Intraoperative radiotherapy in resected pancreatic cancer: feasibility and results

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.

Preoperative Chemoradiation and Intra-Operative Radiotherapy for Pancreatic Carcinoma

Aims and background

In recent years, preoperative chemoradiation has received growing interest for the treatment of locally advanced pancreatic cancer. In an attempt to improve resectability and disease control, we used preoperative radiation therapy and concomitant 5-fluorouracil in a combined modality therapy protocol. The aim of the study was to evaluate definitive results in terms of toxicity, response and clinical outcome.

Material and methods

Twenty-eight patients with unresectable (cT4,19 patients) or resectable (cT3, 9 patients) nonmetastatic pancreatic tumors received radiotherapy (39.6 Gy) plus 5-fluorouracil (continuous infusion, days 1-4 at 1000 mg/m2/day). After 4 weeks, patients were evaluated for surgical resection. In 9 resected patients, electron-beam intra-operative radiotherapy (10 Gy) was given before reconstruction. Thereafter, in resected patients, adjuvant chemotherapy was prescribed.

Results

During chemoradiation, 1 patient (3.6%) developed grade 3 acute gastrointestinal toxicity and 2 patients (7.1%) developed grade 3 hematological toxicity. Three of 19 patients with unresectable tumors had tumor downstaging (15.8%). Two patients showed partial response (response rate, 7.1%; 95% CI, 0.2-25.3) and 4 patients (14.3%) had minimal tumor response. Four patients (14.3%) showed progressive disease after chemoradiation. One postoperative death was recorded. The median survival time was 11.3 months (20.5 and 9.0 months in resected and unresected patients, respectively). Only one local failure was recorded in 8 patients resected with negative margins.

Conclusions

Although the response rate is still low, our preliminary results suggest that preoperative 5-fluorouracil chemoradiation is well tolerated and may result in tumor downstaging. Delivery of intra-operative radiotherapy seems to be associated with a low rate of local recurrences.

Adjuvant therapy for pancreatic cancer

Pancreatic cancer is a challenging malignancy to treat, as less than one-fifth of diagnosed cases are resectable, surgery is complex and postoperative recovery slow, treated patients tend to relapse and overall survival rates are low. It is one of the leading causes of cancer-related mortality. Adjuvant therapy has been employed in resectable disease, to target micrometastases and improve prognosis. Chemotherapy, chemoradiotherapy (chemoRT) and chemoradiotherapy (chemoRT) followed on by chemotherapy have been evaluated in randomised controlled trials. The European Study Group for Pancreatic Cancer (ESPAC)-1 and CONKO-001 trials clearly established the survival advantage of adjuvant chemotherapy with 5 fluorouracil (5FU) plus folinic acid and gemcitabine respectively over no chemotherapy. The ESPAC-3 (version 2) trial demonstrated equivalence between 5FU plus folinic acid and gemcitabine in terms of survival parameters, though gemcitabine had a better toxicity profile. The results of these key studies, together with smaller ones have been subjected to meta-analyses, with confirmation of improved survival with adjuvant systemic chemotherapy. The EORTC-40891 and ESPAC-1 trials found no survival advantage with adjuvant chemoRT compared to observation, and this has been reflected in a subsequent meta-analysis. The popularisation of chemoRT, with follow on chemotherapy (versus observation) was based on the small underpowered GITSG trial. The ESPAC-1 trial was unable to find a survival benefit for chemoRT, with follow on chemotherapy compared to observation. The RTOG-9704 trial assessed chemoRT with follow on chemotherapy in both arms and found no difference between survival in the gemcitabine and 5FU arms. There has never been a published head-to-head randomised comparison of adjuvant chemotherapy to chemoRT, with follow on chemotherapy. Ongoing randomised trials are looking into adjuvant combination chemotherapy, chemotherapy with follow on chemoRT, and neoadjuvant therapy. Novel agents continue to be assessed in early phase trials with a major emphasis on predictive and prognostic biomarkers. Based on the available evidence, adjuvant chemotherapy with gemcitabine or 5FU/folinic acid is the current recommended gold standard in the management of resected pancreatic cancer.

Adjuvant treatment

Exocrine pancreatic cancer (pancreatic ductal adenocarcinoma) is one of the leading causes of cancer deaths in the western world, accounting for 5% of all cancer-related deaths. Only a small percentage of patients with pancreatic cancer are able to undergo potentially curative resection, even in specialized centres, and prognosis remains poor after successful surgery. Over the last few years efforts have been directed towards the development of adjuvant therapies in attempts to improve outcome. The main trials of adjuvant chemotherapy, chemoradiotherapy and chemoradiotherapy with follow-on chemotherapy are described in this paper, followed by the results of the ESPAC-1 trial and the status of ESPAC-2 and -3 trials.

The evolving role of postoperative adjuvant radiation therapy for pancreatic cancer

The benefit of postoperative adjuvant chemoradiation in the treatment of resected pancreatic cancers was first established by a randomized trial conducted by the Gastrointestinal Tumor Study Group in 1974. During the past 3 decades, treatment has evolved toward more dose-intensive regimens of chemoradiation. Historical split-course conventional radiation therapy has been replaced by continuous-course radiotherapy to higher doses, and gemcitabine is being actively investigated as a potentially more effective agent than 5-fluorouracil. This article critically examines the results of important randomized multi-institutional trials and reviews the evolution toward dose-intensive adjuvant treatment regimens. Implications of the recently completed intergroup study are discussed, modern radiation therapy delivery techniques are reviewed, and suggestions for future trials are made.

A study of radiotherapy modalities combined with continuous 5-FU infusion for locally advanced gastrointestinal malignancies

AIM

We describe the feasibility of combining infusional 5-fluorouracil (5-FU) with intraoperative radiation therapy (IORT).

METHODS

Patients with surgically resectable locally advanced gastrointestinal cancers were treated concurrently during surgery with IORT and a 72 h infusion of 5-FU. Patients without previous external beam radiation therapy (EBRT) were subsequently treated with EBRT (40-50Gy) concurrent with a 21-day continuous infusion of 5-FU. Pancreatic, gastric, duodenal, ampullary, recurrent colorectal, and recurrent anal cancer were included.

RESULTS

During IORT/5-FU, no chemotherapy-related grade III or IV hematologic or gastrointestinal toxicity was noted. Post-surgical recovery or wound healing was not affected. One of nine patients who received post-operative radiation required a treatment break. During follow-up, there were more complications in patients with pelvic tumours, especially those with previous radiation. Nine patients have had local and/or local regional recurrences, two of these in the IORT field.

CONCLUSIONS

Treatment with a combination of IORT and 5-FU followed by EBRT and 5-FU is feasible. However, long-term complications may be increased in previously irradiated recurrent pelvic tumours.

The role of intraoperative radiotherapy in pancreatic cancer

In single-institution studies, IORT at appropriate doses seems to safely improve local control in patients who have locally advanced pancreatic cancer, compared with historical controls. IORT also has been a component of adjuvant treatment programs that have led to excellent local control in resected patients. When considering the use of IORT, it is essential to have an understanding of the physical characteristics of the electron beam and how it can differ with the use of flat and beveled applicators. Although apparent improvement in local control with the use of IORT seems to have produced some improvement in median survival rates, high rates of distant failure continues to prevent a significant improvement in long-term survival. Because effective local control in patients with unresectable pancreatic cancer is a prerequisite to the development of curative therapies, the development of improved systemic therapies in patients with locally advanced pancreatic cancer will likely make local therapies such as the use of IORT even more important in the future.

Radiotherapy techniques in current use in Sweden

A systematic assessment of radiotherapy for cancer was conducted by The Swedish Council on Technology Assessment in Health Care (SBU) in 2001. The assessment included a review of radiotherapy techniques in current use in Sweden. The following conclusions were drawn: Radiotherapy demands adequate knowledge of diagnostic methods, anatomy, cancer biology and of the physical and biological properties of ionizing radiation. Well-functioning teamwork on the part of the oncologist, medical physicist and oncology nurse is important. Radiotherapy has a high degree of technical sophistication, including the use of computers, which necessitates expert technical support. Technical development is rapid, and since the previous report, multileaf collimators and electronic portal imaging have been introduced in the clinical routine. The use of brachytherapy for treatment of non-gynaecological malignancies is rapidly increasing. The need for quality assurance in all steps of the radiotherapy procedure is stressed. A critical review of the literature on intraoperative radiotherapy is also included as an Appendix.

Impact of intraoperative radiation on postoperative and disease-specific outcome after pancreatoduodenectomy for adenocarcinoma: a propensity score analysis

For periampullary cancer,intraoperative radiation therapy (IORT) administered to the site with the highest locoregional recurrence risk carries the rationale to improve tumor control. An IORT effect on survival remains unclear. IORT impact on postoperative outcomes after pancreatectomy for adenocarcinoma was analyzed, with a specific attempt to correct for the nonrandom IORT treatment assignment, and to account for treatment group imbalances in the interpretation of outcome differences. A propensity-score-adjusted analysis, based on variable selection by logistic regression, was used to rebalance treatments. Between 1989 and 1999, 61 patients underwent partial or total pancreatectomy for a primary periampullary adenocarcinoma at the City of Hope National Medical Center. Diagnoses included pancreatic (n = 36), duodenal (n = 11), ampullary (n = 10), and bile duct cancer (n = 4). Thirty patients received IORT to the resection area, with a median dose of 15 Gy (range: 10-20), followed by postoperative external beam radiation (n = 24). Mortality was 0%, the complication rate 61%. Of 33 patients with a documented recurrence, 6 had an isolated locoregional recurrence only (1 IORT versus 5 no IORT, = 0.05); the systemic recurrence pattern differed as well (IORT 94%, no IORT 67%; = 0.04). IORT had no significant impact on hospital stay (overall median: 17 days), disease-free survival (16 months), and overall survival (23 months) when adjusted for those most relevant variables reflecting IORT treatment group assignment propensity. After adjustment for relevant propensity factors, IORT was not linked to a significantly increased risk for complications, hospital stay, or survival hazard. The recurrence pattern may be affected in some patients, but systemic recurrences predominate. We continue to explore IORT in combination with systemic chemotherapy.

Adjuvant radiotherapy in resectable pancreatic carcinoma

AIM

Pancreatic cancer is a near fatal disease. External beam radiotherapy and intraoperative radiation therapy (IORT) has been proposed with the aim to improve clinical outcome in resectable tumors. The aim of this study is to assess the feasibility and outcome in patients with cT1-3 pancreatic cancer, treated with surgery, external beam radiotherapy and IORT.

METHODS

From 1990 to 1996, 17 patients with clinical stage T1-3N0-1M0 adenocarcinoma of the head of the pancreas were treated with pancreatectomy and pre- (nine patients: 5 Gy), intra- (all patients: 10 Gy) and post-operative (all patients: 50 Gy) radiotherapy. The pathologic T stages were: 4 pT2 and 13 pT3. The pathologic N stages were: 9 pN0 and 8 pN1. Minimum follow-up in living patients was 60 months.

RESULTS

No perioperative mortalities were recorded. Two patients showed postoperative morbidity (11.8%) which required a subsequent laparotomy. The disease-free survival at 1, 3 and 5 years was 41, 23 and 18%, respectively (median: 9 months). The overall survival at 1, 3 and 5 years was 70%, 41% and 18%, respectively (median: 17.5 months). Three patients developed local failure (17.6%) and 12 patients showed distant metastases (70.6%). Univariate analysis (logrank) showed: a significant correlation between both N-stage and retroperitoneal involvement (RPI) with local control (N-stage: P=0.0155; RPI:P =0.0295), a significant correlation between maximum tumor size and metastases-free survival (P=0.0167) and overall survival (P=0.0241); the female gender was another predictor of prolonged survival (P= 0.0465). Multivariate analysis (Cox) showed a significant impact of N-stage and retroperitoneal involvement on local control and also a significant correlation between perineural involvement and tumor diameter with metastases-free survival.

CONCLUSIONS

These results are similar to those of other published series and suggest that this approach is feasible with acceptable local control and survival, especially in patients with small tumors (<2.5 cm: 5 year survival=33.3%) and in female patients (5 year survival=30%). Due to the impact of gender, tumor diameter and N stage on prognosis, in the design of future trials a stratification of patients based on these categories should be considered. The search of effective chemotherapeutic agents is required, to reduce the high incidence of distant metastases, especially in larger tumors.

Current status of and future prospects for the medical management of adenocarcinoma of the exocrine pancreas

Adenocarcinoma of the exocrine pancreas is one of the most refractory neoplasms to medical treatment. Although of marginal value, 5-fluorouracil (5-FU) alone or in combination with other agents or modalities has been the standard surgical adjuvant approach to localized unresectable tumor as well as the standard treatment for disseminated pancreatic cancer. Recently, a new chemotherapeutic agent, gemcitabine, has been shown to be somewhat more effective than 5-FU against metastatic pancreatic cancer. Treatment with gemcitabine usually results in a greater likelihood of objective response and better symptom control than treatment with 5-FU or drug combinations that include 5-FU. However, treatment with gemcitabine does not improve overall survival of patients with disseminated neoplasm. Newer promising agents such as 9-nitrocamptothecin have recently entered clinical trials, and novel modalities (e.g., gene therapy) are nearing full-scale clinical trial. There are reasons to believe that these and other new initiatives may soon significantly improve the medical management of adenocarcinoma of the exocrine pancreas.

[Concomitant chemoradiotherapy and preoperative radiotherapy in exocrine pancreatic adenocarcinoma]

The prognosis of pancreatic adenocarcinoma remains poor, with a 5-year survival rate lower than 5%. Resection, the gold standard treatment, can be performed in less than 10% of patients. Following surgery, the median survival is 12 months. Concomitant chemoradiation, as an adjuvant treatment could be superior to surgery alone, in terms of survival; controlled trials are currently performed. Neoadjuvant chemoradiation is a new approach, potentially able to increase survival and resection rate. Finally, current data regarding intraoperative irradiation are exposed.

[Adenocarcinoma of the exocrine pancreas: management and therapeutic hopes]

INTRODUCTION

Pancreatic carcinoma is a major public health concern, as it kills more than 6,000 people each year in France.

CURRENT KNOWLEDGE AND KEY POINTS

The main risk factor demonstrated by concordant case-control studies is cigarette smoking. Pancreatic carcinoma is generally diagnosed at an advanced stage. Results of radical surgery are still poor. In most of the reported series, less than 25% of the patients survive at five years.

FUTURE PROSPECTS AND PROJECTS

Postoperative radiochemotherapy slightly increases the hope of cure. In locally advanced tumors, radiochemotherapy, sometimes preoperative, allows some patients to survive more than two years. Though results of palliative chemotherapy remain very poor, some clinical benefit has been observed in randomized trials comparing this treatment with the currently best supportive treatment.

La Radioterapia Intraoperatoria Nel Trattamento Integrato Del Carcinoma Pancreatico

Pancreatic cancer is a highly lethal disease either for the high incidence of distant metastases or for the frequent local recidive also after potentially curative resection. For this reason new multimodality approaches have to be investigated. Intraoperative radiotherapy (IORT) permits to administer a high dose to the tumor or to the retropancreatic tissues and to the regional lymphnodes. Literature data suggest it is possible a better local control and pheraps a better survival than the surgery alone or the palliative treatments by the use of schedules with IORT. Anyway they are retrospective data and IORT is an investigational method which has to be indagate in the combined modality approaches to this disease.

[Intraoperative radiotherapy in 1997]

Intra Operative Radiation Therapy (IORT) has been routinely used for the past 20 years. It is a feasible treatment, with a reasonable cost and an acceptable acute and late toxicity. There is so far no strong randomized trial demonstrating that IORT can improve overall survival. Nevertheless, in many institutions it is recognized as an efficient treatment in selected patients. In case of locally recurrent disease an incomplete gross resection is often the only choice; IORT in such a situation has led to very encouraging results. For locally advanced deep seated primary tumors IORT seems to improve local control. In the near future IORT should be used on a larger and stronger basis. The manufacturing of new mobile linac should allow more surgeons to perform IORT and to conduct clinical trials to confirm the present indications in cancers with high local malignancy.