Peritoneal Dissemination in Patients with Recurrence After Post-pleurectomy/decortication for Pleural Mesothelioma.

BACKGROUND: In clinical practice, peritoneal dissemination after curative-intent surgery for pleural mesothelioma occasionally recurs. This study investigated the risk factors and prognosis associated with post-pleurectomy/decortication peritoneal dissemination in pleural mesothelioma, which are rarely reported. METHODS: This retrospective review included 160 patients who experienced recurrence after pleurectomy/decortication for pleural mesothelioma between January 2011 and December 2021. Patients with recurrence were classified according to the initial recurrence pattern. The P group experienced recurrence with peritoneal dissemination, and the non-P group experienced recurrence without peritoneal dissemination. The analysis determined the risk factors for peritoneal dissemination using multivariable logistic regression analysis. Survival was analyzed using the Kaplan-Meier method and the log-rank test. RESULTS: Of the 160 patients, 20 (12.5%) exhibited peritoneal dissemination and were assigned to the P group, whereas 140 (87.5%) had recurrence without peritoneal dissemination and were assigned to the non-P group. Multivariable logistic regression analysis showed that diaphragm reconstruction (odds ratio [OR], 2.8; 95% confidence interval [CI], 1.0-8.0; p = 0.048) and female sex (OR, 3.7; 95% CI 1.26-10.8; p = 0.017) were associated with the P group. Post-recurrence survival was worse in the P group than in the non-P group (1-year post-recurrence survival: 22.2% vs. 65.3%; median: 6.7 months vs. 19.4 months; p = 0.0013). CONCLUSIONS: Peritoneal dissemination occurred in approximately one of every eight patients with recurrence after pleurectomy/decortication for pleural mesothelioma, and the incidence was significantly higher among females and patients undergoing diaphragm reconstruction. Moreover, postoperative recurrence of peritoneal dissemination was associated with a poor prognosis.

Comparison of FDG-PET/CT and CT for evaluation of tumor response to nivolumab plus ipilimumab combination therapy and prognosis prediction in patients with unresectable malignant pleural mesothelioma.

OBJECTIVES: Results for malignant pleural mesothelioma (MPM) patients following first-line treatment with nivolumab plus ipilimumab obtained with immunotherapy-modified PERCIST (imPERCIST), shown by [18F]fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT), and modified RECIST (mRECIST), shown by CT, were compared for response evaluation and prognosis prediction. RESULTS: imPERCIST indicated nine progressive metabolic disease (PMD), eight stable metabolic disease (SMD), four partial metabolic response (PMR), and five complete metabolic response (CMR) cases. mRECIST showed nine with progressive disease (PD), nine stable disease (SD), seven partial response (PR), and one complete response (CR). Although high concordance was noted (κ = 0.827), imPERCIST correctly judged a greater percentage with CMR (15.4%). Following a median 10.0 months, 15 patients showed progression and eight died from MPM. With both, progression-free survival (PFS) and overall survival (OS) were significantly longer in patients without progression (CMR/PMR/SMD, CR/PR/SD, respectively) as compared to PMD/PD patients (imPERCIST p < 0.0001 and p = 0.015, respectively; mRECIST p < 0.0001 and p = 0.015, respectively). METHODS: Twenty-six patients (23 males, 3 females; median 73.5 years) with histologically proven MPM and no curative surgery received nivolumab plus ipilimumab combination therapy. FDG-PET/CT and diagnostic CT scanning at the baseline, and after 2-4 cycles (2 in three, 3 in 17, 4 in six patients) were performed. Therapeutic response findings evaluated using imPERCIST and mRECIST were compared. PFS and OS analyses were done using log-rank and Cox methods. CONCLUSION: For unresectable MPM patient examinations, FDG-PET and CT provide accurate findings for evaluating tumor response and also prognosis prediction following first-line nivolumab plus ipilimumab immunotherapy (approximately three cycles).

Impact of Operation on Disease Progression and Survival of Patients With Pleural Mesothelioma.

BACKGROUND: The effects of surgery on the survival of patients with pleural mesothelioma remain poorly understood. We compared the therapeutic outcomes of patients receiving neoadjuvant chemotherapy, followed by surgery or refusing surgery, for pleural mesothelioma. METHODS: This retrospective study included consecutive patients who were eligible for curative-intent surgery after 3 cycles of neoadjuvant chemotherapy with platinum plus pemetrexed at our hospital during January 2011 to December 2021. Patients were divided into 2 groups. The surgery group comprised patients who underwent curative-intent surgery for pleural mesothelioma. The refusal-of-surgery group comprised patients who were medically eligible for surgery but refused to consent to surgery. Overall survival and progression-free survival were calculated using the Kaplan-Meier method with the generalized Wilcoxon test. RESULTS: Of the 296 eligible patients for the study, 272 underwent surgery and 24 refused surgery. During the surgery, 204 patients (75.0%), 43 (15.8%), and 25 (9.2%) underwent pleurectomy/decortication, extrapleural pneumonectomy, and exploratory thoracotomy, respectively. The median follow-up length was 28.4 months. The median overall survival periods were 40.7 months (95% CI, 32.2-45.6 months) for surgery and 23.6 months (95% CI, 15.2-43.0 months) for refusal of surgery (P = .03). The median progression-free survival periods were 20.2 months (95% CI, 17.0-22.5 months) for surgery and 12.9 months (95% CI, 8.3-16.8 months) for refusal of surgery (P < .001). CONCLUSIONS: Overall survival and progression-free survival were significantly better in surgery than in refusal of surgery. Surgery may improve the survival outcomes of patients with pleural mesothelioma.