Tumor-stroma ratio as a new prognosticator for pseudomyxoma peritonei: a comprehensive clinicopathological and immunohistochemical study

Background As a rare clinical tumor syndrome with an indolent clinical course and lack of pathognomonic symptoms, pseudomyxoma peritonei (PMP) is usually diagnosed at an advanced stage. In-depth pathological analysis is essential to assess tumor biological behaviors, assist treatment decision, and predict the clinical prognosis of PMP. The tumor-stroma ratio (TSR) is a promising prognostic parameter based on the tumor and stroma. This study explored the relationship between TSR and the pathological characteristics and prognosis of PMP. Methods PMP patients with complete data who underwent cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy were enrolled. The TSR of postoperative pathological images was quantitatively analyzed by Image-Pro Plus. Then the relationship between TSR and the clinicopathological characteristics, immunohistochemical characteristics and prognosis of PMP was analyzed. Results Among the 50 PMP patients included, there were 27 males (54.0%) and 23 females (46.0%), with a median age of 55 (range: 31–76) years. 25 (50.0%) patients were diagnosed with low-grade PMP (LG-PMP), and 25 (50.0%) were diagnosed with high-grade PMP (HG-PMP). There were 4 (8.0%) patients with vascular tumor emboli, 3 (6.0%) patients with nerve invasion, and 5 (10.0%) patients with lymph node metastasis. The immunohistochemical results showed that the Ki67 label index was < 25% in 18 cases (36.0%), 25 - 50% in 18 cases (36.0%) and > 50% in 14 cases (28.0%). The range of TSR was 2 - 24% (median: 8%). The cutoff value of TSR was 10% based on the receiver operating characteristic (ROC) curve and X-Tile analysis. There were 31 (62.0%) cases with TSR < 10% and 19 (38.0%) cases with TSR ≥ 10%. The TSR was closely related to histopathological type (P < 0.001) and Ki67 label index (P < 0.001). Univariate analysis showed that preoperative carcinoembryonic antigen (CEA), preoperative carbohydrate antigen 19–9, pathological type, vascular tumor emboli and TSR influenced the prognosis of PMP patients (P < 0.05). Multivariate analysis showed that preoperative CEA, vascular tumor emboli and the TSR were independent prognostic factors. Conclusions The TSR could be a new independent prognosticator for PMP.

Tumor-stroma Ratio as a New Prognosticator for Pseudomyxoma Peritonei: a Comprehensive Clinicopathological and Immunohistochemical Study

Background: As a rare clinical tumor syndrome, pseudomyxoma peritonei (PMP) is usually diagnosed at an advanced stage. In-depth pathological analysis is essential to assessing tumor biological behaviors, assisting treatment decision, and predicting clinical prognosis of PMP. Tumor-stroma ratio (TSR) is a promising prognostic parameter based on tumor and stroma. This study was to explore the relationship between TSR with pathological characteristics and prognosis of PMP.Methods: PMP patients with complete data who underwent last cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy were collected. The TSR of postoperative pathological images was quantitatively analyzed by Image-Pro Plus. Then the relationship between TSR with clinicopathological characteristics, immunohistochemical characteristics and prognosis of PMP was analyzed.Results: Among the 50 PMP patients included, there were 27 males (54.0%) and 23 females (46.0%), with a median age of 55 (31 - 76) years. The patients with histopathological types of disseminated peritoneal adenomucinosis (DPAM) and peritoneal mucinous carcinomatosis (PMCA) were both 25 (50.0%), 4 cases (8.0%) with vascular tumor emboli, 3 cases (6.0%) with nerve invasion, and 5 cases (10.0%) with lymph node metastasis. Immunohistochemical results showed that Ki67 label index was < 25% in 18 cases (36.0%) and ≥ 25% in 32 cases (64.0%). The range of TSR was 2% - 24% (median: 8%). The cutoff value of TSR was 10% based on receiver operating characteristic (ROC) curve. There were 31 cases with TSR < 10% while 19 cases with TSR ≥ 10%. It showed that TSR was closely related to histopathological types (P < 0.001) and Ki67 label index (P < 0.001). Univariate analysis showed that preoperative carcinoembryonic antigen (CEA), preoperative carbohydrate antigen (CA) 19-9, pathological types, vascular tumor emboli and TSR influenced prognosis of PMP patients (P < 0.05). Multivariate analysis showed preoperative CEA, vascular tumor emboli and TSR were independent prognostic factors.Conclusion: TSR could be a new independent prognosticator for PMP.