Prediction of 5-year survival in soft tissue leiomyosarcoma using a machine learning model algorithm

BACKGROUND AND OBJECTIVES

Leiomyosarcoma (LMS) is associated with one of the poorest overall survivals among soft tissue sarcomas. We sought to develop and externally validate a model for 5-year survival prediction in patients with appendicular or truncal LMS using machine learning algorithms.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was used for development and internal validation of the models; external validation was assessed using our institutional database. Five machine learning algorithms were developed and then tested on our institutional database. Area under the receiver operating characteristic curve (AUC) and Brier score were used to assess model performance.

RESULTS

A total of 2209 patients from the SEER database and 81 patients from our tertiary institution were included. All models had excellent calibration with AUC 0.84-0.85 and Brier score 0.15-0.16. After assessing the performance indicators according to the TRIPOD model, we found that the Elastic-Net Penalized Logistic Regression outperformed other models. The AUCs of the institutional data were 0.83 (imputed) and 0.85 (complete-case analysis) with a Brier score of 0.16.

CONCLUSION

Our study successfully developed five machine learning algorithms to assess 5-year survival in patients with LMS. The Elastic-Net Penalized Logistic Regression retained performance upon external validation with an AUC of 0.85 and Brier score of 0.15.

Debridement, Antibiotics, and Implant Retention (DAIR) Plus Offers Similar Periprosthetic Joint Infection Treatment Success Rates to Two-Stage Revision in Oncologic Megaprosthesis

BACKGROUND

Prosthetic joint infections (PJIs) after megaprosthesis implantation are associated with high rates of treatment failure and amputation. Our study analyzed PJI treatment success rates by surgical strategy and assessed risks of reinfection and amputation.

METHODS

We retrospectively analyzed the outcomes of patients diagnosed with PJI after undergoing megaprosthesis implantation for oncologic indications. The 2011 Musculoskeletal Infection Society criteria were used to define PJI. Reinfection, reoperation, and amputation for PJI recurrence were assessed. A total of 67 patients with megaprosthesis PJIs were included. There were fourteen patients who were treated with debridement, antibiotics, and implant retention (DAIR), 31 with DAIR plus (DAIR with modular component exchange and stem retention), and 21 with two-stage revisions. Kaplan-Meier estimates were used for survival analyses and Cox proportional hazards for risk factor analyses.

RESULTS

The two-year reinfection-free survival was 25% for DAIR and 60% for DAIR plus or two-stage revision (P = .049). The five-year amputation-free survival was 84% for DAIR plus or two-stage revision, and 48% for DAIR (P = .13). Reinfection-free, reoperation-free, and amputation-free survival were similar between DAIR plus and two-stage revision at the 2- and 5-year marks. Body mass index ≥30 (hazard ratio [HR] = 2.65) and chronic kidney disease (HR = 11.53) were risk factors for reinfection. Treatment with DAIR plus or two-stage revision (HR = 0.44) was a protective factor against reinfection.

CONCLUSIONS

A DAIR was associated with high rates of treatment failure and higher amputation rates than DAIR plus or 2-stage surgery. A DAIR plus was not inferior to 2-stage revision clearing a PJI and might be performed in patients who cannot withstand two-stage revision surgery.

What Are the Functional and Surgical Outcomes of Tibial Turnup-plasty for Salvage in Patients With Chronic Lower Extremity Infection?

BACKGROUND

Tibial turnup-plasty is a rarely performed surgical option for large bone defects of the distal or entire femur and can serve as an alternative to hip disarticulation or high above-knee amputation. It entails pedicled transport of the ipsilateral tibia with or without the proximal hindfoot for use as a vascularized autograft. It is rotated 180° in the coronal or sagittal plane to the remaining proximal femur or pelvis, augmenting the functional length of the thigh. Prior reports consist of small case series with heterogeneous surgical techniques. Patient-reported outcome measures after the procedure have not been reported, and ambulatory status after the procedure is also unknown.

QUESTIONS/PURPOSES

(1) What proportion of patients underwent reoperation after tibial turnup-plasty? (2) What is the ambulatory status and what proportion of patients used a prosthesis after tibial turnup-plasty? (3) What are the Patient-Reported Outcome Measurement Information System (PROMIS) Global-10 mental and physical function scores after tibial turnup-plasty?

METHODS

A retrospective analysis was performed of 11 patients who underwent tibial turnup-plasty between 2003 and 2021 by a single orthopaedic oncology division in collaboration with a reconstructive plastic surgery team. Nine patients were men, with a median age of 55 years (range 34 to 75 years). All had chronic infections after arthroplasty or oncologic reconstructions, with a median number of 13 surgeries before turnup-plasty. All were considered to have no other surgical options other than hip disarticulation or high transfemoral amputation. All patients who were offered this possibility accepted it. Data of interest included patient demographics and comorbidities, surgical history that led to limb compromise, medical and surgical perioperative complications, date of prosthesis fitting, and functional capacity at the most recent follow-up interval based on ambulatory status and PROMIS Global-10 mental and physical function scores. The statistical analysis was descriptive.

RESULTS

The median number of reoperations after turnup-plasty was one (range 0 to 11). Of the six patients who underwent at least one reoperation, indications for surgery included wound infection (four patients), nonunion of the osteosynthesis site (two), heterotopic ossification (one), tumor recurrence (one), and flap hypoperfusion treated with local tissue revision (one). One patient underwent conversion to external hemipelvectomy for tumor recurrence. Ten of the 11 patients were ambulatory at the final follow-up interval with standard above-knee amputation prostheses. Two ambulated unassisted, four used a single crutch or cane, and four used two crutches or a walker. Of the nine patients for whom scores were available, the median PROMIS Global-10 physical and mental health scores were 48 (range 30 to 68) and 53 (range 41 to 68), both within the standard deviation of the population mean of 50.

CONCLUSION

The tibial turnup-plasty is a complex surgical option for patients with large bone defects of the femur for whom there are no alternative surgeries capable of producing residual extremities with acceptable functional length. This should be viewed as a procedure of last resort to avoid a hip disarticulation or a high transfemoral amputation in patients who have typically undergone numerous prior operations. Although ambulation with a prosthesis within 1 year can be expected, almost all patients will require an assistive device to do so, and reoperations are frequent.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Metastatic Uterine Leiomyosarcoma With Rhabdomyosarcomatous Heterologous Differentiation

Heterologous differentiation has only been previously reported twice in metastatic uterine leiomyosarcomas. We report herein the first case of metastatic uterine leiomyosarcoma with rhabdomyosarcomatous differentiation. A 67-yr-old woman presented with femur, abductor magnus, and lymph node metastases 9 yr after the primary diagnosis. The metastatic sites showed rhabdomyosarcomatous morphologic features, and immunohistochemical studies confirmed skeletal muscle differentiation. Molecular testing revealed the same loss-of-function TP53 mutation in the uterine leiomyosarcoma and metastatic sites supporting heterologous differentiation of the primary tumor. Our case highlights the morphologic shifts metastatic tumors may manifest and the potential diagnostic problems that may arise.

Prognostic Significance of Percentage and Size of Dedifferentiation in Dedifferentiated Chondrosarcoma

Dedifferentiated chondrosarcoma is rare, aggressive, and microscopically bimorphic. How pathologic features such as the amounts of dedifferentiation affect prognosis remains unclear. We evaluated the percentages and sizes of dedifferentiation in a consecutive institutional series of dedifferentiated chondrosarcomas from 1999 to 2021. The statistical analysis included cox proportional hazard models and log-rank tests. Of the 67 patients (26 women, 41 men; age, 39 to >89 [median 61] years; 2 with Ollier disease), 58 presented de novo; 9 were identified with conventional chondrosarcomas 0.6-13.2 years (median, 5.5 years) prior. Pathologic fracture and distant metastases were noted in 27 and 7 patients at presentation. The tumors involved the femur (n = 27), pelvis (n = 22), humerus (n = 7), tibia (n = 4), scapula/ribs (n = 4), spine (n = 2), and clivus (n = 1). In the 56 resections, the tumors ranged in size from 3.5 to 46.0 cm (median, 11.5 cm) and contained 1%-99.5% (median, 70%) dedifferentiated components that ranged in size from 0.6 to 24.0 cm (median, 7.3 cm). No correlation was noted between total size and percentage of dedifferentiation. The dedifferentiated components were typically fibrosarcomatous or osteosarcomatous, whereas the associated cartilaginous components were predominantly grade 1-2, rarely enchondromas or grade 3. The entire cohort's median overall survival and progression-free survival were 11.8 and 5.4 months, respectively. In the resected cohort, although the total size was not prognostic, the percentage of dedifferentiation ≥20% and size of dedifferentiation >3.0 cm each predicted worse overall survival (9.9 vs 72.5 months; HR, 3.76; 95% CI, 1.27-11.14; P = .02; 8.7 vs 58.9 months; HR, 3.03; 95% CI, 1.21-7.57; P = .02, respectively) and progression-free survival (5.3 vs 62.1 months; HR, 3.05; 95% CI, 1.13-8.28; P = .03; 5.3 vs 56.6 months; HR, 2.50; 95% CI, 1.06-5.88; P = .04, respectively). In conclusion, both the percentages and sizes of dedifferentiation were better prognostic predictors than total tumor sizes in dedifferentiated chondrosarcomas, highlighting the utility of their pathologic evaluations.

The impact of radiotherapy on survival after surgical resection of chordoma with minimum five-year follow-up

BACKGROUND CONTEXT

Local control remains a vexing problem in the management of chordoma despite advances in operative techniques and radiotherapy (RT) protocols. Existing studies show satisfactory local control rates with different treatment modalities. However, those studies with minimum follow-up more than 4 years demonstrate increasing rates of local failure. Therefore, mid-term local survival rates may be inadvertently elevated by studies with less than 4 years follow-up.

PURPOSE

The purpose of this study is to report the mid-term results of primary spinal chordoma treated with en bloc resection and proton-based RT with minimum 5 years of follow-up.

STUDY DESIGN/SETTING

Retrospective, single-center, cohort study.

PATIENT SAMPLE

Patients undergoing primary surgical excision of a spine or sacral chordoma tumor between 1990 and 2016 at a single-institution were included. Patients were included if they had a local failure at any time, or they had a minimum of 5 years of follow up with no local failure. Patients were excluded if a prior surgical excision was performed or metastases were present at the time of referral.

OUTCOME MEASURES

The outcome measures were local recurrence-free interval (LRFI) and overall survival (OS).

METHODS

Demographic, clinical, oncologic and surgical variables, including margin status, as well as radiation doses and schedule (neoadjuvant, adjuvant, or both) were compared using Wilcoxon rank-sum or chi-squared testing. The goal RT dose was 70 Gray (total) and patients were stratified based on completing (C70) or receiving incomplete (I70) dosing. Overall survival (OS) and local-recurrence free interval (LRFI) were calculated using the Kaplan-Meier method.

FUNDING STATEMENT

No funding was obtained for this work.

RESULTS

Seventy-six patients were included in the final analysis. All patients had a minimum of 5-year follow-up (median 9.3 years, range 5.1-24.7 years). There were no significant clinical differences between the C70 and I70 RT groups. OS was greater for the C70 RT group (5-year OS 82% vs. 63%, p=.001). There was similar OS for the positive margin group (5-year OS 70% vs. 61%, p=.266). LRFI was greater for the C70 RT group (5-year OS 93% vs. 78%, p=.017). There was similar LRFI for the positive margin group (5-year OS 90% versus 87%, p=.810).

CONCLUSION

Chordoma outcomes trend towards diminishing LRFI rates in the literature. Here we report the results of the operative management of primary spinal chordoma with minimum five year follow-up, the addition of C70 RT to surgical excision conferred a benefit to OS and local recurrence.

Comparison of carbon fibre and titanium intramedullary nails in orthopaedic oncology

Aims

Due to their radiolucency and favourable mechanical properties, carbon fibre nails may be a preferable alternative to titanium nails for oncology patients. We aim to compare the surgical characteristics and short-term results of patients who underwent intramedullary fixation with either a titanium or carbon fibre nail for pathological long-bone fracture.

Methods

This single tertiary-institutional, retrospectively matched case-control study included 72 patients who underwent prophylactic or therapeutic fixation for pathological fracture of the humerus, femur, or tibia with either a titanium (control group, n = 36) or carbon fibre (case group, n = 36) intramedullary nail between 2016 to 2020. Patients were excluded if intramedullary fixation was combined with any other surgical procedure/fixation method. Outcomes included operating time, blood loss, fluoroscopic time, and complications. Fisher’s exact test and Mann-Whitney U test were used for categorical and continuous outcomes, respectively.

Results

Patients receiving carbon nails as compared to those receiving titanium nails had higher blood loss (median 150 ml (interquartile range (IQR) 100 to 250) vs 100 ml (IQR 50 to 150); p = 0.042) and longer fluoroscopic time (median 150 seconds (IQR 114 to 182) vs 94 seconds (IQR 58 to 124); p = 0.001). Implant complications occurred in seven patients (19%) in the titanium group versus one patient (3%) in the carbon fibre group (p = 0.055). There were no notable differences between groups with regard to operating time, surgical wound infection, or survival.

Conclusion

This pilot study demonstrates a non-inferior surgical and short-term clinical profile supporting further consideration of carbon fibre nails for pathological fracture fixation in orthopaedic oncology patients. Given enhanced accommodation of imaging methods important for oncological surveillance and radiation therapy planning, as well as high tolerances to fatigue stress, carbon fibre implants possess important oncological advantages over titanium implants that merit further prospective investigation.

Level of evidence: III, Retrospective study

Cite this article: Bone Jt Open 2022;3(8):648–655.

Trabecular metal augments in severe malignancy-associated acetabular bone loss

INTRODUCTION

Acetabular reconstruction is a challenging problem in orthopaedic oncology, especially in extended defects (Paprosky Type 3A and Type 3B). In revision total hip arthroplasty (THA), 1 option is trabecular metal (TM) augments with a porous metal acetabular component. This study evaluated the use of TM augments in periacetabular malignant bone disease.

METHODS

15 patients were identified from our institutional database from 2000 to 2020 with either Paprosky Type 3A or Type 3B acetabular bone loss due to periacetabular malignancies that underwent at least 1 complex THA reconstruction with TM augments. Postoperative complications were documented, and clinical and radiographic outcomes were analysed. Radiological loosening or revision of the acetabular component were defined as endpoints.

RESULTS

There were 7 primary and 8 metastatic cancer patients. 5 were Type 3A and 10 were Type 3B defects after tumour resection. The average follow-up time was 23.8 (range 1.5-47) months. 1 patient required revision for acetabular component loosening after 7 months from the initial implantation. An additional 4 patients required surgical intervention for infection, they had stable TM augments at latest follow-up.

CONCLUSION

TM augments with a porous metal acetabular component may be an alternative to the traditional cemented constructs.

Sclerostin immunohistochemical staining in surgically treated giant cell tumor of bone

BACKGROUND

Giant cell tumor of bone (GCTB) is a destructive lesion with a high potential for recurrence. RANK-ligand targeted therapy has provided promising, yet mixed results. Sclerostin (SOST) inhibition results in a net anabolic response and is currently used in the treatment of osteoporosis. The application to GCTB is unknown.

OBJECTIVES

We sought to determine if GCTB stained for SOST on immunohistochemistry and correlate its expression with predictor variables.

METHODS

All patients at a single institution undergoing surgery for GCTB between 1993 and 2008 with a minimum of 6 months follow-up were included. Primary outcomes included the presence of SOST staining, secondary outcomes included the correlation of patient and tumor-specific predictor variables.

RESULTS

SOST antibody staining of any cell type was present in 47 of 48 cases (97.9%). Positivity of the stromal cells was present in 39 of 48 cases (81.3%) and was associated with radiographic aggressiveness (p = 0.023), symptomatic presentation (p = 0.032), prior surgery (p = 0.005), and patient age (p = 0.034). Positivity of giant cells was present in 41 of 48 cases (85.4%) and was not significant with predictive factors.

CONCLUSIONS

Sclerostin staining in GCTB is a novel finding and warrants further research to define the role of sclerostin as a prognostic factor and therapeutic target.

Clinical Outcome Differences in the Treatment of Impending Versus Completed Pathological Long-Bone Fractures

BACKGROUND

The outcome differences following surgery for an impending versus a completed pathological fracture have not been clearly defined. The purpose of the present study was to assess differences in outcomes following the surgical treatment of impending versus completed pathological fractures in patients with long-bone metastases in terms of (1) 90-day and 1-year survival and (2) intraoperative blood loss, perioperative blood transfusion, anesthesia time, duration of hospitalization, 30-day postoperative systemic complications, and reoperations.

METHODS

We retrospectively performed a matched cohort study utilizing a database of 1,064 patients who had undergone operative treatment for 462 impending and 602 completed metastatic long-bone fractures. After matching on 22 variables, including primary tumor, visceral metastases, and surgical treatment, 270 impending pathological fractures were matched to 270 completed pathological fractures. The primary outcome was assessed with the Cox proportional hazard model. The secondary outcomes were assessed with the McNemar test and the Wilcoxon signed-rank test.

RESULTS

The 90-day survival rate did not differ between the groups (HR, 1.13 [95% CI, 0.81 to 1.56]; p = 0.48), but the 1-year survival rate was worse for completed pathological fractures (46% versus 38%) (HR, 1.28 [95% CI, 1.02 to 1.61]; p = 0.03). With regard to secondary outcomes, completed pathological fractures were associated with higher intraoperative estimated blood loss (p = 0.03), a higher rate of perioperative blood transfusions (p = 0.01), longer anesthesia time (p = 0.04), and more reoperations (OR, 2.50 [95% CI, 1.92 to 7.86]; p = 0.03); no differences were found in terms of the rate of 30-day postoperative complications or the duration of hospitalization.

CONCLUSIONS

Patients undergoing surgery for impending pathological fractures had lower 1-year mortality rates and better secondary outcomes as compared with patients undergoing surgery for completed pathological fractures when accounting for 22 covariates through propensity matching. Patients with an impending pathological fracture appear to benefit from prophylactic stabilization as stabilizing a completed pathological fracture seems to be associated with increased mortality, blood loss, rate of blood transfusions, duration of surgery, and reoperation risk.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Primary and Metastatic Bone Tumors of the Patella: Literature Review and Institutional Experience

BACKGROUND

Patellar tumors are rare but certainly must be considered in the differential diagnosis in patients with knee pain. Diagnosis can be challenging as often patellar neoplasms are confused with benign conditions and their clinical presentation is usually not specific. We performed an institutional and a literature review to determine what are the most common tumors affecting the patella and what is the best management.

METHODS

This is a case series from our institution including all patients with benign, malignant, and metastatic patellar neoplasms. Charts were reviewed for patient demographics, clinical presentation, pathology characteristics, radiographic classification, and oncologic and functional outcomes.

RESULTS

Twenty-four patients were identified; twelve patients had benign lesions, 10 metastatic and 2 primary malignant tumors. Chondroblastoma and Giant Cell Tumor were the most common tumors. Management of benign lesions with intralesional curettage and packing with bone graft or cement demonstrated excellent results with no local recurrence. In terms of malignant tumors, the spectrum of treatment is variable; it could range from medical management alone or in combination with surgical procedures to total patellectomy with reconstruction of the extensor mechanism.

CONCLUSION

Patellar tumors should be part of the differential in patients with chronic knee pain that does not respond to initial conservative interventions. Recurrence rate with intralesional curettage and bone grafting or cement packing is very low and therefore should be the treatment of choice for benign intraosseous neoplasms. Resection with negative margins in malignant neoplasms or bone metastasis decreases local recurrence but only in the former group there is a potential impact in survival.

Tubercle-Sparing Proximal Tibial Reconstruction in Patients with Primary and Metastatic Bone Disease: A Case Report

CASE

Two patients with cancer involving their proximal tibia required proximal tibial replacement (PTR). One had a soft-tissue sarcoma that involved her posterior cortex, and the other had extensive metaphyseal destruction from metastatic breast cancer. Their anterolateral cortex and tibial tubercle were uninvolved, permitting tubercle-sparing PTR. A plate was applied to the bone bridge in the latter patient in anticipation of radiotherapy. Both healed uneventfully and had minimal extensor lag 2 weeks postoperatively.

CONCLUSION

Tubercle-sparing PTR preserves extensor mechanism function with minimal lag. It should be considered in patients with cancer when sparing the anterolateral cortex is oncologically safe.

Tumors and Tumorlike Conditions of Which Every Orthopaedic Surgeon Should Be Aware

All orthopaedic surgeons during the course of their career will likely encounter both benign and malignant musculoskeletal neoplasms. Given the rarity of these entities and the stress conferred by diagnosing a tumor or tumorlike condition, many orthopaedic surgeons may benefit from a review of the contemporary treatment of such patients. Whether in the outpatient clinic or following a high-energy trauma, special attention should be given to concerning signs and symptoms that will aid in the workup of children and adults with a possible tumor. A thorough and logical workup in this manner will often lead to a definitive diagnosis such as metastatic bone disease or perhaps a benign lesion. In these instances, the informed general orthopaedic surgeon or subspecialist may choose to treat the patient independently. However, if the workup is inconclusive or if the diagnosis is even questionably malignant, referral to an orthopaedic oncologist should be sought as to avoid pitfalls in diagnosis and treatment.

Assessing the Safety and Utility of Wound VAC Temporization of the Sarcoma or Benign Aggressive Tumor Bed Until Final Margins Are Achieved

BACKGROUND

Local recurrence of microinvasive sarcoma or benign aggressive pathologies can be limb- and life-threatening. Although frozen pathology is reliable, tumor microinvasion can be subtle or missed, having an impact on surgical margins and postoperative radiation planning. The authors' service has begun to temporize the tumor bed after primary tumor excision with a wound vacuum-assisted closure (VAC) pending formal margin analysis, with coverage performed in the setting of final negative margins.

METHODS

This retrospective analysis included all patients managed at a tertiary referral cancer center with VAC temporization after soft tissue sarcoma or benign aggressive tumor excision from 1 January 2000 to 1 January 2019 and at least 2 years of oncologic follow-up evaluation. The primary outcome was local recurrence. The secondary outcomes were distant recurrence, unplanned return to the operating room for wound/infectious indications, thromboembolic events, and tumor-related deaths.

RESULTS

For 62 patients, VAC temporization was performed. The mean age of the patients was 62.2 ± 22.3 years (median 66.5 years; 95% confidence interval [CI] 61.7-72.5 years), and the mean age-adjusted Charlson Comorbidity Index was 5.3 ± 1.9. The most common tumor histology was myxofibrosarcoma (51.6%, 32/62). The mean volume was 124.8 ± 324.1 cm³, and 35.5% (22/62) of the cases were subfascial. Local recurrences occurred for 8.1% (5/62) of the patients. Three of these five patients had planned positive margins, and 17.7% (11/62) of the patients had an unplanned return to the operating room. No demographic or tumor factors were associated with unplanned surgery.

CONCLUSIONS

The findings showed that VAC-temporized management of microinvasive sarcoma and benign aggressive pathologies yields favorable local recurrence and unplanned operating room rates suggestive of oncologic and technical safety. These findings will need validation in a future randomized controlled trial.

Pseudoprogression of Malignant Peripheral Nerve Sheath Tumor in Patient with Neurofibromatosis Type 1, a Case Report

Pseudoprogression, defined as the radiographic false appearance of disease progression, is not frequently observed in patients with malignant peripheral nerve sheath tumor (MPNST). We report on a case of a patient with neurofibromatosis type 1 (NF1) MPNST pseudoprogression that presented as suspected local recurrence 9.5 years after last treatment. The patient underwent surgical resection following growth of a mass on sequential MRI imaging; surgical pathology, however, showed skeletal muscle with atrophy, fibroadipose tissue, and fat necrosis, without any evidence of tumor. As MPNST survival rates increase, physicians should consider pseudoprogression as a potential presentation after prior treatment.

Adjunct diagnostic strategies in improving diagnostic yields in image-guided biopsies of musculoskeletal neoplasms-A cost-effectiveness analysis

BACKGROUND

Routine use of adjunct intraprocedural fresh frozen biopsy (FFP) or point-of-care (POC) cytology at the time of image-guided biopsy can improve diagnostic tissue yields for musculoskeletal neoplasms, but these are associated with increased costs.

OBJECTIVE

This study aimed to ascertain the most cost-effective adjunctive test for image-guided biopsies of musculoskeletal neoplasms.

METHODS

This expected value cost-effectiveness microsimulation compared the payoffs of cost (2020 United States dollars) and effectiveness (quality-adjusted life, in days) on each of the competing strategies. A literature review and institutional data were used to ascertain probabilities, diagnostic yields, utility values, and direct medical costs associated with each strategy. Payer and societal perspectives are presented. One- and two-way sensitivity analyses evaluated model uncertainties.

RESULTS

The total cost and effectiveness for each of the strategies were $1248.98, $1414.09, $1980.53, and 80.31, 79.74, 79.69 days for the use of FFP, permanent pathology only, and POC cytology, respectively. The use of FFP dominated the competing strategies. Sensitivity analyses revealed FFP as the most cost-effective across all clinically plausible values.

CONCLUSIONS

Adjunct FFP is most cost-effective in improving the diagnostic yield of image-guided biopsies for musculoskeletal neoplasms. These findings are robust to sensitivity analyses using clinically plausible probabilities.

Clinical Utility of Anchored Multiplex Solid Fusion Assay for Diagnosis of Bone and Soft Tissue Tumors

Sarcoma diagnosis has become increasingly complex, requiring a combination of morphology, immunohistochemistry, and molecular studies to derive specific diagnoses. We evaluated the role of anchored multiplex polymerase chain reaction-based gene fusion assay in sarcoma diagnostics. Between 2015 and 2018, bone and soft tissue sarcomas with fusion assay results were compared with the histologic diagnosis. Of 143 sarcomas tested for fusions, 43 (30%) had a detectable fusion. In review, they could be classified into 2 main categories: (1) 31 tumors with concordant morphologic and fusion data; and (2) 12 tumors where the fusion panel identified an unexpected rearrangement that played a significant role in classification. The overall concordance of the fusion assay results with morphology/immunohistochemistry or alternate confirmatory molecular studies was 83%. Collectively, anchored multiplex polymerase chain reaction-based solid fusion assay represents a robust means of detecting targeted fusions with known and novel partners. The predictive value of the panel is highest in tumors that show a monomorphic cell population, round cell tumors, as well as tumors rich in inflammatory cells. However, with an increased ability to discover fusions of uncertain significance, it remains essential to emphasize that the diagnosis of bone and soft tissue neoplasms requires the integration of morphology and immunohistochemical profile with these molecular methods, for accurate diagnosis and optimal clinical management of sarcomas.

Temporizing Wound VAC Dressing Until Final Negative Margins are Achieved Reduces Myxofibrosarcoma Local Recurrence

BACKGROUND

The microinvasive nature of suprafascial myxofibrosarcoma reduces the accuracy of intraoperative margin assessment, and tumor bed resections after soft-tissue reconstruction are unreliable. In 2017, we began temporizing the excised tumor bed with a wound VAC, delaying soft-tissue coverage until final negative margins were achieved. We compare the oncologic/surgical outcomes of suprafascial myxofibrosarcomas managed with VAC temporization (VT) with single-stage excision/reconstruction (SS).

METHODS

We retrospectively studied suprafascial myxofibrosarcomas managed from January 1, 2000 to January 1, 2019 for patients who received neoadjuvant or adjuvant radiation and had at least 2 years of oncologic follow-up at a tertiary referral cancer center. Our primary outcome was local recurrence. Comparisons were performed by using Fisher's exact test or Student's t test. A p value < 0.05 was considered significant.

RESULTS

Fifty-three patients (18 VAC temporized, 35 single stage) were included. While VT patients were older (74.9 ± 10.2 vs. 63.9 ± 13.6, p = 0.003), treatment groups did not significantly differ with respect to comorbidity, tumor volume, stage and grade. VT patients had significantly fewer local recurrences (5.6% vs. 28.6% after SS, p = 0.048) and R1 resections that required an unplanned readmission for tumor bed reexcision (0% vs. 37.1% after SS, p = 0.002). VT required more total surgeries (2.8 ± 0.9 vs. 1.8 ± 0.9 for SS, p = 0.0002). Postoperative infectious and wound complications were equivalent.

CONCLUSIONS

Our VAC temporization strategy had a significantly lower LR than SS treatment. While high quality multi-institutional validation is required, VT may represent a paradigm shift in the management of myxofibrosarcoma.

Characteristics and oncologic outcomes of patients with Ewing sarcoma of the scapula

BACKGROUND AND OBJECTIVES

Ewing sarcoma is the second most common bone sarcoma of childhood. Ewing sarcomas of the scapula are rare, with little known about their characteristics and outcomes. In this study, we describe the demographic characteristics, tumor characteristics, and oncologic outcomes of patients with Ewing sarcoma of the scapula.

METHODS

This is a retrospective case series of thirty-four patients treated at three urban hospitals between 1993 and 2014 for Ewing sarcomas affecting the scapula. Their demographic data, tumor characteristics, and oncologic outcomes are reported and contrasted with data on Ewing sarcoma described in the literature.

RESULTS

Patients in our case series were 59% male. The average age at diagnosis was 16 years. 44% of patients had metastatic disease at presentation. 26% of patients had a tumor size >8 cm in largest dimension at diagnosis. 9 patients in our series had the t (11; 22) translocation present. Patients had a survival rate of 68% at five years. No patients had local recurrence of disease. Compared with findings reported in the literature concerning Ewing sarcoma affecting other locations, patients with Ewing sarcoma of the scapula were slightly older at time of diagnosis, had a lower percentage of tumors with size > 8 cm in largest dimension at presentation, and more commonly had metastatic disease at presentation. Patients in our cohort had a 5-year survival rate of 68%, which is higher than the rate of approximately 55% as reported in the general literature.

CONCLUSIONS

In this study, we describe a retrospective case series of thirty-four patients with Ewing sarcomas of the scapula. This is the largest case series to date of Ewing sarcoma affecting this location to our knowledge. These results will contribute to the understanding of the clinical profile and oncologic behavior of Ewing sarcomas affecting the scapula.

Surface osteosarcoma: Predictors of outcomes

BACKGROUND AND OBJECTIVES

The subtypes of surface osteosarcomas include well-differentiated, low-grade parosteal osteosarcoma (POS), intermediate-grade periosteal osteosarcoma (PerOS), high-grade surface osteosarcoma (HGSO), and high-grade, dedifferentiated POS (dPOS). We aimed to determine disease progression, defined as local recurrence and metastatic disease, and overall (OS) and disease-specific survival (DSS). We identify outcome predictive factors and report functional results.

METHODS

This retrospective study evaluated patients with primary surface osteosarcoma at our hospital from 1992 to 2019. Fifty-one patients had a median follow-up of 6.1 years (range: 0.1-25.2). Histologic subtypes included 32 POS, 11 PerOS, 4 HGSO, and 3 dPOS. Bone and soft tissue margins were classified using the American Joint Committee on Cancer residual tumor classification (Rx = Not evaluable; R0 = negative margin; R1 = microscopic positive margin; and R2 = macroscopic positive margin) and the modified R classification (mRx = not evaluable; mR0 = negative margin >1 mm; mR1 = negative margin ≤1 mm; mR1-dir: Positive microscopic margin locally; mR2a: Positive macroscopic margin locally; mR2b: positive macroscopic margin distally; and mR2C: positive macroscopic margin locally and distally). Forty-one patients had functional outcomes.

RESULTS

Three POS patients developed recurrence: two had R0 margins and one an intralesional resection. Five patients developed lung metastases (POS: 3, dPOS: 2). Four patients died. The only significant disease progression predictor was age. OS at 10 years was 97%. 48 patients had negative bone margins (R0 or mR0 and mR1) and 47 patients had negative soft-tissue margins (R0 or mR0 and mR1). The average MSTS score was 88.43 (range: 34.29-100).

CONCLUSIONS

We advocate surgery for POS and believe R0 (mR0 and mR1 resections) or planned R1 (mR1-dir) to preserve function are acceptable. We favor chemotherapy and surgery for PerOS, though a chemotherapeutic response is highly variable. High-grade tumors are the most infrequent subtype, but HGSO and dPOS seem to portend a poorer prognosis. Good function can be obtained.

Low-dose preoperative radiation, resection, and reduced-field postoperative radiation for soft tissue sarcomas

BACKGROUND AND OBJECTIVES

Radiotherapy (RT) enables conservative surgery for soft tissue sarcoma (STS). RT can be delivered either pre-operatively (PreRT) or postoperatively (PORT), yet in some patients, neither approach is fully satisfactory (e.g., urgent surgery or wound healing risk prevents PreRT, yet PORT alone cannot cover the entire surgical field). We hypothesized that, in such situations, low-dose PreRT (LD-PreRT) would decrease the risk of intraoperative tumor seeding and thus permit PORT to a reduced volume (covering the high-risk tumor bed but not all surgically manipulated tissues).

METHODS

We identified a single-institution retrospective cohort of 78 patients treated with LD-PreRT (10-30 Gy), resection, and PORT between 1980 and 2018.

RESULTS

At a median follow-up of 8.2 years, 8-year overall survival (OS) was 65.9%, disease-free survival (DFS) 50.5%, and local control (LC) 76.7%; in 45 patients with extremity/superficial trunk (E/ST) STS, 8-year LC was 80.9%. Both before and after propensity score adjustment, there were no differences in OS, DFS, or LC between this cohort and a separate cohort of 394 STS (221 E/ST-STS) patients treated with surgery and PORT alone.

CONCLUSIONS

In patients for whom neither PreRT nor PORT alone is optimal, LD-PreRT may prevent intraoperative tumor seeding and enable PORT to a reduced volume while preserving oncologic outcomes.

Do Cohabitants Reliably Complete Questionnaires for Patients in a Terminal Cancer Stage when Assessing Quality of Life, Pain, Depression, and Anxiety?

BACKGROUND

Patients with bone metastases often are unable to complete quality of life (QoL) questionnaires, and cohabitants (such as spouses, domestic partners, offspring older than 18 years, or other people who live with the patient) could be a reliable alternative. However, the extent of reliability in this complicated patient population remains undefined, and the influence of the cohabitant's condition on their assessment of the patient's QoL is unknown.

QUESTIONS/PURPOSES

(1) Do QoL scores, measured by the 5-level EuroQol-5D (EQ-5D-5L) version and the Patient-reported Outcomes Measurement Information System (PROMIS) version 1.0 in three domains (anxiety, pain interference, and depression), reported by patients differ markedly from scores as assessed by their cohabitants? (2) Do cohabitants' PROMIS-Depression scores correlate with differences in measured QoL results?

METHODS

This cross-sectional study included patients and cohabitants older than 18 years of age. Patients included those with presence of histologically confirmed bone metastases (including lymphoma and multiple myeloma), and cohabitants must have been present at the clinic visit. Patients were eligible for inclusion in the study regardless of comorbidities, prognosis, prior surgery, or current treatment. Between June 1, 2016 and March 1, 2017 and between October 1, 2017 and February 26, 2018, all 96 eligible patients were approached, of whom 49% (47) met the selection criteria and were willing to participate. The included 47 patient-cohabitant pairs independently completed the EQ-5D-5L and the eight-item PROMIS for three domains (anxiety, pain, and depression) with respect to the patients' symptoms. The cohabitants also completed the four-item PROMIS-Depression survey with respect to their own symptoms.

RESULTS

There were no clinically important differences between the scores of patients and their cohabitants for all questionnaires, and the agreement between patient and cohabitant scores was moderate to strong (Spearman correlation coefficients ranging from 0.52 to 0.72 on the four questionnaires; all p values < 0.05). However, despite the good agreement in QoL scores, an increased cohabitant's depression score was correlated with an overestimation of the patient's symptom burden for the anxiety and depression domains (weak Spearman correlation coefficient of 0.33 [95% confidence interval 0.08 to 0.58]; p = 0.01 and moderate Spearman correlation coefficient of 0.52 [95% CI 0.29 to 0.74]; p < 0.01, respectively).

CONCLUSION

The present findings support that cohabitants might be reliable raters of the QoL of patients with bone metastases. However, if a patient's cohabitant has depression, the cohabitant may overestimate a patient's symptoms in emotional domains such as anxiety and depression, warranting further research that includes cohabitants with and without depression to elucidate the effect of depression on the level of agreement. For now, clinicians may want to reconsider using the cohabitant's judgement if depression is suspected.

CLINICAL RELEVANCE

These findings suggest that a cohabitant's impressions of a patient's quality of life are, in most instances, accurate; this is potentially helpful in situations where the patient cannot weigh in. Future studies should employ longitudinal designs to see how or whether our findings change over time and with disease progression, and how specific interventions-like different chemotherapeutic regimens or surgery-may factor in.

Identification of EWSR1-NFATC2 fusion in simple bone cysts

AIMS

Simple bone cysts are benign intramedullary tumours primarily involving the long bones in skeletally immature individuals. Several mechanisms have been proposed for their pathogenesis. Although the diagnosis is typically straightforward, the interpretation can be problematic, because of superimposed fracture causing them to resemble aneurysmal bone cysts and other tumours. EWSR1-NFATC2 or FUS-NFATC2 fusions, which are characteristic of a subset of aggressive round cell sarcomas, have been recently detected in simple bone cysts. The aim of this study was to examine the clinicopathological and molecular features in a series of simple bone cysts.

METHODS AND RESULTS

Using RNA-based next-generation sequencing and/or fluorescence in-situ hybridisation, we investigated the presence of EWSR1 or FUS rearrangements in nine simple bone cysts. The patients were five females and four males, aged 3-23 years (median, 14 years); the tumours ranged from 19 mm to 160 mm (median, 46 mm) in size, and involved the femur (n = 3), humerus (n = 2), fibula (n = 2), tibia (n = 1), and iliac wing (n =1). We identified three cases with EWSR1-NFATC2 fusion (showing identical breakpoints to those in EWSR1-NFATC2 sarcomas) and one additional case with FUS rearrangement. Unlike in EWSR1-NFATC2 sarcomas, immunohistochemical expression of NKX3.1 and NKX2.2 was absent in two simple bone cysts tested.

CONCLUSIONS

More than 40% of simple bone cysts harbour genetic alterations confirming that they are neoplastic, investigation of EWSR1 and/or FUS rearrangement may help to distinguish simple bone cysts from mimics, and NFATC2 rearrangement is not pathognomonic of malignancy.

Orthopaedic Disaster Course: Preparing for the Worst/Best Moment in the Operating Room

Orthopaedic surgeons perform a variety of procedures where life-threatening or limb-threatening clinical scenarios or complications are relatively rare. Because these devastating complications and disaster presentations are infrequent, the occurrence can lead to concerns regarding training and preparedness. This chapter will provide a general knowledge base of common intraoperative disasters as well as life-threatening and/or limb-threatening conditions related to the upper extremity, pelvis, and lower extremity. Fundamental clinical and surgical management strategies are explored with respect to these conditions to provide a level of preparedness to help any orthopaedic surgeon control a potentially devastating complication or emergency.

Diagnoses, treatment, and oncologic outcomes in patients with calcaneal malignances: Case series, systematic literature review, and pooled cohort analysis

BACKGROUND AND OBJECTIVES

Malignant tumors of the calcaneus are rare but pose a treatment challenge.

AIMS

(1) describe the demographics of calcaneal malignancies in a large cohort; (2) describe survival after amputation versus limb-salvage surgery for high-grade tumors.

METHODS

Study group: a "pooled" cohort of patients with primary calcaneal malignancies treated at two cancer centers (1984-2015) and systematic literature review. Kaplan-Meier analyses described survival across treatment and diagnostic groups; proportional hazards modeling assessed mortality after amputation versus limb salvage.

RESULTS

A total of 131 patients (11 treated at our centers and 120 patients from 53 published studies) with a median 36-month follow-up were included. Diagnoses included Ewing sarcoma (41%), osteosarcoma (30%), and chondrosarcoma (17%); 5-year survival rates were 43%, 73% (70%, high grade only), and 84% (60%, high grade only), respectively. Treatment involved amputation in 52%, limb salvage in 27%, and no surgery in 21%. There was no difference in mortality following limb salvage surgery (vs. amputation) for high-grade tumors (HR 0.38; 95% CI 0.14-1.05), after adjusting for Ewing sarcoma diagnosis (HR 5.15; 95% CI 1.55-17.14), metastatic disease at diagnosis (HR 3.88; 95% CI 1.29-11.64), and age (per-year HR 1.04; 95% CI 1.02-1.07).

CONCLUSIONS

Limb salvage is oncologically-feasible for calcaneal malignancies.

Serum alkaline phosphatase is a prognostic marker in bone metastatic disease of the extremity

Purpose

The purpose of this study was to determine the prognostic value of serum alkaline phosphatase for treatment decision making in metastatic bone disease.

Methods

1090 patients who underwent surgery for extremity metastatic disease were retrospectively identified at two tertiary care centers. The association between alkaline phosphatase and mortality was assessed by bivariate and multivariate analyses.

Results

Three-month and one-year mortality rates were 305 (29%) and 639 (62%), respectively. Alkaline phosphatase was associated with mortality at both three months and one year.

Conclusion

Serum alkaline phosphatase may be a useful marker in prognostic algorithms for patients with extremity metastatic disease.

Physical function and pain intensity in patients with metastatic bone disease

BACKGROUND

Patient reported outcome data in bone metastatic disease are scarce and it would be useful to have normative data and understand what patients are at risk for poor function and more pain.

OBJECTIVES

We aimed to assess what factors are independently associated with physical function and pain intensity in patients with bone metastasis.

METHODS

We included data from 211 patients with bone metastasis who completed a survey (2014-2016) including the PROMIS Physical Function Cancer and PROMIS Pain Intensity questionnaires.

RESULTS

Prostate (P < .001) and thyroid carcinoma (P = .007) were associated with better function and having other disabling conditions (P = 0.035) was associated with worse function. Prostate carcinoma (P = .001) and lymphoma (P = .007) were associated with less pain. There was a moderate correlation between pain and function (P < .001). Function was substantially worse as compared to a US reference population of patients with cancer (P < .001), whereas pain was slightly less compared to the US general population average (P < .001).

CONCLUSIONS

Patients with bone metastasis have a poor physical function. Physical function and pain intensity depend on tumor histology, but also on potentially modifiable factors such as other disabling conditions.

LEVEL OF EVIDENCE

Level III, prognostic study.

Radiation-induced and neurofibromatosis-associated malignant peripheral nerve sheath tumors (MPNST) have worse outcomes than sporadic MPNST

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNST) may be sporadic or associated with neurofibromatosis or prior radiation. MPNST may behave aggressively with a high rate of local recurrence and distant metastasis.

METHODS

In an IRB approved protocol, we reviewed the clinical characteristics, treatment, and outcomes of 280 patients treated for MPNST at Massachusetts General Hospital (MGH) between 1960 and 2016.

RESULTS

There were 138 men and 142 women with a median age of 41 (range: 3-95) years. Tumors were classified as neurofibromatosis-associated (nfMPNST, n = 77), radiation-induced (rMPNST, n = 21), or sporadic (sMPNST, n = 182) MPNST. The median time to development of rMPNST from prior radiation was 15 years. With a median follow-up of 43.1 months, the median overall survival (OS) was 65.3 months. Older age, nfMPNST, rMPNST, increased tumor size, lymph node involvement, metastatic disease, intermediate to high grade, radiotherapy alone, and R2 resection were related to worse OS, whereas surgery with radiotherapy was associated with improved OS. Among the 251 patients without metastasis, nfMPNST, rMPNST, and increased tumor size were correlated with worse metastasis-free survival; nfMPNST, radiotherapy alone, and R1/R2 resection were associated with local recurrence, whereas surgery with adjuvant radiotherapy was related to improved local control in patients with R1/R2 resection.

CONCLUSIONS

Both radiation-induced and neurofibromatosis-associated MPNSTs have poorer prognosis than sporadic MPNSTs. Complete resection of the tumor is a significant prognostic factor for MPNST. The addition of radiotherapy after surgery should be considered especially when the surgical margins are positive.

Genomewide Association Study of Fracture Nonunion Using Electronic Health Records

Nonunion is a clinically significant complication of fracture associated with worse outcomes, including increased pain, disability, and higher healthcare costs. The risk for nonunion is likely to be complex and multifactorial, and as such, the biology underlying such risk remains poorly understood. Genetic studies represent one approach to identify implicated biology for further investigation, but to date the lack of large cohorts for study has limited such efforts. We utilized the electronic health records of two large academic medical centers in Boston to identify individuals with fracture nonunion and control individuals with fracture but no evidence of nonunion. We conducted a genomewide association study among 1760 individuals of Northern European ancestry with upper or lower extremity fracture, including 131 with nonunion, to examine whether common variants were associated with nonunion in this cohort. In all, one locus in the Calcyon (CALY) gene exceeded a genomewide threshold for statistical significance (p = 1.95e-8), with eight additional loci associated with p < 5e-7. Previously reported candidate genes were not supported by this analysis. Electronic health records should facilitate identification of common genetic variations associated with adverse orthopedic outcomes. The loci we identified in this small cohort require replication and further study to characterize mechanism of action, but represent a starting point for the investigation of genetic liability for this costly outcome.

Aneurysmal bone cyst of the clavicle: a series of 13 cases

BACKGROUND

Aneurysmal bone cyst (ABC) is a benign but locally aggressive bone tumor occurring most commonly in the first 2 decades of life. The clavicle is a rare location for tumors, and ABCs of the clavicle have been sparsely described in the literature. We present the largest known series of ABCs of the clavicle to describe this rare condition.

METHODS

Patients were identified retrospectively from an orthopedic oncology database to obtain demographic, diagnostic, and treatment information. A literature search was performed to identify all English language reports of ABC of the clavicle.

RESULTS

We identified 13 patients with ABC of the clavicle, 77% of which were in the acromial end. Most patients (77%) presented with pain or swelling or both. The initial treatment in 11 patients was by curettage, with or without allograft bone packing, and 1 underwent resection/reconstruction of the lateral clavicle. Seven patients (58%) had 1 or more recurrences at an average of 6 months, for which 2 were treated with partial resection of the clavicle.

CONCLUSIONS

ABC of the clavicle is a rare condition that we found to occur most frequently in the acromial end of the bone. Most patients were initially treated with curettage and showed a higher rate of recurrence than in other locations. The unique anatomy of the clavicle makes resection a feasible and very functional option, especially if the coracoclavicular ligaments can be preserved. However, the potential resulting deformity may cause patients to opt for a less aggressive and, consequently, less effective treatment method.

Allograft reconstruction of the humerus: Complications and revision surgery

BACKGROUND AND OBJECTIVES

Allograft reconstruction of the humerus after resection is preferred by many because of bone stock restoration and biologic attachment of ligaments and muscles to the allograft, theoretically obtaining superior stability and functionality. Our aim was to assess the prevalence of complications and the incidence and etiology for revision surgery in humeral allograft reconstructions.

METHODS

We included patients 18 years and older who underwent wide resection and allograft reconstruction of the humerus for primary and metastatic lesions at our institution between 1990 and 2013. Our primary outcome measures were complications and revision surgery. We used competing risk regression to assess allograft survival.

RESULTS

Of the 84 patients we included, 47 patients (51%) underwent allograft reconstructions of the proximal humerus, 30 (36%) intercalary, and seven (8%) of the distal humerus. Fifty-one patients (61%) had at least one complication after surgery. Eighteen patients (21%) underwent revision surgery. The 5-year allograft survival was 71%.

CONCLUSION

Although allograft reconstructions of the humerus are a valuable option in the orthopedic oncologist's armamentarium, surgeons should mind the accompanying complication rates. Allograft fractures seem to be the main issue for proximal and distal allografts, often leading to revision surgery. Intercalary allografts are mostly troubled by nonunions.

Can Machine-learning Techniques Be Used for 5-year Survival Prediction of Patients With Chondrosarcoma?

BACKGROUND

Several studies have identified prognostic factors for patients with chondrosarcoma, but there are few studies investigating the accuracy of computationally intensive methods such as machine learning. Machine learning is a type of artificial intelligence that enables computers to learn from data. Studies using machine learning are potentially appealing, because of its possibility to explore complex patterns in data and to improve its models over time.

QUESTIONS/PURPOSES

The purposes of this study were (1) to develop machine-learning algorithms for the prediction of 5-year survival in patients with chondrosarcoma; and (2) to deploy the best algorithm as an accessible web-based app for clinical use.

METHODS

All patients with a microscopically confirmed diagnosis of conventional or dedifferentiated chondrosarcoma were extracted from the Surveillance, Epidemiology, and End Results (SEER) Registry from 2000 to 2010. SEER covers approximately 30% of the US population and consists of demographic, tumor characteristic, treatment, and outcome data. In total, 1554 patients met the inclusion criteria. Mean age at diagnosis was 52 years (SD 17), ranging from 7 to 102 years; 813 of the 1554 patients were men (55%); and mean tumor size was 8 cm (SD 6), ranging from 0.1 cm to 50 cm. Exact size was missing in 340 of 1544 patients (22%), grade in 88 of 1544 (6%), tumor extension in 41 of 1544 (3%), and race in 16 of 1544 (1%). Data for 1-, 3-, 5-, and 10-year overall survival were available for 1533 (99%), 1512 (98%), 1487 (96%), and 977 (63%) patients, respectively. One-year survival was 92%, 3-year survival was 82%, 5-year survival was 76%, and 10-year survival was 54%. Missing data were imputed using the nonparametric missForest method. Boosted decision tree, support vector machine, Bayes point machine, and neural network models were developed for 5-year survival. These models were chosen as a result of their capability of predicting two outcomes based on prior work on machine-learning models for binary classification. The models were assessed by discrimination, calibration, and overall performance. The c-statistic is a measure of discrimination. It ranges from 0.5 to 1.0 with 1.0 being perfect discrimination and 0.5 that the model is no better than chance at making a prediction. The Brier score measures the squared difference between the predicted probability and the actual outcome. A Brier score of 0 indicates perfect prediction, whereas a Brier score of 1 indicates the poorest prediction. The Brier scores of the models are compared with the null model, which is calculated by assigning each patient a probability equal to the prevalence of the outcome.

RESULTS

Four models for 5-year survival were developed with c-statistics ranging from 0.846 to 0.868 and Brier scores ranging from 0.117 to 0.135 with a null model Brier score of 0.182. The Bayes point machine was incorporated into a freely available web-based application. This application can be accessed through https://sorg-apps.shinyapps.io/chondrosarcoma/.

CONCLUSIONS

Although caution is warranted, because the prediction model has not been validated yet, healthcare providers could use the online prediction tool in daily practice when survival prediction of patients with chondrosarcoma is desired. Future studies should seek to validate the developed prediction model.

LEVEL OF EVIDENCE

Level III, prognostic study.

Exploiting MCL1 Dependency with Combination MEK + MCL1 Inhibitors Leads to Induction of Apoptosis and Tumor Regression in KRAS-Mutant Non-Small Cell Lung Cancer

BH3 mimetic drugs, which inhibit prosurvival BCL2 family proteins, have limited single-agent activity in solid tumor models. The potential of BH3 mimetics for these cancers may depend on their ability to potentiate the apoptotic response to chemotherapy and targeted therapies. Using a novel class of potent and selective MCL1 inhibitors, we demonstrate that concurrent MEK + MCL1 inhibition induces apoptosis and tumor regression in KRAS-mutant non-small cell lung cancer (NSCLC) models, which respond poorly to MEK inhibition alone. Susceptibility to BH3 mimetics that target either MCL1 or BCL-xL was determined by the differential binding of proapoptotic BCL2 proteins to MCL1 or BCL-xL, respectively. The efficacy of dual MEK + MCL1 blockade was augmented by prior transient exposure to BCL-xL inhibitors, which promotes the binding of proapoptotic BCL2 proteins to MCL1. This suggests a novel strategy for integrating BH3 mimetics that target different BCL2 family proteins for KRAS-mutant NSCLC. SIGNIFICANCE: Defining the molecular basis for MCL1 versus BCL-xL dependency will be essential for effective prioritization of BH3 mimetic combination therapies in the clinic. We discover a novel strategy for integrating BCL-xL and MCL1 inhibitors to drive and subsequently exploit apoptotic dependencies of KRAS-mutant NSCLCs treated with MEK inhibitors.See related commentary by Leber et al., p. 1511.This article is highlighted in the In This Issue feature, p. 1494.

Primary arthroplasty in healed osteoarticular allograft in patients with history of primary femoral bone tumors

BACKGROUND

Roughly 25-35% of patients who are treated with osteoarticular allograft for primary bone sarcomas or aggressive benign bone tumors require surgery in the long-term due to degenerative changes of the articular surface of the allograft. There are three established methods of reconstruction for this complication; a total hip arthroplasty (THA) or total knee arthroplasty (TKA) in the retained osteoarticular allograft, a proximal or distal endoprosthesis after removal of the allograft, and an allograft-prosthesis composite (APC). The aims of this study are 1) to determine the rate of complication and failure of THA/TKA in healed femoral allograft; 2) to compare the methods of revision for allograft degeneration; and 3) to compare the use of arthroplasty in healed allograft to that of arthroplasty in native bone.

METHODS

We included all patients with primary bone sarcomas and locally aggressive primary benign bone tumors treated between 1984 and 2014 with an osteoarticular allograft followed by any subsequent arthroplasty technique as described above. Complications and reasons for failure are described following the classification of Henderson et al. Failure was defined as any complication leading to removal of the initial treatment construct. Failure rates of these groups were compared to primary arthroplasty in a live host bone (Control Group).

RESULTS

Complications happened in 25 (61.0%) of the patients with a THA/TKA in the retained allograft, of these, 24 (58.5%) experienced failure, the most common being structural failure/type III (14, 58.3%). Thirteen patients (81.3%) with an endoprosthesis after removal of the allograft experienced complications, all of whom failed. The most common failure modes were aseptic loosening/type II (4, 30.8%) and infection/type IV (5, 38.5%). Complications in patients with an APC were experienced by 12 (85.7%) patients, 11 (78.6%) of whom failed. The most common failure mode was infection/type IV (4, 36.4%). Significantly (p < 0.001) fewer failures were observed in the control group compared to patients with an arthroplasty in a healed allograft.

CONCLUSIONS

We found no significant difference in the outcome of treating patients with allograft and subsequent degenerative bone disease with a THA/TKA in a retained allograft, an endoprosthesis after removal of the allograft, or a primary APC, although infection is a significantly greater cause of failure in the latter two. Primary arthroplasty in healed allografts is a less extensive surgery than removing the allograft and shows comparable complication and failure rates.

LEVEL OF EVIDENCE

Level III, Therapeutic Study.

Most efficient questionnaires to measure quality of life, physical function, and pain in patients with metastatic spine disease: a cross-sectional prospective survey study

BACKGROUND CONTEXT

Assessing quality of life, functional outcome, and pain has become important in assessing the effectiveness of treatment for metastatic spine disease. Many questionnaires are able to measure these outcomes; few are validated in patients with metastatic spine disease. As a result, there is no consensus on the ideal questionnaire to use in these patients.

PURPOSE

Our study aim was to assess whether certain questionnaires measuring quality of life, functional outcome, and pain (1) correlated with each other, (2) measured the construct they claim to measure, (3) had good coverage-floor and ceiling effects, (4) were reliable, and (5) whether there were differences in completion time between them.

DESIGN

This is a prospective cross-sectional survey study from three outpatient clinics (two orthopedic oncology clinics and one neurosurgery clinic) from two affiliated tertiary hospital care centers.

PATIENT SAMPLE

We included 100 consecutive patients with metastatic spine disease between July 2014 and February 2016. We excluded non-English-speaking patients.

OUTCOME MEASURES

The following questionnaires were given in random order: Oswestry Disability Index (ODI) or Neck Disability Index (NDI), Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function, PROMIS Pain Intensity, EuroQol-5 Dimensions (EQ-5D), and the Spine Oncology Study Group Outcome Questionnaire (SOSG-OQ).

METHODS

We used exploratory factor analysis-correlating questionnaires with an underlying mathematically derived trait-to assess if questionnaires measured the same concept. Coverage was assessed by floor and ceiling effects, and reliability was assessed by standard error of measurement as a function of ability. Differences in completion times were tested using the Friedman test.

RESULTS

Questionnaires measured the construct they were developed for, as demonstrated with high correlations (>0.7) with the underlying trait. A floor effect was present in the PROMIS Pain Intensity (7.0%), ODI or NDI (4.0%), and the PROMIS Physical Function (1.0%) questionnaires. A ceiling effect was present in the EQ-5D questionnaire (6.0%). The SOSG-OQ had no floor or ceiling effect. The PROMIS Physical Function and PROMIS Pain Intensity proved to be the most reliable, whereas the EQ-5D was the least reliable. Completion time differed among questionnaires (p<.001) and was shortest for the PROMIS Pain Intensity (median 24 seconds) and PROMIS Physical Function (median 42 seconds).

CONCLUSIONS

In patients with metastatic spine disease, we recommend the SOSG-OQ for measuring quality of life, the PROMIS Physical Function for measuring physical function, and the PROMIS Pain Intensity for measuring pain.

Functional and oncological outcome after surgical resection of the scapula and clavicle for primary chondrosarcoma

PURPOSE

The scapula is a relatively common site for chondrosarcoma to develop in contrary to the clavicle, which is rarely affected by these tumors. The aim of this study is to determine the functional and oncological outcome for patients treated operatively for scapular or clavicular chondrosarcoma.

METHODS

In this single-center retrospective study, we included a sample of 20 patients that received the diagnosis of a primary chondrosarcoma of the scapula or clavicle. Of the surviving patients, the functional function was assessed using the DASH and the PROMIS Physical Function-Upper Extremity. Patients were longitudinally tracked for their oncological outcome.

RESULTS

All patients were followed for at least 2 years or until death. The mean age of the cohort was 47 years. Eighteen patients suffered from a chondrosarcoma of the scapula, and in 2 patients, the tumor was located in the clavicle. Metastasis, local recurrence and a higher tumor grade were all associated with a decreased overall survival. For the patients with a chondrosarcoma of the scapula, the average DASH score was 16 ± 16 and the mean PROMIS Physical Function-Upper Extremity score was 48 ± 10. Patients with both an intact rotator cuff and glenoid had a better physical function.

CONCLUSIONS

Upper extremity function after (partial) scapulectomy varied depending on whether the glenoid was spared and whether a functioning shoulder abductor remained. When the resection spared these structures, then excellent functional outcomes were reported. Oncologic outcomes depended upon the grade of the tumor and whether local recurrence and metastases occurred.

A comparison of questionnaires for assessing physical function in patients with lower extremity bone metastases

OBJECTIVES

To assess, (i) the degree to which the: PROMIS Physical Function Cancer, PROMIS Neuro-QoL Mobility, Toronto Extremity Salvage Score (TESS), Lower Extremity Function Score (LEFS), and Musculoskeletal Tumor Society score (MSTS), measure physical function; (ii) differences in coverage and reliability; and (iii) difference in completion time.

METHODS

One hundred of 115 (87%) patients with lower extremity metastases participated in this prospective study. We used exploratory factor analysis-correlating questionnaires with an underlying trait-to assess if questionnaires measure the same. Coverage was assessed by floor and ceiling effect and reliability by the standard error of measurement (SEM). Completion time was compared using the Friedman test.

RESULTS

All questionnaires measured the same concept; demonstrated by high correlations (>0.7). Floor effect was absent, while ceiling effect was present in all, but highest for the PROMIS Neuro-QoL Mobility (7%). The SEM was below the threshold-indicating reliability-over a wide range of ability levels for the PROMIS-Physical Function, TESS, and LEFS. Completion time differed between questionnaires (P < 0.001) and was shortest for the PROMIS questionnaires.

CONCLUSIONS

The PROMIS Physical Function is the most useful questionnaire. This is due to its reliability over a wide range of ability levels, validity, brevity, and good coverage. J. Surg. Oncol. 2016;114:691-696. © 2016 Wiley Periodicals, Inc.

Cemented Total Hip Arthroplasty With Retrograde Ischioacetabular Steinmann Pin Reconstruction for Periacetabular Metastatic Carcinoma

BACKGROUND

Surgical management of advanced periacetabular lesions is challenging because of extensive bone loss, particularly for Modified American Academy of Orthopaedic Surgeons Classification defects type IV (pelvic discontinuity with posterior column involvement). Multiple methods for rebuilding the acetabulum have been described; all involve passing Steinmann pins in a retrograde or an antegrade fashion from the anterior iliac wing or iliac crest around the acetabulum in an attempt to recreate the normal bony anatomy. However, these techniques fail to engage the ischium in its entirety. The ischial contribution to the posterior column is a critical element in a stable acetabular construct.

METHODS

After curettage of the acetabular lesion, Steinmann pins are passed through the ischial tuberosity and posterior column into the sciatic buttress in a retrograde manner. The number of pins depends on the size of the defect and involvement of the posterior column.

PATIENTS AND METHODS

Medical records of 11 patients with a Modified American Academy of Orthopaedic Surgeons Classification defect type IV treated with retrograde ischioacetabular Steinmann pin reconstruction at our institution between 2007 and 2012 were reviewed. European Quality of Life-5 dimensions and Lower Extremity Functional Scale questionnaires were used to assess patient functional outcomes.

RESULTS

The 6 patients (4 females and 2 males; age range, 56-81 years) surviving 12 months postoperatively reported improved mobility and good quality-of-life scores.

CONCLUSION

We described a new method for posterior acetabular column reconstruction that uses the ischial tuberosity and body as additional points of stabilization during the reconstruction of the posterior column.

Complications after surgery for metastatic humeral lesions

BACKGROUND

Knowledge of surgical outcome and its predictors helps inform patients and aids in surgical decision-making. We aimed to assess the outcome-reoperation and systemic complication rate-of surgery for humeral metastases, myeloma, or lymphoma. Our null hypothesis was that there are no factors associated with these outcomes.

METHODS

We included 295 consecutive patients in this retrospective study: 134 (45%) proximal, 131 (44%) diaphyseal, and 30 (10%) distal impending or pathologic fractures. Proximal lesions were treated by intramedullary nailing (43%, n = 57), prosthesis (34%, n = 46), plate-screw fixation (22%, n = 30), and a combination (n = 1). Diaphyseal lesions were treated by intramedullary nailing (69%, n = 91), plate-screw fixation (30%, n = 39), and a combination (n = 1). Distal lesions were treated by plate-screw fixation (97%, n = 29) and intramedullary nailing (3.3%, n = 1).

RESULTS

We found 25 (8.5%) reoperations, and 17 (5.8%) patients had 18 systemic complications: pneumonia (3.7%, n = 11), pulmonary embolism (1.3%, n = 4), sepsis (0.68%, n = 2), and fat embolism (0.34%, n = 1). No factors were independently associated with reoperation. Logistic regression analysis demonstrated that favorable cancer status (i.e., a higher modified Bauer score: odds ratio, 0.48; 95% confidence interval, 0.29-0.80; P = .005) was independently associated with a decreased systemic complication rate.

CONCLUSION

Poor cancer status was an independent predictor of postoperative systemic complications. This could help inform the patient and anticipate postoperative problems.