Determining a minimum data set for reporting clinical and radiologic data for pseudomyxoma peritonei.

Objectives: Pseudomyxoma peritonei (PMP) is a rare cancer currently affecting over 11,736 patients across Europe. Since PMP is so uncommon, collaboration between scientific centers is key to discovering the mechanisms behind the disease, efficient treatments, and targets pointing to a cure. To date, no consensus has been reached on the minimum data that should be collected during PMP research studies. This issue has become more important as biobanking becomes the norm. This paper begins the discussion around a minimum data set that should be collected by researchers through a review of available clinical trial reports in order to facilitate collaborative efforts within the PMP research community. Content: A review of articles from PubMed, CenterWatch, ClinicalTrials.gov and MedRxiv was undertaken, and clinical trials reporting PMP results selected. Summary: There is a core set of data that researchers report, including age and sex, overall survival, peritoneal cancer index (PCI) score, and completeness of cytoreduction, but after this, reports become variable. Outlook: Since PMP is a rare disease, it is important that reports include as large of a number of standardised data points as possible. Our research indicates that there is still much ground to cover before this becomes a reality.

Communicating imaging findings in peritoneal mesothelioma: the impact of 'PAUSE' on surgical decision-making.

The peritoneal cavity is the second commonest site of mesothelioma after the pleural cavity. There are five histological types of peritoneal mesothelioma with variable symptomatology, clinical presentation and prognosis. Cystic mesothelioma is a borderline malignant neoplasm with a favourable prognosis, well-differentiated papillary mesothelioma is generally a low-grade malignancy, and all other varieties such as epithelioid, sarcomatoid and biphasic mesothelioma are highly malignant types of peritoneal mesothelioma with poor prognosis. Malignant peritoneal mesothelioma was considered inevitably fatal prior to the introduction of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) in selected cases where long-term survival and cure could be achieved. However, the survival benefits following CRS and HIPEC mainly depend on completeness of cytoreduction, which come at the cost of high morbidity and potential mortality. Using the acronym 'PAUSE', we aimed at describing the key imaging findings that impact surgical decision-making in patients with peritoneal mesothelioma. PAUSE stands for peritoneal cancer index, ascites and abdominal wall disease, unfavourable sites of involvement, small bowel and mesenteric disease and extraperitoneal disease. Reporting components of 'PAUSE' is crucial for patient selection. Despite limitations of CT in accurately depicting the volume of disease, describing findings in terms of PAUSE plays an important role in excluding patients who might not benefit from CRS and HIPEC.

Additional Value of Dynamic Contrast-enhanced Sequences in Multiparametric Prostate Magnetic Resonance Imaging: Data from the PROMIS Study.

BACKGROUND: Multiparametric magnetic resonance imaging (MP-MRI) is established in the diagnosis of prostate cancer, but the need for enhanced sequences has recently been questioned. OBJECTIVE: To assess whether dynamic contrast-enhanced imaging (DCE) improves accuracy over T2 and diffusion sequences. DESIGN, SETTING, AND PARTICIPANTS: PROMIS was a multicentre, multireader trial, with, in this part, 497 biopsy-naïve men undergoing standardised 1.5T MP-MRI using T2, diffusion, and DCE, followed by a detailed transperineal prostate mapping (TPM) biopsy at 5 mm intervals. Likert scores of 1-5 for the presence of a significant tumour were assigned in strict sequence, for (1) T2 + diffusion and then (2) T2 + diffusion + dynamic contrast-enhanced images. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: For the primary analysis, the primary PROMIS outcome measure (Gleason score ≥4 + 3 or ≥6 mm maximum cancer length) on TPM was used, and an MRI score of ≥3 was considered positive. RESULTS AND LIMITATIONS: Sensitivity without and with DCE was 94% and 95%, specificity 37% and 38%, positive predictive value 51% and 51%, and negative predictive value 90% and 91%, respectively (p > 0.05 in each case). The number of patients avoiding biopsy (scoring 1-2) was similar (123/497 vs 121/497, p = 0.8). The number of equivocal scores (3/5) was slightly higher without DCE (32% vs 28% p = 0.031). The proportion of MRI equivocal (3/5) and positive (4-5) cases showing significant tumours were similar (23% and 71% vs 20% and 69%). No cases of dominant Gleason 4 or higher were missed with DCE, compared with a single case with T2 + diffusion-weighted imaging. No attempt was made to correlate lesion location on MRI and histology, which may be considered a limitation. Radiologists were aware of the patient's prostate-specific antigen. CONCLUSIONS: Contrast adds little when MP-MRI is used to exclude significant prostate cancer. PATIENT SUMMARY: An intravenous injection of contrast may not be necessary when magnetic resonance imaging is used as a test to rule out significant tumours in the prostate.

Single centre guidelines for radiological follow-up based on 775 patients treated by cytoreductive surgery and HIPEC for appendiceal pseudomyxoma peritonei.

AIM: Pseudomyxoma peritonei (PMP) is an uncommon malignancy, generally originating from a ruptured epithelial tumour of the appendix. Despite successful cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC), some patients recur. Currently there are no guidelines on the methods, frequency and intensity of follow-up. METHODS: Between 1994 and 2016, 1070 patients underwent surgery for a perforated epithelial tumour of the appendix, predominantly with PMP. Overall (OS) and Disease Free Survival (DFS) were documented by annual CT scanning and evaluated according to the Kaplan-Meier method. The influence of histological differentiation was investigated. RESULTS: Overall, 775/1070 (72%) had complete cytoreductive surgery (CCRS) and HIPEC. Histological classification was low grade PMP in 615 (79.4%), high grade PMP in 134 (17.3%) and adenocarcinoma in 26 (3.4%). DFS and OS were significantly worse for high grade disease, with the steepest decline for both in the first three years. DFS curves, for low as well as high grade PMP, levelled off at year 6 at approximately 60% and 20% respectively. Thereafter there were few recurrences in either group. CONCLUSION: Annual CT of the abdomen and pelvis in the first six years appears to be adequate follow-up for low grade PMP. In high grade PMP, additional imaging of the chest and more frequent surveillance, during the first three years postoperatively, may detect recurrent disease earlier. From year 6 on, reduced frequency of follow-up is proposed, independent of the histology. This long-term follow-up in a large number of patients gives insight into tumour behavior after CCRS and HIPEC for PMP and guides intensity of surveillance.

Radiological predictors of complete cytoreduction in 59 patients with peritoneal mesothelioma treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy at a UK referral centre.

OBJECTIVE: To assess the imaging features of peritoneal mesothelioma and identify key anatomical sites that aid patient selection for complete cytoreduction. METHODS: Pre-operative imaging of 59 (32 males, 27 females) patients who underwent cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC) for histologically proven peritoneal mesothelioma [36 malignant peritoneal mesothelioma, 23 cystic mesothelioma were reviewed. Imaging findings were correlated with surgical outcome. Best imaging predictors of complete cytoreduction, n = 22 and major tumour debulking, n = 12 were assessed. RESULTS: Most patients (88.9%) had diffuse peritoneal disease with mean radiological peritoneal cancer index of 18 ± 12 (range 2-39). Disease in the lesser omentum (n = 10), porta hepatis (n = 8), perigastric area (n = 5), mesentery (n = 25), small bowel (n = 17), hydronephrosis (n = 1), concurrent pleural disease (n = 2), lymph nodes (n = 1) and abdominal wall disease (n = 4) was considered unfavourable. While 78.9% of patients who underwent complete cytoreduction had no disease at unfavourable sites, 75% of those who underwent MTD did have disease at these sites. There was significant difference in the radiological peritoneal cancer index, severity of upper abdominal disease, small bowel and mesenteric involvement between patients who underwent complete cytoreduction and MTD for malignant peritoneal mesothelioma. Complete cytoreduction was not achieved in the presence of a rind of soft tissue around the small bowel (p = 0.016) and was unlikely in the presence of large volume upper abdominal disease (p = 0.06). CONCLUSION: Involvement of key anatomical sites such as small bowel serosa and large volume upper abdominal disease reduced the likelihood of achieving complete cytoreduction in patients with malignant peritoneal mesothelioma. Advances in knowledge: Demonstration of small bowel disease and large volume upper abdominal disease on imaging in patients with malignant peritoneal mesothelioma can be used to identify patients who may not benefit from cytoreductive surgery.