Well-differentiated pancreatic ductal adenocarcinomas measuring ≤ 1 cm exhibit early features of tumor progression: a report of five lesions and a comparative study with advanced lesions

The Time to and Type of Pancreatic Cancer Recurrence after Surgical Resection: Is Prediction Possible?

RATIONALE AND OBJECTIVES

To evaluate factors predicting pancreatic cancer recurrence, and to determine the most common appearance of tumor relapse.

MATERIALS AND METHODS

Ninety patients with recurrent pancreatic cancer were retrospectively included in the study. 74.4% had pancreatic head tumors (group 1) and 25.6% pancreatic body and/or tail tumor (group 2). The tumor localization, operative technique, TNM stage, the R-status, tumor grade, lymphovascular, and perineural invasion were recorded. Location of local tumor recurrence, lymph node recurrence, or organ metastases were analyzed on the basis of follow-up CT imaging.

RESULTS

Mean recurrence time was 17.4 ± 13.2 months. The most common recurrence type was local recurrence (84.4%), followed by lymph node (15.5%), liver (14.4%), and lung metastasis (6.7%). The predominant site of local recurrence in pancreatic head tumors was close to superior mesenteric artery, common hepatic artery, and/or celiac artery (57.4%), followed by area defined by portal vein, inferior vena cava, CA or superior mesenteric artery (31.2%). Patients with pancreatic body and/or tail carcinoma had higher incidence (p = 0.003) of metastatic disease comparing to pancreatic head tumors, while resection margin was the most common type of local tumor recurrence, seen in 46.7% cases versus 8.2% of patients with pancreatic head tumors (p < 0.001).

CONCLUSION

The most common recurrence type in patients with resected pancreatic carcinoma was local recurrence along cardinal arteries. The localization of primary tumor influences the type of tumor relapse and site of local recurrence.

CA19-9 level determines therapeutic modality in pancreatic cancer patients with para-aortic lymph node metastasis

BACKGROUND

In general, para-aortic lymph node (LN16) metastasis has been considered as a contraindication for pancreatic resection. However, some pancreatic cancer patients with LN16 metastasis have been reported to survive for longer than expected after pancreatectomy. The purpose of this study was to determine whether pancreatic cancer patients with LN16 metastasis might benefit from surgery.

METHODS

We retrospectively reviewed 201 consecutive patients with invasive pancreatic ductal adenocarcinoma who underwent surgery at Osaka National Hospital between April 2003 and December 2012. These patients included 22 patients with LN16 metastasis who underwent an extended lymphadenectomy and 25 patients who underwent a palliative surgical biliary and gastric bypass. The clinicopathological data and outcomes were evaluated using univariate and multivariate analyses.

RESULTS

The overall survival of the patients with LN16 metastasis was poorer than that of the LN16-negative patients (P = 0.0014). An overall survival analysis of the LN16-positive patients stratified according to the preoperative CA19-9 level showed a significant difference between patients with a low preoperative CA19-9 level (≤360 U/mL) and those with a high preoperative CA19-9 level (>360 U/mL) (P = 0.0301). No significant difference in overall survival of patients was observed between those with LN16 positivity and those who underwent bypass surgery. However, the overall survival of the LN16-positive patients with a CA19-9 level ≤360 U/mL (n = 11) was significantly higher than that of those who underwent bypass surgery (P = 0.0452).

CONCLUSION

Surgical resection and extended lymphadenectomy remains an option for pancreatic cancer patients with LN16-positivity whose CA19-9 level is ≤360 U/mL.

MicroRNA-181b-5p, ETS1, and the c-Met pathway exacerbate the prognosis of pancreatic ductal adenocarcinoma after radiation therapy

Preoperative chemoradiation therapy (CRT) for pancreatic ductal adenocarcinoma (PDAC) has emerged as a reasonable strategy that shows good prognostic impact. However, after preoperative CRT, resected specimens show remnant tumor cells, which indicate that some tumor cells had acquired or were selected for resistance to CRT. Recently, two oncological mechanisms, the EMT and the presence of CSCs, were reported to be associated with resistance in various cancers. Previous reports showed that HGF could induce EMT in PDAC cells; moreover, the HGF receptor, c‐Met, was identified as a dominant pancreatic CSC marker. However, the clinical significance of c‐Met expression remains unclear. So, we hypothesized that remnant PDAC tissue after CRT might harbor cells with high c‐Met expression, and these cells may exacerbate patients’ prognosis. In the immunohistochemical analysis, we showed that preoperative CRT was significantly associated with high c‐Met expression; moreover, high c‐Met expression was a significant marker of a dismal prognosis. Next, we investigated mechanisms of c‐Met upregulation in PDAC cells. We established GEM‐resistant and radioresistant PDAC cells to analyze the transcriptome involved in c‐Met expression. The microarray data for the established radiation‐resistant PDAC cells indicated miR‐181b‐5p downregulation, which targets ETS1, one of the transcription factors for c‐Met, and it was shown that radiation exposure induced c‐Met expression through ETS1 increase by the suppression of miR‐181b‐5p. These results suggested that targeting these mechanisms may promote the development of a novel multidisciplinary treatment strategy for improving preoperative CRT efficiency.

Clinicopathological Characteristics of Young Patients With Pancreatic Cancer: An Analysis of Data From Pancreatic Cancer Registry of Japan Pancreas Society

OBJECTIVES

The aim of this study was to determine the characteristics of patients with pancreatic ductal adenocarcinoma younger than 40 years.

METHODS

Data from the Japan Pancreas Society's nationwide Pancreatic Cancer Registry were analyzed retrospectively. Clinicopathological characteristics were compared in patients who were grouped according to age, namely, younger than 40 years versus 40 years and older.

RESULTS

Of the 36 145 patients in the database, the younger group included 526 (1.5%) patients. A family history of pancreatic cancer was not more frequent in the younger group. The frequency of Union Internationale Contre le Cancer T4 and M1 were both significantly higher in younger patients, resulting in a higher percentage of patients with Union Internationale Contre le Cancer stage IV. Pancreatectomy was performed less frequently in the younger group, and R0 resection was also less frequent. The overall survival rate was significantly better in the older group, whereas in surgically resected patients, the overall survival and recurrence-free survival rates were not different between the 2 groups.

CONCLUSIONS

Younger patients with pancreatic adenocarcinoma were more often diagnosed at advanced stages, and the overall survival rate was worse than that in older patients. Family genetic background and the prognoses of patients who underwent surgery were similar between the 2 groups.

Re-evaluation of classical prognostic factors in resectable ductal adenocarcinoma of the pancreas

Pancreatic ductal adenocarcinoma carries a poor prognosis with annual deaths almost matching the reported incidence rates. Surgical resection offers the only potential cure. Yet, even among patients that undergo tumor resection, recurrence rates are high and long-term survival is scarce. Various tumor-related factors have been identified as predictors of survival after potentially curative resection. These factors include tumor size, lymph node disease, tumor grade, vascular invasion, perineural invasion and surgical resection margin. This article will re-evaluate the importance of these factors based on recent publications on the topic, with potential implications for treatment and outcome in patients with pancreatic cancer.

Well differentiation and intact Smad4 expression are specific features of groove pancreatic ductal adenocarcinomas

OBJECTIVES

We aimed to select true groove pancreatic ductal adenocarcinomas (GPDACs) and define their specific features.

METHODS

We performed histopathologic and immunohistochemical comparisons of 6 GPDACs with 6 duodenal adenocarcinomas (DACs) and 24 conventional pancreatic ductal adenocarcinomas (cPDACs). Both groups were adjusted to ensure similar mean tumor size.

RESULTS

Representative loupe image showed prominent duodenal invasion and slight pancreatic invasion. Groove pancreatic ductal adenocarcinomas exhibited different mucins and cytokeratin profiles in DACs, but cPDACs and small branch pancreatic ducts had the same profiles. Histopathologic analysis of GPDACs showed a significantly higher incidence of duodenal invasion and well differentiation than cPDACs, although the incidences of lymph node metastasis, angiolymphatic invasion, and neural invasion were similar. Immunohistochemical analysis of GPDACs showed a significantly lower frequency of abnormal Smad4 immunolabeling, and fewer GPDAC samples exhibited abnormal immunolabeling for MUC1, p16, Smad4, and p53 than cPDACs.

CONCLUSIONS

These results suggest that GPDACs arise from small branch pancreatic ducts around accessory pancreatic duct penetrating the groove and duodenum and are distinguishable from DACs. Molecular immunohistochemistry suggests the accumulation of genetic abnormalities during tumor progression is slow in comparison with cPDACs. Thus, the site of PDAC occurrence, such as the border or inner area of the pancreas head, may determine genetic progressivity.