Myoepithelial Carcinoma of Soft Tissue: Report of Two Cases

CASE

A 40-year-old man was evaluated for a painful mass on his right calf, and a 36-year-old woman presented with a painless mass on her right foot. Final pathology revealed marked nuclear atypia and positivity for S100/SOX10 and AE1/AE3 confirming diagnoses of myoepithelial carcinoma. Both patients underwent surgical resection and are without evidence of local recurrence or metastatic disease at 1-year follow-up.

CONCLUSION

Soft-tissue tumors presenting in the extremities warrant careful evaluation and timely histopathologic diagnosis. Myoepithelial carcinomas are rare, aggressive tumors with a propensity for local recurrence and metastasis. Treatment of these tumors should be discussed by a multidisciplinary tumor team.

Internal hemipelvectomy: A single institution's learning curve and longitudinal experience

BACKGROUND AND OBJECTIVES

Wide margin resection for pelvic tumors via internal hemipelvectomy is among the most technically challenging procedures in orthopedic oncology. As such, surgeon experience and technique invariably affect patient outcomes. The aim of this clinical study was to assess how an individual surgeon's experiences and advancements in technology and techniques in the treatment of internal hemipelvectomy have impacted patient outcomes at our institution.

METHODS

This study retrospectively examined a single tertiary academic institution's consecutive longitudinal experience with internal hemipelvectomy for primary sarcoma or pelvic metastases over a 26-year period between the years 1994 and 2020. Outcomes were assessed using two separate techniques. The first stratified patients into cohorts based on the date of surgery with three distinct "eras" ("early," "middle," and "modern"), which reflect the implementation of new techniques, including three-dimensional (3D) computer navigation and cutting guide technology into our clinical practice. The second method of cohort selection grouped patients based on each surgeon's case experience with internal hemipelvectomy ("inexperienced," "developing," and "experienced"). Primary endpoints included margin status, complication profiles, and long-term oncologic outcomes. Whole group multivariate analysis was used to evaluate variables predicting blood loss, operative time, tumor-free survival, and mortality.

RESULTS

A total of 72 patients who underwent internal hemipelvectomy were identified. Of these patients, 24 had surgery between 1994 and 2007 (early), 28 between 2007 and 2015 (middle), and 20 between 2016 and 2020 (modern). Twenty-eight patients had surgery while the surgeon was still inexperienced, 24 while developing, and 20 when experienced. Evaluation by era demonstrated that a greater proportion of patients were indicated for surgery for oligometastatic disease in the modern era (0% vs. 14.3% vs. 35%, p = 0.022). Fewer modern cases utilized freehand resection (100% vs. 75% vs. 55%, p = 0.012), while instead opting for more frequent utilization of computer navigation (0% vs. 25% vs. 20%, p = 0.012), and customized 3D-printed cutting guides (0% vs. 0% vs. 25%, p =  0.002). Similarly, there was a decline in the rate of massive blood loss observed (72.2% vs. 30.8% vs. 35%, p = 0.016), and interdisciplinary collaboration with a general surgeon for pelvic dissection became more common (4.2% vs. 32.1% vs. 85%, p < 0.001). Local recurrence was less prevalent in patients treated in middle and modern eras (50% vs. 15.4% vs. 25%, p =  0.045). When stratifying by case experience, surgeries performed by experienced surgeons were less frequently complicated by massive blood loss (66.7% vs. 40% vs. 20%, p = 0.007) and more often involved a general surgeon for pelvic dissection (17.9% vs. 37.5% vs. 65%, p = 0.004). Whole group multivariate analysis demonstrated that the use of patient-specific instrumentation (PSI) predicted lower intraoperative blood loss (p = 0.040). However, surgeon experience had no significant effect on operative time (p = 0.125), tumor-free survival (p = 0.501), or overall patient survival (p = 0.735).

CONCLUSION

While our institution continues to utilize neoadjuvant and adjuvant therapies following current guideline-based care, we have noticed changing trends from early to modern periods. With the advent of new technologies, we have seen a decline in freehand resections for hemipelvectomy procedures, and a transition to utilizing more 3D navigation and customized 3D cutting guides. Furthermore, we have employed the use of an interdisciplinary team approach more regularly for these complicated cases. Although our results do not demonstrate a significant change in perioperative outcomes over the years, our institution's willingness to treat more complex cases likely obscures the benefits of surgeon experience and recent technological advances for patient outcomes.

Hip Arthroplasty Outcomes in Patients with Metastatic Bone Disease

Background/Objective

The hip is a common location for metastatic bone disease (MBD) and surgical intervention is often indicated to relieve pain and improve function. MBD of the hip is usually treated with hemiarthroplasty or with total hip arthroplasty if there are acetabular lesions. As treatment for metastatic disease evolves and patients may expect to live longer after diagnosis, further evaluation of the complications and functional outcomes associated with hip arthroplasty for MBD are necessary.

Methods

This was a retrospective review of patients who underwent hip arthroplasty for MBD at a single institution between 2007 and 2021. Outcomes included rates of reoperation, complications, and overall survival.

Results

Ninety-three cases in 91 patients were included. Total hip arthroplasty (THA) was performed in 52 cases (55.9%), hemiarthroplasty in 15 (16.1%), and complex arthroplasty, including proximal femur replacement or THA with complex acetabular reconstruction, was performed in 26 (28%). There were 11 reoperations in five patients and six dislocations. Median survival was 10.4 months and one-year overall survival was 53.3%. There was a significant increase in the proportion of patients who were able to ambulate independently (35.2% vs 17.6%; p=0.02) and a significant decrease in patients confined to a wheelchair (18.7% vs 3.3%; p=0.045) after surgery.

Conclusions

Hip arthroplasty for MBD leads to relatively low rates of complications and reoperations in this population known to have high postoperative morbidity and mortality. Hip arthroplasty provides the majority of MBD patients with a durable reconstruction that exceeds their lifespan and enables them to return to an acceptable level of function.

Development and external validation of a machine learning model for prediction of survival in extremity leiomyosarcoma

PURPOSE

Machine learning (ML) models have been used to predict cancer survival in several sarcoma subtypes. However, none have investigated extremity leiomyosarcoma (LMS). ML is a powerful tool that has the potential to better prognosticate extremity LMS.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was queried for cases of histologic extremity LMS (n = 634). Patient, tumor, and treatment characteristics were recorded, and ML models were developed to predict 1-, 3-, and 5-year survival. The best performing ML model was externally validated using an institutional cohort of extremity LMS patients (n = 46).

RESULTS

All ML models performed best at the 1-year time point and worst at the 5-year time point. On internal validation within the SEER cohort, the best models had c-statistics of 0.75-0.76 at the 5-year time point. The Random Forest (RF) model was the best performing model and used for external validation. This model also performed best at 1-year and worst at 5-year on external validation with c-statistics of 0.90 and 0.87, respectively. The RF model was well calibrated on external validation. This model has been made publicly available at https://rachar.shinyapps.io/lms_app/ CONCLUSIONS: ML models had excellent performance for survival prediction of extremity LMS. Future studies incorporating a larger institutional cohort may be needed to further validate the ML model for LMS prognostication.

Development and external validation of a machine learning model for prediction of survival in undifferentiated pleomorphic sarcoma

PURPOSE

Machine learning (ML) algorithms to predict cancer survival have recently been reported for a number of sarcoma subtypes, but none have investigated undifferentiated pleomorphic sarcoma (UPS). ML is a powerful tool that has the potential to better prognosticate UPS.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was queried for cases of histologically confirmed undifferentiated pleomorphic sarcoma (UPS) (n = 665). Patient, tumor, and treatment characteristics were recorded, and ML models were developed to predict 1-, 3-, and 5-year survival. The best performing ML model was externally validated using an institutional cohort of UPS patients (n = 151).

RESULTS

All ML models performed best at the 1-year time point and worst at the 5-year time point. On internal validation within the SEER cohort, the best models had c-statistics of 0.67-0.69 at the 5-year time point. The Multi-Layer Perceptron Neural Network (MLP) model was the best performing model and used for external validation. Similarly, the MLP model performed best at 1-year and worst at 5-year on external validation with c-statistics of 0.85 and 0.81, respectively. The MLP model was well calibrated on external validation. The MLP model has been made publicly available at https://rachar.shinyapps.io/ups_app/ .

CONCLUSION

Machine learning models perform well for survival prediction in UPS, though this sarcoma subtype may be more difficult to prognosticate than other subtypes. Future studies are needed to further validate the machine learning approach for UPS prognostication.

The effect of timing between preoperative embolization and surgery: A retrospective analysis of hypervascular bone metastases

BACKGROUND AND OBJECTIVES

The optimal timing between preoperative embolization of hypervascular metastatic bone lesions and surgery has yet to be established. Our analysis sought to evaluate embolization timing impacts blood loss, transfusion risk, and operative time in patients with hypervascular primary tumors.

METHODS

We identified patients with renal cell (RCC) or thyroid carcinoma undergoing surgery between 1992 and 2023. Patients were segregated into the following cohorts: (1) no embolization preoperatively, (2) surgery <24 h of embolization, and (3) surgery >24 h after embolization. Multivariate logistic regression analyses were performed to assess the effect of embolization timing while controlling for confounding variables.

RESULTS

No differences were seen in all evaluated outcomes between immediate and delayed embolization cohorts. No differences in estimated blood loss were seen between the immediate (OR: 0.685, 95% CI: 0.159-2.949; p = 0.611) and delayed (OR: 0.568, 95% CI: 0.093-3.462; p = 0.539) surgery cohorts compared with patients without embolization. Surgery >24 h after embolization was not associated with a higher risk of prolonged operative time (OR: 13.499, 95% CI: 0.832-219.146; p = 0.067).

CONCLUSIONS

These findings suggest that surgery may be safely delayed beyond 24 h from embolization without a higher risk of bleeding. In appropriately selected cohorts, embolization may not be needed preoperatively.

Rare Dedifferentiated Periosteal Chondrosarcoma with 11-Year Metastatic Relapse: A Case Report

A 50-year-old man presented for evaluation of a periscapular mass. Biopsy suggested a low-grade chondrosarcoma; however, the resected specimen revealed a grade 2 chondrosarcoma with a low-grade dedifferentiated mesenchymal component. The mass multiply recurred as chondrosarcoma without a dedifferentiated component before the patient developed lung metastases of chondrosarcoma without a dedifferentiated component 11 years after the initial diagnosis and died of disease. This is one of the first reported cases of a dedifferentiated chondrosarcoma with low-grade dedifferentiated component. While overall prognosis may be better than in typical dedifferentiated chondrosarcoma, this tumor demonstrated numerous local recurrences as well as metastasis.

Evaluation of Absolute Neutrophil Count in the Perioperative Setting of Sarcoma Resection

Introduction

Limb salvage surgery (LSS) is the preferred surgical treatment for bone sarcomas. Preoperatively, many patients receive chemotherapy and may develop neutropenia. No study has evaluated the effect of a low preoperative absolute neutrophil count (ANC) on postoperative outcomes following LSS.

Methods

This was a retrospective review of 114 patients who underwent LSS for bone sarcoma from 2010 to 2020. Preoperative lab values were analyzed by logistic regression to identify the risk of developing surgical complications within 30 days, surgical site infection (SSI), and reoperation.

Results

Three (2.6%) patients experienced a surgical complication within 30 days. Twelve (10.53%) patients experienced postoperative SSI. Twenty-nine (25.4%) required reoperation. Preoperative ANC was not a significant predictor of surgical complications within 30 days, SSI, or reoperation. The only independent predictor of worse overall survival was the presence of a pathologic fracture at the time of surgery.

Conclusion

This is the first study to evaluate preoperative ANC on postoperative outcomes following LSS. We report no significant differences in surgical complications within 30 days, SSI, or reoperation with low preoperative ANC. Future studies with larger cohorts of neutropenic patients are needed to evaluate these outcomes, as our cohort had very few neutropenic patients due to selection bias.

Clinical Outcomes Following Resection of Distal Lower Extremity Soft Tissue Sarcomas

OBJECTIVE

Resection of soft tissue sarcoma (STS) in the distal lower extremity can result in large soft tissue defects that create difficult wounds to manage and significant risks for complications. Often, the anticipated or resultant tissue defect or loss of functional anatomy is an indication for amputation over limb salvage. Soft tissue reconstruction managed by plastic and reconstructive surgery (PRS) may help offer limb salvage as a therapeutic option with acceptable oncologic outcomes and wound complication rates.

METHODS

This was a review of 52 patients who underwent resection of STS at the level of the knee or distal between 2010 and 2020. Plastic and reconstructive surgery soft tissue management was utilized in 40.4% (n = 21) of cases, most of whom would have otherwise been considered candidates for amputation.

RESULTS

The overall rate of limb salvage was 76.9%. The overall rate of wound complications was 19.2%. The overall rate of negative margins of resection was 92.3%. The 1-, 5-, and 10-year overall survival probabilities were 92%, 85%, and 85%, respectively. Of the 40 limb salvage procedures, two required subsequent amputation, one for multiply recurrent disease and one for necrosis. The wound complication rate was 14.3% in the PRS management group and 22.6% in cases of wound closure managed by the primary surgeon. There were zero instances of total wound or flap loss in PRS- managed closures. When comparing patients with wound complications to those without, there was no difference in age (59.5 ± 21 vs. 51 ± 18 years, p = 0.42), body mass index (31.1 ± 4.8 vs. 26.1 ± 7.1 kg/m2 , p = 0.19), or tumor size (6.8 ± 5.0 vs. 6.4 ± 4.7 cm, p = 0.82). At final follow-up, 67% (n = 35) of patients were alive and disease-free.

CONCLUSIONS

Wound complications are not uncommon after resection of distal lower extremity STS. Our experience has been successful in achieving limb salvage in these challenging cases. Without PRS soft tissue management, however, many patients may alternatively be candidates for amputation.

Total Knee Arthroplasty for Osteoarthritis Is Uncommon after Intralesional Curettage in Giant Cell Tumor of Bone

Giant cell tumor of bone (GCTB) is most often treated with intralesional curettage; however, periarticular lesions have been shown to increase risk for osteoarthritis. Additionally, the location of these lesions may occasionally preclude a joint-sparing procedure in recurrent tumors. This study sought to investigate rates of secondary arthroplasty in long-term follow-up of knee GCTB. Cases of knee GCTB treated at our institution were reviewed. Rates of recurrence and secondary arthroplasty were recorded, and Kaplan-Meier survival analyses were performed. The records of 40 patients were reviewed. Local recurrence occurred in 25% of patients. The 1-, 5-, and 10-year recurrence-free survival (RFS) probability was 87.4% (95% CI, 77.0-97.7), 72.4% (95% CI, 57.6-87.2), and 72.4% (95% CI, 57.6-87.2), respectively. Function improved after surgery with a mean preoperative MSTS score of 14.9 (standard deviation [SD] 8.4) and mean postoperative MSTS score of 25.1 (SD 5.6) (p <0.001). Three patients had evidence of radiographic osteoarthritis at the last follow-up though they did not require arthroplasty. Arthroplasty was performed as a secondary procedure in six patients. Five patients underwent arthroplasty for recurrent tumors after initial treatment with curettage and one patient underwent patellar arthroplasty for osteoarthritis after initial treatment with an allograft composite arthroplasty. Arthroplasty is performed as a secondary procedure in patients with GCTB at a relatively infrequent rate and more often for cases of recurrent disease than for osteoarthritis. Overall, patients treated for GCTB have improved functional outcomes after surgery than before. Large, multi-institutional studies may be required to assess the incidence of secondary osteoarthritis requiring arthroplasty as this was an infrequent finding in our cohort.

Opiate use after total hip arthroplasty for metastatic bone disease

OBJECTIVES

To investigate post-operative opioid use following a total hip arthroplasty (THA) in metastatic bone disease (MBD) patients and identify factors associated with post-operative opioid use at 6 weeks and 90 days.

BACKGROUND

MBD commonly affects the hip, and surgical intervention including THA may be indicated for pain relief or to improve function. Following THA, patients are often prescribed short courses of opioids for post-operative pain relief. No study has evaluated opiate use following THA in patients for MBD.

METHODS

This was a retrospective review of patients using opioids preoperatively who underwent primary THA for MBD at two institutions between 2009 and 2022. Preoperative and post-operative opioid usages, respectively, at 6 weeks and 90 days were quantified through calculating daily morphine milligram equivalents (MMEs) and compared using the sign test. Factors associated with post-operative opioid use at 6 weeks and 90 days were compared using χ2 test or Fisher's exact test as appropriate.

RESULTS

Nineteen THA and 11 THA with complex acetabular reconstruction were included. At 6 weeks, 26 (86.7 percent) patients were utilizing opiates, and at 90 days, 23 (76.7 percent) patients were utilizing opiates. There was a statistically significant difference between median daily preoperative MME compared to daily MME at 90 days (p < 0.001). The only statistically significant association with opioid use at 90 days was opioid use at 6 weeks.

CONCLUSION

To our knowledge, this is the first paper evaluating post-operative opioid use following primary THA in MBD patients. After THA in the setting of MBD, patients exhibit decreased post-operative opioid use. Future studies with larger cohorts should be conducted to characterize post-operative opioid use following joint arthroplasty in MBD patients.

The First Cold Atmospheric Plasma Phase I Clinical Trial for the Treatment of Advanced Solid Tumors: A Novel Treatment Arm for Cancer

Local regional recurrence (LRR) remains the primary cause of treatment failure in solid tumors despite advancements in cancer therapies. Canady Helios Cold Plasma (CHCP) is a novel Cold Atmospheric Plasma device that generates an Electromagnetic Field and Reactive Oxygen and Nitrogen Species to induce cancer cell death. In the first FDA-approved Phase I trial (March 2020-April 2021), 20 patients with stage IV or recurrent solid tumors underwent surgical resection combined with intra-operative CHCP treatment. Safety was the primary endpoint; secondary endpoints were non-LRR, survival, cancer cell death, and the preservation of surrounding healthy tissue. CHCP did not impact intraoperative physiological data (p > 0.05) or cause any related adverse events. Overall response rates at 26 months for R0 and R0 with microscopic positive margin (R0-MPM) patients were 69% (95% CI, 19-40%) and 100% (95% CI, 100-100.0%), respectively. Survival rates for R0 (n = 7), R0-MPM (n = 5), R1 (n = 6), and R2 (n = 2) patients at 28 months were 86%, 40%, 67%, and 0%, respectively. The cumulative overall survival rate was 24% at 31 months (n = 20, 95% CI, 5.3-100.0). CHCP treatment combined with surgery is safe, selective towards cancer, and demonstrates exceptional LRR control in R0 and R0-MPM patients. (Clinical Trials identifier: NCT04267575).

Evaluation of Local Recurrence and Diagnostic Discordance in Chondrosarcoma Patients Undergoing Preoperative Biopsy

BACKGROUND/AIM

Preoperative biopsy of chondroid lesions has demonstrated discordance between biopsy grade and surgical resection grade. Furthermore, there is evidence to suggest risk of tumor contamination during biopsy. We evaluated our large chondrosarcoma institutional cohort to compare the rates of local recurrence based on pre-surgical biopsy, as well as other tumor characteristics and disease-related outcomes.

PATIENTS AND METHODS

This was a retrospective review of patients who underwent surgical resection for chondrosarcoma at our Institution between 2005 and 2020. Outcomes included rates of local recurrence, metastasis, and overall survival.

RESULTS

No significant differences were found in local recurrence and recurrence-free survival in cases of pre-operative biopsy. Thirteen (28.2%) patients had discordance between histological grade on biopsy and resection. Seven (63.6%) patients with dedifferentiation present on final resection were not identified on biopsy. The only independent predictor of recurrence-free survival and metastasis-free survival was the presence of dedifferentiation on resection.

CONCLUSION

To our knowledge, this is the first study evaluating risk of local recurrence in the setting of pre-surgical biopsy in chondrosarcoma patients. Although pre-operative biopsy may contaminate biopsy tracts, appropriate surgical planning and final resection results in no difference in local recurrence rates in this cohort. However, discordance rates between preoperative biopsy and resected specimen must be considered while determining clinical treatment.

Association between neutrophil-lymphocyte ratio, platelet-lymphocyte ratio, and survival in undifferentiated pleomorphic sarcoma (NLR, PLR, and overall survival in UPS)

BACKGROUND AND OBJECTIVES

Cancer-related inflammation has been shown to be a driver of tumor growth and progression, and there has been a recent focus on identifying markers of the inflammatory tumor microenvironment. Neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) are inflammatory indices that have been identified as prognostic biomarkers in various malignancies. However, there is limited and conflicting data regarding their prognostic value in soft tissue sarcoma (STS) and specifically in undifferentiated pleomorphic sarcoma (UPS).

METHODS

This was a retrospective review of patients who underwent surgical treatment for primary UPS from 1993 to 2021. Cutoff values for NLR and PLR were determined by receiver operating curve analysis. Cox proportional hazards regression was used to determine prognostic factors on univariate and multivariate analysis.

RESULTS

Eighty-six patients were included. The optimal cutoff value was 3.3 for NLR and 190 for PLR. Both high NLR (HR 2.44; 95% CI 1.29-4.63; p = 0.005) and high PLR (HR 1.99; 95% CI 1.08-3.67, p = 0.02) were associated with worse OS on univariate analysis. On multivariate analysis, metastasis at presentation and radiotherapy were independently predictive of OS, but high NLR (HR 1.30; 95% CI 0.64-2.98; p = 0.41) and high PLR (HR 1.63; 95% CI 0.82-3.25; p = 0.17) were not predictive of survival.

CONCLUSIONS

High pre-treatment NLR and PLR were associated with decreased overall survival but were not independent predictors of survival in patients undergoing resection for UPS. Until additional prospective studies can be done, survival outcomes are best predicted using previously established patient- and tumor-specific factors.

Epithelioid hemangioendothelioma of the distal lower extremity and the role of radiotherapy: A report of two cases

We report two cases of epithelioid hemangioendothelioma (EHE) in the distal lower extremity. Our first patient had unicentric EHE of the left os calcis initially treated with an intralesional procedure; however, later developed two recurrences which were managed with radiation therapy. Our second patient had multicentric EHE of the distal tibia and fibula managed with primary radiation therapy. Although EHE is typically treated with wide resection or an intralesional procedure, we present two cases of EHE in the distal lower extremity to discuss the therapeutic role of radiation therapy in the management of distal EHE.

Single-Stage Revision of Infected Total Femoral Replacement

We present 2 cases of infected total femur prosthetic devices treated with a single-stage revision with extensive irrigation and debridement, followed by reimplantation with a prosthesis coated in antibiotic-impregnated cement. Single-stage total femoral replacement with antibiotic-eluting cement around the device was used for 2 cases of limb salvage arthroplasty to reduce complications, maintain patient function, and minimize hospital-associated cost. [Orthopedics. 2022;45(5):e280-e283.].

Radiotherapy, volume reduction, and short-term surgical outcomes in the treatment of large myxoid liposarcomas

Purpose

While tumor volume reduction following radiation has been documented in myxoid liposarcomas, it is unclear whether large tumors experience similar volume reduction to smaller tumors.

Materials and Methods

MRI studies performed before and after completion of pre-operative radiation therapy (RT) were examined. Tumor sizes were noted and categorized as large versus small based on size >10 cm. Tumor volumes were calculated, and operative duration and major wound complications were recorded.

Results

The median largest tumor dimension was 12.4 cm before RT and 8.7 cm after RT. The median tumor volume was 298.9 cm3 before RT and 106.9 cm3 after RT. There was no significant difference in the mean percent tumor volume reduction between large tumors and small tumors (p = 0.11, 56.3% vs. 64.5%). Operative duration most strongly correlated to post-RT MRI volume (R2=0.674, p<0.001). Despite volume reduction, tumors that were large on presentation were more likely to experience major wound complications post-operatively.

Conclusion

Radiation appears to be as effective at reducing myxoid liposarcoma tumor volume in large and small tumors. However, large tumors on presentation appear more likely to experience wound complications despite tumor volume reduction. Future studies should investigate disease-related outcomes as a factor of volume reduction in myxoid liposarcoma.

External validation of machine learning models for prediction of survival in undifferentiated pleomorphic sarcoma

e13551

Background: Machine learning (ML) algorithms to predict cancer survival have recently been reported for a number of sarcoma subtypes, but none have investigated undifferentiated pleomorphic sarcoma (UPS). ML is a powerful tool that has the potential to better prognosticate UPS. Methods: The Surveillance, Epidemiology, and End Results (SEER) database was queried from 2004 to 2015 for cases of histologically confirmed undifferentiated pleomorphic sarcoma (UPS) and malignant fibrous histiocytoma (MFH). Patient, tumor, and treatment characteristics were recorded, and various machine learning (ML) models were built to predict 1-, 3-, and 5-year survival. The best performing ML models were externally validated using an institutional cohort of UPS patients. Results: All ML models performed best at the 1-year time point and worst at the 5-year time point. On internal validation within the SEER cohort, the best models had c-statistics of 0.71 to 0.73 at the 5-year time point. Similarly, all ML models performed best at 1-year and worst at 5-year on external validation. The best performing models had c-statistics of 0.81 at the 5-year time point on external validation, demonstrating good performance in survival prediction. Conclusions: Machine learning models perform well for survival prediction in UPS, though this sarcoma subtype may be more difficult to prognosticate than other subtypes. Future studies are needed to further validate the machine learning approach for UPS prognostication. [Table: see text]

Radiotherapy, volume reduction, and short-term surgical outcomes in the treatment of large myxoid liposarcomas

e23546

Background: While tumor volume reduction following radiation has been documented in myxoid liposarcomas, it is unclear whether large tumors experience similar volume reduction to smaller tumors. Methods: MRI studies performed before and after completion of pre-operative radiation therapy (RT) were examined. Tumor sizes were noted and categorized as large vs. small based on size > 10 cm. Tumor volumes were calculated, and operative duration and major wound complications were recorded. Results: The median largest tumor dimension was 12.4 cm before RT and 8.7 cm after RT. The median tumor volume was 298.9 cm3 before RT and 106.9 cm3 after RT. There was no significant difference in the mean percent tumor volume reduction between large tumors and small tumors (p = 0.11, 56.3% vs. 64.5%). Operative duration most strongly correlated to post-RT MRI volume (R2= 0.674, p < 0.001). Despite volume reduction, tumors that were large on presentation were more likely to experience major wound complications post-operatively. Conclusions: Radiation appears to be as effective at reducing myxoid liposarcoma tumor volume in large and small tumors. However, large tumors on presentation appear more likely to experience wound complications despite tumor volume reduction. Future studies should investigate disease-related outcomes as a factor of volume reduction in myxoid liposarcoma.[Table: see text]

Dedifferentiated Chondrosarcoma: A Case Series and Review of the Literature

BACKGROUND

Dedifferentiated chondrosarcoma (DCS) is a rare and aggressive malignancy with a poor prognosis. The purpose of this investigation was to describe our treatment and outcomes of 16 DCS patients at our institution and provide a review of the current literature.

METHODS

This study was a retrospective review over a consecutive twenty-year period. Data including treatment details and outcomes were recorded.

RESULTS

A total of 16 cases from 2000 to 2018 were identified. The median age (IQR) was 62 years (52; 69) and the majority of DCS arose in the femur (50%, n=8) and pelvis (25%, n=4). Fourteen (88%) cases underwent limb salvage/wide margin resection (n=13) or intralesional surgery (n=1). For all DCS, the median survival (IQR) was 46 months (12; 140), with both a five and ten-year probability of 32.1% (95% CI, 7.3% to 57.0%). At study conclusion, 81.3% (n=13) were deceased and 18.7% (n=3) were alive.

CONCLUSIONS

Our findings confirm the poor prognosis of DCS patients, with a five-year estimate of 32%. Together with existing literature, our data might help enable future strategic recommendation of these patients.

Indication for Proximal Femoral Replacement Is Associated With Risk of Failure

BACKGROUND

Proximal femoral replacement (PFR) is reserved as a salvage procedure after failed total hip arthroplasty (THA) or after wide margin resection of tumors involving the proximal femur. Although failure of the PFR construct remains a significant problem, indication has not previously been investigated as a risk factor for failure.

METHODS

This study retrospectively evaluated patients who underwent PFR over a consecutive 15-year period for primary sarcoma or metastatic disease of the proximal femur, compared with conversion to PFR after failed THA. PFR failure was defined as recurrent prosthetic dislocations, periprosthetic fracture, aseptic loosening, or infection that ultimately resulted in revision surgery.

RESULTS

Overall, 99 patients were evaluated, including 58 in the neoplasm and 41 in the failed THA cohorts. Failed THA patients were older (P < .001), with a greater proportion having comorbid hypertension (P = .008), cardiac disease (P = .014), and history of prior ipsilateral and intracapsular surgeries (P < .001). The failure rate was significantly higher in failed THA patients (39.0% vs 10.3%; P < .001) with significantly shorter implant survivorship on Kaplan-Meier analysis (P = .003). A multivariate Cox proportional hazards model showed that THA failure was the only independent predictor for PFR failure (hazard ratio: 4.26, 95% confidence interval: 1.66-10.94; P = .003).

CONCLUSION

This study revealed significantly worse PFR implant survivorship in patients undergoing PFR for the indication of failed THA compared with neoplasm. Although the underlying etiology of this relationship remains to be explicitly outlined, poor bone quality and soft tissue integrity, multiple prior surgeries, and comorbid conditions are likely contributing factors.

Extraskeletal myxoid chondrosarcoma: A case series and review of the literature

Background

Extraskeletal myxoid chondrosarcoma (EMC) is a rare malignant soft tissue sarcoma (STS) that accounts for less than 3% of all soft tissue tumors. The conventional treatment for primary EMC is wide local excision with or without radiation therapy.

Materials and Methods

This study was a retrospective review of all EMC cases treated within a single institution between 1992 and 2019. EMC was diagnosed using a combination of histologic morphology and immunostaining, with confirmatory fluorescent in situ hybridization. Overall survival (OS) and disease-specific survival (DSS) were defined using Kaplan–Meier analysis.

Results

Fifteen patients were evaluated, including 11 males and four females. The average age at presentation was 51.7 ± 20.4 years and the mean follow-up time was 61.5 months (range, 5–286 months). The average resected tumor size at largest dimension was 7.14 cm (range, 2.4–18.7). Twelve of fifteen (80%) patients underwent wide local excision, and nine of the twelve (75%) underwent local radiation therapy. The 1-, 5-, and 10-year OS was 80% (95% CI, 59.8–100), 72% (95% CI, 48.5–95.5), and 72% (95% CI, 48.5–95.5), respectively. The 1-, 5-, and 10-year DSS was 92.3% (95% CI, 77.8–100), 83.1% (95% CI, 61.5–100), and 83.1% (95% CI, 61.5–100), respectively. At last follow-up, 11 patients were alive and ten (90.9%) were disease free.

Conclusions

Extraskeletal myxoid chondrosarcoma is a very rare STS most often seen in males and in the extremities. Our cohort was too small to provide meaningful statistical analysis; however, we observed lower rates of local recurrence in patients treated with radiation.

3D-Printed Cutting Guides for Resection of Long Bone Sarcoma and Intercalary Allograft Reconstruction

The use of 3-dimensional (3D)-printed cutting guides for resection of long bone sarcoma is a novel technique. These 3D-printed guides provide a potential benefit over navigational or freehand osteotomy. We evaluated whether the use of 3D-printed cutting guides in the resection of long bone sarcoma affects margin status and rates of union compared with historical controls. In this study, we performed a retrospective review of a prospectively maintained surgical database and reviewed 6 patients who underwent limb salvage for long bone sarcoma. We collected and analyzed clinicopathologic and surgical data. Six (100%) cases recorded negative margins, with mean postoperative follow-up of 108 weeks (range, 8-211 weeks). Time (mean±SD) to bony union was 20.5±10.5 weeks. Nine of 12 (75%) cumulative (proximal and distal) osteotomy sites went on to achieve union, with a nonunion rate of 25% per osteotomy. One (33%) nonunion occurred after adjuvant radiation therapy. Long-term complications were limited to 2 (33.3%) patients overall who had implant failure according to the Henderson classification system, and there were zero local recurrences at the conclusion of the study. Our institution has successfully performed limb salvage surgery with patient-specific 3D-printed technology. We show high rates of negative margin resection and junctional union that align with and improve on earlier findings. [Orthopedics. 2022;45(1):e35-e41.].

What is the clinical impact of staging and surveillance PET-CT scan findings in patients with bone and soft tissue sarcoma?

BACKGROUND AND OBJECTIVES

Positron emission tomography-computerized tomography (PET-CTs) are becoming increasingly utilized in sarcoma care, workup, and surveillance. This study aimed to describe additional PET-CT findings as well as subsequent workups and changes in the clinical course due to those results.

METHODS

Patient records were retrospectively reviewed, and the additional workups and evaluations triggered by PET-CT findings were qualitatively analyzed to document their results. Additional changes in the clinical course were documented.

RESULTS

A total of 183 bone and soft tissue sarcoma patients underwent PET-CT as part of staging or surveillance. Additional workup was performed in 31.5% (n = 41 of 130) patients who had positive PET-CT findings. Among these, 36.6% (n = 15 of 41) patients had clinically significant findings that altered the clinical course. Overall, 14.8% (n = 27 of 183) experienced a change in the clinical course due to PET-CT.

CONCLUSION

PET-CT often highlights lesions of potential clinical importance. Additional workup, as well as changes in the clinical course, were not infrequent. Future, multi-institutional studies should address the value of PET-CT in sarcoma care.

The clinical utility of next-generation sequencing for bone and soft tissue sarcoma

Background: Sarcomas are a rare and heterogeneous tumor group composed of a variety of histologic subtypes. Targeted next-generation sequencing (NGS) of bone and soft tissue sarcomas is a nascent field with limited evidence for its use within clinical practice. Therefore, further research is needed to validate NGS in sarcoma and assess the clinical utility of these techniques with the hope of improving treatment options.Methods: Comprehensive molecular profiling with NGS was performed on 136 tumors (116 soft tissue, 20 bone) using two commercial vendors. Patient records were retrospectively reviewed, and the clinical impact of NGS-related findings were qualitatively analyzed to determine actionable mutations and number of changes in treatment.Results: The median age was 55.0 years (IQR 42-67 years), and most patients were non-metastatic at presentation (80.9%, n = 110). Prior to performing NGS, 72.1% (n = 98) were treated with a mean 1.1 ± 1.2 lines of systemic chemotherapy. NGS identified 341 putative alterations with at least one mutation present in 89.7% (n = 122) of samples. In a subset of 111 patients with available TMB data, 78.7% (n = 107) had a low (<6 m/Mb) mutational burden. Among all 136 cases, 47.1% (n = 64) contained clinically actionable alterations, and 12 patients had a change in medical treatment based on NGS. Those who underwent a treatment change all had metastatic or recurrent disease; three of these patients experienced a clinical benefit.Conclusion: Most bone and soft tissue sarcomas harbor at least one genetic alteration, and it appears a sizeable number of tumors contain mutations that are clinically actionable. While a change in treatment based off NGS-related findings occurred in 12 cases, three patients experienced a clinical benefit. Our data provide further proof-of-concept for NGS in sarcoma and suggest a clinical benefit may be observed in select patients.

Internal fixation versus endoprosthetic replacement of the proximal femur for metastatic bone disease: Single institutional outcomes

PURPOSE

This study compared internal fixation (IF) to proximal femur replacement (PFR) for proximal femoral metastasis.

METHODS

Between 2005 and 2019, 113 lesions underwent IF (n = 94) or PFR (n = 19). Revision risk was calculated with mortality as a competing event.

RESULTS

The 5-year revision risk after IF was 17.6% (95% CI, 9.8%-27.3%) compared to 7.6% (95% CI, 0.3%-28.9%) after PFR (p = 0.59). PFR had longer operative times (p < 0.001), hospital stay (p = 0.039), and higher blood loss (p < 0.001) than IF, respectively.

CONCLUSIONS

IF may be considered for patients with poor health and a limited prognosis given the less-invasive procedure and shorter hospital stay.

LEVEL OF EVIDENCE

III. Retrospective Study.

Dedifferentiated chondrosarcoma: A report of the clinicopathologic features and outcomes of 16 cases treated at a single institution

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Background: Dedifferentiated chondrosarcoma (DCS) is a rare and aggressive malignancy with a poor prognosis. The purpose of this investigation was to assess the clinicopathological features and outcomes of DCS patients treated at a single institution. Methods: This study was a retrospective review over a consecutive twenty-year period. Data including treatment details and outcomes were recorded. Results: A total of 16 cases from 2000 to 2018 were reviewed. The median age was 62 years (IQR, 52-69 years) and the majority of DCS arose in the femur (50%, n = 8) and pelvis (25%, n = 4). Fourteen (88%) cases received limb salvage/wide margin resection (n = 13) or intralesional surgery (n = 1). For all DCS, the median estimated overall survival (OS) was 46 months (95% CI, 1-90 months) with both a five and ten-year survival probability of 32%. On Kaplan-Meier analysis there was no difference between operative versus nonoperative management (p = 0.747), surgery alone versus surgery/chemotherapy (p = 0.265), nor surgery alone versus surgery/chemotherapy/radiation (p = 0.698). Conclusions: Our findings confirm the poor prognosis of DCS patients, though with a five-year estimate of 32%, higher than previous literature. Together with existing literature, our data may enable future strategic recommendation of DCS patients.

The prognostic significance of lymphovascular tumor invasion in localized high-grade osteosarcoma: Outcomes of a single institution over ten years

e22013

Background: Lymphovascular tumor invasion (LVI) has shown evidence of an association with worse survival in high-grade osteosarcoma. The purpose of this investigation was to prognosticate LVI as a predictor of survival in these patients. Methods: This study was a retrospective review of high-grade, localized osteosarcoma patients diagnosed over a consecutive ten-year period. Cox proportional hazards regression was used to assess the prognostic significance of LVI on overall survival (OS). Results: A total of 42 cases met inclusion criteria with a median follow-up of 64 months (range, 6-158 months). LVI was present in 21.4% (n = 9) cases. The five and ten-year probabilities of OS in LVI (+) were 40% and 20%, respectively, compared to LVI (-) with five and ten-year estimates of 93% and 81%, respectively (p < 0.001). After controlling for confounding variables, advanced age at diagnosis (HR, 1.134; 95% CI, 1-1.2; p = 0.01) and LVI (HR, 21.768; 95% CI, 3-135; p = 0.001) were found to be significantly negative predictors of OS. Using a competing risk analysis and Gray's test of equality, LVI (+) and LVI (-) were not statistically different with respect to cumulative incidence of recurrence (p = 0.8118), though were highly significant for cumulative incidence of mortality over time (p = 0.0029). Conclusions: The presence of LVI in the setting of high-grade, localized osteosarcoma is associated with greater rates of mortality and tumor recurrence and portends a dismal prognosis.

Comparison of clinicopathological features and outcomes in patients with primary leiomyosarcoma of bone and soft tissue

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Background: Leiomyosarcoma is a rare malignancy that may occur in bone. This investigation described the characteristics and outcomes of primary leiomyosarcoma of bone (PLB) compared to soft tissue leiomyosarcoma (SLMS). Methods: This study was a retrospective review using the Surveillance, Epidemiology, and End Results (SEER) database from 1975 to 2016. Continuous and categorial variables were described, and Cox regression were used to identify factors of prognostic significance. Results: Seven thousand five-hundred two patients met inclusion criteria. Seventy-four (1%) were PLB and 7428 (99%) were SLMS. On multivariable analysis for high-grade SLMS radiation (neoadjuvant: HR, 0.56; 95% CI, 0.4-0.8; p = 0.003, and adjuvant: HR, 0.75; 95% CI, 0.6-0.9; p = 0.008) and surgery (procedure specific) improved DSS, while age (HR, 1.013; 95% CI, 1.0-1.1; p < 0.001), tumor size greater than or equal to 5 cm (HR, 3.16; 95% CI, 2.3-4.2; p < 0.001), abdomen/pelvis/trunk/thorax tumors (HR, 1.31; 95% CI, 1.1-1.6; p = 0.006), and distant metastases at presentation (HR, 2.6; 95% CI, 2.1-3.3; p < 0.001) negatively influenced DSS. Conclusions: Radiation and surgery positively influence survival in high-grade SLMS while chemotherapy appears to have no benefit. Surgery alone appears to lower the mortality risk in PLB.

Survival and outcomes of modular endoprosthetic reconstruction of the proximal femur for primary and non-primary bone tumors: Single institutional results

Purpose

This study assessed implant survival and dislocation following proximal femur tumor endoprosthetic replacement.

Methods

Thirty-eight procedures were performed between 2005 and 2019. The cumulative incidence of implant revision was calculated with death as a competing risk.

Results

The majority of endoprostheses were bipolar hemiarthroplasty (n = 33, 86.8%). The cumulative incidence of revision was 14.6% (95% CI, 3.2%-34.1%) at five years. Dislocation occurred in 7.9% (n = 3) of hips at a mean (SD) 44 ± 35.2 days.

Conclusions

Proximal femur tumor endoprosthetic replacement is a durable option that tends to outlive patients. Strict postoperative bracing may lower dislocation rates.

Level of evidence

III. Retrospective Study.

Epithelioid hemangioendothelioma of bone: A survival analysis of 50 cases from the SEER database (1992-2016)

Epithelioid hemangioendothelioma (EHE) is a rare vascular tumor that may arise in bone. The purpose of this investigation was to determine the clinicopathological features and outcomes of osseous EHE in a large patient series, and to assess whether survival is impacted by demographics, tumor characteristics, or treatment factors. This was a retrospective review of the Surveillance, Epidemiology and End Results (SEER) database from 1992 to 2016. Kaplan-Meier was used to estimate overall survival (OS) and disease-specific survival (DSS). A Cox regression model was used to identify prognostic factors. Fifty patients from 1992 to 2016 with a median age of 54.5 years (IQR, 37–67) were reviewed. For location, 46% (n = 23) of tumors arose from the appendicular skeleton while 38% (n = 19) occurred within the axial skeleton (overlapping EHE: 16%, n = 8). Of the cases with recorded treatment factors, 54.8% (n = 23) had surgery, 26% (n = 13) received radiation, 22% (n = 11) were treated with chemotherapy, and 26% (n = 13) had surgery plus radiation. The 5-year OS probability was 49.2% (95% CI, 23.6–70.6), and the 5-year DSS probability was 63.9% (95% CI, 33.0–83.5). No surgery (surgery: HR, 0.262; 95% CI, 0.07–0.9); p = 0.041) and age older than 50 years (HR, 4.117; 95% CI, 1.1–15.4; p = 0.035) were negative prognostic factors of disease-specific mortality after controlling for confounding variables. There was no association between disease-specific mortality and adjuvant or multimodal therapy. The prognosis of EHE of bone is less than favorable, and the 5-year DSS probability of 64% emphasizes the intermediate grade nature of this tumor subtype. Surgical treatment, when feasible, is associated with a better prognosis.

The prognostic significance of lymphovascular tumor invasion in localized high-grade osteosarcoma: Outcomes of a single institution over 10 years

BACKGROUNDS AND OBJECTIVES

Lymphovascular invasion (LVI) has shown evidence of an association with worse survival in high-grade osteosarcoma patients. The purpose of this investigation was to prognosticate LVI as a predictor of survival.

METHODS

This was a retrospective review of high-grade, localized osteosarcoma patients over a consecutive 10-year period. Proportional hazards regression was used to identify prognostic factors. Cumulative mortality incidence was estimated with recurrence as a competing risk.

RESULTS

Forty-two cases with a median follow-up of 64 months (range, 6-158 months) were reviewed. LVI was present in 21.4% (n = 9) cases. The five- and ten-year survivals in LVI (+) were 40% and 20%, compared to 93% and 81% in LVI (-), respectively (p < .001). After controlling for confounders, advanced age (hazards ratio [HR], 1.134; 95% confidence interval [CI], 1-1.2; p = .01) and LVI (HR, 21.768; 95% CI, 3-135; p = .001) were negative prognosticators. The cumulative incidence of recurrence was no different between LVI (+) and LVI (-) (p = .811), though the incidence of mortality was significantly higher in LVI (+) (p = .003).

CONCLUSION

The presence of LVI in the setting of high-grade, localized osteosarcoma is associated with greater rates of mortality and appears to portend a dismal prognosis.

A Population-based Analysis of Lymph Node Metastasis in Extremity Soft Tissue Sarcoma: An Update

BACKGROUND

Soft tissue sarcomas (STSs) are mesenchymal tumors that may rarely metastasize to lymph nodes. This investigation sought to evaluate regional lymph node metastasis (RLNM) in extremity STS using a national cohort.

MATERIALS AND METHODS

This study was a retrospective review of the Surveillance, Epidemiology, and End Results database from 1975 to 2016. A Cox proportional hazards model was used to identify prognostic factors associated with disease-specific survival (DSS).

RESULTS

RLNM was present in 3.7% (n = 547) of extremity STS. The rate of RLNM was highest in rhabdomyosarcoma (26.7%), clear cell sarcoma (18.8%), epithelioid sarcoma (14.5%), angiosarcoma (8.1%), spindle cell sarcoma (5.0%), and synovial sarcoma (3.2%). The 5-year DSS probability without RLNM was 69% (standard error: 1.3%) compared to 26% (standard error: 3.6%) with RLNM (P < 0.001). For the historically high-risk extremity STS, advanced age (hazard ratio (HR), 1.036; 95% confidence interval (CI), 1.0-1.04; P < 0.001), higher grade tumors (HR, 1.979; 95% CI, 1.3-3.0; P < 0.001), tumor size greater than 10 cm (HR, 1.892; 95% CI, 1.3-2.7; P < 0.001), primary site surgery (HR, 0.529; 95% CI, 0.3-0.8; P = 0.006), distant metastasis (HR, 4.585; 95% CI, 3.0-6.8; P < 0.001), and RLNM (HR, 2.153; 95% CI, 1.3-3.5; P = 0.003) were each independent disease-specific prognostic factors.

CONCLUSIONS

The prognosis of RLNM in historically high-risk extremity STS is poor with a 5-year DSS of 26%. These data support a staging system of STS inclusive of nodal involvement and contribute to the growing body of evidence that characterizes the rates of RLNM in STS.

Comparison of clinicopathological features and outcomes in patients with primary leiomyosarcoma of bone and soft tissue

BACKGROUNDS AND OBJECTIVES

This investigation sought to describe the outcomes of primary leiomyosarcoma of bone (PLB) compared to soft tissue leiomyosarcoma (SLMS).

METHODS

This was a review of the Surveillance, Epidemiology, and End Results database from 1975 to 2016. Kaplan-Meier methods were used to estimate disease-specific survival (DSS), and a Cox regression model was used to identify prognostic factors.

RESULTS

Of the 7502 identifiable cases, 1% (n = 74) were PLB and 99% (n = 7428) were SLMS. Survival was the same between PLB and SLMS (p = .209). On multivariable analysis for high-grade SLMS, radiation (neoadjuvant: hazard ratio [HR], 0.56; 95% confidence interval [CI], 0.4-0.8; p = .003; adjuvant: HR, 0.75; 95% CI, 0.6-0.9; p = .008) and surgery (procedure specific) improved DSS. For PLB, wide resection/limb salvage (HR, 0.40; 95% CI, 0.3-0.5; p = .018) and amputation (HR, 0.69; 95% CI, 0.5-0.9; p < .001) were positive prognostic factors. Neither radiation nor chemotherapy were prognostic factors for survival in PLB.

CONCLUSIONS

For SLMS, radiation portends a survival advantage. For PLB, however, neither chemotherapy nor radiation were significant prognostic factors, which suggests the optimal treatment for PLB, similar to other primary soft tissue sarcomas originating in bone, remains an unmet medical need.

A single institutional experience treating adipocytic tumors: incidence, disease-related outcomes, and the clinical significance of MDM2 analysis

Adipocytic tumors exist either as a benign or malignant form. The benign variant, lipoma, is composed of normal fat tissue. Lipomas typically develop from superficial fat cells beneath the skin or mucous membranes. Liposarcoma, the malignant counterpart, often develops in deeper tissues and is the most commonly diagnosed Soft Tissue Sarcoma (STS), comprising at least 20% of adult STS. However, malignant tumors of fatty origin exist as a spectrum of diagnoses, each carrying a unique risk of recurrence, metastasis, and longterm survival. The World Health Organization classifies liposarcomas into five categories: i) Atypical Lipomatous Tumors/Well Differentiated (ALT/WD); Ii) Dedifferentiated (ALT/DD); Iii) Myxoid; Iv) Round cell; and v) Pleomorphic. Lipomatous tumors often exhibit different immunohistochemical patterns. Benign lipomas are distinguished by the absence of Murine Double-Minute 2 (MDM2) amplification. Similarly, ALT/WD, classically defined as a low-grade and locally aggressive tumor, demonstrates consistent patterns of MDM2 amplification. Some studies suggest 10% of ALT/WD progress to the highgrade DD form, with others report a dedifferentiation rate of as high as 20% for primary ALT/WD based on location. The ALT/DD subtype is aggressive and has a high capacity to metastasize. While the mechanism of pathogenesis of ALT/DD metastasis is unknown, previous studies suggest that increased MDM2 amplification may play a role. This study sought to evaluate a single institutional experience treating the entire spectrum of lipomatous tumors and describe utilization patterns of MDM2 testing. The group hypothesized: i) Atypical Lipomatous Tumors (ALT), which include ALT/DD and ALT/WD, would exhibit a higher rate of local recurrence than lipomas with no significantly increased incidence of metastases; and ii) at least 50% of our MDM2 testing of ALT would prove positive for the MDM2 overamplification. This study retrospectively reviewed 105 cases (66 lipomas, 27 ALTs, 12 liposarcomas) of patients who underwent lipomatous tumor excision at our institution from 2013 to 2017. Twenty-five tumors (6 lipomas, 18 ALT, 1 liposarcoma) were tested for MDM2 amplification. Three of the tested tumors recurred (2 ALT, 1 liposarcoma), and each exhibited MDM2 overamplification. Five tumors (5 liposarcoma) developed late metastases. These data suggest that although ALT is associated with a higher rate of local recurrence, metastases are quite rare. Additionally, the data demonstrate a high rate of positive MDM2 testing (76%) based on clinical and imaging characteristics of the tumors.

A clinicopathologic examination of myxofibrosarcoma. Do surgical margins significantly affect local recurrence rates in this infiltrative sarcoma subtype?

BACKGROUND AND OBJECTIVES

Myxofibrosarcoma (MFS) is an aggressive soft tissue tumor with an unpredictable recurrence pattern. We sought to (a) determine whether margin status in MFS is correlated to rates of local recurrence (LR) and (b) identify demographic and treatment variables associated with disease-related outcomes in this population.

METHODS

This retrospective study identified 42 surgically treated patients with MFS over 10 years at a single institution. Patient demographics, tumor characteristics, intraoperative variables, and disease-related outcomes were recorded.

RESULTS

Thirty-three (83%) patients had negative surgical margins and seven (18%) had positive margins. Four of 32 patients (13%) with negative margins developed subsequent LR compared to six of seven (86%) patients with positive margins (p < .001). Three patients (75%) with metastatic disease were deceased at the end of the study, while five (15%) without metastasis were deceased (p = .024).

CONCLUSIONS

Positive margin procedures for MFS were associated with LR. However, negative surgical margins demonstrated a relatively high rate of LR compared to other soft tissue sarcoma subtypes. Furthermore, though MFS tends to locally recur and have a propensity for distant metastasis, patients are observed to have a higher probability of death from other causes.

Pelvic ring reconstruction with segmental spinal instrumentation after complete type I pelvic resection

BACKGROUND AND OBJECTIVES

Internal hemipelvectomy is a complex procedure used to treat malignancy that involves the pelvis. Reconstruction of the pelvis after type I or type I/IV resection remains controversial due to high complication rates and debatable functional benefit. Modern reconstruction options may provide a rapid, intuitive, and reliable way to reconstitute the pelvic ring.

METHODS

This is a retrospective case series of four patients who underwent a novel reconstruction method involving computer navigation and segmental spinal instrumentation applied to the pelvis after type I or type I/IV pelvic resection for malignancy between 2015 and 2020.

RESULTS

Time to ambulation postoperatively ranged from 1 to 7 days, and median length of hospital stay was 8.5 (7.5, 10.5) days. Complications included wound necrosis in two patients that did not require reoperation and wound infection in one patient that required irrigation and debridement. There was no radiographic evidence of hardware loosening or failure on follow-up. Three patients remain alive and two remain disease-free. At most recent follow-up, all patients were able to ambulate and perform activities of daily living.

CONCLUSIONS

The technique for pelvic reconstruction described allows for rapid fixation intraoperatively with few complications and satisfactory functional results in this limited series.

Clinical benefit of next generation sequencing in soft tissue and bone sarcoma: Rush University Medical Center’s experience

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Background: The overall survival for metastatic sarcoma has remained at only 18-20%. In the era of next generation sequencing (NGS), much research is ongoing on identifying optimal treatments. The MULTISARC trial aims to determine if NGS can lead to improved overall survival by randomizing patients with metastatic STS to receive NGS (followed by possible NGS-guided therapy) or not. We present our center’s experience with NGS in sarcomas patients. Methods: Patients with soft tissue and bone sarcomas at Rush that had the Foundation Medicine assay sent on tumor samples between August 2017 and August 2018 were analyzed retrospectively. The impact of NGS on clinical decision making was determined based on patients being prescribed off-label FDA-approved therapy targeting identified mutation. Results: Thirty-four patients with bone/soft tissue sarcomas that had NGS sent on specimens were identified. Median age at diagnosis: 43 (18-78 years); 18 males, 16 females. Histologic subtypes: synovial sarcoma, myxofibrosarcoma, leiomyosarcoma, chondrosarcoma, sclerosing epitheloid fibrosarcoma, PEcoma, pleomorphic undifferentiated sarcoma, MPNST, liposarcoma- well and de-differentiated, angiosarcoma, osteosarcoma. 16/34 patients had targetable mutations with approved therapies in tumor types other than sarcoma. Four of these patients had therapy changed based on NGS results, 1 patient with metastatic chondrosarcoma (PTEN mutation, everolimus added), 1 patient with metastatic liposarcoma (CDK4 mutation, palbociclib added), 1 patient with metastatic osteosarcoma (CCD1/CDK4 and a PDGFRA mutation for which palbociclib followed by imatinib was added), and 1 patient with metastatic pleomorphic undifferentiated sarcoma (CDK4 mutation, palbociclib added). Targetable mutations for which clinical trials are available were identified in 25/34 (73%) of the cases. Conclusions: NGS was readily able to identify actionable mutations in close to 50% of patients with clinical trial opportunities in close to 75%. Four patients had therapy changed as a result of NGS testing. Although our study size is small, our data show potential for the use of genomic profiling to identify actionable targets, tailor therapy, and hopefully improve outcomes. [Table: see text]

Treatment of soft tissue sarcoma with a novel cold plasma jet

e22562

Background: Soft tissue sarcoma is a malignant tumor that most often develops in adults, but can occur in children as well. Treatment with radiation, en bloc surgical resection and chemotherapy have achieved long-term survival rates up to 65% to 80% in non-metastatic disease. Local microscopic tumor cells can still exist despite complete R-0 surgical excision of the tumor. A novel technology Cold Atmospheric plasma (CAP) is an emerging technology that has shown promising anticancer effects i.e anti-mitotic and less effective on non-cancerous tissue. A new field has developed in medicine Plasma Onco-therapeutics. CAP treatment has the potential to improve the outcome of osteosarcoma patients. Methods: CAP was generated using a US Medical Innovations LLC (USMI) SS-601 MCa high-frequency electrosurgical generator (USMI, Takoma Park, MD, USA) integrated with Canady Cold Plasma Conversion Unit and connected to a Canady Helios Cold Plasma Scalpel. Three types of human sarcoma cells, synovial sarcoma (SW982), connective tissue fibro sarcoma (HT-1080), and rhabdomyosarcoma (RD) were used in this study to test the effect of the CAP generated by the Canady Cold Plasma Conversion System. Cells were treated with various CAP settings including different helium flow rates (1 and 3 LPM) and power settings (20-120p) in order to establish an optimal treatment condition for each cell line. Viability was performed on the cells using MTT assay 48 hours after CAP treatment. Student t test was performed on the data (*p < 0.05). Results: The reduction of the viability of all three sarcomas were dose-dependent and significantly reduced at various time and power combinations tested (Figure 1-3). Helium flow alone did not significantly impact cell viability. The decrease in viability of the sarcoma cells when using 1 LPM required a higher dose. About 20 to 40% of viability reduction was seen on the three cell lines. With 3LPM, viability was reduced to 20% using 80p 2 min for SW982 and HT-1080, and 100p 2min for RD. Conclusions: Our data demonstrates that CAP reduced sarcoma cell viability in a time- and power-dependent manner. With optimal dosage for each cancer type, this study provides a promising treatment for future therapeutic interventions for soft tissue sarcomas.

Crosstalk between the IGF-1R/AKT/mTORC1 pathway and the tumor suppressors p53 and p27 determines cisplatin sensitivity and limits the effectiveness of an IGF-1R pathway inhibitor

The insulin-like growth factor-1 receptor (IGF-1R) signaling pathway is aberrantly activated in multiple cancers and can promote proliferation and chemotherapy resistance. Multiple IGF-1R inhibitors have been developed as potential therapeutics. However, these inhibitors have failed to increase patient survival when given alone or in combination with chemotherapy agents. The reason(s) for the disappointing clinical effect of these inhibitors is not fully understood. Cisplatin (CP) activated the IGF-1R/AKT/mTORC1 pathway and stabilized p53 in osteosarcoma (OS) cells. p53 knockdown reduced IGF-1R/AKT/mTORC1 activation by CP, and IGF-1R inhibition reduced the accumulation of p53. These data demonstrate positive crosstalk between p53 and the IGF-1R/AKT/mTORC1 pathway in response to CP. Further studies showed the effect of IGF-1R inhibition on CP response is dependent on p53 status. In p53 wild-type cells treated with CP, IGF-1R inhibition increased p53s apoptotic function but reduced p53-dependent senescence, and had no effect on long term survival. In contrast, in p53-null/knockdown cells, IGF-1R inhibition reduced apoptosis in response to CP and increased long term survival. These effects were due to p27 since IGF-1R inhibition stabilized p27 in CP-treated cells, and p27 depletion restored apoptosis and reduced long term survival. Together, the results demonstrate 1) p53 expression determines the effect of IGF-1R inhibition on cancer cell CP response, and 2) crosstalk between the IGF-1R/AKT/mTORC1 pathway and p53 and p27 can reduce cancer cell responsiveness to chemotherapy and may ultimately limit the effectiveness of IGF-1R pathway inhibitors in the clinic.

The IGF-1R/AKT pathway has opposing effects on Nutlin-3a-induced apoptosis

Nutlin-3a is a small molecule MDM2 antagonist and potent activator of wild-type p53. Nutlin-3a disrupts MDM2 binding to p53, thus increasing p53 levels and allowing p53 to inhibit proliferation or induce cell death. Factors that control sensitivity to Nutlin-3a-induced apoptosis are incompletely understood. In this study we isolated cisplatin-resistant clones from MHM cells, an MDM2-amplified and p53 wild-type osteosarcoma cell line. Cisplatin resistance in these clones resulted in part from heightened activation of the IGF-1R/AKT pathway. Interestingly, these cisplatin resistant clones showed hyper-sensitivity to Nutlin-3a induced apoptosis. Increased Nutlin-3a sensitivity was associated with reduced authophagy flux and a greater increase in p53 levels in response to Nutlin-3a treatment. IGF-1R and AKT inhibitors further increased apoptosis by Nutlin-3a in parental MHM cells and the cisplatin-resistant clones, confirming IGF-1R/AKT signaling promotes apoptosis resistance. However, IGF-1R and AKT inhibitors also reduced p53 accumulation in Nutlin-3a treated cells and increased autophagy flux, which we showed can promote apoptosis resistance. We conclude the IGF-1R/AKT pathway has opposing effects on Nutlin-3a-induced apoptosis. First, it can inhibit apoptosis, consistent with its well-established role as a survival-signaling pathway. Second, it can enhance Nutlin-3a induced apoptosis through a combination of maintaining p53 levels and inhibiting pro-survival autophagy.

Bone Grafts, Substitutes, and Augments in Benign Orthopaedic Conditions Current Concepts

Musculoskeletal tumors are relatively rare diagnoses made by orthopaedic surgeons. While approximately 2,500 primary bone sarcomas are diagnosed annually in the USA, the number of benign orthopaedic tumors encountered annually is far more difficult to quantify. Some studies have documented between 3% and 10% of the general population having benign bony lesions. Many of these conditions can be simply observed, while others will require surgical intervention. Surgical treatments for benign conditions range from a one-step curettage to extensive resection and reconstruction. With treatment of larger lesions, significant bony defects may need to be addressed surgically. Treatment options have evolved over time with the use of various bone graft and bone void fillers, including methyl methacrylate cement, autograft, allograft bone chips, struts and osteoarticular segments, synthetic bone graft substitutes, and metal augments. This review provides an overview of the present status of bone graft, substitutes, and augment options for the orthopaedic surgeon treating benign musculoskeletal conditions.

Intraoperative Ultrasound Guidance for the Removal of Nonmetallic Foreign Body from the Foot

Ultrasound has become an increasingly valuable diagnostic tool throughout all areas of medicine. The role of diagnostic ultrasonography has an evolving role in orthopaedic surgery and particularly in the field of foot and ankle. Whether in the clinic or hospital setting, ultrasound has proven to be pivotal in the identification and localization of foreign bodies. The inherent limitations of plain films in identifying nonmetallic penetrating foreign bodies of the foot can be overcome or enhanced with the assistance of diagnostic ultrasound.

LEVELS OF EVIDENCE

Therapeutic, Level IV: Case report.

A Novel Complication of the Dall-Miles Cable Grip System Mimicking Recurrent Synovial Chondromatosis: A Case Report and Review of the Literature

CASE

A 25-year-old man with synovial chondromatosis of the hip was treated with a synovectomy through a transtrochanteric approach; the repair was made with use of a Dall-Miles cable. Approximately 13 years later, the patient returned with a massive bursal reaction and a cyst containing "rice bodies." Although the physical examination and imaging were suggestive of recurrent synovial chondromatosis, the bursal reaction actually represented a novel complication of the Dall-Miles system.

CONCLUSION

When a patient who has had prior orthopaedic instrumentation presents with pain and imaging that demonstrates formation of a bursal cyst, a cyst containing rice bodies secondary to bursal irritation by the implant should be considered.

Acetabular Osteoarticular Allograft After Ewing Sarcoma Resection: A 15-Year Follow-up: A Case Report

CASE

A 4-year-old girl with Ewing sarcoma of the periacetabular region had been treated with neoadjuvant chemotherapy followed by resection and osteoarticular allograft reconstruction with an adult hemipelvis. At 15 years postoperatively, she remained disease-free with remarkable functionality. She had minimal groin pain and could walk an unlimited distance. Radiographs demonstrated union at the anastomotic junctions. The allograft, which had been considerably oversized 15 years ago, was now identical in size to the contralateral ilium.

CONCLUSION

Osteoarticular allograft remains one of the best reconstructive options following hemipelvectomy in the pediatric population because of its potential durability and its capacity to restore pelvic stability and preserve functionality.

Bioceramic bone graft substitute for treatment of unicameral bone cysts

PURPOSE

To review the outcome of 12 patients who underwent debridement and injection of bioceramic for unicameral bone cyst (UBC). The resorption rate of the bioceramic was estimated by both traditional and novel methods.

METHODS

Records of 10 males and 2 females aged 6 to 34 years who underwent debridement and injection of bioceramic for UBC and were followed up for a mean of 41 (range, 26-57) months were reviewed. Functional outcome was assessed using the selfcompleted Musculoskeletal Tumor Society (MSTS) questionnaire. Radiological outcome was assessed using both original and modified Neer Outcome Rating System. The resorption rate of the bioceramic was estimated using both traditional and novel (ImageJ) methods.

RESULTS

The mean MSTS score was 29.7 (range, 28-30) indicating excellent functional outcome. Of the 12 patients, 9 achieved complete healing and 3 had a residual cyst of 1%, 11%, and 52%. The last was considered a local recurrence, and the patient underwent repeat percutaneous injection of the bioceramic 1.5 years later and remained disease-free 4 years later. The mean resorption rate was 29% faster when estimated using the traditional rather than the ImageJ method (0.47 vs. 0.33 cm3/day, p=0.02). In the patient with recurrence, the resorption rate was faster than the average (0.68 vs. 0.33 cm3/day).

CONCLUSION

A single percutaneous injection of the bioceramic for UBC achieved good functional and radiological outcome while avoiding donor-site morbidity.