Preoperative maximum standardized uptake value and carbohydrate antigen 19–9 were independent predictors of pathological stages and overall survival in Chinese patients with pancreatic duct adenocarcinoma

Pancreatic duct adenocarcinoma (PDAC) has not only an increasing incidence in many countries, but also the worst prognosis in digestive tract malignancies [1]. In the United States, it is the fourth most common cause of cancer-related mortality and has a 5-year survival rate of less than 5% [1]. As shown in Cancer Statistics in China (2015), its new cases were estimated to be 90.1 thousands and new deaths were estimated to be 79.4 thousands in China. Pancreaticoduodenectomy (PD) is an effective treatment for patients with PDAC and achieves a 5-year survival rate of approximately 15 to 40% [2]. However, regardless of clinically unresectable PDAC (85–90%), these patients with PDAC still have poor prognosis after PD, with a median survival of 11–19 months [3‐5]. Early and individualized operative strategy and perioperative management have reduced perioperative mortality of patients with PDAC after PD to < 5% [6, 7]. Preoperative variables would be of great significance to stratify the patients with PDAC and predict the prognosis of patients after PD, and thus promote the early and individualized operative strategy and perioperative management [8].

The most widely applied ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT)-derived variable designed to measure tracer accumulation is the maximum standardized uptake value (SUVmax), which quantifies the rate of glucose metabolic uptake in tumor cells [9]. Recent studies have considered the SUVmax to be beneficial as prognostic factors in patients with PDAC [10]. However, there are still limited studies regarding the prognostic value of SUVmax in Chinese patients with PDAC after PD. Meanwhile, carbohydrate antigen 19–9 (CA19–9), a sialyated Lewis blood group antigen, is expressed in pancreatic ductal cells [11]. Preoperative CA19–9 levels have been shown to be associated with a significant improvement in postoperative survival in patients with PDAC [12]. However, only a small number of studies have investigated the potential role of preoperative CA19–9 levels as a prognostic variable in Chinese patients with PDAC after PD [13]. Purpose of the current study was to analyze whether preoperative SUVmax and CA19–9 levels might provide meaningful prognostic information in Chinese patients with PDAC after PD.

PDAC has a growing trend of incidence and accounts for 1–2% of malignant cancers [1, 2]. Although more patients with PDAC have received the PD, they have not obtained significant improved OS [3‐5]. Early and individualized operative strategy and perioperative management have the potential to improve the prognosis of patients with PDAC after PD [6, 7]. It results in a greater focus of preoperative variables predicting the OS [8]. The results from the current study confirmed that preoperative SUVmax and CA19–9 levels were independently prognostic predictors of patients with PDAC after PD.

¹⁸F-FDG PET/CT is a high-tech imaging method not only accurately indicating anatomical image but also effectively displaying functional metabolism [15]. ¹⁸F-FDG has become extensively applied as a tracer of PET/CT in clinical imaging of PDAC [16]. As PDAC cells progress and anaerobic glycolysis increases, ¹⁸F-FDG is taken up more by PDAC cells, converted into 6-P-¹⁸F-FDG, and stored in PDAC cells. Previous studies have shown that SUVmax plays a significant role in not only the diagnosis, but also staging and prognosis in patients with PDAC [17, 18]. However, conflicting results have been published regarding the prognostic value of SUVmax [19‐21]. Moreover, previous studies exploring the value of SUVmax for staging and prognosis have been limited, especially in Chinese patients with PDAC [22]. The current study indicated that SUVmax was a prognostic predictor of OS, suggesting that ¹⁸F-FDG-PET/CT might serve as an important imaging method that applied to stratify the patient with PDAC and predict the prognosis of patients after PD.

As one cancer marker often applied to screen the PDAC, CA19–9 is the mucoprotein present in pancreatic, biliary, gastric and intestinal epithelium cells [23]. On the one hand, PDAC cells grow up, invade and injure the normal pancreatic and biliary cells, leading to their release of CA19–9; on the other hand, PDAC cells release the CA19–9 by themselves as PDAC grows up. Previous studies have investigated the potential prognostic value of preoperative CA19–9 levels in patients with PDAC [13] However, preoperative variables that may play a predictive role in patients with PDAC are poorly understood in previous studies, especially in Chinese patients. The current study proved that preoperative CA19–9 levels were associated with significant reduced OS and more poor differentiation following PDAC. These findings supported that preoperative CA19–9 levels were not only indicative of tumour burden, but also that preoperative CA19–9 levels might act as a marker of biological aggressiveness [24].

The current study demonstrated that preoperative SUVmax and CA19–9 levels independently predicted pathological stages and OS of patients with PDAC after PD. These preoperative variables might have significant prognostic implication in patients with PDAC after PD. Patients with abnormal SUVmax and CA19–9 levels should be paid special attention to in operative strategy and perioperative management.