Preoperative Stereotactic Body Radiation Therapy for Soft-Tissue Sarcoma: Results of Phase 2 Study.

Purpose: Preoperative radiation followed by surgical resection is a standard treatment for soft-tissue sarcomas (STS). We report on 2 consecutive, phase 2, single-arm studies evaluating 5 fraction stereotactic body radiation therapy (SBRT) treatments followed by surgical resection for STS (clinical trails.gov NCT02706171). Methods and Materials: A total of 16 patients were treated with preoperative SBRT. Tumor size in the greatest dimension was a median 6.7 cm (maximum: 14 cm) and the majority of STS were in the extremities. SBRT consisted of 35 to 40 Gy in 5 fractions every other day. Results: Median follow-up time was 1719 days (4.7 years). Grade ≥3 acute toxicity occurred in 1 patient (grade 3 skin changes). Fifteen patients proceeded with surgical resection. Three patients had a wound complication after surgery, 1 patient had grade ≥3 late toxicity (grade 4 requiring surgical intervention). There was 1 local recurrence and 5 distant recurrences. Conclusions: Long-term follow-up on SBRT for STS found acceptable control and toxicity rates, and warrants further evaluation.

Induction of Myogenic Differentiation Improves Chemosensitivity of Chemoresistant Cells in Soft-Tissue Sarcoma Cell Lines.

Rhabdomyosarcoma (RMS) and rhabdoid tumors (RT) are rare soft-tissue malignancies with the highest incidence in infants, children, and adolescents. Advanced, recurrent, and/or metastatic RMS and RT exhibit poor response to treatment. One of the main mechanisms behind resistance to treatment is believed to be intratumoral heterogeneity. In this study, we investigated the myogenic determination factor 1 (MYOD1) and Noggin (NOG) markers in an embryonal RMS (ERMS) cell line and an RT cell line and the differential response of the MYOD1 and NOG expressing subpopulations to chemotherapy. Importantly, we found that these markers together identify a subpopulation of cells (MYOD1+ NOG+ cells) with primary resistance to Vincristine and Doxorubicin, two commonly used chemotherapies for ERMS and RT. The chemoresistant MYOD1+ NOG+ cells express markers of undifferentiated cells such as myogenin and ID1. Combination of Vincristine with TPA/GSK126, a drug combination shown to induce differentiation of RMS cell lines, is able to partially overcome MYOD1/NOG cells chemoresistance.

Rhabdomyosarcoma and Wilms tumors contain a subpopulation of noggin producing, myogenic cells immunoreactive for lens beaded filament proteins.

Myo/Nog cells are identified by their expression of the skeletal muscle specific transcription factor MyoD and the bone morphogenetic protein inhibitor noggin, and binding of the G8 monoclonal antibody. Their release of noggin is critical for morphogenesis and skeletal myogenesis. In the adult, Myo/Nog cells are present in normal tissues, wounds and skin tumors. Myo/Nog cells in the lens give rise to myofibroblasts that synthesize skeletal muscle proteins. The purpose of this study was to screen human lens tissue, rhabdomyosarcoma cell lines, and tissue sections from rhabdomyosarcoma, Wilms and tumors lacking features of skeletal muscle for co-localization of antibodies to Myo/Nog cell markers and the lens beaded filament proteins filensin and CP49. Immunofluorescence localization experiments revealed that Myo/Nog cells of the lens bind antibodies to beaded filament proteins. Co-localization of antibodies to G8, noggin, filensin and CP49 was observed in most RC13 and a subpopulation of RD human rhabdomyosarcoma cell lines. Western blotting with beaded filament antibodies revealed bands of similar molecular weights in RC13 and murine lens cells. Human alveolar, embryonal, pleomorphic and spindle cell rhabdomyosarcomas and Wilms tumors contained a subpopulation of cells immunoreactive for G8, noggin, MyoD and beaded filaments. G8 was also co-localized with filensin mRNA. Staining for beaded filament proteins was not detected in G8 positive cells in leiomyosarcomas, squamous and basal cell carcinomas, syringocarciomas and malignant melanomas. Lens beaded filament proteins were thought to be present only in the lens. Myo/Nog-like cells immunoreactive for beaded filaments may be diagnostic of tumors related to the skeletal muscle lineage.

The measurement of physical functioning among patients with Tenosynovial Giant Cell Tumor (TGCT) using the Patient-Reported Outcomes Measurement Information System (PROMIS).

BACKGROUND: Tenosynovial giant cell tumor (TGCT), a rare, locally aggressive neoplasm of the synovium of joints and tendon sheaths, is associated with joint destruction, pain and swelling. Impacts on physical function (PF) vary depending on tumor size and location. The aim of this study was to identify relevant items, and demonstrate the content validity of custom measures of lower extremity PF from the Patient-Reported Outcomes Measurement Information System Physical Function Physical Function (PROMIS-PF) item bank among patients with TGCT. METHODS: Patients were recruited for qualitative research interviews to identify predominant TGCT symptoms and impacts. Patients completed a checklist to evaluate the relevance of each PROMIS-PF item. The publicly available PROMIS-PF item response theory (IRT) parameters were used to select items representing the range of the latent PF trait. RESULTS: Participants (n = 20) were 75% female, mean age 42.5 years. TGCTs were located in the knee (n = 15), hip (n = 3), and ankle (n = 2). Fifty-four PROMIS-PF items were identified as relevant by ≥20% of the participants. PF concepts discussed by participants during the qualitative interviews were also used to select relevant items. Selected items (n = 13) were used to create a physical function subscale specific to lower extremity tumors. CONCLUSIONS: We describe a novel method of combining qualitative research and IRT-based item information to select a relevant and content valid subset of PROMIS-PF items to assess heterogeneous impacts on PF in TGCT, a rare disease population.

Multidisciplinary Approach to Treatment of Soft Tissue Sarcomas Requiring Complex Oncologic Resections.

BACKGROUND: To review the experience and outcome of utilizing a multidisciplinary team, including vascular surgery and orthopedic surgery, in the operative treatment of soft tissue sarcomas (STSs) at an academic, tertiary care hospital. METHODS: A retrospective review was performed of all patients who underwent elective STS resection between July 1, 2012 and January 31, 2015, since the addition of a specialized cancer treatment center and a dedicated oncologic division of orthopedic surgery. Surgical cases performed in conjunction with both orthopedic and vascular surgery were reviewed. RESULTS: Sixty-three patients underwent 66 surgical resections for STS during the study period. There were no perioperative deaths. Fifty-two lower-extremity resections (78.8%), 6 upper-extremity resections (9.1%), and 8 pelvic resections (12.1%) were performed. Sixteen cases required a vascular intervention (24.2%). These interventions included bypass in 2 patients (12.5%), primary repair of a named vessel in 4 patients (25%), and ligation of a named vessel in 10 patients (62.5%). Three patients had local recurrence of their tumor (4.5%), requiring further resection during the follow-up period. Seven patients required a primary amputation (10.6%). The average size of the tumor removed was 1,776 mL, ranging from 5 mL to 36,300 mL. CONCLUSIONS: The quality of surgical resection is paramount in optimal treatment of STS; however, wide resection of STS can result in prolonged operative times, significant blood loss, vascular complications, and functional deficits. A multidisciplinary surgical team including orthopedic and vascular teams may improve the treatment by optimizing complex resections that may require involved vascular control or reconstruction.

Preoperative Radiosurgery for Soft Tissue Sarcoma.

OBJECTIVES: Preoperative radiation followed by surgical resection is a standard treatment for soft tissue sarcomas (STSs). The conventional method of radiation is 5 weeks to approximately 50 Gy. We report on our initial experience and phase II single-arm study assessing 5 fractions of stereotactic body radiotherapy (SBRT), followed by surgical resection for STS. METHODS: Thirteen patients and 14 tumors were treated with preoperative SBRT; tumors were mostly poorly differentiated (5) or myxoid (5) and were located on the leg (10), arm (2) or groin (2). The median tumor size in greatest dimension was 7.6 cm (maximum 16 cm). Twelve patients received 35 Gy in 5 fractions; for 2 deeper tumors the dose was 40 Gy in 5 fractions. Ten patients were administered 0.5 cm bolus to improve the dose. Gross tumor volume was expanded 0.5 cm radially and 3 cm along the tissue plane. Treatment was to an isodose line (median 81%) and was delivered every other day. Maximum dose to the skin was 46 Gy (median 41 Gy). RESULTS: The median follow-up period was 279 days. Surgical resection occurred a median of 37 days after completion of SBRT. Four patients had acute toxicity consisting of 2 grade 2 and 2 grade 3 skin reactions; all cases of skin toxicity resolved by the time of surgery. Percent tumor necrosis ranged from 10% to 95% (median 60%). All patients had negative margins. Planned vacuum-assisted wound closure was used in 4 patients; there were no other major wound complications. There was 1 local recurrence and 7 distant recurrences. CONCLUSION: This is the initial experience of radiosurgery for preoperative treatment of STSs. We have found this to be well tolerated, convenient for the patients, and a much shorter treatment course, allowing patients to undergo surgery and subsequent chemotherapy quicker. Surgical complications and control rates are satisfactory. The initial results are encouraging for further investigation.

Aspirin for Prophylaxis Against Venous Thromboembolism After Orthopaedic Oncologic Surgery.

BACKGROUND: Patients who undergo orthopaedic oncologic surgical procedures are at increased risk of developing a venous thromboembolism (VTE). Guidelines from surgical societies are shifting to include aspirin as a postoperative VTE prophylactic agent. The purpose of this study was to review our experience using aspirin as postoperative VTE prophylaxis for orthopaedic oncologic surgical procedures. METHODS: This study was a retrospective review of patients diagnosed with a primary malignant soft-tissue or bone tumor or metastatic carcinoma. Demographic information, histopathologic diagnosis, VTE history, surgical procedure, and VTE prophylaxis were analyzed. VTE rates in the overall and prophylactic-specific cohorts were recorded and compared. RESULTS: A total of 142 distinct surgical procedures in 130 patients were included. VTE prophylaxis with aspirin was used after 103 procedures, and non-aspirin prophylaxis was used after 39. In 33 cases, imaging was used to investigate for VTE because of clinical signs and symptoms. VTE developed after 7 (4.9%) of the 142 procedures. There were 6 deep venous thromboses (DVTs) and 1 pulmonary embolism, and 2 of the VTEs presented in patients with a VTE history. VTE developed in 2.9% (3) of the 103 aspirin cases and 10.3% (4) of the 39 non-aspirin cases. No patient in the aspirin group who had been diagnosed with metastatic carcinoma, malignant soft-tissue sarcoma, lymphoma, or multiple myeloma developed a VTE. Risk factors for VTE development included diabetes mellitus (odds ratio [OR] = 10.40, 95% confidence interval [CI] = 1.61 to 67.30), a history of VTE (OR = 7.26, 95% CI = 1.19 to 44.25), postoperative transfusion (OR = 34.50, 95% CI = 3.94 to 302.01), and estimated blood losses of 250 mL (OR = 1.50, 95% CI = 1.11 to 2.03), 500 mL (OR = 2.26, 95% CI = 1.23 to 4.13), and 1,000 mL (OR = 5.10, 95% CI = 1.52 to 17.04). CONCLUSIONS: Aspirin may be a suitable and effective option for VTE chemoprophylaxis in patients treated with orthopaedic oncologic surgery, especially those diagnosed with a soft-tissue sarcoma. Research with a more advanced study design is required. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Measuring clinically relevant endpoints in a serum-free, three-dimensional, primary cell culture system of human osteoarthritic articular chondrocytes.

Osteoarthritis (OA) is characterized by degeneration of articular cartilage within the joint, inflammation and pain. The purpose of this study was to develop a primary, serum free cell culture system of human osteoarthritic articular chondrocytes (HOACs) with which to study manifestations of the disease process. Joint tissues were obtained from OA patients undergoing total knee arthroplasty (TKA). HOACs isolated from the femoral condyles and tibial plateau of the same side were combined, plated in three-dimensional, alginate beads and cultured for five days in serum, hormone and protein free medium. More living cells were obtained from the femoral condyles than the tibial plateau. The optimal plating density was 2.5 × 106 cells/ml of alginate. The amounts of DNA, RNA, proteoglycans and total collagen were similar in cultures prepared from the sides of least and greatest pathology. More type 1 than type 2 collagen was detected in the medium on days 2 and 5. A greater percentage of type 1 than type 2 collagen was degraded. The inflammatory cytokine interleukin-1 beta was present in the medium and alginate associated matrix. Although variation in the metabolic profiles between subjects was observed, HOACs from all patients continued to reflect the OA phenotype for five days in culture. This serum free, three-dimensional primary culture system of HOACs provides a platform with which to measure clinically relevant endpoints of OA and screen potential disease modifying OA therapeutics.

Novel case of Trevor's disease: Adult onset and later recurrence.

Dysplasia epiphysealis hemimelica (DEH), or Trevor's disease, is an osteocartilaginous epiphyseal overgrowth typically occurring in children. The literature reports 6 adult cases and none describe recurrence requiring additional procedures. We present a new-onset proximal tibial DEH in an adult recurring approximately 3 years after open excision. A 39-year-old female presented with a history of right knee pain, swelling, and instability. Physical examination revealed a firm proximal tibial mass. Computed tomography (CT) imaging showed an exophytic, lobulated, sclerotic mass involving the anterolateral margin of the lateral tibial plateau. Magnetic resonance imaging was suggestive of an osteochondroma. The patient underwent curettage of the lesion due to its periarticular location. Histology revealed benign and reactive bone and cartilage consistent with periosteal chondroma. Two and a half years later, the patient presented with a firm, palpable mass larger than the initial lesion. CT revealed a lateral tibial plateau sclerotic mass consistent with recurrent intra-articular DEH. A complete excision was performed and histology showed sclerotic bone with overlying cartilage consistent with exostosis. DEH is a rare epiphyseal osteocartilaginous outgrowth frequently occurring in the long bones of children less than 8 years old. DEH resembles an osteochondroma due to its pediatric presentation and similar histologic appearance. Adult-onset cases comprise less than 1% of reported cases. Recurrence rate after surgical intervention is unknown. Only 1 such case, occurring in a child, has been described. Clinicians contemplating operative treatment for DEH should note the potential for recurrence and consider complete excision. A follow-up period of several years may be warranted to identify recurrent lesions.

Pigmented Villonodular Synovitis: A Comprehensive Review and Proposed Treatment Algorithm.

Evidence now exists suggesting a neoplastic origin for pigmented villonodular synovitis, including a thorough description of the translocations involved. Arthroscopic excision for localized pigmented villonodular synovitis allows for both minimal recurrence and morbidity when compared with open excision; however, open excision still plays an important role in treating posterior compartment nodules. The optimal surgical treatment for diffuse pigmented villonodular synovitis is still a matter for debate, with combined anterior arthroscopic and open posterior excision being considered the preferred method. Radiation therapy has re-emerged as an additional treatment method for pigmented villonodular synovitis; however, the potential for serious toxicity makes it a questionable option, especially for such a benign condition. Small molecule and monoclonal antibody targeted therapies are being investigated as novel treatment methods for pigmented villonodular synovitis, with promising results.

Patient-reported Symptoms of Tenosynovial Giant Cell Tumors.

PURPOSE: Tenosynovial giant cell tumor (TGCT), a rare locally aggressive neoplasm of the synovium of joints and tendon sheaths, is associated with joint destruction, inflammation, pain, and swelling, in part due to colony-stimulating factor 1 receptor-bearing macrophages recruited to the tumor by genetic elevation of colony-stimulating factor 1 activity. The most common treatment is surgery, although promising pharmacologic treatments are in development. Patient-reported outcome (PRO) instruments are critical end points in demonstrating the clinical relevance of standard oncologic outcome measures and the overall impact of novel pharmacologic therapies in nonmalignant neoplastic conditions such as TGCT. The content validity of PROs relevant to patients with TGCT has not been formally investigated, and instruments to evaluate such outcomes do not exist for this condition. METHODS: PRO instruments of potential relevance were evaluated by using a literature review and by clinical and PRO experts. Patients with TGCT were recruited through clinical sites and the Internet for participation in qualitative research interviews to identify predominant symptoms and to test the relevance and content validity of several PRO measures. Select PRO measures were included in a Phase I clinical trial, and preliminary results of the PRO end points are reported descriptively. FINDINGS: Of the 22 subjects who participated in qualitative interviews, 73% were female, and their mean age was 42.5 years (range, 27-56 years). The TGCTs (19 diffuse and 3 localized) were located in the knee (n = 15), hip (n = 3), ankle (n = 2), elbow (n = 1), and forearm (n = 1). The most common symptoms cited were pain (82%), swelling (86%), stiffness (73%), reduced range of motion (64%), and joint instability (64%), which were consistent with clinical expert input and with the content of instruments chosen by PRO experts. The worst pain numeric rating scale, Patient Reported Outcomes Measurement Information System physical functioning items, and the Western Ontario and McMaster Universities Osteoarthritis Index, as well as a worst stiffness numeric rating scale developed for TGCT, were confirmed as meaningful measures of TGCT patient symptoms and were well understood in qualitative interviews. Results from the Phase I trial showed trends of improvement in both pain and stiffness over time. IMPLICATIONS: This study is the first to gather information directly from patients with TGCT regarding their symptom experiences. Pain, stiffness, and physical functioning are important treatment outcomes in patients with TGCT. We have identified content-valid PRO measures of these concepts, which are included in an ongoing Phase III TGCT clinical trial with pexidartinib (PLX3397) (NCT02371369).

A simplified approach to reconstruction of hemipelvectomy defects with lower extremity free fillet flaps to minimize ischemia time.

External hemipelvectomy associated with trauma or during the operative management of musculoskeletal sarcomas may yield a soft tissue defect that can only be sufficiently covered by free tissue transfers. The application of "spare-parts surgery," such as a fillet of leg or thigh flap, uses distal uninvolved parts that are otherwise viable tissues as donor tissues to cover defects. This concept has great utility to achieve soft tissue coverage in challenging cases, such as hemipelvectomy. However, during such complicated and time-consuming cases, prolonged ischemia time of the proposed donor tissues can be problematic. We describe a technique developed by the senior author (SJK) that minimizes the ischemia time of donor free tissues during external hemipelvectomy. This technique is applicable to other surgeries where filleted spare parts are the donor-site source for free tissue transfer.

Angiosarcoma Arising in Chronic Expanding Hematoma: Five Cases of an Underrecognized Association.

Little is known about the etiology or pathogenesis of angiosarcoma (AS). We describe a series of 5 cases of AS arising in chronic expanding hematomas. Inclusion criteria were the presence of a hematoma of at least 1-year duration and a thick fibrous wall surrounding the hematoma. Patients were 4 men and 1 woman; ages ranged from 43 to 71 years. Locations were the thigh (3), chest wall (1), and pelvic soft tissue involving the ischial bone (1). Hematoma duration ranged from 2 to 25 years. All cases had large cystic hematomas >10 cm; 2 had prior radiation. Thick fibrous walls surrounded the hematomas, with foci of hemosiderin and foamy histiocytes. Wall thickness ranged from 0.2 to 1.0 cm and varied within lesions. All AS were epithelioid, and in 3 cases the tumor invaded through the cyst wall. Immunoreactive nuclear c-myc was noted in 3/3 cases available for testing. Follow-up disclosed 4 patients developed metastatic disease, 3 of whom died of disease, 4, 8, and 15 months after diagnosis; the fourth patient is alive without disease after chemotherapy at 59 months. One patient without metastases is alive without disease 18 months after diagnosis; this tumor was confined to the cyst without penetration through the wall. We identified 4 similar cases in the literature, 3 as individual case reports (all epithelioid AS), and 1 as part of a series of AS. To our knowledge, this is the first series of AS arising in chronic expanding hematomas. Recognition of this unusual complication should alert clinicians to provide periodic clinical follow-up to these patients and to biopsy any case with sudden or uncontrolled enlargement. We recommend that excised chronic hematomas be well sampled histologically to search for AS and, if identified, to determine its extent and invasiveness.

Adult intramedullary ewing sarcoma of the proximal hip.

Ewing sarcoma of bone is classically a permeative lesion in the diaphysis of long bones in children. While they occur primarily in children and adolescents, they can be seen in young adults in their 20s, but these are typically seen in flat bones. The permeative nature of the lesion can elicit new bone formation creating a partially sclerotic appearance, cortical expansion presenting as a "Codman triangle," or have an "onion-skin" type of aggressive periosteal reaction/periostitis. Ewing sarcoma is rarely seen without an associated soft-tissue mass and is even rarer to just have benign-appearing periostitis (e.g., thick, uniform, or wavy cortex). We present such a case of Ewing sarcoma in a young adult confined to just the medullary metadiaphysis without cortical erosion or soft-tissue mass. To the best of our knowledge, this is the first case to be reported in the radiology literature.

Surgical management of metastatic long bone fractures: principles and techniques.

Management of metastatic long bone fractures requires identification of the lesion and the use of sound fracture fixation principles to relieve pain and restore function. The treating surgeon must understand the principles of pathologic fracture fixation before initiating treatment. Because these fractures occur in the context of a progressive systemic disease, management typically involves a multidisciplinary approach. When considering surgical stabilization of these fractures, the abnormal (or absent) healing environment associated with diseased bone and the overall condition of the patient must be taken into account. The goal of surgery is to obtain a rigid mechanical construct, which allows for early mobility and weight bearing. This can be achieved using internal fixation with polymethyl methacrylate cement or segmental resection and joint reconstruction. Prosthetic joint arthroplasty is a more reliable means of fracture management when insufficient bone is present for fixation. Prophylactic stabilization of impending pathologic fractures can reduce the morbidity associated with metastatic lesions.

Is a cancer diagnosis a teachable moment for the patient's relative who smokes?

PURPOSE: This study examined a cancer diagnosis, versus orthopedic surgery, as a teachable moment for recruiting smokers and treating nicotine dependence among patients' relatives. METHODS: Cancer patients and, for comparison, orthopedic patients at the University of Pennsylvania Health System were approached for referrals of relatives for a smoking cessation program, which involved behavioral counseling and nicotine patches. Primary outcomes were rate of program enrollment and rate of smoking abstinence. Potential mediators of smoking cessation were explored (e.g., treatment adherence, depression, anxiety). Two hundred and thirty-four relatives (113 cancer, 121 orthopedic) were considered eligible for the cessation program and comprised the study sample. RESULTS: Relatives of oncology patients were significantly more likely to enroll in the smoking cessation program, vs. orthopedic relatives (75 % vs. 60%; OR = 1.96, 95% CI 1.07-3.61, p = .03), but they were not significantly more likely to remain in the program (61% vs. 52%) or quit smoking (19% vs. 26%; p's > .05). Compared to orthopedic relatives, oncology relatives showed significantly lower nicotine patch adherence and significantly greater levels of negative affect and depression and anxiety symptoms during treatment (p's < .05). Further, orthopedic relatives, compared to oncology relatives, showed a greater reduction in the perceived benefits of smoking (p = .06), which was significantly associated with abstinence (p = .02). CONCLUSIONS: While a family member's cancer diagnosis may serve as a teachable moment for a smoker to enroll in a smoking cessation treatment program, high levels of psychological distress and perceptions of the benefits of smoking and low levels of treatment adherence may undermine successful abstinence among this population.

Tendon sheath fibroma in the thigh.

Tendon sheath fibromas are rare, benign soft tissue tumors that are predominantly found in the fingers, hands, and wrists of young adult men. This article describes a tendon sheath fibroma that developed in the thigh of a 70-year-old man, the only known tendon sheath fibroma to form in this location. Similar to tendon sheath fibromas that develop elsewhere, our patient's lesion presented as a painless, slow-growing soft tissue nodule. Physical examination revealed a firm, nontender mass with no other associated signs or symptoms. Although the imaging appearance of tendon sheath fibromas varies, our patient's lesion appeared dark on T1- and bright on T2-weighted magnetic resonance imaging. It was well marginated and enhanced with contrast.Histologically, tendon sheath fibromas are composed of dense fibrocollagenous stromas with scattered spindle-shaped fibroblasts and narrow slit-like vascular spaces. Most tendon sheath fibromas can be successfully removed by marginal excision, although 24% of lesions recur. No lesions have metastasized. Our patient's tendon sheath fibroma was removed by marginal excision, and the patient remained disease free 35 months postoperatively. Despite its rarity, tendon sheath fibroma should be included in the differential diagnosis of a thigh mass on physical examination or imaging, especially if it is painless, nontender, benign appearing, and present in men.

Impact of close surgical margin on local recurrence and survival in osteosarcoma.

PURPOSE: Whether neoadjuvant chemotherapy safely allows close margins in osteosarcoma patients is still unknown. This study investigates the impact of close margins on local recurrence (LR) and overall survival (OS) for osteosarcoma patients treated with neoadjuvant chemotherapy. METHODS: We retrospectively reviewed 47 cases of conventional osteosarcoma who were treated at our institution. Patient and treatment factors such as age, gender, MSTS stage, tumour site, surgery type, pathological type, tumour size, surgical margin, tumour necrosis rate, chemotherapy regimens and cycles were recorded. A close margin was defined as tumour present less than 5 mm from the closest resection margin. The average followup was 87.6 months (range, 25-135 months). RESULTS: Twenty-five patients were alive, 22 patients had died, and eight had LR. Twenty-eight patients had wide margins, seven had positive margins and 12 had close margins. Positive margins had a greater risk of LR (57.1%) than wide margins and close margins. There was no difference in LR (8.3% vs 10.7%) between close margins and wide margins. Margin status was not correlated with OS. CONCLUSION: Compared with wide margins, close margins did not lead to increased local recurrence in our study group. Whether close margins, as defined in our study, are just as acceptable as wide margins in terms of patient outcomes for osteosarcoma patients with neoadjuvant chemotherapy needs to be further confirmed in the future.