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

Abstract

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.

A nomogram prediction model of pseudomyxoma peritonei established based on new prognostic factors of HE stained pathological images analysis

“…In‐depth study of TNs and TCs can reveal more useful information about tumor development. Our previous study showed that the ratio of tumor/stroma area had a significant impact on the prognosis, suggesting the clinical value of TNs area 35 . Choudry et al 19 .…”

“…Our previous study showed that the ratio of tumor/stroma area had a significant impact on the prognosis, suggesting the clinical value of TNs area. 35 Choudry et al. 19 and Horvath et al.…”

“…Our previous study showed that the ratio of tumor/stroma area had a significant impact on the prognosis, suggesting the clinical value of TNs area. 35 Choudry et al 19 and Horvath et al 36 found that PMP patients with medium or high TCs density had a higher risk of disease progression. Bhatt et al 18 found that the cytological morphology of TCs also affected the prognosis of PMP patients.…”