Intraoperative radiation therapy opportunities for clinical practice normalization: Data recording and innovative development

Intra-Operative Electron Radiation Therapy: An Update of the Evidence Collected in 40 Years to Search for Models for Electron-FLASH Studies

Simple Summary

Four decades ago, intraoperative electron radiation therapy (IOeRT) was developed to improve precision in local cancer treatment by combining real-time surgical exploration and resection with high-energy electron irradiation. The technology of ultra-high dose rate electron and other radiation beams known as FLASH irradiation sharply increases its interests, as data from preclinical experiments have proven a marked favorable effect on the therapeutic index: similar cancer control with a clearly improved tolerance of many normal tissues to high doses of irradiation. The knowledge and tools regarding technology, physics, biology, and preclinical results in heterogeneous cancers opens great opportunities towards the path of developing the first clinical applications of the emerging FLASH technology via clinical trials based on state-of-the-art medical practice with IOeRT.

Abstract

Introduction: The clinical practice and outcome results of intraoperative electron radiation therapy (IOeRT) in cancer patients have been extensively reported over 4 decades. Electron beams can be delivered in the promising FLASH dose rate. Methods and Materials: Several cancer models were approached by two alternative radiobiological strategies to optimize local cancer control: boost versus exclusive IOeRT. Clinical outcomes are revisited via a bibliometric search performed for the elaboration of ESTRO/ACROP IORT guidelines. Results: In the period 1982 to 2020, a total of 19,148 patients were registered in 116 publications concerning soft tissue sarcomas (9% of patients), unresected and borderline-resected pancreatic cancer (22%), locally recurrent and locally advanced rectal cancer (22%), and breast cancer (45%). Clinical outcomes following IOeRT doses in the range of 10 to 25 Gy (with or without external beam fractionated radiation therapy) show a wide range of local control from 40 to 100% depending upon cancer site, histology, stage, and treatment intensity. Constraints for normal tissue tolerance are important to maintain tumor control combined with acceptable levels of side effects. Conclusions: IOeRT represents an evidence-based approach for several tumor types. A specific risk analysis for local recurrences supports the identification of cancer models that are candidates for FLASH studies.

Familial aggregation of gastric cancer with microsatellite instability

BACKGROUND

Microsatellite instability (MSI) is currently a new molecular subtype of gastric cancer (GC). About 90% of GC cases appear sporadically. MSI seems to be responsible for both sporadic and familial GC. The aim of this study was to analyze the frequency of MSI in GC with familial history of GC.

METHODS

The MSI analysis was conducted using five quasi-monomorphic mononucleotide repeats: BAT-26, BAT-25, NR-24, NR-21 and NR-27. From our database, we analyzed 457 patients in terms of cancer history across family members, particularly focusing on GC.

RESULTS

MSI status in patients without familial history of GC was present in 22.1% of the cases, whereas in the patients with familial history of GC it was present in 28% of the cases (p = 0.220). For 1st or 2nd degree family members with GC, MSI was observed in 27.6% and in 30.8%, respectively (p = 0.812). MSI was observed in hereditary gastric cancer (HGC) in 33.3% and in familial gastric cancer (FGC) in 30%. No difference in survival rates was observed between the analyzed groups.

CONCLUSIONS

In our publication, we could not find any link between familial background and the MSI status in GC patients. More detailed molecular and genetic analysis of subgroups of these patients is required.

The role of intraoperative radiotherapy (IORT) in the management of patients with pancreatic and periampullary cancer: A single center experience

BACKGROUND

In spite of the advances in modern surgery, the outcome for patients suffering from pancreatic adenocarcinoma or periampullary adenocarcinoma is still bad. Recently, introperative radiotherapy (IORT) was introduced into the multimodality management approach to improve both tumor control and patient' survival.

AIM OF WORK

To evaluate our initial experience in combined surgical resection and IORT, and to evaluate the feasibility of the application of IORT and its effect on morbidity, mortality and local recurrence.

PATIENTS AND METHODS

This study was conducted at King Faisal Specialist Hospital and Research Center, Riyadh, Kingdom of Saudi Arabia. Data were collected retrospectively. A total of six patients were included in the study, during the period from November 2013 to April 2017. All surgeries were done by the same surgeon.

RESULTS

The average age was 60 years (50-71). The patients were four males and two females. Five patients underwent complete surgical resection (pancreaticoduodenectomy) combined with IORT. One patient had locally advanced pancreatic tumor which was beyond surgical resection, for whom surgical bypass was done to overcome the biliary obstruction combined with IORT. Two patients died from disease progression and liver metastases. The remaining four patients survived without any evidence of local recurrence or metastases on follow-up.

CONCLUSION

Application of IORT is safe and feasible. It can be applied without additional morbidities or mortalities. Although our results are satisfactory, yet they need to be applied on a larger number of patients with longer periods of follow-up to reach sound conclusions.

Single Center Experience on Anatomy-and Histopathology-Based Gastric Cancer Molecular Classification

We analyzed the clinical utility of molecular classification based on anatomical and histological background. The study was conducted on 457 patients treated for gastric cancer with additional information about microsatellite instability status. We divided the patients in three groups of molecular classification based on anatomical and histological background: proximal non-diffused, diffused, and distal non-diffused groups. These groups varied in terms of clinical and pathological factors as well as survival rates. The molecular classification based on anatomical and histological data seems to be a useful tool in a simple classification of gastric cancer.

Intraoperative irradiation: precision medicine for quality cancer control promotion

Intraoperative irradiation was implemented 4 decades ago, pioneering the efforts to improve precision in local cancer therapy by combining real-time surgical exploration/resection with high single dose radiotherapy (Gunderson et al., Intraoperative irradiation: techniques and results, 2011). Clinical and technical developments have led to very precise radiation dose deposit. The ability to deliver a very precise dose of radiation is an essential element of contemporary multidisciplinary individualized oncology.

This issue of Radiation Oncology contains a collection of expert review articles and updates with relevant data regarding intraoperative radiotherapy. Technology, physics, biology of single dose and clinical results in a variety of cancer sites and histologies are described and analyzed. The state of the art for advanced cancer care through medical innovation opens a significant opportunity for individualize cancer management across a broad spectrum of clinical practice. The advantage for tailoring diagnostic and treatment decisions in an individualized fashion will translate into precise medical treatment.

Practical issues regarding angular and energy response in in vivo intraoperative electron radiotherapy dosimetry

AIM

To estimate angular response deviation of MOSFETs in the realm of intraoperative electron radiotherapy (IOERT), review their energy dependence, and propose unambiguous names for detector rotations.

BACKGROUND

MOSFETs have been used in IOERT. Movement of the detector, namely rotations, can spoil results.

MATERIALS AND METHODS

We propose yaw, pitch, and roll to name the three possible rotations in space, as these unequivocally name aircraft rotations. Reinforced mobile MOSFETs (model TN-502RDM-H) and an Elekta Precise linear accelerator were used. Two detectors were placed in air for the angular response study and the whole set of five detectors was calibrated as usual to evaluate energy dependence.

RESULTS

The maximum readout was obtained with a roll of 90° and 4 MeV. With regard to pitch movement, a substantial drop in readout was achieved at 90°. Significant overresponse was measured at 315° with 4 MeV and at 45° with 15 MeV. Energy response is not different for the following groups of energies: 4, 6, and 9 MeV; and 12 MeV, 15 MeV, and 18 MeV.

CONCLUSIONS

Our proposal to name MOSFET rotations solves the problem of defining sensor orientations. Angular response could explain lower than expected results when the tip of the detector is lifted due to inadvertent movements. MOSFETs energy response is independent of several energies and differs by a maximum of 3.4% when dependent. This can limit dosimetry errors and makes it possible to calibrate the detectors only once for each group of energies, which saves time and optimizes lifespan of MOSFETs.

Failure mode and effect analysis oriented to risk-reduction interventions in intraoperative electron radiation therapy: the specific impact of patient transportation, automation, and treatment planning availability

BACKGROUND AND PURPOSE

Industrial companies use failure mode and effect analysis (FMEA) to improve quality. Our objective was to describe an FMEA and subsequent interventions for an automated intraoperative electron radiotherapy (IOERT) procedure with computed tomography simulation, pre-planning, and a fixed conventional linear accelerator.

MATERIAL AND METHODS

A process map, an FMEA, and a fault tree analysis are reported. The equipment considered was the radiance treatment planning system (TPS), the Elekta Precise linac, and TN-502RDM-H metal-oxide-semiconductor-field-effect transistor in vivo dosimeters. Computerized order-entry and treatment-automation were also analyzed.

RESULTS

Fifty-seven potential modes and effects were identified and classified into 'treatment cancellation' and 'delivering an unintended dose'. They were graded from 'inconvenience' or 'suboptimal treatment' to 'total cancellation' or 'potentially wrong' or 'very wrong administered dose', although these latter effects were never experienced. Risk priority numbers (RPNs) ranged from 3 to 324 and totaled 4804. After interventions such as double checking, interlocking, automation, and structural changes the final total RPN was reduced to 1320.

CONCLUSIONS

FMEA is crucial for prioritizing risk-reduction interventions. In a semi-surgical procedure like IOERT double checking has the potential to reduce risk and improve quality. Interlocks and automation should also be implemented to increase the safety of the procedure.

Intraoperative radiotherapy with electrons: fundamentals, results, and innovation

Rationale and objectives

To analyse the programme activity and clinical innovation and/or technology developed over a period of 17 years with regard to the introduction and the use of intraoperative radiotherapy (IORT) as a therapeutic component in a medical–surgical multidisciplinary cancer hospital.

Material and methods

To standardise and record this procedure, the Radiation Oncology service has an institutional programme and protocols that must be completed by the different specialists involved. For 17 years, IORT procedures were recorded on a specific database that includes 23 variables with information recorded on institutional protocols.

As part of the development and innovation activity, two technological tools were implemented (RADIANCE and MEDTING) in line with the standardisation of this modality in clinical practice.

Results

During the 17 years studied, 1,004 patients were treated through 1,036 IORT procedures. The state of the disease at the time of IORT was 77% primary and 23% recurrent. The origin and distribution of cancers were 62% gastrointestinal, 18% sarcomas, 5% pancreatic, 2% paediatric, 3% breast, 7% less common locations, and 2% others. The research and development projects have generated a patent on virtual planning (RADIANCE) and proof of concept to explore as a professional social network (MEDTING).

During 2012, there were 69 IORT procedures. There was defined treatment volume (target or target region) in all of them, and 43 were conducted by the virtual planning RADIANCE system. Eighteen have been registered on the platform MEDTING as clinical cases.

Conclusion

The IORT programme, developed in a university hospital with an academic tradition, and interdisciplinary surgical oncology, is a feasible care initiative, able to generate the necessary intense clinical activity for tending to the cancer patient. Moreover, it is a competitive source for research, development, and scientific innovation.