Surgical and oncological impact of main pancreatic duct spread in invasive ductal adenocarcinoma: A clinicopathological study of 184 resected cases

Extensive (subtotal) distal pancreatectomy for pancreatic ductal adenocarcinoma: a propensity score matched cohort study of short- and long-term outcomes compared with those of conventional distal pancreatectomy

PURPOSE

Extensive distal pancreatectomy (ExDP) can transect the pancreatic parenchyma more from the right side than conventional distal pancreatectomy (CDP) can. This study aimed to evaluate the short- and long-term outcomes of ExDP for pancreatic ductal adenocarcinoma (PDAC) of the pancreatic body, located adjacent to the portal vein (PV).

METHODS

Medical records of 98 patients who underwent ExDP (n = 15) or CDP (n = 83) for PDAC were retrospectively reviewed. Short- and long-term outcomes of the two groups were compared. Propensity score matched analysis was additionally performed to minimize the impact of treatment allocation bias.

RESULTS

In the total cohort, the CDP group had a significantly higher proportion of pancreatic tail lesions (P < 0.01), higher proportion of males, and larger tumor size. Of the 15 patients who underwent ExDP, 11 could be matched. These differences of patients' characteristics were not observed after matching. Before and after matching, the duration of surgery, blood loss, rate of morbidity including pancreatic fistula, and postoperative course were comparable between the groups. The rate of recurrence and recurrence pattern were also not significantly different between the groups. ExDP for PDAC of the pancreatic body near the PV did not increase local or lymph node recurrence. The disease-free and overall survival did not differ between the groups.

CONCLUSIONS

Surgical and oncological outcomes after ExDP for PDAC were acceptable and comparable to those after CDP. ExDP is a feasible procedure, and could be an option for the treatment of PDAC of the pancreatic body near PV.

Intraductal pancreatic cancer is less responsive than cancer in the stroma to neoadjuvant chemotherapy

Neoadjuvant chemotherapy (NAC) is often the treatment of choice for borderline resectable and locally advanced invasive pancreatic ductal adenocarcinoma (PDAC); however, most cancers only partially respond to therapy. We hypothesized that the location of residual neoplastic cells in resected specimens following NAC could provide a clue as to the mechanisms of resistance. PDAC cells invade the stroma but can also invade back into and spread via the pancreatic ducts, which has been referred to as "cancerization of ducts" (COD). We compared the responsiveness to chemotherapy between PDAC cells in the stroma and PDAC cells in the duct. Pancreatic resections from a total of 174 PDAC patients (NAC, n = 97; immediate surgery, n = 77) were reviewed. On hematoxylin and eosin sections, COD was identified at the same prevalence in both groups (NAC: 50/97 cases, 52%; immediate surgery: 39/77 cases, 51%; p = 0.879, Fisher's exact test). However, using quantitative image analysis of CK19 immunohistochemistry, we found that the proportion of cancer cells that were intraductal was significantly different between the NAC and immediate surgery groups (median; 12.7% vs. 1.99%, p < 0.0001, Mann-Whitney U test). This proportion was highest in patients with marked therapy responses (36.2%) compared with patients with moderate or poor responses (7.21 & 7.91%). In summary, our data suggest that intraductal components in PDAC are less responsive to chemotherapy than the remainder of the tumor, which could have important implications for therapeutic resistance.

Mitochondrial expression of the DNA repair enzyme OGG1 improves the prognosis of pancreatic ductal adenocarcinoma

BACKGROUND/OBJECTIVES

8-Hydroxydeoxyguanosine (8-OHdG) is an indicator of oxidative stress and causes transversion mutations and carcinogenesis. 8-OHdG is excision repaired by 8-OHdG DNA glycosylase 1 (OGG1), which is classified as nuclear and mitochondrial subtypes. We aimed to clarify the role of OGG1 in pancreatic ductal adenocarcinoma (PDAC).

METHODS

Ninety-two patients with PDAC who had undergone surgical resection at multiple institutions were immunohistochemically analyzed. The OGG1 and 8-OHdG expression levels were scored using the Germann Immunoreactive Score. The cutoff values of OGG1, as well as that of 8-OHdG, were determined.

RESULTS

The low nuclear OGG1 expression group (n = 41) showed significantly higher carbohydrate antigen (CA)19-9 (p = 0.026), and higher s-pancreas antigen (SPAN)-1 (p = 0.017) than the high expression group (n = 51). Nuclear OGG1 expression has no effect on the prognosis. The low mitochondrial OGG1 expression group (n = 40) showed higher CA19-9 (p = 0.041), higher SPAN-1 (p = 0.032), and more histological perineural invasion (p = 0.037) than the high expression group (n = 52). The low mitochondrial OGG1 expression group had a significantly shorter recurrence-free survival (p = 0.0080) and overall survival (p = 0.0073) rates. The Cox proportional hazards model revealed that low mitochondrial OGG1 expression is an independent risk factor of the PDAC prognosis. OGG1 expression was negatively correlated with 8-OHdG expression (p = 0.0004), and high 8-OHdG expression shortened the recurrence-free survival of patients with PDAC.

CONCLUSIONS

Low mitochondrial OGG1 expression might aggravate the PDAC prognosis.

Cancerization of the Pancreatic Ducts: Demonstration of a Common and Under-recognized Process Using Immunolabeling of Paired Duct Lesions and Invasive Pancreatic Ductal Adenocarcinoma for p53 and Smad4 Expression

Invasive pancreatic ductal adenocarcinoma (PDAC) can infiltrate back into and spread along preexisting pancreatic ducts and ductules in a process known as cancerization of ducts (COD). Histologically COD can mimic high-grade pancreatic intraepithelial neoplasia (HG-PanIN). We reviewed pancreatic resections from 100 patients with PDAC for the presence or absence of ducts with histologic features of COD. Features supporting COD included adjacent histologically similar invasive PDAC and an abrupt transition between markedly atypical intraductal epithelium and normal duct epithelium or circumferential involvement of a duct. As the TP53 and SMAD4 genes are frequently targeted in invasive PDAC but not HG-PanIN, paired PDAC and histologically suspected COD lesions were immunolabeled with antibodies to the p53 and Smad4 proteins. Suspected COD was identified on hematoxylin and eosin sections in 89 (89%) of the cases. Immunolabeling for p53 and Smad4 was performed in 68 (76%) of 89 cases. p53 was interpretable in 55 cases and all 55 (100%) cases showed concordant labeling between COD and invasive PDAC. There was matched aberrant p53 immunolabeling in 37 (67%) cases including overexpression in 30 (55%) cases and lack of expression in 7 (13%) cases. Smad4 immunolabeling was interpretable in 61 cases and 59 (97%) cases showed concordant labeling between COD and invasive PDAC. Matched loss of Smad4 was seen in 28 (46%) cases. The immunolabeling of invasive PDAC and COD for p53 and Smad4 supports the high prevalence of COD observed on hematoxylin and eosin and highlights the utility of p53 and Smad4 immunolabeling in differentiating COD and HG-PanIN.

Does revision of resection margins based on frozen section improve overall survival following pancreatoduodenectomy for pancreatic ductal adenocarcinoma? A meta-analysis

BACKGROUND

Margin status is the main surgical determinant of long-term outcome in pancreatic cancer. Intraoperative frozen section (IOFS) detects microscopic positive margins at a stage when margin revision is possible. The aim of this study was to determine if IOFS driven-revision of pancreatic resection margin(s) improves overall survival (OS) in pancreatic cancer.

METHODS

A systematic review of major reference databases was undertaken. Patients were divided into 3 groups based on initial FS (FSR0 for negative margin and FSR1 for positive microscopic margin) and final Permanent Section report (PSR0 for negative margin and PSR1 for positive microscopic margin): Group 1 (FSR0 → PSR0), Group 2 (FSR1 → PSR0), and Group 3 (FSR1 → PSR1). Patients in Groups 2 and 3 had surgical revision of the FSR1 margin. Data was meta-analysed.

RESULTS

4 studies included in the final analysis. No difference in OS and incidence of lymph node metastases between Groups 2 and 3 (P = 0.590 and P = 0.410).

CONCLUSIONS

IOFS-based revision of R1 pancreatic resection margin does not improve OS, even when it results in an R0 margin. This suggests that any benefit of margin revision based on FS is over-ridden by markers of more advanced or aggressive disease.