Endoscopic ultrasound-guided oncologic therapy for pancreatic cancer. Diagn Ther Endosc. 2013;2013:157581. [PMID: 23533319 PMCID: PMC3595706 DOI: 10.1155/2013/157581]

Role of Therapeutic Endoscopic Ultrasound in Management of Pancreatic Cancer: An Endoscopic Oncologist Perspective

Pancreatic cancer is a highly lethal disease with an aggressive clinical course. Patients with pancreatic cancer are usually asymptomatic until significant progression of their disease. Additionally, there are no effective screening guidelines for pancreatic cancer in the general population. This leads to a delay in diagnosis and treatment, resulting in poor clinical outcomes and low survival rates. Endoscopic Ultrasound (EUS) is an indispensable tool for the diagnosis and staging of pancreatic cancer. In the modern era, with exponential advancements in technology and device innovation, EUS is also being increasingly used in a variety of therapeutic interventions. In the context of pancreatic cancer where therapies are limited due to the advanced stage of the disease at diagnosis, EUS-guided interventions offer new and innovative options. Moreover, due to their minimally invasive nature and ability to provide real-time images for tumor localization and therapy, they are associated with fewer complication rates compared to conventional open and laparoscopic approaches. In this article, we detail the most current and important therapeutic applications of EUS for pancreatic cancer, namely EUS-guided Fine Needle Injections, EUS-guided Radiotherapy, and EUS-guided Ablations. Furthermore, we also discuss the feasibility and safety profile of each intervention in patients with pancreatic cancer to provide gastrointestinal medical oncologists, radiation and surgical oncologists, and therapeutic endoscopists with valuable information to facilitate patient discussions and aid in the complex decision-making process.

Role of endoscopic ultrasonography guided fiducial marker placement in gastrointestinal cancer

PURPOSE OF REVIEW

Dose escalation radiation therapy such as those delivered by stereotactic body radiation therapy (SBRT) has shown to improve local disease control in multiple types of malignancies. This requires fiducial placement to improve accuracy of treatment and avoid adverse events to adjacent radiosensitive organs during respiration phases. The purpose of this review is to provide updates of recent high-quality articles related to endoscopic ultrasonography (EUS)-guided fiducial placement for gastrointestinal malignancies, particularly in pancreatic cancer, which is expected to be the second leading cause of cancer-related deaths in the USA within this decade.

RECENT FINDINGS

A recent systematic review and meta-analysis has shown that EUS-guided fiducial placement for gastrointestinal malignancies has excellent technical success and safety profile. Comparative studies of most commercially available fiducial types via a 22-gauge needle system showed that a 0.035 mm diameter and 10 mm long gold fiducial with coiled configuration, hollow core and external helical design might be favoured due to its most balanced performance of visibility, artifact and migration.

SUMMARY

A fine balance of performance characteristics of fiducials should be discussed with radiation oncologists to select a suitable and preferred type of fiducials. The comparative studies of other newly developed platinum fiducials and liquid fiducial are pending.

Endoscopic ultrasound in pancreatic cancer treatment: Facts and hopes

Pancreatic ductal adenocarcinoma is one of the most common causes of cancer-related deaths. Since most patients present with advanced disease, its prognosis is dismal. New and more effective therapeutic strategies are needed. Endoscopic ultrasound is currently an indispensable tool for the diagnosis and staging of pancreatic ductal adenocarcinoma. In recent years, endoscopic ultrasound has evolved to become also a therapeutic procedure. On one hand, the role of endoscopic ultrasound in the management of pancreatic cancer-related symptoms (pain, obstructive jaundice, and gastric outlet obstruction) is now well established. On the other hand, its use as a mean to the delivery of anti-tumor therapies (injecting anti-tumor agents, assisting in radiotherapy, and guiding ablative therapies) is still mostly experimental, despite growing evidence supporting its feasibility, safety and efficacy.

EUS-guided fiducial placement for GI malignancies: a systematic review and meta-analysis

BACKGROUND AND AIMS

Image-guided radiotherapy (IGRT) allows the delivery of radiation with high precision to a target lesion while minimizing toxicity to surrounding tissues. EUS provides excellent visualization of GI tumors and consequently is being used for fiducial placement with increased frequency. Our goal was to perform a systematic review and meta-analysis of studies evaluating the technical aspects, safety, and efficacy of EUS fiducial placement for IGRT in GI malignancies.

METHODS

A systematic literature search was carried out in the following databases: Medline, PubMed, Embase, Web of Science, and Cochrane Library, using Medical Subject Headings terms combined with text words. A random effects model was used to determine pooled proportions of technical success, migration, and adverse event rates. Heterogeneity was assessed using the I² statistic. Publication bias was assessed visually using a funnel plot and by the Begg and Egger tests.

RESULTS

Nine full articles and 5 abstracts reporting on 1155 patients, 49% from a single study by Dhadham et al, were included in the meta-analysis. The pooled rate of technical success was 98% (95% confidence interval [CI], 96-99). Moderate heterogeneity (I² = 34.18) was present, which appeared to be due to variable sample sizes. Publication bias was present, suggesting that studies with less-substantial outcomes may have not been reported (Begg test, P = .87; Egger test, P < .01). Pooled rates for fiducial migration and adverse events were 3% (95% CI, 1.0-8.0) and 4% (95% CI, 3-7), respectively.

CONCLUSIONS

Our meta-analysis showed that EUS-guided insertion of gold fiducials for IGRT is technically feasible and safe. Further controlled studies assessing its long-term effectiveness in GI malignancies are needed.

[Endoscopic Treatment for Pancreatic Cystic Lesions]

The decision of the appropriate treatment for pancreatic cystic lesions (PCLs) is becoming increasingly important as the number of incidentally found PCLs increases. A range of modalities have been attempted because there has been an increasing demand for minimally invasive treatment for PCLs due to the large burden of a surgical resection. Endoscopic treatment using endoscopic ultrasonography (EUS), a representative of minimally invasive therapy, can be categorized into two types: ablation therapy by the injection of drugs and topical thermal coagulative therapy through the high topical energy. A number of studies reported the feasibility and efficacy of these treatments; the most common is EUS-guided ablation for PCLS with ethanol alone or in combination with anticancer drugs. Although ablation therapies with drug injection have proven safety and feasibility, there is no consensus regarding the actual treatment effects and indications of these modalities. EUS-guided radiofrequency ablation was recently attempted as a representative method of local thermal coagulation, but further studies will be needed because of the lack of evidence of its feasibility and safety. In addition, a range of treatments for malignant tumors rather than PCLs have been attempted, such as EUS-guided photodynamic therapy, EUS-guided neodymium-doped yttrium aluminum garnet laser, and high-intensity focused ultrasound, based on the data from animal experiments. Through further study, endoscopic treatment is expected to become established as a useful treatment modality for PCLs.

Molecular targeting of cell-permeable peptide inhibits pancreatic ductal adenocarcinoma cell proliferation

Background

Chromosome 16 open reading frame 74 (C16orf74) is highly expressed in pancreatic ductal adenocarcinoma (PDAC) and is involved in cancer cell proliferation and invasion through binding to calcineurin (CN). Therefore, C16orf74 is a good target for the development of a PDAC treatment. A cell-permeable dominant-negative (DN) peptide that can inhibit the C16orf74/CN interaction was designed to examine whether this peptide can inhibit PDAC cell proliferation in vitro and in vivo.

Method

TheDN-C16orf74 peptide, which corresponds to the portion of C16orf74 that interacts with CN, was synthesized, and we assessed its anti-tumor activity in proliferation assays with human PDAC cells and the underlying molecular signaling pathway. Using an orthotopic xenograft model of PDAC, we treated mice intraperitoneally with phosphate-buffered saline (PBS), control peptide, or DN-C16orf74 and analyzed the tumor-suppressive effects.

Result

DN-C16orf74 inhibited the binding of C16orf74 to CN in an immunoprecipitation assay. DN-C16orf74 suppressed PDAC cell proliferation, and the level of suppression depended on the expression levels of C16orf74 in vitro. DN-C16orf74 also exhibited anti-tumor effects in orthotopic xenograft model. Furthermore, the tumor-suppressive effect was associated with inhibition of the phosphorylation of Akt and mTOR.

Conclusion

The cell-permeable peptide DN-C16orf74 has a strong anti-tumor effect against PDAC in vitro and in vivo.

Temperature feedback-controlled photothermal treatment with diffusing applicator: theoretical and experimental evaluations

To minimize thermal injury, the current study evaluated the real-time temperature monitoring with a proportional-integrative-derivative (PID) controller during 980-nm photothermal treatment with a radially-diffusing applicator. Both simulations and experiments demonstrated comparable thermal behaviors in temperature distribution and the degree of irreversible tissue denaturation. The PID-controlled application constantly maintained the pre-determined temperature of 353 K (steady-state error = < 1 K). Due to constant energy delivery, coagulation volumes linearly increased up to 1.04 ± 0.02 cm(3) with irradiation time. Integration of temperature feedback with diffuser-assisted photothermal treatments can provide a feasible therapeutic modality to treat pancreatic tumors in an effective manner.

Endoscopic ultrasound-fine needle injection for oncological therapy

The minimal invasiveness and precision of endoscopic ultrasound (EUS) has lead to both its widespread use as a diagnostic and staging modality for gastrointestinal and pancreaticobiliary malignancies, and to its expanding role as a therapeutic modality. EUS-guided celiac plexus neurolysis is now a well-accepted modality for palliation of pain in patients with pancreatic cancer. EUS-guided ablation, brachytherapy, fiducial marker placement, and antitumor agent injection have been described as methods of performing minimally invasive oncological therapy. EUS-fine needle injection may be performed as adjunctive, alternative, or palliative treatment. This review summarizes the studies to date that have described these methods. A literature search using the PubMed/MEDLINE databases was performed. While most published studies to date are limited with disappointing outcomes, the concept of a role of EUS in oncological therapy seems promising.

Role of endoscopic ultrasound in diagnosis and management of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is an aggressive tumor and a leading cause of cancer-related deaths globally. The mortality rate remains high despite many advances in treatment. HCC is frequently diagnosed late in its course due to lack of classical symptoms at earlier stages. Endoscopic ultrasound (EUS) has emerged as an important diagnostic tool for the diagnostic evaluation, staging, and treatment of gastrointestinal tract disorders. EUS-guided fine needle aspiration has been a valuable addition to EUS by being able to obtain tissue under direct visualization. Here, we review the potential role of EUS in the diagnosis and management of HCC. EUS seems to be a safe and reliable alternative method for obtaining tissue for diagnosis of liver cancer, especially for lesions that are inaccessible by traditional methods. EUS could play an important role in the diagnosis and management of HCC.

Using the Promise of Sonodynamic Therapy in the Clinical Setting against Disseminated Cancers

Sonodynamic therapy (SDT) is a form of ultrasound therapy in which specialized chemotherapeutic agents known as sonosensitizers are administered to increase the efficacy of ultrasound-mediated preferential damage of neoplastic cells. Multiple in vitro and in vivo studies have indicated that SDT has the ability to exhibit profound physical and chemical changes on cellular structure. As supportive as the data have been, assessment of this method at the clinical level has been limited to only solid tumors. Although SDT has shown efficacy against multiple adherent neoplastic cell lines, it has also shown particular promise with leukemia-derived cell lines. Potential procedures to administer SDT to leukemia patients are heating the appendages as ultrasound is applied to these areas (Heat and Treat), using an ultrasound probe to scan the body for malignant growths (Target and Destroy), and extracorporeal blood sonication (EBS) through dialysis. Each method offers a unique set of benefits and concerns that will need to be evaluated in preclinical mammalian models of malignancy before clinical examination can be considered.

Technical advances in endoscopic ultrasound-guided fiducial placement for the treatment of pancreatic cancer

Radiation therapy has an important role in the treatment of locally advanced or metastatic pancreatic cancer and can be used alone or in conjunction with surgery and/or systemic chemotherapy. Because of the challenge of delivering an accurate and optimal radiation dose, image-guided radiation therapy can be used to improve targeting. Fiducial markers can be placed in the tumor and used for localization in patients undergoing image-guided radiation therapy. The safety and feasibility of endoscopic ultrasound (EUS)-guided placement of fiducials has been assessed and reported for the management of pancreatic cancer. We herein review the technique, efficacy, and safety profile of EUS-guided fiducial placement. In addition, we highlight recent advances and technological upgrades in EUS-guided fiducial delivery systems for pancreatic cancer most relevant to practicing gastroenterologists and interventional endoscopists.

Endoscopic Ultrasound-Guided Treatment of Pancreatic Cystic and Solid Masses

Pancreatic tumor is one of the most difficult diseases to diagnose and treat because of its anatomical location and characteristics. Recently, there have been several innovative trials on the treatment of pancreatic tumors using endoscopic ultrasound (EUS) because it allows selective access to the difficult to reach target organ along the gastrointestinal tract and can differentiate vessels by color Doppler. Among these trials, several have investigated EUS-guided ethanol lavage with or without paclitaxel for pancreatic cystic tumors. These studies show a 33% to 79% complete resolution rate with a favorable safety profile. Compared to EUS-guided ethanol lavage for pancreatic cystic tumors, EUS-guided radiofrequency ablation is considered a less invasive treatment method for pancreatic cancer. Although there are still several difficulties and concerns about complications, one clinical study reported 72.8% feasibility with favorable safety, and therefore, we anticipate the results of ongoing studies with these new less invasive techniques.

The role of therapeutic endoscopic ultrasound now and for the future

Therapeutic endoscopic ultrasound (EUS) became possible after the advent of the linear echoendoscope and the EUS guided fine needle aspiration. Over the past two decades, the indications for therapeutic EUS have expanded and evidence regarding its utility has been steadily accumulating. Randomized studies have shown EUS to be effective for cancer pain relief (celiac plexus neurolysis), pancreatic fluid collection drainage, and biliary drainage. Prospective studies have shown EUS-guided biliary drainage to be safe and effective in patients with failed ERCP. There is evidence to suggest that EUS is effective for pancreatic duct drainage, gallbladder drainage, and drainage of pelvic collections. EUS may also be useful for targeted cancer treatment via brachytherapy, radiofrequency ablation, or injection therapy. Therapeutic EUS is likely to play an increasingly important role in endoscopic therapy of gastrointestinal diseases in the near future.