Adjuvant stereotactic body radiotherapy for resected pancreatic adenocarcinoma with close or positive margins. J Gastrointest Cancer. 2012;43:70-76. [PMID: 20809393 DOI: 10.1007/s12029-010-9203-7]

Impact of gut microbiome in the development and treatment of pancreatic cancer: Newer insights

The gut microbiome plays an important role in the variation of pharmacologic response. This aspect is especially important in the era of precision medicine, where understanding how and to what extent the gut microbiome interacts with drugs and their actions will be key to individualizing therapy. The impact of the composition of the gut microbiome on the efficacy of newer cancer therapies such as immune checkpoint inhibitors and chimeric antigen receptor T-cell treatment has become an active area of research. Pancreatic adenocarcinoma (PAC) has a poor prognosis even in those with potentially resectable disease, and treatment options are very limited. Newer studies have concluded that there is a synergistic effect for immunotherapy in combination with cytotoxic drugs, in the treatment of PAC. A variety of commensal microbiota can affect the efficacy of conventional chemotherapy and immunotherapy by modulating the tumor microenvironment in the treatment of PAC. This review will provide newer insights on the impact that alterations made in the gut microbial system have in the development and treatment of PAC.

Maximizing Tumor Control and Limiting Complications With Stereotactic Body Radiation Therapy for Pancreatic Cancer

PURPOSE

Stereotactic body radiation therapy (SBRT) and stereotactic ablative body radiation therapy is being increasingly used for pancreatic cancer (PCa), particularly in patients with locally advanced and borderline resectable disease. A wide variety of dose fractionation schemes have been reported in the literature. This HyTEC review uses tumor control probability models to evaluate the comparative effectiveness of the various SBRT treatment regimens used in the treatment of patients with localized PCa.

METHODS AND MATERIALS

A PubMed search was performed to review the published literature on the use of hypofractionated SBRT (usually in 1-5 fractions) for PCa in various clinical scenarios (eg, preoperative [neoadjuvant], borderline resectable, and locally advanced PCa). The linear quadratic model with α/β= 10 Gy was used to address differences in fractionation. Logistic tumor control probability models were generated using maximum likelihood parameter fitting.

RESULTS

After converting to 3-fraction equivalent doses, the pooled reported data and associated models suggests that 1-year local control (LC) without surgery is ≈79% to 86% after the equivalent of 30 to 36 Gy in 3 fractions, showing a dose response in the range of 25 to 36 Gy, and decreasing to less than 70% 1-year LC at doses below 24 Gy in 3 fractions. The 33 Gy in 5 fraction regimen (Alliance A021501) corresponds to 28.2 Gy in 3 fractions, for which the HyTEC pooled model had 77% 1-year LC without surgery. Above an equivalent dose of 28 Gy in 3 fractions, with margin-negative resection the 1-year LC exceeded 90%.

CONCLUSIONS

Pooled analyses of reported tumor control probabilities for commonly used SBRT dose-fractionation schedules for PCa suggests a dose response. These findings should be viewed with caution given the challenges and limitations of this review. Additional data are needed to better understand the dose or fractionation-response of SBRT for PCa.

Hypofractionated sequential radiotherapy boost: a promising strategy in inoperable locally advanced pancreatic cancer patients

PURPOSE

To investigate the potential benefits of a hypofractionated radiotherapy boost (HRB) after chemotherapy (CT) and concomitant chemoradiotherapy (CRT) in locally advanced pancreatic cancer (LAPC) patients. Primary endpoints were early and late toxicity, local control (LC) and pain-free progression (PFP) assessment. Two-years overall survival (OS), metastasis-free survival (MFS) and disease-free survival (DFS) were secondary endpoints.

MATERIALS AND METHODS

Patients (pts) affected by unresectable non-metastatic LAPC, previously treated with CT and CRT in upfront or sandwich setting, were selected for sequential HRB. Total prescribed dose was 30 Gy in 5 fractions (fr) to pancreatic primary lesion. Dose de-escalation was allowed in case of failure in respecting organs at risk constraints. Early and late toxicity were assessed according to CTCAE v.4.0 classification. The Kersh-Hazra scale was used for pain assessment. Local Control, PFP, MFS and DFS were calculated from the date of HRB to the date of relapse or the date of the last follow-up.

RESULTS

Thirty-one pts affected by unresectable, non-metastatic LAPC were consecutively enrolled from November 2004 to October 2019. All pts completed the planned HRB. Total delivered dose varied according to duodenal dose constraint: 20 Gy in 5 fr (N: 6; 19.4%), 20 Gy in 4 fr (N: 5; 16.2%), 25 Gy in 5 fr (N: 18; 58.0%) and 30 Gy in 6 fr (N: 2; 6.4%). Early and late toxicity were assessed in all pts: no Grade 3 or 4 acute gastrointestinal toxicity and no late gastrointestinal complications occurred. Median LC was 19 months (range 1-156) and 1- and 2-year PFP were 85% and 62.7%, respectively (median 28 months; range 2-139). According to the Kersh-Hazra scale, four pts had a Grade 3 and four pts had a Grade 1 abdominal pain before HRB. At the last follow-up only 3/31 pts had residual Grade 1 abdominal pain.Median MFS was 18 months (range 1-139). The 2-year OS after HRB was 57.4%, while 2-year OS from diagnosis was 77.3%.

CONCLUSION

Treatment intensification with hypofractionated radiotherapy boost is well tolerated in pts affected by unresectable LAPC previously treated with CT/CRT. Its rates of local and pain control are encouraging, supporting its introduction in clinical practice. Timing, schedule and dose of HRB need to be further investigated to personalize therapy and optimize clinical advantages.

Patterns of Failure After Adjuvant Stereotactic Body Radiation Therapy for Pancreatic Cancer With Close or Positive Margins

Purpose

There is no consensus on treatment volumes for adjuvant stereotactic body radiation therapy (SBRT) for pancreatic cancer. Herein, we report patterns of failure after pancreatic SBRT for close/positive margins, which may inform target volume design.

Methods and Materials

An institutional review board-approved retrospective review of patients with pancreatic adenocarcinoma treated with adjuvant SBRT for close/positive margins from 2009 to 2018 was conducted. Patterns of failure were defined as local (LF) within the tumor bed, regional (RF) within lymph nodes or anastomoses, or distant (DF). The cumulative incidence of locoregional failure was calculated using the cumulative incidence function accounting for the competing risk of death. LFs were mapped to the planning target volume (PTV) and classified as in-field (completely within the PTV), marginal (partially within the PTV), or out-of-field (completely outside the PTV). The location of LFs was compared with the Radiation Therapy Oncology Group 0848 contouring atlas to determine whether standard postoperative radiation therapy volumes would have included the LF.

Results

Seventy-six patients were treated with adjuvant SBRT for close (51.3%) or positive (48.7%) margins. Most (81.6%) received 36 Gy in 3 fractions, with a median PTV volume of 17.8 cc (interquartile range, 12.1-25.6). With a median follow-up of 17.0 months (interquartile range, 7.3-28.4), crude rates of first isolated LF, isolated RF, and DF +/- LF or RF were 9.2%, 6.6%, and 56.6%, respectively. Two-year cumulative incidences of LF, RF, locoregional failure, and DF were 34.9%, 30.8%, 49.2%, and 60.4%, respectively. Of 28 reviewable LFs, 21.4% were in-field while the remainder were completely outside (60.7%) or partially outside (17.9%) the PTV. Most LFs (92.9%) would have been encompassed by the Radiation Therapy Oncology Group consensus target volumes.

Conclusions

After adjuvant pancreatic SBRT for close/positive margins, the majority of LFs were outside the PTV but within contemporary target volumes for conventional radiation therapy.

Initial Results of a Prospective Study of Adjuvant Pancreatic Stereotactic Body Radiation Therapy for Close or Positive Margins

Purpose

Patients with close or positive margins after surgery for pancreatic carcinoma are at a high risk for recurrence. Stereotactic body radiation therapy (SBRT) allows for safe dose escalation with great conformity and short duration of treatment. Herein, we report the initial results of a prospective observational study that evaluated the efficacy and safety of this treatment option.

Methods and Materials

Patients eligible for the study had pathologically proven T1-4N0-1M0 pancreatic adenocarcinoma with a positive margin (≤1 mm) or a close margin defined as <2.5 mm. Patients were treated with either neoadjuvant or adjuvant chemotherapy, if eligible for systemic therapy. All patients received 36 Gy in 3 fractions to the close or positive margin site.

Results

From February 2013 to January 2018, 50 patients were enrolled with 49 patients treated on protocol and included in the analysis. The median age was 71 years. The median clinical target volume was 11.3 cc and median planning target volume 22.0 cc. The median overall survival was 23.7 months (95% confidence interval, 13.6-33.8). Local progression-free survival at 1 and 2 years was 85% and 77%, respectively. Regional progression-free survival at 1 and 2 years was 73% and 73%, respectively. Distant metastases-free survival was 57% and 49% at 1 and 2 years, respectively. Grade 3+ radiation toxicity was only 4.1% and occurred in 2 patients.

Conclusions

Adjuvant pancreatic SBRT was shown to be a safe and feasible treatment option for patients with high-risk pancreatic adenocarcinoma and close or positive margins. This is the first prospective study of SBRT in high-risk postoperative pancreatic cancer. Our results yielded significant local and regional control with low rates of acute toxicity. This technique does not interrupt the administration of systemically dosed multiagent chemotherapy and can be safely interdigitated between cycles because SBRT is only 1 week of treatment.

Effects of chemoradiotherapy and chemotherapy on survival of patients with locally advanced pancreatic cancer: A meta-analysis of randomized controlled trials

To comparatively evaluate chemoradiotherapy (CRT) and chemotherapy (CT) for the treatment of locally advanced pancreatic cancer (LAPC) by meta-analysis.A literature search was performed until August 2016 to identify comparative studies assessing survival rates and complications. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were determined with the fixed or random effects model.Five randomized controlled trials (RCTs) met the defined inclusion criteria. A total of 593 patients were included, with 295 and 298 treated with CRT and CT, respectively. Overall survival showed no statistically significant difference in patients treated with CRT and CT at 6, 12, 18, and 24 months (respectively: OR = 1.13, 95% CI: 0.60-2.17; OR = 1.15, 95% CI: 0.53-2.52; OR = 1.13, 95% CI: 0.43-2.95; OR = 1.07, 95% CI: 0.67-1.72). Meanwhile, CRT had higher rates of grade 3 to 4 adverse events (nausea and vomiting, OR = 2.74, 95% CI: 1.36-5.52; diarrhea, OR = 4.28, 95% CI: 1.16-15.71).The data are not sufficient to change from CT to CRT in the treatment of patients with LAPC and thus clinical discretion is required until more data is accumulated.

Adjuvant therapeutic strategies for resectable pancreatic adenocarcinoma

Of all patients diagnosed with pancreatic adenocarcinoma, only 15-20% present with resectable disease. Despite curative-intent resection, the prognosis remains poor with the majority of patients recurring, prompting the need for adjuvant therapy. Historical data support the use of adjuvant 5-fluorouracil (5-FU) or gemcitabine, but recent data suggest either gemcitabine plus capecitabine or modified FOLFIRINOX can improve overall survival when compared to gemcitabine alone. The use of adjuvant chemoradiation therapy remains controversial, primarily due to limitations in study design and mixed results of historical trials. The ongoing Radiation Therapy Oncology Group (RTOG)-0848 trial hopes to further define the role of adjuvant chemoradiation therapy. Intraoperative radiation therapy (IORT) and adjuvant immunotherapy represent additional possibilities to improve outcomes, but evidence supporting their use is limited. This article reviews adjuvant therapeutic strategies for resectable pancreatic adenocarcinoma, including chemotherapy, chemoradiation therapy, IORT and immunotherapy.

Stereotactic body radiotherapy (SBRT) for patients with locally advanced pancreatic cancer: A single center experience

INTRODUCTION

Despite advances in treatment, notably in systemic therapy, the prognosis of pancreatic adenocarcinoma (PADC) remains dismal. Stereotactic body radiotherapy (SBRT) is an emerging tool in the complex management of PADC. We review outcomes of SBRT for PADC at our institution.

METHODS

We reviewed patients treated with SBRT for either unresectable PADC or locally recurrent PADC after surgery. Treatment was delivered using a robotic radiosurgery system with respiratory tracking. The median prescribed dose was 30 Gy (30-35 Gy), delivered in 5-6 fractions. Toxicities were reported as per CTCAE v4.0. Survival was estimated using the Kaplan-Meier method.

RESULTS

Between October 2010 and March 2016, 21 patients were treated at our institution. The median follow-up was 7 months (range: 1-28). The 1-year local control rate was 57%. The 1-year overall survival was 25% for locally advanced patients and 67% for those with local recurrences (p = 0.27). Eighty percent of cancer related deaths were due to metastatic progression. Five patients (24%) had Grade I-II gastrointestinal acute toxicity; one patient had fatal gastrointestinal bleeding 6 months after SBRT.

CONCLUSION

In PADC, fractionated SBRT dose schedules near 30 Gy may strike the best balance of local control and bowel toxicity. More work is required to integrate pancreatic SBRT with modern systemic therapy.

Postresection CA19-9 and margin status as predictors of recurrence after adjuvant treatment for pancreatic carcinoma: Analysis of NRG oncology RTOG trial 9704

Purpose

NRG Oncology RTOG 9704 was the first adjuvant trial to validate the prognostic value of postresection CA19-9 levels for survival in patients with pancreatic carcinoma. The data resulting from this study also provide information about predictors of recurrence that may be used to tailor individualized management in this disease setting. This secondary analysis assessed the prognostic value of postresection CA19-9 and surgical margin status (SMS) in predicting patterns of disease recurrence.

Methods and materials

This multicenter cooperative trial included participants who were enrolled as patients at oncology treatment sites in the United States and Canada. The study included 451 patients analyzable for SMS, of whom 385 were eligible for postresection CA19-9 analysis. Postresection CA19-9 was analyzed at cut points of 90, 180, and continuously. Patterns of disease recurrence included local/regional recurrence (LRR) and distant failure (DF). Multivariable analyses included treatment, tumor size, and nodal status. To adjust for multiple comparisons, a P value of ≤ .01 was considered statistically significant and > .01 to ≤ .05 to be a trend.

Results

For CA19-9, 132 (34%) patients were Lewis antigen-negative (no CA19-9 expression), 200 (52%) had levels <90, and 220 (57%) had levels <180. A total of 188 patients (42%) had negative margins, 152 (34%) positive, and 111 (25%) unknown. On univariate analysis, CA19-9 cut at 90 was associated with increases in LRR (trend) and DF. Results were similar at the 180 cut point. SMS was not associated with an increase in LRR on univariate or multivariate analyses. On multivariable analysis, CA19-9 ≥ 90 was associated with increased LRR and DF. Results were similar at the 180 cut point.

Conclusions

In this prospective evaluation, postresection CA19-9 was a significant predictor of both LRR and DF, whereas SMS was not. These findings support consideration of adjuvant radiation therapy dose intensification in patients with elevated postresection CA19-9.

The role of imaging in the clinical practice of radiation oncology for pancreatic cancer

Advances in technology have enabled the delivery of high doses of radiation therapy for pancreatic ductal adenocarcinoma (PDAC) with low rates of toxicity. Although the role of radiation for pancreatic cancer continues to evolve, encouraging results with newer techniques indicate that radiation may benefit selected patient populations. Imaging has been central to the modern successes of radiation therapy for PDAC. Here, we review the role of diagnostic imaging, imaging-based planning, and image guidance in radiation oncology practice for PDAC.

Redefining the Positive Margin in Pancreatic Cancer: Impact on Patterns of Failure, Long-Term Survival and Adjuvant Therapy

PURPOSE

There is debate regarding the definition and clinical significance of margin clearance in pancreatic ductal adenocarcinoma (PDA). A comprehensive archival analysis of surgical resection margins was performed to determine the effect on locoregional recurrence and survival, and the impact of adjuvant therapy in PDA.

METHODS

We identified 105 patients with resected PDA. Pancreatic, anterior, bile duct, and posterior surgical resection margins (PM; posterior surface, uncinate and vascular groove) were identified. Three pathologists reviewed all archival surgical specimens and recategorized each margin as tumor at ink/transected, <0.5, 0.5-1, >1-2, or >2 mm from the inked surface. The impact of these and other clinical variables was assessed on local control, disease-free survival (DFS), and overall survival (OS).

RESULTS

Among all margins, PM clearance up to 2 mm was prognostic of DFS (p = 0.01) and OS (p = 0.01). Dichotomizing the PM at 2 mm revealed it to be an independent predictor of local recurrence-free survival [hazard ratio HR] 0.20, 95% confidence interval [CI] 0.048-0.881, p = 0.033), DFS (HR 0.46, 95% CI 0.22-0.96, p = 0.03), and OS (HR 0.31, 95% CI 0.14-0.74, p = 0.008). A margin status of >2 mm was also prognostic of OS in patients who received adjuvant chemotherapy (HR 0.31, 95% CI 0.11-0.89, p = 0.03), however this difference was mitigated in patients receiving adjuvant chemoradiotherapy (HR 0.40, 95% CI 0.10-1.58, p = 0.19).

CONCLUSION

These data highlight the clinical significance of the PM and the lack of significance of other resection margins. Clearance in excess of 2 mm should be considered to improve long-term clinical outcomes. The use of adjuvant radiotherapy should be strongly considered in patients with PMs <2 mm.

Stereotactic Body Radiation Therapy for Pancreatic Cancer

The role of radiation therapy in the management of pancreatic cancer represents an area of some controversy. However, local disease progression remains a significant cause of morbidity and even mortality for patients with this disease. Stereotactic body radiotherapy (SBRT) is an emerging treatment option for pancreatic cancer, primarily for locally advanced (unresectable) disease as it can provide a therapeutic benefit with significant advantages for patients' quality of life over standard conventional chemoradiation. There may also be a role for SBRT as neoadjuvant therapy for patients with borderline resectable disease to allow conversion to resectability. The objective of this review is to present the data supporting SBRT in pancreatic cancer as well as the potential limitations and caveats of current studies.

A margin distance analysis of the impact of adjuvant chemoradiation on survival after pancreatoduodenectomy for pancreatic adenocarcinoma

BACKGROUND

The role of adjuvant chemoradiotherapy (CRT) following pancreaticoduodenectomy (PD) for pancreatic adenocarcinoma (PDA) remains controversial. Recent data suggest that increased margin clearance (MC: distance between tumor and cut surface) is associated with improved survival after PD, but the role of adjuvant CRT in patients with known MC is undefined. We sought to delineate the impact of adjuvant CRT on survival based on MC following PD.

METHODS

Patients who underwent PD for PDA between 2002 and 2014 were retrospectively stratified into three groups based on MC: 0 mm, ≤1 mm, and >1 mm. The impact of CRT on survival in each MC group was determined by univariate and multivariate analysis.

RESULTS

Three hundred and ten patients with known MC were analyzed (0 mm =67, ≤1 mm =113, and >1 mm =130). Increasing MC was independently associated with improved OS (≤1 mm, HR 0.66, 95% CI 0.46-0.96, P=0.03; >1 mm, HR 0.51, 95% CI 0.35-0.75, P=0.001; compared to 0 mm). Adjuvant CRT was administered to 62 patients (20%). On margin-stratified multivariate analysis, adjuvant CRT was independently associated with increased OS in patients with ≤1 mm margins (HR 0.36; 95% CI 0.18-0.69, P=0.002) but not for 0 mm and >1 mm margins.

CONCLUSIONS

This analysis suggests that the benefit of adjuvant CRT may be restricted to patients with ≤1 mm MC after PD for pancreatic cancer.

The Role of Radiation Therapy for Pancreatic Cancer in the Adjuvant and Neoadjuvant Settings

Pancreatic cancer is the third leading cause of cancer-related death in the United States. Although surgery remains the only curative treatment, chemotherapy and radiation therapy are frequently used. In the adjuvant setting, radiation is usually delivered with chemotherapy to eradicate residual microscopic or macroscopic disease in the resection bed. Neoadjuvant radiation therapy has become more frequently utilized. This article reviews the historical and modern literature regarding radiation therapy in the neoadjuvant and adjuvant settings, focusing on the evolution of radiation therapy techniques and clinical trials in an attempt to identify patients best suited to receiving radiation therapy.

A current perspective on stereotactic body radiation therapy for pancreatic cancer

Pancreatic cancer is a formidable malignancy with poor outcomes. The majority of patients are unable to undergo resection, which remains the only potentially curative treatment option. The management of locally advanced (unresectable) pancreatic cancer is controversial; however, treatment with either chemotherapy or chemoradiation is associated with high rates of local tumor progression and metastases development, resulting in low survival rates. An emerging local modality is stereotactic body radiation therapy (SBRT), which uses image-guided, conformal, high-dose radiation. SBRT has demonstrated promising local control rates and resultant quality of life with acceptable rates of toxicity. Over the past decade, increasing clinical experience and data have supported SBRT as a local treatment modality. Nevertheless, additional research is required to further evaluate the role of SBRT and improve upon the persistently poor outcomes associated with pancreatic cancer. This review discusses the existing clinical experience and technical implementation of SBRT for pancreatic cancer and highlights the directions for ongoing and future studies.

Stereotactic body radiotherapy for renal cell cancer and pancreatic cancer : Literature review and practice recommendations of the DEGRO Working Group on Stereotactic Radiotherapy

PURPOSE

This report of the Working Group on Stereotactic Radiotherapy of the German Society of Radiation Oncology (DEGRO) aims to provide a literature review and practice recommendations for stereotactic body radiotherapy (SBRT) of primary renal cell cancer and primary pancreatic cancer.

METHODS

A literature search on SBRT for both renal cancer and pancreatic cancer was performed with focus on prospective trials and technical aspects for clinical implementation.

RESULTS

Data on renal and pancreatic SBRT are limited, but show promising rates of local control for both treatment sites. For pancreatic cancer, fractionated SBRT should be preferred to single-dose treatment to reduce the risk of gastrointestinal toxicity. Motion-compensation strategies and image guidance are paramount for safe SBRT delivery in both tumor entities.

CONCLUSION

SBRT for renal cancer and pancreatic cancer have been successfully evaluated in phase I and phase II trials. Pancreatic SBRT should be practiced carefully and only within prospective protocols due to the risk of severe gastrointestinal toxicity. SBRT for primary renal cell cancer appears a viable option for medically inoperable patients but future research needs to better define patient selection criteria and the detailed practice of SBRT.

Individually optimized stereotactic radiotherapy for pancreatic head tumors: A planning feasibility study

AIM

Aim of this study was to perform a planning feasibility analysis of a 3-level dose prescription using an IMRT-SIB technique.

BACKGROUND

Radiation therapy of locally advanced pancreatic cancer should administer a minimum dose to the duodenum and a very high dose to the vascular infiltration areas to improve the possibility of a radical resection.

MATERIALS AND METHODS

Fifteen patients with pancreatic head adenocarcinoma and vascular involvement were included. The duodenal PTV (PTVd) was defined as the GTV overlapping the duodenal PRV. Vascular CTV (CTVv) was defined as the surface of contact or infiltration between the tumor and vessel plus a 5 mm margin. Vascular PTV (PTVv) was considered as the CTVv plus an anisotropic margin. The tumor PTV (PTVt) was defined as the GTV plus a margin including the PTVv and excluding the PTVd. The following doses were prescribed: 30 Gy (6 Gy/fraction) to PTVd, 37.5 Gy (7.5 Gy/fraction) to PTVt, and 45 Gy (9 Gy/fraction) to PTVv, respectively. Treatment was planned with an IMRT technique.

RESULTS

The primary end-point (PTVv D_mean > 90%) was achieved in all patients. PTVv D_98% > 90% was achieved in 6 patients (40%). OARs constraints were achieved in all patients.

CONCLUSIONS

Although the PTVv D_95% > 95% objective was achieved only in 40% of patients, the study showed that in 100% of patients it was possible to administer a strongly differentiated mean/median dose. Prospective trials based on clinical application of this strategy seem to be justified in selected patients without overlap between PTVd and PTVv.

Stereotactic body radiotherapy for pancreatic cancer: recent progress and future directions

Despite advances in surgical, medical, and radiation therapy for pancreatic cancer, the prognosis remains poor. At this time, the only chance for long-term survival is surgical resection. More challenging is the optimal management of unresectable locally advanced pancreatic cancer, which has historically been treated with concurrent chemoradiation or chemotherapy alone. However, the survival and local control benefit of conventional radiotherapy in addition to chemotherapy was unclear. More recently, stereotactic body radiotherapy (SBRT) is emerging as a viable approach to maximizing local tumor control with a tolerable side effect profile. SBRT achieves sharp dose fall-off facilitating safe delivery of highly focused radiation to the tumor over 1-5 days. Although the optimal regimen of pancreas SBRT has not yet been established, its short treatment course limits the delay of additional. Future directions involve prospective study of pancreas SBRT and exploration of biomarkers and imaging technology in order to adopt a personalized management paradigm.

Advances of stereotactic body radiotherapy in pancreatic cancer

Pancreatic cancer (PCA) is one of the most aggressive tumors with few effective treatment modalities. It is the 4th and 7th leading cause of cancer death in the United States and China, respectively. At the time of diagnosis, only 20% of cases present with a resectable tumor, and about 40% with a locally advanced tumor that is considered unresectable. Even resected patients still have a poor prognosis, with an incidence of local recurrence ranging from 20% to 60%. It is also reported that up to 30% of PCA patients die from locally obstructive disease with few or no distant metastases. These findings have highlighted the importance of local radiation therapy in the treatment of PCA. As the role of conventional chemoradiotherapy remains controversial, the dawn of the pancreas stereotactic body radiation therapy (SBRT) era represents a potential paradigm shift in the management of PCA. SBRT delivers a higher biological effective dose to the tumor with sharp dose escalation in a shorter treatment time course. Pancreas SBRT is a novel therapeutic option to achieve local tumor control with minimal toxicity. Herein, we review the advancement of SBRT for PCA patients with different stages of pancreatic adenocarcinoma.

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.

Robotic radiosurgery in pancreatic cancer: A systematic review

AIM: To present a systematic review of techniques and clinical results.

METHODS: A systematic review of published literature was performed. Only studies reporting patient outcome after radiosurgery (single fraction) delivered with robotic devices [i.e., robotic radiosurgery (RRS)] have been analyzed.

RESULTS: A total of 96 patients from 5 studies were included. The studies are characterized by small series and different methods in terms of dose, target definition, combination with chemotherapy and/or standard fractionated radiotherapy and evaluation modalities. Preliminary results are positive in terms of tumor response (ORR = 56%) and local control of the tumor (crude rate of local progressions: 19.5%). Results for median overall survival (11.4 mo) seem comparable with the ones of prolonged chemoradiation (range: 8.6-13.0 mo). However, gastrointestinal toxicity seems to be the main limitation of RRS, especially at the duodenal level.

CONCLUSION: RRS allows for local treatment in a shortened time (1 fraction) compared to traditional treatments (about 1 mo), providing the possibility for an easy integration with systemic therapies. Preliminary results did not show any outcome differences compared to standard chemoradiation. Thus, further efforts to reduce gastrointestinal toxicity are strongly needed.

Adjuvant radiation therapy for pancreatic cancer: a review of the old and the new

Surgery represents the only potential curative treatment option for patients diagnosed with pancreatic adenocarcinoma. Despite aggressive surgical management for patients deemed to be resectable, rates of local recurrence and/or distant metastases remain high, resulting in poor long-term outcomes. In an effort to reduce recurrence rates and improve survival for patients having undergone resection, adjuvant therapies (ATs) including chemotherapy and chemoradiation therapy (CRT) have been explored. While adjuvant chemotherapy has been shown to consistently improve outcomes, the data regarding adjuvant radiation therapy (RT) is mixed. Although the ability of radiation to improve local control has been demonstrated, it has not always led to improved survival outcomes for patients. Early trials are flawed in their utilization of sub-optimal radiation techniques, limiting their generalizability. Recent and ongoing trials incorporate more optimized RT approaches and seek to clarify its role in treatment strategies. At the same time novel radiation techniques such as intensity modulated RT (IMRT) and stereotactic body RT (SBRT) are under active investigation. It is hoped that these efforts will lead to improved disease-related outcomes while reducing toxicity rates.

Pancreatic cancer and SBRT: A new potential option?

Local control remains a major issue for patients with unresectable, locally advanced pancreatic cancer (LAPC). The role of radiation therapy in the management of LAPC represents an area of some controversy. Stereotactic body radiotherapy is an emerging treatment option for LAPC as it can provide a therapeutic benefit with significant advantages for patients' quality of life over standard conventional chemoradiation. The objective of this review is to present the rationale for stereotactic body radiotherapy in LAPC, as well as to discuss the potential limitations and caveats of the currently available studies.

SBRT in pancreatic cancer: what is the therapeutic window?

PURPOSE/OBJECTIVE

To analyse outcome and toxicity of stereotactic body radiotherapy (SBRT) in pancreatic cancer (PDAC).

MATERIAL/METHODS

We systematically reviewed full reports on outcome and toxicity transforming prescription doses to equivalent doses of 2 Gy (EQD2) and biological equivalent doses (BED). Pearson product-moment correlation coefficient, regression analysis and Lyman-Kutcher-Burman modelling were used.

RESULTS

Sixteen trials (572 patients) were identified. Local control correlated with dose. Additionally 4 upper gastrointestinal-SBRT trials (149 patients) were included for toxicity analysis. Acute toxicity was mild but late toxicity ⩾G2 was substantial and predominantly gastrointestinal. Late toxicity ⩾G2 and ⩾G3 correlated highly with EQD2/BED after linear (R(2)=0.85 and 0.77, respectively) and Lyman-Kutcher-Burman modelling. Linear regression lines indicated ⩾G2 and ⩾G3 toxicity frequencies of 5% at 65 Gy and 80 Gy EQD2-α/β=3, respectively. A comparison of toxicity with dose constraints for duodenum revealed partly inadequate dose constraints.

CONCLUSION

RESULTS from multiple fraction regimens could be successfully interpreted to estimate toxicity according to EQD2/BED prescription doses, and dose constraints for the duodenum were derived, whereas local control appeared to be less dose-dependent. This analysis may be useful to plan clinical trials for SBRT and hypofractionated radiotherapy in pancreatic cancer.

The role of radiation therapy in pancreatic ductal adenocarcinoma in the neoadjuvant and adjuvant settings

Pancreatic adenocarcinoma (PCA) is associated with high rates of cancer-related morbidity and mortality. Yet despite modern treatment advances, the only curative therapy remains surgical resection. The adjuvant therapeutic standard of care for PCA in the United States includes both chemotherapy and chemoradiation; however, an optimal regimen has not been established. For patients with resectable and borderline resectable PCA, recent investigation has focused efforts on evaluating the feasibility and efficacy of neoadjuvant therapy. Neoadjuvant therapy allows for early initiation of systemic therapy and identification of patients who harbor micrometastatic disease, thus sparing patients the potential morbidities associated with unnecessary radiation or surgery. This article critically reviews the data supporting or refuting the role of radiation therapy in the neoadjuvant and adjuvant settings of PCA management, with a particular focus on determining which patients may be more likely to benefit from radiation therapy.

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.

Therapeutic options for the management of pancreatic cancer

Since its initial characterization, pancreatic ductal adenocarcinoma has remained one of the most devastating and difficult cancers to treat. Pancreatic cancer is the fourth leading cause of death in the United States, resulting in an estimated 38460 deaths annually. With few screening tools available to detect this disease at an early stage, 94% of patients will die within five years of diagnosis. Despite decades of research that have led to a better understanding of the molecular and cellular signaling pathways in pancreatic cancer cells, few effective therapies have been developed to target these pathways. Other treatment options have included more sophisticated pancreatic cancer surgeries and combination therapies. While outcomes have improved modestly for these patients, more effective treatments are desperately needed. One of the greatest challenges in the future of treating this malignancy will be to develop therapies that target the tumor microenvironment and surrounding pancreatic cancer stem cells in addition to pancreatic cancer cells. Recent advances in targeting pancreatic stellate cells and the stroma have encouraged researchers to shift their focus to the role of desmoplasia in pancreatic cancer pathobiology in the hopes of developing newer-generation therapies. By combining novel agents with current cytotoxic chemotherapies and radiation therapy and personalizing them to each patient based on specific biomarkers, the goal of prolonging a patient’s life could be achieved. Here we review the most effective therapies that have been used for the treatment of pancreatic cancer and discuss the future potential of therapeutic options.

Adjuvant chemoradiation for pancreatic cancer: what does the evidence tell us?

The role of adjuvant chemoradiation (CRT) for pancreas cancer remains unclear. A handful of randomized trials conducted decades of ago ignited a debate that continues today about whether CRT improves survival after surgery. The many flaws in these trials are well described in the literature, which include the use of antiquated radiation delivery techniques and suboptimal doses. Recent prospective randomized data is lacking, and we eagerly await the results the ongoing Radiation Therapy Oncology Group (RTOG) 0848 trial that is evaluating the utility of high quality adjuvant CRT in resected pancreas cancer patients. Until the results of RTOG 0848 are available we should look to other studies from the modern era to guide adjuvant treatment recommendations. Here we review the current state of the art for adjuvant pancreas CRT with respect to patient selection, radiation techniques, radiation dose, and integration with novel systemic agents.

Mapping patterns of local recurrence after pancreaticoduodenectomy for pancreatic adenocarcinoma: a new approach to adjuvant radiation field design

PURPOSE

To generate a map of local recurrences after pancreaticoduodenectomy (PD) for patients with resectable pancreatic ductal adenocarcinoma (PDA) and to model an adjuvant radiation therapy planning treatment volume (PTV) that encompasses a majority of local recurrences.

METHODS AND MATERIALS

Consecutive patients with resectable PDA undergoing PD and 1 or more computed tomography (CT) scans more than 60 days after PD at our institution were reviewed. Patients were divided into 3 groups: no adjuvant treatment (NA), chemotherapy alone (CTA), or chemoradiation (CRT). Cross-sectional scans were centrally reviewed, and local recurrences were plotted to scale with respect to the celiac axis (CA), superior mesenteric artery (SMA), and renal veins on 1 CT scan of a template post-PD patient. An adjuvant clinical treatment volume comprising 90% of local failures based on standard expansions of the CA and SMA was created and simulated on 3 post-PD CT scans to assess the feasibility of this planning approach.

RESULTS

Of the 202 patients in the study, 40 (20%), 34 (17%), and 128 (63%) received NA, CTA, and CRT adjuvant therapy, respectively. The rate of margin-positive resections was greater in CRT patients than in CTA patients (28% vs 9%, P=.023). Local recurrence occurred in 90 of the 202 patients overall (45%) and in 19 (48%), 22 (65%), and 49 (38%) in the NA, CTA, and CRT groups, respectively. Ninety percent of recurrences were within a 3.0-cm right-lateral, 2.0-cm left-lateral, 1.5-cm anterior, 1.0-cm posterior, 1.0-cm superior, and 2.0-cm inferior expansion of the combined CA and SMA contours. Three simulated radiation treatment plans using these expansions with adjustments to avoid nearby structures were created to demonstrate the use of this treatment volume.

CONCLUSIONS

Modified PTVs targeting high-risk areas may improve local control while minimizing toxicities, allowing dose escalation with intensity-modulated or stereotactic body radiation therapy.

Stereotactic body radiotherapy in the treatment of pancreatic adenocarcinoma in elderly patients

Background

Treatment of pancreatic adenocarcinoma in the elderly is often complicated by comorbidities that preclude surgery, chemotherapy and/or conventional external beam radiation therapy (EBRT). Stereotactic body radiotherapy (SBRT) has thus garnered interest in this setting.

Methods

A retrospective review of 26 patients of age ≥ 80 with pancreatic adenocarcinoma treated with definitive SBRT+/-chemotherapy from 2007–2011 was performed. Twenty-seven percent of patients were stage I, 38% were stage II, 27% were stage III and 8% were stage IV. Patients most commonly received 24 Gy/1 fraction or 30-36 Gy/3 fractions. Kaplan-Meier was used to estimate overall survival (OS), local control (LC), cause specific survival (CSS) and freedom-from-metastatic disease (FFMD).

Results

The median age was 86 (range 80–91), and median follow-up was 11.6 months (3.5-24.6). The median planning target volume was 21.48 cm³ (6.1-85.09). Median OS was 7.6 months with 6/12 month OS rates of 65.4%/34.6%, respectively. Median LC was 11.5 months, 6-month and 12-month actuarial LC rates were 60.1% and 41.2%, respectively. There were no independent predictors for LC, but there was a trend for improved LC with prescription dose greater than 20 Gy (p = 0.063). Median CSS was 6.3 months, and 6-month and 12-month actuarial CSS were 53.8% and 23.1%, respectively. Median FFMD was 8.4 months, and 6-month and 12-month actuarial rates were 62.0% and 41.4%, respectively. Nine patients (47%) had local failures, 11 (58%) had distant metastasis, and 7 (37%) had both. There were no acute or late grade 3+ toxicities.

Conclusions

Definitive SBRT is feasible, safe and effective in elderly patients who have unresectable disease, have comorbidities precluding surgery or decline surgery.

Pancreatic cancer: chemotherapy and radiotherapy

Pancreatic cancer in many cases appears in a non-curatively resectable stage when the diagnosis is made. Palliative treatment become an option in the patients with advanced stage. The present article reviewed chemotherapy and radiotherapy in various advanced stage of pancreatic cancer.

Impact of omission of elective nodal irradiation on treatment outcomes in locally advanced pancreatic adenocarcinoma patients treated with definitive concurrent chemoradiotherapy

BACKGROUND

We evaluated influence of limited-field radiotherapy with no elective nodal irradiation (ENI) on outcomes and toxicity profile in patients with locally advanced pancreatic adenocarcinoma (LAPAC), treated with definitive concurrent chemoradiotherapy (C-CRT).

METHODS

Thirty-five patients with histological proof of LAPAC underwent 50.4Gy of C-CRT with 5-FU followed by maintenance gemcitabine. Target volume included primary tumor and lymph nodes that appeared to be involved on either contrast-enhanced computerized tomography or 18F-fluoro-deoxyglucose positron emission tomography.

RESULTS

No grade 4/5 acute/late toxicity was reported at median 15.7 months. Acute hematologic plus non-hematologic grade 3 toxicity was noted in 10 (28.6%) patients. At long-term, 2 patients (5.7%) experienced grade 3 gastric outlet obstructions at 8.7 and 10.9 months, respectively. No isolated regional relapses were noted. Median overall-survival (OS), progression-free survival (PFS), and locoregional-PFS (LRPFS) were 15.2, 9.1 and 7.3 months, respectively. Corresponding 1- and 2-year survival estimates were 60.0% and 20.0% for OS, 41.9% and 17.4% for LRPFS, and 34.0% and 12.7% for PFS, respectively.

CONCLUSIONS

Compared to ENI literature, first report of a limited-field C-CRT study carried out in Turkey showed that omission of ENI was relatively well tolerated without compromising survival and locoregional control rates in patients with LAPAC.

Role of radiation therapy in the management of pancreatic cancer

Local failure remains a major issue for patients with both resectable and locally advanced pancreatic cancer. The role of radiation therapy in the management of this disease is less clear and represents an area of some controversy. The objective of this review is to present the rationale for radiation therapy in pancreatic cancer, as well as to discuss the potential limitations and caveats of the currently available studies.

Local recurrence of pancreatic cancer after primary surgical intervention: how to deal with this devastating scenario?

The dismal prognosis of pancreatic cancer reflects into the increased recurrence rate, even after R0 pancreaticoduodenectomy. Although, conventional radiation-, chemo- or surgical therapy in much selected cases, seem to work out favorably long term, less invasive and non-toxic methods with more immediate results are always preferred, concerning the already aggravated status of this group of patients. We present hereby a comprehensive review of the literature concerning the treatment of recurrent pancreatic cancer based on the case of a patient who 20 months after a pancreaticoduodenectomy developed portal hypertension and symptomatic first degree esophageal, gastric and mesenteric varices, caused by the nearly complete splenic vein obstruction at the portal vein confluence. The varices were revascularized by a percutaneous transhepatic placement of an endovascular stent into the splenic vein, along with a sequent stereotactic body radiation therapy for the local tumor control. Thanks to the accuracy and safety of the present combined treatment, the patient one year later presents control of the disease and its complications. Our paper is the first in the international literature that tries to review all the treatment modalities available (surgical, adjuvant, neoadjuvant and palliative therapy) and their efficacy, concerning the locally recurrent pancreatic cancer; furthermore, we tried to analyze the application of the above mentioned combined therapeutic approach in similar cases, elucidating simultaneously all the questions that arise. The limited existing data in the international literature and the lack of randomized controlled trials make this effort difficult, but the physician should be aware after all of all the available and innovative treatment modalities, before he chooses one. Finally, we would like to emphasize the fact that not only the local control but also the management of the complications are important for a prolonged median survival and a better quality of life after all.