Computertomographie bei Pankreastumoren

Diagnostic, Structured Classification and Therapeutic Approach in Cystic Pancreatic Lesions: Systematic Findings with Regard to the European Guidelines

Due to the increasing use of cross-sectional imaging techniques and new technical possibilities, the number of incidentally detected cystic lesions of the pancreas is rapidly increasing in everyday radiological routines. Precise and rapid classification, including targeted therapeutic considerations, is of essential importance. The new European guideline should also support this. This review article provides information on the spectrum of cystic pancreatic lesions, their appearance, and a comparison of morphologic and histologic characteristics. This is done in the context of current literature and clinical value. The recommendations of the European guidelines include statements on conservative management as well as relative and absolute indications for surgery in cystic lesions of the pancreas. The guidelines suggest surgical resection for mucinous cystic neoplasm (MCN) ≥ 40 mm; furthermore, for symptomatic MCN or imaging signs of malignancy, this is recommended independent of its size (grade IB recommendation). For main duct IPMNs (intraductal papillary mucinous neoplasms), surgical therapy is always recommended; for branch duct IPMNs, a number of different risk criteria are applicable to evaluate absolute or relative indications for surgery. Based on imaging characteristics of the most common cystic pancreatic lesions, a precise diagnostic classification of the tumor, as well as guidance for further treatment, is possible through radiology.

Lymph node metastases and recurrence in pancreatic neuroendocrine neoplasms

BACKGROUND

The impact of lymph node metastasis on survival in pancreatic neuroendocrine neoplasms as well as their best surgical treatment is controversial. We aimed to determine the frequency and prognostic impact of lymph node involvement in pancreatic neuroendocrine neoplasms.

METHODS

Patients undergoing pancreatic resections for pancreatic neuroendocrine neoplasms between 2001 and 2019 were retrospectively analyzed based on a prospective database. Clinicopathological parameters and perioperative outcome were assessed. Overall and disease-free survival was analyzed. Subgroup analysis was performed for sporadic, nonfunctional pancreatic neuroendocrine neoplasms without distant metastases and ≥4 analyzed lymph nodes.

RESULTS

Of 605 surgically resected pancreatic neuroendocrine neoplasms, 55% were G1, 36% were G2, and 9% were G3 differentiated. At the time of resection, 34% of patients had lymph node metastasis, and 16% had distant metastases. For subgroup analysis, 314 patients were analyzed. Lymph node metastases occurred in 36% of patients and were most frequent in G3 patients (67%). An increase in tumor size and advancement was associated with higher rates of lymph node metastasis, and disease-free survival was significantly impaired. Significant differences in disease-free survival were observed between 1 and 3 (5-year disease-free survival 52%) and ≥4 positive lymph nodes (5-year disease-free survival 28%), as well as when G3 tumors were excluded. In multivariable analysis, grading, tumor stage, and especially lymph node metastases as well as the proposed pN1 and pN2 categories were confirmed as independent predictors of recurrence.

CONCLUSION

The presence and extent of lymph node involvement has considerable prognostic impact in pancreatic neuroendocrine neoplasms. This study, for the first time, validated the proposed pN2 stage for well-differentiated pancreatic neuroendocrine neoplasms.

Enucleation Is a Feasible Procedure for Well-Differentiated pNEN-A Matched Pair Analysis

The extent of surgical resection in the treatment of pancreatic neuroendocrine neoplasms (pNEN) is still controversial. This study aimed to evaluate the outcomes of enucleation for well-differentiated non-functional (nf) pNEN. Patients undergoing enucleation (2001−2020) were analyzed. Clinicopathological parameters, perioperative outcomes and survival were assessed. The analysis was performed as a nested case-control study and matched-pair analysis with formal resection. Sixty-one patients undergoing enucleation were identified. Compared to patients undergoing formal resection, enucleation was associated with a significantly shorter median length of operative time (128 (IQR 95−170) versus 263 (172−337) minutes, p < 0.0001) and a significantly lower rate of postoperative diabetes (2% versus 21%, p = 0.0020). There was no significant difference in postoperative pancreatic fistula rate (18% versus 16% type B/C, p = 1.0), Clavien−Dindo ≥ III complications (20% versus 26%, p = 0.5189), readmission rate (12% versus 15%, p = 0.6022) or length of hospital stay (8 (7−11) versus 10 (8−17) days, p = 0.0652). There was no 30-day mortality after enucleation compared to 1.6% (n = 1) after formal resection. 10-year overall survival (OS) and disease-free survival (DFS) was similar between the two groups (OS: 89% versus 77%, p = 0.2756; DFS: 98% versus 91%, p = 0.0873). Enucleation presents a safe surgical approach for well-differentiated nf-pNEN with good long-term outcomes for selected patients.

Imaging of inflammatory disease of the pancreas

Increasingly acute and chronic pancreatitis (AP and CP) are considered a continuum of a single entity. Nonetheless, if, after flare-up, the pancreas shows no residual inflammation, it is classified as AP. CP is characterised by a long cycle of worsening and waning glandular inflammation without the pancreas ever returning to its baseline structure or function. According to the International Consensus Guidelines on Early Chronic Pancreatitis, pancreatic inflammation must last at least 6 months before it can be labelled CP. The distinction is important because, unlike AP, CP can destroy endocrine and exocrine pancreatic function, emphasising the importance of early diagnosis. As typical AP can be diagnosed by clinical symptoms plus laboratory tests, imaging is usually reserved for those with recurrent, complicated or CP. Imaging typically starts with ultrasound and more frequently with contrast-enhanced computed tomography (CECT). MRI and/or MR cholangiopancreatography can be used as a problem-solving tool to confirm indirect signs of pancreatic mass, differentiate between solid and cystic lesions, and to exclude pancreatic duct anomalies, as may occur with recurrent AP, or to visualise early signs of CP. MR cholangiopancreatography has replaced diagnostic endoscopic retrograde cholangiopancreatography (ERCP). However, ERCP, and/or endoscopic ultrasound (EUS) remain necessary for transpapillary biliary or pancreatic duct stenting and transgastric cystic fluid drainage or pancreatic tissue sampling, respectively. Finally, positron emission tomography-MRI or positron emission tomography-CT are usually reserved for complicated cases and/or to search for extra pancreatic systemic manifestations. In this article, we discuss a broad spectrum of inflammatory pancreatic disorders and the utility of various modalities in diagnosing acute and chronic pancreatitis.

Role of CT texture features for predicting outcome of pancreatic cancer patients with liver metastases

Objective: The purpose of this study was to evaluate the prognostic value of computed tomography (CT) texture features of pancreatic cancer with liver metastases. Methods: We included 39 patients with metastatic pancreatic cancer (MPC) with liver metastases and performed texture analysis on primary tumors and metastases. The correlations between texture parameters were assessed using Pearson's correlation. Univariate Cox proportional hazards model was used to assess the correlations between clinicopathological characteristics, texture features and overall survival (OS). The univariate Cox regression model revealed four texture features potentially correlated with OS (P<0.1). A radiomics score (RS) was determined using a sequential combination of four texture features with potential prognostic value that were weighted according to their β-coefficients. Furthermore, all variables with P<0.1 were included in the multivariate analysis. A nomogram,which was developed to predict OS according to independent prognostic factors, was internally validated using the C-index and calibration plots. Kaplan-Meier analysis and the log-rank test were performed to stratify OS according to the RS and nomogram total points (NTP). Results: Few significant correlations were found between texture features of primary tumors and those of liver metastases. However, texture features within primary tumors or liver metastases were significantly associated. Multivariate analysis showed that Eastern Cooperative Oncology Group performance status (ECOG PS), chemotherapy, Carbohydrate antigen 19-9 (CA19-9), and the RS were independent prognostic factors (P<0.05). The nomogram incorporating these factors showed good discriminative ability (C-index = 0.754). RS and NTP stratified patients into two potential risk groups (P<0.01). Conclusion: The RS derived from significant texture features of primary tumors and metastases shows promise as a prognostic biomarker of OS of patients with MPC. A nomogram based on the RS and other independent prognostic clinicopathological factors accurately predicts OS.

Borderline resectable pancreatic cancer

Surgery followed by adjuvant chemotherapy remains the only treatment option for pancreatic ductal adenocarcinoma (PDAC) with the chance of long-term survival. If a radical tumor resection is possible, 5-year survival rates of 20-25% can be achieved. Pancreatic surgery has significantly changed during the past years and resection approaches have been extended beyond standard procedures, including vascular and multivisceral resections. Consequently, borderline resectable pancreatic ductal adenocarcinoma (BR-PDAC), which has recently been defined by the International Study Group for Pancreatic Surgery (ISGPS), has become a controversial issue with regard to its management in terms of upfront resection vs. neoadjuvant treatment and sequential resection. Preoperative diagnostic accuracy to define resectability of PDAC is a keypoint in this context as well as the surgical and interdisciplinary expertise to perform advanced pancreatic surgery and manage complications. The present mini-review summarizes the current state of definition, management and outcome of BR-PDAC. Furthermore, the topic of ongoing and future studies on neoadjuvant treatment which is closely related to borderline resectability in PDAC is discussed.

Outcome of surgery for pancreatic neuroendocrine neoplasms

BACKGROUND

The incidence of pancreatic neuroendocrine neoplasms (pNEN) is increasing. This study aimed to evaluate predictors of overall survival and the indication for surgery.

METHODS

Data collected between October 2001 and December 2012 were analysed. Histological grading and staging was based on the classifications of the World Health Organization, the International Union Against Cancer and the European Neuroendocrine Tumour Society.

RESULTS

Some 310 patients (150 female, 48·4 per cent) underwent surgical resection. The final survival analysis included 291 patients. Five-year overall survival differed according to tumour grade (G): 91·0 per cent among 156 patients with pancreatic neuroendocrine tumours (pNET) G1, 70·8 per cent in 111 patients with pNET G2, and 20 per cent in 24 patients with pancreatic neuroendocrine carcinomas (pNEC) G3 (P < 0·001). Tumours graded G3 (hazard ratio (HR) 6·96, 95 per cent confidence interval 3·67 to 13·21), the presence of distant metastasis (HR 2·41, 1·32 to 4·42) and lymph node metastasis (HR 2·10, 1·07 to 4·16) were independent predictors of worse survival (P < 0·001, P = 0·004 and P = 0·032 respectively). Eight of 61 asymptomatic patients with pNEN smaller than 2 cm had tumours graded G2 or G3, and six of 51 patients had lymph node metastasis. Among patients with pNEC G3, the presence of distant metastasis had a significant impact on the 5-year overall survival rate: 0 per cent versus 43 per cent in those without distant metastasis (P = 0·036).

CONCLUSION

Neuroendocrine tumours graded G3, lymph node and distant metastasis are independent predictors of worse overall survival in patients with pNEN.

A tumour score with multidetector spiral CT for venous infiltration in pancreatic cancer: influence on borderline resectable

PURPOSE

A tumour score for venous invasion in patients with pancreatic adenocarcinoma was evaluated by means of computed tomography (CT), in order to improve the assessment of medical treatment and clinical outcome with special attention to borderline resectable disease.

MATERIALS AND METHODS

Fifty-six consecutive patients who underwent curative surgical resection for pancreatic cancer were analysed. On the basis of CT criteria, tumour involvement of the portal vein (PV) and superior mesenteric vein (SMV) was graded according to an adapted 4-point scale: score 1, definite absence of invasion; score 2, probable absence of invasion; score 3, probable presence of invasion; score 4, definite presence of invasion. Correlations between the venous infiltration scores and the patients' clinical features were also evaluated.

RESULTS

After radiological evaluation of PV and SMV grades of infiltration, 21/56 (37 %) and 37/56 (66 %) patients, respectively, were found to have borderline resectable disease. The 4-point scale achieved a sensitivity of 80 %, a specificity of 96 % and an accuracy of 93 % in the evaluation of the PV, and a sensitivity of 100 %, a specificity of 94 % and an accuracy of 95 % in the evaluation of the SMV. Analysis of the distribution of clinical characteristics by PV and SMV infiltration showed that both scores correlated with the presence of distal metastasis (p = 0.016 and p = 0.028, respectively), and resection margins status (p = 0.015 and p = 0.006, respectively).

CONCLUSIONS

This adapted tumour score is reliable for assessing venous invasion and might improve preoperative staging in patients with borderline resectable pancreatic cancer.

Development and validation of automatic tools for interactive recurrence analysis in radiation therapy: optimization of treatment algorithms for locally advanced pancreatic cancer

BACKGROUND

In radiation oncology recurrence analysis is an important part in the evaluation process and clinical quality assurance of treatment concepts. With the example of 9 patients with locally advanced pancreatic cancer we developed and validated interactive analysis tools to support the evaluation workflow.

METHODS

After an automatic registration of the radiation planning CTs with the follow-up images, the recurrence volumes are segmented manually. Based on these volumes the DVH (dose volume histogram) statistic is calculated, followed by the determination of the dose applied to the region of recurrence and the distance between the boost and recurrence volume. We calculated the percentage of the recurrence volume within the 80%-isodose volume and compared it to the location of the recurrence within the boost volume, boost + 1 cm, boost + 1.5 cm and boost + 2 cm volumes.

RESULTS

Recurrence analysis of 9 patients demonstrated that all recurrences except one occurred within the defined GTV/boost volume; one recurrence developed beyond the field border/outfield. With the defined distance volumes in relation to the recurrences, we could show that 7 recurrent lesions were within the 2 cm radius of the primary tumor. Two large recurrences extended beyond the 2 cm, however, this might be due to very rapid growth and/or late detection of the tumor progression.

CONCLUSION

The main goal of using automatic analysis tools is to reduce time and effort conducting clinical analyses. We showed a first approach and use of a semi-automated workflow for recurrence analysis, which will be continuously optimized. In conclusion, despite the limitations of the automatic calculations we contributed to in-house optimization of subsequent study concepts based on an improved and validated target volume definition.

CT and MR imaging patterns for pancreatic carcinoma invading the extrapancreatic neural plexus (Part II): Imaging of pancreatic carcinoma nerve invasion

Computed tomography (CT) and magnetic resonance imaging (MRI) are excellent modalities which have the ability to detect, depict and stage the nerve invasion associated with pancreatic carcinoma. The aim of this article is to review the CT and MR patterns of pancreatic carcinoma invading the extrapancreatic neural plexus and thus provide useful information which could help the choice of treatment methods. Pancreatic carcinoma is a common malignant neoplasm with a high mortality rate. There are many factors influencing the prognosis and treatment options for those patients suffering from pancreatic carcinoma, such as lymphatic metastasis, adjacent organs or tissue invasion, etc. Among these factors, extrapancreatic neural plexus invasion is recognized as an important factor when considering the management of the patients.

[Neuroendocrine tumors of the duodenum and pancreas. Surgical strategy]

The incidence of neuroendocrine tumors (NET) has increased worldwide by 3-5 times over the last decades. This is mainly based on the broad use of imaging modalities such as computed tomography (CT) and endoscopic approaches. As a consequence many duodenal and pancreatic tumors are detected in an early stage resulting in an improved prognosis of these patients. Besides the measurement of serum chromogranin A and 5-hydroxy indolic acid measured in 24 h urine collection, CT, endosonographic ultrasound (EUS) and endoscopy are important diagnostic tools. About 20% of all patients with pancreatic and duodenal NETs are diagnosed because of specific symptoms. More than 95% of diagnosed NETs are sporadic tumors. Whenever possible these patients should be treated by resection. Benign neuroendocrine duodenal tumors up to 1 cm in size can be removed endoscopically. The endoscopic resection of larger tumors should be performed surgically. The therapy of hereditary NETs of the duodenum and the pancreas should be decided after interdisciplinary discussion. However, even these patients seem to benefit from resection. In case of metastatic disease debulking surgery should be considered if more than 90% of the tumor mass can be resected. In patients with extensive liver metastases but resectable primary NET, liver transplantation is a reasonable option. There is no consensus about adjuvant or neoadjuvant treatment of duodenal or pancreatic NETs. The therapy with everolimus or sunitinib in advanced tumor stages has shown promising results. The administration of somatostatin analogues or antacids is appropriate for symptom reduction.

The predictive value of mean platelet volume in differential diagnosis of non-functional pancreatic neuroendocrine tumors from pancreatic adenocarcinomas

OBJECTIVE

The aim of the present study is to evaluate in a retrospective manner the diagnostic value of mean platelet volume (MPV) in pancreatic adenocarcinomas and pancreatic neuroendocrine tumors (PNETs).

PATIENTS AND METHODS

A total of 92 patients, who were admitted for pancreatic adenocarcinoma (n=76) and PNET (n=16) between March 2007 and December 2009, were analyzed retrospectively for demographics and clinical information.

RESULTS

Thirty-nine patients (51.3%) had a resectable, whereas 37 patients (48.7%) had an unresectable pancreatic adenocarcinoma. Nine patients (56.3%) had a non-functional PNET, 6 patients (37.5%) had an insulinoma, and the remaining one patient had a gastrinoma. The mean age was 59.3±10.5 for pancreatic adenocarcinomas and 45.1±10.6 for PNETs. The mean age at diagnosis was significantly higher in patients with pancreatic adenocarcinomas than the patients with PNET (p<0.001). Preoperative mean hemoglobin levels were significantly lower in patients with pancreatic adenocarcinoma than those with PNET (12.4±1.8g/dl vs 13.7±2.2g/dl), (p<0.013). The preoperative median MPV levels were significantly lower in patients with PNET 7.8fL (7.2-9.4) than in patients with pancreatic adenocarcinomas 8.6fL (6.6-13.5), (p<0.014). In subgroup analysis, a significant difference in MPV levels was mainly caused by the difference between pancreatic adenocarcinomas and non-functional PNETs (p=0.017). The cut-off value of MPV level for detection of PNETs was calculated as≤7.8fL using ROC analysis [Sensitivity: 66.7%, specificity: 75.9%, AUC: 0.734 (0.587-0.880) p=0.022]. In logistic regression analysis, independent predictive factors for determining PNETs in the differential diagnosis of pancreatic adenocarcinomas were calculated as age (OR=0.068, 95% CI: 0.012-0.398), Ca 19-9 (OR=0.039, 95% CI: 0.006-0.263), MPV (OR=0.595, 95% CI: 0.243-1.458), and hemoglobin (OR=1.317, 95% CI: 0.831-2.086).

CONCLUSION

Age, Ca 19-9, MPV, and hemoglobin levels have diagnostic value for distinguishing PNETs from pancreatic adenocarcinomas.

[Diffusion-weighted imaging of the pancreas]

Diffusion-weighted imaging (DWI) has increasingly gained in importance over the last 10 years especially in cancer imaging for differentiation of malignant and benign lesions. Through development of fast magnetic resonance imaging (MRI) sequences DWI is not only applicable in neuroradiology but also in abdominal imaging. As a diagnostic tool of the pancreas DWI enables a differentiation between normal tissue, cancer and chronic pancreatitis. The ADC values (apparent diffusion coefficient, the so-called effective diffusion coefficient) reported in the literature for healthy pancreatic tissue are in the range from 1.49 to 1.9×10(-3) mm(2)/s, for pancreatic cancer in the range from 1.24 to 1.46×10(-3) mm(2)/s and for autoimmune pancreatitis an average ADC value of 1.012×10(-3) mm(2)/s. There are controversial data in the literature concerning the differentiation between chronic pancreatitis and pancreatic cancer. Using DWI-derived IVIM (intravoxel incoherent motion) the parameter f (perfusion fraction) seems to be advantageous but it is important to use several b values. In the literature the mean f value in chronic pancreatitis is around 16%, in pancreatic cancer 8% and in healthy pancreatic tissue around 25%. So far, DWI has not been helpful for differentiating cystic lesions of the pancreas. There are many references with other tumor entities and in animal models which indicate that there is a possible benefit of DWI in monitoring therapy of pancreatic cancer but so far no original work has been published.

Intravoxel incoherent motion MRI for the differentiation between mass forming chronic pancreatitis and pancreatic carcinoma

PURPOSE

To determine which of the quantitative parameters obtained from intravoxel incoherent motion diffusion weighted imaging (DWI) is the most significant for the differentiation between pancreatic carcinoma and mass-forming chronic pancreatitis.

MATERIALS AND METHODS

Twenty-nine patients with pancreatic masses were included, 9 proved to have a mass-forming pancreatitis and 20 had a pancreatic carcinoma. The patients were studied using intravoxel incoherent motion DWI with 11 b-values and the apparent diffusion coefficient (ADC), the true diffusion constant (D) and the perfusion fraction (f) were calculated. The diagnostic strength of the parameters was evaluated using receiver operating characteristic analysis.

RESULTS

The ADC in chronic pancreatitis was higher than in pancreatic carcinoma with significant differences at b = 50, 75, 100, 150, 200, 300 s/mm (ADC50 = 3.17 ± 0.67 vs. 2.55 ± 1.09, ADC75 = 2.46 ± 0.4 vs. 1.93 ± 0.52, ADC100 = 2.28 ± 0.48 vs. 1.73 ± 0.45, ADC150 = 1.97 ± 0.26 vs. 1.63 ± 0.40, ADC200 = 1.98 ± 0.24 vs. 1.53 ± 0.28, and ADC300 = 1.76 ± 0.19 vs. 1.46 ± 0.31 × 10(-3) mm2/s). No significant differences were found at b = 25, 400, 600, and 800 s/mm (ADC25 = 4.69 ± 0.65 vs. 4.04 ± 1.35, ADC400 = 1.57 ± 0.21 vs. 1.37 ± 0.30, ADC600 = 1.38 ± 0.18 vs. 1.24 ± 0.25, and ADC800 = 1.27 ± 0.10 vs. 1.18 ± 0.19 × 10(-3) mm2/s) nor using ADCtot (1.42 ± 0.23 vs. 1.28 ± 0.12 × 10(-3) mm2/s). The perfusion fraction f was significantly higher in pancreatitis compared with pancreatic carcinoma (16.3% ± 5.30% vs. 8.2% ± 4.00%, P = 0.0001). There was no significant difference between groups for D (1.07 ± 0.224 × 10(-3) mm2/s for chronic pancreatitis and 1.09 ± 0.3 × 10(-3) mm2/s for pancreatic carcinoma, P = 0.66). For f, the highest area under the curve (0.894) and combined sensitivity (80%) and specificity (89.9%) were found.

CONCLUSIONS

There were significant differences in ADC50-300 between chronic pancreatitis and pancreatic carcinoma. Because D is not significantly different between groups, differences in ADC can be attributed mainly to differences in perfusion. The perfusion fraction f proved to be the superior DWI-derived parameter for differentiation of mass-forming pancreatitis and pancreatic carcinoma.

Limitations in improving detection of pancreatic adenocarcinoma

OBJECTIVE

To review the current trends in pancreatic cancer research and propose alternatives for an earlier diagnosis.

METHOD

A search was conducted using the PubMed and Scielo electronic databases to find statistics related to the incidence of pancreatic cancer.

RESULTS

Pancreatic cancer is the fourth most common cause of cancer mortality in the USA; in Colombia the incidence of this neoplasia is 4.5 per 100,000 individuals; and in Peru, amongst digestive diseases, it is the fifth most common cause. In Brazil and Chile this cancer has increased in incidence, while in Mexico, it has decreased in terms of the relative percentage of gastrointestinal cancers from 1976 to 2003. Chronic pancreatitis, cigarette smoking, diabetes, obesity and dietary mutagen exposure are the most consistent risk factors implicated in the development of pancreatic cancer; however, the genetic and molecular changes underlying the epidemiological association between these factors and pancreatic cancer remain largely unknown, and only 5-10% are hereditary in nature.

CONCLUSION

The prognosis for pancreatic cancer has not changed substantially for at least the last 20 years. The most useful tumor marker for pancreatic adenocarcinoma is still the carbohydrate antigen 19-9 (CA19-9). Currently, a multimodal-screening approach of endoscopic ultrasound, computed tomography and endoscopic retrograde cholangiopancreatography are the most effective methods to detect pancreatic cancer in high-risk patients. Future options for early detection of this malignancy are focused on new molecular markers, telomerase enzyme, receptor-targeted imaging using multifunctional nanoparticles, detection of glycan changes and epigenetics.