The Role of Hyperthermic Intraperitoneal Chemotherapy in Pseudomyxoma Peritonei After Cytoreductive Surgery.

Importance: Studies on the prognostic role of hyperthermic intraperitoneal chemotherapy (HIPEC) in pseudomyxoma peritonei (PMP) are currently not available. Objectives: To evaluate outcomes after cytoreductive surgery (CRS) and HIPEC compared with CRS alone in patients with PMP. Design, Setting, and Participants: This cohort study analyzed data from the Peritoneal Surface Oncology Group International (PSOGI) registry, including 1924 patients with histologically confirmed PMP due to an appendiceal mucinous neoplasm. Eligible patients were treated with CRS with or without HIPEC from February 1, 1993, to December 31, 2017, and had complete information on the main prognostic factors and intraperitoneal treatments. Inverse probability treatment weights based on the propensity score for HIPEC treatment containing the main prognostic factors were applied to all models to balance comparisons between the CRS-HIPEC vs CRS-alone groups in the entire series and in the following subsets: optimal cytoreduction, suboptimal cytoreduction, high- and low-grade histologic findings, and different HIPEC drug regimens. Data were analyzed from March 1 to June 1, 2018. Interventions: HIPEC including oxaliplatin plus combined fluorouracil-leucovorin, cisplatin plus mitomycin, mitomycin, and other oxaliplatin-based regimens. Main Outcomes and Measures: Overall survival, severe morbidity (determined using the National Cancer Institute Common Terminology for Adverse Events, version 3.0), return to operating room, and 30- and 90-day mortality. Differences in overall survival were compared using weighted Kaplan-Meier curves, log-rank tests, and Cox proportional hazards multivariable models. A sensitivity analysis was based on the E-value from the results of the main Cox proportional hazards model. Differences in surgical outcomes were compared using weighted multivariable logistic models. Results: Of the 1924 patients included in the analysis (997 [51.8%] men; median age, 56 [interquartile range extremes (IQRE), 45-65] years), 376 were in the CRS-alone group and 1548 in the CRS-HIPEC group. Patients with CRS alone were older (median age, 60 [IQRE, 48-70] vs 54 [IQRE, 44-63] years), had less lymph node involvement (14 [3.7%] vs 119 [7.7%]), received more preoperative systemic chemotherapy (198 [52.7%] vs 529 [34.2%]), and had higher proportions of high-grade disease (179 [47.6%] vs 492 [31.8%]) and suboptimal cytoreduction residual disease (grade 3, 175 [46.5%] vs 117 [7.6%]). HIPEC was not associated with a higher risk of worse surgical outcomes except with mitomycin, with higher odds of morbidity (1.99; 95% CI, 1.25-3.19; P = .004). HIPEC was associated with a significantly better overall survival in all subsets (adjusted hazard ratios [HRs], 0.60-0.68, with 95% CIs not crossing 1.00). The weighted 5-year overall survival was 57.8% (95% CI, 50.8%-65.7%) vs 46.2% (95% CI, 40.3%-52.8%) for CRS-HIPEC and CRS alone, respectively (weighted HR, 0.65; 95% CI, 0.50-0.83; P < .001; E-value, 2.03). Such prognostic advantage was associated with oxaliplatin plus fluorouracil-leucovorin (HR, 0.42; 95% CI, 0.19-0.93; P = .03) and cisplatin plus mitomycin (HR, 0.57; 95% CI, 0.42-0.78; P = .001) schedules. Conclusions and Relevance: In this cohort study, HIPEC was associated with better overall survival when performed after CRS in PMP, generally without adverse effects on surgical outcomes.

Unusual radiologic presentations of malignant peritoneal mesothelioma.

BACKGROUND: Malignant peritoneal mesothelioma is an unusual disease process characterized radiologically by ascites and infiltration of the peritoneum by multiple small tumor nodules. Both parietal and visceral peritoneum are involved by the multiple malignant tumor nodules. Computed tomography (CT) has been used to identify the anatomic pathology induced by the progression of this malignant process. AIM: To identify and then describe unusual CT images in patients with malignant peritoneal mesothelioma. Recognition of these unusual radiologic findings can cause the radiologist to be suspicious of this rare malignant process. METHODS: In 100 patients who were to undergo definitive treatment of malignant peritoneal mesothelioma, the findings on preoperative CT scans were catalogued. Many of these changes were repeatedly noted on the CT scans. Other pathologic CT images were less common. These unusual radiologic presentations were specially studied in this manuscript. RESULTS: Eight unusual radiologic presentations of malignant peritoneal mesothelioma were selected for study. These unusual findings included a mass occurring within a Spigelian hernia, infiltration of the splenic parenchyma by spherical mesothelioma masses, infiltration of the lower mediastinum by tumor, a mesothelioma mass within a left inguinal canal, enlarged cardiophrenic angle lymph nodes, pleural plaques associated with the progression of malignant peritoneal mesothelioma, splenic notches caused by disease surrounding the spleen, and a mass greater than 5 cm associated with the proximal jejunum and directly adjacent to the anatomic location of the Treitz ligament. CONCLUSION: There are unusual radiologic presentations of malignant peritoneal mesothelioma that are important to recognize in order to accurately diagnose this disease by CT.