Treatment Approaches to Locally Advanced Pancreatic Adenocarcinoma

The value of dynamic contrast enhanced ultrasound (DCE-US) in monitoring treatment effect of high-intensity focused ultrasound (HIFU) in locally advanced pancreatic cancer (LAPC)

PURPOSE

To evaluate the feasibility of dynamic contrast enhanced ultrasound (DCE-US) in predicting treatment response of high-intensity focused ultrasound (HIFU) in patients with locally advanced pancreatic cancer (LAPC) lesions.

PATIENTS AND METHODS

In this prospective study, 10 patients with pathologically confirmed LAPC lesions (7 men, 3 women; average age, 61.13±5.80 years) were prospectively enrolled. All patients received HIFU treatment with peak intensity at 12000 W/cm2. Contrast enhanced ultrasound (CEUS) was performed with an ACUSON Oxana 2 ultrasound equipment and a 6 C-1 transducer (1-6 Hz). A dose of 2.4 ml SonoVue was injected for each examination. Time intensity curves (TICs) were generated and quantitative analyses were performed by SonoLiver software. B mode ultrasound (BMUS) features, CEUS enhancement patterns, TICs, CEUS quantitative parameters and serum carcinoma antigen 19-9 (CA19-9) levels were compared before and 4 weeks after HIFU treatment. Statistical analyses were performed with SPSS Version 20.0 and GraphPad Prism 5.

RESULTS

While comparing before and after HIFU, no significant difference was obtained on mean size of lesion, BMUS or CEUS features. After HIFU treatment, TICs showed decreased and delayed enhancement. Among all CEUS quantitative parameters, significant decrease could be found in maximum intensity (MI) (60.66±23.95% vs 41.31±26.74%) and mean transit time (mTT) (76.66±47.61 s vs 38.42±28.35 s). CA19-9 level decreased significantly after HIFU (2747.92±4237.41 U/ml vs 715.08±1773.90 U/ml) (P = 0.05).

CONCLUSION

DCE-US combining with quantitative analysis might be a useful imaging method for early treatment response evaluation of HIFU in LAPC lesions.

Detection of pancreatic ductal adenocarcinoma and liver metastases: comparison of Gd-EOB-DTPA-enhanced MR imaging vs. extracellular contrast materials

PURPOSE

To compare the detectability of pancreatic ductal adenocarcinoma (PDAC) and liver metastases between Gd-EOB-DTPA- and extracellular contrast materials (ECCMs) contrast-enhanced MR imaging contrast.

METHODS

Two hundred seventy-two patients with suspected pancreatic disease underwent Gd-EOB-DTPA-enhanced MR imaging (EOB group, n = 79) or ECCMs-enhanced MR imaging (ECCM group, n = 193). The ECCM group were administered the following contrast agents: Gd-DTPA (n = 158), Gd-BT-DO3A (n = 28), Gd-DOTA (n = 5), and Gd-DTPA-BMA (n = 2). Signal intensities of pancreatic parenchyma, paraspinal muscle, PDAC (if present), and background noise were measured. The signal intensity ratio (SIR) of the pancreas and tumor-to-pancreas contrast-to-noise ratio (CNR) were also calculated. If present, the conspicuity of PDAC was evaluated with the arterial dominant phase images. Liver metastases, if present, were also evaluated for all sequences. Qualitative and quantitative imaging parameters were compared between EOB and ECCM groups.

RESULTS

SIR of the pancreas (P < 0.001) and CNR (P = 0.0037) were significantly lower in EOB group when compared with the ECCM group. However, the sensitivity (97.1% vs. 93.5%, P = 0.42) and specificity (100.0% vs. 99.2%, P = 1.00) for detecting PDAC were not significant between EOB and ECCM groups. The EOB group showed a significantly greater sensitivity for detecting liver metastases compared with the ECCM group (95.0% vs 84.5%, P = 0.04) when evaluating on a lesion-by-lesion basis.

CONCLUSION

Gd-EOB-DTPA-enhanced MR imaging performed similarly to ECCMs-enhanced MR imaging in detecting PDAC but had better sensitivity in detecting liver metastases.

Clinical application of dynamic contrast enhanced ultrasound in monitoring the treatment response of chemoradiotherapy of pancreatic ductal adenocarcinoma

OBJECTIVES

To investigate the value of dynamic contrast enhanced ultrasound (D-CEUS) in monitoring the chemoradiotherapy (CRT) therapeutic response of local advanced pancreatic ductal adenocarcinoma (LAPC).

PATIENTS AND METHODS

From October 2017 to December 2018, 11 patients diagnosed as LAPC were included (7 men, 4 women; mean age: 61.1±8.6 years). The algorithm of CRT was as following: the radiotherapy dose was 50.4 Gy/28Fx with S-1 40 mg bid orally taken in radiotherapy day. Conventional ultrasound scan and CEUS were performed before and 4 weeks after CRT. All ultrasound examinations were performed by an ACUSON Oxana 2 ultrasound equipment (Siemens Medical Solutions, Germany) with a C 6-1 convex array transducer (1-6 MHz). Time intensity curves (TICs) were generated in the region of interests (ROIs) both in LAPC lesions and in its surrounding pancreas parenchyma by SonoLiver software (TOMTEC Imaging Systems). Quantitative perfusion parameters including maximum intensity (MI), rise time (RT), mean transit time (mTT) and time to peak (TTP) were analyzed and compared before and after CRT.

RESULTS

No significant difference could be found by conventional B mode ultrasound scan after CRT. TICs of CEUS showed lower ascending and descending slopes rate after CRT. Among all perfusion quantitative parameters, MI decreased significantly after CRT (42.1±18.8% vs 27.8±17.2%, P < 0.05).

CONCLUSIONS

Depending on its unique advantages as non-radiation, effective and convenient, D-CEUS analysis and quantitative parameters, particularly MI, has potential application value in following up of the CRT treatment response in LAPC patients.

Assessing Chemotherapeutic Response in Pancreatic Ductal Adenocarcinoma: Histogram Analysis of Iodine Concentration and CT Number in Single-Source Dual-Energy CT

OBJECTIVE

The objective of this study was to evaluate the feasibility of histographic analysis of iodine concentration (IC) and CT number on single-source dual-energy CT (DECT) to assess response to first-line chemotherapy in patients with pancreatic ductal adenocarcinoma (PDAC) who received first-line chemotherapy but not radiation therapy.

SUBJECTS AND METHODS

This prospective study was approved by our institutional review board, and patients gave written informed consent. Sixty consecutive patients with PDAC undergoing first-line chemotherapy underwent DECT during the pancreatic parenchymatous phase (PPP) and the equilibrium phase (EP). The IC and CT number of PDAC were measured using PPP and EP iodine-based material decomposition and monochromatic images (65 keV), respectively. Histographic parameters for the IC and CT number of PDACs were obtained, and differences in mean IC (ΔIC) and CT number (ΔHU) between the PPP and the EP were calculated. These parameters were then compared between the response (partial response or stable disease) and nonresponse (progressive disease) groups.

RESULTS

Among the histographic parameters, the kurtosis of IC during the PPP (p = 0.018) and ΔIC (p = 0.0004) were identified as significant for differentiating between the two groups. IC diagnostic factor was calculated using the following coefficients of logistic regression analysis: 0.52 - (1.45 × kurtosis of IC during PPP) + (0.69 × ΔIC). The sensitivity, specificity, and area under the ROC curve for differentiating between the two groups were 97.7%, 70.6%, and 0.889, respectively.

CONCLUSION

The IC diagnostic factor is a potential biomarker for assessing chemotherapeutic response in patients with PDAC.

Pictorial review of vascular involvement and complex vascular reconstructions in borderline to minimally advanced pancreatic malignancies

PURPOSE

To review borderline resectability criteria for pancreatic malignancies, show examples of few surgically treated minimally advanced pancreatic malignancies, discuss various complex vascular reconstructions, and highlight the imaging appearances.

BACKGROUND

Often aggressive surgical approaches are used to treat borderline to minimally advanced pancreatic malignancies in specialist centers. As abdominal radiologists it is essential to have up-to-date knowledge to distinguish such tumors with accuracy and also be well versed with the various vascular reconstructions used in such surgeries.

IMAGING FINDINGS

We will show various examples of resected borderline resectable and minimally advanced pancreatic malignancies, highlight crucial vascular involvements, describe various types of advanced vascular reconstructions, and review their standard imaging appearances. We will also briefly describe the vascular complications and highlight the importance of imaging surveillance in early post-operative period.

CONCLUSIONS

It is essential for abdominal radiologists in specialist centers where aggressive surgical approaches are used to have accurate knowledge to assess vascular involvement in pancreatic malignancies and equally to recognize and assess vascular reconstructions on imaging after complex surgeries.

Management of unresectable, locally advanced pancreatic adenocarcinoma

The diagnosis of unresectable locally advanced pancreatic adenocarcinoma (LAPC) requires confirmation, through imaging tests, of the unfeasibility of achieving a complete surgical resection, in the absence of metastatic spread. The increase in overall survival (OS), together with an appropriate symptom management is the therapeutic target in LAPC, maintaining an acceptable quality of life and, if possible, increasing the time until the appearance of metastasis. Chemoradiation (CRT) improves OS compared to best support treatment or radiotherapy (RT) but with greater toxicity. No significant increase in OS has been achieved with CRT when compared to chemotherapy (QT) alone in patients without disease progression after four months of treatment with QT. However, a significantly better local control, that is, a significant increase in the time to disease progression was associated with this approach. The greater effectiveness of the schemes FOLFIRINOX and gemcitabine (Gem) + Nab-paclitaxel compared to gemcitabine alone, has been extrapolated from metastatic disease to LAPC, representing a possible alternative for patients with good performance status (ECOG 0-1). In the absence of randomized clinical trials, Gem is the standard treatment in LAPC. If disease control is achieved after 4-6 cycles of QT, the use of CRT for consolidation can be considered an option vs QT treatment maintenance. Capecitabine has a better toxicity profile and effectiveness compared to gemcitabine as a radiosensitizer. After local progression, and without evidence of metastases, treatment with RT or CRT, in selected patients, can support to maintain the regional disease control.

EGFR-targeted gelatin nanoparticles for systemic administration of gemcitabine in an orthotopic pancreatic cancer model

In this study, we have formulated redox-responsive epidermal growth factor receptor (EGFR)-targeted type B gelatin nanoparticles as a targeted vector for systemic delivery of gemcitabine therapy in pancreatic cancer. The gelatin nanoparticles were formed by ethanol-induced desolvation process to encapsulate the bound drug. The surface of the nanoparticles was decorated either with poly(ethylene glycol) (PEG) chains to impart enhanced circulation time or with EGFR targeting peptide to confer target specificity. Our in vitro studies in Panc-1 human pancreatic ductal adenocarcinoma cells confirm that gemcitabine encapsulated in EGFR-targeted gelatin nanoparticles, released through disulfide bond cleavage, had a significantly improved cytotoxic profile. Further, the in vivo anticancer activity was evaluated in an orthotopic pancreatic adenocarcinoma tumor bearing SCID beige mice, which confirmed that EGFR-targeted gelatin nanoparticles could efficiently deliver gemcitabine to the tumor leading to higher therapeutic benefit as compared to the drug in solution.

FROM THE CLINICAL EDITOR

The treatment of pancreatic cancer remains unsatisfactory, with an average 5-year survival of less than 5%. New treatment modalities are thus urgently needed. In this study, the authors presented their formulation of redox-responsive epidermal growth factor receptor (EGFR)-targeted type B gelatin nanoparticles as a carrier for gemcitabine. In-vitro and in-vivo experiments showed encouraging results. It is hoped that the findings would provide a novel and alternative drug delivery platform for the future.