Two-stage operative cytoreduction and intraperitoneal chemotherapy for diffuse malignant peritoneal mesothelioma: Operative morbidity and mortality in phase I and II trials

AIMS

The standard of care for diffuse malignant peritoneal mesothelioma involves operative cytoreduction and intraperitoneal chemotherapy. Most centers favor aggressive operative cytoreduction, accepting high morbidity and mortality. In our trials, patients underwent less extensive cytoreduction followed by prolonged intraperitoneal chemotherapy. Patients underwent a second cytoreduction with heated intraperitoneal chemotherapy. We hypothesized this would result in lower operative morbidity and mortality with similar survival.

METHODS

Hospital records, discharge summaries, microbiology, radiography, and office records were retrospectively reviewed to supplement a prospective database. 30-day morbidity and mortality were categorized, and classified according to the Clavien methodology.

RESULTS

47 first and 39 second operations were performed with 13% and 26% morbidity, respectively. Mortality was 2%. Infections comprised 59% of the morbidity. Inclusive of both operations, formal peritonectomy was performed in 16% of patients, resection of isolated lesions in less than half, and only 19% had a visceral organs other than the spleen resected. At the completion of the protocol, only 3% of patients had visible intraperitoneal disease. The mean total length of stay for both operations combined was 16 ± 23 days. Overall median survival was 54.9 months, and median survival for the epithelioid subtype was 70.2 months.

CONCLUSIONS

A two-stage cytoreduction with intraperitoneal chemotherapy offers median survival comparable to one-stage protocols, with relatively low morbidity, mortality, visceral resections and length of stay despite two operations. This series supports that our protocol is a feasible and safe approach.

Influence of microscopic malignant peritoneal mesothelioma on posttreatment survival

e15534

Background: Progression of malignant peritoneal mesothelioma to clinically evident disease is poorly understood. Operative cytoreduction and post-operative intraperitoneal chemotherapy, followed by a second operative cytoreduction with heated intraoperative intraperitoneal chemotherapy is protocol at Columbia University. Our ability to assess presence of microscopic disease at a unique second operation provides in vivo insight into disease progression. Methods: Operative, pathology and oncologist records were reviewed for 98 consecutive patients with peritoneal mesothelioma treated between 5/95 and 1/08. Microscopic disease was defined as positive pathology on random biopsies in the absence of gross disease at second operation, and disease-free as absence of gross and microscopic disease. Survival was defined as time from first operation to death or last follow-up. Survival and recurrence were compared using the Kaplan Meier and log-rank methods, and correlations by Fisher's exact method. Results: 98 first and 69 second operations were performed. Patients were 59% male, 88% Caucasian and mean age was 52. At the second operation, 38 had gross disease, 23 were disease-free and 8 had microscopic disease. Median follow-up was 21 months, median overall survival was 48 months, and median survival for the epithelial subtype was 64 months. There was no significant difference in survival between disease- free and microscopic pathologies (log-rank p<0.69). 72% of disease-free (SE 11%) and 80% (SE 18%) of those with microscopic disease were alive at 96 months. 16% of disease-free and 7% of patients with microscopic disease had a recurrence (p<0.4). The time to clinical recurrence for both disease-free and microscopic disease was not significantly different (log-rank p<0.88). Conclusions: Survival and clinical recurrence in those with microscopic disease, none of whom were treated for this entity, were not significantly different from those who were disease-free at the second operation. These in vivo after treatment findings suggest that malignant peritoneal mesothelioma may progress slowly from microscopic to clinical disease and can be closely monitored rather than aggressively treated after initial cytoreduction and intraperitoneal chemotherapy.

No significant financial relationships to disclose.

The use of in-vitro drug resistance levels as a predictor of outcome in soft tissue sarcoma

20510

Background: We have assayed in-vitro drug resistance and immunohistochemical staining for drug resistance markers (MDR-1, MRP) in patients with metastatic soft tissue sarcoma patients. We looked at resistance to Cisplatin, Doxorubicin, and Ifosphamide, prior to beginning chemotherapy. The aim of this study was to investigate the validity of in-vitro drug resistance testing as a predictor of outcome. Methods: Viable tumor samples obtained at time of recurrence or metastasis from 13 patients with metastatic soft tissue sarcoma were tested by a semiquantitative 12 hour tritiated-thymidine uptake cell-proliferation assay (EDR test, Oncotech Inc., Tusin, California) for resistance to the chemotherapy drugs cisplatin, doxorubicin, and ifosphamide. The mean drug resistance level for these three drugs was plotted against survival in months, both from time of metastasis and time of initiation of chemotherapy. Mean resistance was also correlated with positive staining for either MDR-1 or MRP. Results: There was no relationship found between the mean drug resistance and survival, either from time of metastasis (correlation coefficient -0.0596) or time of initiation of chemotherapy (correlation coefficient - 0.1864). There was no correlation between mean drug resistance and; 1) presence of MDR-1 staining (correlation coefficient -0.1269), 2) presence of MRP staining (correlation coefficient -0.2175), 3) presence of either staining for MDR-1 or MRP (correlation coefficient -0.2636). Conclusions: 1) In-vitro drug resistance is not predictive of outcome in patients with soft tissue sarcoma. 2) There is no correlation between the mean drug resistance and positive staining for either MDR-1 or MRP.

No significant financial relationships to disclose.

18FDG-PET in the management of malignant peritoneal mesothelioma: A retrospective review of 145 scans in 37 patients

20519

Background: Malignant peritoneal mesothelioma is a rare tumor best managed by an interdisciplinary approach. The role of 18FDG-PET scans in monitoring patients with peritoneal mesothelioma has not been defined. Methods: Patients with peritoneal mesothelioma treated at Columbia University (October, 1997 - October, 2006) who had a PET scan were reviewed. Data were gathered on modes of therapy, imaging, and clinical outcome. The frequency with which PET scans led to a change in management, defined as scans that led to a biopsy or initiation of chemotherapy, was evaluated. Results: 37 patients, 21 women (57%) and 16 men (43%), were reviewed. The median age was 50 (range 14 - 79) years. All patients underwent surgery, 35 (95%) intraperitoneal chemotherapy, 15 (41%) external beam radiation, and 17 (46%) intravenous chemotherapy. At 43 (range 8.5 - 127) months median follow-up, 27 (73 %) are alive. Among 145 PET scans, 66 (46%) were PET/CT scans, 52 (26%) were PET scans with a CT scan performed within one month, and 27 (19%) were PET scans only. 8 (6%) of PET scans were for initial staging, and 137 (95%) for monitoring. A change in management based on findings in PET imaging occurred in 11 (30%) patients and 14 (10%) scans. Two patients were started on salvage chemotherapy without further evaluation. Two were diagnosed with peritoneal recurrence, 1 with lung metastasis, 1 with lymph node metastasis, 1 with a second malignancy, and 3 with colon polyps. One had a false positive scan, proven by negative surgical biopsy. PET provided early detection of disease progression in 6 (16%) of patients evaluated. One patient (3%) had biopsy proven progressive disease despite no 18FDG uptake on PET scan. Conclusions: 18FDG-PET findings changed management in 30% of patients with peritoneal mesothelioma undergoing multimodality therapy, and provided early detection of recurrence in 16% of patients. Further evaluation of test characteristics and prognostic value of 18FDG-PET in the setting of peritoneal mesothelioma is warranted.

No significant financial relationships to disclose.

Molecular profiling of malignant peritoneal mesothelioma identifies the ubiquitin–proteasome pathway as a therapeutic target in poor prognosis tumors

Malignant mesothelioma is an aggressive neoplastic proliferation derived from cells lining serosal membranes. The biological and clinical characteristics of epithelial type malignant mesothelioma are distinct from those of biphasic and sarcomatous type tumors. The goal of our study was to examine the molecular basis for this distinction. Microarray analysis confirmed that the molecular signatures of epithelial and biphasic histologic subtypes were distinct. Among the differentially expressed functional gene categories was the ubiquitin-proteasome pathway, which was upregulated in biphasic tumors. Cytotoxicity experiments indicated that 211H cells derived from biphasic tumors were synergistically sensitive to sequential combination regimens containing the proteasome inhibitor bortezomib and oxaliplatin. The mechanism of this synergistic response, which was not detected in cells of epithelial tumor origin, was apoptosis. Together, our results identify the ubiquitin-proteasome pathway as a biomarker of poor prognosis biphasic peritoneal mesothelioma tumors and suggest that proteasome inhibitors could increase the effectiveness of cytotoxic chemotherapy in this subset of patients.

Phase II trial of oxaliplatin and gemcitabine in patients with malignant pleural or peritoneal mesothelioma

17133

Background: A prior phase II trial of oxaliplatin and gemcitabine in malignant pleural mesothelioma reported activity with a 40% partial response rate and stable disease in 24% of 25 previously untreated patients (Schutte W. et al., Clin Lung Cancer 2003;4:294). This trial was designed to further evaluate the efficacy of oxaliplatin and gemcitabine in patients with malignant pleural or peritoneal mesothelioma. Methods: Patients with histologically-confirmed malignant pleural or peritoneal mesothelioma not amenable to curative surgical treatment are eligible for enrollment on this single-institution phase II trial. One prior chemotherapy regimen is allowed, including pemetrexed with a platinum compound or gemcitabine. Presence of at least one radiologically-measurable lesion that has not been previously irradiated is required. Gemcitabine 1000 mg/m2 IV over 90 minutes is administered followed by oxaliplatin 100 mg/m2 IV over 2 hours on day 1 of a 14-day cycle. Treatment is continued for at least 6 cycles unless unacceptable toxicity or disease progression occurs. The primary outcome is to evaluate efficacy as measured by tumor response rate. The sequential two-stage design allows for enrollment of a total of 29 patients if 3 of 18 patients enrolled in the first stage have at least a partial response. Results: Ten eligible patients have been enrolled thus far and 6 are evaluable for response. Sites of disease include pleural (3) and peritoneal (3), and histologic subtypes are epithelioid (5) and sarcomatoid (1). Four patients had received prior chemotherapy. A total of 42 cycles have been given with a median of 8 cycles per patient. There are no partial or complete responses. Four patients have had stable disease for at least 4 months. Two patients with stable disease had received prior pemetrexed/gemcitabine or pemetrexed/cisplatin. Frequently observed toxicities include grade II fatigue, neuropathy and upper gastrointestinal dysmotility. Conclusion: This regimen of gemcitabine and oxaliplatin may provide disease stabilization in a subset of patients with malignant pleural and peritoneal mesothelioma, including those who have received prior chemotherapy. The regimen is well-tolerated. This study remains open to accrual.

No significant financial relationships to disclose.

Molecular profiling of malignant peritoneal mesothelioma identifies the ubiquitin-proteasome pathway as a therapeutic target in poor prognosis tumors

9549

Background: Malignant peritoneal mesothelioma (MPM) is an aggressive neoplasm derived from cells lining serosal membranes. The characteristics of the epithelial (E) type MPM are distinct from those of the biphasic and sarcomatous (BS) type tumors. The goal of our study was to examine the molecular basis for this distinction. Methods: We used global molecular profiling with DNA microarrays to identify pathways associated with histologic subtype of 16 MPM tumor specimens acquired from patients entered into pilot multimodality protocols at our Institution. We performed immunohistochemistry on a tissue microarray and quantitative-real time PCR to validate the microarray results. Results: We performed average linkage agglomerative hierarchical clustering using microdissected MPM specimens and normal peritoneal tissue. The tumors segregated into two clades associated with histological subtype, which were distinct from the controls. 476 genes were differentially expressed between E and BS histologic classes (P < .001, with permutation test P value of .001). To identify biologically important differentially expressed genes and pathways, we examined the functional annotation of mesothelioma histologic subtype classifiers using the Pathway Comparison tool of BRB-Array. Among the differentially expressed categories was the ubiquitin-proteasome (UP) pathway, which was upregulated in BS tumors. Cytoxicity experiments by MTS assay indicated that, by the computation of combination indexes of activity, cells derived from BS tumors were exquisitely sensitive to sequential combination regimens containing the proteasome inhibitor (PI) bortezomib and oxaliplatin. The mechanism of this synergistic response, which was not detected in cells of E tumor origin, was apoptosis. Conclusions: Together, our results identify the ubiquitin-proteasome pathway as a biomarker of poor prognosis biphasic and sarcomatous malignant peritoneal mesothelioma tumors and suggest that proteasome inhibitors could increase the effectiveness of cytotoxic chemotherapy in this subset of patients.

No significant financial relationships to disclose.