Intraoperative Radiotherapy in the Era of Intensive Neoadjuvant Chemotherapy and Chemoradiotherapy for Pancreatic Adenocarcinoma

Consensus, debate, and prospective on pancreatic cancer treatments

Pancreatic cancer remains one of the most aggressive solid tumors. As a systemic disease, despite the improvement of multi-modality treatment strategies, the prognosis of pancreatic cancer was not improved dramatically. For resectable or borderline resectable patients, the surgical strategy centered on improving R0 resection rate is consensus; however, the role of neoadjuvant therapy in resectable patients and the optimal neoadjuvant therapy of chemotherapy with or without radiotherapy in borderline resectable patients were debated. Postoperative adjuvant chemotherapy of gemcitabine/capecitabine or mFOLFIRINOX is recommended regardless of the margin status. Chemotherapy as the first-line treatment strategy for advanced or metastatic patients included FOLFIRINOX, gemcitabine/nab-paclitaxel, or NALIRIFOX regimens whereas 5-FU plus liposomal irinotecan was the only standard of care second-line therapy. Immunotherapy is an innovative therapy although anti-PD-1 antibody is currently the only agent approved by for MSI-H, dMMR, or TMB-high solid tumors, which represent a very small subset of pancreatic cancers. Combination strategies to increase the immunogenicity and to overcome the immunosuppressive tumor microenvironment may sensitize pancreatic cancer to immunotherapy. Targeted therapies represented by PARP and KRAS inhibitors are also under investigation, showing benefits in improving progression-free survival and objective response rate. This review discusses the current treatment modalities and highlights innovative therapies for pancreatic cancer.

Portal Vein or Superior Mesenteric Vein Thrombosis with Dose-Escalated Radiation for Borderline or Locally Advanced Pancreatic Cancer

PURPOSE

Portal vein and superior mesenteric vein thrombosis (PVT/SMVT) are potentially morbid complications of radiation dose-escalated local therapy for pancreatic cancer. We retrospectively reviewed records for patients treated with and without intraoperative radiation (IORT) to identify risk factors for PVT/SMVT.

METHODS

Ninety-six patients with locally advanced or borderline resectable pancreatic adenocarcinoma received neoadjuvant therapy followed by surgical exploration from 2009 to 2014. Patients at risk for close or positive surgical margins received IORT boost to a biologically effective dose (BED10) > 100. Prognostic factors for PVT/SMVT were evaluated using competing risks regression.

RESULTS

Median follow-up was 79 months for surviving patients. Fifty-six patients (58%) received IORT. Twenty-nine patients (30%) developed PVT/SMVT at a median time of 18 months. On univariate competing risks regression, operative blood loss and venous repair with a vascular interposition graft, but not IORT dose escalation or diabetes history, were significantly associated with PVT/SMVT. The development of thrombosis in the absence of recurrence was significantly associated with a longstanding diabetes history, post-neoadjuvant treatment CA19-9, and operative blood loss. All 4 patients who underwent both IORT and vascular repair with a graft developed PVT/SMVT. PVT/SMVT in the absence of recurrence is not associated with significantly worsened overall survival but led to frequent medical interventions.

CONCLUSIONS

Approximately 30% of patients who underwent neoadjuvant chemoradiation for PDAC developed PVT/SMVT a median of 18 months following surgery. This was significantly associated with venous reconstruction with vascular grafts, but not with escalating radiation dose. PVT/SMVT in the absence of recurrence was associated with significant morbidity.

Multiagent Chemotherapy and Stereotactic Body Radiation Therapy in Patients with Unresectable Pancreatic Adenocarcinoma: A Prospective Nonrandomized Controlled Trial

PURPOSE

In a prospective multicenter study, gemcitabine monotherapy followed by stereotactic body radiation therapy (SBRT) was well tolerated with outcomes comparable to chemoradiation for locally advanced pancreatic cancer (LAPC). Recent trials have reported improved survival with multiagent chemotherapy (MA-CTX) alone. This prospective trial explored whether SBRT could be safely delivered after MA-CTX. Herein, we report the long-term outcomes of adding SBRT after MA-CTX in LAPC patients and evaluate whether genetic profiles of specimens obtained before SBRT influence outcomes.

METHODS AND MATERIALS

This prospective nonrandomized controlled phase 2 trial enrolled 44 LAPC and 4 locally recurrent patients after multidisciplinary evaluation between 2012 and 2015 at a high-volume pancreatic cancer center. For induction CTX, most received modified FOLFIRINOX (mFFX), or gemcitabine and nab-paclitaxel (GnP) followed by 5-fraction SBRT for all. During fiducial placement, biopsies were obtained with DNA extracted for targeted sequencing using the Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets platform.

RESULTS

Median induction CTX duration was ≥4 months, and 31 patients received mFFX (65%). Among 44 LAPC patients, 17 (39%) were surgically explored, and 12 of 16 (75%) achieved a R0 resection. Median overall survival (mOS) was 20.2 and 14.6 months from diagnosis and SBRT, respectively. One- and 2-year OS from SBRT was 58% and 28%. The mOS after resection was 28.6 and 22.4 months from diagnosis and SBRT, respectively. Median local progression-free survival was 23.9 and 15.8 months from diagnosis and SBRT, respectively. The mOS for pre-SBRT CA 19-9 ≤180 U/mL versus >180 was 23.1 and 11.3 months, respectively (hazard ratio, 0.53; P = .04). Only 1 patient (2.1%) had late grade ≥2 gastrointestinal toxic effects attributable to SBRT. Despite significant pretreatment with chemotherapy, 88% of tumor specimens were effectively sequenced; survival outcomes were not significantly associated with specific mutational patterns. Quality of life was prospectively collected pre- and post-SBRT with the EORTC QLQ-C30 and PAN26 questionnaires showing no significant change.

CONCLUSIONS

SBRT was safely administered with MA-CTX with minimal toxicity. A high proportion of LAPC patients underwent R0 resection with favorable survival outcomes.

A safety study of intraoperative radiation therapy following stereotactic body radiation therapy and multi-agent chemotherapy in the treatment of localized pancreatic adenocarcinoma: study protocol of a phase I trial

BACKGROUND

Localized pancreatic adenocarcinoma carries a poor prognosis even after aggressive therapy. Up to 40% of patients may develop locoregional disease as the first site of failure. As such, there may be a role for intensification of local therapy such as radiation therapy. Radiation dose escalation for pancreatic cancer is limited by proximity of the tumor to the duodenum. However, the duodenum is removed during Whipple procedure, allowing the opportunity to dose escalate with intraoperative radiation therapy (IORT). Although prior studies have shown potential benefit of IORT in pancreatic cancer, these studies did not utilize ablative doses (biologically effective dose [BED10] > 100 Gy). Furthermore, the optimal radiation target volume in this setting is unclear. There has been increased interest in a "Triangle Volume" (TV), bordered by the celiac axis, superior mesenteric artery, common hepatic artery, portal vein, and superior mesenteric vein. Dissection of this area, has been advocated for by surgeons from Heidelberg as it contains extra-pancreatic perineural and lymphatic tracts, which may harbor microscopic disease at risk of mediating local failure. Interestingly, a recent analysis from our institution indicated that nearly all local failures occur in the TV. Therefore, the purpose of this protocol is to evaluate the safety of delivering an ablative radiation dose to the TV with IORT following neoadjuvant chemotherapy and stereotactic body radiation therapy (SBRT).

METHODS

Patients with non-metastatic pancreatic adenocarcinoma centered in the head or neck of the pancreas will be enrolled. Following treatment with multi-agent neoadjuvant chemotherapy, patients will undergo SBRT (40 Gy/5 fractions) followed by IORT (15 Gy/1 fraction) to the TV during the Whipple procedure. The primary objective is acute (< 90 days) toxicity after IORT measured by Clavien-Dindo classification. Secondary objectives include late (> 90 days) toxicity after IORT measured by Clavien-Dindo classification, overall survival, local progression-free survival, distant metastasis-free survival, and progression-free survival.

DISCUSSION

If the results show that delivering an ablative radiation dose to the TV with IORT after neoadjuvant chemotherapy and SBRT is safe and feasible, it warrants further investigation in a phase II trial to evaluate efficacy of this approach. Trial Registration This study was registered at ClinicalTrials.gov on 12/2/2021 (NCT05141513). https://clinicaltrials.gov/ct2/show/NCT05141513.

Advances and Remaining Challenges in the Treatment for Borderline Resectable and Locally Advanced Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest malignancies in the United States. Improvements in imaging have permitted the categorization of patients according to radiologic involvement of surrounding vasculature, i.e., upfront resectable, borderline resectable, and locally advanced disease, and this, in turn, has influenced the sequence of chemotherapy, surgery, and radiation therapy. Though surgical resection remains the only curative treatment option, recent studies have shown improved overall survival with neoadjuvant chemotherapy, especially among patients with borderline resectable/locally advanced disease. The role of radiologic imaging after neoadjuvant therapy and the potential benefit of adjuvant therapy for borderline resectable and locally advanced disease remain areas of ongoing investigation. The advances made in the treatment of patients with borderline resectable/locally advanced disease are promising, yet disparities in access to cancer care persist. This review highlights the significant advances that have been made in the treatment of borderline resectable and locally advanced PDAC, while also calling attention to the remaining challenges.

Neoadjuvant Stereotactic Body Radiotherapy After Upfront Chemotherapy Improves Pathologic Outcomes Compared With Chemotherapy Alone for Patients With Borderline Resectable or Locally Advanced Pancreatic Adenocarcinoma Without Increasing Perioperative Toxicity

BACKGROUND

Patients with borderline resectable pancreatic cancer (BRPC) or locally advanced pancreatic cancer (LAPC) are at high risk of margin-positive resection. Neoadjuvant stereotactic body radiation therapy (SBRT) may help sterilize margins, but its additive benefit beyond neoadjuvant chemotherapy (nCT) is unclear. The authors report long-term outcomes for BRPC/LAPC patients explored after treatment with either nCT alone or nCT followed by five-fraction SBRT (nCT-SBRT).

METHODS

Patients with BRPC or LAPC from 2011 to 2016 who underwent resection after nCT alone or nCT-SBRT were retrospectively reviewed. Baseline characteristics were compared, and the propensity score with inverse probability weighting (IPW) was used to compare pathologic/survival outcomes.

RESULTS

Of 198 patients, 76 received nCT, and 122 received nCT-SBRT. The nCT-SBRT cohort had a higher proportion of LAPC (53% vs 22%; p < 0.001). The duration of nCT was longer for nCT-SBRT (4.6 vs 2.9 months; p = 0.03), but adjuvant chemotherapy was less frequently administered (53% vs 67.1%; p < 0.001). Adjuvant radiation was administered to 30% of the nCT patients. The nCT-SBRT regimen more frequently achieved negative margins (92% vs 70%; p < 0.001), negative nodes (59% vs 42%; p < 0.001), and pathologic complete response (7% vs 0%; p = 0.02). In the multivariate analysis, nCT-SBRT remained associated with R0 resection (p < 0.001). The nCT-SBRT cohort experienced no significant difference in median overall survival (OS) (22.1 vs 24.5 months), local progression-free survival (LPFS) (13.5 vs. 15.4 months), or distant metastasis-free survival (DMFS) (11.7 vs 16.3 months) after surgery. After SBRT, 1-year OS was 77.0% and 2-year OS was 50.4%. Perioperative Claven-Dindo grade 3 or greater morbidity did not differ significantly between the nCT and nCT-SBRT cohorts (p = 0.81).

CONCLUSIONS

Despite having more advanced disease, the nCT-SBRT cohort was still more likely to undergo an R0 resection and experienced similar survival outcomes compared with the nCT alone cohort.

High local failure rates despite high margin-negative resection rates in a cohort of borderline resectable and locally advanced pancreatic cancer patients treated with stereotactic body radiation therapy following multi-agent chemotherapy

BACKGROUND

Stereotactic body radiation therapy (SBRT) for patients with borderline resectable and locally advanced pancreatic adenocarcinoma (BRPC/LAPC) remains controversial. Herein, we report on surgical, pathologic, and survival outcomes in BRPC/LAPC patients treated at a high-volume institution with induction chemotherapy (CTX) followed by 5-fraction SBRT.

METHODS

BRPC/LAPC patients treated between 2016 and 2019 were retrospectively reviewed. Surgical and pathological outcomes were descriptively characterized. Overall survival (OS) and progression-free survival (PFS) were analyzed using Cox proportional hazard regression. Locoregional failure and distant failure were analyzed with Fine-Gray competing risk model.

RESULTS

Of 155 patients, 91 (59%) had LAPC and 64 (41%) had BRPC. Almost all were treated with induction multi-agent CTX with either FOLFIRINOX (75%) or gemcitabine and nab-paclitaxel (24%) for a median duration of 4.0 months (1-18 months). All received SBRT to a median dose of 33 Gy. Among 64 BRPC patients, 50 (78%) underwent resection, of whom 48 (96%) achieved margin-negative (R0) resection. Among 91 LAPC patients, 57 (63%) underwent resection, of whom 50 (88%) achieved R0 resection. Despite the high R0 rate, 33% of patients experienced locoregional failure, which was a component of 44% of all failures. After SBRT, median OS and PFS were 18.7 and 7.7 months, respectively. After SBRT, 1- and 2-year OS probabilities were 70% and 45%, whereas, from diagnosis, they were 93% and 51%.

CONCLUSIONS

Although a high proportion of BRPC/LAPC patients treated with induction multi-agent CTX followed by SBRT successfully achieved R0 resection, locoregional failure remained common, highlighting the need to continue to optimize radiation delivery in this context.

Ablative Radiotherapy (ART) for Locally Advanced Pancreatic Cancer (LAPC): Toward a New Paradigm?

Locally advanced pancreatic cancer (LAPC) represents a major urgency in oncology. Due to the massive involvement of the peripancreatic vessels, a curative-intent surgery is generally precluded. Historically, LAPC has been an indication for palliative systemic therapy. In recent years, with the introduction of intensive multi-agent chemotherapy regimens and aggressive surgical approaches, the survival of LAPC patients has significantly improved. In this complex and rapidly evolving scenario, the role of radiotherapy is still debated. The use of standard-dose conventional fractionated radiotherapy in LAPC has led to unsatisfactory oncological outcomes. However, technological advances in radiation therapy over recent years have definitively changed this paradigm. The use of ablative doses of radiotherapy, in association with image-guidance, respiratory organ-motion management, and adaptive protocols, has led to unprecedented results in terms of local control and survival. In this overview, principles, clinical applications, and current pitfalls of ablative radiotherapy (ART) as an emerging treatment option for LAPC are discussed.

Intraoperative radiation therapy for early stage breast cancer

Background and objective

We report our experiences with Intraoperative radiation therapy (IORT) among breast cancer (BC) patients in our region.

Methods

All patients who received radical IORT from April 2014 on to March 2020 were included in the study. Patient selection criteria included: Age equal or older than 45 years old; All cases of invasive carcinomas (in cases of lobular carcinomas only with MRI and confirmation); Patients who were 45–50 years old with a tumor size of 0–2 cm, 50–55 years old with a tumor size of < 2.5 cm, and those who were ≥ 55 years old with a tumor size of < 3 cm; Invasive tumors only with a negative margin; Negative nodal status (exception in patients with micrometastasis); A positive estrogen receptor status. Primary endpoints included death and recurrence which were assessed using the Kaplan–Meier method.

Results

Overall, 252 patients entered the study. Mean (SD) age of patients was 56.43 ± 7.79 years. In total, 32.9% of patients had a family history of BC. Mean (SD) tumor size was 1.56 ± 0.55 cm. Mean (IQR) follow-up of patients was 36.3 ± 18.7 months. Overall, 8 patients (3.1%) experienced recurrence in follow-up visits (disease-free-survival of 96.1%), among which four (1.5%) were local recurrence, two (0.8%) were regional recurrence and two patients (0.8%) had metastasis. Median (IQR) time to recurrence was 46 (22, 53.7) months among the eight patient who had recurrence. Overall, one patient died due to metastasis in our series. Eleven patients (4.3%) with DCIS in our study received IORT. All these patients had free margins in histopathology examination and none experienced recurrence.

Conclusion

Inhere we reported our experience with the use of IORT in a region where facilities for IORT are limited using our modified criteria for patient selection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-021-01427-5.

Local Control and Survival After Induction Chemotherapy and Ablative Radiation Versus Resection for Pancreatic Ductal Adenocarcinoma With Vascular Involvement

OBJECTIVE

We sought to compare overall survival (OS) and disease control for patients with localized pancreatic ductal adenocarcinoma (PDAC) treated with ablative dose radiotherapy (A-RT) versus resection.

SUMMARY BACKGROUND DATA

Locoregional treatment for PDAC includes resection when possible or palliative RT. A-RT may offer durable tumor control and encouraging survival.

METHODS

This was a single-institution retrospective analysis of patients with PDAC treated with induction chemotherapy followed by A-RT [≥98 Gy biologically effective dose (BED) using 15-25 fractions in 3-4.5 Gy/fraction] or pancreatectomy.

RESULTS

One hundred and four patients received A-RT (49.8%) and 105 (50.2%) underwent resection. Patients receiving A-RT had larger median tumor size after induction chemotherapy [3.2 cm (undetectable-10.9) vs 2.6 cm (undetectable-10.7), P < 0.001], and were more likely to have celiac or hepatic artery encasement (48.1% vs 11.4%, P <0.001), or superior mesenteric artery encasement (43.3% vs 9.5%, P < 0.001); however, there was no difference in the degree of SMV/PV involvement (P = 0.123). There was no difference in locoregional recurrence/progression at 18-months between A-RT and resection; cumulative incidence was 16% [(95% confidence interval (CI) 10%-24%] versus 21% (95% CI 14%-30%), respectively (P= 0.252). However, patients receiving A-RT had a 19% higher 18-month cumulative incidence of distant recurrence/progression [58% (95% CI 48%-67%) vs 30% (95% CI 30%-49%), P= 0.004]. Median OS from completion of chemotherapy was 20.1 months for A-RT patients (95% CI 16.4-23.1 months) versus 32.9 months (95% CI 29.7-42.3 months) for resected patients (P < 0.001).

CONCLUSION

Ablative radiation is a promising new treatment option for PDAC, offering locoregional disease control similar to that associated with resection and encouraging survival.

Revision of Pancreatic Neck Margins Based on Intraoperative Frozen Section Analysis Is Associated With Improved Survival in Patients Undergoing Pancreatectomy for Ductal Adenocarcinoma

OBJECTIVE

To test the hypothesis that complete, tumor-free resection at the pancreatic neck, achieved either en-bloc or non-en-bloc (ie, revision based on intraoperative frozen section [FS] analysis), is associated with improved survival as compared with incomplete resection (IR) in pancreatic ductal adenocarcinoma.

SUMMARY BACKGROUND DATA

Given the likely systemic nature of pancreatic ductal adenocarcinoma, the oncologic benefit of achieving a histologically complete local resection, particularly through revision of a positive intraoperative FS at the pancreatic neck, remains controversial.

METHODS

Clinicopathologic and treatment data were reviewed for 986 consecutive patients with ductal adenocarcinoma at the head, neck, or uncinate process of the pancreas who underwent open pancreatectomy as well as intraoperative FS analysis between 1998 and 2012 at Massachusetts General Hospital and between 1998 and 2013 at the University of Verona. Overall survival (OS) and perioperative morbidity and mortality were compared across 3 groups: complete resection achieved en-bloc (CR-EB), complete resection achieved non-en-bloc (CR-NEB), and IR.

RESULTS

The CR-EB cohort comprised 749 (76%) patients, CR-NEB 159 patients (16%), and IR 78 patients (8%). Other than a higher incidence of vascular resection among CR-NEB and IR patients, no demographic, pathologic (eg, tumor grade, lymph node positivity, superior mesenteric artery involvement), or treatment factors (eg, neoadjuvant and adjuvant therapy use) differed between the groups. Median OS was significantly higher in patients with CR-EB (28 mo, P = 0.01) and CR-NEB resections (24 mo, P = 0.02) as compared with patients with IR resections (19 mo). After adjusting for clinicopathologic and treatment characteristics, CR-EB and CR-NEB margin status were found to be independent predictors of improved OS (relative to IR, CR-EB hazard ratio [HR] 0.65, 95% confidence interval [CI] 0.49-0.86; CR-NEB HR 0.69, 95% CI 0.50-0.96). There were no intergroup differences in perioperative morbidity and mortality, including rates of pancreatic fistula.

CONCLUSIONS

For patients with ductal adenocarcinoma at the head, neck, or uncinate process of the pancreas undergoing pancreatectomy, complete tumor extirpation via either en-bloc or non-en-bloc complete resection based on FS analysis is associated with improved OS, without an associated increased perioperative morbidity or mortality.

Radiotherapy for Resectable and Borderline Resectable Pancreas Cancer: When and Why?

The role of (chemo) radiation in the perioperative management of patients with resectable and borderline resectable pancreatic ductal adenocarcinoma is controversial. Herein, we review and interpret existing data relating to the ability of (chemo) radiation to "downstage" pancreatic tumors, delay recurrence, and prolong patients' survival. In sum, the evidence suggests that while neoadjuvant (chemo) radiation may impact pathologic metrics favorably, it rarely converts anatomically unresectable tumors to resectable ones. And while data do support the ability of (chemo)radiation to delay cancer progression, its ability to prolong longevity has not been confirmed. It is possible that (chemo)radiation is effective in prolonging the survival of select patients, but to date, this cohort remains undefined due to heterogeneity in both the populations studied and the regimens used to treat them. Based on our interpretation of existing data, we currently administer neoadjuvant and adjuvant (chemo)radiation selectively to patients with localized pancreatic cancer who we consider at highest risk for local progression. We may also use it as an alternative to pancreatectomy in patients who are poor candidates for surgery. Ultimately, the role of (chemo)radiation in these settings is evolving. Better studies of patients most likely to benefit from its local effects are necessary to clearly define its place within the perioperative treatment algorithms used for patients with localized pancreatic cancer.

Intraoperative Radiation Mitigates the Effect of Microscopically Positive Tumor Margins on Survival Among Pancreatic Adenocarcinoma Patients Treated with Neoadjuvant FOLFIRINOX and Chemoradiation

BACKGROUND

Microscopically positive margins (R1) negatively impact survival in pancreatic ductal adenocarcinoma (PDAC). For patients with close/positive margins, intraoperative radiotherapy (IORT) can improve local control. The prognostic impact of an R1 resection in patients who receive total neoadjuvant therapy (TNT; FOLFIRINOX with chemoradiation) and IORT is unknown.

METHODS

Clinicopathologic data were retrospectively collected for borderline/locally advanced (BR/LA) PDAC patients who received TNT and underwent resection between 2011 and 2019. Disease-free (DFS) and overall survival (OS) measured from time of diagnosis were compared between groups.

RESULTS

Two hundred one patients received TNT and were resected, with a median DFS and OS of 24 months and 47 months, respectively. Eighty-eight patients (44%) received IORT; of these, 69 (78%) underwent an R0 and 19 (22%) an R1 resection. There was no significant difference in clinicopathologic factors between the IORT and no-IORT groups, except for resectability status (LA: IORT 69%, no-IORT 53%, p = 0.021) and surgeons' concern for a positive/close margin. R1 resection was associated with worse DFS and OS in the no-IORT population. However, among patients who received IORT, there was no difference in DFS (R0: 29 months, IQR 14-47 vs R1: 20 months, IQR 15-28; p = 0.114) or OS (R0: 48 months, IQR 25-not reached vs R1: 37 months, IQR 30-47; p = 0.307) between patients who underwent R0 vs R1 resection. In multivariate analysis, within the IORT group, R1 resection was not associated with DFS or OS.

CONCLUSION

IORT may mitigate the adverse effect of an R1 resection on DFS and OS in BR/LA PDAC patients receiving TNT.

First report on the feasibility of a permanently implantable uni-directional planar low dose rate brachytherapy sheet for patients with resectable or borderline resectable pancreatic cancer

BACKGROUND

Margin negative resection in pancreatic cancer remains the only curative option but is challenging, especially with the retroperitoneal margin. Intraoperative radiation therapy (IORT) can improve rates of local control but requires specially designed facilities and equipment. This retrospective review describes initial results of a novel implantable mesh of uni-directional low dose rate (LDR) Pd-103 sources (sheet) used to deliver a focal margin-directed high-dose boost in patients with concern for close or positive margins.

METHODS

Eleven consecutive patients from a single institution with resectable or borderline resectable pancreatic cancer with concern for positive margins were selected for sheet placement and retrospectively reviewed. Procedural outcomes, including the time to implant the device and complications, and clinical outcomes, including survival and patterns of failure, are reported. A dosimetric comparison of the LDR sheet with hypothetical stereotactic body radiotherapy (SBRT) boost is reported.

RESULTS

One patient had a resectable disease, and 10 patients had a borderline resectable disease and underwent neoadjuvant treatment. Sheet placement added 15 min to procedural time with no procedural or sheet-related complications. At a median follow up of 13 months, 64% (n = 7) of patients are alive and 55% (n = 6) are disease-free. Compared to a hypothetical SBRT boost, the LDR sheet delivered a negligible dose to kidneys, liver, and spinal cord with a 50% reduction in max dose to the small bowel.

CONCLUSION

This is the first report of the use of an implantable uni-directional LDR brachytherapy sheet in patients with resected pancreatic cancer with concern for margin clearance, with no associated toxicity and favorable clinical outcomes.

Margin-Positive Pancreatic Ductal Adenocarcinoma during Pancreaticoduodenectomy: Additional Resection Does Not Improve Survival

BACKGROUND

The impact of resecting positive margins during pancreaticoduodenectomy (PD) for pancreatic ductal adenocarcinoma (PDA) remains debated. Additionally, the survival benefit of resecting multiple positive margins is unknown.

METHODS

We identified patients with PDA who underwent PD from 2006 to 2015. Pancreatic neck, bile duct, and uncinate frozen section margins were assessed before and after resection of positive margins. Survival curves were compared with log-rank tests. Multivariable Cox regression assessed the effect of margin status on overall survival.

RESULTS

Of 501 patients identified, 17.3%, 5.3%, and 19.7% had an initially positive uncinate, bile duct, or neck margin, respectively. Among initially positive bile duct and neck margins, 77.8% and 67.0% were resected, respectively. Although median survival was decreased among patients with any positive margins (15.6 vs. 20.9 months; p = 0.006), it was similar among patients with positive bile duct or neck margins with or without R1 to R0 resection (17.0 vs. 15.6 months; p = 0.20). Median survival with and without positive uncinate margins was 13.8 vs. 19.7 months (p = 0.04). Uncinate margins were never resected. Resection of additional margins when the uncinate was concurrently positive was not associated with improved survival (p = 0.37). Patients with positive margins who received adjuvant therapy had improved survival, regardless of margin resection (p = 0.03). Adjuvant therapy was independently protective against death (hazard ratio 0.6, 95% CI 0.5-0.7).

CONCLUSIONS

Positive PD margins at any position are associated with reduced overall survival; however, resection of additional margins may not improve survival, particularly with concurrently positive uncinate margins. Adjuvant chemotherapy improves survival with positive margins, regardless of resection.

ESTRO IORT Task Force/ACROP recommendations for intraoperative radiation therapy in borderline-resected pancreatic cancer

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Radiation dose-escalation with intraoperative electron beam radiation therapy to the posterior resection margin and/or to residual disease is feasible with limited toxicity.

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Preoperative therapy prolongs the interval to surgery and IOERT, allowing an improved selection of patients who are candidates for local treatment intensification.

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Primary systemic therapy combined with chemoradiation allows to boost with IOERT in over 70% of patients with R0 surgical tumour beds.

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Median survival time ranges from 19 to 35 months in electron boosted patients.

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Overall survival at 5 years of over 30% is reported by contemporary expert IOERT institutions.

Radiation therapy (RT) is a valuable component of multimodal treatment for localized pancreatic cancer. Intraoperative radiation therapy (IORT) is a very precise RT modality to intensify the irradiation effect for cancer involving upper abdominal structures and organs, generally delivered with electrons (IOERT). Unresectable, borderline and resectable disease categories benefit from dose-escalated chemoradiation strategies in the context of active systemic therapy and potential radical surgery. Prolonged preoperative treatment may act as a filter for selecting patients with occult resistant metastatic disease. Encouraging survival rates have been documented in patients treated with preoperative chemoradiation followed by radical surgery and IOERT (>20 months median survival, >35% survival at 3 years). Intensive preoperative treatment, including induction chemotherapy followed by chemoradiation and an IOERT boost, appears to prolong long-term survival within the subset of patients who remain relapse-free for>2 years (>30 months median survival; >40% survival at 3 years). Improvement of local control through higher RT doses has an impact on the survival of patients with a lower tendency towards disease spread. IOERT is a well-accepted approach in the clinical scenario (maturity and reproducibility of results), and extremely accurate in terms of dose-deposition characteristics and normal tissue sparing. The technique can be adapted to systemic therapy and surgical progress. International guidelines (National Comprehensive Cancer Network or NCCN guidelines) currently recommend use of IOERT in cases of close surgical margins and residual disease. We hereby report the ESTRO/ACROP recommendations for performing IOERT in borderline-resectable pancreatic cancer.

Intraoperative Strahlentherapie – Indikationen und Optionen in der Viszeralchirurgie

Hintergrund

Die intraoperative Strahlentherapie (IORT) ermöglicht durch die chirurgische Exposition des Tumors und des Tumorbetts eine hohe Präzision, welche eine hohe Strahlendosis im Bereich des Tumors zulässt und gleichzeitig gesundes Gewebe als den dosislimitierenden Faktor vor Strahlung schützt. Aus diesem Grund bietet die IORT besonders dann einen Vorteil, wenn die lokale Tumorkontrolle das Langzeitüberleben entscheidend beeinflusst und Funktionserhalt ermöglicht.

Ziel der Arbeit

Die in dieser Übersichtsarbeit aufgearbeiteten Erkenntnisse aus der Literaturrecherche erlauben einen evidenzbasierten Umgang hinsichtlich Indikationen und Therapieoptionen der IORT für intraabdominelle Tumoren.

Ergebnisse und Schlussfolgerung

Die Effektivität der IORT kann anhand der vorhandenen Evidenzlage nicht abschließend beurteilt werden, jedoch ist die IORT als Ergänzung der multimodalen Therapie bei (Rezidiv‑)Rektumkarzinomen und Sarkomen aktiv im klinischen Alltag etabliert. Magen- und Pankreaskarzinome stellen weitere Indikationen dar; ergänzende Studien sind jedoch notwendig, um die Rolle der IORT hier klar zu definieren. Ein wesentlicher Faktor, damit für Patienten mit primärem Karzinom und insbesondere für Patienten mit lokalem Rezidiv verbesserte lokale Rezidiv- und Überlebensraten erreicht werden können, scheint die Patientenselektion zu sein.

ESTRO IORT Task Force/ACROP recommendations for intraoperative radiation therapy in unresected pancreatic cancer

Radiation therapy (RT) is a valuable component of multimodal treatment for localized pancreatic cancer. Intraoperative radiation therapy (IORT) is a very precise sub-component of RT that can intensify the irradiation effect for cancer involving an anatomically well-defined volume, generally delivered with electrons (IOERT). Unresectable disease categories benefit from dose-escalated chemoradiation strategies in the context of active systemic therapy and potential radical surgery. Prolonged preoperative treatment may act as a filter for selecting patients with occult resistant metastatic disease. Long-term survivors were observed among unresected patients treated with external beam RT and an IOERT boost (OS 6% at 3 years; 3% >5 years). Improvement of local control through higher RT doses has an impact on the survival of patients with a lower tendency towards disease spread. IOERT is a well-accepted asset in the clinical scenario (maturity and reproducibility of results, albeit of low official level of evidence) and extremely accurate in terms of dose-deposit characteristics and normal tissue sparing. It is a technique that can be integrated with systemic therapy and surgical progress. International guidelines (National Comprehensive Cancer Network or NCCN guidelines) currently recommend the use of IOERT in cases of close surgical margins and residual disease. We report the ESTRO/ACROP recommendations for performing IOERT in unresected pancreatic cancer.

The role of intraoperative radiation therapy in resectable pancreatic cancer: a systematic review and meta-analysis

PURPOSE

Several studies investigating the role of intraoperative radiotherapy (IORT) in the treatment of resectable pancreatic cancer (PC) have been published; however, their results remain inconsistent. By conducting a systematic review and meta-analysis, this study aimed to compare clinical outcomes in patients with resectable PC who underwent surgery with or without IORT.

METHODS AND MATERIALS

The MEDLINE/PubMed, EMBASE, and Cochrane Library databases were searched to identify relevant studies published up to February 28, 2019. The main outcome measures included median survival time (MST), local recurrence (LR), postoperative complications, and operation-related mortality. Pooled effect estimates were obtained by performing a random-effects meta-analysis.

RESULTS

A total of 1095 studies were screened for inclusion, of which 15 studies with 834 patients were included in the meta-analysis. Overall, 401 patients underwent pancreatic resection with IORT and 433 underwent surgery without IORT. The pooled analysis revealed that IORT group experienced favorable overall survival (median survival rate [MSR], 1.20; 95% confidence interval [CI], 1.06-1.37, P = 0.005), compared with patients who did not receive IORT. Additionally, the pooled data showed a significantly reduced LR rate in the IORT group compared with that in the non-IORT group (relative risk [RR], 0.70; 95% CI, 0.51-0.97, P = 0.03). The incidences of postoperative complications (RR, 0.95; 95% CI, 0.73-1.23) and operation-related mortality (RR, 1.07; 95% CI, 0.44-2.63) were similar between the IORT and non-IORT groups.

CONCLUSION

IORT significantly improved locoregional control and overall survival in patients with resectable PC, without increasing postoperative complications and operation-related mortality rates.

Neoadjuvant Treatment in Pancreatic Cancer

Thanks to the development of modern chemotherapeutic regimens, survival after surgery for pancreatic ductal adenocarcinoma (PDAC) has improved and pancreatologists worldwide agree that the treatment of PDAC demands a multidisciplinary approach. Neoadjuvant treatment (NAT) plays a major role in the treatment of PDAC since only about 20% of patients are considered resectable at the time of diagnosis. Moreover, increasing data demonstrating the benefits of NAT for borderline resectable/locally advanced PDAC are driving a shift from up-front surgery to NAT in the multidisciplinary treatment of even resectable PDAC. Our understanding of the role of NAT in PDAC has evolved from tumor shrinkage to controlling potential micrometastases and selecting patients who may benefit from radical resection. The present review gives an overview on the current literature of NAT concepts for BR/LA PDAC and resectable PDAC.

The American Brachytherapy Society consensus statement on intraoperative radiation therapy

PURPOSE

Although radiation therapy has traditionally been delivered with external beam or brachytherapy, intraoperative radiation therapy (IORT) represents an alternative that may shorten the course of therapy, reduce toxicities, and improve patient satisfaction while potentially lowering the cost of care. At this time, there are limited evidence-based guidelines to assist clinicians with patient selection for IORT. As such, the American Brachytherapy Society presents a consensus statement on the use of IORT.

METHODS

Physicians and physicists with expertise in intraoperative radiation created a site-directed guideline for appropriate patient selection and utilization of IORT.

RESULTS

Several IORT techniques exist including radionuclide-based high-dose-rate, low-dose-rate, electron, and low-energy electronic. In breast cancer, IORT as monotherapy should only be used on prospective studies. IORT can be considered in the treatment of sarcomas with close/positive margins or recurrent sarcomas. IORT can be considered in conjunction with external beam radiotherapy for retroperitoneal sarcomas. IORT can be considered for colorectal malignancies with concern for positive margins and in the setting of recurrent gynecologic cancers. For thoracic, head and neck, and central nervous system malignancies, utilization of IORT should be evaluated on a case-by-case basis.

CONCLUSIONS

The present guidelines provide clinicians with a summary of current data regarding IORT by treatment site and guidelines for the appropriate patient selection and safe utilization of the technique. High-dose-rate, low-dose-rate brachytherapy methods are appropriate when IORT is to be delivered as are electron and low-energy based on the clinical scenario.

The DNA methylation profile of non-coding RNAs improves prognosis prediction for pancreatic adenocarcinoma

Background

Compelling lines of evidence indicate that DNA methylation of non-coding RNAs (ncRNAs) plays critical roles in various tumour progression. In addition, the differential methylation of ncRNAs can predict prognosis of patients. However, little is known about the clear relationship between DNA methylation profile of ncRNAs and the prognosis of pancreatic adenocarcinoma (PAC) patients.

Methods

The data of DNA methylation, RNA-seq, miRNA-seq and clinical features of PAC patients were collected from TCGA database. The DNA methylation profile was obtained using the Infinium HumanMethylation450 BeadChip array. LASSO regression was performed to construct two methylation-based classifiers. The risk score of methylation-based classifiers was calculated for each patient, and the accuracy of the classifiers in predicting overall survival (OS) was examined by ROC curve analysis. In addition, Cox regression models were utilized to assess whether clinical variables and the classifiers were independent prognostic factors for OS. The targets of miRNA and the genes co-expressed with lncRNA were identified with DIANA microT-CDS and the Multi-Experiment Matrix (MEM), respectively. Moreover, DAVID Bioinformatics Resources were applied to analyse the functional enrichment of these targets and co-expressed genes.

Results

A total of 4004 CpG sites of miRNA and 11,259 CpG sites of lncRNA were screened. Among these CpG sites, 8 CpG sites of miRNA and 7 CpG sites of lncRNA were found with regression coefficients. By multiplying the sum of methylation degrees of the selected CpGs with these coefficients, two methylation-based classifiers were constructed. The classifiers have shown good performance in predicting the survival rate of PAC patients at varying follow-up times. Interestingly, both of these two classifiers were predominant and independent factors for OS. Furthermore, functional enrichment analysis demonstrated that aberrantly methylated miRNAs and lncRNAs are related to calcium ion transmembrane transport and MAPK, Ras and calcium signalling pathways.

Conclusion

In the present study, we identified two methylation-based classifiers of ncRNA associated with OS in PAC patients through a comprehensive analysis of miRNA and lncRNA profiles. We are the first group to demonstrate a relationship between the aberrant DNA methylation of ncRNAs and the prognosis of PAC, and this relationship would contribute to individualized PAC therapy.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0828-8) contains supplementary material, which is available to authorized users.

Using adaptive magnetic resonance image-guided radiation therapy for treatment of inoperable pancreatic cancer

Background

Adaptive magnetic resonance imaging‐guided radiation therapy (MRgRT) can escalate dose to tumors while minimizing dose to normal tissue. We evaluated outcomes of inoperable pancreatic cancer patients treated using MRgRT with and without dose escalation.

Methods

We reviewed 44 patients with inoperable pancreatic cancer treated with MRgRT. Treatments included conventional fractionation, hypofractionation, and stereotactic body radiation therapy. Patients were stratified into high‐dose (biologically effective dose [BED₁₀] >70) and standard‐dose groups (BED₁₀ ≤70). Overall survival (OS), freedom from local failure (FFLF) and freedom from distant failure (FFDF) were evaluated using Kaplan‐Meier method. Cox regression was performed to identify predictors of OS. Acute gastrointestinal (GI) toxicity was assessed for 6 weeks after completion of RT.

Results

Median follow‐up was 17 months. High‐dose patients (n = 24, 55%) had statistically significant improvement in 2‐year OS (49% vs 30%, P = 0.03) and trended towards significance for 2‐year FFLF (77% vs 57%, P = 0.15) compared to standard‐dose patients (n = 20, 45%). FFDF at 18 months in high‐dose vs standard‐dose groups was 24% vs 48%, respectively (P = 0.92). High‐dose radiation (HR: 0.44; 95% confidence interval [CI]: 0.21‐0.94; P = 0.03) and duration of induction chemotherapy (HR: 0.84; 95% CI: 0.72‐0.98; P = 0.03) were significantly correlated with OS on univariate analysis but neither factor was independently predictive on multivariate analysis. Grade 3+ GI toxicity occurred in three patients in the standard‐dose group and did not occur in the high‐dose group.

Conclusions

Patients treated with dose‐escalated MRgRT demonstrated improved OS. Prospective evaluation of high‐dose RT regimens with standardized treatment parameters in inoperable pancreatic cancer patients is warranted.

Management of Borderline Resectable Pancreatic Cancer

With the rapid development of imaging modalities and surgical techniques, the clinical entity representing tumors that are intermediate between resectable and unresectable pancreatic adenocarcinoma has been identified has been termed "borderline resectable" (BR). These tumors are generally amenable for resection but portend an increased risk for positive margins after surgery and commonly necessitate vascular resection and reconstruction. Although there is a lack of consensus regarding the appropriate definition of what constitutes a BR pancreatic tumor, it has been demonstrated that this intermediate category carries a particular prognosis that is in between resectable and unresectable disease. In order to downstage the tumor and increase the probability of clear surgical margins, neoadjuvant therapy is being increasingly utilized and studied. There is a lack of high-level evidence to establish the optimal treatment regimen for BR tumors. When resection with negative margins is achieved after neoadjuvant therapy, the prognosis for BR tumors approaches and even exceeds that for resectable disease. This review presents the current definitions, different treatment approaches, and the clinical outcomes of BR pancreatic cancer.

Role and Future Directions of External Beam Radiotherapy for Primary Liver Cancer

The incidence of primary liver cancers continues to increase in the United States and worldwide. The majority of patients with primary liver cancer are not candidates for curative therapies such as surgical resection or orthotopic liver transplantation due to tumor size, vascular invasion, or underlying comorbidities. Therefore, while primary liver cancer is the sixth-most common cancer diagnosis worldwide, it represents the second leading cause of cancer-related deaths. Radiotherapy traditionally played a limited role in the treatment of primary liver cancer due to concerns over hepatic tolerance and the inability to deliver a tumoricidal dose of radiotherapy while still sparing normal hepatic parenchyma. However, the development of modern radiotherapy techniques has made liver-directed radiotherapy a safe and effective treatment option for both hepatocellular carcinoma and intrahepatic cholangiocarcinoma. An increasing body of literature has demonstrated the excellent local control and survival rates associated with liver-directed radiotherapy. These data include multiple radiotherapy techniques and modalities, including stereotactic body radiotherapy (SBRT), intensity modulated radiotherapy (IMRT), and charged particle therapy, including proton therapy. In this review, we discuss the development of liver-directed radiotherapy and evidence in support of its use, particularly in patients who are not candidates for resection or orthotopic liver transplantation. We also discuss future directions for its role in the management of primary liver cancers.

Intraoperative radiotherapy: review of techniques and results

Intraoperative radiotherapy (IORT) is a technique that involves precise delivery of a large dose of ionising radiation to the tumour or tumour bed during surgery. Direct visualisation of the tumour bed and ability to space out the normal tissues from the tumour bed allows maximisation of the dose to the tumour while minimising the dose to normal tissues. This results in an improved therapeutic ratio with IORT. Although it was introduced in the 1960s, it has seen a resurgence of popularity with the introduction of self-shielding mobile linear accelerators and low-kV IORT devices, which by eliminating the logistical issues of transport of the patient during surgery for radiotherapy or building a shielded operating room, has enabled its wider use in the community.

Electrons, low-kV X-rays and HDR brachytherapy are all different methods of IORT in current clinical use. Each method has its own unique set of advantages and disadvantages, its own set of indications where one may be better suited than the other, and each requires a specific kind of expertise.

IORT has demonstrated its efficacy in a wide variety of intra-abdominal tumours, recurrent colorectal cancers, recurrent gynaecological cancers, and soft-tissue tumours. Recently, it has emerged as an attractive treatment option for selected, early-stage breast cancer, owing to the ability to complete the entire course of radiotherapy during surgery. IORT has been used in a multitude of roles across these sites, for dose escalation (retroperitoneal sarcoma), EBRT dose de-escalation (paediatric tumours), as sole radiation modality (early breast cancers) and as a re-irradiation modality (recurrent rectal and gynaecological cancers).

This article aims to provide a review of the rationale, techniques, and outcomes for IORT across different sites relevant to current clinical practice.