Clinicopathological features and genomic profiles of prostate cancer with elevated carbohydrate antigen 19-9.

Abstract

e17003 Background: The elevated carbohydrate antigen 19-9 (CA199) is commonly observed in digestive system tumors, but rarely in prostate cancer (PCa). Due to the rarity and the poor understanding of the special subtype of PCa, the clinicopathological and genomic characteristics and survival outcomes in PCa patients with elevated CA199 in our center were analyzed. Methods: Cases were collected retrospectively from 2012 to 2023 in Sun Yat-sen University Cancer Center. The tumor genomic profiles were analyzed by R (http://www.rproject.org). Kaplan-Meier survival analyses were performed to compare survival outcomes. All statistical analyses were performed using SPSS version 26.0 and GraphPad Prism version 8.0. All analyses were two‐tailed, and the significance level was set at P<0.05. Results: A total of 137 PCa patients with elevated CA199 (>35ng/ml) were identified, with an exclusion of 47 patients with secondary cancers and 40 patients with other diseases that may cause elevated CA199, finally 50 cases (22 with primary and 28 with secondary elevated CA199) were included. The median initial PSA and the median time from diagnosis to CRPC were 102ng/ml and 14 months. Most patients were with a high GS score (GS≥8: 82%) and an advanced stage (M1: 84%). Poorly differentiated adenocarcinoma (22%) was frequently observed. Compared with patients with primary elevated CA199, patients with secondary elevated CA199 had higher levels of CA199 (102ng/ml vs. 78ng/ml, p=0.0456), lower levels of PSA at diagnosis (65ng/ml vs. 132ng/ml, p=0.0131) and higher proportion of poorly differentiated adenocarcinoma (36% vs. 5%, p=0.0138). The level of CA199 in patients with primary elevated CA199 was correlated with the level of CEA (R2=0.2658, p=0.0168), but not with the level of NSE or PSA. At a median follow-up of 31 months, the median OS of the whole group, primary elevated CA199 and secondary elevated CA199 subgroups was 49 months, 31 months and not reached. Secondary elevated CA199 (p=0.0009), abiraterone treatment (p<0.0001) and chemotherapy treatment (p=0.0331) were significant prognostic factors of OS. To study the genomic characteristics of PCa patients with elevated CA199, 29 PCa patients with normal CA199 were included as a control (genomic data available in 13 and 29 cases respectively). Patients with elevated CA199 were more likely to have mutations in castration resistant associated genes (AR, FOXA1, ASXL1, KMT2B, JAK2 and AKT1), malignant progression associated genes (RARA, BLM, PIK3R1) and CA199 metabolism associated gene (ERBB2). Conclusions: PCa with elevated CA199 is highly malignant and with poor prognosis. Intensive treatment with abiraterone and chemotherapy could benefit such patients. Poor pathological differentiation and the gene mutation profile may partly explain the clinical outcome.