Early experience with intraoperative radiotherapy in patients with resected pancreatic adenocarcinoma

Clinical Outcomes of Intraoperative Radiotherapy, Postoperative Radiotherapy, and Definitive Radiotherapy for Non-metastatic Pancreatic Cancer

OBJECTIVE

The aim of this study is to evaluate the utility of adjuvant radiotherapy (intraoperative radiotherapy, IORT; postoperative radiotherapy, PORT), and definitive radiotherapy for non-metastatic pancreatic cancer.

METHODS

Ninety-nine patients were analyzed. Thirty patients underwent IORT with surgery, 31 underwent PORT after surgery, and 38 underwent definitive radiotherapy. Tumor stage [Union for International Cancer Control (UICC) 2009] was as follows: Stage I, 7; IIA, 16; IIB, 31; III, 45. The doses for IORT, PORT, and definitive radio therapy were 20 to 30, 40 to 64.6, and 50.4 to 61.2 Gy, respectively. Associations between clinical parameters including age, gender, tumor site, stage, performance status, surgical margin, and use of chemotherapy and local control (LC) or overall survival (OS) were analyzed.

RESULTS

Follow-up periods for all patients were 1.1-145 months (median, 11). OS rate in the IORT, PORT, and definitive radiotherapy groups was 22%, 16%, and 6%, respectively, at 2 years. The 5-year OS rate was 13%, 3.2%, and 0%, respectively. Local control rate at 2 years was 33%, 35%, and 0%, respectively. No Grade ≥ 3 tox icities were observed. Distant metastasis was less common in the IORT group. Stage and surgical margin were sig nificant factors for OS after IORT. Performance status and chemotherapy were significant factors for OS after PORT and definitive radiotherapy.

CONCLUSIONS

The present study showed the safety of the three treatment modalities, but the outcomes were not satisfactory. More intensive strategies including radiotherapy should be investigated.

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.

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.

Present status and future directions of intraoperative radiotherapy

In this Review, we summarise recent published work on the use of intraoperative radiotherapy to treat common tumour sites in the primary or recurrent setting. Techniques, radiobiology, and the physics of intraoperative radiotherapy are also explored. Disease sites discussed in this Review include head and neck cancer, breast cancer, sarcoma, gastrointestinal cancer, genitourinary cancer, gynaecological cancer, thoracic cancer, and palliative applications.

Intraoperative radiotherapy for resected pancreatic cancer: a multi-institutional retrospective analysis of 210 patients

PURPOSE

To retrospectively analyze the results of intraoperative radiotherapy (IORT) with or without external beam radiotherapy (EBRT) for resected pancreatic cancer.

METHODS AND MATERIALS

The records of 210 patients treated with gross complete resection (R0: 147 patients; R1: 63 patients) and IORT with or without EBRT were reviewed. One hundred forty-seven patients (70.0%) were treated without EBRT and 114 patients (54.3%) were treated in conjunction with chemotherapy. The median doses of IORT and EBRT were 25 Gy (range, 20-30 Gy) and 45 Gy (range, 20-60Gy), respectively. The median follow-up of the surviving 62 patients was 26.3 months (range, 2.7-90.5 months).

RESULTS

At the time of this analysis, 150 of 210 patients (71.4%) had disease recurrences. Local failure was observed in 31 patients (14.8%), and the 2-year local control rate in all patients was 83.7%. The median survival time and the 2-year actuarial overall survival (OS) in all 210 patients were 19.1 months and 42.1%, respectively. Patients treated with IORT and chemotherapy had a significantly more favorable OS than those treated with IORT alone (p = 0.0011). On univariate analysis, chemotherapy use, degree of resection, carbohydrate antigen 19-9, and pathological N stage had a significant impact on OS and on multivariate analysis; these four factors were significant prognostic factors. Late gastrointestinal morbidity of NCI-CTC Grade 4 was observed in 7 patients (3.3%).

CONCLUSION

IORT yields an excellent local control rate for resected pancreatic cancer with few frequencies of severe late toxicity, and IORT combined with chemotherapy confers a survival benefit compared with that of IORT alone.

Molecular targeted therapies for pancreatic cancer

BACKGROUND

Pancreatic cancer cells express different mutations that increase the aggressiveness and confer resistance to conventional chemotherapy and radiotherapy. Molecules that selectively bind and inhibit these mutations are effective in other solid tumors and are now emerging as a complementary therapy in pancreatic cancer. The objective of this review is to describe the effect of drugs that inhibit specific mutations present in pancreatic cancer with special emphasis on clinical trials.

DATA SOURCES

We reviewed the English-language literature (MedLine) addressing the role of drugs that target mutations present in pancreatic cancer. Both preclinical and clinical studies were included.

CONCLUSIONS

Preclinical evidence supports the combination of conventional approved therapies plus drugs that block epidermal growth factor receptor and vascular growth endothelial factor or induce apoptosis. However, most of the current clinical evidence is limited to small phase I trials evaluating the toxicity and safety of these regimens. The results of additional randomized trials that are still undergoing will clarify the role of these drugs in pancreatic cancer.