Establishment and characterization of 18 Sarcoma Cell Lines: Unraveling the Molecular Mechanisms of Doxorubicin Resistance in Sarcoma Cell Lines.

Sarcomas, malignant tumors from mesenchymal tissues, exhibit poor prognosis despite advancements in treatment modalities such as surgery, radiotherapy, and chemotherapy, with doxorubicin being a cornerstone treatment. Resistance to doxorubicin remains a significant hurdle in therapy optimization. This study aims to dissect the molecular bases of doxorubicin resistance in sarcoma cell lines, which could guide the development of tailored therapeutic strategies. Eighteen sarcoma cell lines from 14 patients were established under ethical approvals and classified into seven subtypes. Molecular, genomic, and transcriptomic analyses included whole-exome sequencing, RNA sequencing, drug sensitivity assays, and pathway enrichment studies to elucidate the resistance mechanisms. Variability in doxorubicin sensitivity was linked to specific genetic alterations, including mutations in TP53 and variations in the copy number of genomic loci like 11q24.2. Transcriptomic profiling divided cell lines into clusters by karyotype complexity, influencing drug responses. Additionally, pathway analyses highlighted the role of signaling pathways like WNT/BETA-CATENIN and HEDGEHOG in doxorubicin-resistant lines. Comprehensive molecular profiling of sarcoma cell lines has revealed complex interplays of genetic and transcriptomic factors dictating doxorubicin resistance, underscoring the need for personalized medicine approaches in sarcoma treatment. Further investigations into these resistance mechanisms could facilitate the development of more effective, customized therapy regimens.

Amputation in patients with extremity soft tissue sarcoma: the experience of an East Asian referral center.

BACKGROUND: This study aimed to investigate the characteristics and clinical outcomes in a series of patients with extremity soft tissue sarcoma (STS) who underwent amputation at a large East Asian referral center. PATIENTS AND METHODS: Of the 652 patients who underwent surgery for extremity STS, data of 37 consecutive patients who underwent amputation were reviewed retrospectively. The median follow-up period was 96.0 months (range, 15-216). The patients were classified in to three cohorts. The primary localized (PL) group included patients who underwent amputation as a primary surgical procedure with curative intent. The recurrent localized (RL) group included patients who underwent amputation as a revision procedure after failure of previous limb sparing surgeries. The metastatic group included patients who underwent amputation as a palliative procedure. RESULTS: There were 22 cases of amputation in 596 STS patients and the amputation rate was 3.6% (22/596). Further, 1.8% (9/490) of patients with primary localized STS underwent amputation. Patients with localized STS who underwent amputation had a 5-year disease-specific survival (DSS) rate of 89.9% (95% Confidence Interval (CI), 87.1-92.7%), a local-recurrence-free survival (LRFS) of 84.1% (95% CI, 80.5-87.6%), and a metastasis-free survival (MFS) of 84.6%. (95% CI, 81.1-88.0%) Compared with previous studies, our results showed higher DSS and MFS rates with similar LRFS. CONCLUSIONS: The amputation rate of extremity STS in our institute in East Asia was similar but slightly lower than that reported in Western studies. The oncologic outcome of amputation reported in this study was higher than that indicated in Western studies and oncologic outcome of amputation was not statistically different from those of limb salvage surgery. However, considering the small cohort in single institute study, there is a possibility of selection bias and future multi-center study is necessary. From our results, amputation is still a feasible option for appropriately selected patients unsuitable for limb-conserving surgery.

Dedifferentiated liposarcoma of the extremities: a Korean multi-center study of 107 cases.

BACKGROUND: Dedifferentiated liposarcoma of the extremities (DDL-E) is rare in comparison to that of the retroperitoneum. Its clinical features and surgical principle for resection margins at the dedifferentiated and the well-differentiated components are yet to be elucidated. METHODS: This retrospective multi-center study examined patients diagnosed with DDL-E from August 2004 to May 2023 at 5 sarcoma centers. Clinical features, oncologic outcomes, and prognostic factors were analyzed. RESULTS: A total of 107 patients were reviewed. The 5-year local recurrence free survival (LRFS), metastasis-free survival (MFS) and disease specific survival (DSS) were 84.7%, 78.6%, and 87.8%, respectively. Other primary malignancies and extrapulmonary metastasis were observed in 27 and 4 patients, respectively. The independent risk factor for local recurrence was R1/2 margin at the dedifferentiated component of the tumor. Metastasis was associated with tumor size in univariate analysis. The independent risk factor for DSS was tumor grade. Previous unplanned excision, de novo presentation, tumor depth, absence of the well-differentiated component, infiltrative border, R1/2 margin at the well-differentiated component were not associated with oncologic outcomes. CONCLUSIONS: This is the largest study examining DDL-E to-date. Localized DDL-E has low potential for metastasis and carries an excellent prognosis. Other primary malignancy and extrapulmonary metastasis are more frequent in DDL-E, thus close monitoring of other sites during follow-up is recommended. While wide resection margin is the standard surgical approach for DDL-E, further investigation into moderated wide resection margin at the well-differentiated component is warranted.

Whole-Genome Sequencing Reveals Mutational Signatures Related to Radiation-Induced Sarcomas and DNA-Damage-Repair Pathways.

Radiation-induced sarcoma (RIS) is a rare but serious late complication arising from radiotherapy. Despite unfavorable clinical outcomes, the genomic footprints of ionizing radiation in RIS development remain largely unknown. Hence, this study aimed to characterize RIS genomes and the genomic alterations in them. We analyzed whole-genome sequencing in 11 RIS genomes matched with normal genomes to identify somatic alterations potentially associated with RIS development. Furthermore, the abundance of mutations, mutation signatures, and structural variants in RIS were compared with those in radiation-naïve spontaneous sarcomas. The mutation abundance in RIS genomes, including one hypermutated genome, was variable. Cancer-related genes might show different types of genomic alterations. For instance, NF1, NF2, NOTCH1, NOTCH2, PIK3CA, RB1, and TP53 showed singleton somatic mutations; MYC, CDKN2A, RB1, and NF1 showed recurrent copy number alterations; and NF2, ARID1B, and RAD51B showed recurrent structural variations. The genomic footprints of nonhomologous end joining are prevalent at indels of RIS genomes compared with those in spontaneous sarcoma genomes, representing the genomic hallmark of RIS genomes. In addition, frequent chromothripsis was identified along with predisposing germline variants in the DNA-damage-repair pathways in RIS genomes. The characterization of RIS genomes on a whole-genome sequencing scale highlighted that the nonhomologous end joining pathway was associated with tumorigenesis, and it might pave the way for the development of advanced diagnostic and therapeutic strategies for RIS.

Does the Clinical Presentation of Secondary Osteosarcoma in Patients Who Survive Retinoblastoma Differ From That of Conventional Osteosarcoma and How Do We Detect Them?

BACKGROUND: Osteosarcoma is the most common secondary malignancy among survivors of retinoblastoma. Most previous reports on secondary malignancy of retinoblastoma included all types of secondary malignancies without a focus on osteosarcoma, owing to its rarity. In addition, there are few studies suggesting tools for regular surveillance for early detection. QUESTIONS/PURPOSES: (1) What are the radiologic and clinical characteristics of secondary osteosarcoma after retinoblastoma? (2) What is the clinical survivorship? (3) Is a radionuclide bone scan a reasonable imaging modality for early detection in patients with retinoblastoma? METHODS: Between February 2000 and December 2019, we treated 540 patients for retinoblastoma. Twelve patients (six male, six female) subsequently developed an osteosarcoma in the extremities; two of these patients had two sites of osteosarcoma (10 femurs, four tibiae) . A Technetium-99m bone scan image was examined annually in all patients for regular surveillance after the treatment of retinoblastoma as per our hospital's policy. All patients were treated with the same strategy as that used for primary conventional osteosarcoma, namely neoadjuvant chemotherapy, wide excision, and adjuvant chemotherapy. The median follow-up period was 12 years (range 8 to 21 years). The median age at the time of diagnosis of osteosarcoma was 9 years (range 5 to 15 years), and the median interval from retinoblastoma diagnosis to osteosarcoma diagnosis was 8 years (range 5 to 15 years). Radiologic characteristics were assessed with plain radiographs and MRI, while clinical characteristics were assessed through a retrospective review of medical records. For clinical survivorship, we evaluated overall survival, local recurrence-free survival, and metastasis-free survival. We reviewed the results of bone scans and clinical symptoms at the time of diagnosis for osteosarcoma after retinoblastoma. RESULTS: In nine of 14 patients, the tumor had a diaphyseal center, and five of the tumors were located at the metaphysis. The femur was the most common site (n = 10), followed by the tibia (n = 4). The median tumor size was 9 cm (range 5 to 13 cm). There was no local recurrence after surgical resection of the osteosarcoma, and the 5-year overall survival rate after the diagnosis of osteosarcoma was 86% (95% CI 68% to 100%). In all 14 tumors, the Technetium bone scan showed increased uptake in the lesions. Ten of 14 tumors were examined in clinic because of patient complaints of pain in the affected limb. Four patients showed no clinical symptoms detected by abnormal uptake on bone scan. CONCLUSION: For unclear reasons, secondary osteosarcomas in patients who were alive after the treatment of retinoblastoma had a slight predilection for the diaphysis of the long bone compared with patients with spontaneous osteosarcoma in other reports. The clinical survivorship of osteosarcoma as a secondary malignancy after retinoblastoma may not be inferior to that of conventional osteosarcoma. Close follow-up with at least yearly clinical assessment and bone scans or other imaging modalities appears to be helpful in detecting secondary osteosarcoma after the treatment of patients with retinoblastoma. Larger multi-institutional studies will be needed to substantiate these observations.Level of Evidenc e Level IV, therapeutic study.

Generation of wavelength-tunable optical vortices using an off-axis spiral phase mirror.

Wavelength-tunable optical vortices with a topological charge equal to l=1 of orbital angular momentum (OAM) were experimentally realized using a single off-axis spiral phase mirror (OSPM) with lasers of various visible-light wavelengths. Using an OSPM designed for 561 nm and an incidence angle of 45°, circular doughnut-shaped l=1 optical vortices were obtained at 561, 473, and 660 nm by rotating the OSPM to modify the laser incidence angle. Wavelength-tunable l=1 optical vortices were obtained at the respective incidence angles of 45°, 53.4°, and 33.7°, because the effective geometrical thickness of the OSPM, which determines the order of OAM, was identical at each wavelength. This flexible OSPM which operates over a wide wavelength range will provide continuously wavelength-tunable optical vortices for applications in the fields of advanced optics and photonics in which optical vortices with wide wavelength tunability are in demand.

Generation of wavelength-tunable optical vortices using an off-axis spiral phase mirror: publisher's note.

This publisher's note contains corrections to Opt. Lett.46, 4216 (2021)OPLEDP0146-959210.1364/OL.432413.

Actual long-term survival after resection of stage III soft tissue sarcoma.

BACKGROUND: Actuarial survival based on the Kaplan-Meier method can overestimate actual long-term survival, especially among those with factors of poor prognosis. Patients with American Joint Committee on Cancer stage III soft tissue sarcoma (STS) represent a subset with a high risk of STS-specific mortality. Therefore, we aimed to characterize the clinicopathological characteristics associated with actual long-term survival in patients with stage III STS. METHODS: We retrospectively reviewed 116 patients who underwent surgical resection for stage III STS with curative intent between March 2000 and December 2013. Long-term survivors (n = 61), defined as those who survived beyond 5 years, were compared with short-term survivors (n = 36), who died of STS within 5 years. RESULTS: Multivariate logistic regression analyses showed that a tumor size < 10 cm [odds ratio (OR) 3.95, p = 0.047], histological grade of 2 (OR 8.12, p = 0.004), and American Society of Anesthesiologists (ASA) score of 1 (OR 11.25, p = 0.001) were independently associated with actual 5-year survival. However, 66% of the long-term survivors exhibited factors of poor prognosis: 36% had a tumor size > 10 cm and 48% had a histological grade of 3. Leiomyosarcoma (3 of 10) was negatively associated with actual long-term survival. CONCLUSIONS: Actual 5-year survival after resection of stage III STS was associated with tumor size, histological grade, and ASA score. However, majority of the actual 5-year survivors exhibit factors of poor prognosis, suggesting that aggressive treatment should be offered for a chance of long-term survival in these patients.

EMMPRIN expression is associated with metastatic progression in osteosarcoma.

BACKGROUND: Extracellular matrix metalloproteinase inducer (EMMPRIN), a cell-surface glycoprotein, is overexpressed in several cancer types. EMMPRIN induces a metastatic phenotype by triggering the production of matrix metalloproteinase proteins (MMPs) such as MMP1 and MMP2, and vascular endothelial growth factor (VEGF) in cancer cells and the surrounding stromal cells. The purpose of this study was to investigate the expression and role of EMMPRIN in osteosarcoma. METHODS: The level of EMMPRIN expression was evaluated using reverse transcriptase polymerase chain reaction (RT-PCR) in 6 tumor-derived osteosarcoma cell lines and compared with that in normal osteoblasts. To study the prognostic significance of EMMPRIN expression, immunohistochemistry was carried out in prechemotherapy biopsies of 54 patients. siRNA knockdown of EMMPRIN in SaOS-2 cells was conducted to explore the role of EMMPRIN. To study the role of EMMPRIN in tumor-stromal interaction in MMP production and invasion, co-culture of SaOS-2 cells with osteoblasts and fibroblasts was performed. Osteosarcoma 143B cells were injected into the tail vein of BALB/c mice and lung metastasis was analyzed. RESULTS: EMMRIN mRNA expression was significantly higher in 5 of 6 (83%) tumor-derived cells than in MG63 cells. 90% of specimens (50/54) stained positive for EMMPRIN by immunohistochemistry, and higher expression of EMMPRIN was associated with shorter metastasis-free survival (p = 0.023). Co-culture of SaOS-2 with osteoblasts resulted in increased production of pro-MMP2 and VEGF expression, which was inhibited by EMMPRIN-targeting siRNA. siRNA knockdown of EMMPRIN resulted in decreased invasion. EMMPRIN shRNA-transfected 143B cells showed decreased lung metastasis in vivo. CONCLUSIONS: Our data suggest that EMMPRIN acts as a mediator of osteosarcoma metastasis by regulating MMP and VEGF production in cancer cells as well as stromal cells. EMMPRIN could serve as a therapeutic target in osteosarcoma.

Ambulation Recovery After Surgery for Metastases to the Femur.

BACKGROUND: Postoperative ambulation recovery after surgery for femur metastases has significant implications for not only the patient's quality of life but also administration of further cancer treatment. Thus, identification of preoperative predictors of ambulation recovery is necessary to set appropriate expectations and guide treatment. This study aimed to assess ambulation recovery rate and identify predictors of ambulation recovery in patients undergoing surgery for femur metastases. MATERIALS AND METHODS: A total of 244 patients who underwent surgery for femur metastases at our institution were reviewed. Patients were considered ambulatory if they were able to walk independently or walk with aids and nonambulatory if they were wheelchair bound or bedridden. The following potential clinicopathologic factors that might predict postoperative ambulation recovery were evaluated: premorbid general status, cancer burden, and local factors. RESULTS: A total of 165 patients (68%) regained ambulatory status postoperatively. A multivariate analysis revealed poor Eastern Cooperative Oncology Group (ECOG) performance status (odds ratio [OR], 5.327; p < .001) and nonambulatory premorbid ambulatory status (OR, 7.459; p < .001) as independent predictors of poor ambulation recovery after surgery for femur metastases. Postoperative ambulatory status was significantly associated with postoperative survival time (p < .001). CONCLUSION: Postoperative ambulation recovery rate in our cohort was 68%. Premorbid ambulatory status and ECOG performance status are predictors of ambulation recovery in patients undergoing surgery for femur metastases. IMPLICATIONS FOR PRACTICE: Postoperative ambulation recovery rate in this cohort was 68%. Premorbid ambulatory status and Eastern Cooperative Oncology Group performance status are predictors of ambulation recovery in patients undergoing surgery for femur metastases.

Changing odds of survival over time among patients undergoing surgical resection of extremity soft tissue sarcoma.

BACKGROUND: While survival after surgical treatment of extremity soft tissue sarcoma (STS) is traditionally reported as actuarial survival, conditional survival (CS) may be more clinically relevant as it accounts for time already survived. We compared actuarial survival and CS of STS patients. MATERIALS AND METHODS: We analyzed 567 patients who underwent surgery for localized extremity STS. Actuarial survival was estimated using the Kaplan-Meier method. Cox proportional hazards model was used to evaluate factors associated with disease-specific survival. Five-year CS (CS5) estimates at "χ" year(s) after surgery were calculated as CS5 = S(χ + 5)/S(χ). RESULTS: Whereas actuarial survival decreased over time, CS5 increased. The postsurgical 1-, 3-, and 5-year CS5 values were 84.5%, 90.0%, and 93.8%, respectively, whereas the 6-, 8-, and 10-year actuarial survival rates were 82.0%, 79.4%, and 78.5%, respectively. The calculated CS5 exceeded actuarial survival especially in patients with risk factors such as large tumor size and Federation Nationale des Centers de Lutte Contre le Cancer (FNCLCC) grades 2 and 3 tumors. Patients with tumor size ≥5 cm had an actuarial survival of 73.9% at 10 years compared to a CS5 of 95.4% in patients alive at 5 years. Likewise, patients with FNCLCC grade 3 tumors had an actuarial survival of 71.1% at 10 years compared to a CS5 of 96.0% in patients alive at 5 years. CONCLUSIONS: Survival estimation by determination of CS can be dynamic and accurate especially in high-risk patients. CS can be useful for survival prediction and clinical decision making in extremity STS patients.

Deep learning approach for survival prediction for patients with synovial sarcoma.

Synovial sarcoma is a rare disease with diverse progression characteristics. We developed a novel deep-learning-based prediction algorithm for survival rates of synovial sarcoma patients. The purpose of this study is to evaluate the performance of the proposed prediction model and demonstrate its clinical usage. The study involved 242 patients who were diagnosed with synovial sarcoma in three institutions between March 2001 and February 2013. The patients were randomly divided into a training set (80%) and a testing set (20%). Fivefold cross validation was performed utilizing the training set. The test set was retained for the final testing. A Cox proportional hazard model, simple neural network, and the proposed survival neural network were all trained utilizing the same training set, and fivefold cross validation was performed. The final testing was performed utilizing the isolated test data to determine the best prediction model. The multivariate Cox proportional hazard regression analysis revealed that size, initial metastasis, and margin were independent prognostic factors. In fivefold cross validation, the median value of the receiver-operating characteristic curve (area under the curve) was 0.87 in the survival neural network, which is significantly higher compared to the area under the curve of 0.792 for the simple neural network (p = 0.043). In the final test, survival neural network model showed the better performance (area under the curve: 0.814) compared to the Cox proportional hazard model (area under the curve: 0.629; p = 0.0001). The survival neural network model predicted survival of synovial sarcoma patients more accurately compared to Cox proportional hazard model.

Factors associated with local recurrence after surgery for bone metastasis to the extremities.

BACKGROUND AND OBJECTIVES: With increasing life expectancy of patients with bone metastasis, durable surgical stabilization of bone metastasis is necessary. Local recurrence (LR) can compromise surgical stabilization and necessitate retreatment. We analyzed LR rate and factors associated with LR in patients undergoing surgery for bone metastasis. METHODS: Patients (n = 301) who underwent surgery for bone metastasis to the extremities were reviewed. Possible factors that might be associated with LR were investigated. RESULTS: LR rate was 16% (49/301). Surgical margin was associated with LR, as patients with en-bloc resection had significantly less LR than patients who underwent curettage (5/66 vs 44/235, P = 0.03). Prostate cancer had lowest rate (0%) of LR and colon cancer had highest rate (31%). Interval from surgery to LR differed among primary cancer types (4.5 ± 3.9 months [lung cancer], vs 12.3 ± 12.9 months [other cancers], P = 0.041). In multivariate analysis, en-bloc surgical margins (HR = 0.372, P = 0.036) and primary cancers of breast or prostate (HR = 0.391, P = 0.049) were independent factors associated with longer LR-free survival. CONCLUSIONS: LR after surgery for bone metastasis to extremities is affected by surgical margin and primary cancer type. These factors, along with expected patient survival, need to be considered when planning surgery for bone metastasis to extremities.

Postmetastasis survival in high-grade extremity osteosarcoma: A retrospective analysis of prognostic factors in 126 patients.

BACKGROUND AND OBJECTIVES: Prognostic factors predictive of postmetastasis survival (PMS) in metastatic osteosarcoma are poorly understood. Our aims were to evaluate PMS in patients with high-grade osteosarcoma in extremities, and to identify prognostic factors related to PMS. METHODS: A retrospective review of data for 126 patients with metastatic osteosarcoma was conducted. The study population consisted of 70 men and 56 women, with a mean age of 21 years (range: 4-75 years). The mean postmetastasis follow-up period was 37 months (range: 1-245 months). RESULTS: The 5-year PMS rate was 31% and median PMS duration was 22 months. In the multivariate analyses, no metastasectomy (P < 0.001), local recurrence prior to metastasis (P = 0.016), extrapulmonary metastasis (P = 0.006), and poor histologic response to preoperative chemotherapy (P = 0.047) were significant poor prognostic factors. The 5-year PMS without any negative prognostic factor was 60.2%; with one factor, 31.6%; and with more than two factors, 3.6%. CONCLUSIONS: PMS in osteosarcoma patients was influenced by primary tumor-related factors such as histologic response to chemotherapy, as well as metastasis-related factors such as complete metastasectomy and metastasis site. A certain group of patients without such poor prognostic factors could be cured even after the development of metastasis.

Can Augmented Reality Be Helpful in Pelvic Bone Cancer Surgery? An In Vitro Study.

BACKGROUND: Application of surgical navigation for pelvic bone cancer surgery may prove useful, but in addition to the fact that research supporting its adoption remains relatively preliminary, the actual navigation devices are physically large, occupying considerable space in already crowded operating rooms. To address this issue, we developed and tested a navigation system for pelvic bone cancer surgery assimilating augmented reality (AR) technology to simplify the system by embedding the navigation software into a tablet personal computer (PC). QUESTIONS/PURPOSES: Using simulated tumors and resections in a pig pelvic model, we asked: Can AR-assisted resection reduce errors in terms of planned bone cuts and improve ability to achieve the planned margin around a tumor in pelvic bone cancer surgery? METHODS: We developed an AR-based navigation system for pelvic bone tumor surgery, which could be operated on a tablet PC. We created 36 bone tumor models for simulation of tumor resection in pig pelves and assigned 18 each to the AR-assisted resection group and conventional resection group. To simulate a bone tumor, bone cement was inserted into the acetabular dome of the pig pelvis. Tumor resection was simulated in two scenarios. The first was AR-assisted resection by an orthopaedic resident and the second was resection using conventional methods by an orthopaedic oncologist. For both groups, resection was planned with a 1-cm safety margin around the bone cement. Resection margins were evaluated by an independent orthopaedic surgeon who was blinded as to the type of resection. All specimens were sectioned twice: first through a plane parallel to the medial wall of the acetabulum and second through a plane perpendicular to the first. The distance from the resection margin to the bone cement was measured at four different locations for each plane. The largest of the four errors on a plane was adopted for evaluation. Therefore, each specimen had two values of error, which were collected from two perpendicular planes. The resection errors were classified into four grades: ≤ 3 mm; 3 to 6 mm; 6 to 9 mm; and > 9 mm or any tumor violation. Student's t-test was used for statistical comparison of the mean resection errors of the two groups. RESULTS: The mean of 36 resection errors of 18 pelves in the AR-assisted resection group was 1.59 mm (SD, 4.13 mm; 95% confidence interval [CI], 0.24-2.94 mm) and the mean error of the conventional resection group was 4.55 mm (SD, 9.7 mm; 95% CI, 1.38-7.72 mm; p < 0.001). All specimens in the AR-assisted resection group had errors < 6 mm, whereas 78% (28 of 36) of errors in the conventional group were < 6 mm. CONCLUSIONS: In this in vitro simulated tumor model, we demonstrated that AR assistance could help to achieve the planned margin. Our model was designed as a proof of concept; although our findings do not justify a clinical trial in humans, they do support continued investigation of this system in a live animal model, which will be our next experiment. CLINICAL RELEVANCE: The AR-based navigation system provides additional information of the tumor extent and may help surgeons during pelvic bone cancer surgery without the need for more complex and cumbersome conventional navigation systems.

Cortical Atrophy Related to Tumor Prosthesis in Skeletally Immature Osteosarcoma Patients.

BACKGROUND: Cortical atrophy is commonly observed after prosthetic reconstruction for bone sarcomas. However, relevant literature regarding this phenomenon in skeletally immature patients is limited. Therefore, in this study, we evaluated the incidence and patterns of cortical atrophy. We then assessed its predisposing factors. Finally, we analyzed whether cortical atrophy was associated with poor prosthesis survival. METHODS: We retrospectively reviewed 31 stems in 19 skeletally immature osteosarcoma patients who were treated with resection and tumor prosthesis surgery. We measured the cortical thickness using plain radiographs annually. The mean patient age was 11 years (range, 6 to 14 y) and the mean follow-up period was 10 years (range, 2 to 14 y). RESULTS: Cortical atrophy developed in 13 stems, all within 3 years. There were 3 gross types of cortical atrophy: hourglass in 5, sharpening in 4, and shortening atrophy in 4. On multivariate analysis, stem-cortex diameter ratio of ≥0.5 and age of less than 10 years were significantly associated with cortical atrophy (P=0.002 and P=0.019, respectively). Cortical atrophy was significantly associated with eventual prosthesis failure (9/13 in the cortical atrophy group vs. 4/18 in the nonatrophy group, P=0.035). CONCLUSIONS: Cortical atrophy is common in the skeletally immature patients with tumor prosthesis and is associated with prosthesis failure. Patients with cortical atrophy should be closely monitored for prosthesis failure and appropriately managed to prevent failures. LEVEL OF EVIDENCE: Level IV-therapeutic study.

Optimal Treatment of Osteofibrous Dysplasia of the Tibia.

BACKGROUND: Our study of a large patient group reports on the behavior and postoperative recurrence of osteofibrous dysplasia (OFD). METHODS: We reviewed the medical records of 55 patients who were diagnosed with OFD of the tibia and showed typical features of this tumor. The patients' presentation, disease course, history of pathologic fracture, typical radiographic features, surgical treatment history, and surgical results were investigated. RESULTS: The longitudinal OFD lesion size peaks at a mean 13.3 years of age with a mean maximum proportionate size of 0.33. These lesions in 92% of the patients spontaneously presented with a stable disease course, while those in the other 8% continued increasing. There were no significant predictive factors of disease course. Among surgically treated lesions, we noted a higher rate of recurrence after curettage than after excision (P<0.001). Patients who underwent curettage and developed recurrence were significantly younger than those who did not (P=0.01). CONCLUSIONS: Our data suggest that observation can be the primary form of treatment for patients with OFD and that the disease would stop advancing with time. During observation, clinicians should carefully observe all patients with OFD because the relation between OFD and adamantinoma is unclear. If surgery is necessary due to severe morbidity, we recommend excision rather than curettage to prevent recurrence, especially for younger patients. LEVEL OF EVIDENCE: Level III.

Surveillance for lung metastasis from giant cell tumor of bone.

BACKGROUND AND OBJECTIVES: Literature on surveillance for lung metastasis from giant cell tumor of bone (GCTB) is scarce. We aimed to develop one by determining: (1) the optimal surveillance schedule by analyzing time-to-event data, taking into account the predictive factors, and (2) the effective diagnostic modality. METHODS: A total of 333 patients who underwent surgery for GCTB were followed for at least 2 years. All had chest radiography, and 169 had additional CT for surveillance. Time to lung metastasis and cumulative incidence were calculated, and diagnostic performance between chest radiography and CT was compared. RESULTS: Twenty-five (7.5%) of 333 patients developed lung metastasis, and local recurrence (LR) was the only predictive factor (RR = 6.54). Median interval from LR to metastasis was 15 months, and 17 (85%) of the 20 metastases with LR occurred within 3 years of LR. Cumulative post-LR incidences at 1, 3, and 5 years were 15.4%, 21.5%, and 21.5%, respectively. CT was more sensitive (100% vs 32%), and had higher positive predictive value (81% vs 57%) and accuracy (96% vs 93%). CONCLUSIONS: Intensified lung surveillance is warranted for GCTB patients with LR, especially for 3 years from diagnosis of LR. CT is effective for detecting lung metastasis from GCTB.

Association of core needle biopsy tract resection with local recurrence in extremity soft tissue sarcoma.

OBJECTIVE: Due to minimal tissue violation in percutaneous core needle biopsy (CNB), in contrast to open biopsy, the risk of tumor seeding and subsequent local recurrence (LR) along the biopsy tract remains unclear in extremity soft tissue sarcoma (STS). This study sought to examine the association of CNB tract resection on LR in a large STS institutional database. MATERIALS AND METHODS: After a retrospective review of the 116 patients who underwent CNB prior to surgery for previously untreated non-metastatic extremity STS, 36 patients who did not have CNB tracts resected (CNB-NR) were matched with 36 who had CNB tracts resected (CNB-R) for the factors that are known to affect LR. RESULTS: Two patients (6%) developed LR in the CNB-R group, whereas three patients (8%) developed LR in the CNB-NR group (P = 0.643). On Kaplan-Meier analysis, there was no significant difference in LR-free survival between the two groups (94.3% ± 3.9 for the CNB-R group vs. 93.8% ± 4.3 for the CNB-NR group, P = 0.747). CONCLUSION: Our data suggest any influence of a CNB tract resection on LR, within the limitations of this study, is likely to be of minor clinical importance in extremity STS. Although it would be prudent to resect the CNB tract in most cases, not resecting the CNB tract is a feasible option if identification or removal of the CNB tract proves difficult.

Wavelength independent all-fiber angle-tunable polarization rotator based on geometric effects.

We propose and demonstrate a simple wavelength independent all-fiber polarization rotator based on purely geometric effects. The device rotates the orientation of an arbitrary input polarization state by arbitrary angle without changing other parameters of the polarization state. The device structure maintains inherent wavelength independence during the tuning process when a non-birefringent single-mode fiber is used.