The Use of MR-Guided Radiation Therapy for Pancreatic Cancer

Moving From the Background Toward the Spotlight: A Critical Review of Radiation Therapy for Locally Advanced Pancreas Cancer

Radiation therapy (RT) for locally advanced pancreatic cancer (LAPC) continues to be controversial. Advances in both systemic therapy and RT techniques have changed the landscape of LAPC management in recent years. Clinical outcomes of ablative RT have been encouraging, and randomized clinical trials may clarify the role of RT for LAPC. We present a contemporary critical review of key aspects regarding optimal patient selection, radiation dose escalation techniques, novel radiosensitizers and radioprotectors, and treatment response assessment for LAPC.

Critical Review: Real-Time Dose-Guided Radiation Therapy

Dramatic strides have been made in real-time adaptive radiation therapy, where treating single tumors as dynamic but rigid bodies has demonstrated a halving of toxicities for prostate cancer. However, the human body is much more complex than a rigid body. This review explores the ongoing development and future potential of dose-guided radiation therapy, where the three core process steps of volumetric imaging of the patient, dose accumulation, and dose-guided treatment adaptation occur quasi-continuously during treatment, fully accounting for the complexity of the dynamic human body. The clinical evidence supporting real-time adaptive radiation therapy was reviewed. The foundational studies, status, and potential of real-time volumetric imaging using both x-ray and magnetic resonance imaging technology were described. The development of real-time dose accumulation to the dynamic patient was evaluated, and a method to measure real-time dose delivery was assessed. The growth of real-time treatment adaptation was examined. Literature demonstrates continued improvements in patient outcomes because the treatment becomes more conformal to the dynamic patient. Real-time volumetric imaging using both x-ray and magnetic resonance imaging technology is poised for broader implementation. Real-time dose accumulation has demonstrated clinical feasibility, with approximations made to achieve real-time operation. Real-time treatment adaptation to deforming targets and multiple targets has been experimentally demonstrated. Tying together the inputs of the real-time volumetric anatomy and dose accumulation is real-time treatment adaptation that uses the available degrees of freedom to optimize the dose delivered to the patient, maximizing the treatment intent. Opportunities exist for artificial intelligence to accelerate the application of dose-guided radiation therapy to broader patient use. In summary, the emerging field of real-time dose-guided radiation therapy has the potential to significantly improve patient outcomes. The advances are primarily software-driven and therefore could be widely available and cost-effective upgrades to improve imaging and targeting cancer.

Comprehensive insights into pancreatic cancer treatment approaches and cutting-edge nanocarrier solutions: from pathology to nanomedicine

Pancreatic cancer is one of the most lethal malignancies worldwide. It is characterized by poor prognosis, high mortality, and recurrence rates. Various modifiable and non-modifiable risk factors are associated with pancreatic cancer incidence. Available treatments for pancreatic cancer include surgery, chemotherapy, radiotherapy, photodynamic therapy, supportive care, targeted therapy, and immunotherapy. However, the survival rates for PC are very low. Regrettably, despite efforts to enhance prognosis, the survival rate of pancreatic cancer remains relatively low. Therefore, it is essential to investigate new approaches to improve pancreatic cancer treatment. By synthesizing current knowledge and identifying existing gaps, this article provides a comprehensive overview of risk factors, pathology, conventional treatments, targeted therapies, and recent advancements in nanocarriers for its treatment, along with various clinical trials and patents that justify the safety and efficacy of innovative carriers for drug delivery systems. Ultimately, this review underscores the potential of these innovative formulations to improve outcomes and contribute significantly to the advancement of Pancreatic Cancer treatment. Together, these insights highlight nano-formulations as a promising frontier for effectively treating Pancreatic Cancer.

NRG Oncology International Consensus Contouring Atlas on Target Volumes and Dosing Strategies for Dose-Escalated Pancreatic Cancer Radiation Therapy

PURPOSE

Dose-escalated radiation therapy is increasingly used in the treatment of pancreatic cancer; however, approaches to target delineation vary widely. We present the first North American cooperative group consensus contouring atlas for dose-escalated pancreatic cancer radiation therapy.

METHODS AND MATERIALS

An expert international panel comprising 15 radiation oncologists, 2 surgeons, and 1 radiologist was recruited. Participants used MimCloud software to contour high- and low-risk clinical target volumes (CTVs) on 3 pancreatic cancer cases: a borderline resectable head tumor, a locally advanced head tumor, and a medically inoperable tail tumor. Simultaneous Truth and Performance Level Estimation volumes were created, and contours were analyzed using Dice similarity coefficients.

RESULTS

The contoured gross tumor volume for the borderline head, locally advanced head, and unresectable tail tumor cases were 156.7, 58.2, and 9.0 cc, respectively, and the Dice similarity coefficients (SD) for the high- and low-risk CTV ranged from 0.45 to 0.82. Consensus volumes were agreed upon by authors. High-risk CTVs comprised the tumor plus abutting vessels. Low-risk CTVs started superiorly at (tail and distal body tumors) or 1 cm above (head, neck and proximal body tumors) the celiac takeoff and extended inferiorly to the superior mesenteric artery at the level of the first jejunal takeoff. For head, neck, and proximal body tumors, the lateral volume encompassed the entire pancreas head and 5 to 10 mm around the celiac, superior mesenteric artery, superior mesenteric vein, including the common hepatic artery and medial portal vein, consistent with a "Triangle" volume-based approach. For distal body and tail tumors, the entire tail was included, along with the splenic vessels and the takeoffs of celiac artery.

CONCLUSIONS

Through multidisciplinary collaboration, we created consensus contouring guidelines for dose-escalated pancreatic cancer radiation therapy. These volumes include not only gross disease, but also routine elective coverage, and can be used to standardize practice for future trials seeking to define the role of dose-escalated radiation therapy in pancreatic cancer.

Engineering Radiocatalytic Nanoliposomes with Hydrophobic Gold Nanoclusters for Radiotherapy Enhancement

Chemoradiation therapy is on the forefront of pancreatic cancer care, and there is a continued effort to improve its safety and efficacy. Liposomes are widely used to improve chemotherapy safety, and may accurately deliver high-Z element- radiocatalytic nanomaterials to cancer tissues. In this study, the interaction between X-rays and long-circulating nanoliposome formulations loaded with gold nanoclusters is explored in the context of oxaliplatin chemotherapy for desmoplastic pancreatic cancer. Hydrophobic gold nanoclusters stabilized with dodecanethiol (AuDDT) are efficiently incorporated in nanoliposomal bilayers. AuDDT-nanoliposomes significantly augmented radiation-induced •OH production, which is most effective with monochromatic X-rays at energies that exceed the K-shell electron binding energy of Au (81.7 keV). Cargo release assays reveal that AuDDT-nanoliposomes can permeabilize lipid bilayers in an X-ray dose- and formulation-dependent manner. The radiocatalytic effect of AuDDT-nanoliposomes significantly augments radiotherapy and oxaliplatin-chemoradiotherapy outcomes in 3D pancreatic microtumors. The PEGylated AuDDT-nanoliposomes display high tumor accumulation in an orthotopic mouse model of pancreatic cancer, showing promise for nanoliposomes as carriers for radiocatalytic nanomaterials. Altogether, compelling proof for chemo-radiation dose-enhancement using AuDDT-nanoliposomes is presented. Further improving the nanoliposomal loading of high-Z elements will advance the safety, efficacy, and translatability of such chemoradiation dose-enhancement approaches.

Daily Diagnostic Quality Computed Tomography-on-Rails (CTOR) Image Guidance for Abdominal Stereotactic Body Radiation Therapy (SBRT)

BACKGROUND/OBJECTIVES

Stereotactic body radiation therapy (SBRT) for abdominal targets faces a variety of challenges, including motion caused by the respiration and digestion and a relatively poor level of contrast between the tumor and the surrounding tissues. Breath-hold treatments with computed tomography-on-rails (CTOR) image guidance is one way of addressing these challenges, allowing for both the tumor and normal tissues to be well-visualized. Using isodose lines (IDLs) from CT simulations as a guide, the anatomical information can be used to shift the alignment or trigger a replan, such that normal tissues receive acceptable doses of radiation.

METHODS

This study aims to describe the workflow involved when using CTOR for pancreas and liver SBRT and demonstrates its effectiveness through several case studies.

RESULTS

In these case studies, using the anatomical information gained through diagnostic-quality CT guidance to make slight adjustments to the alignment, resulted in reductions in the maximum dose to the stomach.

CONCLUSIONS

High-quality imaging, such as CTOR, and the use of IDLs to estimate the doses to OARs, enable the safe delivery of SBRT, without the added complexity and resource commitment required by daily online adaptive planning.

Targeted Nanoparticle-Based Diagnostic and Treatment Options for Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC), one of the deadliest cancers, presents significant challenges in diagnosis and treatment due to its aggressive, metastatic nature and lack of early detection methods. A key obstacle in PDAC treatment is the highly complex tumor environment characterized by dense stroma surrounding the tumor, which hinders effective drug delivery. Nanotechnology can offer innovative solutions to these challenges, particularly in creating novel drug delivery systems for existing anticancer drugs for PDAC, such as gemcitabine and paclitaxel. By using customization methods such as incorporating conjugated targeting ligands, tumor-penetrating peptides, and therapeutic nucleic acids, these nanoparticle-based systems enhance drug solubility, extend circulation time, improve tumor targeting, and control drug release, thereby minimizing side effects and toxicity in healthy tissues. Moreover, nanoparticles have also shown potential in precise diagnostic methods for PDAC. This literature review will delve into targeted mechanisms, pathways, and approaches in treating pancreatic cancer. Additional emphasis is placed on the study of nanoparticle-based delivery systems, with a brief mention of those in clinical trials. Overall, the overview illustrates the significant advances in nanomedicine, underscoring its role in transcending the constraints of conventional PDAC therapies and diagnostics.