Detection of histologically proven peritoneal carcinomatosis with fused 18F-FDG-PET/MDCT

The role of subspecialized radiologist reviews in preoperative conference for hepato-pancreato-biliary disease

PURPOSE

To identify the role of subspecialized radiologists in preoperative conferences of radiologists and surgeons in the management of hepato-pancreato-biliary (HPB) diseases.

METHODS

We retrospectively evaluated the prospective data of 247 patients (mean age, 63.8 years; 173 men) who were referred for preoperative conferences (n = 258; 11 were discussed twice) for HPB disease between September 2021 and April 2022. Before each preoperative conference, subspecialized radiologists reviewed all available imaging studies and treatment plan information. After each conference, any change to the treatment plan was documented (major, minor, or none). Additional information provided by the radiologists was collected (significant, supplementary, or none). Uni- and multivariable analyses were performed to determine factors that resulted in a major change to the treatment plan.

RESULTS

Of the 258 reviewed cases, a major change was made to the treatment plan in 26 cases (10.1 %) and a minor change in 41 (15.9 %). Significant information was provided in 27 cases (10.5 %) and supplementary information in 72 (27.9 %). In the multivariable analysis, additional information about local tumor extent (odds ratio [OR], 6.3; 95 % confidence interval [CI], 2.1-19.5; p = 0.001) and distant metastasis detection (OR, 33.2; 95 % CI, 5.1-216.6; p < 0.001) was significantly associated with a major change.

CONCLUSION

The involvement of subspecialized radiologists in preoperative conferences resulted in major treatment plan changes in 10.1 % of the cases, primarily associated with the added information about local tumor extent and distant metastasis.

Repair and remodeling of the mandibular head of the condylar process in four immature dogs

Spontaneous repair and remodeling of the mandibular head of the condylar process is a rarely reported outcome following condylectomy. This clinical report describes the spontaneous repair and subsequent remodeling of the mandibular head of the condylar process in four immature dogs that sustained traumatic injuries, necessitating surgical intervention through arthroplasty via partial or complete condylectomy, or caudal mandibulectomy. In subsequent evaluations, it was observed that all dogs exhibited clinically functional TMJs, as evidenced by an appropriate range of motion. These findings were corroborated by the owners' reports of the patient's normal eating and drinking abilities. Conventional and cone-beam computed tomography studies demonstrated the repair and remodeling of the osseous tissues of the mandibular head of the condylar process. Histopathology was unavailable to assess the novel tissues. No evidence of intraarticular or extraarticular ankylosis or osteoarthritic changes was observed.

Positron Emission Tomography/Magnetic Resonance Imaging (PET/MRI) Versus the Standard of Care Imaging in the Diagnosis of Peritoneal Carcinomatosis

OBJECTIVE

To compare positron emission tomography (PET)/magnetic resonance imaging (MRI) to the standard of care imaging (SCI) for the diagnosis of peritoneal carcinomatosis (PC) in primary abdominopelvic malignancies.

SUMMARY BACKGROUND DATA

Identifying PC impacts prognosis and management of multiple cancer types.

METHODS

Adult subjects were prospectively and consecutively enrolled from April 2019 to January 2021. Inclusion criteria were: 1) acquisition of whole-body contrast-enhanced (CE) 18F-fluorodeoxyglucose PET/MRI, 2) pathologically confirmed primary abdominopelvic malignancies. Exclusion criteria were: 1) greater than 4 weeks interval between SCI and PET/MRI, 2) unavailable follow-up. SCI consisted of whole-body CE PET/computed tomography (CT) with diagnostic quality CT, and/or CE-CT of the abdomen and pelvis, and/or CE-MRI of the abdomen±pelvis. If available, pathology or surgical findings served as the reference standard, otherwise, imaging followup was used. When SCI and PET/MRI results disagreed, medical records were checked for management changes. Follow-up data were collected until August 2021.

RESULTS

One hundred sixty-four subjects were included, 85 (52%) were female, and the median age was 60 years (interquartile range 50-69). At a subject level, PET/MRI had higher sensitivity (0.97, 95% CI 0.86-1.00) than SCI (0.54, 95% CI 0.37-0.71), P < 0.001, without a difference in specificity, of 0.95 (95% CI 0.90-0.98) for PET/MRI and 0.98 (95% CI 0.93-1.00) for SCI, P ¼ 0.250. PET/MRI and SCI results disagreed in 19 cases. In 5/19 (26%) of the discordant cases, PET/MRI findings consistent with PC missed on SCI led to management changes.

CONCLUSION

PET/MRI improves detection of PC compared with SCI which frequently changes management.

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.

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.

The BUMPy road of peritoneal metastases in ovarian cancer

Ovarian cancer is the most common cause of death due to gynecologic malignancies, with more than 70% of patients presenting with advanced stage disease at the time of diagnosis. The extent and distribution of tumor guide primary treatment selection and clinical management. While primary cytoreductive surgery with complete tumor resection improves survival, patients with extensive peritoneal disease may benefit from neoadjuvant chemotherapy first to reduce tumor burden followed by interval cytoreductive surgery. Imaging plays an essential role in triaging patients including selecting patients who may benefit from neoadjuvant chemotherapy before cytoreductive surgery. Interestingly, there are no universally established criteria to predict resectability and local practices depend on local guidelines and surgeon preferences. Nevertheless, certain anatomical tumor locations are known to be difficult to resect and are associated with suboptimal cytoreduction or require special surgical considerations. This review discusses the recent advances in the initial management of patients with ovarian cancer, a practical approach to the assessment and communication of peritoneal metastases locations on CT and MRI. It also explores recent advances in genomics profiling and radiomics that may influence the initial management of these patients.

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

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

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

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

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.

Primary peritoneal serous carcinoma: a primer for radiologists

Primary peritoneal serous carcinoma (PPSC) is a rare primary peritoneal tumor characterized by a unique range of clinical features and imaging findings. Though it shares many clinical, histologic, and imaging features with serous ovarian carcinoma, it remains a distinct clinical entity. Although less common than its primary ovarian counterpart, PPSC is characterized by a prognosis that is often equally poor with presentations common in late stages of disease. Key imaging modalities used in the evaluation of PPSC include ultrasound, CT, MRI, and PET/CT. For radiologists, an understanding of the pertinent imaging findings, pathologic correlations, and clinical features of PPSC is essential for arriving at the correct diagnosis and guiding the subsequent appropriate management of this complex malignancy.

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.

Splenosis Mimicking Peritoneal Seeding of Advanced Colon Cancer Can Be Identified by Spleen SPECT/CT and FDG PET/CT

This case report demonstrates that Tc-99m labeled heat-damaged red blood cell single-photon emission computed tomography/computed tomography (spleen SPECT/CT) and F-18 fluorodeoxyglucose positron emission tomography/CT (FDG PET/CT) could noninvasively confirm splenosis mimicking peritoneal seeding of advanced sigmoid colon cancer with hepatic metastases, and played a crucial role in determining the treatment plan.

To Enhance or Not to Enhance? The Role of Contrast Medium 18F-FDG PET/CT in Recurrent Ovarian Carcinomas

Background and Objectives: ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/X-ray computed tomography (PET/CT) represents the mainstay diagnostic procedure for suspected ovarian cancer (OC) recurrence. PET/CT can be integrated with contrast medium and in various diagnostic settings; however, the effective benefit of this procedure is still debated. We aimed to compare the diagnostic capabilities of low-dose and contrast-enhanced PET/CT (PET/ldCT and PET/ceCT) in patients with suspected ovarian cancer relapse. Materials and Methods: 122 OC patients underwent both PET/ldCT and PET/ceCT. Two groups of nuclear medicine physicians and radiologists scored the findings as positive or negative. Clinical/radiological follow-up was used as ground truth. Sensitivity, specificity, negative/positive predictive value, and accuracy were calculated at the patient and the lesion level. Results: A total of 455 and 474 lesions were identified at PET/ldCT and PET/ceCT, respectively. At the lesion level, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were not significantly different between PET/ldCT and PET/ceCT (98%, 93.3%, 97.4%, 94.9%, and 96.9% for PET/ldCT; 99%, 95.5%, 98.3%, 97%, and 98% for PET/ceCT, p = ns). At the patient level, no significant differences in these parameters were identified (e.g., p = 0.22 and p = 0.35 for accuracy, in the peritoneum and lymph nodes, respectively). Smaller peritoneal/lymph node lesions close to physiological FDG uptake sources were found in the cases of misidentification by PET/ldCT. PET/ceCT prompted a change in clinical management in four cases (3.2%) compared to PET/ldCT. Conclusions: PET/ceCT does not perform better than PET/ldCT but can occasionally clarify doubtful peritoneal findings on PET/ldCT. To avoid unnecessary dose to the patient, PET/ceCT should be excluded in selected cases.

Peritoneal Lymphomatosis: The Great Mimicker

Peritoneal lymphomatosis (PL) is defined as intraperitoneal dissemination of lymphoma. Although rare, it is associated with high-grade lymphomas and can be easily mistaken for peritoneal carcinomatosis (PC) on imaging, which is a common condition associated with gastrointestinal and gynecological malignancies. Both PL and PC share similar radiographic features, however, they differ considerably in terms of prognosis and management. We present a case of a 58-year-old male with abdominal distention and ascites, initially reported as having PC on imaging. A subsequent peritoneal biopsy revealed PL secondary to a low-grade follicular lymphoma. Since PL responds well to chemotherapy, its prompt diagnosis and differentiation from PC helps avoid unnecessary surgery.

[Radiologic Evaluation for Resectability of Pancreatic Adenocarcinoma]

Imaging studies play an important role in the detection, diagnosis, assessment of resectability, staging, and determination of patient-tailored treatment options for pancreatic adenocarcinoma. Recently, for patients diagnosed with borderline resectable or locally advanced pancreatic cancers, it is recommended to consider curative-intent surgery following neoadjuvant or palliative therapy, if possible. This review covers how to interpret imaging tests and what to consider when assessing resectability, diagnosing distant metastasis, and re-assessing the resectability of pancreatic cancer after neoadjuvant or palliative therapy.

The Role of Imaging in Current Treatment Strategies for Pancreatic Adenocarcinoma

In pancreatic cancer, imaging plays an essential role in surveillance, diagnosis, resectability evaluation, and treatment response evaluation. Pancreatic cancer surveillance in high-risk individuals has been attempted using endoscopic ultrasound (EUS) or magnetic resonance imaging (MRI). Imaging diagnosis and resectability evaluation are the most important factors influencing treatment decisions, where computed tomography (CT) is the preferred modality. EUS, MRI, and positron emission tomography play a complementary role to CT. Treatment response evaluation is of increasing clinical importance, especially in patients undergoing neoadjuvant therapy. This review aimed to comprehensively review the role of imaging in relation to the current treatment strategy for pancreatic cancer, including surveillance, diagnosis, evaluation of resectability and treatment response, and prediction of prognosis.

Molecular Imaging of Peritoneal Carcinomatosis in Ovarian Carcinoma

OBJECTIVE. This article discusses the emerging roles of ¹⁸F-FDG PET/CT and DWI in the assessment of peritoneal carcinomatosis in ovarian carcinoma from diagnostic accuracy to disease prognostication with gross pathologic correlation. CONCLUSION. PET/CT and DWI have incremental clinical values over conventional modalities with high predictive values of incomplete cytoreduction in ovarian carcinoma. The respective quantitative metrics offer evaluation of tumor burden with prognostic value in ovarian carcinoma.

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.

Diagnostic accuracy of 18F-FDG PET/CT for detection of peritoneal carcinomatosis; a systematic review and meta-analysis

OBJECTIVE

The current review aimed to investigate the performance of the diagnostic accuracy of ¹⁸F- fludeoxyglucose positron emission tomography/CT (PET/CT) in detecting peritoneal carcinomatosis (PC) through a systematic review and meta-analysis.

METHODS

The MEDLINE via PubMed and EMBASE from the earliest available date of indexing to 31 March 2017, were searched for studies evaluating the diagnostic performance of ¹⁸F-FDG PET/CT in detecting PC. We evaluated the pooled sensitivities and specificities across included studies, calculated positive and negative likelihood ratios (LR+ and LR-), and plotted summary receiver operating characteristic curves. Deek's funnel plot asymmetry tests were used to assess the possible underlying publication bias.

RESULTS

The current meta-analysis demonstrated no significant publication bias (p = 0.21). Across 14 studies (671 patients), the overall sensitivity of ¹⁸F-FDG PET/CT was 0.87 [95% CI (0.77-0.93)] with heterogeneity (χ² = 94.2, p = 0.00) and a pooled specificity of 0.92 [95% CI; (0.89-0.94)] with heterogeneity (χ² = 20.6, p = 0.08). LR syntheses gave an overall LR+ of 10.4 [95% CI (7.5-14.5)] and LR- of 0.14 [95% CI (0.08-0.26)]. The pooled diagnostic odds ratio was 73 [95% CI (34-159)]. In univariate meta-regression analysis, publication year and cohort homogeneity were the potent sources of heterogeneity. However, in multivariate meta-regression, no definite variable was the source of the study heterogeneity.

CONCLUSION

¹⁸F-FDG PET/CT demonstrated good sensitivity and specificity for the detection of PC. Further large multicentre studies would be necessary to substantiate the diagnostic accuracy of ¹⁸F-FDG PET/CT for the diagnosis of PC in various cancers. Advances in knowledge: ¹⁸F-FDG PET/CT showed good diagnostic performance in the evaluation of PC and could provide additional information for that purpose in various cancers.

"PAUSE": a method for communicating radiological extent of peritoneal malignancy

Radiology reports of diffuse peritoneal disease should address key findings pertinent to the management of these patients. The reporting of radiology findings in patients with peritoneal malignancy is currently variable and poorly standardised. Using the acronym "PAUSE" we emphasise the key imaging features that a radiology report should include in a patient with peritoneal malignancy, focussing on the key elements determining feasibility and likely prognosis of surgery and potential benefits from cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). The term "PAUSE" incorporates the following: P, primary tumour and peritoneal carcinomatosis index (PCI) as estimated by imaging; A, ascites and abdominal wall involvement; U, unfavourable sites of involvement; S, small bowel and mesenteric disease; E, extra peritoneal metastases. Thus, "PAUSE" has the potential to standardise radiology reporting in this field.

F-18 FDG PET/CT metabolic tumor volume predicts overall survival in patients with disseminated epithelial ovarian cancer

OBJECTIVE

We evaluated the prognostic impact of quantitative assessment by maximum standardized uptake value (SUVmax), metabolic tumour volume (MTV) and tumour lesion glycolysis (TLG) on [F-18] FDG PET/CT for patients with peritoneal carcinomatosis from epithelial ovarian cancer (EOC).

METHODS

Thirty-one patients with EOC underwent PET/CT for an early restaging after cytoreductive surgery, having been diagnosed with carcinomatosis (before chemotherapy). The SUVmax, MTV (cm³; 42% threshold) and TLG (g) were registered on residual peritoneal lesions. The patients were followed up 20±12months thereafter. The PET/CT results were compared to overall survival (OS).

RESULTS

The Kaplan-Meier survival analysis for the SUVmax did not reveal significant differences in OS (p=0.48). The MTV survival analysis showed a significant higher OS in patients presenting with a higher tumour burden than those with less tumour burden (p=0.01; 26 vs. 14 months), whereas TLG exhibited a similar trend though not significant (p=0.06). Apart from chemo-resistance, the higher the MTV, the better will be the response to chemotherapy.

CONCLUSIONS

Quantitative assessment by MTV rather than by SUVmax and TLG on PET/CT may be helpful for stratifying patients who present with peritoneal carcinomatosis from EOC, in order to implement the appropriate therapeutic regimen.

Recommendations and consensus on the treatment of peritoneal metastases of colorectal origin: a systematic review of national and international guidelines

AIM

This systematic review aimed to provide an overview of (inter)national guidelines on the treatment of peritoneal metastases of colorectal cancer origin (PMCRC) and to determine the degree of consensus and available evidence with identification of topics for future research.

METHOD

A systematic search of MEDLINE, Embase, PubMed as well as Tripdatabase, National Guideline Clearinghouse, BMJ Best Practice and Guidelines International Network was performed to identify (inter)national guidelines and consensus statements from oncological or surgical societies on PMCRC. The quality of guidelines was assessed using the AGREE-II score. Topics followed by recommendations were extracted from the guidelines. The recommendations, highest level of supporting evidence and the degree of consensus were determined for each topic.

RESULTS

Twenty-one guidelines were included, in most (15) of which cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) was recommended in selected patients based on level 1b evidence. Substantial consensus was also reached on the benefit of multidisciplinary team discussion and the achievability of a (near) complete cytoreduction (CC0-1) without supporting evidence. Both evidence and consensus were lacking regarding other aspects including preoperative positron emission tomography/CT, second look surgery in high risk patients, the optimal patient selection for CRS/HIPEC, procedural aspects of HIPEC and (perioperative) systemic therapy.

CONCLUSION

In currently available guidelines, evidence and consensus on the treatment strategy for PMCRC are lacking. Updates of guidelines are ongoing and future (randomized) clinical trials should contribute to multidisciplinary and international consensus on treatment strategies for PMCRC.

What the Radiologist Should Know About Treatment of Peritoneal Malignancy

OBJECTIVE

The purpose of this article is to discuss the role of the radiologist in the treatment of peritoneal cancer, with focus placed on advanced treatment options and selection of patients with resectable disease for whom complete cytoreduction can be achieved.

CONCLUSION

Peritoneal cancers traditionally have been associated with significant morbidity and universal mortality; however, the management of such cancers has evolved substantially. Advanced treatment options, including cytoreductive surgery and intraperitoneal chemotherapy, are associated with significantly improved long-term patient survival. To ensure that patients benefit from aggressive multimodality treatments, the radiologist plays a pivotal role in the multidisciplinary team to ensure careful patient selection, identifying individuals with resectable disease for whom complete cytoreduction can be achieved.

Role of Imaging in Peritoneal Surface Malignancies

Imaging plays a vital role in the evaluation of peritoneal malignancies. The presence of peritoneal metastases (PM) alters tumor staging, with direct implications in treatment choice and prognosis. Cytoreductive surgery (CRS) and Hyperthermic intraperitoneal chemotherapy (HIPEC) as a combined modality treatment have led to prolonged survival and even cure in selected patients with PM. Better outcomes are seen in patients with limited disease spread. Therefore, early diagnosis of peritoneal tumor seeding is essential. Despite significant advancement of technology, assessment of the origin of PM is often difficult, due partly to the complex peritoneal anatomy and partly due to the complex overlap of imaging features. Multidetector CT (MDCT) is the main stay due to its wide availbility, rapid evaluation, robust technique and good resolution. Imaging plays a vital role in selecting patients for the combined modality treatment. MRI is not as popular as CT due to limited availability, time required for the study and lack of experience with interpreting the results. PET-CT is useful in ruling out extra peritoneal disease and it is the CT component that is more reliable for predicting the disease extent. This article reviews the current use of various imaging modalities in various stages of treatment of patients with PM especially those undergoing CRS and HIPEC.

Prediction of 5-year survival in advanced-stage ovarian cancer patients based on computed tomography peritoneal carcinomatosis index

OBJECTIVE

To evaluate whether the quantification of peritoneal metastases in advanced-stage ovarian cancer patients using the peritoneal carcinomatosis index, detected by CT (CT-PCI), correlates with the serum levels of tumor marker CA-125 and 5-year survival.

METHODS

The CT-PCI was determined in 82 patients with stage III or stage IV ovarian cancer using the Sugarbaker classification prior to cytoreductive surgery. Linear regression analysis was used to correlate CT-PCI and CA-125 levels. Correlation of presurgical CT-PCI, optimal surgical cytoreduction, and 5-year survival was established using binary logistic regression analysis. A score for prediction of 5-year survival probability was established using multivariate backwards binary logistic regression.

RESULTS

Presurgical CT-PCI correlates significantly with presurgical CA-125 serum levels (r = 0.487, P < 0.001). Multivariate binary logistic regression suggested significantly improved 5-year survival with lower CT-PCI and lower ECOG performance scores.

CONCLUSION

CT-PCI allows quantification of peritoneal disease in advanced-stage ovarian cancer patients, similar to CA-125. CT-PCI in combination with ECOG performance has the potential to help evaluate the 5-year survival probability.

Diagnostic and prognostic evaluation of fluorodeoxyglucose positron emission tomography/computed tomography and its correlation with serum cancer antigen-125 (CA125) in a large cohort of ovarian cancer patients

OBJECTIVE

We evaluated the efficacy of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in recurrent disease, response to therapy, and long-term follow-up of ovarian cancer (OC) patients in relation to cancer antigen-125 (CA125) levels and the prognostic meaning of this modality in this subset of subjects.

MATERIAL AND METHODS

Between 2005 and 2015, we retrospectively evaluated 125 patients affected by OC who underwent FDG PET/CT imaging at our institution. The indications for PET/CT were recurrence of disease in 78 patients, therapy response assessment in 29, and follow-up in 18. The results of FDG PET/CT were compared with those of histopathology and clinical and radiological progression during follow-up for at least 6 months. The median long-term follow-up was 33 months. The diagnostic accuracies for the different clinical settings were evaluated. The relationships among global survival (GS), FDG PET/CT results, and CA125 levels were evaluated by both Kaplan-Meier and Cox regression analysis.

RESULTS

CA125 results were positive (>35 UI/mL) in 62 patients and negative in 63 (49% vs. 51%). The sensitivity and specificity of CA125 were 72% and 91%, respectively. PET/CT imaging showed a sensitivity of 98.6% and a specificity of 77.8% for the assessment of recurrent disease, and a sensitivity of 72.7% and a specificity of 88.9% for therapy evaluation. Meanwhile, in 18 patients evaluated during follow-up, the specificity was 82.3%. GS was significantly higher in case of negative CA125 values at the time of FDG PET/CT, of a negative PET/CT scan and when no evidence of peritoneum recurrence and distant metastases was determined by PET. Multivariate regression analysis showed that only age and peritoneum recurrence as determined by PET were identified as independent predictors of poor prognosis.

CONCLUSION

Metabolic imaging with FDG PET/CT proved useful in patients where OC recurrence was suspected, even when the value of tumor marker CA125 was in a normal range. A positive PET/CT scan and the presence of peritoneum recurrence at PET were associated with a poor prognosis after approximately 30 months.

Oral gastrografin radiography for the evaluation of the functional impact of peritoneal carcinomatosis: Correlation with clinicopathological findings

This study was conducted to evaluate the functional impact of peritoneal carcinomatosis (PC) on the gastrointestinal system by oral gastrografin radiography (OGR). OGR was performed on 105 patients with PC from abdominal malignancies. The OGR characteristics were analyzed and compared with intraoperative observations. OGR provided real-time dynamic information on the functional impacts of PC. The OGR findings were normal in 9 (8.6%) and abnormal in 96 (91.4%) cases. In terms of frequency, 33 cases (31.4%) exhibited mild intestinal aggregation and flattening of the intestinal mucosa; 29 cases (27.6%) exhibited limited intestinal invasion, marginally stenotic small bowel and mucosal deformities; 26 cases (24.8%) exhibited only mild mesenteric contracture and mild slowing of gastrointestinal peristalsis; 5 cases (4.8%) exhibited obvious mesenteric contracture, ball-like changes, fixed position and disappearance of the intestinal mucosa; 2 cases (1.9%) exhibited complete pyloric obstruction; and 1 case (0.9%) exhibited duodenal obstruction. Gastric PC was associated with a higher percentage of stomach filling defects and small intestinal aggregates compared with PC from other malignancies (P<0.01 for both). In 87 cases, the ORG findings were in accordance with the intraoperative findings (κ=0.726, P<0.001), whereas 17 cases (16.2%) were underestimated and 1 (0.9%) was overestimated by OGR. This study indicated that OGR may be a useful technique for the evaluation of the functional impacts of PC on the gastrointestinal system and may help optimize the selection of patients for treatment.

Role of imaging in the pretreatment evaluation of common gynecological cancers

Different treatment options are available for patients with gynecological cancers. Imaging plays an important role in assessment of patients with common cancers involving uterine body, cervix and ovaries, from detection to evaluation of the extent of disease. The purpose of this review is to highlight the role of cross-sectional imaging techniques in treatment stratification and overall management of patients with endometrial, cervical and ovarian cancers. Several imaging techniques used are described, including ultrasound, computed tomography (CT), MRI and PET/CT. Specific imaging appearances of the most common uterine, cervical and ovarian cancers are discussed. Imaging findings corresponding to the 2009 revised International Federation of Gynecology and Obstetrics (FIGO) staging of gynecologic malignancies are also described. In the multidisciplinary evaluation of patients with gynecologic malignancies, the role of the radiologist has become central for accurate diagnosis and evaluation of extent of disease to achieve better treatment selection and planning.

Impact of pre-operative positron emission tomography in gallbladder cancer

BACKGROUND

Current pre-operative staging methods for gallbladder cancer (GBC) are suboptimal in detecting metastatic disease. Positron emission tomography (PET) may have a role but data are lacking.

METHODS

Patients with GBC and PET assessed by a hepatobiliary surgeon in clinic between January 2001 and June 2013 were retrospectively reviewed. Computed tomography (CT)/magnetic resonace imaging (MRI) were correlated with PET scans and analysed for evidence of metastatic or locally unresectable disease. Medical records were reviewed to determine if PET scanning was helpful by preventing non-therapeutic surgery or enabling resection in patients initially deemed unresectable.

RESULTS

There were 100 patients including 63 incidental GBC. Thirty-eight patients did not proceed to surgery, 35 were resected and 27 patients were explored but had unresectable disease. PET was positive for metastatic disease in 39 patients (sensitivity 56%, specificity 94%). Five patients definitively benefitted from PET: in 3 patients PET found disease not seen on CT, and 2 patients with suspicious CT findings had negative PET and successful resections. In a further 12 patients PET confirmed equivocal CT findings. Three patients had additional invasive procedures performed owing to PET avidity in other sites. Utility of PET was higher in patients with suspicious nodal disease on CT [odds ratio (OR) 7.1 versus no nodal disease, P = 0.0004], and in patients without a prior cholecystectomy (OR 3.1 versus post-cholecystectomy, P = 0.04).

CONCLUSION

Addition of PET to conventional cross-sectional imaging has a modest impact on management pre-operatively particularly in patients without a prior cholecystectomy and to confirm suspicious nodal disease on CT.

PET or PET/CT for detection of peritoneal carcinomatosis: a meta-analysis

The present study assessed the diagnostic performances of (18)F-FDG PET or PET/CT in detecting peritoneal carcinomatosis in patients with cancer.

METHODS

Through a search of MEDLINE (January 1998 to September 2012), an overall weighted average for sensitivity and specificity was calculated using the weighted averages of the sample sizes in each relevant study. Pooled estimates of positive and negative likelihood ratios were calculated using fixed and random effects models, respectively, according to the heterogeneity among studies. A summary receiver operating characteristics (sROC) curve was constructed and the area under the sROC curve (AUC) was calculated. To explore heterogeneity, due to sources other than threshold effects, I-square was calculated.

RESULTS

The present study included analyses of patients (n = 513) from 7 studies. Results indicated a significant heterogeneity for sensitivity and specificity (I(2) > 50% and P < 0.05). The overall pooled estimates for sensitivity and specificity of FDG PET or PET/CT scans in the detection of peritoneal carcinomatosis were 72.4% (95% CI, 64.4%-79.5%) and 96.7% (95% CI, 94.4%-98.3%), respectively. The positive likelihood ratio was 10.414 (95% CI, 6.195-17.506) and the negative likelihood ratio 0.312 (95% CI, 0.159-0.612). The AUC was 0.9404. The overall diagnostic accuracy (Q* index) was 87.8%.

CONCLUSION

The high specificity may provide the reliability of a positive FDG PET or PET/CT to detect peritoneal carcinomatosis in patients with cancer. FDG PET or PET/CT has only weak power to exclude the presence of peritoneal carcinomatosis. By a good overall diagnostic accuracy, FDG PET or PET/CT may prove beneficial to surgeons when selecting appropriate patients on whom to perform laparoscopy or laparotomy.

Whole-body MRI with diffusion-weighted sequence for staging of patients with suspected ovarian cancer: a clinical feasibility study in comparison to CT and FDG-PET/CT

OBJECTIVES

To evaluate whole-body MRI with diffusion-weighted sequence (WB-DWI/MRI) for staging and assessing operability compared with CT and FDG-PET/CT in patients with suspected ovarian cancer.

METHODS

Thirty-two patients underwent 3-T WB-DWI/MRI, (18) F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and CT before diagnostic open laparoscopy (DOL). Imaging findings for tumour characterisation, peritoneal and retroperitoneal staging were correlated with histopathology after DOL and/or open surgery. For distant metastases, FDG-PET/CT or image-guided biopsies were the reference standards. For tumour characterisation and peritoneal staging, WB-DWI/MRI was compared with CT and FDG-PET/CT. Interobserver agreement for WB-DWI/MRI was determined.

RESULTS

WB-DWI/MRI showed 94 % accuracy for primary tumour characterisation compared with 88 % for CT and 94 % for FDG-PET/CT. WB-DWI/MRI showed higher accuracy of 91 % for peritoneal staging compared with CT (75 %) and FDG-PET/CT (71 %). WB-DWI/MRI and FDG-PET/CT showed higher accuracy of 87 % for detecting retroperitoneal lymphadenopathies compared with CT (71 %). WB-DWI/MRI showed excellent correlation with FDG-PET/CT (κ = 1.00) for detecting distant metastases compared with CT (κ = 0.34). Interobserver agreement was moderate to almost perfect (κ = 0.58-0.91).

CONCLUSIONS

WB-DWI/MRI shows high accuracy for characterising primary tumours, peritoneal and distant staging compared with CT and FDG-PET/CT and may be valuable for assessing operability in ovarian cancer patients.

KEY POINTS

• Whole-body MRI with diffusion weighting (WB-DWI/MRI) helps to assess the operability of suspected ovarian cancer. • Interobserver agreement is good for primary tumour characterisation, peritoneal and distant staging. • WB-DWI/MRI improves mesenteric/serosal metastatic spread assessment compared with CT and FDG-PET/CT. • Retroperitoneal/cervical-thoracic nodal staging using qualitative DWI criteria was reasonably accurate. • WB-DWI/MRI and FDG-PET/CT showed the highest diagnostic impact for detecting thoracic metastases.

Peritoneal carcinomatosis in patients with ovarian cancer: enhanced CT versus 18F-FDG PET/CT

PURPOSE

The study aimed to evaluate the efficacy of PET/CT in detecting peritoneal carcinomatosis in patients with ovarian cancer and to compare the diagnostic accuracy of FDG PET/CT with that of enhanced abdominal CT.

METHODS

The medical records of 46 consecutive patients with ovarian cancer were reviewed, and the presence of peritoneal tumor on (18)F-FDG PET/CT and enhanced abdominal CT scans was also assessed. Imaging results were compared with the pathologic findings obtained by surgery.

RESULTS

Pathologic results were positive for peritoneal carcinomatosis in 26 patients and negative in 20 patients. PET/CT correctly detected 25 of 26 patients with peritoneal carcinomatosis and enhanced abdominal CT correctly detected 23 of 26 patients. Sensitivity and specificity for the diagnosis of peritoneal carcinomatosis were 96.2% and 90%, respectively, for PET/CT and 88.5% and 65%, respectively, for enhanced abdominal CT. The accuracy of PET/CT was statistically higher than that of enhanced abdominal CT (93.5% vs 78.3%, P = 0.039). Four distinctly abnormal PET/CT findings of single nodular, multiple nodular, diffuse, and mixed FDG uptakes were identified and corresponded to pathologic findings.

CONCLUSIONS

(18)F-FDG PET/CT imaging is efficient in the diagnosis of peritoneal carcinomatosis and its performance is superior to that of enhanced abdominal CT.

Peritoneal lymphomatosis: CT and PET/CT findings and how to differentiate between carcinomatosis and sarcomatosis

Peritoneal lymphomatosis is a rare manifestation of lymphoma, seen most frequently with non-Hodgkin lymphoma, and it is important to be familiar with this condition, because early diagnosis directly affects the management of patients. This review illustrates the spectrum of imaging findings in peritoneal lymphomatosis, highlighting the use of positron emission tomography/computed tomography, showing common and uncommon subtypes of lymphoma associated with this entity, and how to differentiate it from peritoneal carcinomatosis and peritoneal sarcomatosis.

Extraovarian primary peritoneal carcinoma: staging with 18F-FDG PET/CT

A 69-year-old woman who presented with left lower quadrant abdominal pain and elevated serum cancer antigen 125 (CA-125) levels was referred for an MRI and an (18)F-FDG PET/CT to evaluate a suspicious abdominal mass seen on ultrasound. PET/CT showed extensive, intensely FDG-avid, omental and pelvic peritoneal thickening with no suspicious ovarian or colon masses. Based on the PET/CT results, the patient had extensive debulking surgery and histopathological evaluation revealed an extraovarian primary peritoneal carcinoma (EOPPC). (18)F-FDG PET/CT may be useful in differentiating EOPPC from other types of peritoneal carcinomatosis, and in determining the extent of the disease to better guide surgical management and improve long term outcomes.

High incidence of peritoneal implants in recurrence of intra-abdominal cancer revealed by 18F-FDG PET/CT in patients with increased tumor markers and negative findings on conventional imaging

OBJECTIVE

The aim of this prospective study was to investigate the role of 18F-fluorodeoxyglucose (18F-FDG) PET/CT in the diagnosis of recurrent intra-abdominal cancer in patients with increased tumor markers and negative findings on conventional imaging studies.

METHODS

Seventy-three patients (30 men; age 61.1 ± 11.5 years) with intra-abdominal cancer (colorectal, n=32; ovarian, n=18; gastric, n=7; pancreatic, n=7; cervical, n=4; endometrial, n=3; duodenal, n=1; and small bowel, n=1) and increasing levels of tumor markers during follow-up and negative CT, MRI or both underwent 125 18F-FDG PET/CT examinations. The final diagnosis was confirmed by histopathological findings in 22 patients, clinical follow-up (median of 12 months) in 13 patients,and repeated imaging with 18F-FDG PET/CT examinations in 38 patients.

RESULTS

Of 73 cancer patients, 18F-FDG PET/CT identified recurrent disease in 52 patients and ruled out in 21 patients. 18F-FDG PET/CT scan was true positive (TP) in 49 patients, false positive in three patients, false negative in four patients, and true negative in 17 patients. In our study, the 18F-FDG-PET/CT scan had a sensitivity of 92.4%, a specificity of 85%, and an accuracy of 91%. Fourteen of 49 TP studies (28.5%) showed peritoneal implants only. Moreover, peritoneal implants were detected in additional nine of 49 TP studies (18.3%) presented with multiple lesions. Thus, half of the true-positive examination revealed peritoneal implants that CT or MRI had not depicted.

CONCLUSION

The results of this study indicate a high incidence of peritoneal implants revealed by 18F-FDG PET/CT in the diagnosis of recurrent intra-abdominal cancer in patients with increasing tumor markers and negative findings on conventional imaging studies.

Pretargeted immuno-PET of CEA-expressing intraperitoneal human colonic tumor xenografts: a new sensitive detection method

BACKGROUND

In this study, pretargeted immuno-positron-emission tomography [PET] with a bispecific monoclonal anti-carcinoembryonic antigen [CEA] (CEACAM5) × anti-hapten antibody (bispecific monoclonal antibody [bsmAb]) and a small (1.5 kD) peptide labeled with 68Ga was compared to fludeoxyglucose [18F-FDG]-PET for detecting intraperitoneal [i.p.] CEA-expressing human colonic tumor xenografts in nude mice.

METHODS

Two groups of female BALB/c nude mice were inoculated with LS174T human colonic tumor cells i.p. One group received 5 MBq 18F-FDG, and the other received intravenous injections of the bsmAb, followed 16 h later with 5 MBq of 68Ga-labeled peptide. One hour after the radiolabeled peptide or FDG was given, micro-PET/computed tomography images were acquired. Thereafter, the uptake of the 68Ga or 18F in dissected tissue was determined.

RESULTS

Within 1 h, high uptake of the 68Ga-labeled peptide in the tumor lesions (23.4 ± 7.2% ID/g) and low background activity levels were observed (e.g., tumor-to-intestine ratio, 58 ± 22). This resulted in a clear visualization of all intra-abdominal tumor lesions ≥ 10 μL and even some tumors as small as 5 μL (2 mm diameter). 18F-FDG efficiently localized in the tumors (8.7 ± 3.1% ID/g) but also showed physiological uptake in various normal tissues (e.g., tumor-to-intestine ratio, 3.9 ± 1.1).

CONCLUSIONS

Pretargeted immuno-PET with bsmAb and a 68Ga-labeled peptide could be a very sensitive imaging method for imaging colonic cancer, disclosing occult lesions.

Preoperative [F]FDG PET/CT predicts recurrence in patients with epithelial ovarian cancer

OBJECTIVE

To determine whether [(18)F]FDG uptake on PET/CT imaging before surgical staging has prognostic significance in patients with epithelial ovarian cancer (EOC).

METHODS

Patients with EOC were imaged with integrated PET/CT before surgical staging. Hypermetabolic lesions were measured as the standardized uptake value (SUV) in primary and metastatic tumors. SUV distribution was divided into two regions at the level of umbilicus, and the impact of the ratio between above and below umbilicus (SUV(location) ratio) on progression-free survival (PFS) was examined using Cox proportional hazards regression.

RESULTS

Between January 2004 and December 2009, 55 patients with EOC underwent preoperative PET/CT. The median duration of PFS was 11 months (range, 3 to 43 months), and twenty (36.4%) patients experienced recurrence. In univariate analysis, high SUV(location) ratio (p=0.002; hazard ratio [HR], 1.974; 95% confidence interval [CI], 1.286 to 3.031) was significantly associated with recurrence. Malignant mixed mullerian tumor compared with endometrioid histology was also shown to have significance. In multivariate analysis, high SUV(location) ratio (p=0.005; HR, 2.418; 95% CI, 1.1315 to 4.447) and histology (serous, mucinous, and malignant mixed mullerian tumor compared with endometrioid type) were significantly associated with recurrence. Patients were categorized into two groups according to SUV(location) ratio (<0.3934 vs. ≥0.3934), and the Kaplan-Meier survival graph showed a significant difference in PFS between the groups (p=0.0021; HR, 9.47, log-rank test).

CONCLUSION

SUV distribution showed a significant association with recurrence in patients with EOC, and may be a useful predictor of recurrence.