Accuracy of radiologic- laparoscopic peritoneal carcinomatosis categorization in the prediction of surgical outcome

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.

Association between the quantitative characteristics of dual-energy spectral CT and cytoreduction surgery outcome in patients with advanced epithelial ovarian cancers: A prospective observational study

This study aimed to explore the association between the quantitative characteristics of dual-energy spectral CT and cytoreduction surgery outcome in patients with advanced epithelial ovarian carcinoma (EOC). In this prospective observational study, patients with advanced EOC (federation of gynecology and obstetrics stage III-IV) treated in the Department of Gynecological Oncology at our Hospital between June 2021 and March 2022 were enrolled. All participants underwent dual-energy spectral computed tomography (DECT) scanning 2 weeks before cytoreductive surgery. The quantitative data included peritoneal cancer index (PCI) determined by DECT, CT value at 70 keV, normalized iodine concentration, normalized water concentration, effective atomic number (effective-Z), and slopes of the spectral attenuation curves (slope λ Hounsfield unit). Fifty-five participants were included. The patients were 57.2 ± 9.8 years of age, and 72.7% were menopausal. The maximal diameter of tumors was 8.6 (range, 2.9-19.7) cm, and 76.4% were high-grade serous carcinomas. Optimal cytoreduction was achieved in 43 patients (78.2%). Compared with the optimal cytoreductive group, the suboptimal cytoreductive group showed a higher PCI (median, 21 vs 6, P < .001), higher 70 keV CT value (69.5 ± 16.6 vs 57.1 ± 13.0, P = .008), and higher slope λ Hounsfield unit (1.89 ± 0.66 vs 1.39 ± 0.60, P = .015). The multivariable analysis showed that the PCI (OR = 1.74, 95%CI: 1.24-2.44, P = .001) and 70 keV CT value (OR = 1.07, 95%CI: 1.01-1.13, P = .023) were independently associated with a suboptimal cytoreductive surgery. The area under the receiver operating characteristics curve of PCI and 70 keV CT value was 0.903 (95%CI: 0.805-1.000, P = .000) and 0.740 (95%CI: 0.581-0.899, P = .012), respectively. High PCI and 70 keV CT value are independently associated with suboptimal cytoreductive surgery in patients with advanced EOC. The PCI determined by DECT might be a better predictor for suboptimal cytoreduction.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Head-To-Head Comparison of 68Ga-FAPI PET/CT and FDG PET/CT for the Detection of Peritoneal Metastases: Systematic Review and Meta-Analysis

BACKGROUND. FDG PET/CT has limited diagnostic performance in the detection of peritoneal metastasis (PM). Gallium-68-labeled fibroblast activation protein inhibitor (FAPI) targets tumor stroma, leading to high accumulation across cancer types. OBJECTIVE. The purpose of this study was to conduct a meta-analysis to compare the diagnostic performances of ⁶⁸Ga-FAPI PET/CT and FDG PET/CT in detecting PM on the basis of studies providing head-to-head comparisons between the two tests. EVIDENCE ACQUISITION. PubMed, Embase, and Cochrane Library databases were searched through July 2022 to identify studies reporting head-to-head comparison of ⁶⁸Ga-FAPI PET/CT and FDG PET/CT for detection of PM. The reference standard was classified as histopathology for all patients or as a combination of histopathologic, clinical, imaging, laboratory, and follow-up information (multidisciplinary reference standard). A random-effects statistical model was applied to conduct a meta-analysis of the diagnostic performances of the tests in patient-based and lesion-based analyses. The QUADAS-2 and QUADAS Comparative tools were used to assess study quality. EVIDENCE SYNTHESIS. Eleven studies were included. Patient-based analysis was reported in nine studies including 340 patients, and lesion-based analysis was reported in four studies including 222 lesions. The pooled sensitivity of ⁶⁸Ga-FAPI PET/CT was significantly higher than that of FDG PET/CT in patient-based analysis (98.2% [95% CI, 96.1-100.0%] vs 55.9% [95% CI, 33.9-77.9%]) and lesion-based analysis (99.9% [95% CI, 99.5-100.0%] vs 27.3% [95% CI, 11.2-43.4%]). Eight studies were rated at high risk of bias in the reference standard domain because the multidisciplinary reference standard was not sufficiently explained and may have included one of the two index tests, which would have artificially increased sensitivity. In three studies specificity was reported as 100.0% for both tests; these studies were considered at uncertain risk of bias in the patient selection domain because patients with benign peritoneal conditions may have been excluded, resulting in underestimation of potential false-positive results. CONCLUSION. The current evidence suggests excellent sensitivity of ⁶⁸Ga-FAPI PET/CT for the detection of PM in comparison with poorer sensitivity of FDG PET/CT. However, most included studies had high risk of bias. Further studies are needed to more convincingly characterize true- and false-positive results. CLINICAL IMPACT. The sensitivity of ⁶⁸Ga-FAPI PET/CT may be substantially greater than that of FDG PET/CT for the evaluation of PM, facilitating surgical planning and candidate selection.

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.

Role of Computed Tomography in the Evaluation of Peritoneal Carcinomatosis

Peritoneal carcinomatosis (PC) refers to metastatic spread of tumor into the peritoneal cavity. Earlier, PC was thought to be associated with grave clinical outcome. However, various advances in treatment options including cytoreductive surgery and heated intraperitoneal chemotherapy or early post-operative chemotherapy can prolong survival of patients with peritoneal carcinomatosis. These treatment options are associated with high morbidity and mortality. The purpose of this article is to acquaint the radiologist about various appearances of peritoneal carcinomatosis in order to help clinicians in selecting candidates for surgery and avoid unnecessary potentially debilitating surgeries in patients with unresectable PC.

Diagnosis and treatment of peritoneal carcinomatosis - a comprehensive overview

Peritoneal carcinomatosis, which is the most common malignant process of the peritoneal cavity, originates mostly from colorectal, gastric, and gynaecological malignancies. The differential diagnosis is broad and covers primary peritoneal malignancies, as well as many benign disorders such as endometriosis, and inflammatory and infectious diseases. Peritoneal implants tend to locate in the areas of the physiological stasis of the peritoneal fluid: pelvic peritoneal reflections, right and left paracolic gutters, superior part of the sigmoid mesocolon, ileocolic area, and the right subdiaphragmatic space. The 3 most common imaging findings are ascites, nodular implants, and infiltration of the peritoneal fatty tissue. Several imaging modalities may be applied in patients with peritoneal carcinomatosis. Ultrasound has low sensitivity and specificity, and therefore plays only a marginal role. Computed tomography is the method of choice, due to its availability, cost-effectiveness, and relatively high sensitivity. The sensitivity of magnetic resonance imaging depends on the size of peritoneal implants - in cases of implants larger than 10 mm is comparable to CT. Some studies suggest that PET/CT may be the most sensitive method, yet its usefulness in everyday practice is controversial. The Peritoneal Carcinomatosis Index (PCI) is a scale used to assess the tumour burden in the peritoneum and may serve as a communication tool between clinicians and radiologists. The imaging findings may influence the surgeon's decision on performing cytoreductive surgery, which may be followed by intraperitoneal chemotherapy (HIPEC or EPIC procedures). The introduction of these therapeutic methods has significantly improved the life expectancy of patients with peritoneal carcinomatosis.

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.

Multidetector computed tomography in diagnosing peritoneal metastases in ovarian carcinoma

Multidetector computed tomography (MDCT) of the abdomen is currently the imaging examination of choice for the staging and follow-up of ovarian carcinoma (OC). Peritoneal metastases (PMs) represent the most common pathway for the metastatic spread of OC. MDCT scanners, due to several advantages-including increased volume coverage, reduced scanning time, acquisition of thin slices and creation of multiplanar reformations, and three-dimensional reconstructions-provide useful information regarding the early and accurate detection of PMs. Detailed mapping of peritoneal carcinomatosis is feasible, with improved detection of sub-centimeter peritoneal implants and thorough evaluation of curved peritoneal surfaces.

CT imaging of peritoneal carcinomatosis with surgical correlation: a pictorial review

Cytoreductive surgery in combination with hyperthermic intraperitoneal chemotherapy has revolutionized the survival and the quality of life in selected patients with peritoneal carcinomatosis. Preoperative CT is important for the selection of patients that may benefit from cytoreductive surgery and is useful for surgical planning. There are several tasks for the radiologist during CT interpretation: to describe cancerous implants on a "site-by-site" basis in the peritoneum, ligaments, mesenteries and visceral surfaces, to analyze patterns of involvement and to estimate the disease burden. Knowledge of the correlation between the CT and the surgical findings enhances the understanding of the disease and facilitates the communication between radiologists and surgeons.

Malignant Bowel Obstruction Management Over Time: Are We Doing Anything New? A Current Narrative Review

INTRODUCTION

Malignant bowel obstruction from peritoneal carcinomatosis affects a significant proportion of luminal gastrointestinal and ovarian oncology patients, and portends poor long-term survival. The management approach for these patients includes a range of medical therapies and surgical options; however, how to select an optimal treatment strategy remains enigmatic. The goal of this narrative review was to summarize the latest evidence around multimodal malignant bowel obstruction treatment and to establish if and where progress has been made.

METHODS

A targeted literature search examining articles focused on the management of malignant bowel obstruction from peritoneal carcinomatosis was performed. Following data extraction, a narrative review approach was selected to describe evidence and guidelines for surgical prognostic factors, imaging, tube decompression, medical management, nutrition, and quality of life.

RESULTS

Outcomes in the literature to date are summarized for various malignant bowel obstruction treatment strategies, including surgical and non-surgical approaches, as well as a discussion of the role of total parenteral nutrition and chemotherapy in holistic malignant bowel obstruction management.

CONCLUSION

There has been little change in survival outcomes in malignant bowel obstruction in over more than a decade and there remains a paucity of high-level evidence to direct treatment decision making. Healthcare providers treating patients with malignant bowel obstruction should work to establish consensus guidelines, where feasible, to support medical providers in ensuring compassionate care during this often terminal event for this unique patient group.

Role of [68Ga]Ga-DOTA-FAPI-04 PET/CT in the evaluation of peritoneal carcinomatosis and comparison with [18F]-FDG PET/CT

PURPOSE

The aim of this study was to explore the role of [⁶⁸Ga]Ga-DOTA-FAPI-04 positron emission tomography/computed tomography (PET/CT), compared with ¹⁸F-fluorodeoxyglucose [¹⁸F]-FDG PET/CT, for evaluating peritoneal carcinomatosis in patients with various types of cancer.

METHODS

Patients with suspected peritoneal malignancy, who underwent both [¹⁸F]-FDG and [⁶⁸Ga]Ga-DOTA-FAPI-04 PET/CT between October 2019 and August 2020, were retrospectively analysed. The radiotracer uptake, peritoneal cancer index (PCI) score, and diagnostic performance of [¹⁸F]-FDG and [⁶⁸Ga]Ga-DOTA-FAPI-04 PET/CT were evaluated and compared.

RESULTS

Our cohort consisted of 46 patients, including 16 patients with diffuse-type peritoneal carcinomatosis, 27 with nodular-type peritoneal carcinomatosis, and 3 true-negative patients. A significant difference in standard uptake values (SUV) of lesions between [¹⁸F]-FDG and [⁶⁸Ga]Ga-DOTA-FAPI-04 PET/CT examination was observed (median SUV: 3.48 vs. 9.82; P < 0.001), particularly in peritoneal carcinomatosis from gastric cancer (median SUV: 3.44 vs. 8.05; P = 0.001). Moreover, [⁶⁸Ga]Ga-DOTA-FAPI-04 PET/CT showed a higher PCI score and better sensitivity than [¹⁸F]-FDG PET/CT for the detection of peritoneal carcinomatosis (6 vs. 18; P < 0.001; 72.09% vs. 97.67%; P = 0.002).

CONCLUSION

[⁶⁸Ga]Ga-DOTA-FAPI-04 PET/CT demonstrated superior sensitivity over [¹⁸F]-FDG PET/CT for the detection of peritoneal carcinomatosis in patients with various types of cancer, particularly gastric cancer. Furthermore, the uptake of [⁶⁸Ga]Ga-DOTA-FAPI-04 in peritoneal carcinomatosis was significantly higher than that of [¹⁸F]-FDG, demonstrating a larger extent of the lesions and yielding a higher PCI score. This could help enhance the image contrast, improve physicians' diagnostic confidence, and reduce the proportion of missed diagnoses.

Correlation of surgeon radiology assessment with laparoscopic disease site scoring in patients with advanced ovarian cancer

BACKGROUND

Radiographic triage measures in patients with new advanced ovarian cancer have yielded inconsistent results.

OBJECTIVE

To determine the correlation between surgeon radiology assessment and laparoscopic scoring by disease sites in patients with newly diagnosed advanced stage ovarian cancer.

METHODS

Fourteen gynecologic oncology surgeons from a single institution performed a blinded review of pre-operative contrast-enhanced CT imaging from patients with advanced stage ovarian cancer. Each of the patients had also undergone laparoscopic scoring assessment, between April 2013 and December 2017, to determine primary resectability using the validated Fagotti scoring method, and assigned a predictive index value score. Surgeons were asked to provide expected predictive index value scores based on their blinded review of the antecedent CT imaging. Linear mixed models were conducted to calculate the correlation between radiologic and laparoscopic score for surgeons individually, and as a group. Once the model was fit, the inter-class correlation and 95% CI were calculated.

RESULTS

Radiology review was performed on 20 patients with advanced stage ovarian cancer who underwent laparoscopic scoring assessment. Surgeon faculty rank included assistant professor (n=5), associate professor (p=4), and professor (n=5). The kappa inter-rater agreement was -0.017 (95% CI -0.023 to -0.005), indicating low inter-rater agreement between radiology review and actual laparoscopic score. The inter-class correlation in this model was 0.06 (0.02-0.21), indicating that surgeons do not score the same across all the images. When using a clinical cut-off point for the predictive index value of 8, the probability of agreement between radiology and actual laparoscopic score was 0.56 (95% CI 0.49 to 0.73). Examination of disease site sub-scales showed that the probability of agreement was as follows: peritoneum 0.57 (95% CI 0.51 to 0.62), diaphragm 0.54 (95% CI 0.48 to 0.60), mesentery 0.51 (95% CI 0.45 to 0.57), omentum 0.61 (95% CI 0.55 to 0.67), bowel 0.54 (95% CI 0.44 to 0.64), stomach 0.71 (95% CI 0.65 to 0.76), and liver 0.36 (95% CI 0.31 to 0.42). The number of laparoscopic scoring cases, tumor reductive surgery cases, or faculty rank was not significantly associated with overall or sub-scale agreement.

CONCLUSIONS

Surgeon radiology review did not correlate highly with actual laparoscopic scoring assessment findings in patients with advanced stage ovarian cancer. Our study highlights the limited accuracy of surgeon radiographic assessment to determine resectability.