The role of intraoperative radiotherapy in pancreatic cancer

Intraoperative radiation therapy induces immune response activity after pancreatic surgery

Background

Pancreatic cancer has highly aggressive features, such as local recurrence that leads to significantly high morbidity and mortality and recurrence after successful tumour resection. Intraoperative radiation therapy (IORT), which delivers targeted radiation to a tumour bed, is known to reduce local recurrence by directly killing tumour cells and modifying the tumour microenvironment.

Methods

Among 30 patients diagnosed with pancreatic cancer, 17 patients received IORT immediately after surgical resection. We investigated changes in the immune response induced by IORT by analysing the peritoneal fluid (PF) and blood of patients with and without IORT treatment after pancreatic cancer surgery. Further, we treated three pancreatic cell lines with PF to observe proliferation and activity changes.

Results

Levels of cytokines involved in the PI3K/SMAD pathway were increased in the PF of IORT-treated patients. Moreover, IORT-treated PF inhibited the growth, migration, and invasiveness of pancreatic cancer cells. Changes in lymphocyte populations in the blood of IORT-treated patients indicated an increased immune response.

Conclusions

Based on the characterisation and quantification of immune cells in the blood and cytokine levels in the PF, we conclude that IORT induced an anti-tumour effect by activating the immune response, which may prevent pancreatic cancer recurrence.

Clinical trial registration

NCT03273374.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08807-3.

Intraoperative radiotherapy vs concurrent chemoradiotherapy in the treatment of patients with locally advanced pancreatic cancer

PURPOSE

The purpose of the multi-institutional retrospective study was to evaluate whether intraoperative radiotherapy (IORT) has advantages in the treatment of patients with locally advanced pancreatic cancer (LAPC) compared with concurrent chemoradiotherapy (CCRT).

PATIENTS AND METHODS

A total of 103 patients with LAPC whom was treated with IORT (Arm A; n = 50) or CCRT (Arm B; n = 53) from 2015.6 to 2016.7 were retrospectively identified. Data on feasibility, toxicity, and overall survival (OS) were evaluated.

RESULTS

Most factors of the two cohorts were similar. The severe adverse events (grade 3 and 4) patients in Arm B were higher than patients in Arm A (34% vs 0%). Disease progression was noted in 38 patients (76%) in Arm A and 37 patients (69.8%) in Arm B. The median survival of patients in Arm A and B were 15.3 months (95% CI, 13.0-17.6 months) and 13.8 months (95% CI, 11.0-16.6 months), respectively. The 1-year survival rate were 66.3% in Arm A (95% CI, 52.3%-80.2%) and 60.9% in Arm B (95% CI, 46.4%-75.4%). There was no significant difference in OS between patients treated with IORT and with CCRT (p = 0.458).

CONCLUSION

Our results demonstrated that patients with LAPC treated with IORT showed fewer adverse events, less treatment time, and high feasibility compared to CCRT. Although, IORT has no advantages in survival and tumor control compared with CCRT.

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.

Peripheral dose around a mobile linac for intraoperative radiotherapy: radiation protection aspects

The aim of this work is to analyse the scattered radiation produced by the mobile accelerator Mobetron 1000. To do so, detailed Monte Carlo simulations using two different codes, Penelope2008 and Geant4, were performed. Measurements were also done. To quantify the attenuation due to the internal structures, present in the accelerator head, on the scattered radiation produced, some of the main structural shielding in the Mobetron 1000 has been incorporated into the geometry simulation. Results are compared with measurements. Some discrepancies between the calculated and measured dose values were found. These differences can be traced back to the importance of the radiation component due to low energy scattered electrons. This encouraged us to perform additional calculations to separate the role played by this component. Ambient dose equivalent, H*(10), outside of the operating room (OR) has been evaluated using Geant4. H*(10) has been measured inside and outside the OR, being its values compatible with those reported in the literature once the low energy electron component is removed. With respect to the role played by neutrons, estimations of neutron H*(10) using Geant4 together with H*(10) measurements has been performed for the case of the 12 MeV electron beam. The values obtained agree with the experimental values existing in the literature, being much smaller than those registered in conventional accelerators. This study is a useful tool for the clinical user to investigate the radiation protection issues arising with the use of these accelerators in ORs without structural shielding. These results will also enable to better fix the maximum number of treatments that could be performed while insuring adequate radiological protection of workers and public in the hospital.

Intraoperative radiation therapy (IORT) in pancreatic cancer

Despite the important improvements made in the fields of surgery, chemotherapy and radiation therapy, pancreatic cancer remains one of the most lethal malignancies. Improved outcomes with novel chemotherapy regimes led again to increased attention on the role of localized radiotherapy, since local tumor progression causes significant morbidity and mortality in patients. Even after resection local failure rates are as high as 50-80%. The immediate proximity to critical structures (bone marrow, spinal cord, kidneys, liver, and intestine) limits the dose of radiation that can be administered to the tumor bed with conventional external beam radiation therapy (EBRT). The intraoperative radiotherapy (IORT) appears to be an ideal therapeutic strategy for this disease, having the advantage of enabling the delivery of high doses of radiation to areas that are at risk for microscopic disease, saving critical organs and reducing the possibility of inducing radiotoxicity. This technique allows a theoretical increase in the radiation therapeutic index to tumor compared to the adjacent organs at risk (OAR). The aim of this review is to update and comment on IORT in the multidisciplinary management of pancreatic cancer.

Treatment Approaches to Locally Advanced Pancreatic Adenocarcinoma

This article focuses on the management of locally advanced pancreatic cancer, which should be treated as a distinct entity separate from metastatic disease and borderline resectable disease. Although the role, timing, and sequencing of radiation relative to systemic therapy in this disease are controversial, an emerging treatment paradigm involves induction chemotherapy, followed by consolidative chemoradiation in patients who do not progress. In addition, new chemotherapy regimens as well as novel radiosensitizers have shown promise and need to be tested further in the locally advanced setting. Advances in radiotherapy have enabled stereotactic body radiotherapy and should continue to be prospectively evaluated.

Management options in locally advanced pancreatic cancer

Pancreatic ductal adenocarcinoma is a highly lethal cancer that is rarely curable at the time of presentation. Unfortunately, most patients are diagnosed with either metastatic or locally advanced disease, which is not amenable to surgery owing to the high likelihood of incomplete resection. Given the generally poor prognosis with propensity for metastatic failure greater than that for local failure, treatment options are variable, and include chemotherapy, radiotherapy, targeted therapies, and combinations thereof. This review summarizes the current evidence for definitive management of locally advanced pancreatic adenocarcinoma, as well as the role of palliative therapies. Future directions, including the development of predictive biomarkers and novel systemic agents, are also discussed.

Partial–breast irradiation: towards a replacement for whole–breast irradiation?

Largely thanks to all of the investigators and patients who have participated in randomized breast-conservation trials, many women facing a diagnosis of breast cancer today can conserve their breast with the help of adjuvant radiation therapy. A standard course of radiation consists of 5-7 weeks of daily radiation treatments delivered to the whole breast. The success of this treatment has led investigators to attempt to determine whether the same control can be achieved while decreasing the volume of breast tissue irradiated, thus allowing treatment to be delivered in a shorter period of time. This approach could alleviate time and logistical problems faced by patients during their course of treatment as well as improving overall cost-effectiveness. It can also allow complete avoidance of the adjacent heart and lung tissue in the radiation treatment portal. Partial-breast irradiation (the delivery of radiation to the resection cavity, plus a safety margin) delivered in just hours or days, is currently under investigation. Although relatively new, its use is growing rapidly and many institutional and cooperative group trials are quickly enlisting patients, while physicians are gaining experience in a variety of partial-breast irradiation techniques.

Radiation dose ≥54 Gy and CA 19-9 response are associated with improved survival for unresectable, non-metastatic pancreatic cancer treated with chemoradiation

BACKGROUND

Unresectable pancreatic cancer (UPC) has low survival. With improving staging techniques and systemic therapy, local control in patients without metastatic disease may have increasing importance. We investigated whether the radiation dose used in chemoradiation (CRT) as definitive treatment for UPC and the CA 19-9 response to therapy have an impact on overall survival (OS).

METHODS

From 1997-2009 46 patients were treated with CRT for non-metastatic UPC. Median prescribed RT dose was 54 Gy (range 50.4-59.4 Gy). All patients received concurrent chemotherapy (41: 5-fluorouracil, 5: other) and 24 received adjuvant chemotherapy.

RESULTS

41 patients were inoperable due to T4 disease and 5 patients with T3 disease were medically inoperable. Five patients did not complete CRT due to progressive disease or treatment-related toxicity (median RT dose 43.2 Gy). Overall, 42 patients were dead of disease at the time of last follow-up. The median and 12 month OS were 8.8 months and 35%, respectively. By univariate analysis, minimum CA 19-9 post-CRT <90 U/mL was favorably associated with OS (12.3 versus 8.8 months, p = 0.012). Radiotherapy dose ≥54 Gy trended towards improved OS (11.3 versus 6.8 months, p = 0.089). By multivariable analysis, a delivered RT dose of ≥54 Gy (HR 0.47, p = 0.028) and minimum CA 19-9 post-CRT of <90 U/mL (HR 0.35, p = 0.008) were associated with OS.

CONCLUSIONS

CRT as definitive treatment for UPC had low survival. However, our retrospective data suggest that patients treated to ≥54 Gy or observed to have a minimum post-CRT CA 19-9 <90 U/mL had improved likelihood of long-term survival.

Prognostic implications of intraoperative radiotherapy for unresectable pancreatic cancer

BACKGROUND/AIMS

To assess the prognostic effect of intraoperative radiotherapy (IORT) in unresectable pancreatic cancer.

METHODS

We reviewed 198 patients with unresectable pancreatic cancer, which was found during experimental laparotomy. Liver metastasis was observed in 70 patients, peritoneal metastasis in 44, liver and peritoneal metastasis in 23 and locally advanced tumor in 61. Treatment consisted of IORT with or without postoperative chemotherapy. Overall survival (OS) and prognostic factors were evaluated for each pattern of disease spread.

RESULTS

IORT was performed in 120 patients, and chemotherapy was administered in 80. Sixty patients did not receive either treatment. OS in the untreated group was significantly inferior to that for IORT alone and IORT plus gemcitabine (GEM)-based chemotherapy. IORT and GEM-based chemotherapy were identified as independent prognostic factors [hazard ratio (HR) = 0.51, p < 0.001; HR = 0.43, p < 0.001]. IORT was an independent prognostic determinant for patients with peritoneal metastasis (HR = 0.24, p = 0.011) but not for those with liver metastasis (HR = 0.78, p = 0.381).

CONCLUSION

IORT followed by GEM-based chemotherapy is the recommended treatment strategy in unresectable pancreatic cancer. and IAP.

The role of intraoperative radiotherapy in solid tumors

BACKGROUND

Combined multimodality therapy is becoming standard treatment for many solid tumors, but the role of intraoperative radiotherapy in the management of solid tumors remains uncertain. The aim is to review the indication, application, and outcomes of intraoperative radiotherapy in the management of nongynecological solid tumors.

METHODS

A literature search was performed using Medline, Embase, Ovid, and Cochrane database for studies between 1965 and 2008 assessing intraoperative radiotherapy, using the keywords "intraoperative radiotherapy," "colorectal cancer," "breast cancer," "gastric cancer," "pancreatic cancer," "soft tissue tumor," and "surgery." Only publications in English with available abstracts and regarding adult humans were included, and the evidence was critically evaluated.

RESULTS

Our search retrieved 864 publications. After exclusion of nonclinical papers, duplicated papers and exclusion of brachytherapy papers, 77 papers were suitable to assess the current role of intraoperative radiotherapy. The clinical application and evidence base of intraoperative radiotherapy for each cancer is presented.

CONCLUSIONS

Current studies in all common cancers show an additional benefit in local recurrence rates when intraoperative radiotherapy is included in the multimodal treatment. However, intraoperative radiotherapy may not improve overall survival and has significant morbidity depending on the site of the tumor. Intraoperative radiotherapy does have a role in the multidisciplinary management of solid tumors, but further studies are required to more precisely determine the extent of benefit.

Intraoperative radiation therapy using a mobile electron linear accelerator: field matching for large-field electron irradiation

Intraoperative radiation therapy (IORT) consists of delivering a large, single-fraction dose of radiation to a surgically exposed tumour or tumour bed at the time of surgery. With the availability of a mobile linear accelerator in the OR, IORT procedures have become more feasible for medical centres and more accessible to cancer patients. Often the area requiring irradiation is larger than what the treatment applicators will allow, and therefore, two or more adjoining fields are used. Unfortunately, the divergence and scattering of the electron beams may cause significant dose variations in the region of the field junction. Furthermore, because IORT treatments are delivered in a large single fraction, the effects of underdosing or overdosing could be more critical when compared to fractionated external beam therapy. Proper matching of the fields is therefore an important technical aspect of treatment delivery. We have studied the matching region using the largest flat applicator available for three different possibilities: abutting the fields, leaving a small gap or creating an overlap. Measurements were done using film dosimetry for the available energies of 4, 6, 9 and 12 MeV. Our results show the presence of clinically significant cold spots for the low-energy beams when the fields are either gapped or abutted, suggesting that the fields should be overlapped. No fields should be gapped. The results suggest that an optimal dose distribution may be obtained by overlapping the fields at 4 and 6 MeV and simply abutting the fields at 9 and 12 MeV. However, due to uncertainties in the placement of lead shields during treatment delivery, one may wish to consider overlapping the higher energy fields as well.

Intraoperative radiation therapy using mobile electron linear accelerators: report of AAPM Radiation Therapy Committee Task Group No. 72

Intraoperative radiation therapy (IORT) has been customarily performed either in a shielded operating suite located in the operating room (OR) or in a shielded treatment room located within the Department of Radiation Oncology. In both cases, this cancer treatment modality uses stationary linear accelerators. With the development of new technology, mobile linear accelerators have recently become available for IORT. Mobility offers flexibility in treatment location and is leading to a renewed interest in IORT. These mobile accelerator units, which can be transported any day of use to almost any location within a hospital setting, are assembled in a nondedicated environment and used to deliver IORT. Numerous aspects of the design of these new units differ from that of conventional linear accelerators. The scope of this Task Group (TG-72) will focus on items that particularly apply to mobile IORT electron systems. More specifically, the charges to this Task Group are to (i) identify the key differences between stationary and mobile electron linear accelerators used for IORT, (ii) describe and recommend the implementation of an IORT program within the OR environment, (iii) present and discuss radiation protection issues and consequences of working within a nondedicated radiotherapy environment, (iv) describe and recommend the acceptance and machine commissioning of items that are specific to mobile electron linear accelerators, and (v) design and recommend an efficient quality assurance program for mobile systems.

Benefits of early postoperative jejunal feeding in patients undergoing duodenohemipancreatectomy

AIM: To study whether early postoperative enteral nutrition reduces the incidence of complications and/or improves nutritional status following duodenohemipancreatectomy (DHP).

METHODS: We studied 39 patients who underwent DHP for a peri-ampullary mass. Twenty-three patients received total parental nutrition and then started to have an oral intake of nutrition between postoperative day (POD) 7 and 14 [late postoperative enteral nutrition (LPEN) group]. Sixteen patients started to have enteral feeding through a jejunostomy catheter the day after the operation [early postoperative enteral nutrition (EPEN) group]. The incidence of complications and laboratory data at the early postoperative stage were studied in comparison between LPEN and EPEN groups.

RESULTS: Serum levels of albumin and total protein in the EPEN group were significantly higher than those in the LPEN group. The loss of body mass index was significantly suppressed in the EPEN group as compared to the LPEN group. The lymphocyte count decreased immediately after the operation was restored significantly faster in the EPEN group than in the LPEN group. The EPEN group showed significantly fewer incidences of postoperative pancreatic fistulas, as well as a significantly shorter length of hospitalization than the LPEN group. There were no significant differences in the incidences of other postoperative complications between the two groups, such as delayed gastric emptying, surgical site infection, cholangitis, and small bowel obstruction.

CONCLUSION: EPEN is a safe and beneficial opportunity for patients who have undergone DHP for a peri-ampullary mass.

Neoadjuvant chemoradiation in patients with pancreatic adenocarcinoma

In spite of the high mortality in pancreatic cancer, significant progress is being made. This review discusses multimodality therapy for patients with pancreatic cancer. Surgical therapy currently offers the only potential monomodal cure for pancreatic adenocarcinoma. However, only 10-20% of patients present with tumors that are amenable to resection, and even after resection of localized cancers, long-term survival is rare. The addition of chemoradiation therapy significantly increases median survival. To achieve long-term success in treating this disease it is therefore increasingly important to identify effective neoadjuvant/adjuvant multimodality therapies. Preoperative chemoradiation for potentially resectable pancreatic cancer has the following advantages: (1) neoadjuvant treatment would eliminate the delay of adjuvant treatment due to postoperative complications; (2) neoadjuvant treatment could avoid unnecessary surgery for patients with metastatic disease evident on restaging after neoadjuvant therapy; (3) down-staging after neoadjuvant therapy may increase the likelihood of negative surgical margins; and (4) neoadjuvant treatment could prevent peritoneal tumor cell implantation and dissemination caused during surgery. This review systematically summarizes the current status, controversies, and prospects of neoadjuvant treatment of pancreatic cancer.

Randomized phase II--study evaluating EGFR targeting therapy with cetuximab in combination with radiotherapy and chemotherapy for patients with locally advanced pancreatic cancer--PARC: study protocol [ISRCTN56652283]

BACKGROUND

Pancreatic cancer is the fourth commonest cause of death from cancer in men and women. Advantages in surgical techniques, radiation therapy techniques, chemotherapeutic regimes, and different combined-modality approaches have yielded only a modest impact on the prognosis of patients with pancreatic cancer. Thus there is clearly a need for additional strategies. One approach involves using the identification of a number of molecular targets that may be responsible for the resistance of cancer cells to radiation or to other cytotoxic agents. As such, these molecular determinants may serve as targets for augmentation of the radiotherapy or chemotherapy response. Of these, the epidermal growth factor receptor (EGFR) has been a molecular target of considerable interest and investigation, and there has been a tremendous surge of interest in pursuing targeted therapy of cancers via inhibition of the EGFR.

METHODS/DESIGN

The PARC study is designed as an open, controlled, prospective, randomized phase II trial. Patients in study arm A will be treated with chemoradiation using intensity modulated radiation therapy (IMRT) combined with gemcitabine and simultaneous cetuximab infusions. After chemoradiation the patients receive gemcitabine infusions weekly over 4 weeks. Patients in study arm B will be treated with chemoradiation using intensity modulated radiation therapy (IMRT) combined with gemcitabine and simultaneous cetuximab infusions. After chemoradiation the patients receive gemcitabine weekly over 4 weeks and cetuximab infusions over 12 weeks. A total of 66 patients with locally advanced adenocarcinoma of the pancreas will be enrolled. An interim analysis for patient safety reasons will be done one year after start of recruitment. Evaluation of the primary endpoint will be performed two years after the last patient's enrollment.

DISCUSSION

The primary objective of this study is to evaluate the feasibility and the toxicity profile of trimodal therapy in pancreatic adenocarcinoma with chemoradiation therapy with gemcitabine and intensity modulated radiation therapy (IMRT) and EGFR-targeted therapy using cetuximab and to compare between two different methods of cetuximab treatment schedules (concomitant versus concomitant and sequential cetuximab treatment). Secondary objectives are to determine the role and the mechanism of cetuximab in patient's chemoradiation regimen, the response rate, the potential of this combined modality treatment to concert locally advanced lesions to potentially resectable lesions, the time to progression interval and the quality of life.

Intraoperative radiotherapy using a mobile electron LINAC: a retroperitoneal sarcoma case

The advent of mobile LINACs for use in intraoperative radiation therapy (IORT) promises to make IORT more accessible than before and easier to deliver to patients undergoing surgery. Although mobile IORT systems have been available since 1999, few treatment centers currently use them. Here, we present the case of a typical patient undergoing IORT for retroperitoneal sarcoma to show how easy these mobile systems are to use and how adaptable they are within the operating room (OR) environment. We also discuss the roles and coordination of multidisciplinary team members during IORT and the feasibility of using mobile LINACs for IORT.

PACS number(s):

Factors predicting recurrence after resection of pancreatic ductal carcinoma

OBJECTIVE

Pancreatic ductal carcinoma frequently recurs postoperatively, and we analyzed clinicopathological features of patients treated by surgical resection to find predictors of postoperative recurrence.

METHODS

A retrospective cohort study was performed that included 69 patients between 1985 and 2003. Clinicopathologic factors were evaluated for tumor recurrences by univariate and multivariate analyses.

RESULTS

Mean survival time and actuarial 5-year disease-specific survival were significantly lower in cases of hepatic metastasis (13 months, 0%) and in cases of peritoneal carcinomatosis (15 months, 6.8%) than in cases of local retroperitoneal recurrence (30 months, 21%). Univariate and logistic regression analyses showed undifferentiated adenocarcinoma to be independently associated with hepatic metastasis (odds ratio, 7.4; 95% confidence interval, 1.5-37.0) and invasion of the portal vein to be independently associated with peritoneal carcinomatosis (odds ratio, 4.0; 95% confidence interval, 1.2-12.8). Multivariate analysis showed undifferentiated adenocarcinoma, invasion of the anterior capsule, and invasion of the portal vein to be independent prognostic factors.

CONCLUSION

Undifferentiated adenocarcinoma and invasion of the portal vein are predictors of poor outcome and are related to hepatic metastasis and peritoneal carcinomatosis, respectively. Postoperative adjuvant chemotherapy, including intra-arterial chemotherapy, should be selected according to prediction of the patterns of recurrence.