Diffuse malignant mesothelioma of the peritoneum: a clinicopathological study of 35 patients treated locoregionally at a single institution

Long-Term Survival in Patients Treated with Cytoreduction and Heated Intraperitoneal Chemotherapy for Peritoneal Mesothelioma at a Single High-Volume Center

BACKGROUND

Malignant peritoneal mesothelioma (MPM) is a rare diagnosis with a dismal prognosis if untreated. Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is shown to significantly improve survival. Our institution is uniquely positioned to report long-term outcomes in MPM with CRS-HIPEC, due to our robust peritoneal surface disease program existing over the past three decades.

METHODS

Our prospectively maintained, single-institution database of CRS-HIPEC cases was reviewed, identifying 111 consecutive patients with MPM over 28 years (1993-2021). Prognostic, operative, and pathologic factors were reviewed. Overall survival (OS) and conditional survival (CS) analyses were performed.

RESULTS

The average age was 55.1 years; 58.6% of patients were male; 17 of 111 patients (15.3%) had a second CRS-HIPEC. At first CRS-HIPEC, the average PCI score was 18.7, and the perfusate drugs were platinum-based (72.1%) and mitomycin C (27.9%). The resection status at first CRS-HIPEC was R2a (46.4%), followed by R0-1 (29.1%), and R2b-c (24.5%). Median OS was 3.3 years for the entire cohort, with 75th and 25th percentiles at 10.7 months and 10.6 years. Median CS was improved if patients survived to the 1-year postoperative mark (4.9 years, p < 0.01) and trended toward further improvement with each passing year. If 3-year postoperative survival was achieved, the median CS improved to 6.1 years.

CONCLUSIONS

This represents one of the largest and lengthiest, single-center, longitudinal, case series of peritoneal mesothelioma treated with CRS-HIPEC. The OS suggests efficacy for CRS-HIPEC for MPM. Long-term survival improves significantly after patients achieve the 1-year, postoperative mark.

Malignant peritoneal mesothelioma: correlation between CT imaging features and histologic subtypes

PURPOSE

To identify correlation between CT imaging features and histologic subtypes of Malignant Peritoneal Mesothelioma (MPM).

METHODS

This was a retrospective single-center study of 51 consecutive patients with the diagnosis of Malignant Peritoneal Mesothelioma (MPM). The tumors were classified into pure epithelioid type and those with sarcomatoid component (pure sarcomatoid and biphasic type). Imaging features of these subtypes were compared for extent and type of peritoneal thickening, omental thickening, abdominal visceral infiltration, abdominal wall infiltration, and loco-regional and distant metastases. Fisher's Exact test was used to correlate the association of imaging features with histology types followed by multivariate analysis using logistic regression test.

RESULTS

32 males and 19 females with a median age of 63 years (range 35-86 years) were included in the study. 41/51 (80%) were epithelioid histology type and 10/51 (20%) had sarcomatoid component (3 pure sarcomatoid type, 7 biphasic type). Abdominal visceral infiltration was seen more commonly in cases of MPM with sarcomatoid component (p = 0.001). Sarcomatoid type also had a frequent association with metastases (p = 0.001) and discrete masses (p = 0.01). Epithelioid type was commonly associated with ascites (p = 0.04). On multivariate analysis, most significant correlation was identified between the sarcomatoid type and imaging features of metastases (p = 0.001) and visceral infiltration (p = 0.019).

CONCLUSION

Sarcomatoid type of MPM showed significant correlation with more aggressive imaging features of metastases and visceral infiltration as compared to epithelioid type.

Combined grade and nuclear grade are prognosis predictors of epithelioid malignant peritoneal mesothelioma: a multi-institutional retrospective study

Epithelioid mesothelioma is the most prevalent subtype of diffuse malignant peritoneal mesothelioma. A recently described nuclear-grading system predicted survival in patients with epithelioid malignant pleural mesothelioma. The present study was undertaken to validate this grading system in epithelioid malignant peritoneal mesothelioma (EMPM) and to compare to combined grade, including nuclear atypia, mitotic count, and tumor necrosis. Cases of EMPM, from 1995 to 2018, were analyzed from 7 French institutions from RENAPE network. Solid growth, tumor necrosis, nuclear atypia, and mitotic count were evaluated by at least 3 pathologists from the RENAPATH group. The predictions in terms of OS and PFS of nuclear grade and combined grade were analyzed. Nuclear grade was computed combining nuclear atypia score and mitotic count into a grade of I-III. Another system combining nuclear atypia score, mitotic score, and tumor necrosis was evaluated and defined as a combined grade I-III. A total of 138 cases were identified. The median follow-up was 38.9 months (range: 1.1-196.6). Nuclear and combined grades III were independently associated with a shorter OS (p < 0.05), and a shorter PFS (p < 0.05). Patients with combined grade I tumors had the best overall and progression-free survivals, in comparison to nuclear grade I. In this large multicentric study, combined grade and nuclear grade were the best independent predictors of OS and PFS in EMPM. These systems should be easily described by pathologists involved into the management of malignant peritoneal mesothelioma, because of their potential therapeutic implications.

Malignant peritoneal mesothelioma: prognostic significance of clinical and pathologic parameters and validation of a nuclear-grading system in a multi-institutional series of 225 cases

Malignant peritoneal mesothelioma historically carried a grim prognosis, but outcomes have improved substantially in recent decades. The prognostic significance of clinical, morphologic, and immunophenotypic features remains ill-defined. This multi-institutional cohort comprises 225 malignant peritoneal mesotheliomas, which were assessed for 21 clinical, morphologic, and immunohistochemical parameters. For epithelioid mesotheliomas, combining nuclear pleomorphism and mitotic index yielded a composite nuclear grade, using a previously standardized grading system. Correlation of clinical, morphologic, and immunohistochemical parameters with overall and disease-free survival was examined by univariate and multivariate analyses. On univariate analysis, longer overall survival was significantly associated with diagnosis after 2000 (P = 0.0001), age <60 years (P = 0.0001), ECOG performance status 0 or 1 (P = 0.01), absence of radiographic lymph-node metastasis (P = 0.04), cytoreduction surgery (P < 0.0001), hyperthermic intraperitoneal chemotherapy (P = 0.0001), peritoneal carcinomatosis index <27 (P = 0.01), absence of necrosis (P = 0.007), and epithelioid histotype (P < 0.0001). Among epithelioid malignant mesotheliomas only, longer overall survival was further associated with female sex (P = 0.03), tubulopapillary architecture (P = 0.005), low nuclear pleomorphism (P < 0.0001), low mitotic index (P = 0.0007), and low composite nuclear grade (P < 0.0001). On multivariate analyses, the low composite nuclear grade was independently associated with longer overall and disease-free survival (P < 0.0001). Our data further clarify the interactions of clinical and pathologic features in peritoneal mesothelioma prognosis and validate the prognostic significance of a standardized nuclear-grading system in epithelioid malignant mesothelioma of the peritoneum.

Update on the management of malignant peritoneal mesothelioma

Malignant peritoneal mesothelioma (MPM) is a rare disease whose natural history is confined to the peritoneal space. Systemic chemotherapy has little impact on survival of patients with MPM. A surgical procedure with a goal of resection of all visible evidence of disease, called cytoreductive surgery (CRS) has been utilized in MPM patients. Also, regional chemotherapy with hyperthermic intraperitoneal chemotherapy (HIPEC) and normothermic intraperitoneal chemotherapy long-term (NIPEC-LT) have been effectively utilized in MPM patients. In the absence of CRS and HIPEC the median survival of MPM patients is approximately 1 year. The aggressive surgical approach plus regional chemotherapy has increased the median survival to more than 5 years. With NIPEC-LT added on, 70% 5-year survival has been reported. Knowledgeable patient selection for treatment is mandatory. The use of CRS, HIPEC and NIPEC-LT has greatly benefited patients with MPM. Global application of these treatments is indicated.

Management of Malignant Peritoneal Mesothelioma Using Cytoreductive Surgery and Perioperative Chemotherapy

Malignant peritoneal mesothelioma is a rare disease, with approximately 800 new patients per year in the United States. Its natural history is defined by progression restricted to the peritoneal space. In the past, patients with this disease had a limited lifespan of approximately 1 year. Numerous single-institution studies as well as a systematic review have reported median survival of 3 to 5 years with a combination of cytoreductive surgery and hyperthermic perioperative chemotherapy. These markedly improved survival statistics were achieved in experienced centers with 1% mortality and 20% morbidity rates. Data have shown that knowledgeable patient selection is required to prevent patients unlikely to benefit from undergoing these interventions. The conclusion is that patients with peritoneal mesothelioma can experience long-term progression-free survival or significant palliation with cytoreductive surgery plus hyperthermic perioperative chemotherapy. This management plan should be considered the standard of care for properly selected patients with malignant peritoneal mesothelioma at experienced centers around the world.

Long-term regional chemotherapy for patients with epithelial malignant peritoneal mesothelioma results in improved survival

PURPOSE

Malignant peritoneal mesothelioma (MPM) is a rare disease with about 300 new cases per year in the USA. Its natural history is described as local progression within the peritoneal space in the absence of liver metastases or systemic disease.

METHODS

Cytoreductive surgery (CRS) is a series of peritonectomy procedures and visceral resections with a goal of complete removal of all visible disease from the abdomen and pelvis. Over 20 years, three protocols investigating increasing efficacy of additional chemotherapy treatments added to CRS have been initiated. Initially, hyperthermic perioperative chemotherapy (HIPEC) with doxorubicin and cisplatin was used in the operating room. Then, early postoperative intraperitoneal chemotherapy (EPIC) with paclitaxel was added for the first 5 days after CRS. The third protocol employed HIPEC, then EPIC, and then long-term intraperitoneal (IP) paclitaxel or IP pemetrexed plus intravenous (IV) cisplatin as a adjuvant normothermic intraperitoneal chemotherapy (NIPEC).

RESULT

The 5-year survival of 42 patients treated with CRS and HIPEC was 44%, for 58 patients treated with EPIC and HIPEC was 52% and 29 patients who received HIPEC, EPIC, and NIPEC was 75% (p = 0.0374). Prognostic variables of age, gender, treatment administered, peritoneal cancer index (PCI) and completeness of cytoreduction were significant by univariate analysis and treatments administered and completeness of cytoreduction significant by multivariate analysis.

CONCLUSIONS

Long-term regional chemotherapy was associated with improved survival in patients with MPM. In this rare disease, additional phase 2 investigations are suggested.

Diagnostic immunohistochemistry through Rosai-coloured glasses

Over the past three decades, Immunohistochemistry has materially changed the practice of diagnostic surgical pathology. Foundational observations in this field were critical to a reasoned assessment of both the risks and opportunities that immunohistochemistry afforded the surgical pathologist, and our current practice draws heavily on those early assessments. As we collectively look to and acknowledge those who recognized the value of this technique and who helped guide its development as a companion to (not a replacement for) histomorphologic evaluation, we are drawn to those whose mastery of detail and ability to draw common patterns from seemingly unrelated phenomena helped define the diagnostic power of immunohistochemistry. The focus of this review is on one individual, Dr. Juan Rosai, whose contributions transcend the simple linkage of molecular observations to morphology, recognizing novel patterns in both form and color (the latter often the lovely shades of diaminobenzidine), seemingly viewing our diagnostic world at times through an entirely different lens. By looking at Dr. Rosai's early work in this field, reviewing a selection of his seminal observations, particularly in the Immunohistochemistry of thyroid and thymic neoplasia, revisiting how his special insight is often guided by the work of the early masters of morphology, and how his mentorship of others has helped shaped academic surgical pathology practice, perhaps we can get a glimpse through that lens.

Clinical significance of serum CA125 in diffuse malignant mesothelioma

Background

Malignant mesothelioma (MM) is a rare and fatal neoplasm. For diffuse malignant mesothelioma (DMM) patients that were not suitable for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy, systemic chemotherapy is the main treatment. There are no convenient tumor markers to predict the efficacy of treatment and disease progression. This study aimed to evaluate serum CA125 level as a biochemical marker of response to therapy and prognosis in patients with DMM.

Methods

A retrospective study was performed in a single medical institution from April 2008 to April 2014. Overall survival (OS) and prognostic factors were assessed.

Results

Forty-one patients were included with a median age of 53 years. The median OS of all patients was 10 months. Patients with baseline CA125 > 280 U/ml had worse OS compared with the patients that baseline CA125 ≤ 280 U/ml. Baseline level of CA125, stage of disease, primary tumor location and systemic chemotherapy were independent prognostic factors associated with OS. In patients who received systemic chemotherapy, the decline in serum CA125 was associated with favorable OS and objective response according to modified Response Evaluation Criteria in Solid Tumors criteria.

Conclusions

The baseline level of serum CA125, accompanied with stage of disease, primary tumor location and systemic chemotherapy, could be regarded as independent prognostic factors for DMM patients. Otherwise, the change in serum CA125 can predict OS and response to systemic chemotherapy.

The Role of Ki-67 and Pre-cytoreduction Parameters in Selecting Diffuse Malignant Peritoneal Mesothelioma (DMPM) Patients for Cytoreductive Surgery (CRS) and Hyperthermic Intraperitoneal Chemotherapy (HIPEC)

BACKGROUND

We conducted a prognostic analysis of preoperative parameters and Ki-67 determination to develop selection criteria for cytoreductive surgery (CRS) and HIPEC in patients with diffuse malignant peritoneal mesothelioma (DMPM).

METHODS

DMPM patients treated with CRS and HIPEC at NCI of Milan participated in this study. Multivariate analysis was conducted using Cox proportional hazard model and conditional inference tree method to select independent predictors of overall survival (OS) from the followings pre-cytoreduction parameters: age, sex, ECOG performance status, Charlson comorbidity index, previous systemic chemotherapy, CA-125, histological subtype (epithelioid vs. biphasic/sarcomatoid), Ki-67 (determined with immunohistochemistry), and peritoneal cancer index (PCI).

RESULTS

A total of 117 patients (male/female: 67/50) with median age of 60.5 (range 22-75) years were included. Eighty-three patients had ECOG performance status = 0, median Charlson comorbidity index was 4 (range 2-9), and 102 cases had epithelioid subtype. Median Ki-67 was 5 % (range 1-60). Ninety-four (80.3 %) cases were optimally cytoreduced. The Cox analysis identified Ki-67, PCI, and histological subtype as independent prognosticators of OS. Conditional inference tree method identified three prognostic subsets: (I) Ki-67 ≤ 9 %; (II) Ki-67 > 9 % and PCI ≤ 17; and (III) Ki-67 > 9 % and PCI > 17. The median OS for subsets I, II, and III were, 86.6, 63.2, and 10.3 months, respectively.

CONCLUSIONS

Ki-67 is a powerful prognosticator that allows, along with PCI, and histological subtype, a good prediction of OS in patients with DMPM. Patients with Ki-67 > 9 % and PCI > 17 are unlikely to benefit from the procedure and should be considered for other treatment protocols.

Treating peritoneal mesothelioma with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy. A case series and review of the literature

BACKGROUND

Encouraging results on survival of patients with malignant peritoneal mesothelioma have been shown with the use of cytoreductive surgery and perioperative intraperitoneal chemotherapy. This study explores the impact of aggressive surgical treatment on overall survival of peritoneal mesothelioma.

METHODS

This is a retrospective analysis of prospectively collected clinical data of all patients with diagnosis of malignant peritoneal mesothelioma treated in a designated referral centre in Greece. All patients were offered cytoreductive surgery and intraperitoneal chemotherapy. Patient's characteristics, operative reports, pathology reports, and discharge summaries were stored in an electronic database and later reviewed and analysed.

RESULTS

Cytoreduction for peritoneal mesothelioma was performed on 20 patients (15 men and 5 women) with a mean age of 59.4 years (SD 16.1). Mean peritoneal cancer index was 16.1 (SD 10.4) and the median completeness of cytoreduction score was 2 (range 1-2). Mean overall survival was 46.8 months (SE 4.03) with a mean of 21.4 and median of 18 months of follow-up. Disease-specific survival was 100% for the observed period. Univariate analysis showed the completeness of cytoreduction as the only possible predictor of survival. A median of 10 (range 4-14) peritonectomy procedures were performed per patient. Median hospital stay was 14 (range 10-57 days). Grade III and IV complications occurred post-operatively in 5 patients (25%). Two patients died in the post-operative period of pulmonary embolism and myocardial infarction.

CONCLUSION

Cytoreductive surgery with HIPEC has proved the most effective treatment even when taking account of the cost of significant morbidity.

Diffuse mesothelioma of the peritoneum: correlation between histological and clinical parameters and survival in 73 patients

There are few studies addressing survival of diffuse peritoneal mesotheliomas (DPM).In this study, survival data were obtained retrospectively from 73 patients treated with intended cytoreductive surgery for DPM, with a mean follow-up of 42 months. Mesotheliomas were classified as well differentiated papillary (WDPM, n = 2), multicystic (MCM, n = 4), and epithelioid mesotheliomas were subclassified as tubulopapillary (TPM, n = 27), solid/deciduoid (S/DM, n = 34), and or biphasic mesothelioma (BPM, n = 6). Invasion was characterised as absent (grade 0), into stroma (grade 1), into fat (grade 2), and into adjacent structures (grade 3). Peritoneal cancer index (PCI) and completeness of cytoreduction (CCR) were assessed surgically.There were no deaths in the WDPM, MCM, and epithelioid DPM with ≤ grade 1 invasion. There was a stepwise decrease in overall survival from invasive TPM, S/DM, and BPM (p < 0.0001). By univariate analysis, advanced age (p = 0.01), incomplete CCR (p < 0.001), PCI (p = 0.004), mitotic count (p < 0.001), nuclear grade (p < 0.0001), stromal inflammation (p = 0.013), depth of invasion (p < 0.0001), necrosis (p = 0.002), and sarcomatoid growth (p < 0.0001) were associated with decreased overall survival. By multivariate analysis, only sarcomatoid growth (p = 0.0006), depth of invasion (p = 0.02), elevated CCR (CCR 2-3) (p = 0.02), and presence of inflammatory stroma (p = 0.04) were significant variables associated with decreased overall survival.DPM form a spectrum of indolent to highly aggressive tumours. Solid epithelioid/deciduoid tumours have a prognosis intermediate between biphasic mesotheliomas and invasive TPM. The presence and degree of invasion, sarcomatoid features, and inflammatory stroma are poor prognostic indicators.

Repeat cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for recurrent diffuse malignant peritoneal mesothelioma

INTRODUCTION

Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) has shown to improve survival outcomes for patients with diffuse malignant peritoneal mesothelioma (DMPM).

PATIENTS AND METHODS

This is a retrospective study of prospectively collected data of 44 consecutive patients with DMPM who underwent CRS and HIPEC by the same surgical team at St George Hospital in Sydney, Australia. A total of 58 operations were performed. Clinical data were divided according to the number of operation and HIPEC the patient had undergone (Group 1 = initial CRS and HIPEC; Group 2 = 2nd CRS and HIPEC; Group 3 included 3rd CRS and HIPEC; Group 4 = 4th CRS and HIPEC). A significant difference was defined as p < 0.05.

RESULTS

There were no significant differences in mortality and morbidity results among the four groups. The median survival for those who only had one operation was 22 months (95% confidence interval (CI) = 0-47.2), whereas the median survival for those who had a second operation was 62 months (95% CI = 22.9-101.1). However, such a difference did not translate into a statistical significance (p = 0.141).

CONCLUSION

We report an encouraging median survival of 62 months in patients who had recurrence of disease and had repeat CRS and HIPEC with similar morbidity and mortality with the initial operation. Due to the learning curve of this technique, patients with recurrent mesothelioma should be referred to specialised tertiary care centres for evaluation. Selected patients may experience prolonged survival after repeat CRS and HIPEC.

Immunohistochemical Evaluation of Minichromosome Maintenance Protein 7 (MCM7), Topoisomerase IIα, and Ki-67 in Diffuse Malignant Peritoneal Mesothelioma Patients Using Tissue Microarray

PURPOSE

Immunohistochemistry and tissue microarray (TMA) were used to perform a prognostic analysis of markers related to cell proliferation in diffuse malignant peritoneal mesothelioma (DMPM).

METHODS

Clinicopathologic data were extracted from a prospectively collected database containing cases of peritoneal mesothelioma treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in the National Cancer Institute of Milan from 1995 to 2013. Eighty-one DMPM patients were recruited and their tissue samples were used to construct TMAs. We evaluated the immunoexpressions of markers related to cell proliferation-topoisomerase IIα, minichromosome maintenance protein 7 (MCM7), and Ki-67-and then conducted a multivariate Cox model to identify the predictors of overall survival (OS) and progression-free survival (PFS) among the following parameters: age, sex, Eastern Cooperative Oncology Group (ECOG) performance status, baseline serum albumin, Charlson Comorbidity Index, previous systemic chemotherapy, histological subtype (epithelioid vs. biphasic/sarcomatoid), peritoneal cancer index, completeness of cytoreduction (CC), and proliferative biological markers.

RESULTS

The rates of high/intermediate immunoreactivity were 95 % for topoisomerase IIα and 90 % for MCM7, and the median Ki-67 labeling index was 5 %. The independent predictors of OS were baseline serum albumin >3.5 g/dl, CC, and Ki-67 >5 %, whereas those for PFS were an ECOG performance status of 0, baseline serum albumin >3.5 g/dl, Charlson Comorbidity Index >3, previous systemic chemotherapy, morbidity G3-5, and Ki-67 >5 %. The remaining biological markers were not associated with outcome.

CONCLUSIONS

Ki-67 was found to be a new powerful determinant of outcome. Patients with a Ki-67 labeling index >5 % carry a very poor prognosis and do not benefit from the combined procedure. Further studies should be conducted to confirm the present data.

Advances in the management of peritoneal mesothelioma

Malignant peritoneal mesothelioma (PM) is an infrequent disease which has historically been associated with a poor prognosis. Given its long latency period and non-specific symptomatology, a diagnosis of PM can be suggested by occupational exposure history, but ultimately relies heavily on imaging and diagnostic biopsy. Early treatment options including palliative operative debulking, intraperitoneal chemotherapy, and systemic chemotherapy have marginally improved the natural course of the disease with median survival being approximately one year. The advent of cytoreduction (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has dramatically improved survival outcomes with wide median survival estimates between 2.5 to 9 years; these studies however remain largely heterogeneous, with differing study populations, tumor biology, and specific treatment regimens. More recent investigations have explored extent of cytoreduction, repeated operative intervention, and choice of chemotherapy but have been unable to offer definitive conclusions. CRS and HIPEC remain morbid procedures with complication rates ranging between 30% to 46% in larger series. Accordingly, an increasing interest in identifying molecular targets and developing targeted therapies is emerging. Among such novel targets is sphingosine kinase 1 (SphK1) which regulates the production of sphingosine-1-phosphate, a biologically active lipid implicated in various cancers including malignant mesothelioma. The known action of specific SphK inhibitors may warrant further exploration in peritoneal disease.

Diffuse mesothelioma of the peritoneum: a pathological study of 64 tumours treated with cytoreductive therapy

BACKGROUND

Diffuse peritoneal mesothelioma (DPM) forms a spectrum of indolent surface tumours to malignant invasive cancers. There are few pathological series that span well and poorly differentiated lesions that show diffuse peritoneal spread.

METHODS

Sixty-four DPM treated by initial cytoreductive therapy were retrospectively reviewed. Tumours were classified by surface and invasive growth pattern and correlated with risk factors, peritoneal cancer index (PCI) and completeness of cytoreduction (CCR). Degree of invasion was quantitated as absent (0), into stroma (I), into fat (II), and into adjacent structures (III) and was correlated with cytological features. Selected immunohistochemical stains were performed.

RESULTS

There were three well differentiated papillary mesotheliomas (WDPM; type A), four multicystic mesothelioma (type B), 22 tubulopapillary epithelioid mesotheliomas (type C), and 35 poorly differentiated epithelioid mesotheliomas with solid or sarcomatoid growth (Type D). Seven type D tumours had prominent sarcomatoid areas, 12 deciduoid areas, and four lymphohistiocytoid features. Risk factors were present in all groups except type A, and included prior abdominal surgery (n=24), asbestos exposure (n=5) and radiation (n=2). Extra-pleural mesothelioma was present in all groups except type B (total n=7, 11%). Two type A and eight type C tumours lacked invasion; only type D showed level III invasion. The invasive portion of one type A tumour and two type B tumours showed adenomatoid features. PCI and CCR were greater in type D compared to the other groups (p=0.02), as well as mitotic rate, degree of necrosis, and nuclear pleomorphism (p<0.001). Degree of invasion was strongly correlated with CCR (p=0.007), necrosis (p<0.0001), nuclear grade (p<0.0001), and mitotic rate (p=0.001), but not PCI (p=0.1). Immunohistochemical results were similar across groups, with frequent positivity for CA125 (94%), EGFR (94%) and calretinin (93%), followed by p16 (85%), cytokeratin 5,6 (76%), D2-40 (71%) and WT-1 (47%). PAX-8 was negative in all tumours, except one type A tumour that showed diffuse nuclear positivity.

CONCLUSIONS

Diffuse peritoneal mesotheliomas can be classified into four groups that reflect invasive potential, degree of adverse histological features, and amenability for CCR. Non-invasive tumours include both type A and type C tumours.

Diffuse malignant peritoneal mesothelioma: long-term survival with complete cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy (HIPEC)

BACKGROUND

Prognosis of diffuse malignant peritoneal mesothelioma (DMPM) has been recently improved by cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC). As with other peritoneal surface malignancies, the survival benefit is maximal when a complete surgical cytoreduction is achieved, but additional factors predicting long-term outcome are still poorly understood. We sought to investigate outcome and prognostic factors in patients with DMPM treated by complete cytoreduction and HIPEC.

METHODS

From a prospective database, we selected 108 patients with DMPM undergoing complete cytoreduction (residual tumour nodules ≤2.5 mm) and closed-abdomen HIPEC with cisplatin and doxorubicin or mitomycin-C. Twenty-seven patient-, tumour- and treatment-related variables were assessed by multivariate analysis with respect to overall (OS) and progression-free (PFS) survival. A panel of immunohistochemical markers was tested.

RESULTS

Operative mortality was 1.9% and major morbidity 38.9%. Median follow-up was 48.8 months (95% confidence interval (CI) 37.1-60.6). Median OS and PFS were 63.2 months (95%CI 29.6-96.7) and 25.1 months (95%CI 5.1-45.1). The survival curve reached a plateau after 7 years, representing 19 actual survivors of 39 patients (43.6%) with potential follow-up ≥7 years. Cytokeratin 5/6, calretinin, Wilms tumour-1 (WT-1), podoplanin and epithelial growth factor receptor (EGFR) were mostly positive. At multivariate analysis, epithelial histological subtype, negative lymph-nodes, ≤10% Ki67-positive cells correlated with both increased OS and PFS. Positive podoplanin correlated to increased PFS.

CONCLUSIONS

After complete cytoreduction and HIPEC, prognosis of DMPM is primarily dependent on pathologic and biologic features. Patients with DMPM surviving ≥7 years appeared to be cured. Cure rate was 43.6%. Proliferative index and podoplanin may be used for prognostic stratification.

Malignant peritoneal mesothelioma treated by cytoreductive surgery and hyperthermic intraperitoneal chemotherapy: is GLUT1 expression a major prognostic factor? A preliminary study

PURPOSE

Diffuse malignant peritoneal mesothelioma (DMPM) is a rare primary peritoneal malignancy. Its prognosis has been improved by an aggressive locoregional treatment combining extensive cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Prognostic factors are currently poorly defined for this disease but are essential if treatment is to be standardized.

METHODS

Twenty-eight patients with DMPM, who were considered preoperatively to be candidates for CRS and HIPEC between June 1998 and August 2010 at our institution, were selected for this study. Medical records and histopathological features were retrospectively reviewed and 24 clinical, histological, and immunohistochemical parameters were assessed for their association with overall survival by univariate and multivariate analyses.

RESULTS

The following factors were significantly associated with overall survival by univariate analysis: predominant histological growth pattern in the epithelioid areas, nuclear grooves in the epithelioid areas, atypical mitoses, and calretinin and GLUT1 expression by immunohistochemistry in the epithelioid areas. Expression of the facilitative glucose transporter protein GLUT1 in the epithelioid areas was the only factor independently associated with overall survival by multivariate analysis.

CONCLUSIONS

GLUT1 expression appears to be an indicator of poor prognosis in DMPM. Standard histological classification of DMPM may not be adequate to select patients for aggressive locoregional treatments, such as CRS and HIPEC. Multicenter validation of the prognostic factors identified in this preliminary study is needed to refine patient selection for potential cure.

Cytoreductive surgery with selective versus complete parietal peritonectomy followed by hyperthermic intraperitoneal chemotherapy in patients with diffuse malignant peritoneal mesothelioma: a controlled study

BACKGROUND

Combined treatment involving peritonectomy procedures, multivisceral resections, and hyperthermic intraperitoneal chemotherapy (HIPEC) has reportedly resulted in survival benefit for peritoneal surface malignancies, including diffuse malignant peritoneal mesothelioma (DMPM). Many unanswered questions remain regarding the surgical options in the management of DMPM. The aim of this case–control study was to assess the impact of the type and extent of parietal peritonectomy on survival and operative outcomes.

METHODS

Thirty patients with DMPM undergoing selective parietal peritonectomy (SPP) of macroscopically involved regions, and 30 matched patients undergoing routine complete parietal peritonectomy (CPP), regardless of disease distribution, were retrospectively identified from a prospective database.

RESULTS

Groups were comparable for all characteristics, except for a higher proportion of patients treated before July 2003 and undergoing preoperative systemic chemotherapy in the SPP group. Median follow-up was 86.2 months in the SPP group and 50.3 months in the CPP group. Median overall survival was 29.6 months in the SPP group and not reached in the CPP group; 5-year overall survival was 40.0% and 63.9%, respectively (P = 0.0269). At multivariate analysis, CPP versus SPP was recognized as an independent predictor of better prognosis, along with complete cytoreduction, negative lymph nodes, epithelial histology, and lower MIB-1 labelling index. Morbidity and reoperation rates were not different between groups. No operative mortality occurred. In 12 of 24 patients undergoing CPP, pathologic examination detected disease involvement on parietal surfaces with no evident tumor at surgical exploration.

CONCLUSIONS

CPP improved survival in patients with DMPM undergoing combined treatment. This information may contribute to standardize surgical options for DMPM and other peritoneal malignancies.

Adjuvant bidirectional chemotherapy with intraperitoneal pemetrexed combined with intravenous Cisplatin for diffuse malignant peritoneal mesothelioma

Cytoreductive surgery (CRS) with heated intraoperative intraperitoneal chemotherapy (HIPEC) has emerged as optimal treatment for diffuse malignant peritoneal mesothelioma (DMPM) showing median survivals of 36–92 months. However, recurrences occur frequently even in patients undergoing optimal cytreduction and are often confined to the abdomen. We initiated a Phase II study of adjuvant intraperitoneal pemetrexed combined with intravenous cisplatin for patients undergoing CRS and HIPEC for DMPM. The treatment consisted of pemetrexed 500 mg/m² intraperitoneally and cisplatin 50 mg/m² intravenously given simultaneously on day 1 of every 21 day cycle for 6 cycles. The primary endpoint of the study was treatment related toxicity. From July 2007 until July 2009 ten patients were enrolled. Nine of 10 completed all 6 cycles of adjuvant treatment per protocol. The most common toxicities were fatigue, nausea and abdominal pain grade 1 or 2. There was one grade 3 toxicity consisting of a catheter infection. The median survival for all 10 patients was 33.5 months. Pharmacokinetic analysis of intraperitoneal pemetrexed showed a peritoneal to plasma area under the curve ratio of 70. Our study shows that adjuvant intravenous cisplatin and intraperitoneal pemetrexed can be used following CRS and HIPEC for DMPM with low morbidity.

High Wilms' tumour gene (WT1) expression and low mitotic count are independent predictors of survival in diffuse peritoneal mesothelioma

AIMS

To evaluate the use of the Wilms' tumour gene (WT1) marker and histomorphological parameters as indicators of prognosis in malignant peritoneal mesothelioma (MPM).

METHODS AND RESULTS

Histological samples of 31 MPM were stained immunohistochemically for the WT1 protein. The results were quantified by recording the number of stained nuclei, and then correlated with patient survival. Statistical correlation was evaluated for tumour histotype, mitotic count (MC), nuclear grade (NG), necrosis, lymphoid response (grade of inflammation) and desmoplasia with regard to survival. High-grade histology (solid epithelioid, pure sarcomatoid or biphasic tumours), high NG, MC more than five per 10 per high-power field (HPF), necrosis and desmoplasia were associated with a significantly worse prognosis. Patients with MPM with low WT1 expression (≤25% of positive cells) survived for a significantly shorter time compared to those with high WT1 expression (>25% of positive cells) (P = 0.0001). The 50% survival time of subjects with low WT1 expression was 2.9 months [95% confidence interval (CI): 2.05-3.71] versus 31.5 months (95% CI: 20.4-42.5) for those with high WT1 expression. On multivariate analysis, WT1 and MC were found to be associated independently with survival (P = 0.002; P = 0.005, respectively).

CONCLUSIONS

Our study suggests that low WT1 expression and high MC may be indicative of an unfavourable prognosis in patients with advanced malignant peritoneal mesothelioma.

Diffuse malignant peritoneal mesothelioma: systematic review of clinical management and biological research

Diffuse malignant peritoneal mesothelioma (DMPM) is an uncommon and locally aggressive tumor with poor prognosis. Currently, no standard therapy is available. The biology of this disease is still poorly understood. We performed a systematic search of relevant studies on clinical management and biological research of DMPM. Trials were selected using a predetermined protocol. The current evidence suggests that cytoreductive surgery (CRS) and perioperative intraperitoneal chemotherapy (PIC) results in improved survival. Biological understanding of DMPM is currently evolving.

A novel tumor-node-metastasis (TNM) staging system of diffuse malignant peritoneal mesothelioma using outcome analysis of a multi-institutional database*

BACKGROUND

Currently, no tumor-node-metastasis (TNM) staging system exists for patients with diffuse malignant peritoneal mesothelioma (DMPM). The primary objective was to formulate a clinicopathological staging system through the identification of significant prognostic parameters.

METHODS

Eight international institutions with prospectively collected data on patients who underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy contributed to the registry. Two hundred ninety-four patients had complete clinicopathological data and formed the basis of this staging project.

RESULTS

Peritoneal cancer index (PCI) was categorized into T(1) (PCI 1-10), T(2) (PCI 11-20), T(3) (PCI 21-30), and T(4) (PCI 30-39). Twenty-two patients had positive lymph nodes (N(1) ) and 12 patients had extra-abdominal metastases (M(1) ). The survival for patients with T(1) (PCI 1-10) N(0) M(0) was significantly superior to the other patients. This group of patients is therefore designated as Stage I. The survival of patients with T(2) (PCI 11-20) and T(3) (PCI 21-30), in absence of N(1) or M(1) disease, was similar. This group of patients was categorized as Stage II. The survival of patients with T(4) (PCI 30-39), N(1,) and/or M(1) was similarly poor. This group of patients was therefore categorized as Stage III. Three prognostic factors were independently associated with survival in the multivariate analysis: histological subtype, completeness of cytoreduction, and the proposed TNM staging. The 5-year survival associated with Stage I, II, and III disease was 87%, 53%, and 29%, respectively.

CONCLUSIONS

The proposed TNM staging system resulted in significant stratification of survival by stage when applied to the current multi-institutional registry data.

Clinical implications of novel activating EGFR mutations in malignant peritoneal mesothelioma

Background

There is a paucity of information about the molecular perturbations involved in MPM tumor formation. We previously reported that EGFR-TK mutations in MPM were predictive of achieving optimal surgical cytoreduction, but the status of EGFR pathway activation potential of these mutations was not known. Here we present the mutant EGFR activating potential and the matured survival data of the EGFR mutant(mut+) relative to wild type EGFR(mut-) mesothelioma.

Methods

Twenty-nine patients were evaluated and their tumors were probed for mutations in the catalytic TK-domain. Twenty-five patients were treated with cytoreductive surgery and complete clinical data was available for comparison of the mut+ and mut- groups. A COS-7 cell expression model was used to determine mutation activating profiles and response to erlotinib.

Results

Functional mutations were found in 31%(9/29) of patients; 7 of these mutations were novel and another was the L858R mutation. All missense mutations were found to be activating mutations and responsive to erlotinib. Of the 25 patients managed surgically, there were 7 mut+ and 18 mut-. Two of 7 (29%) mut+ developed progressive disease and died with a median follow-up time of 22 months; while 13/18 (72%) mut- developed progressive disease and 10/18 (56%) died with median TTP of 12 months and median survival of 14 months.

Conclusions

The novel EGFR mutations identified are activating mutations responsive to erlotinib. The mut+ subset have a 'relative' improved outcome. Erlotinib may have a role in MPM and exploration for mutations in a larger patient cohort is warranted.

Receptor tyrosine kinase and downstream signalling analysis in diffuse malignant peritoneal mesothelioma

Our aim was to assess the activation profile of EGFR, PDGFRB and PDGFRA receptor tyrosine kinases (RTK) and their downstream effectors in a series of cryopreserved diffuse malignant peritoneal mesothelioma (DMPM) surgical specimens to discover the targets for drug inhibition. We also made a complementary analysis of the cytotoxic effects of some kinase inhibitors on the proliferation of the human peritoneal mesothelioma STO cell line. We found the expression/phosphorylation of EGFR and PDGFRB in most of the tumours, and PDGFRA activation in half. The expression of the cognate ligands TGF-α, PDGFB and PDGFA in the absence of RTK mutation and amplification suggested the presence of an autocrine/paracrine loop. There was also evidence of EGFR and PDGFRB co-activation. RTK downstream signalling analysis demonstrated the activation/expression of ERK1/2, AKT and mTOR, together with S6 and 4EBP1, in almost all the DMPMs. No KRAS/BRAF mutations, PI3KCA mutations/amplifications or PTEN inactivation were observed. Real-time polymerase chain reaction revealed the decreased expression of TSC1 c-DNA in half of the tumours. In vitro cytotoxicity studies showed the STO cell line to be resistant to gefitinib and sensitive to sequential treatment with RAD001 and sorafenib; these findings were consistent with the presence of the KRAS mutation G12D in these cells although it was not detectable in the original tumour. Our results highlight the ligand-dependent activation and co-activation of EGFR and PDGFRB, as well as a connection between these activated RTKs and the downstream mTOR pathway, thus supporting the role of combined treatment with RTK and mTOR inhibitors in DMPM.

Cytoreductive surgery with intraperitoneal hyperthermic chemotherapy for malignant peritoneal mesothelioma: mitomycin versus cisplatin

BACKGROUND

Malignant peritoneal mesothelioma (MPM) is a rare, rapidly fatal disease. Because traditional treatments offer little benefit, there has been increasing interest in cytoreductive surgery (CS) with intraperitoneal hyperthermic chemotherapy (IPHC). The most efficacious chemotherapy regimen is not established. Herein we report clinical outcomes of MPM patients treated with CS and IPHC and contrast results using two chemoperfusates: mitomycin and cisplatin.

METHODS

Thirty-four patients were treated for MPM. Following CS, 19 patients underwent IPHC with mitomycin and 15 received cisplatin. Overall survival, disease-free survival, and progression-free survival were compared between the two groups.

RESULTS

Overall survival was 56 and 17% at 3 and 5 years, with median survival of 40.8 months. Those perfused with cisplatin were more likely to be alive at 1, 2, and 3 years (P < 0.05, 0.05, and 0.04, respectively). Median survival for mitomycin and cisplatin was 10.8 and 40.8 months, respectively (P = 0.22). Median disease-free survival and progression-free survival were 10.3 and 9.1 months, respectively. There was a trend toward improved disease-free and progression-free survival using cisplatin.

CONCLUSIONS

CS with IPHC is a promising modality for patients with MPM, and clinical outcomes appear to be improved using cisplatin. We recommend using high-dose intraperitoneal cisplatin following cytoreductive surgery when treating malignant peritoneal mesothelioma.

Experience with peritoneal mesothelioma at the Milan National Cancer Institute

Diffuse malignant peritoneal mesothelioma (DMPM) is an uncommon and rapidly fatal tumor. Therapeutic options have traditionally been limited and ineffective. The biologic and molecular events correlated with poor responsiveness to therapy are still poorly understood. In recent years, an innovative treatment approach involving aggressive cytoreductive surgery (CRS) and perioperative intraperitoneal chemotherapy has reportedly resulted in improved outcome, as compared to historical controls. Since 1995, at the National Cancer Institute (NCI) of Milan (Italy), patients with DMPM have been treated with CRS and hyperthermic intra-peritoneal chemotherapy (HIPEC). In the present paper, clinical experiences and basic science investigations on DMPM at Milan NCI are reviewed. Peri-operative and long-term outcome results with CRS and HIPEC are presented. Clinico-pathological prognostic factors were investigated by multivariate analysis. The pathologic features and immunohistochemical markers related to DMPM biologic behavior were assessed in a large case-series uniformly treated at our institution. The prevalence and prognostic role of telomere maintenance mechanisms, which account for the limitless cell replicative potential of many malignancies, were studied. The dysregulation of the apoptotic pathways may play a role in the relative chemo-resistance of DMPM and a better understanding of apoptosis-related mechanisms could result in novel targeted therapeutic strategies. On this basis, the expression of survivin and other IAP family members (IAP-1, IAP-2, and X-IAP), the pro-apoptotic protein Smac/DIABLO, and antigens associated with cell proliferation (Ki-67) and apoptosis (caspase-cleaved cytokeratin-18) were analyzed. Finally, analyses of EGFR, PDGFRA and PDGFRB were performed to ascertain if deregulation of RTK could offer useful alternative therapeutic targets.

Diffuse malignant peritoneal mesothelioma presenting as intestinal obstruction

Diffuse malignant peritoneal mesothelioma (DMPM) represents 90% of all peritoneal forms of mesothelioma. It affects mainly patients 50-69 years old. In 50% of cases there is a history of asbestos exposure. The clinical presentation of the disease is not characteristic: nonspecific abdominal pain, weight loss, and abdominal distension are common. Ascites occurs in 90% of the patients. Bowel obstruction is a late manifestation. We present three patients with DMPM, without a history of asbestos exposure and without ascites, who presented with complete bowel obstruction. All patients underwent emergency operations, and palliative surgical procedures were performed. Each patient died within 3 to 6 months postoperatively.

Malignant peritoneal mesothelioma

Malignant mesothelioma is a highly aggressive neoplasm. The incidence of malignant mesothelioma is increasing worldwide. Diffuse malignant peritoneal mesothelioma (DMPM) represents one-fourth of all mesotheliomas. Association of asbestos exposure with DMPM has been observed, especially in males. The great majority of patients present with abdominal pain and distension, caused by accumulation of tumors and ascitic fluid. In the past, DMPM was considered a pre-terminal condition; therefore attracted little attention. Patients invariably died from their disease within a year. Recently, several prospective trials have demonstrated a median survival of 40 to 90 mo and 5-year survival of 30% to 60% after combined treatment using cytoreductive surgery and perioperative intraperitoneal chemotherapy. This remarkable improvement in survival has prompted new search into the medical science related to DMPM, a disease previously ignored as uninteresting. This review article focuses on the key advances in the epidemiology, diagnosis, staging, treatments and prognosis of DMPM that have occurred in the past decade.

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for malignant peritoneal mesothelioma: multi-institutional experience

PURPOSE

This multi-institutional registry study evaluated cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) for diffuse malignant peritoneal mesothelioma (DMPM).

PATIENTS AND METHODS

A multi-institutional data registry that included 405 patients with DMPM treated by a uniform approach that used CRS and HIPEC was established. The primary end point was overall survival. The secondary end point was evaluation of prognostic variables for overall survival.

RESULTS

Follow-up was complete in 401 patients (99%). The median follow-up period for the patients who were alive was 33 months (range, 1 to 235 months). The mean age was 50 years (standard deviation [SD], 14 years). Three hundred eighteen patients (79%) had epithelial tumors. Twenty-five patients (6%) had positive lymph nodes. The mean peritoneal cancer index was 20. One hundred eighty-seven patients (46%) had complete or near-complete cytoreduction. Three hundred seventy-two patients (92%) received HIPEC. One hundred twenty-seven patients (31%) had grades 3 to 4 complications. Nine patients (2%) died perioperatively. The mean length of hospital stay was 22 days (SD, 15 days). The overall median survival was 53 months (1 to 235 months), and 3- and 5-year survival rates were 60% and 47%, respectively. Four prognostic factors were independently associated with improved survival in the multivariate analysis: epithelial subtype (P < .001), absence of lymph node metastasis (P < .001), completeness of cytoreduction scores of CC-0 or CC-1 (P < .001), and HIPEC (P = .002).

CONCLUSION

The data suggest that CRS combined with HIPEC achieved prolonged survival in selected patients with DMPM.

Lymph node metastases in diffuse malignant peritoneal mesothelioma

BACKGROUND

Improved survival has been reported for diffuse malignant peritoneal mesothelioma (DMPM) treated by surgical cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC). The significance of lymph node involvement in this disease is still poorly understood.

METHODS

Prospectively collected clinical data on 83 consecutive patients with DMPM undergoing surgical cytoreduction and closed-abdomen HIPEC with cisplatin and doxorubicin were reviewed. Clinically suspicious lymph nodes were submitted to pathological examination. The impact of nodal involvement on survival was assessed by multivariate analysis; 14 clinicopathological control variables were tested.

RESULTS

For the overall series, median follow-up was 52 months (range 1-126 months) and 5-year overall survival (OS) was 49.5%. Lymph nodes were submitted to pathological examination in 38 patients, being positive in 11 and negative in 27. Lymph nodes were not clinically suspicious and not sampled in 45 patients. Iliac (n = 7) and paracolic (n = 2) nodes were the most commonly involved nodes. OS was 18.0% for patients with pathologically positive nodes and 82.5% for those with pathologically negative nodes (P = 0.0024). On multivariate analysis, pathologically negative (versus positive/not assessed) nodes [hazard ratio (HR) = 2.81; 95% confidence interval (CI) = 1.12-7.05; P = 0.027], epithelial subtype (HR = 2.93; CI = 1.24-6.95; P = 0.015), mitotic count <or=5/50 high-power microscopic fields (HPF) (HR = 5.34; CI = 1.96-14.54; P = 0.001), and completeness of cytoreduction (HR = 2.06; CI = 1.19-3.56; P = 0.001) correlated with increased OS. Positive nodes (versus negative/not assessed) did not significantly correlate with survival.

CONCLUSION

Pathologically negative nodes (as compared with pathological positive and not assessed), along with pathological and biological features, independently correlated with increased survival following comprehensive treatment. This suggests the need for careful node sampling when performing surgical cytoreduction for DMPM patients.

Malignant abdominal mesothelioma: defining the role of surgery

OBJECTIVE

Determine the role of surgery for patients with malignant abdominal mesotheliomas (MAMs).

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database (1973-2005) was queried.

RESULTS

Overall, 10,589 cases of malignant mesotheliomas were identified. Of these, 9,211 cases were thoracic (TM) and 1,112 cases were MAM (10.5%). Patients with TM presented with more localized disease than those patients with MAM (P < 0.001). MAM more often affected younger patients (63 years vs. 71 years) (P < 0.001). The annual incidence of MAM was approximately 1.00 case per 100,000 in 2005. Overall median survival for MAM patients was 8 months, with a significant difference between women and men (13 months vs. 6 months, respectively) (P < 0.001). Patients who successfully underwent surgical resection had a considerably longer median survival (20 months vs. 4 months, P < 0.001) as well as a significantly higher 5-year survival (28% vs. 12%, P < 0.001). Multivariate analysis identified that a poorly differentiated tumor grade, failure to undertake surgical resection, advanced age, and male gender were all independent predictors of poorer outcome.

CONCLUSION

Surgical extirpation of MAM may be associated with significantly improved survival. All patients with MAM should be evaluated for potential surgical resection.

Diffuse malignant peritoneal mesothelioma: Failure analysis following cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC)

Improved survival has been reported for diffuse malignant peritoneal mesothelioma (DMPM) treated by cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC). The issue of treatment failure has never been extensively addressed. The present study assessed the failure pattern, management, and outcome of progressive DMPM following comprehensive treatment. Clinical data on 70 patients with DMPM undergoing cytoreduction and HIPEC were prospectively collected; after a median follow-up of 43 months, disease progression occurred in 38 patients. Progressive disease distribution in 13 abdominopelvic regions was analyzed. In 28 patients undergoing adequate cytoreduction (residual tumor < or =2.5 mm), clinicopathological factors correlating to disease progression in each region were investigated. Median time to progression was 9 months [95% confidence interval (CI) 1.6-35.9]. Median survival from progression was 8 months (95% CI 4-16.2). The failure pattern was categorized as peritoneal progression (n = 31), liver metastases (n = 1), abdominal lymph-node involvement (n = 2), pleural seeding (n = 4). Small bowel was the single site most commonly involved (n = 27). Residual tumor < or =2.5 mm (versus no visible) was the only independent risk factor for disease progression in epigastric region (P = 0.047), upper ileum (P = 0.029), upper jejunum (P = 0.034), and lower jejunum (P = 0.002). Progressive disease was treated with second HIPEC in 3 patients, debulking in 4, systemic chemotherapy in 16, and supportive care in 15. At multivariate analysis, time to progression <9 months (P = 0.009), poor performance status (P = 0.005), and supportive care (P = 0.003) correlated to reduced survival from progression. We conclude that minimal residual disease, compared with macroscopically complete cytoreduction, correlated to failure in critical anatomical areas, suggesting the need for maximal cytoreductive surgical efforts. In selected patients, aggressive management of progressive disease seems worthwhile.

Novel and existing mutations in the tyrosine kinase domain of the epidermal growth factor receptor are predictors of optimal resectability in malignant peritoneal mesothelioma

Malignant peritoneal mesotheliomas (MPM) are rare tumors representing 20% of all malignant mesothelioma cases. The median survival for these tumors is less than a year, and like other peritoneal surface malignancies, this is due primarily to intra-abdominal recurrence and progression. Currently there is a paucity of information about the biology of these tumors and molecular perturbations that are involved in tumor formation. Elucidation of mutations and biological pathways active in these tumors may identify valuable prognostic markers, as well as facilitate the development of novel therapies. In this study, we investigate the predictive value of epidermal growth factor receptor (EGFR) mutations in achieving optimal resectability. Twenty-nine patients with MPM were evaluated at a single tertiary care center and their tumors were probed for point mutations in the catalytic TK domain of epidermal growth factor receptor (mut+). All specimens were examined for somatic mutations by polymerase chain reaction amplification, and all variants were confirmed by multiple independent amplifications. Twenty-five patients were treated with cytoreductive surgery with or without intraperitoneal hyperthermic chemotherapy and complete clinical data including age, sex, cytoreductive score, mutation, and survival were available for comparison of the mut+ and mut- groups. The median age was 56 years, 71% of the patients were male, and the median follow-up time was 14.5 months. Mutations were found in 31% (9 of 29) of the tumors. Seven of these mutations were novel, and one was the L858R mutation described in non-small-cell lung cancer. Of the 25 patients managed surgically, 7 had mut+ and 18 wild type (mut-) disease. Optimal resectability was achieved in 7 (100%) of 7 of mut+ group and 9 (50%) of 18 mut- (p = .026). All mut+ patients are alive with a mean follow-up time of 24 months, whereas 5 (28%) of 18 of the mut- group are dead of disease with a mean follow-up time of 7 months (p = .27). In an analysis of covariance model, only optimal resectability (p = .04) was found to be predictive of survival. EGFR-TK seems to be a common site for mutation in MPM, with mutations being identified in 31% of patients. The EGFR mutations identified included the L858R activating mutation, as well as eight novel EGFR-TK catalytic domain point mutations. These mutations were predictive of optimal resectability, which was the only variable found to be predictive of survival. With longer follow-up, mut+ may not only be predictive of survival but may represent a subset of patients whose disease may be responsive to TK-inhibitor therapy. Experiments confirming the activating properties of the novel mutations are warranted.

Peritoneal mesothelioma

OPINION STATEMENT

Malignant peritoneal mesothelioma (MPM) is an aggressive neoplasm that rapidly spreads within the confines of the abdominal cavity to involve most accessible peritoneal and omental surfaces. Current treatment options are unsatisfactory, and new approaches are needed. Recent publications have reported improved survival with an intensive loco-regional treatment strategy including cytoreductive surgery (CRS) along with hyperthermic intraperitoneal chemotherapy (HIPEC). We have noted at our institution prolonged survival in selected patients after intensive multimodality treatment. Our most recently reported trial included initial laparatomy with omentectomy, resection of peritoneal implants, and placement of bilateral peritoneal Portacath; repeated courses of intraperitoneal chemotherapy with doxorubicin, cisplatin, and interferon gamma; second-look laparotomy; and intraoperative hyperthermic perfusion with mitomycin and cisplatin, followed by whole abdominal radiation. To date there have been no universally accepted treatments for MPM. Unless referred to a specialty center, patients are routinely treated with pemetrexed and cisplatin which has been shown to increase survival in pleural mesothelioma.

Multiple mechanisms of telomere maintenance exist and differentially affect clinical outcome in diffuse malignant peritoneal mesothelioma

PURPOSE

This study aims to investigate the prevalence of the two known telomere maintenance mechanisms, telomerase activity (TA) and alternative lengthening of telomeres (ALT), and to assess their prognostic relevance in diffuse malignant peritoneal mesothelioma (DMPM).

EXPERIMENTAL DESIGN

In 44 DMPM specimens obtained from 38 patients, TA was determined using the telomeric repeat amplification protocol and ALT was detected by assaying ALT-associated promyelocytic leukemia nuclear bodies. The prognostic significance of telomere maintenance mechanisms was analyzed by Cox regression in the overall series and in a subset of 29 patients who underwent a uniform treatment regimen consisting of cytoreductive surgery and hyperthermic i.p. chemotherapy.

RESULTS

Telomere maintenance mechanisms were detectable in 86.4% of DMPM: ALT or TA alone was found in 18.2% or 63.6% of lesions, respectively, whereas two cases (4.6%) were ALT+/TA+. TA and ALT proved to be inversely associated (P = 0.002). In the overall series, TA was prognostic for 4-year relapse (TA+ versus TA-, hazard ratio, 3.30; 95% confidence interval, 1.23-8.86; P = 0.018) and cancer-related death (TA+ versus TA-, hazard ratio, 3.56; 95% confidence interval, 1.03-12.51; P = 0.045), whereas ALT failed to significantly affect clinical outcome. These results held true also in the subset of patients submitted to uniform treatment with cytoreductive surgery and hyperthermic i.p. chemotherapy.

CONCLUSIONS

Our results indicate that both known telomere maintenance mechanisms, TA and ALT, are present in DMPM and differentially affect patient prognosis.

Malignant peritoneal mesothelioma: treatment with maximal cytoreductive surgery plus intraperitoneal chemotherapy

OBJECTIVE

To report survival results in patients with diffuse malignant peritoneal mesothelioma (MPM) treated with maximal cytoreductive surgery followed by immediate intraperitoneal chemotherapy, and to compare them with the median survival of 12-24 months obtained with the standard treatment based on systemic chemotherapy.

PATIENTS AND METHODS

Twenty-six patients underwent this new regional approach and a median follow-up of 55 months was achieved after this treatment. Complete cytoreductive surgery (residual disease < 2 mm) was performed in all but one patient. Intraperitoneal chemotherapy was performed with hyperthermia (4245 degrees C) and oxaliplatin in 22 patients. The last 12 patients additionally received irinotecan. Data were prospectively verified and retrospectively analyzed.

RESULTS

One patient died postoperatively (4%), and morbidity attained 54%. The median survival exceeded 100 months and the overall 5-year survival rate was 63%. This small series lacks the statistical power required to conduct a well-grounded study on prognostic factors, particularly as the completeness of the surgery is not analyzable here. However, the low-grade histological types had a better disease-free survival rate that was of borderline significance compared to their high-grade counterparts.

CONCLUSION

This new approach combining complete cytoreductive surgery considerably increases the survival of patients with MPM compared with the standard treatment based on systemic chemotherapy.

Pathology of mesothelioma

The incidence of mesothelioma has been gradually increasing in Japan, and the underlying factor for this is considered to be the increase in the amount of asbestos imported into Japan between 1960 and 1975. Mesothelioma can be roughly divided into localized and diffuse types, but the former is extremely rare. In making a diagnosis of mesothelioma, it is important to confirm the location of tumor and the specific gross findings before histological examination. Mesothelioma can be categorized histologically as epithelioid type, sarcomatoid type, biphasic type, desmoplastic type, among others. It can take many forms; consequently, there are many diseases to be differentiated when the diagnosis of mesothelioma is based on histological analyses. Immunohistochemical stains are useful for making a diagnosis, but the correct combination of antibodies as positive or negative markers should be selected and a comprehensive assessment of the staining results is necessary. The accuracy of the pathological diagnosis is very important to the patients because they can be receive official compensation or relief when the diagnosis of mesothelioma is confirmed. Under present conditions, both clinicians and pathologists must make a concerted effort to improve the accuracy of the diagnosis of mesothelioma.

Systematic review of cytoreductive surgery and heated intraoperative intraperitoneal chemotherapy for treatment of peritoneal carcinomatosis in primary and recurrent ovarian cancer

The aim of this systematic review is to critically evaluate cytoreductive surgery combined with heated intraoperative intraperitoneal chemotherapy in the treatment of ovarian cancer. A systematic review of all manuscripts published in the English literature that met predetermined inclusion criteria was carried out. Data concerning cytoreductive surgery, method and agents for administration of heated intraoperative intraperitoneal chemotherapy, morbidity, mortality, hospital stay and survival were extracted, critically reviewed and tabulated. Fourteen studies were analyzed. A wide variety of drug doses, methods of intraperitoneal chemotherapy administration and volume of chemotherapy solution were used. Seven studies showed that patients with complete cytoreduction had the greatest benefit. The median overall survival for primary and recurrent disease ranged from 22 to 54 months and the median disease-free survival from 10 to 26 months. The rates of significant morbidity associated with this combined treatment were low, ranging from 5% to 36%. The median mortality was 3% (range 0%-10%). Cytoreductive surgery combined with heated intraoperative intraperitoneal chemotherapy is a treatment option for patients with ovarian cancer that is worthy of further investigation. Selection criteria for patients most likely to benefit need to be defined.

Multicystic and well-differentiated papillary peritoneal mesothelioma treated by surgical cytoreduction and hyperthermic intra-peritoneal chemotherapy (HIPEC)

BACKGROUND

Multicystic peritoneal mesothelioma (MPM) and well-differentiated papillary peritoneal mesothelioma (WDPPM) are exceedingly uncommon lesions with uncertain malignant potential and no uniform treatment strategy. The aim of the current study was to review our experience with cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC) in these clinical settings.

METHODS

Four women with MPM and eight with WDPPM underwent 13 procedures of cytoreduction and close-abdomen HIPEC with cis-platin and doxorubicin. Seven patients had recurrent disease after previous debulking (one operation in five patients, two in one, four in one). Potential clinicopathological prognostic factors were assessed.

RESULTS

Optimal cytoreduction (residual tumor nodules <or=2.5 mm) was performed in 12 of 13 procedures. Median follow-up was 27 months (range 6-94). One grade 4 postoperative complication (NCI/CTCAE v.3.0) and no operative mortalities occurred. One patient underwent the procedure twice due to locoregional MPM recurrence. Transition of typical WDPPM to malignant biphasic mesothelioma was documented in one patient who died of disease progression following incomplete cytoreduction and HIPEC. Following multimodality treatment, 5-year overall and progression-free survival were 90.0% (standard error = 9.0) and 79.7% (11.9), respectively. Progression-free survival following previous debulking surgery (median 24 months; range 2-87) was statistically worse (P = .0156). Incomplete cytoreduction and poor performance status correlated to both reduced overall and progression-free survival after cytoreduction and HIPEC.

CONCLUSIONS

MPM and WDPPM are borderline tumors capable of transformation into potentially lethal processes. Definitive tumor eradication by means of cytoreduction and HIPEC seems more effective than debulking surgery in preventing disease recurrence or transition to aggressive malignancies.

Sex difference in diffuse malignant peritoneal mesothelioma

BACKGROUND

Diffuse malignant peritoneal mesothelioma (DMPM) is rare and in the past has proved an invariably fatal disease. Female patients have been reported to have an improved survival outcome for reasons that are not understood.

METHODS

The survival of 34 men and 28 women who underwent cytoreduction and perioperative intraperitoneal chemotherapy for DMPM was compared. Twenty-five clinicopathological variables were subjected to univariate analysis.

RESULTS

The women had a 5-year survival rate of 63 per cent and median survival was not reached. The men had a 5-year survival rate of 42 per cent, with a median survival of 32 months (P = 0.045). Women had undergone more extensive previous surgery and had less extensive peritoneal involvement at the time of cytoreduction. Tumours in women more frequently showed a small nuclear size (30 microm or less) and the chromatin pattern was more often granular than clear.

CONCLUSION

Women with DMPM had better survival. This observation may be related to the favourable clinical and histopathological features associated with women.