Exocrine pancreatic function following intraoperative irradiation of the canine pancreas

Radioprotective effects of α2-adrenergic receptor agonist dexmedetomidine on X-ray irradiation-induced pancreatic islet cell damage

Comprehensive epidemiological analyses conducted in the last 30 years have revealed a link between radiation and DM. We aimed to determine the effects of dexmedetomidine pretreatment on radiation-induced pancreatic islet cell damage. Twenty-four rats were divided into three groups: group 1 (control group), group 2 (only X-ray irradiation group), and group 3 (X-ray irradiation + dexmedetomidine). We observed necrotic cells with vacuoles accompanying loss of cytoplasm in the islets of Langerhans, extensive edematous areas, and vascular congestions in group 2. In group 3, we observed a decrease in necrotic cells in the islets of Langerhans, and edematous areas and vascular congestion was also reduced. We determined a decrease in β-cells, α-cells, and D-cells in the islets of Langerhans in group 2 compared to the control group. In group 3, β-cells, α-cells, and D-cells were elevated compared to group 2. Ionizing radiation may induce DM. Dexmedetomidine appears to exert a radioprotective effect.

The usefulness of preoperative exocrine function evaluated by the 13C-trioctanoin breath test as a significant physiological predictor of pancreatic fistula after pancreaticoduodenectomy

Background

The association between pancreatic fistula (PF) after pancreaticoduodenectomy (PD) and preoperative exocrine function is yet to be elucidated. This study aimed to evaluate the association between the preoperative results of the ¹³C-trioctanoin breath test and the occurrence of PF, showing the clinical relevance of the breath test in predicting PF.

Method

A total of 80 patients who underwent ¹³C-trioctanoin breath tests prior to PD from 2006 to 2018 were included in this study. Univariate and multivariate analyses were conducted to reveal the preoperative predictors of PF, showing the association between ¹³C-trioctanoin absorption and PF incidence.

Results

Among 80 patients (age, 68.0 ± 11.9 years, 46 males and 34 females; 30 pancreatic ductal adenocarcinoma [PDAC]/50 non-PDAC patients), the incidence of PF was 12.5% (10/80). Logistic regression analysis results revealed that the frequency of PF increased significantly as the ¹³C-trioctanoin breath test value (Aa% dose/h) increased (odd’s ratio: 1.082, 95% confidence interval: 1.007–1.162, p = 0.032). Moreover, the optimal cutoff value of the preoperative fat absorption level to predict PF was 38.0 (sensitivity, 90%; specificity, 74%; area under the curve, 0.78; p = 0.005). Indeed, the incidence of PF was extremely higher in patients whose breath test value was greater than 38.0 (33%, 9/27) compared with that in patients with values less than 38.0 (1.8%, 1/53).

Conclusions

Favorable preoperative fat absorption evaluated using the ¹³C-trioctanoin breath test is a feasible and objective predictor of PF after PD.

Canine Cancer: Strategies in Experimental Therapeutics

Cancer is the most common cause of death in adult dogs. Many features of spontaneously developing tumors in pet dogs contribute to their potential utility as a human disease model. These include similar environmental exposures, similar clonal evolution as it applies to important factors such as immune avoidance, a favorable body size for imaging and serial biopsy, and a relatively contracted time course of disease progression, which makes evaluation of temporal endpoints such as progression free or overall survival feasible in a comparatively short time frame. These criteria have been leveraged to evaluate novel local therapies, demonstrate proof of tumor target inhibition or tumor localization, evaluate potential antimetastatic approaches, and assess the efficacy, safety and immune effects of a variety of immune-based therapeutics. Some of these canine proof of concept studies have been instrumental in informing subsequent human clinical trials. This review will cover key aspects of clinical trials in dogs with spontaneous neoplasia, with examples of how these studies have contributed to human cancer therapeutic development.

Predictive value of pancreatic dose-volume metrics on sarcopenia rate in gastric cancer patients treated with adjuvant chemoradiotherapy

OBJECTIVE

To evaluate the relationship of sarcopenia with the pancreatic dose-volume histogram (DVH) in gastric cancer patients treated with adjuvant chemoradiotherapy (CRT) after radical gastrectomy.

METHODS

A retrospective study was performed on the data in Zhongnan Hospital of Wuhan University from January 2008 to December 2016. Skeletal muscle index (SMI) was analyzed by cross-sectional areas of body composition at the level of third lumbar (L3) vertebrae, which was measured using single-slice computer tomograph (CT) prior to CRT, at 6 months and 12 months after CRT respectively. Logistic regression analysis was conducted to explore the potential clinical risk factors of sarcopenia in this patients cohort. Regarding the dosimetrics of pancreas, the sarcopenia rate was compared between the two groups divided according to the cut-off value determined by the receiver operating characteristic (ROC) curves.

RESULTS

One hundred and fifty-three gastric cancer patients were eligible in this study. The median postoperative follow-up was 36 (7-115) months. The mean dose of pancreas was 4399.7 ± 396.0 cGy. The incidence of sarcopenia prior to CRT, at 6 months and 12 months later were 29.4% (45/153), 27.3% (35/128) and 37.0% (37/100). Both sarcopenia at 6 months (HR = 2.038, 95%CI = 1.084-3.833, P = 0.027) and sarcopenia at 12 months (HR = 2.216, 95%CI = 1.007-4.873, P = 0.048) were the independent prognostic factor of gastric cancer patients. V46 remained to be the only independent risk factor of sarcopenia at 6 months (OR = 3.889, 95%CI = 1.099-13.764, P = 0.035) and 12 months (OR = 6.067, 95%CI = 1.687-21.821, P = 0.006) in multivariate logistic regression analysis. Among the dosimetric parameters used for ROC analysis, the V46 showed the highest area under the curve (AUC = 0.707). Here is the relationship between sarcopenia rate and the cut-off value for V46. Higher sarcopenia rate at 6 months was noted in 42.6% patients with V46 ≥ 57% compared with 9% of patients with V46 < 57% (P < 0.001). The sarcopneia rate at 12 months was 52% with V46 ≥ 57% and 25% with V46 < 57% (P = 0.010).

CONCLUSION

Gastric cancer with sarcopenia after adjuvant CRT had poorer survival. Higher dose and larger irradiated volume of pancreas correlated with higher risk of sarcopenia. Appropriated administration of pancreas dose-volume may be conducive to reduce the risk of sarcopenia and improve survival in gastric cancer patients treated with adjuvant CRT.

The Role of Intraoperative Therapy by Electron Beam and Combination of Adjuvant Chemotherapy and External Radiotherapy in Carcinoma of the Pancreas

Aims and background

In the treatment of pancreatic carcinomas, one modality is intraoperative radiotherapy (IORT). A study was carried out to assess the feasibility of IORT alone or in a multimodality approach with postoperative adjuvant chemotherapy and external radiotherapy and to compare local control and survival of patients. Another objective of this retrospective study was to verify prognostic factors in resected patients treated with IORT.

Methods

From January 1985 through September 1992, 54 adenocarcinomas of the pancreas (unresectable and resected patients) were treated with IORT by electron beam at the San Raffaele Hospital and then analyzed. Comparison was also carried out between IORT-treated resected patients and a non-randomized control group of resected patients treated without IORT in the same period.

Results

In unresectable patients treated by laparotomy bypass and IORT, overall median survival was 6 months and 8 months in non-metastatic patients. Relief of severe pain present in 14 patients was observed in 85% within 12 days of IORT. As regards resected patients, the most important finding was that significantly better local control resulted from IORT. In fact, overall, local relapses were 25% in the IORT group and 55.8% in the non-IORT group (control group); instead, survival of the IORT group was not significantly longer than that of the control group. From a statistical analysis of resected patients treated with IORT and performed on prognostic factors on the basis of available data, survival was significantly influenced by tumor pathologic grading and diameter; postoperative adjuvant therapy was not a significant prognosis factor.

Conclusions

IORT has a role in local control of unresectable pancreatic carcinomas and in control of resultant severe pain. In resected patients, IORT is effective in decreasing local recurrences but has little impact on survival. To obtain more satisfactory results, new and more effective adjuvant therapies and better abdominal prophylaxis should be tested.

Radiation-induced injury of the exocrine pancreas after chemoradiotherapy for gastric cancer

BACKGROUND AND PURPOSE

The pancreas is located almost entirely within the treatment area for radiotherapy of gastric cancer. The aim of this study was to analyze radiation-induced injury of the exocrine pancreas.

MATERIAL AND METHODS

The study included 127 gastric cancer patients, who underwent preoperative or postoperative chemoradiotherapy. A total dose of 45 Gy was given in 25 fractions. Concurrent chemotherapy was 5-fluorouracil-based. Lipase and α-amylase were assayed before, during and after treatment.

RESULTS

Lipase and α-amylase deficiencies were found in 48.2% and 19.7% of patients, respectively. In the univariant analysis, age and pretreatment α-amylase and lipase activities influenced on risk of injury of the exocrine pancreas (p<0.05). Younger patients (<65 years) had a lower risk of hypoamylasemia than older patients. The probability of insufficiency was lower than 0.2 for patients with pretreatment α-amylase and lipase activities above 50 U/L and 55 U/L, respectively. The multivariate analyses of the time to hypolipasemia showed that only pretreatment lipase activity was significant.

CONCLUSIONS

Gastric cancer patients have an increased risk of exocrine pancreatic insufficiency after chemoradiotherapy. Thus, the pancreas should be regarded as an OAR. Measuring lipase activity should be the standard for assessing radiation-induced pancreatic injury.

Dosimetric comparison of intensity modulated and volumetric arc radiation therapy for gastric cancer

The aim of the present study was to compare radiotherapy treatment plans for gastric cancer using intensity-modulated radiotherapy (IMRT) and single/double-arc volumetric modulated arc therapy (SA/DA-VMAT) delivery techniques. A total of 29 postoperative gastric cancer patients were enrolled in this study and each patient was scheduled 5-field IMRT (5F-IMRT), 7-field IMRT (7F-IMRT), SA-VMAT and DA-VMAT techniques. Dose-volume histogram statistics, conformal index (CI), homogeneity index (HI) and monitor units (MUs) were analyzed to compare treatment plans. The DA-VMAT plans exceeded the other three methods in terms of planning tumor volume dose and organs at risk in the kidneys, but not in the liver. DA-VMAT exhibited a better mean CI (0.87±0.03) and HI (0.10±0.01) than the other techniques. In addition, for the kidneys the dose sparing (V13, V18 and mean kidney dose) was improved by DA-VMAT plans. Similar results were observed for MUs. However, 5F-IMRT showed a marginal advantage in V30 and mean dose in normal liver when compared with DA-VMAT. The results of this study suggest that DA-VMAT provides improved tumor coverage when compared with 5F-IMRT, 7F-IMRT and SA-VMAT; however, DA-VMAT exhibits no advantage in liver protection when compared with 5F-IMRT. Further studies are required to establish differences in treatment outcomes among the four technologies.

Preoperative chemoradiation reduces the risk of pancreatic fistula after distal pancreatectomy for pancreatic adenocarcinoma

BACKGROUND

Pancreatic fistula (PF) is a common complication after pancreatectomy. Previous reports indicate that preoperative irradiation decreases the risk of PF after pancreatoduodenectomy. In this context, the impact of preoperative chemoradiation therapy (CRT) on PF formation after distal pancreatectomy is of interest.

METHODS

Fifty-eight patients with pancreatic adenocarcinoma who underwent distal pancreatectomy, including 28 patients with preoperative gemcitabine-based CRT and 30 patients without preoperative treatment, were assessed in this study. The incidence and severity of postoperative PF, assessed according to the definition of the International Study Group on Pancreatic Fistula, were compared between the 2 groups.

RESULTS

In the CRT group, 86% of patients did not develop PF, whereas grades A and B PF were observed in 1 and 3 patients, respectively. In the non-CRT group, 33% of patients did not develop a PF, whereas grades A and B PF were observed in 9 and 11 patients, respectively. The incidence of clinically significant PF, defined as either grade B or grade C PF, was less in the CRT group (P = .031). The amylase activities in the draining fluid on postoperative days 1 and 3 were both less in the CRT group (P = .003 and P = .006, respectively).

CONCLUSION

Preoperative CRT significantly decreases the incidence of PF after distal pancreatectomy, which potentially provides another benefit to patients in addition to its original advantages (ie, locoregional effect and patient selection effect), allowing more opportunities for the immediate initiation of postoperative adjuvant treatment.

Management of painful chronic pancreatitis with single-dose radiotherapy

OBJECTIVES

Some patients with chronic pancreatitis present recurrent flare-ups of pancreatitis and/or unrelenting pain. Current management is mostly limited to analgesics and surgery. We reasoned that anti-inflammatory radiotherapy, which has proven useful to alleviate other painful inflammatory painful disorders, might prove valuable for severely symptomatic patients with chronic pancreatitis.

METHODS

We prospectively studied the efficacy of single-dose anti-inflammatory radiotherapy in 15 consecutive patients with chronic pancreatitis who fulfilled the following criteria: either two flare-ups of pancreatitis in the previous 6 months and/or continuous pain for more than 3 months. Treatment consisted of a single radiation dose of 8 Gy to the pancreas. Exocrine function (fecal elastase), endocrine function (c peptide), quality of life (EuroQol questionnaire), and clinical outcome were assessed before and after radiation. Response was defined as no further pain or flare-ups of pancreatitis.

RESULTS

During follow-up (median: 39 months; range: 4-72 months), 12 patients had no further pain or flare-ups. One patient required a second radiation dose 1 year after the initial treatment, but he has remained well ever since (50 months). Two other patients did not respond to radiotherapy. After radiotherapy either exocrine or endocrine pancreatic function, or both, deteriorated in three patients. Patients who responded to treatment (13/15) gained 4-20 kg in body weight during follow-up (median 4 kg) and EuroQol improved significantly from 0.58 to 0.86 (P<0.001).

CONCLUSIONS

Radiotherapy for severe symptomatic chronic pancreatitis appears to be a useful and effective therapeutic choice that could potentially substitute for or delay surgery.

Influence of X-ray on the autophagic-lysosomal system in rat pancreatic acini

Lysosomes have an important role in radiation injury of cells and tissues. Activation of autophagy is frequently observed in different types of pathological tissue degeneration. In radiation response it increases in some cases, and lysosomes are responsible for regulated degradation of the autophagic vacuoles. Lysosomes are also involved in ionizing radiation induced cell death. In apoptosis lysosomes degrade content of the phagocytotic vacuoles derived from engulfed apoptotic blebs. On the other hand lysosomal enzymes discharged from disintegrated cells have a key role in induction of necrotic changes. In this work we investigate autophagy and lysosomal protein degradation in the relatively radiation insensitive exocrine pancreatic acini in vivo and in vitro. Type of cell death induced by X-ray was also examined in relation to the changes of the lysosomal processes. In 5h after 16 Gy in vivo whole body irradiation we observed significant increase in the cytoplasmic volume fraction of autophagic vacuoles and in the number of apoptotic cells in vivo. But in the acini isolated from irradiated rats we could not detect a change in the lysosomal degradation of intracellular proteins. Therefore irradiation probably influences the autophagy in an earlier step than lysosomal degradation. Extended necrotic lesions were not observed in vivo as long as 48 h. Isolated pancreatic acini usually contain more autophagic vacuoles than in vivo, but we could not observe additional increase in autophagy after 8 Gy, in vitro irradiation. Lysosomal degradation of intracellular proteins was also unaltered after 8 Gy, in vitro irradiation. Other biochemical functional parameters of the isolated pancreatic acini, like protein synthesis and amylase secretion were not changed either after 8 Gy, in vitro X-ray treatment. These results indicate that pancreatic acinar cells in vitro have a high tolerance to irradiation. The observed in vivo radiation induced changes of the exocrine pancreas are possibly indirectly induced by injuries of more sensitive mechanisms.

Intraoperative radiotherapy for pancreatic carcinoma. Experimental and clinical studies

Intraoperative radiotherapy (IORT) is an innovative treatment approach that has been tested in several Phase I-II studies and small Phase III trials in patients with resectable and unresectable pancreatic cancer. The technical approach and dose guidelines for adjacent normal tissues have been established in a series of experiments using a large animal (canine) model. This article reviews the experimental and clinical studies of IORT in cancer of the pancreas.

Experimental and clinical studies of intraoperative radiation therapy

Intraoperative radiation therapy (IORT) is an innovative treatment modality that has recently been given considerable attention as an approach toward controlling various locally advanced cancers. IORT involves surgical extirpation or debulking of the malignant lesion and the delivery of a large single dose of radiation to the tumor bed or to residual disease. This strategy allows for a theoretical enhancement of the therapeutic effect of radiation for three reasons: (1) the biologic effectiveness of a single large radiation dose is higher than for the same dose given in a fractionated regimen; (2) the dose of radiation is precisely given to the area at greatest risk of tumor recurrence (or persistence); and (3) irradiation of dose-limiting normal tissues may be avoided by operative mobilization of the tissues from the treatment volume by customized lead shielding of anatomically fixed structures or by judicious choice of electron beam energies or use of a bolus to limit dose to deep structures. Electrons are generally used for IORT because of sharp dose falloff. This avoids potential toxic effects to normal structures that may lie deep to the treatment volume. Conventional external beam photon radiation therapy (EBRT) allows less accurate tumor volume delineation (even with sophisticated treatment planning technique) and dose limitations necessitated by normal tissues incidentally in the treatment volume. A considerable amount of experimental and clinical data are available on the acute and late effects of IORT on normal tissues. Dose tolerances of many organs have been described in large animal models, and clinical toxicities are evident in several trials. Clinical IORT treatments are provided in more than 250 U.S. and foreign centers at the present time. Given the current interest in IORT, this monograph will review IORT methods and experimental and clinical results with emphasis on its present and future role for locally advanced cancers.

Abdominal radiotherapy is a cause for chronic pancreatitis

We report a series of five patients with nonalcoholic chronic pancreatitis who underwent abdominal radiotherapy for Hodgkin's disease (n = 4) or seminoma (n = 1) at doses ranging from 3600 to 4050 rads, 6 to 20 years (median, 7 years) before the onset of pancreatitis. Patients were in complete remission for their malignant disease. Other causes of chronic pancreatitis were excluded. The manifestations of chronic pancreatitis (median follow-up after the diagnosis of pancreatitis, 5 years) were pancreatic pain (n = 5), acute pancreatitis (n = 3), pseudocysts (n = 3), common bile duct stenosis (n = 2), duodenal stenosis (n = 1), splenic vein obstruction (n = 1), diabetes mellitus (n = 4), steatorrhea (n = 4), and pancreatic calcifications (n = 1). Other abdominal radiation injuries were severe chronic ulcer of the genu superius (n = 1), stenosis at the junction of the right and left hepatic ducts (n = 1), and splenic and left renal atrophy (n = 1). In one patient, pathological examination of the pancreas showed signs of chronic pancreatitis, severe fibrous endarteritis, and lack of inflammation. Abdominal radiotherapy should be added to the list of causes of chronic pancreatitis. We suggest that the physiopathology of postradiotherapy chronic pancreatitis is a vascular process.

Intraoperative radiation therapy following pancreaticoduodenectomy

OBJECTIVE

To determine the morbidity and mortality of pancreaticoduodenectomy followed by electron-beam intraoperative radiation therapy (EB-IORT).

SUMMARY BACKGROUND DATA

Local recurrence following pancreaticoduodenectomy occurs in 50% to 90% of patients who undergo a potentially curative surgical resection for adenocarcinoma of the pancreatic head. To improve local disease control, a more aggressive retroperitoneal dissection has been combined with adjuvant EB-IORT.

METHODS

Forty-one patients with malignant neoplasms of the periampullary region underwent pancreaticoduodenectomy followed by EB-IORT between January 1989 and May 1992. EB-IORT was delivered in a dedicated operative suite, eliminating the need for patient relocation. Electron-beam energies of 6 to 12 MeV were used to deliver 10 to 20 Gy to the treatment field following resection but before pancreatic, biliary, and gastrointestinal reconstruction.

RESULTS

Median operative time was 9 hours, blood loss was 1 L, perioperative transfusion requirement was 2 units, and hospital stay was 20 days. One patient died of a postoperative myocardial infarction, and four patients required reoperation, one for an anastomotic leak. No patient failed to receive EB-IORT because of operative complications during the time period of this study.

CONCLUSION

Adjuvant EB-IORT after pancreaticoduodenectomy can be delivered safely, with low mortality and acceptable morbidity.