Prediction of pathologic fracture risk of the femur after combined modality treatment of soft tissue sarcoma of the thigh

What is the incidence and non-union rate of radiation-associated fractures? - A systematic review of the literature

BACKGROUND

Radiation-associated fractures (RAFs) are a challenging complication in oncologic patients, yet their incidence remains unknown and optimal management lacks consensus.

AIM

This review aimed to evaluate the incidence of RAFs in the trunk, pelvis, and extremities as well as non-union rates of surgical and non-surgical treatment.

MATERIALS AND METHODS

A systematic review of PubMed and Embase databases was conducted. The study was registered on PROSPERO (ID: CRD42024513017). Studies were included if they reported RAFs in oncologic populations, had a sample size of at least five patients, and provided extractable data on RAF incidence or number. The STROBE checklist was utilized for evaluation of study quality. For eligible studies, quantitative analyses were conducted to determine weighted incidence of RAF and fracture non-union.

RESULTS

Thirty-five studies comprising 9,980 patients treated with radiation therapy were included. The weighted incidence of RAFs was calculated to be 6.5% across 8,061 patients. The weighted incidence of femoral RAF was 5.2%, while pelvic RAF incidence was 17.1%. Non-union rates after initial treatment varied from 4% to 100%, with an overall weighted incidence of 48%. Treatments included intramedullary nailing, fixation with screws/plate, prosthetic replacement, conservative treatment, and amputation, with varying success rates.

CONCLUSION

This review highlights RAFs as a significant complication of radiation therapy, with a weighted incidence of 6.5% and a non-union rate of 48%. Advanced radiation techniques have reduced RAF occurrences, but non-union remains a challenge, necessitating tailored treatment strategies. Further research is needed to optimize RAF management and improve patient outcomes.

Moderately hypofractionated, preoperative radiotherapy in patients with soft tissue sarcomas (HYPORT-STS): Updated local control, late toxicities, and patient-reported outcomes

BACKGROUND

Moderately hypofractionated, preoperative radiotherapy in patients with soft tissue sarcomas (HYPORT-STS; ClinicalTrials.gov identifier NCT03819985) investigated a radiobiologically equivalent, moderately hypofractionated course of preoperative radiotherapy (RT) 15 × 2.85 Gy in patients with soft tissue sarcoma (STS). Here, the authors report longer term follow-up to update local control and report late toxicities, as well as functional and patient-reported outcomes.

METHODS

HYPORT-STS was a single-center, open-label, single-arm, prospective phase 2 clinical trial that enrolled 120 eligible adult patients with localized STS of the extremities or superficial trunk between 2018 and 2021. Patients received a 3-week course of preoperative RT followed by surgery 4-8 weeks later. End points and follow-up were analyzed from the date of surgery.

RESULTS

The median follow-up was 43 months (interquartile range, 37-52 months), and the 4-year local recurrence-free survival rate was 93%. Overall RT-related late toxicities improved with time from local therapy (p < .001), and few patients had grade ≥2 toxicities (9%; n = 8 of 88) at 2 years. These included: 2% grade ≥2 skin toxicity, 2% fibrosis, 3% lymphedema, and 1% joint stiffness. Four patients (3%) had bone fractures. Both functional outcomes, as measured by the Musculoskeletal Tumor Society Rating Scale (p < .001), and quality of life, as measured by the Functional Assessment of Cancer Therapy-General (p < .001), improved with time from treatment, and both measures were better in follow-up at 2 years compared with baseline.

CONCLUSIONS

Long-term follow up suggests that moderately hypofractionated preoperative RT for patients with STS is safe and effective. Higher grade late toxicities affect a minority of patients. Late toxicities decrease over time, whereas functional outcomes and health-related quality of life seem to improve with more time from combined modality treatment.

Endoprosthetic reconstruction for lower extremity soft tissue sarcomas with bone involvement

BACKGROUND AND OBJECTIVES

Bone resection and endoprosthetic reconstruction (EPR) in the setting of soft tissue sarcoma (STS) management is rare and incurs unique challenges. We aim to report on the surgical and oncological outcomes of this relatively previously undocumented cohort.

METHODS

This is a single-center retrospective review of prospectively collected data for patients who required EPRs following resection of STSs of the lower extremity. Following inclusion criteria, we assessed 29 cases of EPR for primary STS of the lower limb.

RESULTS

The mean age was 54 years (range 18-84). Of the 29 patients, there were 6 total femur, 11 proximal femur, 4 intercalary, and 8 distal femur EPRs. Fourteen of 29 patients (48%) underwent re-operations for surgical complications, with 9 relating to infection (31%). When a matched cohort analysis was performed comparing our cohort to STSs that did not necessitate EPR, a reduced rate of overall survival and metastasis-free survival was found in those requiring EPR.

CONCLUSION

This series identifies a high rate of complication from EPRs performed for STS. Patients should be cautioned about the high rate of infection, surgical complications, and lower overall survival in this setting.

Fracture in Irradiated Rat Femur: A Description of an Experimental Model and Evaluation of its Effectiveness

Objective  We aim to describe an experimental model for studying femoral fractures in rats after exposure to ionizing radiation, demonstrating a way to apply a substance for analysis, the method for patterning fracture and irradiation, and how to evaluate its effectiveness based on radiographic studies. Methods  We used 24 rats divided into 2 groups of 12 animals each. The STUDY group was exposed to ionizing radiation and treated with saline solution, and the CONTROL group was not exposed to radiation and was treated with saline solution. All animals were subjected to standardized fracture of the right femur that was fixed with intramedullary wire. The efficiency of the bone union was assessed by radiographic exam. Results  Fracture healing was more efficient in bones not exposed to ionizing radiation ( p  = 0.012). All fractures met the criteria of being simple, diaphyseal, transverse or short oblique. Conclusion  The experimental model presented is an efficient alternative for the study of fractures in irradiated bones in rats.

Radiation Induces Bone Microenvironment Disruption by Activating the STING-TBK1 Pathway

Background and Objectives: Damage to normal bone tissue following therapeutic irradiation (IR) represents a significant concern, as IR-induced bone microenvironment disruption can cause bone loss and create a more favorable environment for tumor metastases. The aim of the present study was to explore the cellular regulatory mechanism of IR-induced bone microenvironment disruption to effectively prevent radiotherapy-associated adverse effects in the future. Materials and Methods: In this study, a mouse model of local IR was established via local irradiation of the left hind limb of BALB/c mice with 12 Gy X-rays, and an in vitro osteocyte (OCY) model was established by exposing osteocyte-like MLO-Y4 cells to 2, 4, and 8 Gy irradiation to analyze multicellular biological injuries and cellular senescence. Small interfering RNA (siRNA) transfection at the cellular level and a selective antagonist intervention C-176 at the animal level were used to explore the potential role of the stimulator of interferon genes (STING) on IR-induced bone microenvironment disruption. Results: The results showed that 12 Gy local IR induces multicellular dysfunction, manifested as ascension of OCYs exfoliation, activation of osteoclastogenesis, degeneration of osteogenesis and fate conversion of adipogenesis, as well as cellular senescence and altered senescence-associated secretory phenotype (SASP) secretion. Furthermore, the expression of STING was significantly elevated, both in the primary OCYs harvested from locally irradiated mice and in vitro irradiated MLO-Y4 cells, accompanied by the markedly upregulated levels of phosphorylated TANK-binding kinase 1 (P-TBK1), RANKL and sclerostin (SOST). STING-siRNA transfection in vitro restored IR-induced upregulated protein expression of P-TBK1 and RANKL, as well as the mRNA expression levels of inflammatory cytokines, such as IL-1α, IL-6 and NF-κB, accompanied by the alleviation of excessive osteoclastogenesis. Finally, administration of the STING inhibitor C-176 mitigated IR-induced activation of osteoclastogenesis and restraint of osteogenesis, ameliorating the IR-induced biological damage of OCYs, consistent with the inhibition of P-TBK1, RANKL and SOST. Conclusions: The STING-P-TBK1 signaling pathway plays a crucial role in the regulation of the secretion of inflammatory cytokines and osteoclastogenesis potential in IR-induced bone microenvironment disruption. The selective STING antagonist can be used to intervene to block the STING pathway and, thereby, repair IR-induced multicellular biological damage and mitigate the imbalance between osteoclastogenesis and osteoblastgenesis.

Dose-Volume Constraints fOr oRganS At risk In Radiotherapy (CORSAIR): An "All-in-One" Multicenter-Multidisciplinary Practical Summary

BACKGROUND

The safe use of radiotherapy (RT) requires compliance with dose/volume constraints (DVCs) for organs at risk (OaRs). However, the available recommendations are sometimes conflicting and scattered across a number of different documents. Therefore, the aim of this work is to provide, in a single document, practical indications on DVCs for OaRs in external beam RT available in the literature.

MATERIAL AND METHODS

A multidisciplinary team collected bibliographic information on the anatomical definition of OaRs, on the imaging methods needed for their definition, and on DVCs in general and in specific settings (curative RT of Hodgkin's lymphomas, postoperative RT of breast tumors, curative RT of pediatric cancers, stereotactic ablative RT of ventricular arrythmia). The information provided in terms of DVCs was graded based on levels of evidence.

RESULTS

Over 650 papers/documents/websites were examined. The search results, together with the levels of evidence, are presented in tabular form.

CONCLUSIONS

A working tool, based on collected guidelines on DVCs in different settings, is provided to help in daily clinical practice of RT departments. This could be a first step for further optimizations.

Successful Management of Radiation-Associated Insufficiency Fracture of the Tibial Plateau with Low-Intensity Pulsed Ultrasound

Patient: Female, 52-year-old

Final Diagnosis: Fracture

Symptoms: Knee pain

Medication:—

Clinical Procedure: —

Specialty: Oncology

Treatment of Radiation-Associated Fractures: A Critical Analysis Review

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Fractures that result from radiation-induced bone damage are a recognized adverse effect of radiation therapy (RT).

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The mechanisms of damage from RT are thought to be related to impaired vascularity, aberrations in osteoclast and osteoblast-mediated bone turnover, and compromise of cortical and trabecular microarchitecture.

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Treatment of radiation-associated fractures is challenging, with rates of delayed union and nonunion of >50%.

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Fracture management strategies, each with its own profile of risks and benefits, include prophylactic intramedullary nailing of long bones, open reduction and internal fixation with adjunctive iliac crest or vascularized fibular grafting, and endoprosthetic reconstruction.

Femoral fracture in primary soft-tissue sarcoma of the thigh treated with radiation therapy: indications for prophylactic intramedullary nail

INTRODUCTION

Post-radiation fractures of the femur (PRF) are difficult to treat and are associated with a high risk of delayed union and non-union. We report a series of patients affected by soft tissue sarcoma (STS) of the thigh, treated with limb-sparing surgery and perioperative radiotherapy (RT), to analyse post-radiotherapy femur fracture (FF) rate and its management.

MATERIAL AND METHODS

547 patients treated with surgery and RT for a deep primary STS of the thigh were included. "Periosteal stripping" and "bone tangential resection" were performed in case of tumor invasion. In the case of complete bone involvement, the patient received its complete resection and econstruction.

RESULTS

Twenty-three (4.3%) patients underwent surgical procedures involving periosteum and cortical bone. In 11 (2.0%) patients a bone resection was required because of massive bone involvement. Six out of these 11 (54.5%) patients developed major complications (infection and aseptic loosening). At the time of STS excision, 11 patients (2.0%) underwent prophylactic intramedullary nailing (PIN). PRF occurred in 15 patients (3.0%) at a median follow up of 52 months (range 3-151). Among patients who developed PRF, three were treated with a prosthesis (no complications) and eight nailing (7/8, 87.5% did not heal and developed a non-union).

CONCLUSIONS

Given the potentially devastating complication of a PRF, PIN should be considered. We suggest prophylactic IM nail in patients at higher risk the time of STS excision. In other cases, IM nail can be postponed in the following years considering the prognosis.

Pathologic femur fractures following surgery and radiotherapy for soft tissue sarcomas: A case series

Introduction

Combined limb-sparing surgery and radiation therapy are considered the standard of care for higher grade soft tissue sarcomas (STS) of the extremities. The risk of post-radiation fracture after this treatment modality is well known, but still underestimated, and can end in serious long-term secondary problems years later.

Presentation of case

We reviewed the records of three patients with pathological femur fractures years after wide local excision of an STS of the proximal lower extremity. All patients received more than 50 Gy (Gy) to the entire femur circumference. During surgery, all patients had bone exposure, and in two patients with stripping of the periosteum. The median time from surgery to fracture was 116 months (range from 84 to 156 months). The median age at the time of diagnosis was 66 years old. Despite standard operative fracture treatment, all three patients developed a non-union. One patient later died due to uncontrolled pulmonary metastasis independent from the femoral non-union. In the second case, an exarticulation at hip level due to an uncontrolled infected non-union had to be performed. The third patient finally achieved fracture union after two years of treatment.

Discussion

Our study confirms the high occurrence rate of postoperative complications and difficulties one encounters in treating these pathologic fractures. Only in one patient, following several revisions with intramedullary nailing, the fracture healed. In pathologic femur shaft fractures we recommend a minimal invasive procedure using intramedullary nailing devices.

Conclusion

The risk of pathological fractures at the former treatment site is high, even years later. The rate of non-unions after a difficult fracture treatment in this particular clinical situation seems to be very high and may be associated with severe complications.

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3 patients with pathological femur fractures after excision of sarcoma are reviewed.

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Risk of post-radiation fracture after this treatment modality is underestimated.

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Despite standard operative fracture treatment, rate of non-unions is very high.

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We recommend a minimal invasive procedure using intramedullary nailing devices.

Treatment options in femoral radiation fractures following soft tissue sarcoma: Incidence, risk factors, failures and flowchart of treatment

INTRODUCTION

The femur is the most frequent involved site by post-attinic fractures. The appropriate treatment of pathological fractures after radiotherapy is still controversial as they are associated with a high risk of delayed consolidation and non-union. Authors review a single Center series of pathological fractures after radiation therapy in patients affected by soft tissue sarcomas analyzing incidence, risk factors, failure rate and proposing a flow chart of treatment of postattinic fractures of the femur.

METHODS

Authors selected 570 patients treated by limb salvage surgery associated to radiation therapy from 1992 to 2018. A pathological fracture during follow up was observed in 28 cases (5%). The mean time between the onset of the fracture after the prior surgery + radiotherapy was 70 months (range 3-182). The mean follow-up from the fracture was 86 months (range 9-222).

RESULTS

The fracture treatment was performed with an intramedullary nail in 15 cases. Eight femoral fractures healed uneventfully (57%) and 6 required further surgical procedures. A total of eight patients underwent prosthetic replacement, 3 as a primary treatment and 5 as a salvage procedure after failure of internal fixation. Five patients developed a deep infection (62.5%).We observed 10 non-union (53%) in 19 patients treated with osteosynthesis. Overall amputation rate of the entire series was 18%. Authors propose a flowchart of treatment for femoral fractures.

CONCLUSION

Intramedullary nailing is the treatment of choice in postradiation diaphyseal fractures of long bones, prosthetic replacement in meta-epiphyseal fracture site. Free vascularized grafts remain a valid salvage solution after failure of internal fixation.

Pathological fractures of the femur after radiation therapy for soft tissue tumor: a case series of seven patients treated with repeated internal fixation

INTRODUCTION

Pathological femoral fracture (PFF) after radiation therapy (RT) for soft tissue tumor is a debilitating complication with a high rate of nonunion that requires multiple subsequent procedures and hindrance of functional activity. We aimed to evaluate healing rate after repeated internal fixation in a case series of PFF after RT.

MATERIALS AND METHODS

We retrospectively reviewed the records of patients who had PFF after RT and were treated at our center between 2007 and 2018. We analyzed our surgical protocols and fracture healing rate.

INTERPRETATION

We identified and analyzed a total of seven patients (six females and one male) whose mean age at fracture was 58 years. Primary tumors consisted of soft tissue sarcoma (n = 5), melanoma (n = 1), and desmoid tumor (n = 1). All primary tumors were treated with surgical excision and adjuvant RT. The mean follow-up duration after fracture was 33 months (range, 16-58). At the last follow-up, five out of seven fractures had completely healed, and two lesions showed delayed union at 15 and 16 months, respectively. Among the five complete unions, one fracture was healed after the first fixation. The remaining four lesions were treated with second internal fixation due to nonunion/metal failure or delayed union. The mean time to radiologic healing after the last fixation was 6.8 months (range, 5-8).

CONCLUSIONS

Our results suggest that bones within the RT field retain healing capacities, and that repeated internal fixation may be a viable option for the treatment of PFF after RT.

Altered mechanical behavior of demineralized bone following therapeutic radiation

Post-radiotherapy (RTx) bone fragility fractures are a late-onset complication occurring in bone within or underlying the radiation field. These fractures are difficult to predict, as patients do not present with local osteopenia. Using a murine hindlimb RTx model, we previously documented decreased mineralized bone strength and fracture toughness, but alterations in material properties of the organic bone matrix are largely unknown. In this study, 4 days of fractionated hindlimb irradiation (4 × 5 Gy) or Sham irradiation was administered in a mouse model (BALB/cJ, end points: 0, 4, 8, and 12 weeks, n = 15/group/end point). Following demineralization, the viscoelastic stress relaxation, and monotonic tensile mechanical properties of tibiae were determined. Irradiated tibiae demonstrated an immediate (day after last radiation fraction) and sustained (4, 8, 12 weeks) increase in stress relaxation compared to the Sham group, with a 4.4% decrease in equilibrium stress (p < .017). While tensile strength was not different between groups, irradiated tibiae had a lower elastic modulus (-5%, p = .027) and energy to failure (-12.2%, p = .012) with monotonic loading. Gel electrophoresis showed that therapeutic irradiation (4 × 5 Gy) does not result in collagen fragmentation, while irradiation at a common sterilization dose (25 kGy) extensively fragmented collagen. These results suggest that altered collagen mechanical behavior has a role in postirradiation bone fragility, but this can occur without detectable collagen fragmentation. Statement of Clinical Significance: Therapeutic irradiation alters bone organic matrix mechanics and which contribute to diminished fatigue strength, but this does not occur via collagen fragmentation.

Postradiation Fractures after Combined Modality Treatment in Extremity Soft Tissue Sarcomas

Soft tissue sarcoma (STS) of the extremities is typically treated with limb-sparing surgery and radiation therapy; with this treatment approach, high local control rates can be achieved. However, postradiation bone fractures, fractures occurring in the prior radiation field with minimal or no trauma, are a serious late complication that occurs in 2–22% of patients who receive surgery and radiation for STS. Multiple risk factors for sustaining a postradiation fracture exist, including high radiation dose, female sex, periosteal stripping, older age, femur location, and chemotherapy administration. The treatment of these pathological fractures can be difficult, with complications including delayed union, nonunion, and infection posing particular challenges. Here, we review the mechanisms, risk factors, and treatment challenges associated with postradiation fractures in STS patients.

Intraoperative radiation therapy (IORT) for soft tissue sarcoma - ESTRO IORT Task Force/ACROP recommendations

PURPOSE

To describe guidelines for the use of intraoperative radiation therapy (IORT) in the treatment of soft-tissue sarcomas (STS).

METHODS

A panel of experts in the field performed a systematic literature review, supplemented their clinical experience and developed recommendations for the use of IORT in the treatment of STS.

RESULTS

Based on the evidence from the systematic literature review and the clinical experience of the panel members, recommendations regarding patient selection, incorporation into multimodal treatment concepts and the IORT procedure itself are made. The rationale for IORT in extremity and retroperitoneal STS is summarized and results of the major series in terms of patient and treatment characteristics, oncological outcome and toxicity are presented. We define surgical factors, volumes for irradiation, technical requirements, dose prescription, recording and reporting, treatment delivery and care during the course of IORT covering the main IORT techniques used for the treatment of STS. In extremity STS, evidence originates from a few small prospective and mainly from retrospective single centre studies. Based on those reports, IORT containing-approaches result in very high local control rates with low rates of acute and late toxicity. In retroperitoneal sarcomas, evidence is derived from one prospective randomized trial, a few prospective and a large number of retrospective studies. The randomized trial compared IORT combined with moderate doses of postoperative external-beam radiation therapy (EBRT) to high-dose postoperative EBRT alone after gross total resection, clearly favouring the IORT-containing approach. These results have been confirmed by the prospective and retrospective studies, which similarly showed high local control rates with acceptable toxicity, mainly favouring combinations of preoperative EBRT and IORT.

CONCLUSIONS

IORT-containing approaches result in high rates of local control with low to acceptable toxicity rates. Based on the available evidence, we made recommendations for the use of IORT in STS. Clinicians and researchers are encouraged to use these guidelines in clinical routine as well as in the design of future trials.

Pathological fracture after radiotherapy: systematic review of literature

OBJECTIVE

To evaluate the epidemiological data and available treatments for fractures secondary to radiotherapy treatment.

METHODS

Identification of publications on pathological skeletal fractures previously exposed to ionizing radiation.

RESULTS

The incidence of fractures after irradiation varies from 1.2% to 25% with a consolidation rate of 33% to 75%, being more frequent in the ribs, pelvis, and femur. The time elapsed between irradiation and fracture occurs years after radiotherapy. Risk factors include age above 50 years, female gender, extensive periosteal detachment, circumferential irradiation, tumor size, and anterior thigh location. The etiology is still uncertain, but cellular disappearance, reduction of bone turnover and activity were observed hematopoietic as possible causes of failure of consolidation.

CONCLUSION

There is no consensus in the literature on the factors related to the development of fractures, with radiation dose, previous tumor size and periosteal detachment being suggested as potential factors.

Femoral Fracture in Primary Soft-Tissue Sarcoma of the Thigh and Groin Treated with Intensity-Modulated Radiation Therapy: Observed versus Expected Risk

PURPOSE

This study was designed to compare the observed risk of femoral fracture in primary soft-tissue sarcoma (STS) of the thigh/groin treated with intensity-modulated radiation therapy (IMRT) to expected risk calculated using the Princess Margaret Hospital (PMH) nomogram.

METHODS

Expected femoral fracture risk was calculated by using the PMH nomogram. Cumulative risk of fracture was estimated by using Kaplan-Meier statistics. Prognostic factors were assessed with univariate and multivariate analysis using Cox's stepwise regression.

RESULTS

Between February 2002 and December 2010, 92 consecutive eligible patients were assessed. Median follow-up was 73 months (106 months in surviving patients). IMRT was delivered preoperatively (50 Gy) in 13 (14%) patients and postoperatively in 79 (86%) patients (median dose, 63 Gy; range, 59.4-66.6 Gy). The observed crude risk of fractures was 6.5% compared with 25.6% expected risk from the nomogram; the cumulative risk of fracture using IMRT at 5 years was 6.7% (95% CI 2.8-16.0%). The median time to fracture was 23 months (range, 6.9-88.6). Significant predictors of fracture on univariate analysis were age ≥ 60 years (p = 0.03), tumor location in the anterior thigh (p = 0.008), and periosteal stripping to > 20 cm (p < 0.0001). On multivariate analysis, age ≥ 60 years and periosteal stripping > 20 cm retained significance (p = 0.04 and p = 0.009, respectively).

CONCLUSIONS

In this study, the cumulative risk of femur fracture in patients treated with IMRT (6.7%) is less than the expected risk using the PMH nomogram (25.6%). Established predictors of femur fracture, such as gender, tumor size, and dose of RT, seem to have less impact on fracture risk when using IMRT.

Amifostine Suppresses the Side Effects of Radiation on BMSCs by Promoting Cell Proliferation and Reducing ROS Production

This study is aimed at investigating the effect of amifostine (AMI) on rat bone marrow stromal stem cells (BMSCs) exposed to 2 Gy radiation. The BMSCs were divided into four groups, namely, group A that received 0 Gy radiation, group B that received 0 Gy radiation and AMI, group C that received 2 Gy radiation, and group D that received 2 Gy radiation and AMI. The proliferation, apoptosis, and distribution of BMSCs in the cell cycle, along with their osteogenesis ability, adipogenesis ability, and ROS production, were subsequently examined. The levels of ALP, PPARγ, P53, and TNFα were determined by Western blotting. The results demonstrated that the proliferation of BMSCs and the levels of ALP in group C were much lower than those in group A. The production of ROS and levels of PPARγ, P53, and TNFα in the group that received 2 Gy radiation were much higher than those in group A. Furthermore, the production of ROS and the levels of PPARγ, P53, and TNFα were much lower in group D than in group C. Additionally, the levels of ALP and extent of cell proliferation were much higher in group D than in group C. The results demonstrated the potential of AMI in reducing the side effects of radiation in BMSCs and in treatment of bone diseases caused by radiation.

Limited field radiation therapy results in decreased bone fracture toughness in a murine model

Fragility fractures are a well-known complication following oncologic radiotherapy, and it is suspected that radiation-induced embrittlement of bone within the treatment field may contribute to fracture risk. To explore this phenomenon, a mouse model (BALB/cJ) of fractionated, limited field, bilateral hindlimb irradiation (4x5 Gy) was used. The effects of radiation on femoral (cortical) bone fracture toughness, morphology, and biochemistry-including advanced glycation end products (AGEs)-were quantified and compared to Sham group samples prior to irradiation and at 0, 4, 8, and 12 weeks post-irradiation. Additionally, alterations to bone fracture toughness mediated directly by radiation (independent of cellular mechanisms) were determined using devitalized mouse cadaver femurs. Finally, the contribution of AGEs to reduced fracture toughness was examined by artificially ribosylating mouse femurs ex vivo. These data demonstrate that in vivo irradiation results in an immediate (-42% at 0 weeks, p < 0.001) and sustained (-28% at 12 weeks, p < 0.001) decrease in fracture toughness with small changes in morphology (-5% in cortical area at 12 weeks), and minimal changes in bone composition (tissue mineral density, mineral:matrix ratio, and AGE content). Irradiation of devitalized femurs also reduced fracture toughness (-29%, p < 0.001), but to a lesser extent than was seen in vivo. While artificial ribosylation decreased fracture toughness with time, the extent of glycation needed to induce this effect exceeded the AGE accumulation that occurred in vivo. Overall, hindlimb irradiation induced a substantial and sustained decrease in bone fracture toughness. Approximately half of this decrease in fracture toughness is due to direct radiation damage, independent of cellular remodeling. Collagen glycation in vivo was not substantially altered, suggesting other matrix changes may contribute to post-radiotherapy bone embrittlement.

Fractures after multimodality treatment of soft tissue sarcomas with isolated limb perfusion and radiation; likely to occur and hard to heal

OBJECTIVES

Treatment associated fractures (TAFs) are known severe side effects after surgery and radiotherapy for soft tissue sarcoma (STS). There is no literature about TAF after multimodality treatment with isolated limb perfusion (ILP) for locally advanced STS. This study aimed to analyze predictive factors, treatment and outcome for TAF after multimodality treatment with ILP.

METHOD

Out of 126 consecutive patients undergoing ILP after 1991 till now, 25 patients were excluded due to no surgery or direct amputation at initial surgery. Therefore, 101 patients were at risk and 12 developed a TAF (12%).

RESULTS

The majority of tumors was located at the upper leg and knee (N = 60), and 11 patients developed a TAF (18%) after median 28 (5-237) months. Twenty-five tumors were located at the lower leg, and 1 patient developed a TAF after 12 months (4%). No patients with a tumor at the upper extremities (N = 16) developed a TAF. Ten out of 12 patients with a fracture received adjuvant RT with a dose of 50 Gy, and a median boost dose of 18 (10-20) Gy. Predictive factors were periosteal stripping, age over 65 years at time of treatment and tumor size after ILP ≥10 cm. Multivariate analysis showed periosteal stripping and tumor size after ILP ≥10 cm as significant predictive factors. The majority of the fractures were treated with intramedullary nailing. Only one of 12 patients without radiotherapy reached bone union (8%). The median survival after developing TAF was 18 (1-195) months.

CONCLUSION

The overall risk of TAF after multimodality treatment with ILP was relatively high with 15% at ten years. The incidence of TAF for patients with tumors located at the thigh and knee after resection with periosteal stripping and radiotherapy was even >50%. The treatment of these fractures is challenging due to the high non-union rate, requiring an extensive orthopedic oncological TAF experience.

Management of soft-tissue sarcomas; treatment strategies, staging, and outcomes

Soft-tissue sarcomas (STS) are a rare group of malignant tumors which can affect any age group. For the majority of patients who present with a localized STS, treatment involves a multidisciplinary team decision-making approach ultimately relying on surgical resection with or without adjuvant radiation for successful limb salvage. The goals of treatment are to provide the patient with a functional extremity without local tumor relapse. The purpose of this article is to review the treatment of extremity STS, with a focus on staging, treatment options, and outcomes.

External-beam radiation therapy combined with limb-sparing surgery in elderly patients (>70 years) with primary soft tissue sarcomas of the extremities : A retrospective analysis

PURPOSE

To report our experience with EBRT combined with limb-sparing surgery in elderly patients (>70 years) with primary extremity soft tissue sarcomas (STS).

METHODS

Retrospectively analyzed were 35 patients (m:f 18:17, median 78 years) who all presented in primary situation without nodal/distant metastases (Charlson score 0/1 in 18 patients; ≥2 in 17 patients). Median tumor size was 10 cm, mainly located in lower limb (83%). Stage at presentation (UICC7th) was Ib:3%, 2a:20%, 2b:20%, and 3:57%. Most lesions were high grade (97%), predominantly leiomyosarcoma (26%) and undifferentiated pleomorphic/malignant fibrous histiocytoma (23%). Limb-sparing surgery was preceded (median 50 Gy) or followed (median 66 Gy) by EBRT.

RESULTS

Median follow-up was 37 months (range 1-128 months). Margins were free in 26 patients (74%) and microscopically positive in 9 (26%). Actuarial 3‑ and 5‑year local control rates were 88 and 81% (4 local recurrences). Corresponding rates for distant control, disease-specific survival, and overall survival were 57/52%, 76/60%, and 72/41%. The 30-day mortality was 0%. Severe postoperative complications were scored in 8 patients (23%). Severe acute radiation-related toxicity was observed in 2 patients (6%). Patients with Charlson score ≥2 had a significantly increased risk for severe postoperative complications and acute radiation-related side effects. Severe late toxicities were found in 7 patients (20%), including fractures in 3 (8.6%). Final limb preservation rate was 97%.

CONCLUSION

Combination of EBRT and limb-sparing surgery is feasible in elderly patients with acceptable toxicities and encouraging but slightly inferior outcome compared to younger patients. Comorbidity correlated with postoperative complications and acute toxicities. Late fracture risk seems slightly increased.

Carbon fiber intramedullary nails reduce artifact in postoperative advanced imaging

OBJECTIVE

This study assessed whether radiolucent carbon fiber reinforced-polyetheretherketone (CFR-PEEK) intramedullary nails decreased hardware artifact on magnetic resonance imaging (MRI) and computed tomography (CT) in vitro and in an oncologic patient population.

MATERIALS AND METHODS

In vitro and clinical evaluations were done. A qualitative assessment of metal artifact was performed using CFR-PEEK and titanium nail MRI phantoms. Eight patients with a femoral or tibial prophylactic CFR-PEEK nail were retrospectively identified. All patients had postoperative surveillance imaging by MRI, CT, and were followed for a median 20 months (range, 12-28 months). CFR-PEEK images were compared to images from a comparative group of patients with titanium femoral intramedullary nails who had a postoperative MRI or CT. A musculoskeletal-trained radiologist graded visualization of the cortex, corticomedullary junction, and bone-muscle interface, on T1-weighted (T1W), STIR, and contrast-enhanced T1-weighted fat-saturated (T1W FS) sequences of both groups with a five-point scale, performing independent reviews 4 months apart. Statistical analysis used the Wilcoxon rank-sum test and a weighted kappa.

RESULTS

Substantially less MRI signal loss occurred in the CFR-PEEK phantom than in the titanium phantom simulation, particularly as the angle increased with respect to direction of the static magnetic field. CFR-PEEK nails had less MRI artifact than titanium nails on scored T1W, STIR, and contrast-enhanced T1W FS MRI sequences (p ≤ 0.03). The mean weighted kappa was 0.64, showing excellent intraobserver reliability between readings.

CONCLUSIONS

CFR-PEEK intramedullary nail fixation is a superior alternative to minimize implant artifact on MRI or CT imaging for patients requiring long bone fixation.

[Insufficiency fractures after irradiation therapy - case series]

BACKGROUND

Radiation therapy plays an essential part in modern treatment regimes of musculoskeletal tumors. Nevertheless damage to the surrounding tissue does occur inevitably. Postradiogenic changes of bone are associated with decreased stability and an increased fracture rate. The orthopedic surgeon therefore faces a challenging situation with altered bone metabolism, changes in perfusion and soft tissue problems.

PATIENTS/MATERIAL AND METHODS

We present 3 cases of radiation induced fractures during the treatment of soft tissue tumors, all of which received radiation doses of > 58 Gy. All fractures occurred over 1 year after the exposure to radiation in otherwise uneventful follow ups.

RESULTS

Postoperative follow up showed fracture healing or in the case of the arthroplasty, osseous integration without further complications.

CONCLUSIONS

Radiation doses of ≥ 58 Gy are a major risk factor for pathological fractures in long bones. Regardless of their low incidence, fracture rates between 1,2 and 6,4 % prove their importance. Local tumor control has therefore to be weighed against the resulting decrease in bone quality and stability. Treatment options should always take into consideration the increased risk for complications such as infection, pseudarthroses and wound healing disorders. Our results show that substitution of vitamin D and calcium as well as the the use of reamed intramedullary implants benefits the outcome.

Can OP-1 stimulate union in a rat model of pathological fracture post treatment for soft tissue sarcoma?

The goal of soft tissue sarcoma management in the extremities is limb preservation, often combining surgery and external beam radiation. In patients who have undergone this therapy in the thigh, pathologic fracture is a serious, late complication. Non-union rates of 80-90% persist. No reliable biologic solution exists. A rat model combining one 18 Gy dose of radiation and diaphyseal periosteal excision reliably generates atrophic non-union of femoral fractures. We hypothesized that augmentation with OP-1 would increase union rate. Female Sprague-Dawley retired breeder rats were randomized to Control, Disease (external beam radiotherapy and periosteal stripping), Control + OP-1 (80 µg) and Disease + OP-1 groups. Animals underwent prophylactic fixation and controlled left femur fracture. Twenty-eight, 35, and 42 days post-fracture were end-points. Femora were analyzed using MicroCT, Back Scattered Electron Microscopy, and Histomorphometry. We observed a 2% union rate in the Disease groups (±OP-1 treatment). The union rate in Control groups was 97%. MicroCT demonstrated a lack of callus volume in Disease groups. Heterotopic ossification was observed in some OP-1 treated animals. The ineffectiveness of OP-1 in stimulating fracture union in this model suggests the endogenous repair mechanism has been compromised beyond the capabilities of osteoinductive biologics.

Excellent local control with IOERT and postoperative EBRT in high grade extremity sarcoma: results from a subgroup analysis of a prospective trial

Background

To report the results of a subgroup analysis of a prospective phase II trial focussing on radiation therapy and outcome in patients with extremity soft tissue sarcomas (STS).

Methods

Between 2005 and 2010, 50 patients (pts) with high risk STS (size ≥ 5 cm, deep/extracompartimental location, grade II-III (FNCLCC)) were enrolled. The protocol comprised 4 cycles of neoadjuvant chemotherapy with EIA (etoposide, ifosfamide and doxorubicin), definitive surgery with IOERT, postoperative EBRT and 4 adjuvant cycles of EIA. 34 pts, who suffered from extremity tumors and received radiation therapy after limb-sparing surgery, formed the basis of this subgroup analysis.

Results

Median follow-up from inclusion was 48 months in survivors. Margin status was R0 in 30 pts (88%) and R1 in 4 pts (12%). IOERT was performed as planned in 31 pts (91%) with a median dose of 15 Gy, a median electron energy of 6 MeV and a median cone size of 9 cm. All patients received postoperative EBRT with a median dose of 46 Gy after IOERT or 60 Gy without IOERT. Median time from surgery to EBRT and median EBRT duration was 36 days, respectively. One patient developed a local recurrence while 11 patients showed nodal or distant failures. The estimated 5-year rates of local control, distant control and overall survival were 97%, 66% and 79%, respectively. Postoperative wound complications were found in 7 pts (20%), resulting in delayed EBRT (>60 day interval) in 3 pts. Acute radiation toxicity mainly consisted of radiation dermatitis (grade II: 24%, no grade III reactions). 4 pts developed grade I/II radiation recall dermatitis during adjuvant chemotherapy, which resolved during the following cycles. Severe late toxicity was observed in 6 pts (18%). Long-term limb preservation was achieved in 32 pts (94%) with good functional outcome in 81%.

Conclusion

Multimodal therapy including IOERT and postoperative EBRT resulted in excellent local control and good overall survival in patients with high risk STS of the extremities with acceptable acute and late radiation side effects. Limb preservation with good functional outcome was achieved in the majority of patients.

Trial registration

ClinicalTrials.gov NCT01382030, EudraCT 2004-002501-72, 17.06.2011

Efficacy of adjuvant radiation therapy in the treatment of soft tissue sarcoma of the extremity: 20-year follow-up of a randomized prospective trial

BACKGROUND

This update of a randomized, prospective study presents the effect of external beam radiation therapy (EBRT) on long-term overall survival, local control, and limb function following limb-sparing surgery (LSS) for the treatment extremity soft tissue sarcoma (STS).

METHODS

Following LSS, patients with extremity STS were randomized to receive EBRT or surgery alone. All patients with high-grade STS received adjuvant chemotherapy. Long-term follow-up was obtained through telephone interviews using a questionnaire based on validated methods. Overall survival (OS) was determined by Kaplan-Meier method.

RESULTS

A total of 141 patients with extremity STS were randomized to receive adjuvant EBRT (n = 70) or LSS alone (n = 71). Median follow-up was 17.9 years. The 10- and 20-year survival was 77 % (95 % CI 66-85 %) and 64 % (95 % CI 52-75 %) for patients receiving LSS alone and 82 % (95 % CI 72-90 %) and 71 % (95 % CI 59-81 %) for patients receiving EBRT (p = 0.22). Of the 54 patients who completed telephone interviews, the incidence of local recurrence during the follow-up period was 4 % (1 of 24) in the LSS alone cohort compared with 0 % (0 of 30) in those who received EBRT (p = 0.44). Patients treated with EBRT tended to have more wound complications (17 vs. 12.5 %, p = 0.72), clinically significant edema (25 vs. 12 %, p = 0.31), and functional limb deficits (15 vs. 12 %, p = 0.84).

CONCLUSIONS

Adjuvant EBRT following surgery for STS of the extremity provides excellent local control with acceptable treatment-related morbidity and no statistically significant improvement in overall survival.

Raman spectroscopy demonstrates prolonged alteration of bone chemical composition following extremity localized irradiation

INTRODUCTION

Radiotherapy to the appendicular skeleton can cause an increased risk of developing catastrophic fractures with delayed bone healing or non-union, and may subsequently require multiple procedures and amputation. Biomechanical studies suggest that irradiated bone is more brittle, but the cause is unclear and cannot be explained by changes to bone structure or quantity, suggesting that there are crucial changes in irradiated bone material properties. Raman spectroscopy provides a means to assess the chemical properties of the mineral and matrix constituents of bone, which could help explain post-radiation embrittlement. In this study we use a murine tibial model with focal irradiation and perform Raman spectroscopy to test the hypothesis that changes in bone chemistry following irradiation is consistent with reduced bone quality and persists in the long term after irradiation.

METHODS

Female BALB/F mice aged 12weeks were subjected to unilateral, localized hindlimb irradiation in 4 daily 5Gy fractions (4×5Gy) totaling 20Gy, and were euthanized at 1, 4, 8, 12, and 26weeks post-irradiation (n=6/group). The irradiated (right) and non-irradiated contralateral control (left) tibiae were explanted and assessed by non-polarized and polarized Raman spectroscopy over the proximal cortical bone surface. Raman parameters used included the mineral/matrix ratio, mineral crystallinity, carbonate/phosphate ratio, collagen cross-link ratio, and depolarization ratio.

RESULTS

Significantly increased collagen cross-link ratio and decreased depolarization ratio of matrix were evident at 1week after irradiation and this persisted through 26weeks. A similar significant decrease was observed for depolarization ratio of mineral at all time points except 8 and 26weeks. At 4weeks after irradiation there was a significantly increased mineral/matrix ratio, increased mineral crystallinity, and decreased carbonate/phosphate ratio compared to controls. However, at 12weeks after irradiation these parameters had moved in the opposite direction, resulting in a significantly decreased mineral/matrix ratio, decreased crystallinity and increased carbonate/phosphate ratio compared to controls. At 26weeks, mineral/matrix, crystallinity and carbonate/phosphate ratios had returned to normal.

DISCUSSION

In this mouse model, Raman spectroscopy reports both bone mineral and collagen cross-link radiation-induced abnormalities that are evident as early as one week after irradiation and persists for 26weeks. The picture is one of extensive damage, after which there is an attempt at remodeling. We hypothesize that pathological cross-links formed by radiation damage to collagen are poorly resorbed during the altered remodeling process, so that new tissue is formed on a defective scaffold, resulting in increased bone brittleness.

Effects of radiation and surgery on healing of femoral fractures in a rat model

Management of soft tissue sarcoma involves multimodality treatment, including surgery and radiotherapy. Pathologic fracture of the femur after such treatment in the thigh is one serious, late complication and nonunion rates of 80-90% are reported. We hypothesize that the combination of radiotherapy and periosteal stripping (during tumor resection) leads to greater impairment of the fracture repair process than either intervention alone. Female Wistar retired breeder rats were randomized into four treatment groups (control, radiotherapy, surgery, and combination of radiotherapy and surgery) and three end-points (21, 28, and 35 days post-fracture). Designated animals first underwent radiotherapy, followed by surgical stripping of the periosteum 3 weeks later and femoral fracture with fixation after another 3 weeks. Animals were sacrificed and fractures examined using microCT and histomorphometry. Simple transverse or short oblique femoral fractures were produced. By 35 days, control animals formed unions, periosteum-stripped animals formed hypertrophic non-unions and irradiated animals formed atrophic non-unions. Histomorphometry revealed an absence of chondroid and osteoid production in animals undergoing radiotherapy. The relative contribution of periosteal stripping to occurrence of non-union was statistically insignificant. Radiation prior to fracture reliably resulted in atrophic non-union in our model. The contribution of periosteal stripping was negligible.

A subtrochanteric femoral fracture 15 years after radiotherapy: a case report

Pathological fracture is a rare but serious complication of radiotherapy. We report on a 44-year-old man who presented with a subtrochanteric femoral fracture 15 years after radiotherapy for a soft-tissue sarcoma in the thigh. We discuss its potential causes, a scoring system to identify high-risk patients for prophylactic intramedullary nailing of the femur, and radiographic signs to identify an impending insufficiency fracture.

Internal fixation of radiation-induced pathological fractures of the femur has a high rate of failure

We investigated the clinical outcome of internal fixation for pathological fracture of the femur after primary excision of a soft-tissue sarcoma that had been treated with adjuvant radiotherapy.

A review of our database identified 22 radiation-induced fractures of the femur in 22 patients (seven men, 15 women). We noted the mechanism of injury, fracture pattern and any complications after internal fixation, including nonunion, hardware failure, secondary fracture or deep infection.

The mean age of the patients at primary excision of the tumour was 58.3 years (39 to 86). The mean time from primary excision to fracture was 73.2 months (2 to 195). The mean follow-up after fracture fixation was 65.9 months (12 to 205). Complications occurred in 19 patients (86%). Nonunion developed in 18 patients (82%), of whom 11 had a radiological nonunion at 12 months, five a nonunion and hardware failure and two an infected nonunion. One patient developed a second radiation-associated fracture of the femur after internal fixation and union of the initial fracture. A total of 13 patients (59%) underwent 24 revision operations.

Internal fixation of a pathological fracture of the femur after radiotherapy for a soft-tissue sarcoma has an extremely high rate of complication and requires specialist attention.

Cite this article: Bone Joint J 2013;95-B:1144–8.

Volume changes in soft tissue sarcomas during preoperative radiotherapy of extremities evaluated using cone-beam CT

Objective

The objective of this study is to quantify volume changes in the gross target volume (GTV) during preoperative radiotherapy for extremity soft tissue sarcomas (ESTS).

Methods

Twenty-seven patients with ESTS, treated with preoperative radiotherapy, were included in this study. Weekly cone-beam CT scans acquired for setup correction were used for GTV delineation in order to quantify volume changes over the course of treatment. Age, anatomical location, tumour type and tumour volume were evaluated as predictive factors for volume changes. Finally, the optimal time point for adaptive intervention was quantified.

Results

A GTV increase to a maximum of 28 % occurred in five patients. Thirteen patients showed no change and nine patients (all diagnosed with myxoid liposarcoma (MLS)) showed a GTV decrease to a maximum of 57 % of the GTV volume at start of treatment. In the multivariate analysis, only the relative volume change for tumour type was significant (p = 0.001). The optimal time point for adaptive intervention in non-MLS patients was the first week and for MLS patients the third week.

Conclusions

Volume changes were quantified during preoperative RT of ESTS. Volume decrease was observed only in MLS patients. Individualised treatment resulting in plan adaptations could result in a clinically useful volume reduction for MLS patients.

Side effects of radiation in musculoskeletal oncology: clinical evaluation of radiation-induced fractures

Radiation therapy and chemotherapy, while they remain an essential part of the multidisciplinary treatment of cancers, they have led to unwanted complications. Radiation-induced complications include wound and bone, growth, nervous system, tumorigenic, lung, gastrointestinal, hepatic and other complications. In this article we review the side effects of radiation therapy in musculoskeletal oncology emphasizing on bone, present our long experience, and discuss the current literature regarding radiation-induced bone complications and their management and outcome.

Site-dependent replacement or internal fixation for postradiation femur fractures after soft tissue sarcoma resection

BACKGROUND

High-dose radiation retards bone healing, compromising the surgical results of radiation-induced fractures. Prosthetic replacement has traditionally been reserved as a salvage option but may best achieve the clinical goals of eliminating pain, restoring function and avoiding complications.

QUESTIONS/PURPOSES

We asked whether patients undergoing prosthetic replacement at index surgery for radiation-related subtrochanteric or diaphyseal fractures of the femur had fewer complications than those undergoing open reduction internal fixation at index operation.

METHODS

We retrospectively reviewed records from 1045 patients with soft tissue sarcomas treated with surgical resection and high-dose radiation therapy between 1982 and 2009 and identified 37 patients with 39 fractures. We recorded patient demographics, diagnosis, type of surgical resection, total radiation dose, fracture location and pattern, years after radiation the fracture occurred, type of surgical fixation, and associated complications.

RESULTS

Patients undergoing prosthetic replacement at index surgery had a lower number of major complications and revision surgeries than those undergoing index open reduction internal fixation. Patients undergoing open reduction internal fixation at index surgery had a nonunion rate of 63% (19 of 30). Fractures located in the metaphysis were more likely to heal than those located in the subtrochanteric or diaphyseal regions.

CONCLUSIONS

Radiation-induced fractures have poor healing potential. Our data suggest an aggressive approach to fracture treatment with a prosthetic replacement can minimize complications and the need for revision surgery.

Bone density changes after radiation for extremity sarcomas: exploring the etiology of pathologic fractures

PURPOSE

The incidental irradiation (RT) of adjacent bone that takes place during treatment of soft tissue extremity sarcomas is generally presumed to "weaken" the bone by decreasing its density, which subsequently increases the risk for pathologic fracture. This investigation intended to assess the relative effects on bone density of both RT and diminished mechanical loading secondary to tumor-induced and therapy-induced functional extremity impairment.

METHODS AND MATERIALS

19 patients treated with surgical excision and RT for soft tissue extremity sarcomas had bone density measured using dual energy X-ray absorptiometry at four sites: the irradiated (A) and contralateral (B) bone, and an uninvolved bone (C) in the treated extremity and its contralateral counterpart (D). Analysis included (1) [A-B], (2) [C-D], (3) [(A-B), - (C-D)], and (4) [(A-B)/B - (C-D)/D].

RESULTS

The mean bone density for all irradiated sites was increased 0.08 ± 0.22 g/cm(2) (variance) compared to the contralateral unirradiated side when corrected for weight-bearing effects (3). An average increase in bone density of 9 ± 22% (p = 0.08) was also seen when the differences were divided by individual control densities to normalize variation in density of different anatomic sites (4).

CONCLUSIONS

RT does not routinely decrease bone density when corrected for weight bearing or mechanical effects. The pathogenesis for the known increased risk of pathologic fracture in irradiated bones is likely multifactorial, including possible alterations in bone remodeling that can result in stable, or even increased, bone density. Further clinical and basic studies are needed to confirm our unexpected findings.