Characteristics of survivors with peritoneal mesothelioma

e16325 Background: Peritoneal mesothelioma (PM) is a rare, fatal malignancy. The aim of the study is to determine the clinical and sociodemographic characteristics associated with long-term survival (LTS). Methods: The 2004 - 2019 National Cancer Database was queried for patients with PM. LTS was defined as having survived at least 5 years following diagnosis. Univariate and multivariate logistic analyses were performed to identify characteristics associated with LTS. A nomogram predicting the likelihood of LTS was developed. Results: 3,636 patients were identified, of which, 18% experienced LTS. The median overall survival (OS) for the entire study population was 17.7 months. The median OS for the LTS cohort was 92 months and 11.7 months for non-long-term survivors (NLTS). In univariate analysis, LTS was more likely to occur in younger (< 50 years), healthy (Charlson-Deyo = 0), female and privately insured patients that traveled farther for care, were treated at an academic or very high-volume center, had epithelial histology, underwent radical surgery and received chemotherapy (p < 0.001). Interestingly, among those who were treated non-operatively, LTS was associated with a longer time-to-chemotherapy (LTS = 50 days, NLTS = 32 days, p < 0.001). Although not statistically significant, among those who received surgery, results suggest that LTS was more likely achieved in those who received hyperthermic intraperitoneal chemotherapy (HIPEC) (p = 0.086). Patients who underwent surgery plus HIPEC experienced the longest median OS (65.9 months) when compared those who underwent surgery plus systemic therapy (38 months) or surgery alone (9.6 months) (p < 0.001). Multivariate logistic regression analysis suggests that age, female gender, and surgical margins are independent predictors of LTS. Based on our nomogram, patients with favorable characteristics resulted in a total score of at least 19 and had an approximate 50% chance of LTS. Conclusions: Age, gender and surgical margins were found to be independent predictors of LTS. Additionally, our nomogram may help predict LTS among patients with PM.