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

Cellularity of mucus is a prognostic variable in low-grade appendiceal mucinous neoplasms

For peritoneal metastases from a primary appendiceal mucinous neoplasm to exist, the thin wall of the appendix must perforate to allow mucus or mucus plus tumor cells to gain access to the peritoneal spaces. The proportion of specimens containing tumor cells within mucus as compared to mucus only outside the appendix may have prognostic significance. The histopathology of tumor masses was determined from the specimens resected at the cytoreductive surgery (CRS). The presence versus absence of tumor cells in mucus and the proportion of specimens with tumor cells was determined and correlated with the overall survival of these patients. In 418 patients with a complete cytoreduction for a low-grade appendiceal mucinous neoplasm (LAMN), the cellularity of all resected specimens was determined. The hazard ratio of overall survival of patients whose specimens had no cells as compared to specimens with cells in mucus by histology was 4.41 (1.61, 12.1) (p = 0.0039). If overall survival of patients with all specimens without tumor cells was compared to patients with specimens with 1-99 % tumor and compared to patients with 100 % of specimens with tumor cells, the hazard ratios were 4.3 (1.34, 13.8) (p = 0.0143) and 9.62 (2.93, 31.6) (p = 0.0002), respectively. The cellularity of mucus within the specimens removed by a complete CRS has strong prognostic implications in LAMN patients. LAMN with acellular specimens (LAMNa) as compared to LAMN with tumor cells in specimens (LAMNb) should be staged as different histologic subtypes of mucinous appendiceal neoplasms.

It Is What the Surgeon Does Not See That Kills the Patient

BACKGROUND

Patients with colon cancer may present at multiple different stages of the disease process. Many patients can be cured of colon cancer as a result of a simple surgical procedure usually performed by minimally invasive techniques. However, there are a variable number of patients, estimated at approximately 10%, who have a more advanced disease. If these patients are treated by the current conventional standard of care, the likelihood for treatment failure is extremely high.

METHODS

These are not patients with known disseminated disease but patients who are at high risk of recurrent disease unless special treatments are initiated preoperatively and intraoperatively. The identification of these patients is by (1) a high-quality CT scan, (2) tumor markers found preoperatively, (3) colonoscopic findings, and (4) symptoms.

RESULTS

Patients identified as being at high risk require special preoperative treatments which include neoadjuvant chemotherapy. Intraoperative chemotherapy with HIPEC should occur as part of the treatment if peritoneal metastases are documented by biopsy. In the operating room, a thorough exploration of all possible occult peritoneal spaces for metastatic disease needs to be performed. A modified cytoreductive surgical procedure along with a colon resection is performed in order to minimize sites of occult peritoneal metastases. This includes the greater omentum, ovaries, and tubes in postmenopausal women. Peritonectomy is used to create a shroud around the tumor so that all peritoneum that has been in direct contact with the tumor surface is resected and is used as a barrier against tumor cell dissemination in the process of colon cancer resection. If peritoneal metastases are visualized at any site, HIPEC should be included as part of the treatment package.

CONCLUSIONS

I am convinced that patients at high risk of recurrence will have an improved outcome with proper preoperative evaluation, preoperative neoadjuvant chemotherapy, and a revised intraoperative management strategy.

Selection Factors for Treatment and Stratification of Rare Abdominal or Pelvic Tumors with Peritoneal Metastases

To maximize the results of treatments for peritoneal metastases for rare abdominal or pelvic tumors, selection of patients with a possibility for long-term success is necessary. Because these malignancies are rare, data from which these selection factors can be extracted do not exist. In order to facilitate knowledgeable patient selection for treatment, the well established clinical and histopathologic features of the common malignancies treated for peritoneal metastases were reviewed. The potential application of selection factors for common diagnoses was explored in an attempt to provide selection factors for rare tumors. The histopathologic grade, the lymph node status, the Ki-67 proliferation index, prior surgical score (PSS), preoperative radiologic imaging, preoperative laparoscopic assessment, response to neoadjuvant chemotherapy, peritoneal cancer index (PCI), and completeness of cytoreduction score were all included in this search for relevant selection factors for a rare disease. To facilitate the use of selection factors from common peritoneal metastases diagnoses, these diseases were divided into four groups. Placement of the rare cause of peritoneal metastases into one of these four groups will allow knowledgeable selection for treatment. Rare diseases with a natural history resembling low-grade appendiceal neoplasms are in group 1, diseases resembling lymph node negative colorectal cancer are in group 2, diseases resembling lymph node positive colorectal peritoneal metastases in group 3, and diseases resembling gastric cancer in group 4.

Diagnostic and Therapeutic Pathway in Diffuse Malignant Peritoneal Mesothelioma

Diffuse malignant peritoneal mesothelioma (DMPM) is a rare form of mesothelioma that carries a very poor prognosis. The 5-year overall survival is about 20% (±5.9). Survival is optimal for patients suitable for cytoreductive surgery (CRS) with Hyperthermic Intraperitoneal Chemotherapy (HIPEC), with a median OS ranging from 34 to 92 months. However, selecting patients for surgery remains a complex task and requires a careful preoperative workup, rational analysis of prognostic profiles, and risk prediction models. Systemic chemotherapy could be offered: (1) in the adjuvant setting for high-risk patients; (2) for patients not eligible for CRS; and (3) for those with recurrent disease. It mainly includes the combination of Platin compound with Pemetrexed or immunotherapy. The biology of DMPM is still largely unknown. However, progress has been made on some fronts, such as telomere maintenance mechanisms, deregulation of apoptosis, tyrosine kinase pathways, and mutation of BRCA1-associated protein 1 (BAP1). Future perspectives should include translational research to improve our understanding of the disease biology to identify druggable targets. We should also clear the role of immune checkpoint inhibitors and investigate new locoregional technologies, such as pressurized intraperitoneal aerosol chemotherapy (PIPAC) or normothermic intraperitoneal chemotherapy (NIPEC).

Methylthioadenosine Phosphorylase and Breast Cancer 1 Protein-Associated Protein 1 as Biomarkers for the Peritoneal Mesothelioma

OBJECTIVES

Combination of Breast Cancer 1 protein-associated protein 1 (BAP1) and methylthioadenosine phosphorylase (MTAP) in the peritoneal mesothelioma (PeM) has yet to be explored. We aim to assess the diagnostic value of combined BAP1 and MTAP to distinguish biphasic mesothelioma (BM) from epithelioid mesothelioma (EM) with reactive stroma in peritoneum, as well as its prognostic value in PeM.

METHODS

This is a retrospective study from June 2014 to December 2021. This study included 18 cases of BM and 27 cases of EM with reactive stroma, excluded sarcomatoid, and EM without reactive stroma cases, and clinicopathological information was collected. The associations between MTAP and BAP1 levels and clinicopathological features or prognosis were analyzed. Clinical follow-up data were reviewed to correlate with pathological prognostic factors using Kaplan-Meier estimator and univariate/multivariate Cox proportional hazards regression models.

RESULTS

Loss/decrease of BAP1/MTAP was observed in 6 (33.3%) BM cases and 12 (44.4%) EM cases. In 5 (27.8%) cases, loss of or decreased BAP1/MTAP expression was observed in both EC and SC of BM. BAP1/MTAP loss/decrease was observed in 12 (44.4%) cases of only EC of EM but not in reactive stroma. Compared with histology alone, a combination of BAP1 and MTAP immunohistochemistry (IHC) in spindled PeM provides a more objective mean to distinguish BM from EM with reactive stroma. Loss/decrease of BAP1/MTAP was associated with peritoneal cancer index (PCI) score (P = 0.047) and completeness of cytoreduction (CC) score (P = 0.038). BM patients have worse overall survival (OS) than EM with reactive stroma (P = 0 .007).

CONCLUSIONS

Combination of BAP1/MTAP by IHC is helpful for differential diagnosis of peritoneal BM from EM with reactive stroma. Nevertheless, BAP1/MTAP may help to evaluate the biological behavior of PeM.

Differentiating malignant pleural mesothelioma and metastatic pleural disease based on a machine learning model with primary CT signs: A multicentre study

Rationale and Objectives

It is still a challenge to make confirming diagnosis of malignant pleural mesothelioma (MPM), especially differentiating from metastatic pleural disease (MPD). The aim of this study was to develop a model to distinguish MPM with MPD based on primary CT signs.

Materials and methods

We retrospectively recruited 150 MPM patients and 147 MPD patients from two centers and assigned them to training (115 MPM patients and 113 MPD patients) and testing (35 MPM patients and 34 MPD patients) cohorts. The images were analyzed for pleural thickening, hydrothorax, lymphadenopathy, thoracic volume and calcified pleural plaque (CPP). The selected clinical characteristics and primary CT signs comprised the model by multivariate logistic regression in the training cohort. Then the model was tested on the external testing cohort. ROC curve and F1 score were used to validate the capability of the model in both two cohorts.

Results

There were significant differences between two groups: (1) carcinoembryonic antigen (CEA); (2) nodular and mass pleural thickening; (3) the enhancement of pleura; (4) focal, diffuse and circumferential pleural thickening; (5) the thickest pleura; (6) thickening of diaphragmatic pleura; (7) multiple nodules and effusion of interlobar pleura; (8) hilar LN and ring enhancement of LN; (9) punctate and stipe CPP. The AUC and F1 score of the model were 0.970 and 0.857 in the training cohort, 0.955 and 0.818 in the testing cohort.

Conclusion

The model holds promise for use as a diagnostic tool to distinguish MPM from MPD.

Implications of peritoneal cancer index distribution on patients undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy

Objectives

Peritoneal cancer index (PCI) score is a common prognostication tool in peritoneal metastases (PM). We hypothesize that the distribution of PCI score and involvement of specific regions affects survival and morbidity outcomes.

Methods

Data was collected from a prospective database of patients who underwent CRS and HIPEC for PM at the National Cancer Centre Singapore. We evaluate the relationship between PCI, PCI distribution, and survival and morbidity outcomes.

Results

One hundred and fifty-two patients underwent CRS and HIPEC with a median PCI score of nine (range 0–31). Median overall survival (OS) and progression free survival (PFS) were 43 and 17 months, respectively. Region six (pelvis) was most commonly involved and had the highest frequency of heavy disease burden. Presence of PM in the lower abdomen, flanks, and small bowel were associated with poorer OS (p=0.01, 0.03, <0.001) and PFS (p=0.04, 0.02, <0.001). Involvement of porta hepatitis predicted poorer OS but not PFS (p=0.03). Involvement of the gastric antrum resulted in higher rates of postoperative complications.

Conclusions

The pattern of PCI distribution may be associated with varying survival and morbidity outcomes.

Challenging Diagnostic Process for a Malignant Peritoneal Mesothelioma Patient With Ascites and Pleural Effusion: A Case Report and Review of the Literature

Malignant peritoneal mesothelioma (MPM) is a sporadic and fatal disease of the peritoneal lining. Its diagnosis has been known to be challenging, time-consuming, and money-consuming. In this paper, we report an MPM case of a 58-year-old man with severe abdominal distension. After he had received all kinds of auxiliary examination, including computed tomography scans of the chest and whole abdomen, examinations of peripheral and pleural fluid, positron emission tomography, and twice fine-needle peritoneal biopsies, his disease still could not be confirmed. Eventually, the patient was diagnosed with MPM through laparoscopic biopsy and IHC. From this case, we concluded that clinicians can gradually discover and diagnose the disease through 1) high platelet and CA125 levels and CT imaging results, 2) cytologic examinations of ascites and pleural fluid, 3) peritoneal biopsies (fine-needle biopsy, laparoscopy biopsy), and 4) histopathological examinations and immunohistochemistry findings. The diagnostic process involving this patient can be an example to demonstrate the effectiveness of various auxiliary examination methods in MPM diagnosis.

Use of an antagonist of HMGB1 in mice affected by malignant mesothelioma: a preliminary ultrasound and optical imaging study

Background

Malignant mesothelioma (MM) is an aggressive tumor, with a poor prognosis, usually unresectable due to late diagnosis, mainly treated with chemotherapy. BoxA, a truncated form of “high mobility group box 1” (HMGB1), acting as an HMGB1 antagonist, might exert a defensive action against MM. We investigated the potential of BoxA for MM treatment using experimental 40-MHz ultrasound and optical imaging (OI) in a murine model.

Methods

Murine MM cells infected with a lentiviral vector expressing the luciferase gene were injected into the peritoneum of 14 BALB/c mice (7 × 10⁴ AB1-B/c-LUC cells). These mice were randomized to treatment with BoxA (n = 7) or phosphate-buffered saline (controls, n = 7). The experiment was repeated with 40 mice divided into two groups (n = 20 + 20) and treated as above to confirm the result and achieve greater statistical power. Tumor presence was investigated by experimental ultrasound and OI; suspected peritoneal masses underwent histopathology and immunohistochemistry examination.

Results

In the first experiment, none of the 7 controls survived beyond day 27, whereas 4/7 BoxA-treated mice (57.1%) survived up to day 70. In the second experiment, 6/20 controls (30.0%) and 16/20 BoxA-treated mice (80.0%) were still alive at day 34 (p = 0.004). In both experiments, histology confirmed the malignant nature of masses detected using experimental ultrasound and OI.

Conclusion

In our preclinical experience on a murine model, BoxA seems to exert a protective role toward MM. Both experimental ultrasound and OI proved to be reliable techniques for detecting MM peritoneal masses.

Revised prognostic indicators for treatment of lymph node positive colorectal peritoneal metastases

BACKGROUND

Peritoneal metastases from colon and rectal cancer presents a new target for a regional approach to treatment. Proper patient selection requires an understanding of the natural history of the disease progression.

METHODS

Data from colorectal cancer patients treated for peritoneal metastases by cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy and early postoperative intraperitoneal chemotherapy and the records from the primary colon or rectal cancer surgery were analyzed to assess their impact on survival. Data regarding the anatomic sites of colorectal peritoneal metastases was gathered at the time of a complete CRS.

RESULTS

A cohort of 73 patients with peritoneal metastases and lymph node metastases but no liver metastases provided the information. All patients had a complete cytoreduction. Left-sided primary cancer and a complete or near complete response to neoadjuvant chemotherapy (NAC) indicated improved survival. Tumor progression within the abdominal incision, carcinoembryonic antigen (CEA) >10, peritoneal cancer index >9 and peritoneal metastases present in the abdominopelvic regions 6 and 11 carried an especially guarded prognosis.

CONCLUSIONS

Reduced survival occurred with a right-sided or rectal primary cancer, a CEA >10, tumor cell entrapment, and involvement of abdominopelvic regions 6 and 11. Effective NAC showed a favorable outcome.

Cytoreductive Surgery Plus HIPEC With and Without NIPEC for Malignant Peritoneal Mesothelioma: A Propensity-Matched Analysis

BACKGROUND

Malignant peritoneal mesothelioma is a rare and often fatal disease. Dissemination is confined to the abdominal and pelvic peritoneal spaces in a great majority of patients.

METHODS

Standardized cytoreductive surgery and perioperative chemotherapy was used in all patients. Long-term normothermic intraperitoneal chemotherapy (NIPEC) was added to the treatment of our most recent group of patients. Survival with and without NIPEC was compared using a propensity-matched analysis.

RESULTS

In a uniform group of 74 patients, the clinical- and treatment-related features that had an impact on survival were age (hazard ratio [HR] 1.99, 95% confidence interval [CI] 0.929-4.238, p = 0.0766), completeness of cytoreduction (HR 2.356, 95% CI 1.113-4.989, p = 0.0251), and treatments administered (HR 3.497, 95% CI 1.199-10.20, p = 0.0219). In the Cox proportional hazards multivariant model, sex and age were borderline significant. Treatments administered were significant (HR 3.549, 95% CI 1.157-10.888, p = 0.0268). Using five features to match 29 patients in the control group (no NIPEC) to 29 patients in the experimental group (with NIPEC), the propensity-matched survival was significantly different (p = 0.0263).

CONCLUSIONS

The addition of NIPEC was associated with long-term survival in this cohort of patients. A multi-institutional randomized trial may be the next step.