Combined diffusion-weighted and gadolinium-enhanced MRI can accurately predict the peritoneal cancer index preoperatively in patients being considered for cytoreductive surgical procedures

What is the optimum post treatment surveillance imaging protocol for low-grade appendiceal mucinous neoplasms and pseudomyxoma peritoneii?

Appendiceal mucinous neoplasms are rare and can be associated with the development of disseminated peritoneal disease known as pseudomyxoma peritonei (PMP). Mucinous tumours identified on appendicectomy are therefore followed up to assess for recurrence and the development of PMP. In addition, individuals who initially present with PMP and are treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) are followed up to assess for recurrence. However, despite the concerted efforts of multiple expert groups, the optimal imaging follow-up protocol is yet to be established. The purpose of this article is to review the available evidence for imaging surveillance in these populations to identify the optimum post-resection imaging follow-up protocol.

Imaging of Peritoneal Metastases in Ovarian Cancer Using MDCT, MRI, and FDG PET/CT: A Systematic Review and Meta-Analysis

This review aims to compare the diagnostic performance of multidetector CT (MDCT), MRI, including diffusion-weighted imaging, and FDG PET/CT in the detection of peritoneal metastases (PMs) in ovarian cancer (OC). A comprehensive search was performed for articles published from 2000 to February 2023. The inclusion criteria were the following: diagnosis/suspicion of PMs in patients with ovarian/fallopian/primary peritoneal cancer; initial staging or suspicion of recurrence; MDCT, MRI and/or FDG PET/CT performed for the detection of PMs; population of at least 10 patients; surgical results, histopathologic analysis, and/or radiologic follow-up, used as reference standard; and per-patient and per-region data and data for calculating sensitivity and specificity reported. In total, 33 studies were assessed, including 487 women with OC and PMs. On a per-patient basis, MRI (p = 0.03) and FDG PET/CT (p < 0.01) had higher sensitivity compared to MDCT. MRI and PET/CT had comparable sensitivities (p = 0.84). On a per-lesion analysis, no differences in sensitivity estimates were noted between MDCT and MRI (p = 0.25), MDCT and FDG PET/CT (p = 0.68), and MRI and FDG PET/CT (p = 0.35). Based on our results, FDG PET/CT and MRI are the preferred imaging modalities for the detection of PMs in OC. However, the value of FDG PET/CT and MRI compared to MDCT needs to be determined. Future research to address the limitations of the existing studies and the need for standardization and to explore the cost-effectiveness of the three imaging modalities is required.

FDG-PET/MRI for the preoperative diagnosis and staging of peritoneal carcinomatosis: a prospective multireader pilot study

PURPOSE

To assess the diagnostic performance of FDG-PET/MRI for the preoperative diagnosis and staging of peritoneal carcinomatosis (PC) using surgical Sugarbaker's PC index (PCI) as the reference in a multireader pilot study.

METHODS

Fourteen adult patients (M/F: 3/11, mean age: 57 ± 12 year) with PC were prospectively included in this single-center study. Patients underwent FDG-PET/MRI prior to surgery (mean delay: 14 d, range: 1-63 d). Images were reviewed independently by 2 abdominal radiologists and 2 nuclear medicine physicians. The radiologists assessed contrast-enhanced abdominal MR images, while the nuclear medicine physicians assessed PET images fused with T2-weighted images. The abdomen was divided in 13 regions, scored from 0 to 3. A hybrid FDG-PET/MRI radiological PCI was created by combining the study data. Radiological PCI was compared to the surgical PCI on a per-patient and per-region basis. Inter-reader agreement was evaluated.

RESULTS

Mean surgical PCI was 10 ± 8 (range: 0-24). Inter-reader agreement was almost perfect for all sets for radiologic PCI (Kappa: 0.81-0.98). PCI scores for all reading sets significantly correlated with the surgical PCI score (r range: 0.57-0.74, p range: < 0.001-0.003). Pooled per-patient sensitivity, specificity, and accuracy were 75%/50%/71.4% for MRI, 66.7%/50%/64.3% for FDG-PET, and 91.7%/50%/85.7% for FDG-PET/MRI, without significant difference (p value range 0.13-1). FDG-PET/MRI achieved 100% sensitivity and 100% specificity for a cutoff PCI of 20. Per-region sensitivity and accuracy were lower: 37%/61.8% for MRI, 17.8%/64.3% for FDG-PET, and 52.7%/60.4% for FDG-PET/MRI, with significantly higher sensitivity for FDG-PET/MRI. Per-region specificity was higher for FDG-PET (95%) compared to MRI (78.4%) and FDG-PET/MRI (66.5%).

CONCLUSION

FDG-PET/MRI achieved an excellent diagnostic accuracy per-patient and weaker performance per-region for detection of PC. The added value of PET/MRI compared to MRI and FDG-PET remains to be determined.

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.

Imaging of Malignant Pleural, Pericardial, and Peritoneal Mesothelioma

Malignant mesothelioma is a rare tumor arising from the mesothelial cells that line the pleura, pericardium, peritoneum, and tunica vaginalis. Imaging plays a primary role in the diagnosis, staging, and management of malignant mesothelioma. Multimodality imaging, including radiography, computed tomography (CT), magnetic resonance imaging (MRI), and F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT), is used in a variety of scenarios, including diagnosis, guidance for tissue sampling, staging, and reassessment of disease after therapy. CT is the primary imaging modality used in staging. MRI has superior contrast resolution compared with CT and can add value in terms of determining surgical resectability in equivocal cases. MRI can further assess the degree of local invasion, particularly into the mediastinum, chest wall, and diaphragm, for malignant pleural and pericardial mesotheliomas. FDG PET/CT plays a role in the diagnosis and staging of malignant pleural mesothelioma (MPM) and has been shown to be more accurate than CT, MRI, and PET alone in the staging of malignant pleural mesothelioma. PET/CT can also be used to target lesions for biopsy and to assess prognosis, treatment response, and tumor recurrence.

Surgical case report: The rare case of incidental retroperitoneal mesothelioma

INTRODUCTION AND IMPORTANCE

This is a first reported case of isolated retroperitoneal mesothelioma. Most patients present with symptoms of abdominal pain, distension and weight loss. However, a minority of cases are asymptomatic and are found incidentally on imaging. It is important to provide an early histological diagnosis to help with management and prognostication.

CASE PRESENTATION

We present a male patient who was referred to our surgical clinic with an incidental finding of an indeterminate retroperitoneal lesion. The patient underwent numerous investigations without further clarity of the lesion. A 5 cm lobulated cystic lesion was excised in the retroperitoneum and found to be loosely adherent but separate to the duodenum, inferior vena cava and right adrenal gland. Histopathology revealed a localised multinodular epithelioid mesothelioma. The patient was referred to a specialist cancer centre and has remained well on subsequent follow-up.

CLINICAL DISCUSSION

Although multiple reports of lung, liver and kidney mesotheliomas are described, to our knowledge this is the first report of isolated retroperitoneal mesothelioma. Diagnosis of peritoneal mesothelioma is diagnostically challenging as there are no features on imaging characteristic for peritoneal mesothelioma. Hence, tumour markers and magnetic resonance imaging should be used in conjunction. The prognosis of mesothelioma is dependent on the patients' histopathology, where diffuse mesothelioma poses a worse prognosis than localised mesothelioma. Modern therapies for diffuse mesothelioma now include cytoreduction surgery (CRS) and hyperthermic intraoperative peritoneal perfusion with chemotherapy (HIPEC).

CONCLUSION

An excisional biopsy may be warranted for indeterminate lesions with a high degree of suspicion for malignancy.

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.

Impact of myometrium invasion on survival outcomes following cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC)

INTRODUCTION

Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is an effective surgical intervention for peritoneal surface malignancy. The effect of myometrium invasion on outcomes is unknown.

METHODS

Retrospective review of our institutional registry with analysis of CRS-HIPEC cases involving a hysterectomy. Compared cases with myometrium invasion versus those without invasion. Primary outcome was survival as measured by overall survival (OS) and disease-free survival (DFS). Secondary outcome was the evaluation of risk factors for myometrium invasion based on multivariate analysis.

RESULTS

A total of 126 cases of CRS-HIPEC involving a hysterectomy were identified. Ninety-seven cases (76.9%) had no myometrium invasion and the remaining 29 cases (23.1%) had malignant invasion. The presence of myometrial invasion was a significant negative survival prognostic factor. The OS was halved with mean survival times of 2.8 (±2.3) versus 5.8 (±4.7) years for cases with and without invasion, respectively (p = 0.002). Five-year OS rates were also inferior with myometrium invasion at 17.4% versus 53.8% (odds ratio [OR] = 0.181, 95% confidence interval [CI]: 0.057-0.580, p = 0.002). A similar trend was present with DFS with mean survival times of 1.4 (±0.9) versus 3.7 (±3.9) years for noninvasion and invasion cases (p = 0.009). The 5-year DFS rates were 0% versus 34.8% (OR = 0.652, 95% CI: 0.549-0.775, p = 0.004). Secondary analysis significantly associated several risk factors with myometrium invasion to include lymph node positivity (OR = 2.539, 95% CI: 1.074-6.003, p = 0.012), colorectal primary tumors (OR = 2.248, 95% CI: 1.094-5.161, p = 0.035), and high-grade tumors (OR = 2.160, 95% CI: 1.080-4.820, p = 0.038).

CONCLUSION

Myometrium invasion is a significant negative prognostic factor for survival following CRS-HIPEC. Several risk factors are potentially predictive of identifying those at high-risk for myometrium invasion.

Imaging Recommendations for Diagnosis, Staging, and Management of Ovarian and Fallopian Tube Cancers

Ovarian malignancy the third most common gynecological malignancy and is the leading cause of death in women. Non-specific clinical presentation delays the diagnosis, and they often present in the advanced stage of disease. No imaging modality is recommended for screening as there is no significant mortality reduction. Ultrasound (USG) is usually the initial modality in suspected ovarian mass. MRI is recommended for the characterization of indeterminate ovarian or adnexal mass on USG. CT abdomen and pelvis with oral and IV contrast is the recommended imaging modality in staging the disease, predicting the resectability and in selecting the patients who would benefit from neoadjuvant chemotherapy. Early ovarian cancers are staged by post-surgical histology and undergo upfront surgery. Advanced disease benefit by neoadjuvant chemotherapy and less morbidity by interval cytoreduction where image-guided biopsy is performed for histological diagnosis. Follow-up recommendations are based on tumor histology. CT/PET CT is recommended for diagnosing recurrence.

Malignant peritoneal mesothelioma

Malignant peritoneal mesothelioma (MPM) is a rare, life-threatening malignant tumor. We present a report of a rare case of a 67-year-old male patient with MPM and severe abdominal pain, bloating, and bloody ascites as manifestations. The diagnosis was confirmed by cytology of ascites aspiration fluid and further verified by laparoscopic exploratory biopsy. The characteristics of signs and clinical manifestations in this case are less common. As everyone knows, asbestos exposure is usually associated with pleural mesothelioma, but only 6%-10% of malignant mesothelioma cases originate from the peritoneum, which is far less than pleural mesothelioma. Generally, its non-specificity provides a huge challenge to medical professionals in its diagnosis, and this is also the main reason for delayed diagnosis. Patients should be vigilant, even though no clear risk factor is observed.

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.

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.

Differences in the distribution of peritoneal metastases in right- versus left-sided colon cancer on MRI

PURPOSE

Right-sided colon tumors with peritoneal metastases (PM) are associated with a poorer prognosis than left-sided tumors. We hypothesized that a different pattern of spread could be characterized with abdominopelvic MRI. The objective of this study was to explore the spread of PM in relation to the primary tumor location on MRI.

METHODS

This is a retrospective cohort study of patients with PM from colon cancer referred to be considered for CRS-HIPEC at a single tertiary referral center. Patients with colon cancer were eligible if they had undergone an abdominopelvic MRI scan following a clinical diagnosis of PM. The frequency of affected PCI regions on MRI (MRI-PCI) was assessed and compared between tumor sidedness.

RESULTS

One hundred eighteen patients were included with a median age of 65 (IQR: 56-72). 46% percent were male. The median MRI-PCI was 10 (IQR: 5-16) and 8 (IQR: 4-11) for right- and left-sided tumors, respectively (p = 0.39), and the median number of affected regions was 4 (IQR: 2-7 for right-sided and IQR 2-5 for left-sided tumors). PM was most frequently found close to the primary tumor. The odds ratio of patients with PM of left sided to be affected with PM in the upper abdominal regions was 0.42 (95% CI: 0.20-0.90) and with PM on the small bowels or mesentery was 0.42 (95% CI: 0.19-0.92) over a patient with PM of right-sided colon cancer.

CONCLUSION

MRI can help to assess the spread of PM in colonic cancer. In right-sided tumors, the small bowel and upper abdominal regions are more frequently affected.

Appendiceal tumors and pseudomyxoma peritonei: French Intergroup Clinical Practice Guidelines for diagnosis, treatments and follow-up (RENAPE, RENAPATH, SNFGE, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO, ACHBT, SFR)

INTRODUCTION

This document is a summary of the French Intergroup guidelines regarding the management of appendicular epithelial tumors (AT) and pseudomyxoma peritonei (PMP) published in March 2020, available on the website of the French Society of Gastroenterology (SNFGE) (www.tncd.org).

METHODS

All French medical societies specialized in the management of AT and PMP collaboratively established these recommendations based on literature until December 2019 and the results of a Delphi vote carried out by the Peritoneal Surface Oncology Group International experts, and graded into 4 categories (A, B, C, Expert Agreement) according to their level of evidence.

RESULTS

AT and PMP are rare but represent a wide range of clinico-pathological entities with several pathological classification systems and different biological behaviors. Their treatment modalities may vary accordingly and range from simple surveillance or laparoscopic appendectomy to complete cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) and / or systemic chemotherapy. The prognosis of these neoplasms may also largely vary according to their pathological grade and spreading at diagnosis or during the follow-up. Given the rarity of certain situations, the therapeutic strategy adapted to each patient, must be discussed in a specialized multidisciplinary meeting after a specialized pathological and radiological pre-therapeutic assessment and a clinical examination by a surgeon specializing in the management of rare peritoneal malignancies.

CONCLUSION

These recommendations are proposed to achieve the most beneficial strategy in a daily practice as the wide range and the rareness of these entities renders their management challenging. These guidelines are permanently being reviewed.

Primary and metastatic peritoneal surface malignancies

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

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.

Concerning CT features predict outcome of treatment in patients with malignant peritoneal mesothelioma

BACKGROUND

Malignant peritoneal mesothelioma is an aggressive local-regional disease with dissemination to all parts of the abdomen and pelvis at the time of diagnosis. Recently, cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) has been used and improved survival was documented with this local-regional treatment strategy.

METHOD

Concerning CT features were described that were specific for malignant peritoneal mesothelioma. The incidence of concerning radiologic features and their impact on survival was determined. The prognostic assessment of concerning CT features was compared to the peritoneal cancer index (PCI) and the completeness of cytoreduction score (CC score).

RESULTS

One hundred patients with a preoperative CT were evaluated by 11 concerning CT features. The incidence of these CT features varied between 5% and 41%. Nine of the 11 CT features statistically significantly predicted a reduced survival in these patients treated in a uniform manner. When concerning radiologic features were grouped as none, a single feature or two or more features, a significant composite analysis was achieved with p < 0.001. The prognostic information from concerning CT features compared favorably with the prognostic implications of PCI and CC score.

CONCLUSIONS

The availability of the concerning CT features to predict prognosis at the initiation of treatments for malignant peritoneal mesothelioma shows that this radiologic assessment may be of great value to the clinician in planning a treatment strategy for an individual patient.

Diagnostic value of diffusion-weighted imaging/magnetic resonance imaging for peritoneal metastasis from malignant tumor: A systematic review and meta-analysis

BACKGROUND

Previous meta-analyses examined either multiple tools for the diagnosis of peritoneal metastases (PMs), but not diffusion-weighted imaging (DWI), or included only 1 tumor type. This study aimed to determine the summary diagnostic value of DWI/magnetic resonance imaging in determining PMs originating from various tumors.

METHODS

PubMed, Embase, and Cochrane library were searched for available papers up to 2019/12. Pooled estimates for sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and accuracy were calculated using random-effects models.

RESULTS

Ten studies were included and could be used to calculate the pooled sensitivity and specificity. The pooled sensitivity of DWI for PMs was 89% (95% confidence interval [CI]: 83%-93%). The pooled specificity was 86% (95% CI: 79%-91%). When considering only the retrospective studies, the pooled sensitivity of DWI for PMs was 85% (95% CI: 81%-89%). The pooled specificity was 84% (95% CI: 72%-92%). When considering only the studies about gastrointestinal tumors, the pooled sensitivity of DWI for PMs was 97% (95% CI: 68%-100%). The pooled specificity was 86% (95% CI: 69%-95%). No publication bias was observed (P = dd.27).

CONCLUSION

DWI magnetic resonance imaging is highly sensitive and specific for the detection of PMs from various abdominal cancers.

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.

MR Imaging of the Perihepatic Space

The perihepatic space is frequently involved in a spectrum of diseases, including intrahepatic lesions extending to the liver capsule and disease conditions involving adjacent organs extending to the perihepatic space or spreading thanks to the communication from intraperitoneal or extraperitoneal sites through the hepatic ligaments. Lesions resulting from the dissemination of peritoneal processes may also affect the perihepatic space. Here we discuss how to assess the perihepatic origin of a lesion and describe the magnetic resonance imaging (MRI) features of normal structures and fluids that may be abnormally located in the perihepatic space. We then review and illustrate the MRI findings present in cases of perihepatic infectious, tumor-related, and miscellaneous conditions. Finally, we highlight the value of MRI over computed tomography.

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.

Imaging before cytoreductive surgery in advanced ovarian cancer patients

Appropriate and accurate pre-operative imaging in epithelial ovarian cancer patients may allow selection of patients that may mostly benefit either from primary cytoreductive surgery or from neoadjuvant chemotherapy. If the patient is considered suitable for upfront surgery, pre-operative imaging may help in planning the surgical approach, to forecast the operating time, and to estimate the need for other consulting specialists. Currently, computed tomography (CT) imaging is the standard of care for pre-operative evaluation of ovarian cancer patients; however, advanced magnetic resonance imaging (MRI) is emerging as a technique that may overcome the limitations of CT imaging, especially for small peritoneal deposits in difficult-to-resect sites. Positron emission tomography (PET)-CT imaging in the pre-operative setting is currently limited, whereas the use of the new hybrid technique PET-MRI is still under evaluation. Since criteria that may preclude optimal cytoreductive surgery may vary, depending on the aggressiveness of the surgical procedure and surgeon skill, multidisciplinary consensus conferences are the ideal platform to evaluate extent of the disease and surgical strategy.

Diagnostic Laparoscopy as a Selection Tool for Patients with Colorectal Peritoneal Metastases to Prevent a Non-therapeutic Laparotomy During Cytoreductive Surgery

OBJECTIVE

The aim of this study was to evaluate the introduction of diagnostic laparoscopy (DLS) in patients with colorectal peritoneal metastases (PM) to prevent non-therapeutic laparotomies during cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS + HIPEC).

METHODS

Patients with histologically proven colorectal PM who underwent a laparotomy for potential CRS + HIPEC from January 2006 to January 2019 were retrospectively identified from a prospectively maintained database. In 2012, DLS was introduced in the preoperative work-up for CRS + HIPEC in our academic center. The rates of non-therapeutic laparotomies, major postoperative complications (Clavien-Dindo grade III or higher), and survival outcomes were investigated for patients who underwent a laparotomy before (cohort A) and after (cohort B) the introduction of DLS. In cohort B, the reasons to refrain from DLS were retrospectively explored from medical records.

RESULTS

Overall, 172 patients were included [cohort A: 48 patients (27.9%); cohort B: 124 patients (72.1%)]. A significant drop in the rate of non-therapeutic laparotomies occurred in cohort B compared with cohort A (21.0 vs. 35.4%: p = 0.044), despite only 85 patients (68.5%) from cohort B undergoing DLS in our academic center. The most important reason to refrain from DLS was a recently performed DLS or laparotomy in the referring hospital (48.7%). Major postoperative complications, in-hospital mortality, and survival outcomes were similar for both cohorts.

CONCLUSIONS

Performing DLS during the preoperative work-up for CRS + HIPEC prevents non-therapeutic laparotomies in patients with colorectal PM. We recommend performing this laparoscopic screening in an experienced HIPEC center.

Diffusion-weighted magnetic resonance imaging in peritoneal carcinomatosis from suspected ovarian cancer: Diagnostic performance in correlation with surgical findings

PURPOSE

Ovarian cancer (OC) is the commonest cause of death by gynaecological cancer in developed countries. Peritoneal carcinomatosis (PC) complete debulking without residual disease of >1 cm is the best prognostic predictor in advanced OC. PC is assessed with Computed tomography (CT). CT accuracy and cytoreduction success predictive ability are limited. PET/CT is not an imaging standard for PC. PC shows high signal foci in Diffusion-weighted magnetic resonance imaging (DWI MRI). We assessed the diagnostic performance (DP) and tumour burden correlation of Whole body DWI with background suppression MRI (WB-DWIBS/MRI) in PC of suspected OC using the Peritoneal Cancer Index (PCI), referring to cytoreduction surgery as the standard reference.

METHOD

Fifty patients with suspicion of disseminated OC underwent cytoreduction and WB-DWIBS/MRI. The PCI scores tumour burden (0-3) in 13 anatomical regions (global range of 0-39). Two radiologists (Rad1/Rad2) assessed the PCI preoperatively and with surgical findings. We evaluated regional and global DP, the interobserver agreement (Cohen´s kappa coefficient), statistical differences (McNemar test) and tumour burden (Pearson's test).

RESULTS

72% (36/50) were epithelial OC and 78% (39/50) achieved complete cytoreduction. Global-PCI correlation was 0.762 (Rad1) with DP: Sensitivity 0.84, specificity 0.89, accuracy 0.89, and kappa 0.41. Average global-PCI was 7. The pelvis and right hypochondrium showed the highest positive rate and DP, while the intestinal regions presented the lowest. Previous studies reported higher sensitivity than CT or PET/CT, although only a few used the PCI.

CONCLUSIONS

WB-DWIBS/MRI is reliable to depict, quantify and to predict complete cytoreductive surgery in OC PC.

Mesothelioma: Scientific clues for prevention, diagnosis, and therapy

Mesothelioma affects mostly older individuals who have been occupationally exposed to asbestos. The global mesothelioma incidence and mortality rates are unknown, because data are not available from developing countries that continue to use large amounts of asbestos. The incidence rate of mesothelioma has decreased in Australia, the United States, and Western Europe, where the use of asbestos was banned or strictly regulated in the 1970s and 1980s, demonstrating the value of these preventive measures. However, in these same countries, the overall number of deaths from mesothelioma has not decreased as the size of the population and the percentage of old people have increased. Moreover, hotspots of mesothelioma may occur when carcinogenic fibers that are present in the environment are disturbed as rural areas are being developed. Novel immunohistochemical and molecular markers have improved the accuracy of diagnosis; however, about 14% (high-resource countries) to 50% (developing countries) of mesothelioma diagnoses are incorrect, resulting in inadequate treatment and complicating epidemiological studies. The discovery that germline BRCA1-asssociated protein 1 (BAP1) mutations cause mesothelioma and other cancers (BAP1 cancer syndrome) elucidated some of the key pathogenic mechanisms, and treatments targeting these molecular mechanisms and/or modulating the immune response are being tested. The role of surgery in pleural mesothelioma is controversial as it is difficult to predict who will benefit from aggressive management, even when local therapies are added to existing or novel systemic treatments. Treatment outcomes are improving, however, for peritoneal mesothelioma. Multidisciplinary international collaboration will be necessary to improve prevention, early detection, and treatment.

FOLFIRINOX in patients with peritoneal carcinomatosis from pancreatic adenocarcinoma: a retrospective study

Background

Peritoneal carcinomatosis (pcm) in metastatic pancreatic ductal adenocarcinomas (mpdac) is frequently encountered in day-to-day practice, but rarely addressed in the literature. The objective of the present study was to describe the management and outcome of patients diagnosed with pcm.

Methods

Data for all consecutive patients with mpdac treated in our centre between 1 January 2014 and 31 August 2015 were analyzed retrospectively. Computed tomography imaging was centrally reviewed by a dedicated radiologist to determine the date of pcm diagnosis.

Results

The analysis included 48 patients. Median age in the group was 61 years, and 41 patients had an Eastern Cooperative Oncology Group performance status (ecog ps) of 0-1. All patients presented with pcm either synchronously (group 1) or metachronously (group 2). Those groups differed significantly by baseline ecog ps and neutrophil-to-lymphocyte ratio (nlr), with ecog ps being poorer and nlr being higher in group 1. In addition to pcm, the main sites of metastasis were liver (62.5%) and lungs (31.3%). First-line chemotherapy in 36 patients (75%) was folfirinox (fluorouracil-irinotecan-leucovorin-oxaliplatin). The median overall survival for the entire population was 10.81 months [95% confidence interval (ci): 7.16 months to 14.16 months]; it was 13.17 months (95% ci: 5.9 months to 15.4 months) for patients treated with folfirinox. Median overall survival was 7.13 months (95% ci: 4.24 months to 10.41 months) for patients in group 1 and 14.34 months (95% ci: 9.79 months to 19.91 months) for patients in group 2, p = 0.1296.

Conclusions

Compared with other metastatic sites, synchronous pcm seems to be a poor prognostic factor. It could be more frequently associated with a poor ecog ps and a nlr greater than 5 in this group of patients. In patients with mpdac and pcm, either synchronous or metachronous, folfirinox remains an efficient regimen.

Improved Peritoneal Cavity and Abdominal Organ Imaging Using a Biphasic Contrast Agent Protocol and Spectral Photon Counting Computed Tomography K-Edge Imaging

OBJECTIVES

To validate in vitro the capability of a high-spatial-resolution prototype spectral photon-counting computed tomography (SPCCT) scanner to differentiate between 2 contrast agents and to assess in vivo the image quality and the feasibility to image the peritoneal cavity in rats using the 2 contrast agents simultaneously within the vascular and peritoneal compartments.

MATERIALS AND METHODS

The authors performed SPCCT imaging (100 mAs, 120 kVp) with energy bin thresholds set to 30, 51, 64, 72, and 85 keV in vitro on a custom-made polyoxymethylene cylindrical phantom consisting of tubes with dilutions of both contrast agents and in vivo on 2 groups of adult rats using 2 injection protocols. Approval from the institutional animal ethics committee was obtained. One group received macrocylic gadolinium chelate intraperitoneal (IP) and iodine intravenous (IV) injections (protocol A, n = 3), whereas the second group received iodine IP and gadolinium IV (protocol B, n = 3). Helical scans were performed 35 minutes after IP injection and 20 seconds after IV injection. The SPCCT and contrast material images, that is, iodine and gadolinium maps, were reconstructed with a field of view of 160 mm, an isotropic voxel size of 250 μm, and a matrix size of 640 × 640 pixels using a soft reconstruction kernel. The SPCCT images were reconstructed with 2 different spatial resolutions to compare the image quality (sharpness, diagnostic quality, and organ visualization) of SPCCT (250 μm) with single-energy computed tomography (CT) (600 μm). Two radiologists evaluated the peritoneal opacification index in 13 regions (score = 0-3 per region) on each type of image. Concentrations of contrast agents were measured in the organs of interest.

RESULTS

In vitro, the concentration measurements correlated well with the expected concentrations. The linear regressions both had R values of 0.99, slopes of 0.84 and 0.87, and offsets at -0.52 and -0.38 mg/mL for iodine and gadolinium, respectively. In vivo, the SPCCT images were of better diagnostic quality, with increased sharpness compared with the CT-like images (P < 0.0001). Intraperitoneal diffusion was excellent, with similar peritoneal opacification index on SPCCT images and overlay of contrast material maps (P = 1) without a significant difference between protocol A (37.0 ± 1.7) and protocol B (35.3 ± 1.5) (P = 0.34). Only the contrast material maps demonstrated clear visual separation of the contrast agents, allowing specific quantification of the physiological enhancement in the liver, spleen, and kidney and the urinary clearance in the renal pelvis and bladder. Renal excretion of the contrast agents injected IP was observed and was consistent with blood diffusion.

CONCLUSIONS

Spectral photon-counting CT can be used to perform a complete peritoneal dual-contrast protocol, enabling a good assessment of the peritoneal cavity and abdominal organs in rats.

Extended abdominopelvic MRI versus CT at the time of adnexal mass characterization for assessing radiologic peritoneal cancer index (PCI) prior to cytoreductive surgery

PURPOSE

To evaluate whether extending the MRI scan to include the abdomen at the time of adnexal mass characterization could replace additional CT for peritoneal cancer index (PCI) assessment.

METHODS

After institutional review board approval for this prospective study, 36 consecutive females with ovarian and FT malignancies were included. All patients signed an informed consent. Patients underwent preoperative CT (32 patients) and MRI (36 patients). Images were interpreted by 2 independent observers. Surgical data were available in 27 patients. Region-by-region analysis was performed for detection rates of peritoneal carcinomatosis (PC). Inter-observer agreement for each region was evaluated by kappa statistics. Radiologic PCI was calculated by CT and MRI independently and inter-observer agreement for CT and MRI as well as agreement between radiologic and surgical PCI were evaluated by weighted-kappa statistics.

RESULTS

On region-by-region analysis, the highest detection rates of PC were noted at the central abdomen and pelvis. Detection rates were higher by MRI than CT, mainly in bowel serosal surface, pelvis, and right upper abdomen regions. Inter-observer agreement of MRI was higher than CT in most regions. The median PCI by CT was 5 and 4 for the first and second observers (range 0-21 for both observers), respectively. The median PCI by MRI was 6 (range 0-23 for both observers). The inter-observer agreement of PCI was excellent by both CT and MRI (k = 0.876 and k = 0.912, respectively). The agreement between CT and surgical PCI was 0.660 and 0.590 for the first and second observers, respectively. The agreement between MRI and surgical PCI was 0.797 and 0.798 for the first and second observers, respectively.

CONCLUSIONS

Extending MRI scan to include the abdomen at the time of adnexal mass characterization allows accurate estimation of PC, with better results than CT, obviating the need for dedicated CT scan of abdomen and pelvis for imaging of PC.

Malignant Peritoneal Mesothelioma Without Asbestos Exposure

Malignant mesothelioma is a rare neoplasm of the serosal linings. Mesothelioma has been linked to asbestos exposure, with prior asbestos exposure linked to 33-50% of malignant peritoneal mesotheliomas. We describe a case of malignant peritoneal mesothelioma (MPM) without any prior exposure to asbestos in a 40-year-old Hispanic female who presented to the emergency department with worsening abdominal pain and distension. She had a history of beta thalassemia trait and iron deficiency anemia. Examination revealed a distended abdomen with protruding umbilicus and positive shifting dullness. Laboratory tests showed anemia. Computed tomography (CT) of the abdomen revealed massive complex ascites suspicious of a malignant process. Ascitic fluid analysis showed serum ascites albumin gradient (SAAG) of 1.1 g/dL with a total protein of 5.2 g/dL. She underwent laparoscopic peritoneal biopsy which yielded epithelioid type malignant mesothelioma. She was started on chemotherapy with cisplatin and pemetrexed. The last follow-up was 27 months after the diagnosis. MPM is a rare and life-threatening malignancy. Frequently, the symptoms are non-specific. This poses a diagnostic challenge for physicians and probably the reason why the diagnosis is often delayed, especially in the absence of risk factors.

ACR Appropriateness Criteria® Staging and Follow-Up of Ovarian Cancer

In the management of epithelial ovarian cancers, imaging is used for cancer detection and staging, both before and after initial treatment. The decision of whether to pursue initial cytoreductive surgery for ovarian cancer depends in part on accurate staging. Contrast-enhanced CT of the abdomen and pelvis (and chest where indicated) is the current imaging modality of choice for the initial staging evaluation of ovarian cancer. Fluorine-18-2-fluoro-2-deoxy-d-glucose PET/CT and MRI may be appropriate for problem-solving purposes, particularly when lesions are present on CT but considered indeterminate. In patients who achieve remission, clinical suspicion for relapse after treatment prompts imaging evaluation for recurrence. Contrast-enhanced CT is the modality of choice to assess the extent of recurrent disease, and fluorine-18-2-fluoro-2-deoxy-d-glucose PET/CT is also usually appropriate, as small metastatic foci may be identified. If imaging or clinical examination confirms a recurrence, the extent of disease and timing of disease recurrence then determines the choice of treatments, including surgery, chemotherapy, and radiation therapy. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Peritoneal MRI in patients undergoing cytoreductive surgery and HIPEC: History, clinical applications, and implementation

MR imaging provides considerable advantages in the evaluation of patients with peritoneal metastases. A standardized peritoneal MRI protocol, including diffusion-weighted and gadolinium-enhanced sequences, allows an efficient exploration of small peritoneal tumors that are often missed on other imaging tests. In experienced hands, a dedicated reading allows producing a quantitative and qualitative evaluation of lesional localization to better assist surgeons in the selection of candidates for curative surgery by evaluating the possibility of complete resection, and to plan the surgical procedure. Based on a close collaboration between oncologic surgeon and radiologist, MRI provides a powerful tool for accurate preoperative imaging in patients being considered for curative surgery but also in their surveillance to detect an early recurrence.

Imaging in the pre-operative staging of ovarian cancer

The main prognostic factor in ovarian cancer is the stage of disease at diagnosis. The staging system in use (FIGO classification, updated in 2014) is based on the surgical-pathological findings. Although surgical staging is the gold standard in ovarian cancer, the initial patient management depends on the imaging-based pre-surgical staging assessment, in order to identify unresectable or difficult to resect disease. Radiologists need to be aware of the strengths of the available imaging modalities, as well as the imaging pitfalls. Clear understanding of pattern of disease spread and review areas are critical for accurate staging and treatment planning. The current standard of care for pre-surgical staging is CT of the thorax, abdomen, and pelvis. This allows a rapid evaluation of disease extent and is fairly accurate in identifying bulky disease but has definite limitations in assessing the extent of small volume disease and in the confirmation of certain sites of disease beyond the abdomen. Functional MRI has been reported to be superior in detecting small peritoneal deposits. PET/CT may be used as a problem-solving tool in some patients where determination remains unclear, particularly in confirmation of advanced stage beyond the abdomen.

Whole-body diffusion-weighted MRI for operability assessment in patients with colorectal cancer and peritoneal metastases

Background

Correct staging of patients with colorectal cancer is of utmost importance for the prediction of operability. Although computed tomography (CT) has a good overall performance, estimation of peritoneal cancer spread is a known weakness, a problem that cannot always be overcome by Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT); especially in infiltrative and miliary disease spread. Due to its high spatial and contrast resolution magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) might have a better performance. Our aim was to evaluate the added value of whole-body diffusion-weighted MRI (WB-DWI/MRI) to CT for prediction of peritoneal cancer spread and operability assessment in colorectal cancer patients with clinically suspected peritoneal carcinomatosis (PC).

Methods

This institutional review board approved retrospective study included sixty colorectal cancer patients who underwent WB-DWI/MRI in addition to CT for clinically suspected peritoneal metastases. WB-DWI/MRI and CT were assessed for detecting PC following the peritoneal cancer index (PCI), determination of PCI-score categorized as PC < 12, PCI = 12–15 and PCI > 15, detection of nodal and distant metastases and estimation of overall operability. Histopathology after surgery and biopsy and/or 6 months follow-up were used as reference standard.

Results

For detection of PC, CT had 43.2% sensitivity, 95.6% specificity, 84.5% positive predictive value (PPV) and 75.2% negative predictive value (NPV). WB-DWI/MRI had 97.8% sensitivity, 93.2% specificity, 88.9% PPV and 98.7% NPV. WB-DWI/MRI enabled better detection of inoperable distant metastases (all 12 patients) than CT (2/12 patients) and significantly improved prediction of PCI category [WB-DWI/MRI PCI < 12: 37/39 patients (94.9%); PCI = 12–15: 4/4 patients (100%); PCI > 15: 16/17 patients (94.1%) versus CT PCI < 12: 38/39 patients (97.4%); PCI = 12–15: 0/4 patients (0%); PCI > 15: 2/17 patients (11.8%); p < 0.0001)]. WB-DWI/MRI improved prediction of inoperability over CT with 90.6% sensitivity compared to 25% (p < 0.0001).

Conclusions

WB-DWI/MRI significantly outperformed CT for estimation of spread of PC, overall staging and prediction of operability. Pending validation in larger prospective trials, WB-DWI/MRI could be used to guide surgical planning and minimize unnecessary exploratory laparotomies.

Optimization of surgical treatment of advanced ovarian cancer: a Spanish expert perspective

BACKGROUND

Optimal upfront treatment of patients with advanced ovarian cancer is complex and requires the adequate function of a multidisciplinary team. Specific standard of quality of care needs to be taken into consideration.

METHODS

A literature search in PubMed was performed using the following criteria: ("ovarian neoplasms"[MeSH Terms] OR ("ovarian"[All Fields] AND "neoplasms"[All Fields]) OR "ovarian neoplasms"[All Fields] OR ("ovarian"[All Fields] AND "cancer"[All Fields]) OR "ovarian cancer"[All Fields])"[Date - Publication]: "2018/01/14"[Date - Publication]).

RESULTS

This article describes how to optimize the surgical management of advanced ovarian cancer, to achieve the best results in terms of survival and quality of life. For this purpose, this document will cover aspects related to pre-, intra- and postoperative care of newly diagnosed advanced ovarian cancer patients.

CONCLUSION

Optimizing upfront treatment of patients with advanced ovarian cancer is complex and requires a structured quality management program including the wise judgment of a multidisciplinary team. Surgeries performed by gynecologic oncologists with formal training in cytoreductive techniques at referral centers are crucial factors to obtain better clinical and oncological outcomes. However, other factors such as the patient's clinical status, the hospital infrastructure and equipment, as well as the tumor biology of each individual patient should also be taken into account before deciding on an initial therapeutic strategy for advanced-stage ovarian cancer to offer patients the best quality of care.

Positron emission tomography (PET) and magnetic resonance imaging (MRI) for assessing tumour resectability in advanced epithelial ovarian/fallopian tube/primary peritoneal cancer

BACKGROUND

Ovarian cancer is the leading cause of death from gynaecological cancer in developed countries. Surgery and chemotherapy are considered its mainstay of treatment and the completeness of surgery is a major prognostic factor for survival in these women. Currently, computed tomography (CT) is used to preoperatively assess tumour resectability. If considered feasible, women will be scheduled for primary debulking surgery (i.e. surgical efforts to remove the bulk of tumour with the aim of leaving no visible (macroscopic) tumour). If primary debulking is not considered feasible (i.e. the tumour load is too extensive), women will receive neoadjuvant chemotherapy to reduce tumour load and subsequently undergo (interval) surgery. However, CT is imperfect in assessing tumour resectability, so additional imaging modalities can be considered to optimise treatment selection.

OBJECTIVES

To assess the diagnostic accuracy of fluorodeoxyglucose-18 (FDG) PET/CT, conventional and diffusion-weighted (DW) MRI as replacement or add-on to abdominal CT, for assessing tumour resectability at primary debulking surgery in women with stage III to IV epithelial ovarian/fallopian tube/primary peritoneal cancer.

SEARCH METHODS

We searched MEDLINE and Embase (OVID) for potential eligible studies (1946 to 23 February 2017). Additionally, ClinicalTrials.gov, WHO-ICTRP and the reference list of all relevant studies were searched.

SELECTION CRITERIA

Diagnostic accuracy studies addressing the accuracy of preoperative FDG-PET/CT, conventional or DW-MRI on assessing tumour resectability in women with advanced stage (III to IV) epithelial ovarian/fallopian tube/primary peritoneal cancer who are scheduled to undergo primary debulking surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently screened titles and abstracts for relevance and inclusion, extracted data and performed methodological quality assessment using QUADAS-2. The limited number of studies did not permit meta-analyses.

MAIN RESULTS

Five studies (544 participants) were included in the analysis. All studies performed the index test as replacement of abdominal CT. Two studies (366 participants) addressed the accuracy of FDG-PET/CT for assessing incomplete debulking with residual disease of any size (> 0 cm) with sensitivities of 1.0 (95% CI 0.54 to 1.0) and 0.66 (95% CI 0.60 to 0.73) and specificities of 1.0 (95% CI 0.80 to 1.0) and 0.88 (95% CI 0.80 to 0.93), respectively (low- and moderate-certainty evidence). Three studies (178 participants) investigated MRI for different target conditions, of which two investigated DW-MRI and one conventional MRI. The first study showed that DW-MRI determines incomplete debulking with residual disease of any size with a sensitivity of 0.94 (95% CI 0.83 to 0.99) and a specificity of 0.98 (95% CI 0.88 to 1.00) (low- and moderate-certainty evidence). For abdominal CT, the sensitivity for assessing incomplete debulking was 0.66 (95% CI 0.52 to 0.78) and the specificity 0.77 (95% CI 0.63 to 0.87) (low- and low-certainty evidence). The second study reported a sensitivity of DW-MRI of 0.75 (95% CI 0.35 to 0.97) and a specificity of 0.96 (95% CI 0.80 to 1.00) (very low-certainty evidence) for assessing incomplete debulking with residual disease > 1 cm. In the last study, the sensitivity for assessing incomplete debulking with residual disease of > 2 cm on conventional MRI was 0.91 (95% CI 0.59 to 1.00) and the specificity 0.97 (95% CI 0.87 to 1.00) (very low-certainty evidence). Overall, the certainty of evidence was very low to moderate (according to GRADE), mainly due to small sample sizes and imprecision.

AUTHORS' CONCLUSIONS

Studies suggested a high specificity and moderate sensitivity for FDG-PET/CT and MRI to assess macroscopic incomplete debulking. However, the certainty of the evidence was insufficient to advise routine addition of FDG-PET/CT or MRI to clinical practice..In a research setting, adding an alternative imaging method could be considered for women identified as suitable for primary debulking by abdominal CT, in an attempt to filter out false-negatives (i.e. debulking, feasible based on abdominal CT, unfeasible at actual surgery).

Malignant peritoneal mesothelioma: a review

Malignant peritoneal mesothelioma (MPM) is a very rare malignancy of the peritoneum and has a poor prognosis. Of all mesotheliomas, pleural mesothelioma is more common than MPM. In comparison to pleural mesothelioma, the link with asbestos exposure is weaker (33-50% vs. >80%), but it is still the best-defined risk factor. MPM spreads predominantly expansive rather than infiltrative and symptoms are related to tumor spread within the abdominal cavity. Often, MPM is encountered incidentally by diagnostic imaging or by surgery. Computed tomography scan is widely accepted as a first line modality in diagnostic imaging. In diagnostic histopathology, MPM presents some challenges. Firstly, adequate clinical information is of utmost importance to consider the possibility of the diagnosis of MPM. Furthermore, a few morphological subtypes and variants exist. The most sensitive immunohistochemical markers are calretinin (100%), WT1 (94%) and CK5/6 (89%). The malignant character of immunohistochemically demonstrated mesothelial cells is not always obvious. This paradigm somewhat changed with the advent of immunohistochemical demonstration of BAP1 (BRCA-1 associated protein 1). Loss of BAP1 expression supports a diagnosis of malignancy. The gold standard in treatment remains cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC). Targetable molecular pathways in MPM are being identified. An exciting finding was the demonstration of ALK rearrangements in a small subset of patients with MPM and it is hoped for that at least this small subgroup of patients could benefit from treatment with ALK inhibitors. First-generation tyrosine kinase inhibitors against epidermal growth factor receptor (EGFR) did not show any significant activity in MPM. In contrast, nintedanib, an angiokinase inhibitor, improved progression-free survival and bevacizumab, a humanized anti-VEGF antibody increased overall survival in patients with MPM, when administered in combination with cisplatin and pemetrexed. Ongoing immunotherapy trials will offer a possible new treatment.

Peritoneal Metastases from Malignant Mesothelioma

Diffuse malignant peritoneal mesothelioma (MPM) is a rare cancer that is ultimately fatal in almost all afflicted individuals. Morbidity and mortality from MPM is due to its propensity to progress locoregionally within the abdominal cavity. Patients with MPM most commonly present with nonspecific abdominal symptoms that usually lead to diagnosis when the condition is relatively advanced. MPM is considered a chemotherapy-resistant malignancy.

Treatment of peritoneal carcinomatosis with Pressurized IntraPeritoneal Aerosol Chemotherapy - PIPAC-OPC2

BACKGROUND

Peritoneal carcinomatosis (PC) is a common endpoint in both gastrointestinal and non-gastrointestinal cancers, and PC is treated as other systemic metastases - unfortunately with disappointing results and considerable side-effects. Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC) is a new method of applying traditional chemotherapy, and preliminary data indicate that PIPAC is safe, able to stabilize or improve quality of life, and can induce an objectively measurable reduction in disease burden in PC.

METHODS

PIPAC-OPC2 is a prospectively controlled Phase II, single center, one-arm, open-label clinical trial investigating the treatment effect of PIPAC in patients with histological or cytological proven PC from gastrointestinal, ovarian or primary peritoneal cancer. Eligible patients will receive PIPAC in series of three using a combination of doxorubicin (1.5 mg/m2) and cisplatin (7.5 mg/m2) for non-colorectal cancer patients (PIPAC C/D), and oxaliplatin (92 mg/m2) in patients with PC of colorectal origin (PIPAC OX). Patients are monitored by: (1) repeated measurements of the Peritoneal Regression Grading Score (PRGS) in biopsies obtained from metal clips marked areas, (2) Quality-of-Life (QoL) questionnaires, (3) Magnetic Resonance Imaging (MRI) and (4) Prognostic Nutritional Index (PNI). Adverse events and surgical complications will be recorded according to the 30 days definition.

RESULTS

The primary outcome of PIPAC-OPC2 is to evaluate if PIPAC can induce major or complete response (PRGS 1 or 2) within a series of three PIPAC procedures. Secondarily this study investigates changes in QoL and MRI as a staging and response evaluation tool. The secondary outcomes will be used to create a model that may predict which of the patients will benefit from PIPAC treatment.

CONCLUSIONS

It is expected that PIPAC directed therapy can induce major or complete response in 50 % of patients with PC of colorectal origin and in 30 % of patients with PC of non-colorectal origin - and at the same time stabilize or even improve quality of life. This trial may provide data regarding the utility of MRI as a staging and response evaluation tool in patients with PC.

TRIAL REGISTRATION

The study is registered with ClinicalTrials.gov Identifier NCT03287375 and the European Clinical Trials Database (EudraCT) number 2016-003394-18.

Prospective, single-center implementation and response evaluation of pressurized intraperitoneal aerosol chemotherapy (PIPAC) for peritoneal metastasis

BACKGROUND

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a laparoscopy-guided administration of aerosolized chemotherapy. PIPAC seems to improve objective tumor response, survival and quality of life in patients with peritoneal metastasis. We assessed feasibility and efficacy of PIPAC in patients with peritoneal metastasis (PM).

METHODS

Patients were included in a prospective PIPAC protocol. Patients with colorectal PM were treated with oxaliplatin, patients with other primary tumors were treated with cisplatin and doxorubicin. Any chemotherapy exposure for healthcare workers was monitored by environmental and biological sampling. Feasibility was quantified by completion and complication rates. Response evaluation was documented by the peritoneal regression grading score (PRGS) and by peritoneal lavage cytology. Biopsy sites were marked by clips. Quality of life questionnaires were collected at baseline and after 60, 120 and 180 days.

RESULTS

A total of 35 patients with PM were treated with a median of three PIPAC procedures (range 1-9). Intraperitoneal access and completion of PIPAC was achieved in all patients. Few complications and adverse events were noted. There was no risk of chemotherapy exposure for healthcare workers. The mean PRGS was reduced significantly and a reduction of the PRGS was seen in 67% of the patients. Conversion from positive to negative cytology was achieved in 23% of the patients. Quality of life was stabilized from baseline to day 60.

CONCLUSIONS

PIPAC is feasible and well tolerated, may stabilize the quality of life in patients with end-stage PM and may induce histological and cytological regression.This study is registered at www.clinicaltrials.gov [ClinicalTrials.gov identifier: NCT02320448].

Preoperative assessment of peritoneal carcinomatosis of colorectal origin

The goal of preoperative assessment of patients with peritoneal carcinomatosis (PC) from colorectal origin is to select candidates for curative surgery by evaluating the possibility of complete resection, and to plan the surgical procedure. Quantitative and qualitative evaluation of lesional localization remains difficult even with current technical progress in imaging. Computed tomography (CT), the reference imaging technique, allows detection of both peritoneal and extra-peritoneal lesions. Sensitivity and specificity for detecting PC are 83% (95%CI: 79-86%) and 86% (95%CI: 82-89%), respectively. Functional imaging, with diffusion-weighted magnetic resonance imaging (MRI) and positron emission tomography PET-CT allows efficient exploration of peritoneal lesions. MRI is operator-dependent, with a long learning curve, and is, at present, essentially used only in expert centers. A standardized protocol provided by the radiologists working with the French National Center for rare peritoneal tumors RENA-RAD (http://www.renape-online.fr/fr/espace-professionnel/rena-rad.html) is however available on line. PET-CT is particularly useful for identifying and defining extra-peritoneal disease. Combining imaging techniques, particular CT with MRI, seems to improve the calculation of the Peritoneal Cancer Index compared to CT alone. Surgical exploration is the reference technique to evaluate PC. Currently, the literature cannot confirm whether laparoscopy performs as well as laparotomy, but laparoscopy is, de facto, the fundamental tool to decrease the number of unnecessary laparotomies in these patients. To optimize the pre-, intra- and postoperative reporting of the extent of PC, the French National Network for management of PC (RENAPE and BIG-RENAPE: http://www.e-promise.org/) has offered on-line a free-of-charge, standardized, multidisciplinary and transversal software.