Stereotactic body radiotherapy in the treatment of pancreatic cancer

Single-Fraction Stereotactic Ablative Body Radiotherapy for Primary and Extracranial Oligometastatic Cancers

Stereotactic ablative body radiotherapy (SABR) consists of delivering high doses of ionising radiation, typically across three to eight fractions with high precision and conformity. SABR has become increasingly commonplace throughout the last quarter of a century and is offered for the treatment of various primary and metastatic tumour types. Delivering SABR in a single fraction has arisen as an appealing possibility for several reasons. These include fewer hospital visits, greater patient convenience, improved sustainability and lower costs. However, these factors must be balanced against considerations such as toxicity, side-effects and, most importantly, progression-free and overall survival. In this review we seek to analyse the results of studies looking at the efficacy of single-fraction SABR for lung, prostate, renal and pancreas primary tumours, as well as oligometastases. The tumour type to be most widely treated with single-fraction SABR is lung, but its remit continues to expand. We also look at the biological rationale underpinning SABR and how this can be extended to single-fraction regimens. Finally, we turn our attention towards the future directions of SABR and specifically single-fraction regimens. These include the possibility of combining SABR with immunotherapy and technological advances in the field, which could serve to expand the scope of SABR. We conclude by summarising the current clinical studies of single-fraction SABR.

Dose Escalation for Pancreas SBRT: Potential and Limitations of using Daily Online Adaptive Radiation Therapy and an Iterative Isotoxicity Automated Planning Approach

Purpose

To determine the dosimetric limitations of daily online adaptive pancreas stereotactic body radiation treatment by using an automated dose escalation approach.

Methods and Materials

We collected 108 planning and daily computed tomography (CT) scans from 18 patients (18 patients × 6 CT scans) who received 5-fraction pancreas stereotactic body radiation treatment at MD Anderson Cancer Center. Dose metrics from the original non-dose-escalated clinical plan (non-DE), the dose-escalated plan created on the original planning CT (DE-ORI), and the dose-escalated plan created on daily adaptive radiation therapy CT (DE-ART) were analyzed. We developed a dose-escalation planning algorithm within the radiation treatment planning system to automate the dose-escalation planning process for efficiency and consistency. In this algorithm, the prescription dose of the dose-escalation plan was escalated before violating any organ-at-risk (OAR) dose constraint. Dose metrics for 3 targets (gross target volume [GTV], tumor vessel interface [TVI], and dose-escalated planning target volume [DE-PTV]) and 9 OARs (duodenum, large bowel, small bowel, stomach, spinal cord, kidneys, liver, and skin) for the 3 plans were compared. Furthermore, we evaluated the effectiveness of the online adaptive dose-escalation planning process by quantifying the effect of the interfractional dose distribution variations among the DE-ART plans.

Results

The median D_95% dose to the GTV/TVI/DE-PTV was 33.1/36.2/32.4 Gy, 48.5/50.9/40.4 Gy, and 53.7/58.2/44.8 Gy for non-DE, DE-ORI, and DE-ART, respectively. Most OAR dose constraints were not violated for the non-DE and DE-ART plans, while OAR constraints were violated for the majority of the DE-ORI patients due to interfractional motion and lack of adaptation. The maximum difference per fraction in D_95%, due to interfractional motion, was 2.5 ± 2.7 Gy, 3.0 ± 2.9 Gy, and 2.0 ± 1.8 Gy for the TVI, GTV, and DE-PTV, respectively.

Conclusions

Most patients require daily adaptation of the radiation planning process to maximally escalate delivered dose to the pancreatic tumor without exceeding OAR constraints. Using our automated approach, patients can receive higher target dose than standard of care without violating OAR constraints.

Brachytherapy via a depot of biopolymer-bound 131I synergizes with nanoparticle paclitaxel in therapy-resistant pancreatic tumours

Locally advanced pancreatic tumours are highly resistant to conventional radiochemotherapy. Here we show that such resistance can be surmounted by an injectable depot of thermally responsive elastin-like polypeptide (ELP) conjugated with iodine-131 radionuclides (131I-ELP) when combined with systemically delivered nanoparticle albumin-bound paclitaxel. This combination therapy induced complete tumour regressions in diverse subcutaneous and orthotopic mouse models of locoregional pancreatic tumours. 131I-ELP brachytherapy was effective independently of the paclitaxel formulation and dose, but external beam radiotherapy (EBRT) only achieved tumour-growth inhibition when co-administered with nanoparticle paclitaxel. Histological analyses revealed that 131I-ELP brachytherapy led to changes in the expression of intercellular collagen and junctional proteins within the tumour microenvironment. These changes, which differed from those of EBRT-treated tumours, correlated with the improved delivery and accumulation of paclitaxel nanoparticles within the tumour. Our findings support the further translational development of 131I-ELP depots for the synergistic treatment of localized pancreatic cancer.

Toll-like receptor 7/8 agonist R848 alters the immune tumor microenvironment and enhances SBRT-induced antitumor efficacy in murine models of pancreatic cancer

BACKGROUND

Stereotactic body radiotherapy (SBRT) has been increasingly used as adjuvant therapy in pancreatic ductal adenocarcinoma (PDAC), and induces immunogenic cell death, which leads to the release of tumor antigen and damage-associated molecular patterns. However, this induction often fails to generate sufficient response to overcome pre-existing tumor microenvironment (TME) immunosuppression. Toll-like receptor (TLR) 7/8 ligands, such as R848, can amplify the effect of tumor vaccines, with recent evidence showing its antitumor effect in pancreatic cancer by modulating the immunosuppressive TME. Therefore, we hypothesized that the combination of R848 and SBRT would improve local and systemic antitumor immune responses by potentiating the antitumor effects of SBRT and reversing the immunosuppressive nature of the PDAC TME.

METHODS

Using murine models of orthotopic PDAC, we assessed the combination of intravenous TLR7/8 agonist R848 and local SBRT on tumor growth and immune response in primary pancreatic tumors. Additionally, we employed a hepatic metastatic model to investigate if the combination of SBRT targeting only the primary pancreatic tumor and systemic R848 is effective in controlling established liver metastases.

RESULTS

We demonstrated that intravenous administration of the TLR7/8 agonist R848, in combination with local SBRT, leads to superior tumor control compared with either treatment alone. The combination of R848 and SBRT results in significant immune activation of the pancreatic TME, including increased tumor antigen-specific CD8+ T cells, decreased regulatory T cells, and enhanced antigen-presenting cells maturation, as well as increased interferon gamma, granzyme B, and CCL5 along with decreased levels of interleukin 4 (IL-4), IL-6, and IL-10. Importantly, the combination of SBRT and systemic R848 also resulted in similar immunostimulatory changes in liver metastases, leading to improved metastatic control. CD8+ T cell depletion studies highlighted the necessity of these effector cells at both the local and hepatic metastatic sites. T cell receptor (TCR) clonotype analysis indicated that systemic R848 not only diversified the TCR repertoire but also conditioned the metastatic foci to facilitate entry of CD8+ T cells generated by SBRT therapy.

CONCLUSIONS

These findings suggest that systemic administration of TLR7/8 agonists in combination with SBRT may be a promising avenue for metastatic PDAC treatment.

Evaluation of the impact of teaching on delineation variation during a virtual stereotactic ablative radiotherapy contouring workshop

Introduction:

Variation in delineation of target volumes/organs at risk (OARs) is well recognised in radiotherapy and may be reduced by several methods including teaching. We evaluated the impact of teaching on contouring variation for thoracic/pelvic stereotactic ablative radiotherapy (SABR) during a virtual contouring workshop.

Materials and methods:

Target volume/OAR contours produced by workshop participants for three cases were evaluated against reference contours using DICE similarity coefficient (DSC) and line domain error (LDE) metrics. Pre- and post-workshop DSC results were compared using Wilcoxon signed ranks test to determine the impact of teaching during the workshop.

Results:

Of 50 workshop participants, paired pre- and post-workshop contours were available for 21 (42%), 20 (40%) and 22 (44%) participants for primary lung cancer, pelvic bone metastasis and pelvic node metastasis cases, respectively. Statistically significant improvements post-workshop in median DSC and LDE results were observed for 6 (50%) and 7 (58%) of 12 structures, respectively, although the magnitude of DSC/LDE improvement was modest in most cases. An increase in median DSC post-workshop ≥0·05 was only observed for GTVbone, IGTVlung and SacralPlex, and reduction in median LDE > 1 mm was only observed for GTVbone, CTVbone and SacralPlex. Post-workshop, median DSC values were >0·7 for 75% of structures. For 92% of the structures, post-workshop contours were considered to be acceptable or within acceptable variation following review by the workshop faculty.

Conclusions:

This study has demonstrated that virtual SABR contouring training is feasible and was associated with some improvements in contouring variation for multiple target volumes/OARs.

An Evaluation of Total Internal Motions of Locally Advanced Pancreatic Cancer during SABR Using Calypso® Extracranial Tracking, and Its Possible Clinical Impact on Motion Management

(1) Background: the aims of this study were to determine the total extent of pancreatic cancer’s internal motions, using Calypso^® extracranial tracking, and to indicate possible clinical advantages of continuous intrafractional fiducial-based tumor motion tracking during SABR. (2) Methods: thirty-four patients were treated with SABR for LAPC using Calypso^® for motion management. Planning MSCTs in FB and DBH, and 4D-CTs were performed. Using data from Calypso^® and 4D-CTs, the movements of the lesions in the CC, AP and LR directions, as well as the volumes of the 4D-CT-based ITV and the volumes of the Calypso^®-based ITV were compared. (3) Results: significantly larger medians of tumor excursions were found with Calypso^® than with 4D-CT: CC: 29 mm (p < 0.001); AP: 14 mm (p < 0.001) and LR: 11 mm (p < 0.039). The median volume of the Calypso^®-based ITV was significantly larger than that of the 4D-CT based ITV (p < 0.001). (4) Conclusion: beside known respiratory-induced internal motions, pancreatic cancer seems to have significant additional motions which should be considered during respiratory motion management. Only direct and continuous intrafractional fiducial-based motion tracking seems to provide complete coverage of the target lesion with the prescribed isodose, which could allow for safe tumor dose escalation.

Response of Canine Soft Tissue Sarcoma to Stereotactic Body Radiotherapy

Canine soft tissue sarcoma (STS) has served as a preclinical model for radiation, hyperthermia, experimental therapeutics, and tumor microenvironmental research for decades. Stereotactic body radiotherapy (SBRT) demonstrates promising results for the control of various tumors in human and veterinary medicine; however, there is limited clinical data for the management of STS with SBRT. In this retrospective study, we aimed to define overall efficacy and toxicity of SBRT for the treatment of macroscopic canine STS to establish this preclinical model for comparative oncology research. Fifty-two canine patients met inclusion criteria. Total radiation dose prescribed ranged from 20-50 Gy delivered in 1-5 fractions. Median progression-free survival time (PFST) was 173 days and overall survival time (OST) 228 days. Best overall response was evaluable in 46 patients, with 30.4% responding to treatment (complete response n = 3; partial response n = 11). For responders, OST significantly increased to 475 days vs. 201 days (P = 0.009). Prognostic factors identified by multivariable Cox regressions included size of tumor and metastasis at presentation. Dogs were 3× more likely to progress (P = 0.009) or 3.5× more likely to experience death (P = 0.003) at all times of follow up if they presented with metastatic disease. Similarly, every 100-cc increase in tumor volume resulted in a 5% increase in the risk of progression (P = 0.002) and death (P = 0.001) at all times of follow up. Overall, 30.8% of patients developed acute toxicities, 7.7% grade 3; 28.8% of patients developed late toxicities, 11.5% grade 3. Increased dose administered to the skin significantly affected toxicity development. SBRT serves as a viable treatment option to provide local tumor control for canine macroscopic STS, particularly those with early-stage disease and smaller tumors. The results of this study will help to define patient inclusion criteria and to set dose limits for preclinical canine STS trials involving SBRT.

Diffusion-Weighted and Dynamic Contrast-Enhanced MRI Derived Imaging Metrics for Stereotactic Body Radiotherapy of Pancreatic Ductal Adenocarcinoma: Preliminary Findings

We aimed to assess longitudinal changes in quantitative imaging metric values obtained from diffusion-weighted (DW-) and dynamic contrast-enhanced magnetic resonance imaging (DCE)-MRI at pre-treatment (TX[0]), immediately after the first fraction of stereotactic body radiotherapy (D1-TX[1]), and 6 weeks post-TX (Post-TX[2]) in patients with pancreatic ductal adenocarcinoma. Ten enrolled patients (n = 10) underwent DW- and DCE-MRI examinations on a 3.0 T scanner. The apparent diffusion coefficient, ADC (mm²/s), was derived from DW imaging data using a monoexponential model. The tissue relaxation rate, R _1t, time-course data were fitted with a shutter-speed model, which provides estimates of the volume transfer constant, K ^trans (min^-1), extravascular extracellular volume fraction, v_e , and mean lifetime of intracellular water protons, τ _i (seconds). Wilcoxon rank-sum test compared the mean values, standard deviation, skewness, kurtosis, and relative percentage (r, %) changes (Δ) in ADC, K ^trans, v_e , and τ _i values between the magnetic resonance examinations. rADC_Δ2-0 values were significantly greater than rADC_Δ1-0 values (P = .009). rK ^trans _Δ2-0 values were significantly lower than rK ^trans _Δ1-0 values (P = .048). rv_{e Δ2-1} and rv_eΔ2-0 values were significantly different (P = .016). rτ _{i Δ2-1} values were significantly lower than rτ _{i Δ2-0} values (P = .008). For group comparison, the pre-TX mean and kurtosis of ADC (P = .18 and P = .14), skewness and kurtosis of K ^trans values (P = .14 for both) showed a leaning toward significant difference between patients who experienced local control (n = 2) and failed early (n = 4). DW- and DCE-MRI-derived quantitative metrics could be useful biomarkers to evaluate longitudinal changes to stereotactic body radiotherapy in patients with pancreatic ductal adenocarcinoma.

Role of FOLFIRINOX and chemoradiotherapy in locally advanced and borderline resectable pancreatic adenocarcinoma: update of the AGEO cohort

BACKGROUND

FOLFIRINOX has shown promising results in locally advanced (LAPA) or borderline resectable (BRPA) pancreatic adenocarcinoma. We report here a cohort of patients treated with this regimen from the AGEO group.

METHODS

This is a retrospective multicentre study. We included all consecutive patients with non-pre-treated LAPA or BRPA treated with FOLFIRINOX.

RESULTS

We included 330 patients (57.9% male, 65.4% <65 years, 96.4% PS <2). Disease was classified as BRPA in 31.1% or LAPA in 68.9%. Objective response rate with FOLFIRINOX was 29.5% and stable disease 51%. Subsequent CRT was performed in 46.4% of patients and 23.9% had curative intent surgery. Resection rates were 42.1% for BRPA and 15.5% for LAPA. Main G3/4 toxicities were fatigue (15%), neutropenia (12%) and neuropathy (G2/3 35%). After a median follow-up of 26.7 months, median OS (mOS) and PFS were 21.4 and 12.4 months, respectively. For patients treated by FOLFIRINOX alone, or FOLFIRINOX followed by CRT, or FOLFIRINOX + /- CRT + surgery, mOS was 16.8 months, 21.8 months and not reached, respectively (p < 0.0001).

CONCLUSIONS

FOLFIRINOX for LAPA and BRPA seems to be effective with a manageable toxicity profile. These promising results in "real-life" patients now have to be confirmed in a Phase 3 randomised trial.

Clinical Effects of Stereotactic Body Radiation Therapy Targeting the Primary Tumor of Liver-Only Oligometastatic Pancreatic Cancer

Aim

To investigate the efficacy and safety of stereotactic body radiotherapy (SBRT) targeting the primary tumor for liver-only oligometastatic pancreatic cancer.

Methods

We compared the efficacy and safety of SBRT plus chemotherapy with chemotherapy alone in patients with liver-only oligometastatic pancreatic cancer. The populations were balanced by propensity score-weighted and propensity score-matched analyses based on baseline variables. The primary outcome was overall survival (OS). The secondary outcomes included progression free survival (PFS), local progression, metastatic progression and symptomatic local control.

Results

This is a retrospective study of 89 pancreatic cancer patients with liver-only oligometastasis. Overall, 34 (38.2%) and 55 (61.8%) patients received SBRT plus chemotherapy and chemotherapy alone, respectively. After propensity score matching, 1-year OS rate was 34.0% (95%CI, 17.8-65.1%) in the SBRT plus chemotherapy group and 16.5% (95%CI, 5.9-46.1%) in chemotherapy alone group (P=0.115). The 6-month PFS rate was 29.4% (95%CI, 15.4-56.1) in SBRT plus chemotherapy and 20.6% (95%CI, 8.8-48.6) in chemotherapy alone group (P=0.468), respectively. Further subgroup analysis indicated that the addition of SBRT improved OS in patients with primary tumor located in the head of pancreas (stratified HR, 0.28; 95% CI, 0.09 to 0.90) or good performance status (stratified HR, 0.24; 95% CI, 0.07 to 0.86). In terms of disease control, SBRT delayed local progression of pancreas (P=0.008), but not distant metastatic progression (P=0.56). Besides, SBRT offered significant abdominal/back pain relief (P=0.016) with acceptable toxicities.

Conclusions

The addition of SBRT to chemotherapy in patients with liver-only oligometastatic pancreatic cancer improves the OS of those with primary tumor located in the head of pancreas or good performance status. In addition, it is a safe and effective method for local progression control and local symptomatic palliation in patients with metastatic pancreatic cancer.

Dosimetric effect of the intestinal gas of online adaptive stereotactic body radiotherapy on target and critical organs without online electron density correction for pancreatic cancer

OBJECTIVE

This study aimed to assess the dosimetric effect of intestinal gas of stereotactic magnetic resonance (MR)-guided adaptive radiation therapy (SMART) on target and critical organs for pancreatic cancer without online electron density correction (EDC).

METHODS

Thirty pancreatic cancer patients who underwent online SMART were selected for this study. The treatment time of each stage and the total treatment time were recorded and analyzed. The concerned dose-volume parameters of target and organs-at-risk (OAR) were compared with and without an intestinal gas EDC using the Wilcoxon-signed rank test. Analysis items with p value < 0.05 were considered statistically significant. The relationships between dosimetric differences and intestinal gas volume variations were investigated using the Spearman test.

RESULTS

The average treatment time was 82 min, and the average EDC time was 8 min, which accounted for 10% of the overall treatment time. There were no significant differences in CTV (GTV), PTV, bowel, stomach, duodenum, and skin (p > 0.05) with respect to dose volume parameters. For the D_max of gastrointestinal organs (p = 0.03), the mean dose of the liver (p = 0.002) and kidneys (p = 0.03 and p = 0.04 for the left and right kidneys, respectively), there may be a risk of slight overestimation compared with EDC, and for the D_max of the spinal cord (p = 0.02), there may be a risk of slight underestimation compared with EDC. A weak correlation for D₉₅ in the PTV and D_{0.5 cc} in the duodenum was observed.

CONCLUSION

For patients with similar inter-fractional intestinal gas distribution, EDC had little dosimetric effects on the D_{0.5 cc} of all GI organs and dose volume parameters of target in most plans.

ADVANCES IN KNOWLEDGE

By omitting the EDC of intestinal gas, the online SMART treatment time can be shortened.

Intensified systemic therapy and stereotactic ablative radiotherapy dose for patients with unresectable pancreatic adenocarcinoma

PURPOSE

We aimed to report the long-term impact of modern chemotherapy and SABR dose regimens on oncologic outcomes of unresectable pancreatic adenocarcinoma (PA).

MATERIALS AND METHODS

We reviewed the treatment characteristics and outcomes of all patients who received multi-fraction SABR for unresectable PA between February 2007 and August 2018 at our institution. Time-to-events were calculated from date of diagnosis treating death as a competing risk.

RESULTS

A total of 149 patients were identified. Median follow-up was 15 months (range: 5-47). Median SABR dose was 33 Gy (range: 20-45) delivered in 5 fractions in 143 patients, and 3 or 6 fractions in 6 patients. 107 patients (72%) received gemcitabine-based chemotherapy while 31 (21%) received modified FOLFIRINOX (mFFX). Median OS was 16 months (95% CI, 14-17), with a 1-year cumulative incidence of LF of 14%. The combination of SABR doses ≥40 Gy and mFFX (n = 21) showed a superior PFS and OS to the use of GEM-based chemotherapy with <40 Gy SABR doses (median PFS: 14 vs. 10 months, HR: 0.46, 95% CI: 0.29-0.71, P = 0.003; median OS: 24 vs. 14 months, HR: 0.36, 95% CI: 0.22-0.59, P = 0.002), with 1-year PFS and OS of 67% and 90% compared to 35% and 59% for those who received GEM-based chemotherapy with <40 Gy SABR doses, respectively.

CONCLUSIONS

The use of mFFX and a SABR dose ≥40 Gy in 5 fractions may be superior compared to regimens that utilize gemcitabine-based chemotherapy or SABR doses <40 Gy.

Novel strategies using modern radiotherapy to improve pancreatic cancer outcomes: toward a new standard?

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most aggressive solid tumours with an estimated 5-year overall survival rate of 7% for all stages combined. In this highly resistant disease that is located in the vicinity of many radiosensitive organs, the role of radiotherapy (RT) and indications for its use in this setting have been debated for a long time and are still under investigation. Although a survival benefit has yet to be clearly demonstrated for RT, it is the only technique, other than surgery, that has been demonstrated to lead to local control improvement. The adjuvant approach is now strongly challenged by neoadjuvant treatments that could spare patients with rapidly progressive systemic disease from unnecessary surgery and may increase free margin (R0) resection rates for those eligible for surgery. Recently developed dose-escalated RT treatments, designed either to maintain full-dose chemotherapy or to deliver a high biologically effective dose, particularly to areas of contact between the tumour and blood vessels, such as hypofractionated ablative RT (HFA-RT) or stereotactic body RT (SBRT), are progressively changing the treatment landscape. These modern strategies are currently being tested in prospective clinical trials with encouraging preliminary results, paving the way for more effective treatment combinations using novel targeted therapies. This review summarizes the current literature regarding the use of RT for the treatment of primary PDAC, describes the limitations of conventional RT, and discusses the emerging role of dose-escalated RT and heavy-particle RT.

The Utility of Stereotactic Ablative Radiation Therapy for Palliation of Metastatic Pancreatic Adenocarcinoma

PURPOSE

Our purpose was to report the outcome of stereotactic ablative radiation therapy (SABR) to the primary tumor for patients with metastatic pancreatic cancer.

METHODS AND MATERIALS

We examined the records of patients with metastatic pancreatic cancer treated with SABR to the primary tumor between 2002 and 2018. Toxicities were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events Version 4.03. Pain intensity pre- and post-SABR was scored according to the Stanford Pain Scale as reported by the patient. Time-to-events were calculated from the date of end of SABR delivery.

RESULTS

In total, 27 patients were identified that met the inclusion criteria. Seventeen (63%) patients received single fraction SABR with a median dose of 25 Gy (range, 12.5-25), and 10 (37%) patients were treated in 5 fractions with a median dose of 33 Gy (range, 25-40). Before the start of SABR, 17 (63%) patients reported having abdominal pain, with a median intensity of 5 in the 0 to 10 pain scale (range, 1-9), 11 (41%) of them needing continuous opioid use. The median follow-up was 6 months (range, 0-18). Median overall survival was 7 months (95% confidence interval, 3-10), with a cumulative incidence of local failures at 1 year of 25% (95% confidence interval, 10-44). After SABR, there was a significant reduction in the mean intensity of pain (P = .01), and a 46% relative reduction in continuous opioid use. Only 2 patients (7%) presented a grade 3 toxicity that could be attributed to treatment.

CONCLUSIONS

In this small series, SABR was a safe and effective option for the local palliation of metastatic pancreatic cancer, with measurable improvements in abdominal pain and the need for opioids.

Differential regulation of microRNA-15a by radiation affects angiogenesis and tumor growth via modulation of acid sphingomyelinase

Activation of acid sphingomyelinase (SMPD1) and the generation of ceramide is a critical regulator of apoptosis in response to cellular stress including radiation. Endothelial SMPD1 has been shown to regulate tumor responses to radiation therapy. We show here that the SMPD1 gene is regulated by a microRNA (miR), miR-15a, in endothelial cells (ECs). Standard low dose radiation (2 Gy) upregulates miR-15a and decreases SMPD1 levels. In contrast, high dose radiation (10 Gy and above) decreases miR-15a and increases SMPD1. Ectopic expression of miR-15a decreases both mRNA and protein levels of SMPD1. Mimicking the effects of high dose radiation with a miR-15a inhibitor decreases cell proliferation and increases active Caspase-3 & 7. Mechanistically, inhibition of miR-15a increases inflammatory cytokines, activates caspase-1 inflammasome and increases Gasdermin D, an effector of pyroptosis. Importantly, both systemic and vascular-targeted delivery of miR-15a inhibitor decreases angiogenesis and tumor growth in a CT26 murine colorectal carcinoma model. Taken together, our findings highlight a novel role for miR mediated regulation of SMPD1 during radiation responses and establish proof-of-concept that this pathway can be targeted with a miR inhibitor.

Lymphocyte-sparing effect of stereotactic body radiation therapy compared to conventional fractionated radiation therapy in patients with locally advanced pancreatic cancer

BACKGROUND

Conventionally fractionated (CF) radiation therapy (RT) has been associated with lymphopenia, leading to compromised overall survival (OS) in cancer patients. It currently remains unknown if stereotactic body (SB) RT induces lymphopenia to the same degree. The aim of this study is to determine if SBRT with either chemotherapy (CMT) (Fluorouracil (5FU) or capecitabine) or Nelfinavir (NFV) to pancreatic adenocarcinoma induces lymphopenia to the same degree as CFRT with 5FU or capecitabine and how any associated difference affects patient survival outcomes.

METHODS

Medical records of pancreatic adenocarcinoma patients treated with induction CMT followed by RT with concurrent CMT or NFV were reviewed. Patients with total lymphocyte counts (TLCs) available both prior to and following initiation of RT were included. Three groups were identified: CFRT/CMT, SBRT/CMT, and SBRT/NFV. Median delivered RT doses for CFRT and SBRT were 50.4 Gy in 1.8 Gy fractions and 35 Gy in 7 Gy fractions, respectively. TLCs from day 0 (the first day of RT) to 40 were recorded and analyzed using the Kruskal-Wallis test with p-values adjusted with Bonferroni's method. Linear regressions were utilized to estimate the slope of TLCs as it changes with time and survival analysis was performed via Kaplan-Meier plots.

RESULTS

One hundred patients were identified (28 CFRT/CMT, 27 SBRT/CMT, 45 SBRT/NFV). Median pre-RT TLCs were not different among groups. Median lowest TLCs were significantly lower (p <  0.0001) and median TLCs reduction over time were significantly greater (p <  0.0001) in the CFRT group than SBRT groups. There was no difference in lowest TLCs or TLCs reduction over time between SBRT groups. Across all groups, the median time to lowest TLCs was similar. Survival analysis revealed no significant difference in median OS between SBRT and CFRT groups. However, in patients with surgery, Median OS for patients with SBRT/CMT was significantly higher than in those with SBRT/NFV (p = 0.03).

CONCLUSIONS

Compared to CFRT, SBRT is associated with less lymphopenia. Further study of the effect of radiation technique on immune status is warranted.

Evaluation of the effects of motion mitigation strategies on respiration-induced motion in each pancreatic region using cine-magnetic resonance imaging

Purpose

This study aimed to quantify the respiration‐induced motion in each pancreatic region during motion mitigation strategies and to characterize the correlations between this motion and that of the surrogate signals in cine‐magnetic resonance imaging (MRI). We also aimed to evaluate the effects of these motion mitigation strategies in each pancreatic region.

Methods

Sagittal and coronal two‐dimensional cine‐MR images were obtained in 11 healthy volunteers, eight of whom also underwent imaging with abdominal compression (AC). For each pancreatic region, the magnitude of pancreatic motion with and without motion mitigation and the positional error between the actual and predicted pancreas motion based on surrogate signals were evaluated.

Results

The magnitude of pancreatic motion with and without AC in the left–right (LR) and superior–inferior (SI) directions varied depending on the pancreatic region. In respiratory gating (RG) assessments based on a surrogate signal, although the correlation was reasonable, the positional error was large in the pancreatic tail region. Furthermore, motion mitigation in the anterior‐posterior and SI directions with RG was more effective than was that with AC in the head region.

Conclusions

This study revealed pancreatic region‐dependent variations in respiration‐induced motion and their effects on motion mitigation outcomes during AC or RG. The magnitude of pancreatic motion with or without AC and the magnitude of the positional error with RG varied depending on the pancreatic region. Therefore, during radiation therapy for pancreatic cancer, it is important to consider that the effects of motion mitigation during AC or RG may differ depending on the pancreatic region.

FLT-PET-CT for the Detection of Disease Recurrence After Stereotactic Ablative Radiotherapy or Hyperfractionation for Thoracic Malignancy: A Prospective Pilot Study

Differentiating local recurrence from post-treatment changes on PET scans following stereotactic ablative radiotherapy (SABR) or hyperfractionation for lung tumors is challenging. We performed a prospective pilot study of 3-deoxy-3-[¹⁸F]-fluorothymidine (FLT)-PET-CT in patients with equivocal post-radiation FDG-PET-CT to assess disease recurrence.

Methods: We prospectively enrolled 10 patients, 9 treated with SABR and 1 with hyperfractionated external beam radiotherapy for thoracic malignancy with subsequent equivocal follow-up FDG-PET-CT, to undergo FLT-PET-CT prior to biopsy or serial imaging. FLT-PET scans were interpreted by a radiologist with experience in reading FLT-PET-CT and blinded to the results of any subsequent biopsy or imaging.

Results: Of the 10 patients enrolled, 8 were evaluable after FLT-PET-CT. Based on the FLT-PET-CT, a blinded radiologist accurately predicted disease recurrence vs. inflammatory changes in 7 patients (87.5%). The combination of higher lesion SUV_max and higher ratio of lesion SUV_max to SUV_max of mediastinal blood pool was indicative of recurrence. Qualitative assessment of increased degree of focality of the lesion also appears to be indicative of disease recurrence.

Conclusion: Adjunctive FLT-PET-CT imaging can complement FDG-PET-CT scan in distinguishing post-treatment radiation changes from disease recurrence in thoracic malignancies. These findings support the investigation of FLT-PET-CT in a larger prospective study.

Technical Assessment of an Automated Treatment Planning on Dose Escalation of Pancreas Stereotactic Body Radiotherapy

BACKGROUND

Stereotactic body radiotherapy has been suggested to provide high rates of local control for locally advanced pancreatic cancer. However, the close proximity of highly radiosensitive normal tissues usually causes the labor-intensive planning process and may impede further escalation of the prescription dose.

PURPOSE

The present study aims to evaluate the consistency and efficiency of Pinnacle Auto-Planning for pancreas stereotactic body radiotherapy with original prescription and escalated prescription.

METHODS

Twenty-four patients with pancreatic cancer treated with stereotactic body radiotherapy were studied retrospectively. The prescription is 40 Gy over 5 consecutive fractions. Most of patients (n = 21) also had 3 other different dose-level targets (6 Gy/fraction, 5 Gy/fraction, and 4 Gy/fraction). Two types of plans were generated by Pinnacle Auto-Planning with the original prescription (8 Gy/fraction, 6 Gy/fraction, 5 Gy/fraction, and 4 Gy/fraction) and escalated prescription (9 Gy/fraction, 7 Gy/fraction, 6 Gy/fraction, and 5 Gy/fraction), respectively. The same Auto-Planning template, including beam geometry, intensity-modulated radiotherapy objectives and intensity-modulated radiotherapy optimization parameters, were utilized for all the auto-plans in each prescription group. The intensity-modulated radiotherapy objectives do not include any manually created structures. Dosimetric parameters including percentage volume of PTV receiving 100% of the prescription dose, percentage volume of PTV receiving 93% of the prescription dose, and consistency of the dose-volume histograms of the target volumes were assessed. Dmax and D1 cc of highly radiosensitive organs were also evaluated.

RESULTS

For all the pancreas stereotactic body radiotherapy plans with the original or escalated prescriptions, auto-plans met institutional dose constraints for critical organs, such as the duodenum, small intestine, and stomach. Furthermore, auto-plans resulted in acceptable planning target volume coverage for all targets with different prescription levels. All the plans were generated in a one-attempt manner, and very little human intervention is necessary to achieve such plan quality.

CONCLUSIONS

Pinnacle3 Auto-Planning consistently and efficiently generate acceptable treatment plans for multitarget pancreas stereotactic body radiotherapy with or without dose escalation and may play a more important role in treatment planning in the future.

Pancreatic cancer: a symptomless killer

Pancreatic cancer is the fifth most common cause of cancer death in the UK. This disease often remains undiagnosed until it is at a late stage, resulting in the majority of tumours being unsuitable for surgical resection. When a diagnosis of pancreatic cancer is confirmed, early input from the multi-disciplinary team (MDT) is vital. Due to the poor prognosis, the screening and treatment of pancreatic cancer remains a considerable challenge for medicine in the 21st century.

One- vs. Three-Fraction Pancreatic Stereotactic Body Radiation Therapy for Pancreatic Carcinoma: Single Institution Retrospective Review

Background/introduction

Early reports of stereotactic body radiation therapy (SBRT) for pancreatic ductal adenocarcinoma (PDAC) used single fraction, but eventually shifted to multifraction regimens. We conducted a single institution review of our patients treated with single- or multifraction SBRT to determine whether any outcome differences existed.

Methods and materials

Patients treated with SBRT in any setting for PDAC at our facility were included, from 2004 to 2014. Overall survival (OS), local control (LC), regional control (RC), distant metastasis (DM), and late grade 3 or greater radiation toxicities from the time of SBRT were calculated using Kaplan–Meier estimation to either the date of last follow-up/death or local/regional/distant failure.

Results

We identified 289 patients (291 lesions) with pathologically confirmed PDAC. Median age was 69 (range, 33–90) years. Median gross tumor volume was 12.3 (8.6–21.3) cm³ and planning target volume 17.9 (12–27) cm³. Single fraction was used in 90 (30.9%) and multifraction in 201 (69.1%) lesions. At a median follow-up of 17.3 months (IQR 10.1–29.3 months), the median survival for the entire cohort 17.8 months with a 2-year OS of 35.3%. Univariate analysis showed multifraction schemes to have a higher 2-year OS 30.5% vs. 37.5% (p = 0.019), it did not hold significance on MVA. Multifractionation schemes were found to have a higher LC on MVA (HR = 0.53, 95% CI, 0.33–0.85, p = 0.009). At 2 years, late grade 3+ toxicity was 2.5%. Post-SBRT CA19-9 was found on MVA to be a prognostic factor for OS (HR = 1.01, 95% CI, 1.01–1.01, p = 0.009), RC (HR = 1.01, 95% CI 1.01–1.01, p = 0.02), and DM (HR = 1.01, 95% CI, 1.01–1.01, p = 0.001).

Conclusion

Our single institution retrospective review is the largest to date comparing single and multifraction SBRT and the first to show multifraction regimen SBRT to have a higher LC than single fractionation. Additionally, we show low rates of severe late toxicity with SBRT.

Potential dosimetric benefits of adaptive tumor tracking over the internal target volume concept for stereotactic body radiation therapy of pancreatic cancer

BACKGROUND

Radiotherapy for pancreatic cancer has two major challenges: (I) the tumor is adjacent to several critical organs and, (II) the mobility of both, the tumor and its surrounding organs at risk (OARs). A treatment planning study simulating stereotactic body radiation therapy (SBRT) for pancreatic tumors with both the internal target volume (ITV) concept and the tumor tracking approach was performed. The two respiratory motion-management techniques were compared in terms of doses to the target volume and organs at risk.

METHODS AND MATERIALS

Two volumetric-modulated arc therapy (VMAT) treatment plans (5 × 5 Gy) were created for each of the 12 previously treated pancreatic cancer patients, one using the ITV concept and one the tumor tracking approach. To better evaluate the overall dose delivered to the moving tumor volume, 4D dose calculations were performed on four-dimensional computed tomography (4DCT) scans. The resulting planning target volume (PTV) size for each technique was analyzed. Target and OAR dose parameters were reported and analyzed for both 3D and 4D dose calculation.

RESULTS

Tumor motion ranged from 1.3 to 11.2 mm. Tracking led to a reduction of PTV size (max. 39.2%) accompanied with significant better tumor coverage (p<0.05, paired Wilcoxon signed rank test) both in 3D and 4D dose calculations and improved organ at risk sparing. Especially for duodenum, stomach and liver, the mean dose was significantly reduced (p<0.05) with tracking for 3D and 4D dose calculations.

CONCLUSIONS

By using an adaptive tumor tracking approach for respiratory-induced pancreatic motion management, a significant reduction in PTV size can be achieved, which subsequently facilitates treatment planning, and improves organ dose sparing. The dosimetric benefit of tumor tracking is organ and patient-specific.

Primary systemic therapy in resectable pancreatic ductal adenocarcinoma using mFOLFIRINOX: A pilot study

BACKGROUND AND OBJECTIVES

Surgery followed by gemcitabine and/or a fluoropyrimidine is standard therapy for resectable PDAC. mFOLFIRINOX (oxaliplatin 85 mg/m² , irinotecan 180 mg/m² , leucovorin 400 mg/m² Day 1, 5-FU 2400 mg/m²  × 48 h IV, peg-filgrastim 6 mg SQ day 3, every 14 days) has substantial activity in metastatic PDAC. We wished to determine the tolerability/efficacy of peri-operative mFOLFIRINOX in resectable PDAC.

METHODS

Patients with resectable PDAC (ECOG PS 0/1) received four cycles of mFOLFIRINOX pre- and post-surgery. The primary endpoint was completion of preoperative chemotherapy plus resection. Secondary endpoints included completion of all therapy, R0 resection, treatment related toxicity, PFS, and OS.

RESULTS

Twenty-one patients enrolled: median age 62 (47-78); 20/21 (95%) completed four cycles of preoperative mFOLFIRINOX; response by RECIST was 1 CR, 3 PR, 16 SD; 17/21 (81%) completed resection, 16/21 (76%) R0; 14/21 (66%) completed four cycles of postoperative mFOLFIRINOX. Grade 3 and 4 toxicity occurred in 23% and 14% patients pre-operatively, 26% and 6.0% post-operatively. Nine patients are alive with median follow-up of 27.7 (3.1-47.1) months.

CONCLUSIONS

PST using mFOLFIRINOX in resectable PDAC is feasible and tolerable. R0 resection rate is high and survival promising, requiring longer follow-up and larger studies for definitive assessment.

Improved vessel-tissue contrast and image quality in 3D radial sampling-based 4D-MRI

Purpose

In radiation treatment planning for thoracic and abdominal tumors, 4D‐MRI has shown promise in respiratory motion characterization with improved soft‐tissue contrast compared to clinical standard, 4D computed tomography (4D‐CT). This study aimed to further improve vessel–tissue contrast and overall image quality in 3D radial sampling‐based 4D‐MRI using a slab‐selective (SS) excitation approach.

Methods

The technique was implemented in a 3D radial sampling with self‐gating‐based k‐space sorting sequence. The SS excitation approach was compared to a non‐selective (NS) approach in six cancer patients and two healthy volunteers at 3T. Improvements in vessel–tissue contrast ratio (CR) and vessel signal‐to‐noise ratio (SNR) were analyzed in five of the eight subjects. Image quality was visually assessed in all subjects on a 4‐point scale (0: poor; 3: excellent). Tumor (patients) and pancreas (healthy) motion trajectories were compared between the two imaging approaches.

Results

Compared with NS‐4D‐MRI, SS‐4D‐MRI significantly improved the overall vessel–tissue CR (2.60 ± 3.97 vs. 1.03 ± 1.44, P < 0.05), SNR (63.33 ± 38.45 vs. 35.74 ± 28.59, P < 0.05), and image quality score (2.6 ± 0.5 vs. 1.4 ± 0.5, P = 0.02). Motion trajectories from the two approaches exhibited strong correlation in the superior–inferior (0.96 ± 0.06), but weaker in the anterior–posterior (0.78 ± 0.24) and medial–lateral directions (0.46 ± 0.44).

Conclusions

The proposed 4D‐MRI with slab‐selectively excited 3D radial sampling allows for improved blood SNR, vessel–tissue CR, and image quality.

Optimizing tumor immune response through combination of radiation and immunotherapy

Radiation therapy and immunotherapy are two highly evolving modalities for the treatment of solid tumors. Immunotherapeutic drugs can either stimulate the immune system via immunogenic pathways or target co-inhibitory checkpoints. An augmented tumor cell recognition by host immune cells can be achieved post-irradiation, as irradiated tissues can release chemical signals which are sensed by the immune system resulting in its activation. Different strategies combining both treatment modalities were tested in order to achieve a better therapeutic response and longer tumor control. Both regimens act synergistically to one another with complimentary mechanisms. In this review, we explore the scientific basis behind such a combination, starting initially with a brief historical overview behind utilizing radiation and immunotherapies for solid tumors, followed by the different types of these two modalities, and the biological concept behind their synergistic effect. We also shed light on the common side effects and toxicities associated with radiation and immunotherapy. Finally, we discuss previous clinical trials tackling this multimodality combination and highlight future ongoing research.

Fast and robust online adaptive planning in stereotactic MR-guided adaptive radiation therapy (SMART) for pancreatic cancer

BACKGROUND AND PURPOSE

To implement a robust and fast stereotactic MR-guided adaptive radiation therapy (SMART) online strategy in locally advanced pancreatic cancer (LAPC).

MATERIAL AND METHODS

SMART strategy for plan adaptation was implemented with the MRIdian system (ViewRay Inc.). At each fraction, OAR (re-)contouring is done within a distance of 3cm from the PTV surface. Online plan re-optimization is based on robust prediction of OAR dose and optimization objectives, obtained by building an artificial neural network (ANN). Proposed limited re-contouring strategy for plan adaptation (SMART_3CM) is evaluated by comparing 50 previously delivered fractions against a standard (re-)planning method using full-scale OAR (re-)contouring (FULLOAR). Plan quality was assessed using PTV coverage (V_95%, D_mean, D_1cc) and institutional OAR constraints (e.g. V_33Gy).

RESULTS

SMART_3CM required a significant lower number of optimizations than FULLOAR (4 vs 18 on average) to generate a plan meeting all objectives and institutional OAR constraints. PTV coverage with both strategies was identical (mean V_95%=89%). Adaptive plans with SMART_3CM exhibited significant lower intermediate and high doses to all OARs than FULLOAR, which also failed in 36% of the cases to adhere to the V_33Gy dose constraint.

CONCLUSIONS

SMART_3CM approach for LAPC allows good OAR sparing and adequate target coverage while requiring only limited online (re-)contouring from clinicians.

The Role of Consolidation Chemoradiotherapy in Locally Advanced Pancreatic Cancer Receiving Chemotherapy: An Updated Systematic Review and Meta-Analysis

Purpose

The role of consolidation chemoradiation (CCRT) after systemic chemotherapy in locally advanced pancreatic cancer (LAPC) is still controversial. We aim to evaluate the effectiveness of CCRT in LAPC using systematic review and meta-analysis of prospective studies.

Materials and Methods

Prospective clinical trials of LAPC receiving chemotherapy with or without subsequent CCRT were included in the analysis. We systematically searched in PubMed, MEDLINE, Embase, and Web of Science. The primary outcome of interest was 1-year survival. Secondary endpoints were median overall survival, progression-free survival, toxicity, and resection rate.

Results

Forty-one studies with 49 study arms were included with a total of 1,018 patients receiving CCRT after induction chemotherapy (ICT) and 954 patients receiving chemotherapy alone. CCRT after ICT did not improve 1-year survival significantly in LAPC patients compared with chemotherapy alone (58% vs. 52%). ICT lasted for at least 3 months revealed significantly improved survival of additional CCRT to LAPC patients compared to chemotherapy alone (65% vs. 52%). A marginal survival benefit of consolidation CCRT was noted in studies using maintenance chemotherapy (59% vs. 52%), and fluorouracil-based CCRT (64% vs. 52%), as well as in studies conducted after the 2010 (64% vs. 55%).

Conclusion

The survival benefit of ICT+CCRT over chemotherapy alone in treating LAPC was noted when ICT lasted for at least 3 months. Fluorouracil-based CCRT, and maintenance chemotherapy were associated with improved clinical outcomes.

An evaluation of motion mitigation techniques for pancreatic SBRT

BACKGROUND AND PURPOSE

Ablative radiation therapy can be beneficial for pancreatic cancer, and motion mitigation helps to reduce dose to nearby organs-at-risk. Here, we compared two competing methods of motion mitigation-abdominal compression and respiratory gating.

MATERIALS AND METHODS

CBCT scans of 19 pancreatic cancer patients receiving stereotactic body radiation therapy were acquired with and without abdominal compression, and 3D target motion was reconstructed from CBCT projection images. Daily target motion without mitigation was compared against motion with compression and with simulated respiratory gating. Gating was free-breathing and based on an external surrogate. Target coverage was also evaluated for each scenario by simulating reduced target margins.

RESULTS

Without mitigation, average daily target motion in LR/AP/SI directions was 5.3, 7.3, and 13.9mm, respectively. With abdominal compression, these values were 5.2, 5.3, and 8.5mm, and with respiratory gating they were 3.2, 3.9, and 5.5mm, respectively. Reductions with compression were significant in AP/SI directions, while reductions with gating were significant in all directions. Respiratory gating also demonstrated better coverage in the reduced margins scenario.

CONCLUSION

Respiratory gating is the most effective strategy for reducing motion in pancreatic SBRT, and may allow for dose escalation through a reduction in target margin.

Stereotactic body radiotherapy (SBRT) in recurrent or oligometastatic pancreatic cancer : A toxicity review of simultaneous integrated protection (SIP) versus conventional SBRT

BACKGROUND

Stereotactic body radiotherapy (SBRT) in pancreatic cancer can be limited by its proximity to organs at risk (OAR). In this analysis, we evaluated the toxicity and efficacy of two different treatment approaches in patients with locally recurrent or oligometastatic pancreatic cancer.

MATERIALS AND METHODS

According to the prescription method, patients were divided in two cohorts (C1 and C2). The planning target volume (PTV) was created through a 4 mm expansion of the internal target volume. In C2, a subvolume was additionally created, a simultaneous integrated protection (SIP), which is the overlap of the PTV with the planning risk volume of an OAR to which we prescribed a reduced dose.

RESULTS

In all, 18 patients were treated (7 with local recurrences, 9 for oligometastases, 2 for both). Twelve of 23 lesions were treated without SIP (C1) and 11 with SIP (C2). The median follow-up was 12.8 months. Median overall survival (OS) was 13.2 (95% confidence interval [CI] 9.8-14.6) months. The OS rates at 6 and 12 months were 87 and 58%, respectively. Freedom from local progression for combined cohorts at 6 and 12 months was 93 and 67% (95% CI 15-36), respectively. Local control was not statistically different between the two groups. One patient in C2 experienced grade ≥3 acute toxicities and 1 patient in C1 experienced a grade ≥3 late toxicity.

CONCLUSION

The SIP approach is a useful prescription method for abdominal SBRT with a favorable toxicity profile which does not compromise local control and overall survival despite dose sacrifices in small subvolumes.

Reirradiation with stereotactic body radiation therapy after prior conventional fractionation radiation for locally recurrent pancreatic adenocarcinoma

Purpose

Locally recurrent pancreatic cancer after prior radiotherapy is a therapeutic challenge with limited treatment options. This study examines the safety and efficacy of stereotactic body radiation therapy (SBRT) for locally recurrent pancreatic adenocarcinoma after prior conventional fractionation radiotherapy (CRT).

Methods and materials

Outcomes from all patients treated with SBRT for locally recurrent pancreatic adenocarcinoma after prior CRT at our institution were reviewed. A total of 23 patients were identified. Prior CRT median dose was 50.4 Gy (range, 30-60 Gy). Twelve patients (52%) had previously undergone surgery and received CRT as neo- or adjuvant treatment. Nine patients (39.1%) were reirradiated with SBRT with a dose of 25 Gy in a single fraction, and 14 patients (60.8%) received a 5-fraction SBRT schedule with a median dose of 25 Gy (range, 20-33 Gy) in 5 fractions (1-5 fractions).

Results

Median follow-up time was 28 months (range, 9-77 months). The median planning target volume was 46 cm³ (range, 14-89 cm³). Median overall survival from diagnosis and from reirradiation were 27.5 months (range, 10-77 months) and 8.5 months (range, 1 month to not reached) respectively. The cumulative incidence of local failures at the last follow-up was 19%. For the 4 patients who presented with local failure, one was treated with a single fraction of 25 Gy, and the other 3 were treated with 25 Gy in 5 fractions. Three patients presented regional failure, with a cumulative incidence of 14%, all with concurrent distant progression. The cumulative incidence of distant progression was 64% at last follow-up. After reirradiation, 6 patients (26.1%) developed a grade 2 or 3 gastrointestinal toxicity, 4 of them occurring among patients treated with a single-fraction SBRT regimen.

Conclusions

Our report shows that SBRT for reirradiation of locally recurrent pancreas adenocarcinoma is a feasible option with good local control and acceptable toxicity rates, especially with a multifraction schedule.

Endoscopic ultrasound in pancreatic cancer: innovative applications beyond the basics

Endoscopic ultrasound (EUS) has become a mainstay in assisting in the diagnosis and staging of pancreatic cancer. In addition, EUS provides a modality to treat chronic pain through celiac plexus neurolysis. Currently, there is growing data and utilization of EUS in more diverse and innovative applications aimed at providing more sophisticated diagnostic, prognostic and therapeutic options for patients with pancreatic cancer. EUS delivery of chemotherapy, viral and biological vectors and fiducial markers may eventually revolutionize the way clinicians approach the care of a patient with pancreatic cancer.

Stereotactic body radiotherapy for the pancreas: a critical review for the medical oncologist

With recent advances in imaging modalities and radiation therapy, stereotactic body radiotherapy (SBRT) has allowed for the delivery of high doses of radiation with accuracy and precision. As such, SBRT has generated favorable results in the treatment of several cancers. Although the role of radiation has been controversial for the treatment of pancreatic ductal adenocarcinoma (PDAC) due to rather lackluster results in clinical trials, SBRT may offer improved outcomes, enhance the quality of life, and aid in palliative care settings for PDAC patients. This review delineates the role of SBRT in the treatment of PDAC, presents the defining principles of radiation biology and the radiation oncology work flow, and discusses the prospects of new treatment regimens involving tumor immunology and radiation therapy.

Neoadjuvant Therapy for Pancreatic Cancer: Systematic Review of Postoperative Morbidity, Mortality, and Complications

The purpose of this review was to assess whether neoadjuvant chemotherapy and chemoradiotherapy (CRT) result in differential postoperative morbidity and mortality as compared with pancreatic tumor resection surgery alone. Using PRISMA guidelines and the PubMed search engine, we reviewed all prospective phase II trials of neoadjuvant chemotherapy and CRT for pancreatic cancer that examined postoperative morbidities and mortalities. A total of 30 articles were identified, collated, and analyzed. Risks of postoperative complications vary based on trial. With surgery alone, the most common postoperative complications included delayed gastric emptying (DGE) (17% to 24%), pancreatic fistula (10% to 20%), anastomotic leaks (0% to 15%), postoperative bleeding (2% to 13%), and infections/sepsis (17% to 20%). With surgery alone, the mortality was <5%. Neoadjuvant chemotherapy showed comparable fistula rates (3% to 4%), leaks (3% to 11%), infection (3% to 7%), with mortality 0% to 4% in all but 1 study. CRT for resectable/borderline resectable patients also showed comparable complication rates: DGE (6% to 15%), fistulas (2% to 3%), leaks (3% to 7%), bleeding/hemorrhage (2% to 13%), infections/sepsis (3% to 19%), with 9/13 studies showing a mortality of ≤4%. As compared with initially borderline/resectable tumors, CRT for initially unresectable tumors (despite less data) showed higher complication rates: DGE (13% to 33%), fistulas (3% to 25%), infections/sepsis (3% to 16%). However, the confounding factor of the potentially higher tumor burden as an associative agent remains. The only parameters slightly higher than historical surgery-only complication rates were leaks and bleeding/hemorrhage (13% to 20%). Mortality rates in these patients were consistently 0%, with 2 outliers. Hence, neoadjuvant chemotherapy/CRT is safe from a postoperative complication standpoint, without significant increases in complication rates compared with surgery alone. Resectable and borderline resectable patients have fewer complications as compared with unresectable patients, although data for the latter are lacking.

Neoadjuvant radiotherapeutic strategies in pancreatic cancer

This review summarizes the current status of neoadjuvant radiation approaches in the treatment of pancreatic cancer, including a description of modern radiation techniques, and an overview on the literature regarding neoadjuvant radio- or radiochemotherapeutic strategies both for resectable and irresectable pancreatic cancer. Neoadjuvant chemoradiation for locally-advanced, primarily non- or borderline resectable pancreas cancer results in secondary resectability in a substantial proportion of patients with consecutively markedly improved overall prognosis and should be considered as possible alternative in pretreatment multidisciplinary evaluations. In resectable pancreatic cancer, outstanding results in terms of response, local control and overall survival have been observed with neoadjuvant radio- or radiochemotherapy in several phase I/II trials, which justify further evaluation of this strategy. Further investigation of neoadjuvant chemoradiation strategies should be performed preferentially in randomized trials in order to improve comparability of the current results with other treatment modalities. This should include the evaluation of optimal sequencing with newer and more potent systemic induction therapy approaches. Advances in patient selection based on new molecular markers might be of crucial interest in this context. Finally modern external beam radiation techniques (intensity-modulated radiation therapy, image-guided radiation therapy and stereotactic body radiation therapy), new radiation qualities (protons, heavy ions) or combinations with alternative boosting techniques widen the therapeutic window and contribute to the reduction of toxicity.

Current therapeutic strategies for advanced pancreatic cancer: A review for clinicians

Pancreatic cancer (PC) would become the second leading cause of cancer death in the near future, despite representing only 3% of new cancer diagnosis. Survival improvement will come from a better knowledge of risk factors, earlier diagnosis, better integration of locoregional and systemic therapies, as well as the development of more efficacious drugs rising from a deeper understanding of disease biology. For patients with unresectable, non-metastatic disease, combined strategies encompassing primary chemotherapy and radiation seems to be promising. In fit patients, new polychemotherapy regimens can lead to better outcomes in terms of slight but significant survival improvement associated with a positive impact on quality of life. The upfront use of these regimes can also increase the rate of radical resections in borderline resectable and locally advanced PC. Second line treatments showed to positively affect both overall survival and quality of life in fit patients affected by metastatic disease. At present, oxaliplatin-based regimens are the most extensively studied. Nonetheless, other promising drugs are currently under evaluation. Presently, in addition to surgery and conventional radiation therapy, new locoregional treatment techniques are emerging as alternative options in the multimodal approach to patients or diseases not suitable for radical surgery. As of today, in contrast with other types of cancer, targeted therapies failed to show relevant activity either alone or in combination with chemotherapy and, thus, current clinical practice does not include them. Up to now, despite the fact of extremely promising results in different tumors, also immunotherapy is not in the actual therapeutic armamentarium for PC. In the present paper, we provide a comprehensive review of the current state of the art of clinical practice and research in PC aiming to offer a guide for clinicians on the most relevant topics in the management of this disease.

Adjuvant therapy for pancreas cancer in an era of value based cancer care

In resected pancreas cancer, adjuvant therapy improves outcomes and is considered the standard of care for patients who recover sufficiently post operatively. Chemotherapy or combined chemotherapy and radiation therapy (chemoradiation; CRT) are strategies used in the adjuvant setting. However, there is a lack of evidence to suggest whether the addition of RT to chemotherapy translates to an improvement in clinical outcomes. This is true even when accounting for the subset of patients with a higher risk for recurrence, such as those with R1 and lymph node positive disease. When considering the direct and indirect costs, impact on quality of life and questionable added clinical benefit, the true "net health benefit" from added RT to chemotherapy becomes more uncertain. Future directions, including the utilization of modern RT, integration of novel therapies, and intensifying chemotherapy regimens may improve outcomes in resected pancreas cancer.

Neoadjuvant multimodal treatment of pancreatic ductal adenocarcinoma

Treatment of pancreatic ductal adenocarcinoma (PDAC) is increasingly multidisciplinary, with neoadjuvant strategies (chemotherapy, radiation, and surgery) administered in patients with resectable, borderline resectable, or locally advanced disease. The rational supporting this management is the achievement of both higher margin-negative resections and conversion rates into potentially resectable disease and in vivo assessment of novel therapeutics. International guidelines suggest an initial staging of the disease followed by a multidisciplinary approach, even considering the lack of a treatment approach to be considered as standard in this setting. This review will focus on both literature data supporting these guidelines and on new opportunities related to current more active chemotherapy regimens. An analysis of the pathological assessment of response to therapy and the potential role of target therapies and translational biomarkers and ongoing clinical trials of significance will be discussed.

Clinical implementation of stereotactic body radiation therapy in pancreatic cancer and hepatocellular carcinoma

With the development of radiation technology, more emphasis has been placed on the application of stereotactic body radiation therapy (SBRT) for the treatment of pancreatic cancer and hepatocellular carcinoma. The use of SBRT contributes to the advantage of dose distributions, resulting in maximum doses in target volumes and minimum doses in surrounding normal tissues. Due to a variety of treatment modalities, different clinical results have been presented in different plans. This article gives a summary of SBRT in the treatment of pancreatic cancer and hepatocellular carcinoma.

Caveolin-1 is Associated with Tumor Progression and Confers a Multi-Modality Resistance Phenotype in Pancreatic Cancer

Caveolin-1 (Cav-1) is a 21 kDa protein enriched in caveolae, and has been implicated in oncogenic cell transformation, tumorigenesis, and metastasis. We explored roles for Cav-1 in pancreatic cancer (PC) prognostication, tumor progression, resistance to therapy, and whether targeted downregulation could lead to therapeutic sensitization. Cav-1 expression was assessed in cell lines, mouse models, and patient samples, and knocked down in order to compare changes in proliferation, invasion, migration, response to chemotherapy and radiation, and tumor growth. We found Cav-1 is overexpressed in human PC cell lines, mouse models, and human pancreatic tumors, and is associated with worse tumor grade and clinical outcomes. In PC cell lines, disruption/depletion of caveolae/Cav-1 reduces proliferation, colony formation, and invasion. Radiation and chemotherapy up-regulate Cav-1 expression, while Cav-1 depletion induces both chemosensitization and radiosensitization through altered apoptotic and DNA repair signaling. In vivo, Cav-1 depletion significantly attenuates tumor initiation and growth. Finally, Cav-1 depletion leads to altered JAK/STAT, JNK, and Src signaling in PC cells. Together, higher Cav-1 expression is correlated with worse outcomes, is essential for tumor growth and invasion (both in vitro and in vivo), is responsible for promoting resistance to therapies, and may serve as a prognostic/predictive biomarker and target in PC.

Stereotactic body radiation therapy in pancreatic cancer: the new frontier

Pancreatic cancer (PCA) remains a disease with a poor prognosis. The majority of PCA patients are unable to undergo surgical resection, which is the only potentially curative option at this time. A combination of chemotherapy and chemoradiation (CRT) are standard options for patients with locally advanced, unresectable disease, however, local control and patient outcomes remains poor. Stereotactic body radiation therapy (SBRT) is an emerging treatment option for PCA. SBRT delivers potentially ablative doses to the pancreatic tumor plus a small margin over a short period of time. Early studies with single-fraction SBRT demonstrated excellent tumor control with high rates of toxicity. The implementation of SBRT (3-5 doses) has demonstrated promising outcomes with favorable tumor control and toxicity rates. Herein we discuss the evolving role of SBRT in PCA treatment.

Definitive concurrent chemoradiotherapy in locally advanced pancreatic cancer

Purpose

Survival outcome of locally advanced pancreatic cancer has been poor and little is known about prognostic factors of the disease, especially in locally advanced cases treated with concurrent chemoradiation. This study was to analyze overall survival and prognostic factors of patients treated with concurrent chemoradiotherapy (CCRT) in locally advanced pancreatic cancer.

Materials and Methods

Medical records of 34 patients diagnosed with unresectable pancreatic cancer and treated with definitive CCRT, from December 2003 to December 2012, were reviewed. Median prescribed radiation dose was 50.4 Gy (range, 41.4 to 55.8 Gy), once daily, five times per week, 1.8 to 3 Gy per fraction.

Results

With a mean follow-up of 10 months (range, 0 to 49 months), median overall survival was 9 months. The 1- and 2-year survival rates were 40% and 10%, respectively. Median and mean time to progression were 5 and 7 months, respectively. Prognostic parameters related to overall survival were post-CCRT CA19-9 (p = 0.02), the Eastern Cooperative Oncology Group (ECOG) status (p < 0.01), and radiation dose (p = 0.04) according to univariate analysis. In multivariate analysis, post-CCRT CA19-9 value below 180 U/mL and ECOG status 0 or 1 were statistically significant independent prognostic factors associated with improved overall survival (p < 0.01 and p = 0.02, respectively).

Conclusion

Overall treatment results in locally advanced pancreatic cancer are relatively poor and few improvements have been accomplished in the past decades. Post-treatment CA19-9 below 180 U/mL and ECOG performance status 0 and 1 were significantly associated with an improved overall survival.