Intraoperative Electron-Beam Radiation Therapy for Pediatric Ewing Sarcomas and Rhabdomyosarcomas: Long-Term Outcomes

Validation of Monte Carlo-based calculations for megavolt electron beams for IORT and FLASH-IORT

In Intra-Operative Radiation Therapy (IORT) the tumour site is surgically exposed and normal tissue located around the tumour may be avoided. Electron applicators would require large surgical incisions; therefore, the preferred mechanism for beam collimation is the IORT cone system. FLASH radiotherapy (FLASH-RT) involves the treatment of tumours at ultra-high dose rates and the IORT cone system can also be used. This study validates the Monte Carlo-based calculations for these small electron beams to accurately determine the dose characteristics of each possible cone-energy combination as well as custom-built alloy cutouts attached to the end of the IORT cone. This will contribute to accurate dose distribution and output factor calculations that are essential to all radiation therapy treatments. A Monte Carlo (MC) model was modelled for electron beams produced by a Siemens Primus LINAC and the IORT cones. The accelerator was built with the component modules available in the BEAMnrc code. The phase-space file generated by the BEAM simulation was used as the source input for the subsequent DOSXYZnrc simulations. Percentage Depth Dose (PDD) data and profiles were extracted from the dose distributions obtained with the DOSXYZnrc simulations. These beam characteristics were compared with measured data for 6, 12, and 18 MeV electron beams for the IORT open cones of diameters 19, 45, and 64 mm and irregularly shaped cutouts. The MC simulations could replicate electron beams within a criterion of 3%/3 mm. Applicator factors were within 0.7%, and cone factors showed good agreement, except for the 9 mm cone size. Based on the successful comparisons between measurement and MC-calculated dose distributions, output factors for the open cones and for small irregularly shaped IORT beams, it may be concluded that the Monte Carlo based dose calculation could replicate electron beams used for IORT and FLASH-IORT.

Feasibility and Safety of Intraoperative Radiotherapy with Low Energy X-ray Photon Therapy for Recurrent Gynecological Cancer: A Case Series

Objectives: To evaluate the feasibility and safety of low energy X-ray photon intraoperative radiotherapy (IORT) as an adjuvant therapy for recurrent gynecological cancer.Methods: Medical records of all recurrence gynecological cancer patients who underwent IORT were reviewed. Results: Between January 2018 and December 2021, five women (including cervical cancer (n = 2), endometrial cancer (n = 2), and uterine leiomyosarcoma (n = 1)), who underwent IORT and surgical resection for recurrent gynecologic cancer were reviewed. A median dose of 15.62 Gy (range, 12 to 20 Gy) was used for IORT. Repeated IORT and surgical resection was performed in two women. Three women experienced local recurrence, and three women died during follow-up. The 1-year local control rate was 60%. The 2-year overall survival rate was 30%. There was no Clavien–Dindo classification grade III–V complication. Conclusion: IORT using low energy X-ray photon therapy seems to be feasible and safe as an adjuvant therapy in women who underwent salvage surgery for recurrent gynecologic cancer. However, large-scale prospective studies are needed to confirm our findings and evaluate its efficacy.

Application of additively manufactured 3D scaffolds for bone cancer treatment: a review

Bone cancer is a critical health problem on a global scale, and the associated huge clinical and economic burdens are still rising. Although many clinical approaches are currently used for bone cancer treatment, these methods usually affect the normal body functions and thus present significant limitations. Meanwhile, advanced materials and additive manufacturing have opened up promising avenues for the development of new strategies targeting both bone cancer treatment and post-treatment bone regeneration. This paper presents a comprehensive review of bone cancer and its current treatment methods, particularly focusing on a number of advanced strategies such as scaffolds based on advanced functional materials, drug-loaded scaffolds, and scaffolds for photothermal/magnetothermal therapy. Finally, the main research challenges and future perspectives are elaborated.

Intraoperative radiation therapy for early stage breast cancer

Background and objective

We report our experiences with Intraoperative radiation therapy (IORT) among breast cancer (BC) patients in our region.

Methods

All patients who received radical IORT from April 2014 on to March 2020 were included in the study. Patient selection criteria included: Age equal or older than 45 years old; All cases of invasive carcinomas (in cases of lobular carcinomas only with MRI and confirmation); Patients who were 45–50 years old with a tumor size of 0–2 cm, 50–55 years old with a tumor size of < 2.5 cm, and those who were ≥ 55 years old with a tumor size of < 3 cm; Invasive tumors only with a negative margin; Negative nodal status (exception in patients with micrometastasis); A positive estrogen receptor status. Primary endpoints included death and recurrence which were assessed using the Kaplan–Meier method.

Results

Overall, 252 patients entered the study. Mean (SD) age of patients was 56.43 ± 7.79 years. In total, 32.9% of patients had a family history of BC. Mean (SD) tumor size was 1.56 ± 0.55 cm. Mean (IQR) follow-up of patients was 36.3 ± 18.7 months. Overall, 8 patients (3.1%) experienced recurrence in follow-up visits (disease-free-survival of 96.1%), among which four (1.5%) were local recurrence, two (0.8%) were regional recurrence and two patients (0.8%) had metastasis. Median (IQR) time to recurrence was 46 (22, 53.7) months among the eight patient who had recurrence. Overall, one patient died due to metastasis in our series. Eleven patients (4.3%) with DCIS in our study received IORT. All these patients had free margins in histopathology examination and none experienced recurrence.

Conclusion

Inhere we reported our experience with the use of IORT in a region where facilities for IORT are limited using our modified criteria for patient selection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-021-01427-5.

The American Brachytherapy Society consensus statement on intraoperative radiation therapy

PURPOSE

Although radiation therapy has traditionally been delivered with external beam or brachytherapy, intraoperative radiation therapy (IORT) represents an alternative that may shorten the course of therapy, reduce toxicities, and improve patient satisfaction while potentially lowering the cost of care. At this time, there are limited evidence-based guidelines to assist clinicians with patient selection for IORT. As such, the American Brachytherapy Society presents a consensus statement on the use of IORT.

METHODS

Physicians and physicists with expertise in intraoperative radiation created a site-directed guideline for appropriate patient selection and utilization of IORT.

RESULTS

Several IORT techniques exist including radionuclide-based high-dose-rate, low-dose-rate, electron, and low-energy electronic. In breast cancer, IORT as monotherapy should only be used on prospective studies. IORT can be considered in the treatment of sarcomas with close/positive margins or recurrent sarcomas. IORT can be considered in conjunction with external beam radiotherapy for retroperitoneal sarcomas. IORT can be considered for colorectal malignancies with concern for positive margins and in the setting of recurrent gynecologic cancers. For thoracic, head and neck, and central nervous system malignancies, utilization of IORT should be evaluated on a case-by-case basis.

CONCLUSIONS

The present guidelines provide clinicians with a summary of current data regarding IORT by treatment site and guidelines for the appropriate patient selection and safe utilization of the technique. High-dose-rate, low-dose-rate brachytherapy methods are appropriate when IORT is to be delivered as are electron and low-energy based on the clinical scenario.

Interstitial brachytherapy for pediatric soft tissue sarcoma: Evolving practice over three decades and long-term outcomes

PURPOSE

Evaluate long-term clinical outcomes, adverse effects, and evolving practice of interstitial brachytherapy (BT) for pediatric soft tissue sarcomas (STS).

METHODS

From September 1984 to December 2014, 105 children (median age 10 years) were included. There were 60 males and 45 females. The majority (74%) had primary lesions. Synovial sarcoma (22%) was the most frequent histology. Treatment included wide local excision and BT with or without external beam radiotherapy (EBRT). Eighty-five (81%) received BT alone.

RESULTS

After a median follow-up of 65 months, local control (LC), disease-free survival (DFS), and overall survival (OS) at 10 years were 83, 66, and 73%, respectively. On univariate analysis, LC was superior with tumors <5 cm versus >5 cm (93% vs. 75%, P = 0.10), Grade I/II versus Grade III tumors (97% vs. 73%, P = 0.01), nonround cell versus round cell histology (89% vs. 72%, P = 0.03), and trunk/extremity versus head and neck/genitourinary sites (87% vs. 57%, P = 0.0001). On multivariate analysis tumor size (P = 0.03) and location (P = 0.002) retained significance. Children receiving BT alone had comparable LC to those receiving BT and EBRT (84% vs. 80%, P = 0.43). There was no difference in LC between LDR versus HDR BT (86% vs. 83%, P = 0.30). Wound complications were seen in 6%. Subcutaneous fibrosis (25%), limb edema (6%), skeletal abnormalities (3%), and neuropathy (1%) were the late complications. One child (0.9%) developed a second malignancy after 7 years.

CONCLUSION

Interstitial BT with or without EBRT results in excellent outcomes. Radical BT alone, when used judiciously, results in excellent local control and function with minimal treatment-related morbidity.

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.

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.

Management of Bone Sarcoma

Treatment of bone sarcoma requires careful planning and involvement of an experienced multidisciplinary team. Significant advancements in systemic therapy, radiation, and surgery in recent years have contributed to improved functional and survival outcomes for patients with these difficult tumors, and emerging technologies hold promise for further advancement.

Adjuvant radiation therapy in resected high-grade localized skeletal osteosarcomas treated with neoadjuvant chemotherapy: Long-term outcomes

PURPOSE

To assess long-term outcomes and toxicity of adjuvant radiotherapy in the post-surgical management of patients with resected high-grade skeletal osteosarcomas.

METHODS AND MATERIALS

Seventy-two patients with primary resected osteosarcomas underwent adjuvant radiotherapy after neoadjuvant chemotherapy from December 1984 to December 2008. Local control (LC), overall survival (OS) and disease-free survival (DFS) were estimated using Kaplan-Meier methods. For survival outcomes potential associations were assessed in univariate and multivariate analyses using the Cox proportional hazards model.

RESULTS

After a median follow-up of 174months (range, 33-363months), 10-year LC, DFS, and OS rates were 82%, 58%, and 73%, respectively. In the multivariate analysis only R1 margin status (p=0.02) remained significantly associated with LC. Patients with tumor necrosis <90% (p=0.04) and R1 resection margin (p=0.05) remained at a significantly higher risk of mortality on multivariate analysis. Six patients (8%) developed grade ⩾3 treatment-related chronic toxicity events. No grade 5 toxicities were reported.

CONCLUSIONS

A multimodal radiotherapy-containing approach is a well-tolerated component of treatment for patients with osteosarcomas undergoing programed resection, allowing low toxicity rates while maintaining high local control rates.