Percutaneous Cementation for Improvement of Pain and Function for Osteolytic Pelvic Metastasis: A Systematic Review

INTRODUCTION

Pelvic metastasis is a common presentation among patients presenting with skeletal metastasis. Image-guided percutaneous cementation of these lesions is becoming increasingly popular for the treatment of these lesions. The objective of this study was to conduct a systematic review that investigates clinical outcomes after percutaneous cementation for pelvic metastasis.

METHODS

A systematic review was registered with International Prospective Register of Systematic Reviews and performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using the PubMed, SCOPUS, and Ovid MEDLINE databases. All level I to IV clinical studies published in the English language investigating the clinical outcomes after percutaneous cementation for pelvic metastasis were included.

RESULTS

Fourteen studies with 579 patients (278 men, 301 women) and 631 metastatic pelvic lesions were included in the study. The mean follow-up range was 0.7 to 26.4 months. Percutaneous cementation alone was performed in 441 patients (76.2%). Supplemental ablative procedures were performed in 77 patients (13.3%), and supplemental internal fixation using cannulated screws was performed in 107 patients (18.5%). Twelve studies with 430 patients (74.2%) reported pain-related and/or functional outcome scores, of which all studies reported overall clinically notable improvement at short-term follow-up. All studies reported periprocedural complications. Local cement leakage was the most common complication (162/631 lesions, 25.7%) followed by transient local pain (25/579 patients, 4.3%). There were no reported cases of major complications. Seven patients (1.2%) underwent re-intervention for persistent symptoms.

CONCLUSIONS

Percutaneous cementation may be an effective method for treating pain and function related to pelvic metastasis. The most common complication was cement leakage surrounding the lesion. The rates of major complications were low, and most complications appeared minor and transient. Additional prospective studies are needed to further assess the efficacy of this procedure.

LEVEL OF EVIDENCE

IV, systematic review of level I to IV therapeutic studies.

A randomized, non-comparative phase 2 study of neoadjuvant immune-checkpoint blockade in retroperitoneal dedifferentiated liposarcoma and extremity/truncal undifferentiated pleomorphic sarcoma

Based on the demonstrated clinical activity of immune-checkpoint blockade (ICB) in advanced dedifferentiated liposarcoma (DDLPS) and undifferentiated pleomorphic sarcoma (UPS), we conducted a randomized, non-comparative phase 2 trial ( NCT03307616 ) of neoadjuvant nivolumab or nivolumab/ipilimumab in patients with resectable retroperitoneal DDLPS (n = 17) and extremity/truncal UPS (+ concurrent nivolumab/radiation therapy; n = 10). The primary end point of pathologic response (percent hyalinization) was a median of 8.8% in DDLPS and 89% in UPS. Secondary end points were the changes in immune infiltrate, radiographic response, 12- and 24-month relapse-free survival and overall survival. Lower densities of regulatory T cells before treatment were associated with a major pathologic response (hyalinization > 30%). Tumor infiltration by B cells was increased following neoadjuvant treatment and was associated with overall survival in DDLPS. B cell infiltration was associated with higher densities of regulatory T cells before treatment, which was lost upon ICB treatment. Our data demonstrate that neoadjuvant ICB is associated with complex immune changes within the tumor microenvironment in DDLPS and UPS and that neoadjuvant ICB with concurrent radiotherapy has significant efficacy in UPS.

Multimodality Imaging for 3D Printing and Surgical Rehearsal in Complex Spine Surgery

Surgery is the mainstay treatment of symptomatic spinal tumors. It aids in restoring functionality, managing pain and tumor growth, and improving overall quality of life. Over the past decade, advancements in medical imaging techniques combined with the use of three-dimensional (3D) printing technology have enabled improvements in the surgical management of spine tumors by significantly increasing the precision, accuracy, and safety of the surgical procedures. For complex spine surgical cases, the use of multimodality imaging is necessary to fully visualize the extent of disease, including both soft-tissue and bone involvement. Integrating the information provided by these examinations in a cohesive manner to facilitate surgical planning can be challenging, particularly when multiple surgical specialties work in concert. The digital 3-dimensional (3D) model or 3D rendering and the 3D printed model created from imaging examinations such as CT and MRI not only facilitate surgical planning but also allow the placement of virtual and physical surgical or osteotomy planes, further enhancing surgical planning and rehearsal. The authors provide practical information about the 3D printing workflow, from image acquisition to postprocessing of a 3D printed model, as well as optimal material selection and incorporation of quality management systems, to help surgeons utilize 3D printing for surgical planning. The authors also highlight the process of surgical rehearsal, how to prescribe digital osteotomy planes, and integration with intraoperative surgical navigation systems through a case-based discussion. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Customized 3-dimensional-printed Vertebral Implants for Spinal Reconstruction After Tumor Resection: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVE

To examine the outcomes of customized 3-dimensional (3D) printed implants for spinal reconstruction after tumor resection.

SUMMARY OF BACKGROUND DATA

Various techniques exist for spinal reconstruction after tumor resection. Currently, there is no consensus regarding the utility of customized 3D-printed implants for spinal reconstruction after tumor resection.

MATERIALS AND METHODS

A systematic review was registered with PROSPERO and performed according to "Preferred Reporting Items for Systematic Reviews and Meta-analyses" guidelines. All level I-V evidence studies reporting the use of 3D-printed implants for spinal reconstruction after tumor resection were included.

RESULTS

Eleven studies (65 patients; mean age, 40.9 ± 18.1 y) were included. Eleven patients (16.9%) underwent intralesional resections with positive margins and 54 patients (83.1%) underwent en bloc spondylectomy with negative margins. All patients underwent vertebral reconstruction with 3D-printed titanium implants. Tumor involvement was in the cervical spine in 21 patients (32.3%), thoracic spine in 29 patients (44.6%), thoracolumbar junction in 2 patients (3.1%), and lumbar spine in 13 patients (20.0%). Ten studies with 62 patients reported perioperative outcomes radiologic/oncologic status at final follow-up. At the mean final follow-up of 18.5 ± 9.8 months, 47 patients (75.8%) had no evidence of disease, 9 patients (14.5%) were alive with recurrence, and 6 patients (9.7%) had died of disease. One patient who underwent C3-C5 en bloc spondylectomy had an asymptomatic subsidence of 2.7 mm at the final follow-up. Twenty patients that underwent thoracic and/or lumbar reconstruction had a mean subsidence of 3.8 ± 4.7 mm at the final follow-up; however, only 1 patient had a symptomatic subsidence that required revision surgery. Eleven patients (17.7%) had one or more major complications.

CONCLUSION

There is some evidence to suggest that using customized 3D-printed titanium or titanium alloy implants is an effective technique for spinal reconstruction after tumor resection. There is a high incidence of asymptomatic subsidence and major complications that are similar to other methods of reconstruction.

LEVEL OF EVIDENCE

Level V, systematic review of level I-V studies.

The risk of neurological deterioration while using neoadjuvant denosumab on patients with giant cell tumor of the spine presenting with epidural disease: a meta-analysis of the literature

BACKGROUND CONTEXT

Giant cell tumor (GCT) of bone is most commonly a benign but locally aggressive primary bone tumor. Spinal GCTs account for 2.7% to 6.5% of all GCTs in bone. En bloc resection, which is the preferred treatment for GCT of the spine, may not always be feasible due to the location, extent of the tumor, and/or the patient's comorbidities. Neoadjuvant denosumab has recently been shown to be effective in downstaging GCT, decreasing the size and extent of GCTs. However, the risk of neurologic deterioration is of major concern for patients with epidural spinal cord compression due to spinal GCT. We experienced this concern when a patient presented to our institution with a mid-thoracic spinal GCT with progressive epidural disease. The patient was not a good surgical candidate due to severe cardiac disease and uncontrolled diabetes. In considering nonoperative management for this patient, we asked ourselves the following question: What is the risk that this patient will develop neurologic deterioration if we do not urgently operate and opt to treat him with denosumab instead?

PURPOSE

The purpose of this study was to assess the literature to (1) determine the risk of neurological deterioration in patients receiving neoadjuvant denosumab for the treatment of spinal GCT and (2) to evaluate the secondary outcomes including radiographic features, surgical/technical complexity, and histological features after treatment.

STUDY DESIGN/SETTING

Meta-analysis of the literature.

PATIENT SAMPLE

Surgical cases of spinal GCT that (1) presented with type III Campanacci lesions, (2) had epidural disease classified as Bilsky type 1B or above and (3) received neoadjuvant denosumab therapy.

OUTCOME MEASURES

The primary outcome measure of interest was neurologic status during denosumab treatment. Secondary outcome measures of interest included radiographic features, surgical/technical complexity, histological features, tumor recurrence, and metastasis.

METHODS

Using predetermined inclusion and exclusion criteria, PubMed and Embase electronic databases were searched in August 2022 for articles reporting spinal GCTs treated with neoadjuvant denosumab and surgery. Keywords used were "Spine" AND "Giant Cell Tumor" AND "Denosumab."

RESULTS

A total of 428 articles were identified and screened. A total of 22 patients from 12 studies were included for review. 17 patients were female (17/22, 77%), mean age was 32 years (18-62 years) and average follow-up was 21 months. Most GCTs occurred in the thoracic and thoracolumbar spine (11 patients, 50%), followed by 36% in the lumbar spine and 14% in the cervical spine. Almost half of the patients had neurological deficits at presentation (10/22 patients, 45%), and more than 60% had Bilsky 2 or 3 epidural spinal cord compression. None of the patients deteriorated neurologically, irrespective of their neurological status at presentation (p-value=.02, CI -2.58 to -0.18). There were no local recurrences reported. One patient was found to have lung nodules postoperatively. More than 90% of cases had decreased overall tumor size and increased bone formation. Surgical dissection was facilitated in more than 85% of those who had documented surgical procedures. Four patients (18%) underwent initial spinal stabilization followed by neoadjuvant denosumab and then surgical excision of the GCT. Regarding the histologic analyses, denosumab eradicated the giant cells in 95% of cases. However, residual Receptor Activator of Nuclear Factor Kappa B Ligand (RANKL)-positive stromal cells were noted, in 27% (6 cases).

CONCLUSIONS

Neoadjuvant denosumab was a safe and effective means of treating spinal GCTs prior to surgery. Neurologic status remained stable or improved in all cases included in our review, irrespective of the presenting neurologic status. The most appropriate dosage and duration of denosumab therapy is yet to be determined. We recommend future well-designed studies to further evaluate the use of neoadjuvant denosumab for patients with spinal GCT.

Advances in Virtual Cutting Guide and Stereotactic Navigation for Complex Tumor Resections of the Sacrum and Pelvis: Case Series with Short-Term Follow-Up

Primary malignancies of the sacrum and pelvis are aggressive in nature, and achieving negative margins is essential for preventing recurrence and improving survival after en bloc resections. However, these are particularly challenging interventions due to the complex anatomy and proximity to vital structures. Using virtual cutting guides to perform navigated osteotomies may be a reliable method for safely obtaining negative margins in complex tumor resections of the sacrum and pelvis. This study details the technique and presents short-term outcomes. Patients who underwent an en bloc tumor resection of the sacrum and/or pelvis using virtual cutting guides with a minimum follow-up of two years were retrospectively analyzed and included in this study. Preoperative computer-assisted design (CAD) was used to design osteotomies in each case. Segmentation, delineating the tumor from normal tissue, was performed by the senior author using preoperative CT scans and MRI. Working with a team of biomedical engineers, virtual surgical planning was performed to create osteotomy lines on the preoperative CT and overlaid onto the intraoperative CT. The pre-planned osteotomy lines were visualized as "virtual cutting guides" providing real-time stereotactic navigation. A precision ultrasound-powered cutting tool was then integrated into the navigation system and used to perform the osteotomies in each case. Six patients (mean age 52.2 ± 17.7 years, 2 males, 4 females) were included in this study. Negative margins were achieved in all patients with no intraoperative complications. Mean follow-up was 38.0 ± 6.5 months (range, 24.8-42.2). Mean operative time was 1229 min (range, 522-2063). Mean length of stay (LOS) was 18.7 ± 14.5 days. There were no cases of 30-day readmissions, 30-day reoperations, or 2-year mortality. One patient was complicated by flap necrosis, which was successfully treated with irrigation and debridement and primary closure. One patient had local tumor recurrence at final follow-up and two patients are currently undergoing treatment for metastatic disease. Using virtual cutting guides to perform navigated osteotomies is a safe technique that can facilitate complex tumor resections of the sacrum and pelvis.

Risk factors for sacral fracture following en bloc chordoma resection

OBJECTIVE

The purpose of this study was to analyze risk factors for sacral fracture following noninstrumented partial sacral amputation for en bloc chordoma resection.

METHODS

A multicenter retrospective chart review identified patients who underwent noninstrumented partial sacral amputation for en bloc chordoma resection with pre- and postoperative imaging. Hounsfield units (HU) were measured in the S1 level. Sacral amputation level nomenclature was based on the highest sacral level with bone removed (e.g., S1 foramen amputation at the S1-2 vestigial disc is an S2 sacral amputation). Variables collected included basic demographics, patient comorbidities, surgical approach, preoperative radiographic details, neoadjuvant and adjuvant radiation therapy, and postoperative sacral fracture data.

RESULTS

A total of 101 patients (60 men, 41 women) were included; they had an average age of 69 years, BMI of 29 kg/m2, and follow-up of 60 months. The sacral amputation level was S1 (2%), S2 (37%), S3 (44%), S4 (9%), and S5 (9%). Patients had a posterior-only approach (77%) or a combined anterior-posterior approach (23%), with 10 patients (10%) having partial sacroiliac (SI) joint resection. Twenty-seven patients (27%) suffered a postoperative sacral fracture, all occurring between 1 and 7 months after the index surgery. Multivariable logistic regression analysis demonstrated S1 or S2 sacral amputation level (p = 0.001), combined anterior-posterior approach (p = 0.0064), and low superior S1 HU (p = 0.027) to be independent predictors of sacral fracture. The fracture rate for patients with superior S1 HU < 225, 225-300, and > 300 was 38%, 15%, and 9%, respectively. An optimal superior S1 HU cutoff of 300 was found to maximize sensitivity (89%) and specificity (42%) in predicting postamputation sacral fracture. In addition, the fracture rate for patients who underwent partial SI joint resection was 100%.

CONCLUSIONS

Patients with S1 or S2 partial sacral amputations, a combined anterior-posterior surgical approach, low superior S1 HU, and partial SI joint resection are at higher risk for postoperative sacral fracture following en bloc chordoma resection and should be considered for spinopelvic instrumentation at the index procedure.

What Is the Prosthetic Survival After Resection and Intercalary Endoprosthetic Reconstruction for Diaphyseal Bone Metastases of the Humerus and Femur?

BACKGROUND

Large metastatic lesions of the diaphysis can cause considerable pain and result in difficult surgical challenges. Resection and cemented intercalary endoprosthetic reconstruction offer one solution to the problem, but it is an extensive operation that might not be tolerated well by a debilitated patient. The risk of aseptic loosening and revision after intercalary endoprosthetic replacement has varied in previous reports, which have not examined the risk of revision in the context of patient survival.

QUESTIONS/PURPOSES

(1) In a small case series from one institution, what is the survivorship of patients after cemented intercalary endoprosthetic replacement for diaphyseal metastasis, and what is the cumulative incidence of revision for any reason? (2) What are the complications associated with cemented intercalary reconstruction? (3) What is the functional outcome after the procedure as assessed by the MSTS93 score?

METHODS

We retrospectively studied 19 patients with diaphyseal long bone metastases who were treated with resection and cemented intercalary endoprosthetic reconstruction by five participating surgeons at one referral center from 2006 to 2017. There were 11 men and eight women with a median age of 59 years (range 46 to 80 years). The minimum follow-up required for this series was 12 months; however, patients who reached an endpoint (death, radiographic loosening, or implant revision) before that time were included. One of these 19 patients was lost to follow-up but was not known to have died. The median follow-up was 24 months (range 0 to 116 months). Eight of the 19 patients presented with pathologic fractures. Ten of 19 lesions involved the femur, and nine of 19 were in the humerus. The most common pathologic finding was renal cell carcinoma (in 10 of 19). Survival estimates of the patients were calculated using the Kaplan-Meier method. A competing risks estimator was used to evaluate implant survival, using death of the patient as the competing risk. We also estimated the cumulative incidence of aseptic loosening in a competing risk analysis. Radiographs were analyzed for radiolucency at the bone-cement-implant interfaces, fracture, integrity of the cement mantle, and component position stability. Complications were assessed using record review that was performed by an individual who was not involved in the initial care of the patients. Functional outcomes were assessed using the MSTS93 scoring system.

RESULTS

Patient survivorship was 68% (95% CI 50% to 93%) at 1 year, 53% (95% CI 34% to 81%) at 2 years, and 14% (95% CI 4% to 49%) at 5 years; the median patient survival time after reconstruction was 25 months (range 0 to 116 months). In the competing risk analysis, using death as the competing risk, the cumulative incidence of implant revision was 11% (95% CI 2% to 29%) at 1 year and 16% (95% CI 4% to 36%) at 5 years after surgery; however, the cumulative incidence of aseptic loosening (with death as a competing risk) was 22% (95% CI 6% to 43%) at 1 year and 33% (95% CI 13% to 55%) at 5 years after surgery. Other complications included one patient who died postoperatively of cardiac arrest, one patient with delayed wound healing, two patients with bone recurrence, and one patient who experienced local soft tissue recurrence that was excised without implant revision. Total MSTS93 scores improved from a mean of 12.6 ± 8.1 (42% ± 27%) preoperatively to 21.5 ± 5.0 (72% ± 17%) at 3 months postoperatively (p < 0.001) and 21.6 ± 8.5 (72% ± 28%) at 2 years postoperatively (p = 0.98; 3 months versus 2 years).

CONCLUSION

Resection of diaphyseal metastases with intercalary reconstruction can provide stability and short-term improvement in function for patients with advanced metastatic disease and extensive cortical destruction. Aseptic loosening is a concern, particularly in the humerus; however, the competing risk analysis suggests the procedure is adequate for most patients, because many in this series died of disease without undergoing revision.

LEVEL OF EVIDENCE

Level IV, therapeutic study .

The Use of Photodynamic Bone Stabilization to Tamponade Bleeding in a Pathologic Humeral Shaft Fracture: A Case Report

Introduction

Hypervascular tumors such as renal and thyroid carcinoma have a significant risk of intraoperative bleeding. To help mitigate bleeding, interventional preoperative embolization is traditionally used; however, it is success is highly variable. This is the first case report to discuss using expandable balloon implants with a minimally invasive approach to achieve fracture fixation and tamponade acute intraoperative bleeding.

Case Report

A 48-year-old male with clear-cell renal cell carcinoma presented with a left humeral shaft pathologic fracture. The patient was scheduled to undergo open biopsy, curettage of tumor, and fracture fixation with an intramedullary device. Intraoperatively, during open biopsy and curettage, brisk bleeding was encountered, which ceased after inserting an intramedullary photodynamic bone stabilization implant (IlluminOss). The implant's balloon expanded to the diameter of the humerus allowing for tamponade, fracture stability, and a minimally invasive approach.

Conclusion

We present a possible intraoperative option for achieving control of bleeding in pathologic long bone fractures by deploying a photodynamic stabilization device. The method described can have applications in specific patients and obviate the need for pre-operative embolization for highly vascular tumors due to the implant's ability to create tamponade within the bone.

Practice Pattern Variability in the Management of Regional Lymph Node Metastasis in Extremity and Trunk Soft Tissue Sarcoma: A Survey of the Society of Surgical Oncology and Musculoskeletal Tumor Society Membership

BACKGROUND

Regional lymph node metastasis in extremity and trunk soft tissue sarcoma (ETSTS) is rare with no standardized management. We sought to determine management patterns for regional lymph node metastasis in ETSTS.

METHODS

A survey regarding the management of ETSTS lymph node metastasis was distributed to the membership of the Musculoskeletal Tumor Society (MSTS) and the Society of Surgical Oncology (SSO) in January 2022. The survey queried the type of training (surgical oncology, orthopedic oncology), details of their practice setting, and management decisions of hypothetical ETSTS scenarios that involved potential or confirmed lymph node metastasis.

RESULTS

The survey was distributed to 349 MSTS members (open rate of 63%, completion rate 21%) and 3026 SSO members (open rate of 55%, completion rate 4.7%) and was completed by 214 respondents, of whom 73 (34.1%) and 141 (65.9%) were orthopedic oncology and surgical oncology fellowship-trained, respectively. The majority of respondents practiced in an academic setting (n = 171, 79.9%) and treat >10 extremity sarcoma cases annually (n = 138, 62.2%). In scenarios with confirmed nodal disease for clear cell and epithelioid sarcoma, surgical oncologists were inclined to perform lymphadenectomy, while orthopedic oncologists were inclined to offer targeted lymph node excision with adjuvant radiation (p < 0.001). There was heterogeneity of responses regarding the management of nodal disease regardless of training background.

CONCLUSION

Self-reported management of nodal disease in ETSTS was variable among respondent groups with differences and similarities based on training background. These data highlight the variability of practice for nodal disease management and the need for consensus-based guidelines.

Hypofractionated, 3-week, preoperative radiotherapy for patients with soft tissue sarcomas (HYPORT-STS): a single-centre, open-label, single-arm, phase 2 trial

BACKGROUND

The standard preoperative radiotherapy regimen of 50 Gy delivered in 25 fractions for 5 weeks for soft tissue sarcomas results in excellent local control, with major wound complications occurring in approximately 35% of patients. We aimed to investigate the safety of a moderately hypofractionated, shorter regimen of radiotherapy, which could be more convenient for patients.

METHODS

This single-centre, open-label, single-arm, phase 2 trial (HYPORT-STS) was done at a single tertiary cancer care centre (MD Anderson Cancer Center, Houston, TX, USA). We administered preoperative radiotherapy to a dose of 42·75 Gy in 15 fractions of 2·85 Gy/day for 3 weeks (five fractions per week) to adults (aged ≥18 years) with non-metastatic soft tissue sarcomas of the extremities or superficial trunk and an Eastern Cooperative Oncology Group performance status of 0-3. The primary endpoint was a major wound complication occurring within 120 days of surgery. Major wound complications were defined as those requiring a secondary operation, or operations, under general or regional anaesthesia for wound treatment; readmission to the hospital for wound care; invasive procedures for wound care; deep wound packing to an area of wound measuring at least 2 cm in length; prolonged dressing changes; repeat surgery for revision of a split thickness skin graft; or wet dressings for longer than 4 weeks. We analysed our primary outcome and safety in all patients who enrolled. We monitored safety using a Bayesian, one-arm, time-to-event stopping rule simulator comparing the rate of major wound complications at 120 days post-surgery among study participants with the historical rate of 35%. This trial is registered with ClinicalTrials.gov, NCT03819985, recruitment is complete, and follow-up continues.

FINDINGS

Between Dec 18, 2018, and Jan 6, 2021, we assessed 157 patients for eligibility, of whom 120 were enrolled and received hypofractionated preoperative radiotherapy. At no time did the stopping rule computation indicate that the trial should be stopped early for lack of safety. Median postoperative follow-up was 24 months (IQR 17-30). Of 120 patients, 37 (31%, 95% CI 24-40) developed a major wound complication at a median time of 37 days (IQR 25-59) after surgery. No patient had acute radiation toxicity (during radiotherapy or within 4 weeks of the radiotherapy end date) of grade 3 or worse (Common Terminology Criteria for Adverse Events [CTCAE] version 4.0) or an on-treatment serious adverse event. Four (3%) of 115 patients had late radiation toxicity (≥6 months post-surgery) of at least grade 3 (CTCAE or Radiation Therapy Oncology Group/European Organisation for Research and Treatment of Cancer Late Radiation Morbidity Scoring Scheme): femur fractures (n=2), lymphoedema (n=1), and skin ulceration (n=1). There were no treatment-related deaths.

INTERPRETATION

Moderately hypofractionated preoperative radiotherapy delivered to patients with soft tissue sarcomas was safe and could therefore be a more convenient alternative to conventionally fractionated radiotherapy. Patients can be counselled about these results and potentially offered this regimen, particularly if it facilitates care at a sarcoma specialty centre. Results on long-term oncological, late toxicity, and functional outcomes are awaited.

FUNDING

The National Cancer Institute.

Abstract PR002: Antigen presentation and processing pathway is associated with early relapse after neoadjuvant immune checkpoint blockade (ICB) in dedifferentiated liposarcomas (DDLPS)

Background: We evaluated the activity of neoadjuvant ICB in localized resectable DDLPS (n=17) and undifferentiated pleomorphic sarcomas (UPS; n=10). DDLPS and UPS patients were randomized to neoadjuvant nivolumab or ipilimumab+nivolumab, with UPS patients receiving concurrent radiotherapy. We assessed genomic markers of early relapse (progression before surgery or relapse within 52 weeks following surgery) using longitudinally acquired tumor samples. Methods: RNA sequencing (RNAseq) and whole genome sequencing (WGS) were performed on longitudinally acquired samples (baseline biopsies and surgical specimens). Differential gene expression between any two groups of patients (i.e., non-early relapse [non-relapsers] vs early relapse [relapsers]) were selected (fold change&gt;1.5 and p value&lt;0.05). Gene set enrichment analyses (GSEA) of KEGG pathways were performed and a network-based approach used to identify genes/pathways associated with MHC-I. Results: At a median follow-up of 23 months, 12 patients (9 DDLPS, 3 UPS) relapsed, including 7 early relapses (relapsers: 5 DDLPS, 2 UPS). The median relapse-free survival was 22 months in DDLPS patients (6 months in relapsers; not reached [NR] in non-relapsers) and NR in UPS patients. At baseline, the most differentially upregulated pathways in non-relapsers compared to relapsers were “graft versus host disease” (GSEA Normalized Enrichment Score[NES]=2.25; False Discovery Rate[FDR] q= 0.009), “natural killer cell mediated cytotoxicity” (NES=2.17; FDR q=0.009), “antigen processing and presentation” (NES=2.16; FDR q=0.009), “allograft rejection” (NES=1.99; FDR q=0.019) and “B-cell receptor signaling pathway” (NES=1.87; FDR q=0.018). In DDLPS patients, the antigen presentation and processing pathway was the most upregulated pathway in non-relapsers compared to relapsers (NES=2.01; FDR q=0.025) while it was not significantly upregulated in UPS (NES=1.15; FDR q=0.62). When looking at pathways longitudinally, the antigen presentation and processing pathway was significantly upregulated at surgery compared to baseline in DDLPS. As antigen presentation and processing was significantly upregulated in DDLPS patients and associated with relapse, we looked for expressed neoantigens that may be processed and presented. Using WGS, we detected 5712 rearrangements at baseline in DDLPS, of which 230 were found in more than one tumor specimen. We also sought to identify genes associated with MHC-I. We selected genes upregulated during ICB comparing baseline to surgical specimens in DDLPS relapsers and looked at the top 10% of genes associated with MHC-I in order to identify potential therapeutic targets for combination. We identified 41 genes upregulated during ICB and associated with MHC-I in relapsers, for which up to 275 inhibitory compounds were found in drug databases. Conclusion: Antigen presentation and processing is a major driver of response to immunotherapy. Future efforts should focus on identifying which antigens are presented to find synergizing compounds in order to increase the clinical benefit of ICB.

Citation Format: Elise F. Nassif, Chia-Chin Wu, Kadir Akdemir, Russell G. Witt, Raymond Traweek, Brandon Cope, Prapassorn Thirasastr, Taylor Tate, Grace Mathew, Shadarra Crosby, Randy Chu, Mohammad Mohammad, Kenna Shaw, Ingram Davis, Khalida Wani, Alexander J. Lazar, Wei-Lien Wang, Sheila Duncan, Ashleigh B. Guadagnolo, Andrew J. Bishop, Valerae Lewis, Justin E. Bird, Keila E. Torres, Kelly K. Hunt, Barry W. Feig, Christopher P. Scally, Ravin Ratan, Shreyaskumar Patel, Robert S. Benjamin, Robert Satcher, Kevin McBride, Wolf H. Fridman, Ignacio Wistuba, Andrew Futreal, Jennifer A. Wargo, Neeta Somaiah, Christina L. Roland, Emily Z. Keung. Antigen presentation and processing pathway is associated with early relapse after neoadjuvant immune checkpoint blockade (ICB) in dedifferentiated liposarcomas (DDLPS) [abstract]. In: Proceedings of the AACR Special Conference: Sarcomas; 2022 May 9-12; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(18_Suppl):Abstract nr PR002.

Randomized phase II study of neoadjuvant checkpoint blockade for surgically resectable undifferentiated pleomorphic sarcoma (UPS) and dedifferentiated liposarcoma (DDLPS): Survival results after 2 years of follow-up and intratumoral B-cell receptor (BCR) correlates

LBA11501

Background: We conducted a randomized, phase II non-comparative trial evaluating the efficacy of neoadjuvant ICB [nivolumab or ipilimumab/nivolumab] in patients (pts) with surgically resectable retroperitoneal DDLPS or extremity/truncal UPS treated with concurrent neoadjuvant radiation therapy (XRT, UPS only). Methods: As of February 28 2022, all pts have a minimum follow-up of 2 years from the start of ICB treatment. Progression-free survival (PFS) and overall survival (OS) were calculated using Kaplan Meier method. The association of pathologic response (percent hyalinization and viable tumor at surgery) with PFS and OS was assessed using Cox univariate models. Comparison of survival curves was done by log-rank method. The intratumoral BCR repertoire was evaluated by bulk tumor RNA sequencing with TRUST4 algorithm, on biopsy specimens collected at baseline. Description of the intratumoral BCR repertoire included diversity by inverse Simpson index, and clonal distribution by Gini coefficient. High and low categories were defined by median values. Results: At a median follow-up of 31 months (interquartile range [IQR]=27-43) since start of ICB treatment, the median PFS was not reached (NR) in UPS (IQR=19-NR) and 18 months for DDLPS (IQR=8-NR), with 13 pts experiencing relapse (2 UPS, 11 DDLPS) and 2 pts who had progressive metastatic disease on treatment (1 UPS, 1 DDLPS). Five pts died of disease relapse (1 UPS, 4 DDLPS) and the median OS was NR. There was no association between percent hyalinization at surgery and PFS (Hazard Ratio [HR]=0.98, p=0.12) or OS (HR=0.99, p=0.60) nor between percent viable tumor at surgery and PFS (HR=1.00, p=0.62) or OS (HR=1.00, p=0.67). There was no association between RECIST response and PFS (p=0.67) or OS (p=0.67). The median BCR heavy chain (IgH) clonal counts detected at baseline was 2,536 per sample (IQR=82-7,680), and the median BCR light chain (IgL) clonal count was 8,870 per sample (IQR=306-30,214). Pts with higher intratumoral BCR clonality and diversity at baseline tended to have longer PFS (Table). High BCR IgH clonality was significantly associated with OS (p=0.02) with consistent trends in each histotype (DDLPS: p=0.06; UPS: p=0.25). Conclusions: Survival results demonstrate efficacy of ICB with XRT in UPS but there is a crucial need to define better predictive markers of survival after neoadjuvant therapy. Further characterization of the BCR repertoire is ongoing and will be presented at the meeting. Clinical trial information: NCT03307616. [Table: see text]

Free Vascularized Fibula Flap Reconstruction of Total and Near-total Destabilizing Resections of the Sacrum

BACKGROUND

Vascularized bone grafts (VBGs) are associated with improved union and fewer instrumentation complications in the mobile spine. It is not known if VBGs are similarly efficacious after sacrectomy.

METHODS

We conducted a retrospective chart review of all patients who underwent total sacrectomy and immediate reconstruction with VBG between 2005 and 2019. Patient and surgical characteristics in addition to union and functional outcomes were analyzed.

RESULTS

We identified 10 patients (6 women and 4 men) with a mean age of 42 years (range, 12-71 years). All patients received iliolumbar instrumentation as well as a free fibula flap as a VBG. There were no complications at the fibula flap donor site or specifically related to the VBG. Bony union was achieved in 7 (88%) of 8 patients with an average union time of 6.3 months (range, 2-10 months). Surgical complications occurred in 5 patients, 4 patients required reoperation for wound dehiscence, and 1 patient required conversion to a 4-rod construct and bone grafting for instrumentation loosening and partial nonunion. Instrumentation failure developed in 1 patient, but no surgical intervention was required. One patient was able to walk independently without any limitation, 5 patients required a walker, 2 were wheelchair-bound except for short (<15 ft) distances, and 2 were lost to follow-up.

CONCLUSIONS

The free vascularized fibula flap is a safe and effective option for supplementing spinal reconstruction after destabilizing sacrectomy.

Osteoid Tumors of Bone

We present a review of several bone (osteoid)-forming tumors including enostosis, osteoid osteoma, osteoblastoma, and osteosarcoma. These entities were chosen because they are reasonably common-neither seen every day nor rare. When applicable, recent information about the lesions is included.

Surgical drainage after limb salvage surgery and endoprosthetic reconstruction: is 30 mL/day critical?

Background

Periprosthetic infection is a major cause of failure after segmental endoprosthetic reconstruction. The purpose of this study is to determine whether certain aspects of drain output affect infection risk, particularly the 30 mL/day criterion for removal.

Methods

Two hundred and ninety-five patients underwent segmental bone resection and lower limb endoprosthetic reconstruction at one institution. Data on surgical drain management and occurrence of infection were obtained from a retrospective review of patients’ charts and radiographs. Univariate and multivariate Cox regression analyses were performed to identify factors associated with infection.

Results

Thirty-one of 295 patients (10.5%) developed infection at a median time of 13 months (range 1–108 months). Staphylococcus aureus was the most common organism and was responsible for the majority of cases developing within 1 year of surgery. Mean output at the time of drain removal was 72 mL/day. Ten of 88 patients (11.3%) with ≤ 30 mL/day drainage and 21 of 207 patients (10.1%) with > 30 mL/day drainage developed infection (p = 0.84). In multivariate analysis, independent predictive factors for infection included sarcoma diagnosis (HR 4.13, 95% CI 1.4–12.2, p = 0.01) and preoperative chemotherapy (HR 3.29, 95% CI 1.1–9.6, p = 0.03).

Conclusion

Waiting until drain output is < 30 mL/day before drain removal is not associated with decreased risk of infection for segmental endoprostheses of the lower limb after tumor resection. Sarcoma diagnosis and preoperative chemotherapy were independent predictors of infection.

Use of a rapid access multidisciplinary bone metastases clinic to decrease financial toxicity for patients undergoing single-fraction palliative radiation

24

Background: A rapid access bone metastases clinic (RABC) was instituted at MD Anderson Cancer Center (MDACC) to allow outpatient consult, simulation and radiation treatment (RT) initiation in < 6 hours for patients with painful bone metastases. Patients underwent multidisciplinary evaluation with orthopedics and radiation oncology. One aspect of financial toxicity is distress due to out-of-pocket (OOP) cost associated with a treatment. We hypothesized the RABC would decrease financial toxicity for MDACC patients over traditional RT. Methods: RABC patients surveyed between April 2018 and January 2020 were included. Patients were asked to estimate OOP cost for RT (including travel and treatment cost) and perceived cost burden of treatment. Travel distance was hometown distance to MDACC. Subset analyses were performed for patients receiving single fraction (1fx) and 2-5 fractions (2-5fx). Estimated OOP cost (1fx: RABCN= 34, nonRABCN= 20; 2-5fx: RABCN= 4, nonRABCN= 22), perceived cost burden (1fx: RABCN= 32, nonRABCN= 27; 2-5fx: RABCN= 7, nonRABCN= 38) and travel distance (1fx: RABCN= 34, nonRABCN= 28; 2-5fx: RABCN= 7, nonRABCN= 38) were compared using a Mann-Whitney U Test. Travel distance was also compared to OOP cost. Patients treated with 6+ fractions were excluded. Results: Median estimated OOP cost was significantly lower for 1fx RABC patients vs. 1fx non-RABC patients ($450 [IQR $187.5-$1,050] vs. $2,000 [$625-$4,000]; p = 0.008), but there was no significant difference for 2-5fx ($1,900 vs. $1,375; p = 0.593). Overall patient satisfaction with cost burden was high regardless of treatment setting (1fx: 10 [8-10]; 2-5fx: 10 [8-10]). Median travel distance was not significantly different between clinics (1fx: 245 [39.8-351.5] vs. 262.5 [83-879.3], p = 0.3651; 2-5fx: 274 [36-1293] vs. 176 [25-626], p = 0.2721). Travel distance was directly correlated with out of pocket cost for single fraction (1fx: R2= 0.125, p = 0.0109; 2-5fx: R2= 0.037, p = 0.3433). Conclusions: The establishment of a RABC at MDACC significantly decreased financial toxicity for 1fx patients receiving palliative RT, but not in the 2-5fx cohort. Increased financial toxicity was associated with longer travel distance for 1fx palliative radiation. Implementation of a similar model in local community centers may decrease financial toxicity for patients receiving palliative radiation.

Cancer Surgery Scheduling During and After the COVID-19 First Wave: The MD Anderson Cancer Center Experience

OBJECTIVE

To summarize the multi-specialty strategy and initial guidelines of a Case Review Committee in triaging oncologic surgery procedures in a large Comprehensive Cancer Center and to outline current steps moving forward after the initial wave.

SUMMARY OF BACKGROUND DATA

The impetus for strategic rescheduling of operations is multifactorial and includes our societal responsibility to minimize COVID-19 exposure risk and propagation among patients, the healthcare workforce, and our community at large. Strategic rescheduling is also driven by the need to preserve limited resources. As many states have already or are considering to re-open and relax stay-at-home orders, there remains a continued need for careful surgical scheduling because we must face the reality that we will need to co-exist with COVID-19 for months, if not years.

METHODS

The quality officers, chairs, and leadership of the 9 surgical departments in our Division of Surgery provide specialty-specific approaches to appropriately triage patients.

RESULTS

We present the strategic approach for surgical rescheduling during and immediately after the COVID-19 first wave for the 9 departments in the Division of Surgery at The University of Texas MD Anderson Cancer Center in Houston, Texas.

CONCLUSIONS

Cancer surgeons should continue to use their oncologic knowledge to determine the window of opportunity for each surgical procedure, based on tumor biology, preoperative treatment sequencing, and response to systemic therapy, to safely guide patients through this cautious recovery phase.

Preliminary results of a phase II study of neoadjuvant checkpoint blockade for surgically resectable undifferentiated pleomorphic sarcoma (UPS) and dedifferentiated liposarcoma (DDLPS)

11505

Background: is a randomized, phase II non-comparative trial evaluating the efficacy of neoadjuvant checkpoint blockade [nivolumab (N) or ipilimumab/ nivolumab (I/N)] in patients (pts) with surgically resectable retroperitoneal DDLPS or extremity/truncal UPS treated with concurrent neoadjuvant radiation therapy (RT, UPS only). Methods: Primary endpoint was pathologic (path) response. Secondary endpoints were safety, RECIST response, recurrence-free survival, overall survival and patient-reported outcomes. Biospecimens (tumor, blood, fecal microbiome) at baseline, on therapy, and at time of surgery were collected and will be assessed for immune-based prognostic biomarkers. We assessed correlation between radiographic and pathologic response by linear regression. Correlative analyses includes assessment of tumor PD-L1 expression, characterization of tumor immune infiltrates by multiplex immunohistochemistry, and transcriptomic and genomic analyses. Results: Of the 25 pts enrolled; 24 are evaluable for response (14 DDLPS, 9 UPS). Clinical activity was variable by histologic subtype and treatment with RT. Median path response in the UPS cohort was 95% [95% CI 85–99] and was similar between the N/RT and I/N/RT groups (Table). Median path response in the DDLPS cohort was 22.5% [95% CI 85–99; Table]. Median change in tumor size (radiographic response) was -4% and +9% in the UPS and DDLPS cohorts, respectively. There was no correlation between path response and radiographic response (R2 0.0309; p = 0.43). Of 8 pts with path response ≥ 85%, there was 1 partial response, 5 stable disease and 2 progressive disease by RECIST criteria. There was 1 delay to surgery due to grade 3 hyperbilirubinemia (Arm B). There was no difference in toxicity between N/RT and I/N/RT. Conclusions: N/RT and I/N/RT have significant clinical activity in UPS; more than expected compared to historic controls. Toxicity profiles were as expected and the majority of patients underwent resection without delay. Larger studies evaluating N/RT in UPS are warranted given the significant path response in this cohort. RECIST was not associated with path response and better markers of on-treatment clinical activity are needed. Correlative analyses that may guide combination strategies are ongoing and will be presented at the meeting. Clinical trial information: NCT03307616 .

Single-Fraction Stereotactic vs Conventional Multifraction Radiotherapy for Pain Relief in Patients With Predominantly Nonspine Bone Metastases: A Randomized Phase 2 Trial

Importance

Consensus is lacking as to the optimal radiotherapy dose and fractionation schedule for treating bone metastases.

Objective

To assess the relative efficacy of high-dose, single-fraction stereotactic body radiotherapy (SBRT) vs standard multifraction radiotherapy (MFRT) for alleviation of pain in patients with mostly nonspine bone metastases.

Design, Setting, and Participants

This prospective, randomized, single-institution phase 2 noninferiority trial conducted at a tertiary cancer care center enrolled 160 patients with radiologically confirmed painful bone metastases from September 19, 2014, through June 19, 2018. Patients were randomly assigned in a 1:1 ratio to receive either single-fraction SBRT (12 Gy for ≥4-cm lesions or 16 Gy for <4-cm lesions) or MFRT to 30 Gy in 10 fractions.

Main Outcomes and Measures

The primary end point was pain response, defined by international consensus criteria as a combination of pain score and analgesic use (daily morphine-equivalent dose). Pain failure (ie, lack of response) was defined as worsening pain score (≥2 points on a 0-to-10 scale), an increase in morphine-equivalent opioid dose of 50% or more, reirradiation, or pathologic fracture. We hypothesized that SBRT was noninferior to MFRT.

Results

In this phase 2 noninferiority trial of 96 men and 64 women (mean [SD] age, 62.4 [10.4] years), 81 patients received SBRT and 79 received MFRT. Among evaluable patients who received treatment per protocol, the single-fraction group had more pain responders than the MFRT group (complete response + partial response) at 2 weeks (34 of 55 [62%] vs 19 of 52 [36%]) (P = .01), 3 months (31 of 43 [72%] vs 17 of 35 [49%]) (P = .03), and 9 months (17 of 22 [77%] vs 12 of 26 [46%]) (P = .03). No differences were found in treatment-related toxic effects or quality-of-life scores after SBRT vs MFRT; local control rates at 1 and 2 years were higher in patients receiving single-fraction SBRT.

Conclusions and Relevance

Delivering high-dose, single-fraction SBRT seems to be an effective treatment option for patients with painful bone metastases. Among evaluable patients, SBRT had higher rates of pain response (complete response + partial response) than did MFRT and thus should be considered for patients expected to have relatively long survival.

Trial Registration

ClinicalTrials.gov identifier: NCT02163226.

Postoperative Radiotherapy for Multiple Myeloma of Long Bones: Should the Entire Rod Be Treated?

PURPOSE

To characterize local relapse after surgical fixation and postoperative radiotherapy (RT) for multiple myeloma (MM) with cortical involvement of long bones.

PATIENTS AND METHODS

We retrospectively identified patients with MM involving cortical long bones treated with surgical fixation followed by postoperative RT at our institution. Local failures, defined as radiographic recurrence along the surgical hardware, were documented, and potential associations of independent variables (RT dose, fractionation, and extent of hardware coverage) with local failure were assessed by univariate Cox regression.

RESULTS

We identified 33 patients with 40 treated sites with a median follow-up of 25.7 months; 68% of treatments were for pathologic fracture, and 32% were for impending fracture. The most common dose and fractionation were 20 to 25 Gy in 8 to 12 fractions. On average, 76% of the surgical hardware was covered by the postoperative RT field (median, 80%; range, 28%-100%). Local failure was observed in 5 cases (12.5%), 2 within the RT field and 3 out of field. None of the relapses resulted in hardware failure, and 2 were retreated with RT. The extent of hardware coverage predicted disease relapse along the hardware (hazard ratio = 6.44; 95% confidence interval, 1.09-37.97; P = .04); however, total RT dose, biologically effective dose, and number of fractions did not.

CONCLUSION

After internal fixation of long bones with MM, full hardware coverage with the RT field could reduce the risk, though small, of disease developing in the future in the proximate hardware. Postoperative RT doses of 20 to 25 Gy in 8 to 10 fractions can achieve excellent local control.

Single-fraction stereotactic versus standard conventional multifraction radiation for predominantly non-spine bone metastases: A randomized phase II trial

11578

Background: There lacks a consensus as to the optimal radiotherapy dose and fractionation schedule for treating bone metastases. We assessed the relative efficacy of single high-dose stereotactic radiation therapy (SBRT) versus standard multifraction radiation therapy (MFRT) for alleviation of pain in patients with mostly non-spine bone metastases. Methods: This prospective, randomized, single-institution phase II non-inferiority trial enrolled patients with radiologically confirmed painful bone metastases from September 2014 through June 2018. Patients were randomly assigned in a 1:1 ratio to receive either single-fraction SBRT (12 Gy for ≥4-cm lesions or 16 Gy for < 4-cm lesions) versus MFRT to 30 Gy in 10 fractions. Results: The primary endpoint was pain response, defined by international consensus criteria as a combination of pain score and analgesic use (daily morphine-equivalent dose [MED]). Failure of pain response was defined as worsening pain score (≥2 points on a 0-to-10 scale), an increase in morphine-equivalent opioid dose of ≥50%; re-irradiation; or pathologic fracture. Among evaluable patients who received treatment per protocol, the single-fraction SBRT group had more pain responders (CR+PR) at 2 weeks (62% vs. 36% MFRT, P= 0.01), at 1 month (62% vs 36%, P= 0.01), at 3 months (72% vs. 49% MFRT, P= 0.03), and at 9 months (77% vs. 12% MFRT, P= 0.03). No differences were found in treatment-related toxicity or quality of life scores after SBRT versus MFRT; local control rates at 1 year were higher in patients receiving single-fraction SBRT. Conclusions: Delivering high-dose single-fraction SBRT is an effective, convenient treatment option for patients with painful bone metastases. Among evaluable patients, SBRT led to higher rates of pain response (CR+PR) than did MFRT and thus should be considered for patients expected to have relatively long survival. Clinical trial information: ClinicalTrials.gov ID NCT02163226.

Implementation of a rapid access multidisciplinary bone metastases clinic to improve access to care at a large cancer center

79

Background: MD Anderson Cancer Center is a large cancer center with 44,000 new patients per year. Radiation therapy (RT) is an effective treatment for bone metastases that can reduce pain medication use and improve quality of life. Our goal was to assess the effect of implementing a rapid access multidisciplinary clinic for bone metastases (RABC). Methods: RABC was instituted to schedule patients for radiation oncology and orthopedic surgery consult within 48 hours of referral. Same day simulation and treatment times were held for these patients for one 8Gy fraction. Thirty sequential patients treated with one fraction to bony sites in the outpatient setting prior to implementation of the clinic were chosen as a comparison group. Time from consult order to consult visit (OTV) and from consult visit to treatment completion (CTT) were recorded, in addition to frequency of multidisciplinary care (MDC; orthopedic surgery and radiation oncology). Overall Time (OT) was calculated from referral to treatment completion. T-test and chi-square test were used for analyses. Results: Between April 2018 and July 2018, 72 patients were referred to RABC. 23 patients were seen in consultation and received RT. Sites treated were pelvis (N = 10), spine (N = 6), lower extremity (N = 4) and upper extremity (N = 3). Patients had one site (N = 20), two sites (N = 2) or three sites treated (N = 1). Histologies included breast (N = 5), thoracic (N = 7), gastrointestinal (N = 6), genitourinary (N = 2) and head/neck (N = 2). OTV was shorter for RABC patients (mean 3.3 [+/-5.7] vs. 9.5 days [12.4]; p = 0.02). CTT was also significantly shorter for RABC patients (mean 5.4 hours [+/-1.8] vs. 6.5 days [+/-6.5]; p < .0001). OT was also shorter (3.5 days [+/-5.6] vs. 16.4 days [+/-14.8]; p < .0001). RABC clinic patients were more likely to receive MDC (100% vs 28%; p < .0001). Conclusions: The rapid access bone metastases clinic significantly decreased overall time from consult to completion of treatment and also decreased time to access radiotherapy. Patients were also more likely to receive multidisciplinary evaluation. The RABC approach is a promising model to improve palliation for patients with painful bony metastases.

Implementation of an Enhanced Recovery After Spine Surgery program at a large cancer center: a preliminary analysis

OBJECTIVE

Enhanced Recovery After Surgery (ERAS) programs follow a multimodal, multidisciplinary perioperative care approach that combines evidence-based perioperative strategies to accelerate the functional recovery process and improve surgical outcomes. Despite increasing evidence that supports the use of ERAS programs in gastrointestinal and pelvic surgery, data regarding the development of ERAS programs in spine surgery are scarce. To evaluate the impact of an Enhanced Recovery After Spine Surgery (ERSS) program in a US academic cancer center, the authors introduced such a program and hypothesized that ERSS would have a significant influence on meaningful clinical measures of postoperative recovery, such as pain management, postoperative length of stay (LOS), and complications.

METHODS

A multimodal, multidisciplinary, continuously evolving team approach was used to develop an ERAS program for all patients undergoing spine surgery for metastatic tumors at The University of Texas MD Anderson Cancer Center from April 2015 through September 2016. This study describes the introduction of that ERSS program and compares 41 patients who participated in ERSS with a retrospective cohort of 56 patients who underwent surgery before implementation of the program. The primary objectives were to assess the effect of an ERSS program on immediate postoperative pain scores and in-hospital opioid consumption. The secondary objectives included assessing the effect of ERSS on postoperative in-hospital LOS, 30-day readmission rates, and 30-day postoperative complications.

RESULTS

The ERSS group showed a trend toward better pain scores and decreased opioid consumption compared with the pre-ERSS group. There were no significant differences in LOS, 30-day readmission rate, or 30-day complication rate observed between the two groups.

RESULTS

An ERSS program is feasible and potentially effective on perioperative pain control and opioid consumption, and can expedite recovery in oncological spine surgery patients. Larger-scale research on well-defined postoperative recovery outcomes is needed.

BIGH3 Promotes Osteolytic Lesions in Renal Cell Carcinoma Bone Metastasis by Inhibiting Osteoblast Differentiation

BACKGROUND: Bone metastasis is common in renal cell carcinoma (RCC), and the lesions are mainly osteolytic. The mechanism of bone destruction in RCC bone metastasis is unknown. METHODS: We used a direct intrafemur injection of mice with bone-derived 786-O RCC cells (Bo-786) as an in vivo model to study if inhibition of osteoblast differentiation is involved in osteolytic bone lesions in RCC bone metastasis. RESULTS: We showed that bone-derived Bo-786 cells induced osteolytic bone lesions in the femur of mice. We examined the effect of conditioned medium of Bo-786 cells (Bo-786 CM) on both primary mouse osteoblasts and MC3T3-E1 preosteoblasts and found that Bo-786 CM inhibited osteoblast differentiation. Secretome analysis of Bo-786 CM revealed that BIGH3 (Beta ig h3 protein), also known as TGFBI (transforming growth factor beta-induced protein), is highly expressed. We generated recombinant BIGH3 and found that BIGH3 inhibited osteoblast differentiation in vitro. In addition, CM from Bo-786 BIGH3 knockdown cells (786-BIGH3 KD) reduced the inhibition of osteoblast differentiation compared to CM from vector control. Intrafemural injection of mice with 786-BIGH3 KD cells showed a reduction in osteolytic bone lesions compared to vector control. Immunohistochemical staining of 18 bone metastasis specimens from human RCC showed strong BIGH3 expression in 11/18 (61%) and moderate BIGH3 expression in 7/18 (39%) of the specimens. CONCLUSIONS: These results suggest that suppression of osteoblast differentiation by BIGH3 is one of the mechanisms that enhance osteolytic lesions in RCC bone metastasis, and raise the possibilty that treatments that increase bone formation may improve therapy outcomes.

Non-Radiographic Risk Factors Differentiating Atypical Lipomatous Tumors from Lipomas

PURPOSE

To determine non-radiographic risk factors differentiating atypical lipomatous tumors (ALTs) from lipomas.

METHODS

All patients with deep-seated lipomatous tumors of the extremities treated from January 2000 to October 2010 were retrospectively reviewed. Factors reviewed included age, gender, tumor location, size, histology, local recurrence, dedifferentiation, and metastasis. Multivariate logistic regression models were used to evaluate the effects of patient characteristics on ALT status.

RESULTS

Ninety-four lipomas and 46 ALTs were included. Patients with an ALT were older (median: 60.5 vs. 55 years). Lipomas were evenly distributed between upper (48.9%) and lower extremities (51.1%), whereas ALTs predominately involved the lower extremities (91.3%). Median ALT size (22 cm) was greater than lipomas (10 cm), p < 0.0001. One lipoma (1.04%) recurred at 77 months and five ALTs (10.9%) recurred at an average of 39 months (19-64 months). Two ALTs originally treated with wide resection recurred with a dedifferentiated component and were treated with wide re-excision and chemotherapy. No metastases or tumor-related deaths occurred in either group at the time of last follow-up. Patients older than 60 years, tumors greater than 10 cm, or thigh location, were more likely to be diagnosed with an ALT (p < 0.05).

CONCLUSION

Lipomatous tumors were more likely to be ALTs when the tumor was at least 10 cm in size, located in the thigh, or found in patients that were 60 years of age or older. These risk factors may be used to guide management and surveillance strategies, when lipomatous tumors do not display characteristic radiographic features.

Patellar Resurfacing: Does It Affect Outcomes of Distal Femoral Replacement After Distal Femoral Resection?

BACKGROUND

Patellar resurfacing after routine arthroplasty remains controversial. Few studies have specifically examined the effect of patellar resurfacing on outcomes after resection of the distal part of the femur and reconstruction with a megaprosthesis. Our objective was to compare the outcomes of megaprosthesis reconstructions of the distal part of the femur with and without patellar resurfacing after resection of a distal femoral tumor.

METHODS

We retrospectively reviewed the clinical records of patients with a femoral tumor who underwent resection of the distal part of the femur and endoprosthetic reconstruction between 1993 and 2013. We excluded patients who had had extra-articular knee resection, patellectomy, revision, reconstruction with an expandable prosthesis, or a proximal tibial replacement associated with the distal femoral replacement. We compared demographic characteristics, surgical variables, anterior knee pain, range of motion, extensor lag, Insall-Salvati ratio, Insall-Salvati patellar tendon insertion ratio, impingement, patellar degenerative disease, additional patellar procedures, complications, and Musculoskeletal Tumor Society (MSTS) score between the patellar resurfacing and nonresurfacing groups.

RESULTS

One hundred and eight patients--sixty without patellar resurfacing and forty-eight with patellar resurfacing--were included in the study. The mean age was 33.9 years (range, twelve to seventy-five years). There were fifty-four men and fifty-four women. The mean duration of follow-up was 4.5 years (range, 0.7 to twenty years). There was no significant difference in anterior knee pain between the groups (p = 0.51). Anterior knee pain did not significantly affect the range of motion, extensor lag, or reoperation or complication rate. Patellar degenerative disease occurred in 48% of the nonresurfaced knees but was not associated with focal pain. Complication rates were similar in the two groups, although peripatellar calcifications were significantly more common in the resurfacing group (19% versus 2%; p = 0.005). There was no significant difference in the mean MSTS score between the nonresurfacing (81%) and resurfacing (71%) groups (p = 0.34).

CONCLUSIONS

There were no differences in anterior knee pain, range of motion, extensor lag, or MSTS score between the patients with and those without patellar resurfacing. There were no cases of patellar component loosening or revision. In light of the similar outcomes in the two groups, the decision to resurface should be left up to the individual surgeon, who should take into account preoperative peripatellar pain and the status of the patella at the time of resection.

LEVEL OF EVIDENCE

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

Tibial Growth Disturbance Following Distal Femoral Resection and Expandable Endoprosthetic Reconstruction

BACKGROUND

In growing children, an expandable endoprosthesis is commonly used after distal femoral resection to compensate for loss of the distal femoral physis. Our hypothesis was that such prostheses can affect proximal tibial growth, which would contribute to an overall leg-length discrepancy and cause angular deformity.

METHODS

Twenty-three skeletally immature patients underwent the placement of a distal femoral expandable endoprosthesis between 1994 and 2012. Tibial length, femoral length, and mechanical axis were measured radiographically to determine the growth rate.

RESULTS

No patient had radiographic evidence of injury to the proximal tibial physis at the time of surgery other than insertion of the tibial stem. Fifteen (65%) of the patients experienced less proximal tibial growth in the operative compared with the contralateral limb. In ten (43%) of the patients, the discrepancy progressively worsened, whereas in five (22%) of the patients, the discrepancy stabilized. Seven patients did not develop tibial length discrepancy, and one patient had overgrowth of the tibia. For the ten patients with progressive shortening, the proximal tibial physis grew an average of 4.0 mm less per year in the operative limb. Five (22%) of the patients had ≥ 20 mm of tibial length discrepancy at last follow-up. Three of these patients underwent contralateral tibial epiphysiodesis. Three patients required corrective surgery for angular deformity.

CONCLUSIONS

The tibial growth plate may not resume normal growth after implantation of a distal femoral prosthesis. Physeal bar resection, prosthesis revision, and contralateral tibial epiphysiodesis may be needed to address tibial growth abnormalities.

Intratumoral injection of Clostridium novyi-NT spores induces antitumor responses

Species of Clostridium bacteria are notable for their ability to lyse tumor cells growing in hypoxic environments. We show that an attenuated strain of Clostridium novyi (C. novyi-NT) induces a microscopically precise, tumor-localized response in a rat orthotopic brain tumor model after intratumoral injection. It is well known, however, that experimental models often do not reliably predict the responses of human patients to therapeutic agents. We therefore used naturally occurring canine tumors as a translational bridge to human trials. Canine tumors are more like those of humans because they occur in animals with heterogeneous genetic backgrounds, are of host origin, and are due to spontaneous rather than engineered mutations. We found that intratumoral injection of C. novyi-NT spores was well tolerated in companion dogs bearing spontaneous solid tumors, with the most common toxicities being the expected symptoms associated with bacterial infections. Objective responses were observed in 6 of 16 dogs (37.5%), with three complete and three partial responses. On the basis of these encouraging results, we treated a human patient who had an advanced leiomyosarcoma with an intratumoral injection of C. novyi-NT spores. This treatment reduced the tumor within and surrounding the bone. Together, these results show that C. novyi-NT can precisely eradicate neoplastic tissues and suggest that further clinical trials of this agent in selected patients are warranted.

"Advances in the surgical management of bone tumors"

Bone tumor surgery is extremely challenging, particularly when tumors are located in tightly confined anatomical areas and abutting critical organs and neurovascular structures. Tumor resection requires good cutting accuracy to ensure safety, to achieve negative margins, and to preserve critical structures when possible. The purpose of this paper was to review the literature on the surgical advances for bone tumor surgery published within the last year. The majority of literature identified focused on computer-assisted surgical approaches. There is increasing evidence that 3D navigation plays an important role in the resection of bone tumors. Reconstruction materials that encourage healing and prevent infections are also in development. Optimal care includes execution of a well-developed pre-operative plan using a multidisciplinary approach led by the orthopaedic oncologist.

Enchondroma with secondary aneurysmal bone cyst

An enchondroma with complex cystic changes of the proximal femur is described in a 13-year-old male. The case illustrates a unique presentation of an enchondroma and reinforces the importance of considering the presence of secondary aneurysmal bone cysts in both benign and malignant lesions of bone.

Increased severity of glomerulonephritis in C-C chemokine receptor 2 knockout mice

Increased severity of glomerulonephritis in C-C chemokine receptor 2 knockout mice.

BACKGROUND

The C-C chemokine receptor 2 (CCR2) is expressed on monocytes and facilitates monocyte migration. CCR2 is a prominent receptor for monocyte chemoattractant protein-1 (MCP-1). This chemokine recruits monocytes to sites of inflammation. It has been suggested that CCR2 and its ligand, MCP-1, play a role in the pathogenesis of glomerulonephritis. The goal of this study was to determine the contribution of CCR2 in a murine model of accelerated nephrotoxic nephritis. We measured the extent of development of renal disease in CCR2 wild-type and knockout mice after the administration of antiglomerular basement membrane antibody.

METHODS

Eight groups of animals were treated (N = 10 per group). Four days after IgG immunization, CCR2 wild-type and knockout mice received control serum or nephrotoxic serum. The urinary protein/creatinine ratio was measured on days 1 and 3; plasma and kidneys were collected on days 4 and 7. Kidneys were evaluated by light microscopy, immunohistochemistry, and immunofluorescence. The genotype of mice was confirmed by tissue analysis.

RESULTS

Protective effects of CCR2 knockout on the urinary protein/creatinine ratio were observed on day 1, as values for this parameter were significantly lower (35 +/- 3.6) than in nephritic wild-type mice (50 +/- 6.8). There was a marked increase in proteinuria in nephritic wild-type mice on day 1 compared with vehicle-treated, wild-type animals (5 +/- 1.0). On day 3, the ameliorative effects of CCR2 knockout were not observed; the increase in the urinary protein/creatinine ratio was similar in nephritic CCR2 wild-type (92 +/- 11.2) and knockout mice (102 +/- 9. 2). Plasma markers of disease were evaluated on days 4 and 7. At these time points, there were no beneficial effects of CCR2 receptor knockout on plasma levels of urea nitrogen, creatinine, albumin, or cholesterol. On day 7, blood urea nitrogen (248 +/- 19.9 mg/dL) and plasma cholesterol were higher in nephritic CCR2 knockout mice than in wild-type mice (142 +/- 41.7 mg/dL) that received nephrotoxic serum. Histopathologic injury was more severe in nephritic CCR2 knockout mice than nephritic wild-type mice on day 4 (3.1 +/- 0.3 vs. 2.0 +/- 0.3) and day 7 (3.6 +/- 0.2 vs. 2.9 +/- 0.3). By immunohistochemical analysis at day 4, there were significantly fewer mac-2-positive cells, representative of macrophages in the glomeruli of nephritic CCR2 knockout (2.1 +/- 0.6) mice than nephritic wild-type (3.9 +/- 0.5) animals. By indirect immunofluorescence, there was a moderate, diffuse linear IgG deposition of equivalent severity present in glomeruli of both wild-type and CCR2 knockout nephritic mice.

CONCLUSION

These results suggest that our strategy was successful in reducing macrophage infiltration, but this model of glomerulonephritis is not solely dependent on the presence of CCR2 for progression of disease. After a transient ameliorative effect on proteinuria, CCR2 knockout led to more severe injury in nephritic mice. This raises the intriguing possibility that a CCR2 gene product ameliorates glomerulonephritis in this murine model. Although effects that occur in chemokine knockout mice are not equivalent to those expected with prolonged use of a chemokine antagonist, this study may nevertheless have implications for consideration of long-term use of chemokine antagonists in renal disease.

Captopril prevents nephropathy in HIV-transgenic mice

Transgenic mice (T26) bearing the envelope, regulatory, and accessory genes of HIV- I develop renal disease resembling human HIV-associated nephropathy (HIVAN). Effects of vehicle (VEH) and the angiotensin-converting enzyme inhibitor captopril (CAP) were examined in wild-type (WT) or T26 mice treated from 7 to 100 d of age. Mortality was lower in CAP T26 mice (30 mg/kg: 8%; 100 mg/kg: 12%) than VEH T26 mice (52%). The urinary protein/creatinine ratio was increased in VEH T26 mice (19.5+/-7.60) versus WT mice (6.1+/-0.83), but not in low-dose (7.3+/-0.94) or high-dose (8.2+/-1.02) CAP T26 mice. Blood urea nitrogen was higher in VEH T26 mice (52+/-16.2 mg/dl) than VEH WT mice (24+/-0.8). Blood urea nitrogen was also elevated in CAP WT (high dose: 43+/-2.1 mg/dl) and T26 mice (high dose: 42+/-2.4 mg/dl). Glomerular injury was higher in VEH T26 mice (6.8+/-0.58) than VEH WT mice (0.2+/-0.08) or CAP T26 mice (low dose: 1.1+/-0.17; high dose: 0.7+/-0.13). Tubulointerstitial injury was also greater in VEH T26 mice (1.1+/-0.10) than VEH WT mice (0.2+/-0.08) or CAP T26 mice (low dose: 0.4+/-0.10; high dose: 0.3+/-0.10). These data validate recent nonrandomized studies of captopril in HIV-infected patients, and suggest that an angiotensin-converting enzyme substrate is an important mediator in HIVAN. A randomized placebo-controlled trial of captopril in HIVAN may be warranted.

Cardiovascular and renal effects of endothelin B receptor selective agonists in spontaneously hypertensive rats

Renal effects of endothelin (ET)-3 have been described in normotensive but not spontaneously hypertensive rats (SHR). Infusion (170 ng/kg/min) of the ETB receptor selective agonists ET-3 and sarafotoxin S6c (SS6c) was used to investigate ETB receptor modulation of renal function in SHR. ET-3 decreased glomerular filtration rate (GFR) and renal plasma flow (RPF) by approximately 95% (0.1 +/- 0.01 and 0.1 +/- 0.02 ml/min, respectively) versus vehicle (1.3 +/- 0.08 and 3.6 +/- 0.23, respectively) in SHR. ET-3 exerted a biphasic effect on urine flow (UV); an initial increase and then a decrease (vehicle, 4.2 +/- 0.55; ET-3, 0.2 +/- 0.09 microliter/min). ET-3 increased mean arterial pressure (vehicle, 159 +/- 4.1; ET-3, 174 +/- 3.1 mm Hg). SS6c decreased GFR and RPF by approximately 60% (0.8 +/- 0.12 and 2.0 +/- 0.18 ml/min, respectively) versus vehicle (2.0 +/- 0.19 and 5.2 +/- 0.45, respectively). UV did not change. Depressor effects of SS6c were observed (vehicle, 154 +/- 1.5; SS6c, 127 +/- 3.1 mm Hg). The ETB receptor selective agonists ET-3 and SS6c markedly decreased GFR and RPF in SHR, suggesting that endogenous ET-3 may modulate renal function through ETB receptors in SHR.

Effects of endothelin in radiocontrast-induced nephropathy in rats are mediated through endothelin-A receptors

A role for endothelin in the pathogenesis of radiocontrast-induced nephropathy has been suggested by several studies, but the specific contributions of endothelin-A and endothelin-B receptors to the changes in renal function induced by endothelin in this form of renal failure have not been defined. This study examined the effects of the nonselective endothelin receptor antagonist SB-209,670, and the less potent, but selective, endothelin-A receptor antagonist BMS-182,874 in radiocontrast-induced nephropathy in rats. The doses used in this study were chosen from pressor testing data. BMS-182,874 (100 mumol/kg, iv) and SB-209,670 (30 mumol/kg, iv) maximally inhibited the endothelin-1-induced pressor response in rats. BMS-182,874 had no effect on the endothelin-B-mediated depressor response, whereas SB-209,670 abolished it. These results suggest that this is an endothelin-A selective dose of BMS-182,874, and an endothelin-A/B inhibitory dose of SB-209,670. Radiocontrast-induced nephropathy was produced in anesthetized rats (N = 6/group) by intravenous injection of indomethacin (5.0 mg/kg), the nitric oxide synthesis inhibitor N-nitro-L-arginine methyl ester (10.0 mg/kg), vehicle or antagonist, and the radiocontrast agent lopamidol (2,9 g iodine/kg). GFR was partially protected (P < 0.05) by BMS-182,874 (-43 +/- 3.0% change from baseline) compared with vehicle (-65 +/- 6.0%). The decrease in GFR in SB-209,670-treated rats that received lopamidol was intermediate between the other two groups. The fall in RPF induced by lopamidol was unchanged by either antagonist. The marked diuresis in lopamidol treated rats (630 +/- 125.1%) was reduced (P < 0.01) by BMS-182,874 (176 +/- 77.1%) or SB-209,670 (173 +/- 60.1%). Kidneys were collected for histopathologic evaluation approximately 1 h after lopamidol administration, and the percentage of medullary tubular ascending limbs (mTAL) with morphologic features of necrosis were enumerated by semiquantitative analysis. The percentage of mTAL necrosis was significantly decreased in the BMS-182,874- or SB-209,670-treated rats (P < 0.01) compared with vehicle plus lopamidol-treated animals. In summary, endothelin-A receptor blockade with a highly selective, well-characterized endothelin-A receptor antagonist partly protected GFR, and reduced the marked diuresis and mTAL necrosis in radiocontrast-induced nephropathy in rats. Administration of a nonselective endothelin receptor antagonist provided essentially equivalent ameliorative effects in this model, suggesting that blockade of endothelin-B receptors did not yield any additional protection. These results are consistent with the hypothesis that endothelin-A receptors mediate endothelin-induced changes in renal function and structure in this acute model of radiocontrast-induced nephropathy.

Dual metalloprotease inhibitors. 6. Incorporation of bicyclic and substituted monocyclic azepinones as dipeptide surrogates in angiotensin-converting enzyme/neutral endopeptidase inhibitors

A series of substituted monocyclic and bicyclic azepinones were incorporated as dipeptide surrogates in mercaptoacetyl dipeptides with the desire to generate a single compound which would potently inhibit both angiotensin-converting enzyme (ACE) and neutral endopeptidase (NEP). Many of these compounds displayed excellent potency against both enzymes. Two of the most potent compounds, monocyclic azepinone 2n and bicyclic azepinone 3q, demonstrated a high level of activity versus ACE and NEP both in vitro and in vivo.

A role for endothelin ETA receptors in regulation of renal function in spontaneously hypertensive rats

While there is evidence to suggest that endothelin-1 is involved in regulation of kidney function and blood pressure, the importance of endothelin ETA receptors in this area has not been clearly defined. The novel, non-peptide endothelin ETA receptor antagonist, BMS-182874, (5-(dimethylamino)-N-(3,4- dimethyl-5-isoxazolyl)-1-naphthalene sulfonamide) was used to examine effects of endothelin ETA receptor blockade on renal function in spontaneously hypertensive rats. Preliminary studies were conducted to determine an effective dose of BMS-182874. Infusion of BMS-182874 (10 mumol/kg/min, i.v.) inhibited effects of exogenous endothelin-1 on glomerular filtration rate, renal blood flow, and mean arterial pressure in Sprague-Dawley rats. Administration of BMS-182874 (10 mumol/kg/min, i.v.) to anesthetized, male, spontaneously hypertensive rats decreased renal blood flow by approximately 50% (1.2 +/- 0.11 ml/min/100 g body weight) compared to vehicle (2.7 +/- 0.23). There was no effect of BMS-182874 on glomerular filtration rate (0.5 +/- 0.05 ml/min/100 g body weight; vehicle: 0.7 +/- 0.06). Mean arterial pressure decreased significantly after BMS-182874 (123 +/- 3.8 mm Hg; vehicle: 162 +/- 4.8). Urine flow and renal vascular resistance were unchanged by BMS-182874. Endothelin ETA receptor density was increased approximately 50% in spontaneously hypertensive rat kidneys compared to normotensive kidneys, with no change in equilibrium dissociation constant. Endothelin ETB receptor density and equilibrium dissociation constant were similar in the two rat strains. Plasma immunoreactive endothelin was higher in hypertensive (5.9 +/- 0.31 fmol/ml) than normotensive rats (2.8 +/- 0.15). The results suggest endothelin ETA receptors may play a role in the regulation of renal function in this model of hypertension.

Cardiovascular effects of the novel dual inhibitor of neutral endopeptidase and angiotensin-converting enzyme BMS-182657 in experimental hypertension and heart failure

Combined neutral endopeptidase (NEP) and angiotensin-converting enzyme (ACE) inhibition produces greater acute hemodynamic effects than either treatment alone. We investigated whether BMS-182657 (BMS), which bears inhibitory activities against both NEP and ACE, elicited similar enhanced effects. BMS inhibited NEP and ACE, in vitro (IC50 = 6 and 12 nM, respectively) and the pressor response to Ang I in rats. In deoxycorticosterone acetate (DOCA)-salt hypertensive rats sensitive to NEP inhibition but not to ACE inhibition, BMS at 100 mumol/kg i.v. lowered mean arterial pressure (MAP) from 180 +/- 6 to 151 +/- 5 mm Hg. In sodium-depleted, spontaneously hypertensive rats (SHR) sensitive to ACE inhibition but not to NEP inhibition, BMS at 100 mumol/kg p.o. lowered MAP from 151 +/- 4 to 123 +/- 5 mm Hg. Cardiomyopathic hamsters with heart failure were administered vehicle or one of the following (30 mumol/kg i.v.): the ACE inhibitor enalaprilat; the NEP inhibitor SQ-28603; or BMS. Enalaprilat and SQ-28603 had minimal hemodynamic effects. BMS decreased left ventricular end-diastolic pressure by 12 +/- 2 and 10 +/- 1 mm Hg and left ventricular systolic pressure by 27 +/- 2 and 23 +/- 3 mm Hg at 30 and 60 min, respectively (P < .05 vs. each other group). These changes were associated with a 40% increase in cardiac output, a 47% decrease in peripheral vascular resistance and a lowering of MAP by 21 +/- 3 mm Hg at 60 min (P < .05 vs. each other group). There were no significant differences in the changes in heart rate or left ventricular stroke work index among the four groups. Hence, BMS-182657 is a dual inhibitor of NEP and ACE, is antihypertensive irrespective of the activity of the renin-angiotensin system and has acute hemodynamic effects in hamsters with heart failure greater than those produced by selective inhibition of NEP or ACE. The NEP and ACE inhibitory activities of BMS-182657 act synergistically and mimic the interaction resulting from combining selective inhibitors of these enzymes.

Antihypertensive effects of a novel endothelin-A receptor antagonist in rats

Endothelin is a potent pressor agent mediated primarily through activation of endothelin-A receptors on vascular smooth muscle. Surprisingly, there is no consensus in the literature regarding the role of endothelin itself or endothelin-A receptors in hypertension. The goal of this study was to compare the effects of the novel, selective endothelin-A receptor antagonist BMS-182874 in various models of hypertension. BMS-182874 specifically inhibited the pressor response to endothelin-1 (0.3 nmol/kg IV) in Sprague-Dawley rats in a dose-dependent manner (ED25 = 8 mumol/kg IV) but had no effect on changes in mean arterial pressure brought about by other vasoactive agents. The antihypertensive effects of BMS-182874 were evaluated in conscious deoxycorticosterone acetate (DOCA)--salt hypertensive rats, spontaneously hypertensive rats (SHR), and sodium-deplete SHR. BMS-182874 reduced blood pressure in DOCA--salt hypertensive rats when administered at a dose of 30, 100, or 300 mumol/kg IV. A maximal decrease of approximately 45 mm Hg was observed after treatment with 100 mumol/kg IV. Three days of oral or intravenous treatment with BMS-182874 (100 mumol/kg) elicited a sustained decrease in blood pressure in the DOCA--salt hypertensive rats. In SHR, BMS-182874 decreased blood pressure by approximately 30 mm Hg, but the antihypertensive effects were similar at doses of 75, 150, and 450 mumol/kg PO. In sodium-deplete SHR, BMS-182874 did not significantly reduce blood pressure. In summary, BMS-182874 is a specific, orally active endothelin-A receptor antagonist that is efficacious in mineralocorticoid hypertension in rats but has less effect in sodium-replete and sodium-deplete SHR.(ABSTRACT TRUNCATED AT 250 WORDS)

BMS-182874 is a selective, nonpeptide endothelin ETA receptor antagonist

BMS-182874 [5-(dimethylamino)-N-(3,4-dimethyl-5-isoxazolyl)-1-naphthalene sulfonamide] is a recently discovered, low molecular weight, nonpeptide endothelin (ET) receptor antagonist. BMS-182874 competitively inhibited the binding of [125I]ET-1 to ETA receptors in rat vascular smooth muscle A10 (VSM-A10) cell membranes (Ki = 61 nM) and in CHO cells stably expressing the human ETA receptor (Ki = 48 nM), but was a weak inhibitor at ETB receptors (Ki > 50 microM) and non-ET receptors. BMS-182874 inhibited ET-1-stimulated inositol phosphate accumulation (KB = 75 nM) and calcium mobilization (KB = 140 nM) without suppressing the maximal responses in VSM-A10 cells. BMS-182874 was a competitive antagonist of force development elicited by stimulation of ETA, but not other, receptors in isolated blood vessels such as the rabbit carotid artery (KB = 520 nM). The apparent discrepancy between efficacy in cell and tissue models was likely related to the high degree of protein binding exhibited by BMS-182874. When administered either orally (ED50 = 30 mumol/kg) or intravenously (ED50 = 24 mumol/kg) to conscious, normotensive rats, BMS-182874 blunted the pressor response to exogenous ET-1. These data demonstrate that BMS-182874 is a competitive, selective and orally active ETA receptor antagonist that will be useful in understanding the role of ET in normal and disease states.

Endogenous synthesis of endothelin-1 may mediate a delayed pressor response after injection of endothelin-1 in rats

We previously described delayed pressor response (DPR) 3 h after endothelin (ET)-1 injection in normotensive rats. In the current study, we examined effects of the ETA receptor antagonist BQ123 (0.01 mumol/kg/min intravenously, i.v.), phosphoramidon (100 mumol/kg i.v.), the neutral endopeptidase inhibitor SQ28603 (112 mumol/kg + 0.04 mumol/kg/min i.v.), the angiotensin-converting enzyme inhibitor enalaprilat (10 mumol/kg i.v.), and the thromboxane receptor antagonist, SQ29548 (0.5 mumol/kg + 0.5 mumol/kg/h i.v.) on DPR. Vehicle and ET-1 (1.0 nmol/kg i.v.) were administered on day 1; vehicle or drug and ET-1 were administered on day 2. BQ123 inhibited DPR 36% (vehicle 44 +/- 5, BQ123 28 +/- 3 mm Hg); phosphoramidon inhibited DPR 56% (vehicle 45 +/- 4, and phosphoramidon 20 +/- 5 mm Hg). DPR was unchanged after SQ28603 (vehicle 39 +/- 2 and SQ28603 44 +/- 2 mm Hg), enalaprilat (vehicle 39 +/- 2 and enalaprilat 38 +/- 7 mm Hg), or SQ29548 (vehicle 46 +/- 6 and SQ29548 43 +/- 3 mm Hg). The results suggest that DPR 3 h after ET-1 injection in rats is mediated in part through ETA receptors. DPR does not appear to involve thromboxane or synthesis of angiotensin II (AII), but may be related to synthesis of ET-1.

Comparison of a novel ETA receptor antagonist and phosphoramidon in renal ischemia

Infusion (0.46 mumol/kg/min) of the endothelin (ET)-converting-enzyme inhibitor, phosphoramidon (P), protected function and structure after 30 min renal ischemia in rats more than treatment (5 mumol/kg/min) with the ETA receptor antagonist, BMS-182874 (B). The glomerular filtration rate (GFR; 0.7 +/- 0.12 ml/min) and renal plasma flow (RPF) decreased approximately 40% at 2 h reflow versus controls (C: 1.2 +/- 0.12). B weakly protected the GFR (0.8 +/- 0.07 ml/min); P restored it (1.1 +/- 0.05). Both compounds reduced tubular injury at 2 h reflow; P ameliorated glomerular changes. At 24 h the GFR (0.6 +/- 0.06 ml/min) and RPF decreased 67% versus C (1.8 +/- 0.08). B did not protect the GFR and RPF. P partially protected the GFR (0.9 +/- 0.07 ml/min) but not RPF, and reduced tubular injury. The results suggest that both ETA and non-ETA receptors mediate ET-induced changes in ischemic renal failure.

Incomplete inhibition of endothelin-1 pressor effects by an endothelin ETA receptor antagonist

Incomplete inhibition of endothelin-1-induced pressor effects by FR-139317, a novel, potent, ETA receptor antagonist, was observed in conscious, normotensive rats. Maximum inhibition by FR-139317 of the endothelin-1 pressor response (0.1, 0.3, 1.0 nmol/kg) was 49 +/- 7, 41 +/- 3, 62 +/- 5%, respectively. Two ETB-selective receptor ligands induced pressor responses in conscious rats. A portion of the endothelin-1 pressor response may be mediated by ETB receptors, and ETB-mediated vasoconstriction may contribute to incomplete inhibition of the pressor response to endothelin-1 by an ETA-selective receptor antagonist.

Quinoxaline N-oxide containing potent angiotensin II receptor antagonists: synthesis, biological properties, and structure-activity relationships

A series of novel quinoxaline heterocycle containing angiotensin II receptor antagonist analogs were prepared. This heterocycle was coupled to the biphenyl moiety via an oxygen atom linker instead of a carbon atom. Many of these analogs exhibit very potent activity and long duration of effect. Interestingly, the N-oxide quinoxaline analog was more potent than the nonoxidized quinoxaline as in the comparison of compounds 5 vs 30. In order to improve oral activity, the carboxylic acid function of these compounds was converted to the double ester. This change did result in an improvement in oral activity as represented by compound 44.

Effects of the endothelin (ET) receptor antagonist BQ 123 on initial and delayed vascular responses induced by ET-1 in conscious, normotensive rats

The ETA receptor antagonist, BQ 123 was used to characterize depressor and initial and delayed pressor responses to ET-1 in conscious rats. BQ 123 (0.001-0.01 mumol/kg/min) dose-dependently inhibited the initial ET-1 (0.1 nmol/kg) pressor response, reaching a maximum after 0.01 BQ 123 (61 +/- 4% inhibition). Less inhibition of the pressor effects occurred after higher doses of BQ 123 (1: 10 +/- 6% inhibition). The depressor response to 1 nmol/kg ET-1 was unchanged by BQ 123 (0.01), but inhibited by BQ 123 (1). The initial pressor response to 1.0 nmol/kg ET-1 was inhibited by BQ 123 (0.01: 26 +/- 6%; 1.0: 41 +/- 3% inhibition). The delayed pressor response, 180 min post-ET-1 (+41 +/- 2% increase) was reduced by BQ 123 infused before the delayed peak (+14 +/- 5% increase). Plasma immunoreactive ET values were: control: 5.4 +/- 0.4; initial peak: 491.4 +/- 50.6; delayed peak: 8.2 +/- 0.6 fmol/ml. The delayed ET-1 response does not coincide with sustained high circulating levels of immunoreactive ET, but inhibition of the response by BQ 123 suggests that it may involve endothelin receptors.

Dihydropyrimidine angiotensin II receptor antagonists

The discovery of the nonpeptide angiotensin II (AII) receptor antagonist losartan, previously called DuP 753, has stimulated considerable interest in the synthesis of novel analogs of this compound. Our efforts in this area have resulted in the discovery of dihydropyrimidines as potent AII receptor antagonists. The chemistry leading to this novel class of AII antagonists and their biological properties are reported in this publication. Structure-activity studies showed that a variety of substituents are tolerated on the dihydropyrimidine ring, indicating that the AII receptor is permissive in accepting this region of the nonpeptide antagonists. As reported for imidazole-based AII antagonists, the tetrazolyl dihydropyrimidine analogs were found to be more potent than the corresponding carboxylic acids. Our studies show that dihydropyrimidine analogs 2-butyl-4-chloro-1,6-dihydro-6-methyl-1-[[2'-(1H-tetrazol-5-yl)[1, 1'-biphenyl]-4-yl]methyl]pyrimidine-5-carboxylic acid, ethyl ester (Ki = 8.3 nM), 2-butyl-4-chloro-1,6-dihydro-6-methyl-1- [[2'-(1H-tetrazol-5-yl)[1,1'-biphenyl]-4-yl]methyl]-5- pyrimidinecarboxylic acid (Ki = 1.0 nM), and 2-butyl-6-chloro-1,4-dihydro-4,4-dimethyl-1-[[2'-(1H-tetrazol-5-yl )[1,1'- biphenyl]-4-yl]methyl]-5-pyrimidinecarboxylic acid, ethyl ester (Ki = 1.1 nM), display affinities for the AII receptor which are comparable to or better than losartan (Ki = 9.0 nM). One of these derivatives, 2-butyl-4-chloro-1,6-dihydro-6-methyl-1-[[2'-(1H-tetrazol-5- yl)[1,1'-biphenyl]-4-yl]methyl]pyrimidine-5-carboxylic acid, ethyl ester, showed antihypertensive activity on oral administration to spontaneously hypertensive rats. These results demonstrate that the imidazole of losartan can be successfully replaced with a dihydropyrimidine ring.