic factor, for example in patients with high FIGO stages.

Extent of Peritoneal Metastases on Preoperative DW-MRI is Predictive of Disease-Free and Overall Survival for CRS/HIPEC Candidates with Colorectal Cancer

OBJECTIVE

The aim of this study was to determine whether the extent of peritoneal metastases (PMs) on preoperative diffusion-weighted magnetic resonance imaging (DW-MRI) can be used as a biomarker of disease-free and overall survival in patients with colorectal cancer who are considered for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC).

METHODS

For this retrospective cohort study, patients with PMs considered for CRS/HIPEC who underwent DW-MRI for preoperative staging in 2016-2017 were included. The DW-MRI protocol consisted of diffusion-weighted, T2-weighted, and pre- and post-gadolinium T1-weighted imaging of the chest, abdomen, and pelvis. DW-MRI images were evaluated by two independent readers to determine the extent of PMs represented by the Peritoneal Cancer Index (MRI-PCI), as well as extraperitoneal metastases. Cox regression and Kaplan-Meier analysis was performed to determine the prognostic value of DW-MRI for overall and disease-free survival.

RESULTS

Seventy-eight patients were included. CRS/HIPEC was planned for 53 patients and completed in 50 patients (60.5%). Median follow-up after DW-MRI was 23 months (interquartile range 13-24). The MRI-PCI of both readers showed prognostic value for overall survival, independently of whether R1 resection was achieved (hazard ratio [HR] 1.06-1.08; p < 0.05). For the patients who received successful CRS/HIPEC, the MRI-PCI also showed independent prognostic value for disease-free survival for both readers (HR 1.09-1.10; p < 0.05).

CONCLUSION

The extent of PMs on preoperative DW-MRI is an independent predictor of overall and disease-free survival and should therefore be considered as a non-invasive prognostic biomarker.