Does Microwave Ablation of the Tumor Edge Allow for Joint-sparing Surgery in Patients With Osteosarcoma of the Proximal Tibia?

Update on Percutaneous Ablation for Sarcoma

PURPOSE OF REVIEW

To provide an update on the current state of percutaneous thermal ablation in the treatment of sarcoma.

RECENT FINDINGS

Data continue to accrue in support of ablation for local control and palliation of specific sarcoma subtypes such as extra-abdominal desmoid fibromatosis and for broader indications such as the treatment of oligometastatic disease. The synergistic possibilities of various combination therapies such as cryoablation and immunotherapy represent intriguing areas of active investigation. Histotripsy is an emerging non-invasive, non-thermal ablative modality that may further expand the therapeutic arsenal for sarcoma treatment. Percutaneous thermal ablation is a valuable tool in the multidisciplinary management of sarcoma, offering a minimally invasive adjunct to surgery and radiation therapy. Although there remains a paucity of high-level evidence specific to sarcomas, ablation techniques are demonstrably safe and effective for achieving local tumor control and providing pain relief in select patients and are of particular benefit in those with metastatic disease or requiring palliative care.

Microwave-assisted intralesional curettage combined with other adjuvant methods for treatment of Campanacci III giant cell tumor of bone in distal radius: a multicenter clinical study

Objective

To compare the clinical outcomes of microwave-assisted intralesional curettage(MAIC) with those of en bloc resection and autogenous fibular reconstruction (EBR-AFR) for treating grade III giant cell tumor of the bone (GCTB) of the distal radius and to elucidate the indications for wrist preservation surgery.

Materials and methods

In this retrospective study, 19 patients with grade III GCTB of the distal radius who underwent surgery at three medical institutions were included and categorized based on their surgical pattern. Seven patients underwent MAIC and internal fixation with bone cement (MAIC group) and 12 underwent EBR-AFR (EBR-AFR group). To evaluate the function of the affected limb postoperatively, wrist range of motion, grip strength, Musculoskeletal Tumor Society (MSTS) scores were recorded.

Results

The follow-up time of the MAIC group was 73.57 ± 28.61 (36-116) months, with no recurrence or lung metastasis. In contrast, the follow-up time of the EBR-AFR group was 55.67 ± 28.74 (36-132) months, with 1 case of local recurrence (8.3%, 1/12) and 1 case of lung metastasis (8.3%, 1/12). The wrist flexion, extension, supination, pronation, grip strength were better in the MAIC group than in the EBR-AFR group. Although there was no statistically significant difference in the MSTS score between the two groups, it is noteworthy that the MAIC group exhibited significantly superior emotional acceptance and hand positioning compared to the EBR-AFR group(p < 0.05).

Conclusion

The functional outcomes of the MAIC group are better. The treatment strategy for grade III GCTB of the distal radius should be determined based on the specific preoperative imaging findings. Nevertheless, MAIC can be the preferred surgical approach for most patients with grade III GCTB of the distal radius, particularly for young patients.

Combination of CT-Guided Microwave Ablation and Cementoplasty as a Minimally Invasive Limb-Sparing Approach in a Dog with Appendicular Osteosarcoma

Image-guided microwave ablation and cementoplasty are minimally invasive techniques that have been used as part of a limb-sparing approach in the treatment of appendicular bone tumors in humans. The objective of this case report was to describe the feasibility and result of microwave ablation (MWA) and cementoplasty in a dog with stage-1 osteoblastic appendicular osteosarcoma of the right distal radius. A microwave antenna was inserted in the osteolytic area using computed tomography (CT) guidance. Three ablation cycles of 5 min at 60 watts were performed. Immediately after the MWA procedure, a tricalcium phosphate-based cement was injected through the bone trocar to consolidate the ablated zone. Adjuvant chemotherapy with six sessions of carboplatin was performed, without major complication. Response to the treatment was evaluated according to RECIST criteria every 6 weeks. Twenty-four hours after MWA, the dog was pain-free and had excellent mobility. Based on CT measurements, a reduction of the size of the lytic area was observed at the 2-month and at the 7-month follow-up (from 13% to 25% of the longest diameter), classified as stable disease according to RECIST criteria. The dog died 18 months after the initial diagnosis due to distant metastases.

Multifunctional 3D-printed scaffolds eradiate orthotopic osteosarcoma and promote osteogenesis via microwave thermo-chemotherapy combined with immunotherapy

Tumor recurrence and a lack of bone-tissue integration are two critical concerns in the surgical treatment of osteosarcoma. Thus, an advanced multifunctional therapeutic platform capable of simultaneously eliminating residual tumor cells and promoting bone regeneration is urgently needed for efficient osteosarcoma treatment. Herein, to thoroughly eliminate tumors and simultaneously promote bone regeneration, an intelligent multifunctional therapeutic scaffold has been engineered by integrating microwave-responsive zeolitic imidazolate framework 8 (ZIF-8) nanomaterials loaded with a chemotherapeutic drug and an immune checkpoint inhibitor onto 3D-printed titanium scaffolds. The constructed scaffold features distinct microwave-thermal sensitization and tumor microenvironment-responsive characteristics, which can induce tumor immunogenic death by microwave hyperthermia and chemotherapy. Orthotopic implantation of the nanocomposite scaffold results in an enhanced immune response against osteosarcoma that may effectively inhibit tumor recurrence through synergistic immunotherapy. During long-term implantation, the zinc ions released from the degradation of ZIF-8 can induce the osteogenic differentiation of stem cells. The porous structure and mechanical properties of the 3D-printed titanium scaffolds provide a structural microenvironment for bone regeneration. This study provides a paradigm for the design of multifunctional microwave-responsive composite scaffolds for use as a therapy for osteosarcoma, which could lead to improved strategies for the treatment of the disease.

Does joint-sparing tumor resection jeopardize oncologic and functional outcomes in non-metastatic high-grade osteosarcoma around the knee?

BACKGROUND

We previously reported joint-sparing tumor resection for osteosarcoma with epiphyseal involvement in which transepiphyseal osteotomy went through the in situ ablated epiphysis. However, we do not know whether this is a safe approach when compared with joint-sacrificed tumor resection. Our objective was to compare oncologic and functional outcomes between patients who underwent joint preservation (JP) and joint replacement (JR) tumor resection. Furthermore, we identified the risk factors of local recurrence, metastasis and survival.

METHODS

Eighty-nine patients with non-metastatic high-grade osteosarcoma around the knee were treated with limb-salvage surgery (JP in 47 and JR in 42). Age, gender, tumor location, pathologic fracture, plain radiographic pattern, limb diameter change, perivascular space alteration, surgical margin, local recurrence, metastasis, death, and the Musculoskeletal Tumor Society (MSTS)-93 scores were extracted from the records. Univariate analysis was performed to compare oncologic and functional outcomes. Binary logistic and cox regression models were used to identify predicted factors for local recurrence, metastasis, and survival.

RESULTS

Local recurrence, metastasis and overall survival were similar in the JP and JR group (p = 0.3; p = 0.211; p = 0.143). Major complications and limb survival were also similar in the JR and JP group (p = 0.14; p = 0.181). The MSTS score of 27.06 ± 1.77 in the JP group was higher than that of 25.88 ± 1.79 in the JR group (p = 0.005). The marginal margin of soft tissue compared with a wide margin was the only independent predictor of local recurrence (p = 0.006). Limb diameter increase and perivascular fat plane disappearance during neoadjuvant chemotherapy were independent predictors for metastasis (p = 0.002; p = 0.000) and worse survival (p = 0.000; p = 0.001).

CONCLUSIONS

Joint-sparing tumor resection with the ablative bone margin offers advantage of native joint preservation with favorable functional outcomes while not jeopardizing oncologic outcomes compared with joint-sacrificed tumor resection. Surgeon should strive to obtain adequate soft tissue surgical margin decreasing risk of local recurrence. Novel drug regimens might be reasonable options for patients with obvious limb diameter increase and perivascular fat disappearance during chemotherapy.

A classification system of joint-salvage tumor resection in osteosarcoma of the knee: A retrospective cohort study

BACKGROUND

Joint-preserving surgery is possible for patients with juxta-articular osteosarcoma of the knee, even when the tumor invades the epiphysis. Oncologic and functional outcomes may vary due to the extent of tumor invasion, the amount of epiphysis preservation, and reconstruction methods. We aimed to introduce a novel classification facilitating clinical evaluation of different surgical treatments.

METHODS

We identified 52 patients with osteosarcoma of the knee undergoing joint-preserving tumor resection and intercalary reconstruction. We classified procedures into two types and six subtypes based on the tumor location and adjuvant treatment employed. Oncologic outcomes, limb function and complications were compared among different types.

RESULTS

None of the patients had a local recurrence in the preserved epiphysis apart from three (5.7 %) who had local recurrence in soft tissue. Overall survival rate of the patients was 82.7 % at 5 and 10 years. There was no difference in survival rate (P = 0.909), local recurrence (P = 0.642) between type I (tumor not invading epiphysis) and type II (tumor invading epiphysis). In addition to one skin necrosis in the 3D-printed prosthesis reconstruction and one infection in Capanna reconstruction, all complications necessitating additional surgery occurred in allograft. The Musculoskeletal Tumor Society (MSTS) scores ranged from 21 to 30 with a median of 26. There were differences in the MSTS scores among six subgroups (P = 0.015), with the highest in type Ia and the lowest in type IIc. The less of the viable epiphysis retained, the worse the knee function was at long-term follow up.

CONCLUSIONS

The suggested classification can guide surgical strategy and is convenient for comparison of the functional results.

Percutaneous ablation of malignant and locally aggressive solid tumors in pediatric patients

Image-guided percutaneous ablation is an accepted treatment modality for common adult cancers. Unfortunately, its use in patients younger than 18 years is rare. This retrospective review presents our series of pediatric patients treated with ablation at our institution. From January 2002 to December 2021, a total of 14 patients (17 lesions) younger than 18 years were treated with percutaneous image-guided ablation. Estimated overall survival at 5 years was 58%; median survival of this group was not reached. Estimated local tumor progression-free survival at 5 years was 62%. One major complication was recorded.

Conservative surgery with microwave ablation for recurrent bone tumor in the extremities: a single-center study

BACKGROUND

Surgical treatment for recurrent bone tumors in the extremities still presents a challenge. This study was designed to evaluate the clinical value of microwave ablation in the treatment of recurrent bone tumors.

METHODS

We present 15 patients who underwent microwave ablation for recurrent bone tumors during the last 7 years. The following parameters were analyzed for outcome evaluation: general condition, surgical complications, local disease control, overall survival, and functional score measured using the Musculoskeletal Tumor Society (MSTS) 93 scoring system.

RESULTS

Percutaneous microwave ablation in one patient with osteoid osteoma and another with bone metastasis resulted in postoperative pain relief. Thirteen patients received intraoperative microwave ablation before curettage or resection, including those with giant cell tumors of bone (6), chondroblastoma (2), osteosarcoma (2), undifferentiated sarcoma (1), and bone metastases (2). All patients achieved reasonable local tumor control in the mean follow-up of 29.9 months. The functional score was 24.1 for the 15 patients 6 months after the operation. Four patients had tumor metastasis and died, whereas 3 patients with tumors survived, and the remaining 8 patients without the disease survived.

CONCLUSIONS

Microwave ablation represents an optional method for local control in treating recurrent bone tumors in the extremities.

Microwave in situ inactivation in the treatment of bone giant cell tumor: a mid-term descriptive study

AIM

To evaluate the mid-term clinical efficacy of microwave in situ inactivation combined with bone grafting or polymethyl methacrylate (PMMA) filling in the treatment of giant cell tumor of bone (GCTB).

METHODS

This is a retrospective, descriptive, and analytical study. A total of 30 GCTB patients received microwave in situ inactivation from January 2012 to January 2020, whose clinical recurrence rate was evaluated at the last follow-up after microwave in situ inactivation surgery. The Musculoskeletal Tumor Society (MSTS) function score was used to evaluate the postoperative clinical panoramic results.

RESULTS

All patients were followed up for 21 to 110 months, with an average of 63.79 months. Distal femur (40%) and proximal tibia (28%) had a higher rate of GCTB incidence. Seventeen percent of tumor patients suffered from associated pathologic fracture. The rate of Campanacci classification stage III was 60%. The average MSTS score was evaluated as 27.53 points overall at the last follow-up. In terms of complications, three, two, two and one cases developed fat liquefaction, controllable tissue rejection reaction, incision infection and degenerative changes around lesion joint, respectively, without in situ recurrences and reoperation as well as distant lung metastasis.

CONCLUSIONS

The method of microwave in situ inactivation combined with bone grafting or PMMA filling is prudently recommended as one of the options for the limb salvage treatment of giant cell tumor of long and periarticular bone.

LEVEL OF EVIDENCE

IV: case series.

Unfolded Protein Response-Related Signature Associates With the Immune Microenvironment and Prognostic Prediction in Osteosarcoma

Background: Osteosarcoma is a highly malignant bone tumor commonly occurring in adolescents with a poor 5-year survival rate. The unfolded protein response (UPR) can alleviate the accumulation of misfolded proteins to maintain homeostasis under endoplasmic reticulum stress. The UPR is linked to the occurrence, progression, and drug resistance of tumors. However, the function of UPR-related genes (UPRRGs) in disease progression and prognosis of osteosarcoma remains unclear.

Methods: The mRNA expression profiling and corresponding clinical features of osteosarcoma were acquired from TARGET and GEO databases. Consensus clustering was conducted to confirm different UPRRG subtypes. Subsequently, we evaluated the prognosis and immune status of the different subtypes. Functional analysis of GO, GSEA, and GSVA was used to reveal the molecular mechanism between the subtypes. Finally, four genes (STC2, PREB, TSPYL2, and ATP6V0D1) were screened to construct and validate a risk signature to predict the prognosis of patients with osteosarcoma.

Result: We identified two subtypes according to the UPRRG expression patterns. The subgroup with higher immune scores, lower tumor purity, and active immune status was linked to a better prognosis. Meanwhile, functional enrichment revealed that immune-related signaling pathways varied markedly in the two subtypes, suggesting that the UPR might influence the prognosis of osteosarcoma via influencing the immune microenvironment. Moreover, prognostic signature and nomogram models were developed based on UPRRGs, and the results showed that our model has an excellent performance in predicting the prognosis of osteosarcoma. qPCR analysis was also conducted to verify the expression levels of the four genes.

Conclusion: We revealed the crucial contribution of UPRRGs in the immune microenvironment and prognostic prediction of osteosarcoma patients and provided new insights for targeted therapy and prognostic assessment of the disease.

Cryoablation-aided joint retention surgery for epiphysis involvement in osteosarcoma compared with endoprosthetic replacement

AIMS

We have previously reported cryoablation-assisted joint-sparing surgery for osteosarcoma with epiphyseal involvement. However, it is not clear whether this is a comparable alternative to conventional joint arthroplasty in terms of oncological and functional outcomes.

METHODS

A total of 22 patients who had localized osteosarcoma with epiphyseal involvement around the knee and underwent limb salvage surgery were allocated to joint preservation (JP) group and joint arthroplasty (JA) group. Subjects were followed with radiographs, Musculoskeletal Tumor Society (MSTS) score, and clinical evaluations at one, three, and five years postoperatively.

RESULTS

Patients in both groups (ten in JP and 12 in JA) did not differ in local recurrence (p ≥ 0.999) and occurrence of metastases (p ≥ 0.999). Overall survival was similar in both groups (p = 0.858). Patients in the JP group had less range of motion (ROM) of the knee (p < 0.001) and lower MSTS scores (p = 0.010) compared with those of the JA group only at one year postoperatively. There was no difference between groups either at three years for ROM (p = 0.185) and MSTS score (p = 0.678) or at five years for ROM (p = 0.687) and MSTS score (p = 0.536), postoperatively. Patients in the JA group tended to have more complications (p = 0.074). Survival of primary reconstruction in the JP group was better than that of the JA group (p = 0.030).

CONCLUSION

Cryoablation-aided joint-sparing surgery offers native joint preservation with comparable functional recovery and more durable reconstruction without jeopardizing oncological outcomes compared with conventional limb salvage surgery. Cite this article: Bone Joint J 2021;103-B(8):1421-1427.

What's New in Pediatric Orthopaedic Tumor Surgery

BACKGROUND

Pediatric Orthopaedic Oncology is a developing subspecialty within the field of Pediatric Orthopaedics. Traditionally, the field of Orthopaedic Oncology has been focused on the skeletally mature individual, and the research tends to be all encompassing rather than truly evaluating isolated populations. The purpose of this review is to summarize the most clinically relevant literature in the field of Pediatric Orthopaedic Oncology over the last 6 years.

METHODS

We evaluated the PubMed database utilizing keywords for pediatric orthopaedic oncology: sarcoma, osteosarcoma, Ewing sarcoma, bone cyst. In additionally, we further broadened our search by searching for relevant articles in the contents sections of major orthopaedic surgery journals that routinely publish both pediatric and orthopaedic oncology literature. In keeping with "What's New," we selected the most clinically relevant articles published in the last 6 years from January 1, 2014 through February 2020. Basic science and systemic therapies literature was widely reviewed and the research and clinical trials most relevant to pediatric sarcoma and neoplastic processes found in the pediatric population were included.

RESULTS

Our search yielded 60 articles that met general criteria, from which 14 were determined to be most relevant to the goals of this paper. Of the papers presented in this review, there were papers related to management of benign tumors/tumor-like conditions, bone cysts, limb salvage procedures, and amputation procedures. Ultimately included in the review were 5 studies related to limb salvage, 4 related to bone cysts, 1 related to multiple hereditary exostoses, 2 related to osteofibrous dysplasia, 1 related to chondroblastoma, and 1 discussing cementation in skeletally immature patients. They were level III, IV, and V studies. Basic science and systemic therapies literature was widely reviewed and the research and clinical trials most relevant to pediatric sarcoma and neoplastic processes found in the pediatric population were included. Our search of the basic science and systemic therapies literature yielded 19 sources were found to be pertinent to our aims and 18 of those sources were published between 2015 and 2020.

CONCLUSIONS

There are many, varied, and creative procedures in the realm of limb salvage, though there remains a lack of high-level evidence to support some of the more novel procedures. In regards to benign bone tumors, despite a more solid base of literature, there still does not seem to be consensus as to the best treatment. In particular, there continue to be many schools of thought on the treatment of benign bone cysts. Research in the basic science arena and systemic therapies are advancing in exciting ways in regards to pediatric sarcoma. Orthopaedic oncologic research specific to the pediatric population overall continues to be impeded by low sample sizes and inadequate levels of evidence, which limits the ability of surgeons to draw definitive conclusions from the literature.

Novel Strategy of Curettage and Adjuvant Microwave Therapy for the Treatment of Giant Cell Tumor of Bone in Extremities: A Preliminary Study

Objectives

To evaluate whether curettage with adjuvant microwave therapy was successful in the treatment of giant cell tumor of the bone (GCTB) in extremities, especially for GCTB with pathological fractures and GCTB of the distal radius.

Methods

This was a retrospective study of 54 cases of GCTB of the extremities treated by curettage with adjuvant microwave therapy between 2007 and 2019. Five patients were lost to follow up and excluded from the study. A total of 33 male and 21 female patients were included in this study. Patients were aged 15–57 years (mean 29.72 ± 10.48 years). Among these patients, there were 10 cases of GCTB with pathological fractures and eight cases of GCTB of the distal radius; one of these cases was combined with a pathological fracture. Comprehensive imaging examinations (X‐rays [including lesion site and chest], CT, MRI, emission computed tomography, and pathology examination) of all patients were reviewed. The clinical staging of these patients were evaluated radiologically using the Campanacci classification system based on the extent of spread of the tumor. All patients underwent curettage with adjuvant microwave therapy. Clinical and imaging evaluations were performed in all cases to check for recurrence or metastasis. Lower limb and upper limber function were assessed using the Musculoskeletal Tumor Society score (MSTS), and wrist function was assessed according to the disabilities of the arm, shoulder and hand (DASH) score. Data on surgical‐related complications were recorded.

Results

All cases were followed up for 24–126 months (mean 60.69 ± 29.61 months). There were 24 patients with a Campanacci grade of 3 and 30 with a Campanacci grade of 2. The 52 patients were continuously disease‐free. The local recurrence rate was 3.70% (2 patients). One patient had recurrence in the proximal femur, and the other developed in soft tissue of the calf muscle. No recurrence occurred for GCTB of the distal radius. One recurrence occurred in a GCTB with pathological fractures. The intervals were 9 and 28 months, respectively. The cases of recurrence all had a Campanacci grade of 3 (8.33%). The median MSTS among the 54 patients was 27.67 ± 3.81. The mean wrist function DASH score was 8.30 ± 2.53. The mean MSTS was 28.67 ± 1.63 and 26.71 ± 5.49 for patients with GCTB of the distal radius and for those with pathological fractures, respectively. In comparing patients with and without pathological fractures, there was no significant difference in the MSTS functional score. Five patients had complications after the surgery.

Conclusion

Curettage with adjuvant microwave ablation therapy provided favorable local control and satisfactory functional outcomes in the treatment of GCTB, especially for cases with pathological fractures and those with GCTB of the distal radius.

Combined Massive Allograft and Intramedullary Vascularized Fibula as the Primary Reconstruction Method for Segmental Bone Loss in the Lower Extremity: A Systematic Review and Meta-Analysis

BACKGROUND

Reconstruction of segmental bone loss due to malignancy, infection, or trauma is a challenge for the reconstructive surgeon. The combination of a vascularized fibular flap with a cortical allograft provides a reliable reconstructive option in the lower extremity. In this systematic review, we describe the outcome of this technique for the treatment of segmental bone loss.

METHODS

A systematic review was performed on the use of a combined massive allograft and intramedullary vascularized fibula as a reconstruction method for large bone defects. We used PubMed, Embase, and the Wiley Cochrane Library.

RESULTS

Seventeen clinical articles were included between 1997 and 2017, reporting 329 cases of lower-extremity reconstructions. A meta-analysis was performed on primary union rates. The main outcome measures were primary union rate, complication rate, reintervention rate, and function after reconstruction. All publications showed relatively high complication (5.9% to 85.7%) and reintervention rates (10% to 91.7%) with good primary union rates (66.7% to 100%) and functional outcome (range of mean Musculoskeletal Tumor Society [MSTS] scores, 24 to 29 points).

CONCLUSIONS

The combination of a massive allograft with intramedullary vascularized fibula provides a single-step reconstruction method for large bone defects (>6 cm) in the lower extremity, with good long-term outcomes.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Clinical Guideline for Microwave Ablation of Bone Tumors in Extremities

Microwave ablation has been used to treat bone tumors in extremities for more than 30 years. With improved recognition, updated microwave equipment, and expanded clinical application, microwave ablation has recently been widely used to treat bone tumors. To standardize the application of microwave ablation in the clinical treatment of bone tumors in the limbs, research results and clinical experience involving the use of microwave ablation to treat bone tumors in the limbs have been summarized, and a clinical guideline has been designed. This guideline is aimed at providing a reliable clinical basis for indications, preoperative evaluation and decision-making, perioperative treatment, complications, and other issues via evidence-based medicine. Two aspects are considered-percutaneous microwave ablation and intraoperative microwave ablation of bone tumors in extremities. Ultimately, the guideline is intended to standardize treatment and improve the clinical efficacy of microwave ablation of bone tumors in extremities.

Evaluation of microwave ablation for local treatment of dogs with distal radial osteosarcoma: A pilot study

OBJECTIVE

To evaluate the feasibility and safety of microwave ablation (MWA) as a modality to induce tumor necrosis within distal radial osteosarcoma (OSA).

STUDY DESIGN

Pilot study.

ANIMALS

Six client-owned dogs with distal radius OSA confirmed by cytological examination.

METHODS

Dogs underwent computed tomography for surgical planning before general anesthesia for fluoroscopy-guided ablation. Computed tomography was repeated 48 hours after MWA, before amputation. The ablated tumor was evaluated with histopathology.

RESULTS

Six dogs underwent MWA of distal radius OSA. A lower power setting (30 W) was selected for the first two dogs to avoid collateral soft tissue damage. The power was increased to 75 W for the last four dogs. The temperature was maintained between 45°C and 55°C (113 °F-131 °F) at the bone/soft tissue interface. Tumor necrosis varied between 30% and 90% (median, 55%) according to histopathology. No intraoperative or periprocedural complications were observed.

CONCLUSION

Microwave ablation induced variable tumor necrosis and did not induce immediate postablation complications in these six dogs with distal radius OSA.

CLINICAL SIGNIFICANCE

These results justify further evaluation of MWA as a potential modality to treat primary bone lesions in dogs.

Guideline for Limb-Salvage Treatment of Osteosarcoma

Osteosarcoma is the most common primary malignant bone tumor, occurring mainly in children and adolescents, and the limbs are the main affected sites. At present, limb‐salvage treatment is considered as an effective basic standard treatment for osteosarcoma of the limb. China has a vast territory, but the development of technology is not balanced,which requires sufficient theoretical coverage, strong technical guidance and the application of limb‐salvage treatment guidelines to the treatment of osteosarcoma. Therefore, to standardize and promote the development of limb‐salvage surgery technology and improve the success rate of limb‐salvage treatment, this guide systematically introduces limb‐salvage techniques for the treatment of patients with limb osteosarcoma through definition of limb‐salvage treatment, surgical methods, efficacy evaluation, postoperative treatment and prevention of complications, rehabilitation guidance, and follow‐up advice.

Mild microwave ablation combined with HSP90 and TGF‑β1 inhibitors enhances the therapeutic effect on osteosarcoma

Osteosarcoma is the most common malignant bone tumour and the second leading cause of cancer-related death in children and adolescents. Microwave ablation has an excellent therapeutic effect on bone tumours by instantaneously increasing the temperature in the tumour; however, there is a risk of damaging the surrounding healthy tissues by exposure to a high temperature when the treatment power is too large. In the present study, two anti-tumour reagents, a heat shock protein 90 (HSP90) inhibitor (PF-04929113) and a transforming growth factor-β1 (TGF-β1) inhibitor (SB-525334) were employed to enhance the therapeutic effect of mild-power microwave ablation. It was revealed that microwaving to 48°C combined with HSP90 and TGF-β1 inhibitors significantly increased the apoptotic rate of VX2 cells. The same results were observed during in vivo experiments using New Zealand rabbits to model osteosarcoma. In addition, the results indicated that the expression of cytochrome c, caspase-3 and caspase-9 were upregulated in response to the treatment, which indicated that the mitochondrial apoptotic signalling pathway had been activated. These findings may provide a novel strategy for the development of microwave ablation in osteosarcoma treatment, which could effectively kill tumour cells without damaging the surrounding normal tissues.

Three-dimensional-printed intercalary prosthesis for the reconstruction of large bone defect after joint-preserving tumor resection

BACKGROUND

Joint-preserving intercalary tumor resection can result in better proprioception and a more normal joint function after reconstruction. However, most reported reconstruction techniques are usually associated with frequent complications. Therefore, the approach of reconstruction following joint-preserving tumor resection warrants further study.

METHODS

Between September 2016 and October 2018, 12 patients with metaphyseal malignant bone tumors around the knee joint were treated by joint-preserving intercalary resections with the aid of three-dimensional (3D)-printed osteotomy guide plates and reconstructions using 3D-printed intercalary prostheses. We assessed the accuracy of the resection by comparing the cross sections at the resection plane with 3D-printed matching surface of the prostheses. The functional outcomes, complications and oncological status were also evaluated.

RESULTS

All patients were observed for 7 to 32 months with an average follow-up of 22.5 months. The achieved resection was accurate, with accurate matching between the residual bone and prosthesis. The mean MSTS score was 28 (range, 26-30). Superficial infection occurred in two patients. Local recurrence was observed in one patient, while pulmonary metastasis was identified in one patient.

CONCLUSIONS

The personalized osteotomy guide plate and prosthesis based on 3D printing technique facilitate joint-preserving tumor resection and functional reconstruction. However, longer follow-up and larger sample size are required to clarify its long-term outcomes.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Efficacy of a Modified Scoring System to Facilitate Surgical Decision-making for Diaphyseal Malignancies: When is Devitalized Tumor-bearing Autograft of Value?

Objectives

To evaluate the validity of a modified scoring system (MSS) for inferring the bony quality of tumor‐bearing diaphyses and predicting the risk of reconstructive failure after devitalized bone replantation (DBR).

Methods

In this retrospective cohort study, we reviewed the records of 30 patients surgically treated for diaphyseal malignancies between 1996 and 2015. There were 18 male and 12 female subjects; the average age was 34.0 ± 24.5 years (8–82 years). Tumor locations comprised the femur (21), the humerus (4), the tibia (3), the radius (1), and the fibula (1). Histological diagnoses included osteosarcoma (13), metastases (4), Ewing sarcoma (3), chondrosarcoma (3), malignant fibrohistiocytoma (2), periosteal osteosarcoma (1), Langerhans cell sarcoma (1), lymphoma (1), rhabdomyosarcoma (1), and malignant giant cell tumor (1). All primary tumors were rated as stage IIB. Twenty patients underwent DBR. Prosthetic procedures and segmental autografting/allografting were performed in 7 and 3 cases, respectively. MSS (comprising 5 elements: pain, tumor location, bone destruction, localized dimension, and longitudinal dimension) for each patient was calculated in accordance with their preoperative presentations. Outcome measurements included oncological results, outcomes of reconstructions, complications, and functional preservation, presented using the musculoskeletal tumor society (MSTS) scale.

Results

Follow up was available in 29 cases for an average duration of 61.0 ± 49.9 months (12–152 months). Infection occurred in 2 patients (6.9%), primary nonunion in 6 (27.3%), metastases in 9 (31.9%), recurrences in 4 (13.8%), and deaths in 7 (24.1%); 1 subject underwent amputation due to recurrence following endoprosthetic replacement (3.4%). In the DBR group, fractures occurred in 4 cases (21.1%) and nonunion in 5 (25%); internal fixation was related to nonunion (nails, 44.4% vs plates, 9.1%, P = 0.02). MSS was associated with fractures of devitalized autografts (11.0 ± 1.2 vs 8.3 ± 1.8, P = 0.01); the system was efficacious in predicting chances of fractures of these grafts (P = 0.02). MSS ≥ 10 (with false positive rate ≤ 6.7%) suggested increased fracture probability (≥22.7%) after DBR; therefore, 10 was considered a cutoff value.

Conclusions

Diaphyseal malignancies with MSS ≥10 may contraindicate DBR for increased chances of reconstructive failure. In this situation, alternative procedures are advisable. Further investigations are warranted to assess the efficacy of MSS in implying the validity of DBR for diaphyseal malignancies.

[Progress of reconstruction in bone tumor surgery]

Bone tumor surgery involves tumor resection and subsequent reconstruction. With the development of surgical technique and new material, there is a great step toward bone and joint reconstruction in bone tumor surgery. Generally speaking, there are two major reconstructive methods including bio-reconstruction and mechanical reconstruction. In addition, three-dimensional printed prosthesis has been widely applied in the field of bone tumor surgery. The short-term result is encouraged; however, long-term results and related complications are seldom reported.

Advances in limb salvage treatment of osteosarcoma

Osteosarcoma is the most common primary malignant bone tumor; its standard treatment includes neoadjuvant chemotherapy combined with surgery. Neoadjuvant chemotherapy has significantly improved the 5-year survival and limb salvage rates in osteosarcoma since the 1870s. The survival rate of patients with limb salvage was not inferior to that of amputees, and therefore, limb salvage has become the main surgical option for patients with osteosarcoma. The 5-year survival rate for osteosarcoma has plateaued. However, new advances in limb salvage therapy in osteosarcoma, including adjuvant chemotherapy, ablation techniques, bone transport techniques, and computer navigation techniques, are now available. This report summarizes the recent advances in limb salvage therapy for osteosarcoma over the past decade.

Image-Guided Thermal Ablative Therapies in the Treatment of Sarcoma

OPINION STATEMENT

Percutaneous thermal ablation, including microwave ablation (MWA), radiofrequency ablation (RFA), and cryoablation, is a well-established focal treatment option for primary and metastatic malignancies. While published literature specific to ablation of sarcomas is relatively lacking compared with non-sarcomatous malignancies, what is available is promising. In situations where a focal treatment option is desired, strong consideration should be given to percutaneous thermal ablation, in addition to surgery and radiation therapy. A significant advantage of percutaneous thermal ablation over surgery and radiation includes the repeatability of ablation, as there is no absolute limit on the number of times an ablation can be performed. Compared with surgery, ablation offers the potential of decreased recovery time, a less invasive procedure, and is often performed in patients deemed not medically fit for surgery.

What are the Oncologic and Functional Outcomes After Joint Salvage Resections for Juxtaarticular Osteosarcoma About the Knee?

BACKGROUND

Joint salvage surgery for patients with juxtaarticular osteosarcoma remains challenging, especially when the tumor invades the epiphysis. Because patients are surviving longer with current chemotherapy regimens, it is advantageous to retain native joints if possible, especially in young patients. However, the results using joint-preserving tumor resections in this context have not been well characterized.

QUESTIONS/PURPOSES

(1) What are the functional outcomes after limb salvage surgery at a minimum of 3 years? (2) What are the oncologic outcomes? (3) Is joint salvage surgery for epiphyseal tumors associated with an increased risk of local recurrence compared with metaphyseal tumors not invading the epiphysis? (4) What are the complications associated with joint salvage surgery?

METHODS

Between 2004 and 2013, we treated 117 patients with juxtaarticular osteosarcoma; of those, 43 (38%) were treated with joint salvage surgery, and 41 (95%) of the 43 patients are included in our study. The other two (5%) were lost to followup before 3 years (mean, 4.4 years; range, 3-11 years,). During the period in question, we generally performed joint salvage surgery in these patients when they had a favorable response to chemotherapy, did not have a pathologic fracture or extrusion of the tumor into the joint, and did not have a whole-epiphyseal osteolytic lesion, a large mass, or obvious neurovascular involvement. This report is a followup of an earlier study; the current study includes an additional nine patients, and additional followup of a mean of 19 months for the patients included in the earlier report. We ascertained overall survival and survival free from local recurrence which was estimated using the Kaplan-Meier method, functional status of the limb which was evaluated using the Musculoskeletal Tumor Society (MSTS)-93 scoring system, and recorded reconstructive complications including infection, fracture, skin necrosis, and nonunion. We compared oncologic and functional outcomes between patients with (n = 28) and without tumor extension to epiphysis (n =13). We also compared oncologic and functional outcomes among patients with different adjuvant treatments including microwave ablation (n = 11), cryoablation (n = 12), and navigation-assisted osteotomy (n = 5). Complications were tallied using records from our institutional database.

RESULTS

The overall Kaplan-Mayer survival rate was 82% (95% CI, 104-128 months) at 5 years. The overall Kaplan-Meier survivorship from local recurrence was 91% at 5 years (95% CI, 115-133 months). Three patients had a local recurrence, but none had local recurrence in or close to the remaining epiphysis. The MSTS scores ranged from 22 to 30 points, with a median of 28. There were no differences in survival rate, local recurrence, or MSTS scores between patients with a tumor that did not invade the epiphysis and those in whom the tumor did invade the epiphysis. There were differences in MSTS scores among patients with epiphyseal tumor extension in which different adjuvant techniques, including microwave ablation, cryoablation, and navigation-assisted osteotomy, were used. Additional surgical procedures were recorded for 10 patients (24%). Osteonecrosis of the residual epiphysis was detected 13 patients (31%).

CONCLUSIONS

Our findings suggest it is possible to salvage joints in selected patients with juxtaarticular osteosarcoma around the knee. The patients who have a favorable response to chemotherapy are the best candidates for this approach. Future studies might explore the role of adjuvant techniques of microwave ablation and cryoablation, particularly when the tumor invades the epiphysis, and whether resections can be facilitated with navigation.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Is Limb Salvage With Microwave-induced Hyperthermia Better Than Amputation for Osteosarcoma of the Distal Tibia?

BACKGROUND

Amputation has been the standard surgical treatment for distal tibia osteosarcoma owing to its unique anatomic features. Preliminary research suggested that microwave-induced hyperthermia may have a role in treating osteosarcoma in some locations of the body (such as the pelvis), but to our knowledge, no comparative study has evaluated its efficacy in a difficult-to-treat location like the distal tibia.

QUESTIONS

Does microwave-induced hyperthermia result in (1) improved survival, (2) decreased local recurrence, (3) improved Musculoskeletal Tumor Society (MSTS) scores, or (4) fewer complications than amputation in patients with a distal tibial osteosarcoma?

METHODS

Between 2000 and 2015, we treated 79 patients for a distal tibia osteosarcoma without metastases. Of those, 52 were treated with microwave-induced hyperthermia, and 27 with amputation. Patients were considered eligible for microwave-induced hyperthermia if they had an at least 20-mm available distance from the tumor edge to the articular surface, good clinical and imaging response to neoadjuvant chemotherapy, and no pathologic fracture. Patients not meeting these indications were treated with amputation. In addition, if neither the posterior tibial artery nor the dorsalis pedis artery was salvageable, the patients were treated with amputation and were not included in any group in this study. A total of 13 other patients were treated with conventional limb-salvage resections and reconstructions (at the request of the patient, based on patient preference) and were not included in this study. All 79 patients in this retrospective study were available for followup at a minimum of 12 months (mean followup in the hyperthermia group, 79 months, range 12-158 months; mean followup in the amputation group, 95 months, range, 15-142 months). With the numbers available, the groups were no different in terms of sex, age, tumor grade, tumor stage, or tumor size. All statistical tests were two-sided, and a probability less than 0.05 was considered statistically significant. Survival to death was evaluated using Kaplan-Meier analysis. Complications were recorded from the patients' files and graded using the classification of surgical complications described by Dindo et al.

RESULTS

In the limb-salvage group, Kaplan Meier survival at 6 years was 80% (95% CI, 63%-90%), and this was not different with the numbers available from survivorship in the amputation group at 6 years (70%; 95% CI, 37%-90%; p = 0.301).With the numbers available, we found no difference in local recurrence (six versus 0; p = 0.066). However mean ± SD MSTS functional scores were higher in patients who had microwave-induced hyperthermia compared with those who had amputations (85% ± 6% versus 66% ± 5%; p = 0.008).With the numbers available, we found no difference in the proportion of patients experiencing complications between the two groups (six of 52 [12%] versus three of 27 [11%]; p = 0.954).

CONCLUSIONS

We were encouraged to find no early differences in survival, local recurrence, or serious complications between microwave-induced hyperthermia and amputation, and a functional advantage in favor of microwave-induced hyperthermia. However, these findings should be replicated in larger studies with longer mean duration of followup, and in studies that compare microwave-induced hyperthermia with conventional limb-sparing approaches.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Assessment of fracture risk in proximal tibia with tumorous bone defects by a finite element method

There has not been a satisfying method to predict the fracture risk in tumorous bone lesions. To tackle this challenge, we used a finite element method to assess the fracture risk in the proximal tibia (pT) when the size and location of the tumorous defects are varied in bone. Towards this end, the circular cortical defects, mimicking the tumorous lesions by forming cortical window defects, with a diameter (Ф) of 20, 30, 40, or 50 mm, are structured on the anteromedial, lateral, posterior wall of pT, which is located 5, 15, and 25 mm below articular margin, respectively. We found that under walking conditions, the Von Mises Stress of each defective tibia model was larger than that of the intact tibia model and also showed a positive linear correlation with the sizes of the defects. A notable fracture risk was not observed until the defect was Ф30 mm or larger. When the defect emerged, the anteromedial wall resisted fracture risk more than the rest of wall. Our results show that the size and location of the bone tumors are important factors affecting the fracture risk of pT. Our findings will be beneficial to clinicians when deciding what treatment to use for pT lesions.

Impacts of Tumor Location, Nature and Bone Destruction of Extremity Osteosarcoma on Selection of Limb Salvage Operative Procedure

OBJECTIVE

To study the impacts of tumor location, nature and extent of bone destruction on selection of operative protocol for extremity osteosarcoma (OS).

METHODS

The medical records of 201 patients with extremity OS treated in our institute from December 1999 to June 2014 were retrospectively reviewed. Ninety eligible patients (56 males and 34 females) of average age 20 ± 11 years (range, 4-40 years) were enrolled. Tumor locations were categorized as diaphyseal (4; diaphysis group) or juxta-articular (86); the latter being subclassified as with (51, type III, epiphysis group) or without invasion beyond the epiphyseal line or plate (35, type I and II, metaphysis group) according to MRI images. Tumor nature (osteogenic, 51; osteolytic, 39) was determined radiologically. Extent of bone destruction was quantitated according to Mirel's scoring system to obtain an "invasion score". Regular postoperative follow-up included physical examination and imaging evaluation.

RESULTS

Fifty-four patients underwent biological reconstruction and 36 mechanical reconstruction. The mean follow-up duration was 51 months (range, 6-176 months, including four deaths within 12 months). Biological reconstruction was performed more frequently in the diaphysis and metaphysis groups (31/39, 79.5%) than mechanical reconstruction (8/39, 20.5%, P < 0.05). Biological reconstruction and articular preservation were associated with more satisfactory limb function (MSTS scores: 25.0 ± 3.3 and 25.1 ± 3.6) than mechanical reconstruction and articular resection (MSTS scores: 23.4 ± 3.7 and 23.1 ± 3.4, P < 0.05). Reconstruction methods and articular preservation had no relationship with overall or tumor-free survival (P > 0.05). Osteolytic lesions were associated with more extensive bone destruction than osteogenic lesions according to invasion scores (P < 0.05). Following biological reconstruction, high invasion scores (>8) had a 13.5-fold risk of fracture compared with low scores (≤8) (P < 0.05). Twenty-one subjects had recurrences, 30 metastases and 26 died. Postoperative complications included infection (6), fracture (10), and prosthesis loosening (4). Kaplan-Meier analysis indicated 5- and 10-year survival rates of 68.9% and 62.8%, respectively, and 5- and 10-year tumor-free survival rates of 66.7% and 57.8%, respectively.

CONCLUSION

Selection of limb salvage operative protocol for extremity OS should rely on tumor location, nature and extent of bone destruction. Regardless of tumor site, mechanical reconstruction is indicated for tumors with high invasion scores (>8), whereas biological reconstruction is preferred for those with low invasion scores (≤8). Tumors sparing the epiphyseal line or plate are ideal candidates for articular preservation.

Status and advancement of microwave ablation in China

Tumour ablation is defined as the direct application of chemical or thermal therapy to eradicate or substantially destroy a tumour. Currently, minimally invasive ablation techniques are available for the local destruction of focal tumours in multiple organ sites. Microwave ablation (MWA) is premised on the biological response of solid tumours to tissue hyperthermia, and it is a relatively low-risk procedure. Due to several advantages of MWA, including higher thermal efficiency, higher capability for coagulating blood vessels, faster ablation time and the simultaneous application of multiple antennae, MWA could be a promising minimally invasive ablation technique for the treatment of solid tumours. Therefore, the use of MWA has developed rapidly in China during the last decade. Many successful studies have been performed, and widespread use has been achieved for multiple types of tumours in China, especially for liver cancer. This review will describe the state-of-the-art of MWA in China, including the development of MWA equipment and its application in the treatment of multiple types of tumours.