Japanese Orthopaedic Association (JOA) clinical practice guidelines on the management of soft tissue tumors 2020 - Secondary publication.

BACKGROUND: These clinical practice guidelines are intended to provide recommendations based on the best evidence obtained to date on key issues in clinical practice to improve the prognosis, diagnostic and therapeutic processes for patients with soft tissue tumors. METHODS: The Guidelines Development Committee and Systematic Review Committee were composed of a multidisciplinary team of specialists who play an important role in soft tissue tumor care. Clinical questions (CQs) were determined by choosing key decision-making points based on Algorithms for the diagnosis and treatment of soft tissue tumors. The guidelines were developed according to the "Medical Information Network Distribution Service (Minds) Handbook for Clinical Practice Guideline Development 2014" and "Minds Manual for Clinical Practice Guideline Development 2017." Recommendation strength was rated on two levels and the strength of evidence was rated on four levels. The recommendations were decided based on agreement by 70% or more voters. RESULTS: Twenty-two CQs were chosen by the Guidelines Development Committee. The Systematic Review Committee reviewed the evidence concerning each CQ, a clinical value judgment was added by experts, and the text of each recommendation was determined. CONCLUSION: We established 22 CQs and recommendations for key decision-making points in the diagnosis and treatment of soft tissue tumors according to the Minds Clinical Practice Guideline development methods. We hope that these guidelines will assist the decision-making of all medical staff engaged in the treatment and diagnosis of soft tissue tumors, and eventually lead to improved soft tissue tumor care in the country.

Phase II clinical trial of pazopanib for patients with unresectable or metastatic malignant peripheral nerve sheath tumors.

Malignant peripheral nerve sheath tumor (MPNST) often does not respond well to chemotherapy and develops against a background of NF1. The purpose of our study was to examine the efficacy of pazopanib against MPNST. Our study was designed as a physician-initiated phase II clinical trial in patients with advanced MPNST. Patients were registered from 11 large hospitals. The primary endpoint was set to clarify the clinical benefit rate (CBR) at 12 weeks according to response evaluation criteria in solid tumors (RECIST). Progression-free survival (PFS), overall survival (OS) and the CBR based on modified Choi evaluation at week 12 were set as secondary endpoints along with treatment-related safety. The study enrolled 12 patients. Median age was 49 years. Seven had Grade 2 and five Grade 3 according to the FNCLCC evaluation. Median follow-up period was 10.6 months. CBR at 12 weeks was both 50.0% (RECIST and Choi). The median PFS was 5.4 months for both RECIST and Choi, and the median OS was 10.6 months. Of special interest, the median PFS was 2.9 months for patients with FNCLCC Grade 2 and 10.2 months for Grade 3 (both RECIST and Choi). Grade 4 adverse events of neutropenia and lipase elevation were noted in one patient each. The results of this pazopanib therapy were generally better than those of any of the other single molecular targeted therapies reported previously. Although accumulation of more cases remains necessary, we conclude pazopanib treatment for MPNST to be a safe and promising treatment after doxorubicin-based chemotherapy.

Efficacy and safety of TAS-115, a novel oral multi-kinase inhibitor, in osteosarcoma: an expansion cohort of a phase I study.

Background osteosarcoma is a rare, primary malignant bone tumour with limited available treatments for advanced or recurrent disease, resulting in a poor prognosis for patients. TAS-115 is a novel tyrosine kinase inhibitor under investigation in a phase I study in patients with solid tumours. We report data of osteosarcoma patients in the expansion cohort of this ongoing study. Patients and methods an analysis of this multicentre, open-label study was performed 6 months after the final patient was enrolled, and included patients aged ≥15 years, with unresectable or recurrent osteosarcoma, and who had refractory to standard therapy or for whom no standard therapy was available. TAS-115 650 mg/day was orally administered in a 5 days on/2 days off schedule. Results a total of 20 patients with osteosarcoma were enrolled. The most common adverse drug reactions (ADRs) were neutrophil count decreased (75%), aspartate aminotransferase increased (50%), and platelet count decreased (50%); 85% of patients had grade ≥ 3 ADRs. Long-term disease control (>1 year) with TAS-115 was achieved in three patients. The best overall response was stable disease (50%); no patient achieved a complete or partial response. Median progression-free survival was 3 months; 4-month and 12-month progression-free rates were 42% and 31%, respectively. Conclusion the safety and tolerability of TAS-115 and long-term disease stability for patients with unresectable or recurrent osteosarcoma were confirmed in this study, suggesting that TAS-115 is a promising novel therapy for advanced osteosarcoma patients. Trial registration number: JapicCTI-132333 (registered on November 8, 2013).

Giant cell tumor of bone - Analysis of 213 cases involving extra-craniofacial bones.

We elucidated clinicopathological characteristics of giant cell tumor of bone (GCTB) in Japan, and significant clinicopathological factors for predicting local recurrence. Clinicopathological profiles of 213 patients with GCTB (100 male, 113 female) involving extra-craniofacial bones were retrieved. Pathological slides obtained at the initial surgery were reviewed. Fourteen pathological and five clinical features were statistically analyzed to disclose prognostic significance. Patient age ranged from 12-80 years (Average 38.7). Long bones were most frequently affected (86.4%), especially around the knee (62.9%). Histological features are basically similar to those previously reported. Within a follow-up period (24-316 months, average 106.1 months), the local recurrence rate is 29.1%. Metastasis has occurred in 9 patients. Cox regression analysis of representative clinicopathological features shows that younger age, higher mitotic count, smaller zones of stromal hemorrhage, considerable vascular invasion and absence of ischemic necrosis are significant predictors for local recurrence. Initial operative method (curettage) is a significant risk factor in univariate analysis but not by multivariate analysis (P = 0.053). Denosumab administration increases risk but not significantly (P = 0.053). Histone 3.3 G34W immunopositivity is not significant for predicting local recurrence.

Phase II trial of pazopanib in patients with metastatic or unresectable chemoresistant sarcomas: A Japanese Musculoskeletal Oncology Group study.

Alveolar soft part sarcoma (ASPS), epithelioid sarcoma (ES), and clear cell sarcoma (CCS) are known to be chemoresistant tumors. The aim of this study was to investigate the effect of pazopanib on these chemoresistant tumors. This study is designed as a single-arm, multicenter, investigator-initiated phase II trial. Patient enrollment was undertaken between July 2016 and August 2018 at 10 hospitals participating in the Japanese Musculoskeletal Oncology Group. The primary end-point is the CBR (CBR, including complete or partial response and stable disease) at 12 weeks after treatment with pazopanib according to RECIST. Eight patients were enrolled within the period. The histological subtypes were 5 ASPS, 2 ES, and 1 CCS. The median follow-up period was 22.2 (range, 4.9-24.9) months. All patients initially received pazopanib 800 mg once daily. The CBRs were 87.5% (7 of 8) and 75.0% (6 of 8) according to RECIST and Choi criteria at 12 weeks after pazopanib treatment, respectively. The CBRs at 12 weeks according to RECIST were 80.0%, 100.0%, and 100.0% in ASPS, ES, and CCS, respectively. Partial response was observed in 1 ASPS according to RECIST and 3 ASPS and 1 ES according to Choi criteria at 12 weeks after pazopanib treatment. This study documented antitumor activity of pazopanib, especially in ASPS. These results support the frontline use of pazopanib for ASPS. Prospective data collection is desired using both RECIST and Choi criteria for these rare chemoresistant tumors.

Phase I study of TAS-115, a novel oral multi-kinase inhibitor, in patients with advanced solid tumors.

TAS-115 is a novel MET, VEGFR, FMS and PDGFR inhibitor, developed to improve the continuity of drug administration with a relatively short half-life. We assessed its tolerability, safety, pharmacokinetics, efficacy, and pharmacodynamics in patients with solid tumors. This open-label, dose-escalation phase I study of TAS-115 consisted of three parts: part 1 (TAS-115 was administered orally once daily [SID]); part 2 and an expansion part (SID in a 5 days on/2 days off [5-on/2-off] schedule for 21 days per cycle). In part 1 (200-800 mg SID administered to 21 patients), systemic exposure after single administration increased almost dose-proportionally. Three dose-limiting toxicities (DLTs) were observed in three patients: grade 3 rash (650 mg), thrombocytopenia with bleeding, and rash (800 mg). The maximum tolerated dose (MTD) was determined as 650 mg SID. In part 2, the 5-on/2-off schedule was evaluated at the MTD to improve treatment exposure. No DLTs were observed and no patients required treatment interruption in cycle 1. During part 2 and the expansion part (N = 61), grade ≥3 treatment-related adverse events were reported in 47 patients, with neutropenia (24.6%), hypophosphatemia (21.3%), anemia, and thrombocytopenia (14.8% each), and leukocytopenia (11.5%) occurring in ≥10% of patients. The best overall response was stable disease in 31 of 82 patients (37.8%). An apparent reduction in fluorodesoxyglucose-uptake and bone scan index was observed in some patients. TAS-115 was generally well tolerated, with manageable toxicities and recommended phase II dose was estimated as 650 mg SID, 5-on/2-off. Furthermore, promising antitumor activity was observed.

The value of the black fiber sign on T1-weighted images for predicting stability of desmoid fibromatosis managed conservatively.

OBJECTIVES: It is challenging to know at the first which patients with desmoid fibromatosis (DF) are better suited to conservative or aggressive treatment. To investigate whether the low signal intensity bundles on T1- or T2-weighted images (WI), termed the "black fiber sign (BFS)," can predict non-progressive behavior in the conservative approach. METHODS: This retrospective study included 59 patients with primary DF managed with wait-and-see approach from 2005 to 2018 and serial MR images were analyzed. Three observers blinded to the patient information verified the presence or absence of BFS on baseline T1 or T2WI. The likelihood of progression-free survival (PFS) after ascertaining the presence or absence of the BFS was estimated using the Kaplan-Meier method and analyzed with the log-rank test. RESULTS: PFS was significantly higher in cases with BFS than without BFS on T1WI (p < 0.01), but there was no significant difference in PFS between cases with and without BFS on T2WI. Multivariable Cox proportional hazards analysis revealed that the absence of BFS on T1WI was a high-risk factor for progression (hazard ratio, 14.9; p < 0.01). Drastic tumor regression was apparent with significantly increased low-signal area in cases with BFS on T1WI. Intra- and interobserver reliabilities of BFS on T1WI were in almost-perfect agreement (κ > 0.8). CONCLUSION: Our retrospective observational data support that presence of BFS in baseline MRI may be a predictor for progression-free survival of DF. BFS on T1WI is easily identifiable and can be utilized clinically in patients with DF. KEY POINTS: • We proposed a new imaging marker for prediction of desmoid fibromatosis progression. • The absence of black fiber sign predicted a high risk of disease progression.

A long-term follow-up study of extracorporeal irradiated autografts in limb salvage surgery for malignant bone and soft tissue tumors: A minimum follow-up of 10 years after surgery.

BACKGROUND AND OBJECTIVES: The aim of this study is to assess the survival, function, radiographic appearance, and modes of failure of extracorporeal irradiated (ECI) autografts in a long-term setting. METHODS: We retrospectively reviewed 87 patients who were treated for bone and soft tissue tumors using ECI autografts between 1988 and 2009. RESULTS: The 56 patients had a minimum follow-up of 10 years, and the median follow-up period was 16.5 years. The reimplantation procedures included 24 osteoarticular grafts, 16 intercalary grafts, 10 autograft-prosthetic composite grafts, and 6 hemicortical grafts. The 15-year graft and event-free survival rates were 76.8% and 47.9%, respectively. Infection and structural failure were the most common reasons for additional surgery. The time for additional surgery was significantly longer in patients with composite grafts (P < .01). The median Musculoskeletal Tumor Society score and the International Society of Limb Salvage score were 80% and 84%, respectively. CONCLUSIONS: ECI autografts are a durable option for reconstruction after resection of musculoskeletal tumors and provide good function over more than 15 years. Most graft failures occurred within 5 years of the index surgery. However, composite grafts showed a tendency to fail more than 10 years after the surgery.

Clinical outcomes of chondroblastoma treated using synthetic bone substitute: risk factors for developing radiographic joint degeneration.

BACKGROUND: Chondroblastoma (CB) is a rare locally aggressive bone tumor that commonly occurs in the epiphysis or apophysis of long bones. Although surgical treatment of CB carries potential risk for physeal or articular cartilage damage, risk factors for joint degeneration have not been well described. In addition, we have mainly used synthetic bone substitute (SBS) to fill the bone defect after intralesional curettage as treatment for CB. This study thus aimed to evaluate the incidence of and risk factors for adjacent-joint radiographic degeneration after SBS treatment for CB. METHODS: We retrospectively reviewed 48 patients treated for CB at our institutions between 1996 and 2017. Clinical data, radiographic images, treatments, and local recurrence were analyzed. RESULTS: We identified 40 patients [29 males and 11 females with a mean age of 19 years (range, 8-35 years)] who received SBS to fill the defect after curettage with a minimum follow-up of 1 year. The mean follow-up period was 71 months (range, 13-239 months). A total of 8 patients (20%) developed local recurrence. Radiographic analysis showed that 5 patients (16.7%) developed radiographic joint degeneration. Joint degeneration was significantly associated with the affected joint (p = 0.004). CONCLUSIONS: Curettage and SBS filling had been found to be a reasonable treatment method for CB, which commonly occurs in the epiphysis or apophysis. Radiographic joint degeneration was not uncommon after CB treatment, especially in the talus and proximal humerus.

Osteosarcoma in patients over 50 years of age: Multi-institutional retrospective analysis of 104 patients.

BACKGROUND: Primary osteosarcoma in elderly patients are rare malignant tumors. Its optimal treatment has not yet been determined. METHODS: This retrospective study included 104 patients aged >50 years with resectable, non-metastatic osteosarcoma treated by the members of the Bone and Soft Tissue Tumor Study Group of the Japan Clinical Oncology Group. The effects of adjuvant chemotherapy were estimated by comparing outcomes in patients who received surgery plus chemotherapy with those who underwent surgery alone. RESULTS: Median age at presentation was 59 years. Neoadjuvant and adjuvant chemotherapy was administered to 83 (79.8%) patients. Patients who underwent surgery plus chemotherapy and those who underwent surgery alone had 5-year overall survival (OS) rates of 68.6% and 71.7%, respectively (p = 0.780), and 5-year relapse free survival (RFS) rates of 48.2% and 43.6%, respectively (p = 0.64). Univariate analysis showed that resection with wide margins was significantly correlated with better prognosis. CONCLUSIONS: The addition of chemotherapy to surgery did not improve OS or RFS in patients aged >50 years with resectable, non-metastatic osteosarcoma. Surgery with wide margins was only significantly prognostic of improved survival. The effect of chemotherapy in elderly osteosarcoma patients was unclear.

Frequent mutations of genes encoding vacuolar H+ -ATPase components in granular cell tumors.

Granular cell tumors (GCTs) are rare mesenchymal tumors that exhibit a characteristic morphology and a finely granular cytoplasm. The genetic alterations responsible for GCT tumorigenesis had been unknown until recently, when loss-of-function mutations of ATP6AP1 and ATP6AP2 were described. Thus, we performed whole-exome sequencing, RNA sequencing, and targeted sequencing of 51 GCT samples. From these genomic analyses, we identified mutations in genes encoding vacuolar H+ -ATPase (V-ATPase) components, including ATP6AP1 and ATP6AP2, in 33 (65%) GCTs. ATP6AP1 and ATP6AP2 mutations were found in 23 (45%) and 2 (4%) samples, respectively, and all were truncating or splice site mutations. In addition, seven other genes encoding V-ATPase components were also mutated, and three mutations in ATP6V0C occurred on the same amino acid (isoleucine 136). These V-ATPase component gene mutations were mutually exclusive, with one exception. These results suggest that V-ATPase function is impaired in GCTs not only by loss-of-function mutations of ATP6AP1 and ATP6AP2 but also through mutations of other subunits. Our findings provide additional support for the hypothesis that V-ATPase dysfunction promotes GCT tumorigenesis.

Ten-year follow-up results of perioperative chemotherapy with doxorubicin and ifosfamide for high-grade soft-tissue sarcoma of the extremities: Japan Clinical Oncology Group study JCOG0304.

BACKGROUND: Soft-tissue sarcomas (STS) are rare malignant tumors those are resistant to chemotherapy. We have previously reported the 3-year follow-up result on the efficacy of perioperative chemotherapy with doxorubicin (DXR) and ifosfamide (IFM) for high-risk STS of the extremities (JCOG0304). In the present study, we analyzed the 10-year follow-up results of JCOG0304. METHODS: Patients with operable, high-risk STS (T2bN0M0, AJCC 6th edition) of the extremities were treated with 3 courses of preoperative and 2 courses of postoperative chemotherapy, which consisted of 60 mg/m2 of DXR plus 10 g/m2 of IFM over a 3-week interval. The primary study endpoint was progression-free survival (PFS) estimated by Kaplan-Meier methods. Prognostic factors were evaluated by univariable and multivariable Cox proportional hazards model. RESULTS: A total of 72 patients were enrolled between March 2004 and September 2008, with 70 of these patients being eligible. The median follow-up period was 10.0 years for all eligible patients. Local recurrence and distant metastasis were observed in 5 and 19 patients, respectively. The 10-year PFS was 65.7% (95% CI: 53.4-75.5%) with no PFS events being detected during the last 5 years of follow-up. The 10-year overall survival was 78.1% (95% CI: 66.3-86.2%). Secondary malignancy was detected in 6 patients. The subgroup analysis demonstrated that there was significant difference in survival with regard to primary tumor size. CONCLUSIONS: Only a few long-term results of clinical trials for perioperative chemotherapy treatment of STS have been reported. Our results demonstrate that the 10-year outcome of JCOG0304 for patients with operable, high-risk STS of the extremities was stable and remained favorable during the last 5 years of follow-up. TRIAL REGISTRATION: This trial was registered at the UMIN Clinical Trials Registry as C000000096 on August 30, 2005.

Prognostic implication of adjuvant/neoadjuvant chemotherapy consisting of doxorubicin and ifosfamide in patients with extraskeletal osteosarcoma.

BACKGROUND: Extraskeletal osteosarcoma (ESOS) is an extremely rare soft tissue sarcoma. Their prognosis remains poor. Our purposes were to identify the effective chemotherapeutic regimen for ESOS. METHODS: We retrospectively reviewed 16 patients with ESOS treated at the Osaka University Orthopaedic Oncology Group between 1992 and 2012. We extracted the clinical data on patients. Kaplan-Meier method and the log-rank test were used for survival analyses. RESULTS: Median age of the patients was 61.5 years (range 25-79 years). Wide local excision was performed for 11 patients and 9 patients were treated combined with chemotherapy. The 5-year disease-specific survival (DSS) rate was 53.9%. The 5-year DSS rates for patients treated with adjuvant/neoadjuvant chemotherapy or not were 66.7% or 25%, respectively (p = 0.0215). Furthermore, the 5-year DSS rates for patients treated with adjuvant/neoadjuvant chemotherapy consisting of doxorubicin and ifosfamide and those treated with other regimens were 100% or 40%, respectively (p = 0.0327). CONCLUSION: The present study demonstrated that adjuvant/neoadjuvant chemotherapy, especially consisting of doxorubicin and ifosfamide, was potentially efficacious for ESOS. Further prospective study using this multimodality treatment approach to patients with ESOS should be strongly warranted.

Clinical outcomes and significant factors in the survival rate after decompression surgery for patients who were non-ambulatory due to spinal metastases.

BACKGROUND: The development of effective chemotherapy regimens and molecular targeting agents are improving the overall survival rates in patients with cancer. However, patients who are non-ambulatory due to metastatic epidural spinal cord compression (MESCC) may be assessed as unable to tolerate chemotherapy secondary to poor performance status. This means that the ambulatory status of patients with cancer might be significant for survival time. METHODS: We investigated the functional outcomes and factors influencing overall survival in 31 patients who were non-ambulatory due to MESCC and underwent decompression surgery. The functional outcome was determined by the Frankel grading system. RESULT: Twenty-one patients (68%) improved by at least 1 Frankel grade; 17 patients (55%) became ambulatory postoperatively. Most of postoperatively ambulatory patients could undergo postoperative chemotherapy (14/17, 82%). On the other hand, only a few postoperatively non-ambulatory patients could undergo postoperative chemotherapy (2/15, 13%). We observed a complication rate of 35.5% with specific complications including wound infection, pneumonia, and deep vein thrombosis/pulmonary embolus. The median survival duration was 7.0 months. Factors that significantly affected the overall survival in univariate analyses were revised Tokuhashi score (RTS) ≥ 4, postoperative chemotherapy, ambulatory status, and complications (RTS ≥ 4, P < 0.05; postoperative chemotherapy, P < 0.001; ambulatory status, P < 0.001; complications, P < 0.01). CONCLUSIONS: Decompression surgery for patients who are non-ambulatory due to MESCC directly contributes to functional outcomes and may indirectly contribute to overall survival. If non-ambulatory patients who are assessed as unable to tolerate chemotherapy due to poor performance status regain the ability to walk by decompression surgery, they will have a chance to receive postoperative chemotherapy, thereby increasing their chances of prolonging survival. However, postoperative complications may shorten their survival; therefore, we should carefully consider the surgical indications. RTS is useful for judging the surgical indication.

Survival analysis of elderly patients with osteosarcoma.

BACKGROUND: Few studies have described the characteristics and prognostic factors of elderly patients with osteosarcoma. We retrospectively investigated clinico-pathological features and prognostic factors in osteosarcoma patients > 40 years old. METHODS: Patients with high-grade osteosarcoma > 40 years old who were treated at our institutions from 2000 to 2016 were recruited for this study. Information on patient, tumour, and treatment-related factors was collected and statistically analyzed. The median follow-up was 26.5 months (range, 5-139 months) for all patients. RESULTS: Fifty patients (30 males and 20 females) were included. The median age at diagnosis was 59.5 years (range, 41-81 years). The primary lesions were found in the limbs in 32 patients, trunk in 12, and craniofacial bones in six. Primary and secondary osteosarcoma occurred in 41 and 9 patients, respectively. Eight patients exhibited initial distant metastasis. Definitive surgery and chemotherapy were performed in 39 patients each. The rate of good responders after neoadjuvant chemotherapy was 38%. The five year overall survival (OS) rates for all patients and those without distant metastasis at diagnosis were 44.5% and 51.1%, respectively. Multivariate analysis showed that definitive surgery was the only significant prognostic factor in non-metastatic patients. The five year OS and disease-free survival (DFS) rates for non-metastatic patients who received definitive surgery were 64.3% and 60%, respectively. Among these patients, neoadjuvant and/or adjuvant chemotherapy significantly improved both OS and DFS. CONCLUSIONS: Complete surgical resection and intensive chemotherapy should be performed for osteosarcoma patients > 40 years old despite distinct clinicopathological characteristics from those of younger patients.

Clinical outcomes of patients with epithelioid sarcomas: impact and management of nodal metastasis.

PURPOSE: An epithelioid sarcoma is a rare histological subtype of a soft tissue sarcoma with a high local recurrence rate, which frequently shows lymph node metastasis. However, because of the rarity of this tumor, the impact of nodal metastasis and its appropriate management remain unclear. The present study investigated the clinical outcomes of patients with epithelioid sarcomas, with a focus on lymph node metastasis. METHODS: We retrospectively evaluated the clinical outcomes of 27 patients with epithelioid sarcomas treated between 1985 and 2015. The log-rank test was used to assess the prognostic variables. RESULTS: The overall local recurrence rate was 33%, and the estimated overall 5-year survival rate was 62%. Hand and foot locations were associated with favorable overall survival. During the follow-up period, new nodal metastasis was noted in 14 patients (52%). The incidence of local recurrence was higher in patients with new nodal metastasis than in patients who did not develop nodal metastasis. The development of new nodal metastasis had a tendency to worsen survival; however, this association was not statistically significant. Lymphadenectomy did not affect overall survival. CONCLUSIONS: Peripheral tumor location is associated with a better prognosis. The development of new nodal metastasis tends to be associated with poor prognosis; however, among patients with nodal metastasis, resection of the metastatic lesions has a low impact on survival.

Prospective comparison of various radiological response criteria and pathological response to preoperative chemotherapy and survival in operable high-grade soft tissue sarcomas in the Japan Clinical Oncology Group study JCOG0304.

BACKGROUND: Soft tissue sarcomas (STS) are rare malignant tumors. The efficacy of preoperative chemotherapy for STS is evaluated using various tumor size-based radiological response criteria. However, it is still unclear which set of criteria would show the best association with pathological response and survival of the patients with STS. METHODS: We compared radiological responses to preoperative chemotherapy for operable STS by the Response Evaluation Criteria in Solid Tumors (RECIST), modified RECIST, World Health Organization criteria, Japanese Orthopaedic Association criteria, and modified Choi criteria and analyzed the association with pathological response and survival using the data from the Japan Clinical Oncology Group (JCOG) study JCOG0304, a phase II clinical trial evaluating the efficacy of perioperative chemotherapy for STS in the extremities. RESULTS: Seventy eligible patients in JCOG0304 were analyzed. The results demonstrated that none of the size-based radiological response criteria showed significant association with pathological response to preoperative chemotherapy for STS. The difference between overall survival of the patients assessed as partial response and stable disease/progressive disease by RECIST was not significant (hazard ratio 1.37, p = 0.63), and calculated C-index was 0.50. All other response criteria also could not exhibit significant association between radiological responses and survival. CONCLUSION: In the present study, none of the radiological response criteria analyzed demonstrated association of response to preoperative chemotherapy with pathological response or survival of the patients with operable STS. Further prospective investigation is required to develop criteria to evaluate not only tumor shrinkage but biological effects of preoperative chemotherapy for the patients with localized STS. TRIAL REGISTRATION: UMIN Clinical Trials Registry C000000096. Registered 30 August, 2005 (retrospectively registered).

Clinical outcome of primary giant cell tumor of bone after curettage with or without perioperative denosumab in Japan: from a questionnaire for JCOG 1610 study.

BACKGROUND: Giant cell tumor of bone (GCTB) is an intermediate tumor known to be locally aggressive, but rarely metastasizing. To plan a prospective study of GCTB, we performed a questionnaire survey for institutions participating in the Bone and Soft Tissue Tumor Study Group (BSTTSG) in the Japan Clinical Oncology Group (JCOG) in 2015. METHODS: We reviewed 158 consecutive patients with primary GCTB treated with curettage without perioperative denosumab from 2008 to 2010 in Japan. We investigated local and distant recurrence rates after definitive curettage. We also investigated the recurrence rate after treatment with preoperative and/or postoperative denosumab with curettage in recent years. There were 40 patients treated with perioperative denosumab, and the factors affecting recurrence in them were investigated. RESULTS: Answers were available from 24 of 30 institutions (80.0%) participating in JCOG BSTTSG. Thirty (19.0%) and 4 (2.5%) of 158 patients developed local and distant recurrence after curettage without perioperative denosumab from 2008 to 2010, respectively. Campanacci grade and embolization before surgery were significantly associated with increasing incidence of local recurrence after curettage (p = 0.034 and p = 0.022, respectively). In patients treated with perioperative desnosumab, 120 mg denosumab was administered subcutaneously for a median 6 (2-41) and 6 (1-14) times in preoperative and postoperative settings, respectively. The recurrence rates were 6 of 21 (28.6%), 2 of 9 (22.2%), and 0 of 10 (0.0%) in the preoperative, postoperative, and both pre- and postoperative denosumab treatment groups, respectively. With all of the preoperative treatments, administration exceeding five times was significantly associated with a decreased incidence of local recurrence after curettage (p < 0.001). CONCLUSION: The recurrence rate of GCTB was still high after curettage, especially in Campanacci grade III, and improvements in the therapeutic strategy are needed in this cohort. There is a possibility that a sufficient dose of preoperative denosumab can reduce recurrence after curettage. Recently, we have started a clinical trial, JCOG1610, to investigate the efficacy of preoperative denosumab in patients who can be treated with curettage in GCTB.

Therapeutic potential of TAS-115 via c-MET and PDGFRα signal inhibition for synovial sarcoma.

BACKGROUND: The prognosis of synovial sarcoma (SS), an aggressive soft tissue sarcoma, remains poor. We previously reported that c-MET or platelet-derived growth factor receptor α (PDGFRα) signalling pathway is related to SS progression based upon the findings of phospho-receptor tyrosine kinase (RTK) arrays. TAS-115 is a novel c-MET/ vascular endothelial growth factor receptor-targeting tyrosine kinase inhibitor that has been shown to inhibit multiple RTKs. Here we aimed to investigate the therapeutic potential of TAS-115 against SS. METHODS: We first evaluated which signalling pathway was relevant to the viability of three human SS cell lines: Yamato-SS, SYO-1 and HS-SY-II. Next, we assessed the anticancer activity and mechanism of action of TAS-115 in these SS cell lines. Finally, we compared the ability of TAS-115 to inhibit c-MET and PDGFRα phosphorylation with that of pazopanib. RESULTS: We classified the SS cell lines as c-MET-dependent or PDGFRα-dependent based upon the differences in the signalling pathway relevant for growth and/or survival. We also found that c-MET and PDGFRα were the primary activators of both phosphatidylinositol 3-kinase/AKT and mitogen-activated protein kinase pathways in c-MET-dependent and PDGFRα-dependent SS cells, respectively. TAS-115 treatment blocked the phosphorylation of PDGFRα as well as that of c-MET and their downstream effectors, leading to marked growth inhibition in both types of SS cell lines in in vitro and in vivo studies. Furthermore, PDGFRα phosphorylation, on at least four representative autophosphorylation sites, was impeded by TAS-115 equivalently to pazopanib. CONCLUSIONS: These experimental results have demonstrated the significance of c-MET and PDGFRα signalling for growth and/or survival of SS tumours. TAS-115 monotherapy may benefit SS patients whose tumours are dependent upon either c-MET or PDGFRα signalling by functioning as a multiple tyrosine kinase inhibitor to suppress c-MET as well as PDGFRα pathways.

Functional and therapeutic relevance of hepatocyte growth factor/c-MET signaling in synovial sarcoma.

Synovial sarcoma (SS) is an aggressive soft tissue sarcoma with a poor prognosis and, thus, novel therapeutic strategies for SS are urgently required. In the present study, we investigated the functional and therapeutic relevance of hepatocyte growth factor (HGF)/c-MET signaling in SS. Both HGF and c-MET were highly expressed in Yamato-SS cells, resulting in activation of c-MET and its downstream AKT and extracellular signal-regulated kinase signaling pathways, whereas c-MET was expressed but not activated in SYO-1 or HS-SY-II cells. c-MET-activated Yamato-SS cells showed higher anchorage-independent growth ability and less sensitivity to chemotherapeutic agents than did c-MET-inactivated SYO-1 or HS-SY-II cells. INC280, a selective c-MET inhibitor, inhibited growth of Yamato-SS cells both in vitro and in vivo but not that of SYO-1 or HS-SY-II cells. INC280 induced cell cycle arrest and apoptosis, and blocked phosphorylation of c-MET and its downstream effectors in Yamato-SS cells. Co-expression of HGF and c-MET in SS clinical samples correlated with a poor prognosis in patients with SS. Taken together, activation of HGF/c-MET signaling in an autocrine fashion leads to an aggressive phenotype in SS and targeting of this signaling exerts superior antitumor effects on c-MET-activated SS. HGF/c-MET expression status is a potential biomarker for identification of SS patients with a worse prognosis who can benefit from c-MET inhibitors.