Impact of Lymph Node Micrometastasis in Patients with Pancreatic Head Cancer

Clinical Applications of Classical and Novel Biological Markers of Pancreatic Cancer

The incidence and prevalence of pancreatic adenocarcinoma have increased in recent years. Pancreatic cancer is the seventh leading cause of cancer death, but it is projected to become the second leading cause of cancer-related mortality by 2040. Most patients are diagnosed in an advanced stage of the disease, with very limited 5-year survival. The discovery of different tissue markers has elucidated the underlying pathophysiology of pancreatic adenocarcinoma and allowed stratification of patient risk at different stages and assessment of tumour recurrence. Due to the invasive capacity of this tumour and the absence of screening markers, new immunohistochemical and serological markers may be used as prognostic markers for recurrence and in the study of possible new therapeutic targets because the survival of these patients is low in most cases. The present article reviews the currently used main histopathological and serological markers and discusses the main characteristics of markers under development.

Preoperative risk factors for para-aortic lymph node positivity in pancreatic cancer

PURPOSE

This study aimed to identify the preoperative risk factors for para-aortic lymph node (PALN) positivity, including micrometastasis, in pancreatic cancer.

METHODS

Medical records of patients with pancreatic cancer who underwent curative resection were retrospectively reviewed, and the relationships between preoperative risk factors and PALN positivity were identified. Clinicopathological and prognostic factors for overall survival were analyzed. Micrometastasis was investigated by immunohistochemistry.

RESULTS

400 patients were enrolled. PALN positivity by hematoxylin and eosin staining, micrometastasis, and negative were found in 46 (11%), 32 (8%), and 322 (81%) patients, respectively. The median overall survival times of patients with PALN positivity, including micrometastasis, was 22.5 months. Multivariate logistic regression identified borderline or locally advanced status (p=0.037), elevated preoperative carbohydrate antigen (CA) 19-9 level (p<0.001), larger tumor size ≥30 mm (p=0.001) and larger PALN size ≥10 mm (p=0.019) as independent preoperative risk factors of PALN positivity. Multivariate overall survival analysis demonstrated borderline or locally advanced status (p=0.013), elevated preoperative CA19-9 level (p<0.001) and PALN positivity (p=0.048) were independent poor prognostic factors.

CONCLUSIONS

Borderline or locally advanced status, elevated preoperative CA19-9 level, and larger tumor and PALN size were risk factors for PALN positivity, and thus, they may contribute to the optimization of preoperative treatments for patients with potential PALN positivity.

Predictive factors for long-term survival after surgery for pancreatic ductal adenocarcinoma: Making a case for standardized reporting of the resection margin using certified cancer center data

Factors for overall survival after pancreatic ductal adenocarcinoma (PDAC) seem to be nodal status, chemotherapy administration, UICC staging, and resection margin. However, there is no consensus on the definition for tumor free resection margin. Therefore, univariate OS as well as multivariate long-term survival using cancer center data was analyzed with regards to two different resection margin definitions. Ninety-five patients met inclusion criteria (pancreatic head PDAC, R0/R1, no 30 days mortality). OS was analyzed in univariate analysis with respect to R-status, CRM (circumferential resection margin; positive: ≤1mm; negative: >1mm), nodal status, and chemotherapy administration. Long-term survival >36 months was modelled using multivariate logistic regression instead of Cox regression because the distribution function of the dependent data violated the requirements for the application of this test. Significant differences in OS were found regarding the R status (Median OS and 95%CI for R0: 29.8 months, 22.3–37.4; R1: 15.9 months, 9.2–22.7; p = 0.005), nodal status (pN0 = 34.7, 10.4–59.0; pN1 = 17.1, 11.5–22.8; p = 0.003), and chemotherapy (with CTx: 26.7, 20.4–33.0; without CTx: 9.7, 5.2–14.1; p < .001). OS according to CRM status differed on a clinically relevant level by about 12 months (CRM positive: 17.2 months, 11.5–23.0; CRM negative: 29.8 months, 18.6–41.1; p = 0.126). A multivariate model containing chemotherapy, nodal status, and CRM explained long-term survival (p = 0.008; correct prediction >70%). Chemotherapy, nodal status and resection margin according to UICC R status are univariate factors for OS after PDAC. In contrast, long-term survival seems to depend on wider resection margins than those used in UICC R classification. Therefore, standardized histopathological reporting (including resection margin size) should be agreed upon.

Development and validation of novel nomograms for predicting the survival of patients after surgical resection of pancreatic ductal adenocarcinoma

Background/Aims

Pancreatic ductal adenocarcinoma (PDAC) is associated with high mortality, even after surgical resection. The existing predictive models for survival have limitations. This study aimed to develop better nomograms for predicting overall survival (OS) and cancer‐specific survival (CSS) in PDAC patients after surgery.

Methods

A total of 6323 PDAC patients were retrospectively recruited from the Surveillance, Epidemiology, and End Results (SEER) database and randomly allocated into training, validation, and test cohorts. Multivariate Cox regression analysis was conducted to identify significant independent factors for OS and CSS, which were used for construction of nomograms. The performance was evaluated, validated, and compared with that of the 8th edition AJCC staging system.

Results

Ten independent factors were significantly correlated with OS and CSS. The 1‐, 3‐, and 5‐year OS rates were 40%, 20%, and 15%, and 1‐, 3‐, and 5‐year CSS rates were 45%, 24%, and 19%, respectively. The nomograms were calibrated well, with c‐indexes of 0.640 for OS and 0.643 for CSS, respectively. Notably, relative to the 8th edition AJCC staging system, the nomograms were able to stratify each AJCC stage into three prognostic subgroups for more robust risk stratification. Furthermore, the nomograms achieved significant clinical validity, exhibiting wide threshold probabilities and high net benefit. Performance assessment also showed high predictive accuracy and reliability.

Conclusions

The predictive ability and reliability of the established nomograms have been validated, and therefore, these nomograms hold potential as novel approaches to predicting survival and assessing survival risks for PDAC patients after surgery.

Prognostic Significance of Lymph Node Metastasis and Micrometastasis Along the Left Side of Superior Mesenteric Artery in Pancreatic Head Cancer

BACKGROUNDS AND OBJECTIVES

Although metastasis in lymph nodes along the left side of superior mesenteric artery (SMA-LNs-lt) is sometimes found, survival benefit of SMA-LN-lt dissection for pancreatic head cancer is still unclear. The purpose of this study is to evaluate the prognostic significance of SMA-LN-lt metastasis and micrometastasis.

METHODS

A total of 166 patients with pancreatic head cancer who underwent pancreatectomy with lymphadenectomy including SMA-LNs-lt between 2002 and 2017 were reviewed retrospectively. Micrometastasis was evaluated by immunohistochemistry.

RESULTS

Twenty patients (12%) had SMA-LN-lt metastasis detected by hematoxylin and eosin (HE) staining, and eight patients (5%) had micrometastasis. Patients with SMA-LN-lt HE-positive or micrometastasis group experienced significantly shorter overall survival (OS) than those without (p = .015). In multivariate analysis, SMA-LN-lt HE-positive or micrometastasis (p = .034), portal vein resection (p = .002), histologic grade 2/3 (p = .046), LN metastasis (p = .002), and lack of adjuvant chemotherapy (p < .001) were independent risk factors. Within a subset of SMA-LN-lt HE-positive or micrometastasis group, lack of adjuvant chemotherapy (p = .003) was the independent poor prognostic factor.

CONCLUSIONS

In pancreatic head cancer, the rate of SMA-LN-lt HE-positive and micrometastasis was found in 12% and 5%, respectively. Adjuvant chemotherapy may contribute to improvement of prognosis in patients with LN metastasis including SMA-LN-lt metastasis and micrometastasis.

Pathomorphological features of metastatic lymph nodes as predictors of postoperative prognosis in pancreatic cancer

To investigate the pathological features of metastatic lymph nodes (LN) in pancreatic ductal adenocarcinoma (PDAC) and to determine factors with prognostic implications.Metastatic LN status is a proven significant factor for predicting postoperative prognosis in pancreatic cancer patients. However, the effective prognostic criteria regarding metastatic LNs for such disease remain unknown.We retrospectively reviewed 98 patients with R0/1 resection for PDAC. All metastatic LNs were evaluated for the pathomorphological features of metastasis and analyzed in terms of postoperative outcomes. Various morphological patterns of metastasis were assessed in 440 positive LNs and then classified into 4 groups: common type, direct type (continuously invaded by the main tumor), scatter type (multiple tumor clusters among the normal LN tissues), and isolated tumor cell (ITC).The pathological stage was defined as stage IIA in 10% and IIB in 90% patients. Common-type metastasis was noted in 55% positive LNs of 75% node-positive patients; direct type in 36% LNs of 69% patients; scatter type in 5% LNs of 14% patients; and ITCs in 5% LNs of 18% patients. Significant difference was noted only in recurrence-free survival (RFS) but not in overall survival (OS) in the common-type; only in OS but not in RFS for the scatter type; and neither in RFS nor OS for both direct type and ITC. Multivariate analysis revealed that only LN ratio and curability were independent predictive factors of poor.The tumor distribution patterns in metastatic LNs are the postoperative prognostic factors in pancreatic cancer.

Dilemmas for the pathologist in the oncologic assessment of pancreatoduodenectomy specimens : An overview of different grossing approaches and the relevance of the histopathological characteristics in the oncologic assessment of pancreatoduodenectomy specimens

A pancreatoduodenectomy specimen is complex, and there is much debate on how it is best approached by the pathologist. In this review, we provide an overview of topics relevant for current clinical practice in terms of gross dissection, and macro- and microscopic assessment of the pancreatoduodenectomy specimen with a suspicion of suspected pancreatic cancer. Tumor origin, tumor size, degree of differentiation, lymph node status, and resection margin status are universally accepted as prognostic for survival. However, different guidelines diverge on important issues, such as the diagnostic criteria for evaluating the completeness of resection. The macroscopic assessment of the site of origin in periampullary tumors and cystic lesions is influenced by the grossing method. Bi-sectioning of the head of the pancreas may offer an advantage in this respect, as this method allows for optimal visualization of the periampullary area. However, a head-to-head comparison of the assessment of clinically relevant parameters, using axial slicing versus bi-sectioning, is not available yet and the gold standard to compare both techniques prospectively might be subject of debate. Further studies are required to validate the various dissection protocols used for pancreatoduodenectomy specimens and their specific value in the assessment of pathological parameters relevant for prognosis.

Systematic review of the clinical significance of lymph node micrometastases of pancreatic adenocarcinoma following surgical resection

OBJECTIVES

The aim of this study is to perform a systematic review of the clinical impact of lymph node micrometastasis in pancreatic adenocarcinoma following surgical resection.

METHODS

A systematic review was conducted and published literature were searched using "pancreas or pancreatic" and "cancer or carcinoma or neoplasm", and "micrometastasis or micrometastses" in the PubMed, EMBAE, and Web of Science.

RESULTS

Thirteen publications with 726 patients and 3701 lymph nodes were included in this systematic review. The detection method was immunohistochemical stains or polymerase chain reaction. The pooled proportion of patients with positive lymph node micrometastasis was 43.1% (95% Confidence interval (CI) 0.254-0.628). The pooled proportion of positive lymph node micrometastasis (number of positive lymph node micrometastasis/total number of lymph nodes examined) was 10.8% (95% CI 4.8-22.6). Among the conventional H &E negative patients, the reported 5-year survival rates of the patients without lymph node micrometastases vs. those with lymph node micrometastases in the ranged from 50% to 61% and from 0% to 36%, respectively Patients with lymph node micrometastasis showed poorer survival (Hazard ratio 4.29, 95% CI 1.27-14.41).

CONCLUSIONS

The presence of lymph node micrometastasis is associated with poorer survival. Lymph node micrometastasis is applicable to stratify the risk of recurrence and the need for adjuvant therapy of post-resection patients with pancreatic adenocarcinoma in the conventional H & E lymph node negative patients.

Prognostic Impact of Para-Aortic Lymph Node Micrometastasis in Pancreatic Ductal Adenocarcinoma

BACKGROUND

It is still unclear whether micrometastasis of para-aortic lymph nodes (PALNs) in pancreatic ductal adenocarcinoma (PDAC) is tantamount to PALN metastasis detected by hematoxylin and eosin (HE) staining.

METHODS

A total of 242 patients with PDAC who underwent radical pancreatectomy with PALN dissection were eligible for this study. Micrometastasis in PALNs was evaluated by CAM 5.2 immunohistochemistry. The relationship between PALN status and overall survival (OS) was analyzed.

RESULTS

Of the 242 enrolled patients, 25 (10 %) had PALN metastasis detected by HE (PALN HE-positive), and 21 (9 %) had PALN micrometastasis not detected by HE but identified by CAM 5.2 immunohistochemistry. Univariate analysis revealed that patients with PALN micrometastasis (p = .004) and PALN HE positivity (p = .003) had a significantly shorter OS than those without PALN metastasis, whereas no significant difference was observed between the two former groups (p = .874). In multivariate analysis, lack of adjuvant chemotherapy (hazard ratio [HR] 2.43, p < .001), PALN micrometastasis (HR 1.89; p = .046), and PALN HE-positivity (HR 1.89, p = .023) were identified as independent risk factors for poor prognosis. Within a subset of 46 patients with PALN HE-positivity or micrometastasis, lack of adjuvant chemotherapy was independently associated with poor OS (HR 2.58. p = .029).

CONCLUSIONS

The prognosis of patients with PALN micrometastasis was extremely poor as well as HE-positive PALNs. However, postoperative adjuvant chemotherapy may contribute to improving the prognosis of PDAC patients with PALN metastasis.

Distribution and clinical significance of tumour-associated macrophages in pancreatic ductal adenocarcinoma: a retrospective analysis in China

BACKGROUND

We aimed to characterize the localization and prognostic significance of tumour-associated macrophages (tams) in pancreatic ductal adenocarcinoma (pdac).

METHODS

Tumour specimens from 70 patients with pdac and inflammatory specimens from 13 patients with chronic pancreatitis were collected and analyzed for tam and M2 macrophage counts by immunohistochemistry. Correlations between tam distributions and clinicopathologic features were determined.

RESULTS

Immunohistochemical analysis showed that tam and M2 macrophage counts were higher in tissues from pdac than from chronic pancreatitis. The tams and M2 macrophages both infiltrated more into peritumour. Both macrophage types were positively associated with lymph node metastasis (p = 0.041 for tams in peritumour, p = 0.013 for M2 macrophages in introtumour, p = 0.006 for M2 macrophage in peritumour). In addition, abdominal pain was significantly more frequent in pdac patients with a greater tams count. The survival rate was much lower in patients having high infiltration by M2 macrophages than in those having low infiltration.

CONCLUSIONS

The tam count might be associated with neural invasion in pdac, and M2 macrophages might play an important role in lymph node metastasis. Higher counts of either macrophage type were associated with increased risk of lymph node metastasis, and the M2 macrophage count could potentially be a marker for evaluating prognosis.

Para-aortic lymph node sampling in pancreatic head adenocarcinoma

BACKGROUND

The significance of positive para-aortic nodes in patients with resectable pancreatic carcinoma is unclear. This study sought to evaluate the accuracy of intraoperative detection and prognostic significance of these lymph nodes in patients with resected adenocarcinoma of the pancreatic head.

METHODS

From 2000 to 2010, para-aortic node sampling was performed prospectively in all patients before pancreatoduodenectomy. Frozen sections were created and nodes categorized as positive or negative for metastases. Surgeons were blinded to the frozen-section results. This was followed by standard histopathological assessment of corresponding paraffin-embedded, haematoxylin and eosin-stained material. Nodes considered uninvolved by this analysis were examined immunohistochemically for micrometastases.

RESULTS

A total of 111 consecutive patients were included, with a median follow-up of 20·8 (range 1·5-126) months. The 1-, 2- and 5-year overall survival (OS) and disease-free survival (DFS) rates were 73·6, 54·0 and 24·7 per cent, and 51·8, 28·1 and 18·8 per cent respectively. Para-aortic node involvement was always associated with peripancreatic lymph node metastasis, and was detected by frozen-section analysis in 12 patients and by haematoxylin and eosin staining in 17. Sensitivity and specificity of frozen-section examination for detecting para-aortic lymph node metastases were 71 and 100 per cent respectively. Median OS for patients with and without para-aortic node involvement on frozen-section analysis was 9·7 versus 28·5 months respectively (P = 0·012), and 15·7 versus 27·2 months (P = 0·050) when assessed by haematoxylin and eosin staining. Median DFS for patients with and without para-aortic node involvement on frozen-section examination was 5·6 versus 12·9 months respectively (P = 0·041), and 8·4 versus 12·9 months (P = 0·038) for haematoxylin and eosin analysis. The presence of micrometastases in para-aortic nodes was not significantly associated with altered OS or DFS.

CONCLUSION

Para-aortic node sampling with frozen-section examination detects distant lymphatic involvement reliably. It should be performed systematically. When metastases are found, they should be considered a contraindication to pancreatic resection.

Clinical necessity of the immunohistochemical reassessment of para-aortic lymph nodes in resected pancreatic ductal adenocarcinoma

Para-aortic lymph node (PALN) metastasis is widely regarded as a systemic disease in cancer. Undetected PALN micrometastases during routine hematoxylin and eosin (HE) staining may be a cause of poor prognosis following a potentially curative pancreatectomy for pancreatic cancer. In the present study, paraffin-embedded PALN tissue blocks from 99 patients who underwent a pancreatectomy were re-evaluated by immunohistochemical staining using cytokeratin (CK)-19. Patients with PALN metastasis were summarized according to the clinicopathological data. A total of 484 PALNs (median, 4.9 nodes per patient; range, 1–19) were evaluated. PALN metastases were revealed in eight patients (8.1%) by routine HE staining of frozen section biopsies and in one patient (1.0%) by HE staining of a permanent section. Only one patient (1.0%) demonstrated micrometastasis by IHC; this patient did not display any adverse pathological characteristics and had a relatively favorable survival period of 41 months. The present study concluded that an additional reassessment for micrometastasis in PALNs using CK-19 immunohistochemistry (IHC) is not a viable method for determining the survival outcome. A careful examination of a frozen section biopsy is sufficient for attempting curative surgery.

Is minimal residual lymph node disease in papillary thyroid cancer of prognostic impact? An analysis of the epithelial cell adhesion molecule EpCAM in lymph nodes of 40 pN0 patients

This study was aimed to assess the extend of nodal microdissemination in patients with pN0 papillary thyroid carcinoma (PTC) using immunohistochemical analysis. In early stage PTC both, systematic lymphadenectomy as well as radio iodine treatment, aimed to eliminate occult nodal tumor involvement, are under controversial debate, since little is known about the extend of lymphatic microdissemination in these patients. Formalin embedded samples of the resected lymph nodes were systematically screened for the presence of disseminated tumor cells using immunohistochemistry (monoclonal antibody Ber-EP4). Clinical and histopathological parameters as well as the post-operative course were recorded. Survival data were analysed by the Kaplan-Meier method and the log rank test. Overall 321 lymph nodes of 40 patients were screened immunohistochemically. In 12.5% of the patients disseminated occult tumor cells were diagnosed. In addition to tumor resection 90% of the patients underwent adjuvant radio-iodine treatment. The mean observation period in our collective was 72 months. The detection of disseminated tumor cells did not correlate with clinicopathologic risk parameters and did not have significant influence on the prognosis of these patients. Immunohistochemical analysis enables the detection of disseminated tumor cells in patients with pN0 PTC. This finding seems to support the application of adjuvant radio iodine, even in early tumor stages.

Vascular invasion in pancreatic cancer: tumor biology or tumor topography?

BACKGROUND

Although vascular resection in pancreatic adenocarcinoma increases the resection rate, involvement of the vascular structures frequently is assumed to be associated with a more aggressive tumor biology and tumor cell dissemination. Our study's aim was to assess the correlation of vascular tumor involvement with adverse, clinicopathologic prognosticators and with the extent of tumor cell dissemination.

METHODS

We studied 108 patients who had undergone pancreatic resection, of whom 39 underwent vascular resection. Clinical parameters and the postoperative course were recorded. Formalin-embedded lymph node samples as well as bone marrow aspirates were screened immunohistochemically for disseminated tumor cells. Univariate and multivariate analyses were performed using the log-rank test and the Cox proportional-hazard models.

RESULTS

Overall, 2,388 lymph nodes and bone marrow aspirates from 49 matched patients were screened immunohistochemically. Fully 50% of the patients had disseminated tumor cells in lymph nodes and 27% in bone marrow. The mean observation period in cohort was 28 months. Vascular resection did not correlate with prognostically relevant parameters. Disseminated tumor cells in lymph nodes were associated with a decrease in relapse-free survival (P = .016) and were confirmed as independent indicators for a decrease in metastasis-free survival at multivariate analysis. There was no adverse prognostic influence of vascular resection, and there was no increased frequency of disseminated tumor cells in patients undergoing vascular resection.

CONCLUSION

These results support the hypothesis that the presence of vascular tumor involvement of peripancreatic vessels seems to be an indicator of unfavorable tumor topography, instead of being a sign of adverse tumor biology. Thus, vascular resection in pancreatic cancer appears to be warranted to achieve tumor-free margins.

Can the new RCP R0/R1 classification predict the clinical outcome in ductal adenocarcinoma of the pancreatic head?

PURPOSE

According to the International Union Against Cancer (UICC), R1 is defined as the microscopic presence of tumor cells at the surface of the resection margin (RM). In contrast, the Royal College of Pathologists (RCP) suggested to declare R1 already when tumor cells are found within 1 mm of the RM. The aim of this study was to determine the significance of the RM concerning the prognosis of pancreatic ductal adenocarcinoma (PDAC).

METHODS

From 2007 to 2009, 62 patients underwent a curative operation for PDAC of the pancreatic head. The relevance of R status on cumulative overall survival (OS) was assessed on univariate and multivariate analysis for both the classic R classification (UICC) and the suggestion of the RCP.

RESULTS

Following the UICC criteria, a positive RM was detected in 8 %. Along with grading and lymph node ratio, R status revealed a significant impact on OS on univariate and multivariate analysis. Applying the suggestion of the RCP, R1 rate rose to 26 % resulting in no significant impact on OS in univariate analysis.

CONCLUSIONS

Our study has shown that the RCP suggestion for R status has no impact on the prognosis of PDAC. In contrast, our data confirmed the UICC R classification of RM as well as N category, grading, and lymph node ratio as significant prognostic factors.

Significance of lymph node micrometastasis in pancreatic cancer patients

BACKGROUND /AIMS: The present study deals with the significance of lymph node micrometastasis in the survival rate for pancreatic cancer patients.

METHODS

Between January 2006 and December 2010 at the First Department of Surgery in Košice, a prospective trial was done in which we investigated the survival rate after radical pancreatic resection. All negative lymph nodes removed during standard radical lymphadenectomy were subjected to immunohistochemical staining to detect occult micrometastasis. A comparison of the median survival rate in groups of patients with immunohistochemistry-positive and -negative lymph nodes was performed.

RESULTS

Radical pancreatic resection with standard radical lymphadenectomy was performed on 64 pancreatic cancer patients. The median survival time was 15 months. Out of the 319 histopathologically negative lymph nodes (34 patients), 134 lymph nodes were classified as immunohistochemistry positive (21 patients). The median survival rate in the group of patients with immunohistochemistry-negative lymph nodes was 23 months, but in the group of patients with immunohistochemistry-positive lymph nodes it was 14 months. There was a statistically significant difference between these 2 groups of patients (p ≤ 0.01).

CONCLUSION

The immunohistochemical examination of histopathologically negative lymph nodes can lead to positive lymph node detection. The presence of lymph node micrometastasis could predict the survival rate.

Real-time detection of hepatic micrometastases from pancreatic cancer by intraoperative fluorescence imaging: preliminary results of a prospective study

BACKGROUND

Recently, a highly sensitive fluorescent imaging technique was developed for the real-time identification of hepatic tumors. The authors applied this procedure for the intraoperative detection of radiographically occult hepatic micrometastases from pancreatic cancer.

METHODS

Forty-nine consecutive patients with pancreatic cancer who underwent surgical intervention were examined. Preoperative clinical images had not revealed any hepatic metastases. On the day before surgery, indocyanine green was injected intravenously. During the operation, the liver was observed with a near-infrared camera system, and abnormal fluorescent foci were examined by frozen-section histology. The patients with hepatic micrometastases were judged to have unresectable disease and underwent only palliative surgery followed by systemic chemotherapy using gemcitabine.

RESULTS

Abnormal hepatic fluorescence at least 1.5 mm in greatest dimension without any apparent tumor was observed in 13 patients. Among them, histologic examination confirmed micrometastases in 8 of 49 patients (16%). All patients with hepatic micrometastases had clinical T3 or T4 disease and high serum CA19-9 levels (P = .042). On follow-up computed tomography images that were obtained within 6 months after surgery, the patients with hepatic micrometastases manifested hepatic overt metastases (7 of 8 patients; 88%) more frequently than the patients without hepatic micrometastases (4 of 41 patients; 10%; P < .001). Regardless of histologic confirmation, the positive predictive value of abnormal fluorescence for the manifestation of hepatic relapse within 6 months was 77% (10 of 13 patients), and the negative predictive value was 97% (35 of 36 patients).

CONCLUSIONS

Indocyanine green-fluorescent imaging can detect hepatic micrometastases of pancreatic cancer during surgery. The hepatic micrometastases seem to have an adverse clinical impact identical to that of evident distant metastases.

Clinical implications of immunohistochemically demonstrated lymph node micrometastasis in resectable pancreatic cancer

The purpose of this study was to determine the clinical significance of nodal micrometastasis detected by immunohistochemistry in patients that had undergone curative surgery for pancreatic cancer. Between 2005 and 2006, a total of 208 lymph nodes from 48 consecutive patients with pancreatic cancer that had undergone curative resection were immunostained with monoclonal antibody against pan-ck and CK-19. Micrometastasis was defined as metastasis missed by a routine H&E examination but detected during an immunohistochemical evaluation. Relations between immunohistochemical results and clinical and pathologic features and patient survival were examined. Nodal micrometastases were detected in 5 (29.4%) patients of 17 pN0 patients. Nodal micrometastasis was found to be related to tumor relapse (P = 0.043). Twelve patients without overt nodal metastasis and micrometastasis had better prognosis than 5 patients with only nodal micrometastasis (median survival; 35.9 vs 8.6 months, P < 0.001). The Cox proportional hazard model identified nodal micrometastasis as significant prognostic factors. Although the number of patients with micrometastasis was so small and further study would be needed, our study suggests that the lymph node micrometastasis could be the predictor of worse survival and might indicate aggressive tumor biology among patients undergoing curative resection for pancreas cancer.

Surgical implication of micrometastasis for pancreatic cancer

OBJECTIVES

The clinical significance of micrometastasis to regional lymph nodes for pancreas cancer is controversial in patients who underwent curative resection.

METHODS

Nine of 42 patients who underwent macroscopically curative resection of pancreatic head cancer were found to have pN(-) by routine examination. Complete serial section examination of the resected specimens was done to detect micrometastasis in these 9 patients.

RESULTS

A total of 16,505 sections were examined by immunohistochemistry or hematoxylin and eosin staining. Micrometastases were identified in 7 (78%) of 9 patients and 17 (3.6%) of 474 lymph nodes. All micrometastases were found in the pancreas head area. However, the frequency of micrometastases around the superior mesenteric artery was 44%. There were no micrometastases to the para-aortic nodes. There was a tendency that the patients with micrometastases showed better survival than those with overt nodal involvement (P = 0.053). Micrometastasis did not provide the poor prognostic factor in patients who underwent optimal regional lymphadenectomy.

CONCLUSIONS

Even in overtly pN(-) pancreatic cancer, micrometastases occur high frequently (78%) and widely, including the nodes around the superior mesenteric artery. These results provide important pathological information when we consider the preoperative, perioperative, and postoperative strategies, even when patients seem to have no nodal involvement by preoperative examinations.

Lymph node size and metastatic infiltration in adenocarcinoma of the pancreatic head

BACKGROUND

Preoperative lymph node staging of pancreatic cancer by CT relies on the premise that malignant lymph nodes are larger than benign nodes. In imaging procedures lymph nodes >1 cm in size are regarded as metastatic nodes. The extend of lymphadenectomy and potential application of neoadjuvant therapy regimens could be dependent on this evaluation.

PATIENTS AND METHODS

In a morphometric study regional lymph nodes from 52 patients with pancreatic cancer were analyzed. The lymph nodes were counted, the largest diameter of each node was measured, and each node was analyzed for metastatic involvement by histopathological examination. The frequency of metastatic involvement was calculated and correlated with lymph node size.

RESULTS

A total of 636 lymph nodes were present in the 52 specimens examined for this study (12.2 lymph nodes per patient). Eleven patients had a pN0 status, whereas 41 patients had lymph nodes that were positive for cancer. Five-hundred-twenty (82%) lymph nodes were tumor-free, while 116 (18%) showed metastatic involvement on histopathologic examination. The mean (±SD) diameter of the nonmetastatic nodes was 4.3 mm, whereas infiltrated nodes had a diameter of 5.7 mm (p = 0.001). Seventy-eight (67%) of the infiltrated lymph nodes and 433 (83%) of the nonmetastatic nodes were ≤5 mm in diameter. Of 11 pN0 patients, 5 (45%) patients had at least one lymph node ≥10 mm, in contrast only 12 (29%) out of 41 pN1 patients had one lymph node ≥10 mm.

CONCLUSION

Lymph node size is not a reliable parameter for the evaluation of metastatic involvement in patients with pancreatic cancer.

Significance of M2-polarized tumor-associated macrophage in pancreatic cancer

BACKGROUND

The roles of infiltrating macrophages within the tumor microenvironment are complex because of their functional variety. The aim of this study is to examine the role and prognostic significance of tumor-associated macrophages (TAMs) that have an M2 polarized function in pancreatic cancer.

MATERIALS AND METHODS

Formalin-fixed, paraffin-embedded blocks were obtained from 76 patients with pancreatic head cancer. All patients underwent macroscopic curative resection. We assessed the number of infiltrating macrophages within the tumor invasive front by not only CD68 but also by CD163 and CD204, which are specific receptors on M2-polarized macrophages. Furthermore, to evaluate lymphangiogenesis, we measured the density of lymphatic vessels in the tumor invasive front by using D2-40.

RESULTS

High incidence of lymph node metastasis was shown in cases with a high number of CD163- or CD204-positive macrophages. Significantly increased lymphatic vessel density (LVD) was shown in cases with lymph node metastasis compared with cases without lymph node metastasis (P=0.0094). Significantly increased LVD (P=0.0175) and a poor prognosis (P=0.0171) were shown in cases with a high number of macrophages that express CD163 or CD204, however, there was no significant difference according to the number of CD68-positive macrophages.

CONCLUSIONS

M2-polarized TAMs in the invasive front of pancreatic cancer are associated with a poor prognosis due to accelerated lymphatic metastasis, and inhibition of the functional interaction between M2-polarized TAMs and tumor cells may improve the prognosis.

Surgical management of carcinoma of the head of pancreas: extended lymphadenectomy or modified en bloc resection?

Pancreatoduodenectomy for the treatment of periampullary cancer was described over 70 years ago. The technique has evolved in an attempt to improve the dismal prognosis for patients with pancreatic cancers. Radical regional resection has been proposed to decrease the incidence of local recurrence as well as to improve survival. These extended resections have failed to show a significant survival benefit in prospective randomized controlled studies. Furthermore, extended pancreatic resections may be associated with increased morbidity. The concept of modified en bloc resection has been advocated and is soundly based on anatomical and pathological principals. This procedure is a modification of the radical regional resection previously described. It involves resection of the peripancreatic retroperitoneal tissue and lymph nodes en bloc with the head of pancreas, in order to achieve an R0 resection but without the morbidity associated with an extended lymphadenectomy. Conceptually, this procedure may be the most appropriate technique for the management of pancreatic head cancers although the ultimate effect on long-term survival can only be judged after further clinical studies.

Most pancreatic cancer resections are R1 resections

BACKGROUND

Curative resection has been shown to be one of the key factors influencing survival of pancreatic ductal adenocarcinoma (PDAC) patients. Although general guidelines for the processing of pancreatic specimens have been established, there is currently no widely accepted standardized protocol for pathological examination, especially with respect to resection margins.

METHODS

Here we present a single-center experience with 111 consecutive macroscopic complete pancreatic head resections for PDAC carried out between 2005 and 2006 by using standardized pathological processing and reporting. The pancreatic transection margin, as well as the bile duct and stomach/duodenum margins and the circumferential soft tissue margins (medial, anterior surface, superior, and posterior), were inked and analyzed. R1 was defined as a distance of the tumor from the resection margin of < or = 1 mm.

RESULTS

One hundred eighty-eight consecutive macroscopic complete pancreatic head resections carried out for PDAC without a standardized protocol between 2002 and 2004 were used as a control group. The R1 rate for resections carried out with the standardized protocol was 76%. The medial (68%) and the posterior (47%) margins were most commonly involved, and in 32% of the cases, more than one margin was affected. The R1 resection rate in the period without standardized pathological reporting was 14%.

CONCLUSIONS

This study highlights the importance of pathological reporting and suggests that tumor growth patterns and thorough examination but not surgical technique determine R1 resection rates in PDAC.

CD133 expression is correlated with lymph node metastasis and vascular endothelial growth factor-C expression in pancreatic cancer

Although CD133 has been shown to be a marker for cancer stem cells in various tumours, its expression in pancreatic cancer has not yet been clinically reported. In this study, we investigated the relationship between CD133 expression and clinicopathological factors in pancreatic cancer. Pancreatic head carcinoma specimens from 80 patients who underwent surgical resection were immunohistochemically assessed for CD133, vascular endothelial growth factor (VEGF)-C, CXCR4, CD34, Ki-67, and cytokeratin (CK) expressions. Sixty percentage (48/80) of specimens were CD133-positive, with less than 15% cells per specimen expressing the marker. CD133-positive cells were found at the peripheral site of adenocarcinoma glandular structures and were negative for CK. There was a significant correlation between CD133 expression and clinicopathological factors, including histological type, lymphatic invasion, and lymph node metastasis (P=0.0215, 0.0023, and 0.0024, respectively). Vascular endothelial growth factor-C expression was also significantly correlated with CD133 expression (P=0.0002). Consequently, the 5-year survival rate of CD133-positive patients was significantly lower than that of CD133-negative patients (P=0.0002) and multivariate analysis revealed that CD133 expression was an independent prognostic factor (P=0.0103). These results suggest that CD133 expression in pancreatic cancer was significantly associated with lymphatic metastasis, VEGF-C expression, and prognosis.

PAM4-reactive MUC1 is a biomarker for early pancreatic adenocarcinoma

PURPOSE

The anti-MUC1 monoclonal antibody (MAb), PAM4, has a high specificity for pancreatic adenocarcinoma compared with other cancers, normal tissues, or pancreatitis. In order to assess its role in early pancreatic cancer development, we examined the expression of the PAM4-reactive MUC1 in the noninvasive precursor lesions, pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasia (IPMN).

EXPERIMENTAL DESIGN

Tissue microarrays prepared from formalin-fixed, paraffin-embedded specimens were assessed by immunohistology for expression of the PAM4-reactive, non-variable number of tandem repeats (VNTR), MUC1 epitope, and the VNTR epitope bound by the MA5 MAb.

RESULTS

The PAM4-reactive MUC1 epitope was not detected in normal pancreas but was expressed in 87% (48 of 55) of invasive pancreatic adenocarcinomas, including early stage 1 disease: PAM4 labeled 94% (44 of 47) of the earliest PanIN lesions, PanIN-1A and 1B, along with 91% (10 of 11) of PanIN-2, 40% (2 of 5) of PanIN-3, and 86% (31 of 36) of intraductal papillary mucinous neoplasia lesions. A mostly diffuse pattern of labeling was observed. A second, unrelated, anti-MUC1 MAb, MA5, showed considerably less sensitivity with early PanIN-1 lesions; only 61% (25 of 41) were positive and the labeling did not differentiate normal pancreas from PanINs.

CONCLUSIONS

The results suggest that expression of the PAM4-reactive antigen may represent an early event in the development of invasive pancreatic adenocarcinoma, and is unrelated to the VNTR peptide core epitopes of MUC1. Detection of this biomarker using immunohistology, in vitro immunoassays, and in vivo antibody-based imaging may provide new opportunities for the early detection and improved diagnosis of pancreatic cancer.

Pancreatic cancer: a generalized disease--prognostic impact of cancer cell dissemination

BACKGROUND

Pancreatic ductal adenocarcinoma is the fifth leading cause of death among all malignancies, leading to approximately 40,000 deaths each year in Europe. The annual incidence rate for all types of pancreatic cancer is approximately nine new cases per 100,000 people, ranking it as the 11th among all cancers. Stage, grade and resection margin status are currently accepted as the most accurate pathologic variables predicting survival. All classification systems fail prognostically to distinguish between different stages. Even in patients with seemingly early tumours (T1, N0), the likelihood of relapse is high. This reflects the shortcomings of the pathologic staging to sufficiently discriminate patients with a high risk to develop tumour recurrence from those that carry a lower risk.

RESULTS

On the other hand, none of the currently used systems includes or takes into consideration the role of disseminated tumour cells neither in the lymph nodes nor in the bone marrow. Occult residual tumour disease is suggested when either bone marrow or lymph nodes, from which tumour relapse may originate, are affected by micrometastatic lesions undetectable by conventional histopathology. For detection, antibodies against tumour-associated targets can be used to detect individual epithelial tumour cells both in lymph nodes and in bone marrow. The clinical significance of these immunohistochemical analyses is still controversial. Various monoclonal antibodies are still in use for micrometastatic detection, thus contributing to the incongruity of data and validity of results. These assays have been rarely used in patients with pancreatic carcinoma.

CONCLUSION

The presence or absence of lymph-node metastases can predict the likelihood of survival for most, if not all, patients with pancreatic ductal adenocancer and the likelihood that metastases will develop at distant sites.