ABSTRACT
Tenosynovial giant cell tumour (TGCT) is a rare, locally aggressive, mesenchymal tumor arising from the joints, bursa and tendon sheaths. TGCT comprises a nodular- and a diffuse-type, with the former exhibiting mostly indolent course and the latter a locally aggressive behavior. Although usually not life-threatening, TGCT may cause chronic pain and adversely impact function and quality of life (QoL). CSFR1 inhibitors are effective with benefit on symptoms and QoL but are not available in most countries. The degree of uncertainty in selecting the most appropriate therapy and the lack of guidelines on the clinical management of TGCT make the adoption of new treatments inconsistent across the world, with suboptimal outcomes for patients. A global consensus meeting was organized in June 2022, involving experts from several disciplines and patient representatives from SPAGN to define the best evidence-based practice for the optimal approach to TGCT and generate the recommendations presented herein.
Subject(s)
Giant Cell Tumor of Tendon Sheath , Quality of Life , Humans , Consensus , Giant Cell Tumor of Tendon Sheath/drug therapy , Giant Cell Tumor of Tendon Sheath/pathologyABSTRACT
BACKGROUND: The Complexity INdex in SARComas (CINSARC) is a transcriptional signature derived from the expression of 67 genes involved in mitosis control and chromosome integrity. This study aims to assess CINSARC value of in an independent series of high-risk patients with localized soft tissue sarcoma (STS) treated with preoperative chemotherapy within a prospective, randomized, phase III study (ISG-STS 1001). PATIENTS AND METHODS: Patients with available pre-treatment samples, treated with 3 cycles of either standard (ST) preoperative or histotype-tailored (HT) chemotherapy, were scored according to CINSARC (low-risk, C1; high-risk, C2). The 10-year overall survival probability (pr-OS) according to SARCULATOR was calculated, and patients were classified accordingly (low-risk, Sarc-LR, 10-year pr-OS>60%; high-risk, Sarc-HR, 10-year pr-OS<60%). Survival functions were estimated using the Kaplan-Meier method and compared using log-rank test. RESULTS: Eighty-six patients were included, 30 C1 and 56 C2, 49 Sarc-LR and 37 Sarc-HR. A low level of agreement between CINSARC and SARCULATOR was observed (Cohen's Kappa = 0.174). The 5-year relapse-free survival in C1 and C2 were 0.57 and 0.55 (p = 0.481); 5-year metastases-free survival 0.63 and 0.64 (p = 0.740); 5-year OS 0.80 and 0.72 (p = 0.460). The 5-year OS in C1 treated with ST and HT chemotherapy was 0.84 and 0.76 (p = 0.251) respectively; in C2 treated it was 0.72 and 0.70 (p = 0.349). The 5-year OS in Sarc-LR treated with S and HT chemotherapy was 0.80 and 0.82 (p = 0.502) respectively; in Sarc-HR it was 0.70 and 0.61 (p = 0.233). CONCLUSIONS: Our results, although constrained by the small size of the series, suggest that CINSARC has weak prognostic power in high-risk, localized STS treated with neoadjuvant chemotherapy.
Subject(s)
Sarcoma , Soft Tissue Neoplasms , Humans , Neoadjuvant Therapy , Prospective Studies , Neoplasm Recurrence, Local , Sarcoma/drug therapy , Sarcoma/genetics , PrognosisABSTRACT
OPINION STATEMENT: Leiomyosarcoma is one of the most common subtypes of soft tissue sarcomas accounting for approximately 20% of sarcomas. As leiomyosarcoma patients frequently develop metastatic disease, effective systemic therapies are needed to improve clinical outcomes. The overall activity of the currently available conventional systemic therapies and the prognosis of patients with advanced and/or metastatic disease are poor. As such, the treatment of this patient population remains challenging. As a result, there is a clear unmet medical need, and designing and performing meaningful clinical studies are of utmost importance to improve the prognosis of this patient group. Therefore, the aim of this review is to briefly summarize state-of-the-art treatments for leiomyosarcoma patients and to describe trial characteristics needed for informative clinical studies.
Subject(s)
Leiomyosarcoma , Sarcoma , Soft Tissue Neoplasms , Humans , Leiomyosarcoma/diagnosis , Leiomyosarcoma/drug therapy , Prognosis , Sarcoma/diagnosis , Sarcoma/etiology , Sarcoma/therapy , Soft Tissue Neoplasms/pathologyABSTRACT
In the first-line setting of advanced soft tissue sarcomas (STS), the treatment aim generally drives decision-making. Anthracycline combinations with ifosfamide or dacarbazine are more appropriate when the aim is tumour shrinkage, and doxorubicin monotherapy is suitable for tumour control. In patients who progress on anthracycline-based regimens, scope exists for tumour shrinkage with trabectedin and concurrent low-dose radiotherapy. Selecting systemic treatment for patients with advanced STS unsuited to receive standard anthracycline-based therapy often involves complex decision-making as clinical trial evidence comparing alternative options is lacking. Key factors to consider are patient characteristics (e.g., age, medical history, performance status), disease characteristics (e.g., stage, histology), and treatment requirements such as the drug's safety profile, evidence of efficacy by subtype, and approved indication as an alternative first-line treatment option. Real-world data for elderly STS patients derived from retrospective studies and post hoc analyses of clinical trials have particular value in guiding treatment selection and improving the management of this populous but undertreated segment of the STS population.
Subject(s)
Sarcoma/therapy , Aged , Cell Line, Tumor , Chemoradiotherapy , Clinical Trials as Topic , Humans , Male , Middle Aged , Sarcoma/mortality , Trabectedin/therapeutic useABSTRACT
BACKGROUND: This observational, retrospective effort across Europe, US, Australia, and Asia aimed to assess the activity of systemic therapies in EHE, an ultra-rare sarcoma, marked by WWTR1-CAMTA1 or YAP1-TFE3 fusions. METHODS: Twenty sarcoma reference centres contributed data. Patients with advanced EHE diagnosed from 2000 onwards and treated with systemic therapies, were selected. Local pathologic review and molecular confirmation were required. Radiological response was retrospectively assessed by local investigators according to RECIST. Progression free survival (PFS) and overall survival (OS) were estimated by Kaplan-Meier method. RESULTS: Overall, 73 patients were included; 21 had more than one treatment. Thirty-three patients received anthracyclines regimens, achieving 1 (3%) partial response (PR), 25 (76%) stable disease (SD), 7 (21%) progressive disease (PD). The median (m-) PFS and m-OS were 5.5 and 14.3 months respectively. Eleven patients received paclitaxel, achieving 1 (9%) PR, 6 (55%) SD, 4 (36%) PD. The m-PFS and m-OS were 2.9 and 18.6 months, respectively. Twelve patients received pazopanib, achieving 3 (25%) SD, 9 (75%) PD. The m-PFS and m-OS were.2.9 and 8.5 months, respectively. Fifteen patients received INF-α 2b, achieving 1 (7%) PR, 11 (73%) SD, 3 (20%) PD. The m-PFS and m-OS were 8.9 months and 64.3, respectively. Among 27 patients treated with other regimens, 1 PR (ifosfamide) and 9 SD (5 gemcitabine +docetaxel, 2 oral cyclophosphamide, 2 others) were reported. CONCLUSION: Systemic therapies available for advanced sarcomas have limited activity in EHE. The identification of new active compounds, especially for rapidly progressive cases, is acutely needed.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Hemangioendothelioma, Epithelioid/drug therapy , Sarcoma/drug therapy , Adult , Female , Follow-Up Studies , Hemangioendothelioma, Epithelioid/pathology , Humans , International Agencies , Male , Middle Aged , Prognosis , Retrospective Studies , Sarcoma/pathology , Survival RateABSTRACT
BACKGROUND: Locally advanced soft tissue sarcoma (STS) management may include neoadjuvant or adjuvant treatment by radiotherapy (RT), chemotherapy (CT) or chemoradiotherapy (CRT) followed by wide surgical excision. While pathological complete response (pCR) to preoperative treatment is prognostic for survival in osteosarcomas, its significance for STS is unclear. We aimed to evaluate the prognostic significance of pCR to pre-operative treatment on 3-year disease-free survival (3y-DFS) in STS patients. METHODS: This is an observational, retrospective, international, study of adult patients with primary non-metastatic STS of the extremities and trunk wall, any grade, diagnosed between 2008 and 2012, treated with at least neoadjuvant treatment and surgical resection and observed for a minimum of 3 years after diagnosis. The primary objective was to evaluate the effect of pCR. (≤5% viable tumor cells or ≥95% necrosis/fibrosis) on 3y-DFS. Effect on local recurrence-free survival (LRFS), distant recurrence-free survival (MFS) overall survival (OS) at 3 years was also analyzed. Statistical univariate analysis utilized chi-square independence test and odds ratio confidence interval (CI) estimate, multivariate analysis was performed using LASSO. RESULTS: A total of 330 patients (median age 56 years old, range:19-95) treated by preoperative RT (67%), CT (15%) or CRT (18%) followed by surgery were included. pCR was achieved in 74/330 (22%) of patients, of which 56/74 (76%) had received RT. 3-yr DFS was observed in 76% of patients with pCR vs 61% without pCR (p < 0.001). Multivariate analysis showed that pCR is statistically associated with better MFS (95% CI, 1.054-3.417; p = 0.033), LRFS (95% CI, 1.226-5.916; p = 0.014), DFS (95% CI, 1.165-4.040; p = 0.015) and OS at 3 years (95% CI, 1.072-5.210; p = 0.033). CONCLUSIONS: In a wide, heterogeneous STS population we showed that pCR to preoperative treatment is prognostic for survival.
Subject(s)
Antineoplastic Agents/therapeutic use , Chemoradiotherapy/methods , Neoadjuvant Therapy/methods , Sarcoma/therapy , Soft Tissue Neoplasms/therapy , Adult , Aged , Aged, 80 and over , Disease-Free Survival , Extremities/pathology , Extremities/surgery , Female , Humans , Leiomyosarcoma/pathology , Leiomyosarcoma/therapy , Liposarcoma/pathology , Liposarcoma/therapy , Liposarcoma, Myxoid/pathology , Liposarcoma, Myxoid/therapy , Male , Margins of Excision , Middle Aged , Multivariate Analysis , Proportional Hazards Models , Radiotherapy/methods , Retrospective Studies , Sarcoma/pathology , Soft Tissue Neoplasms/pathology , Surgical Procedures, Operative , Torso/pathology , Torso/surgery , Young AdultABSTRACT
Background: High-grade sarcomas are a heterogeneous group of aggressive tumors arising in bone and soft tissues. After relapse, treatment options are limited. The multi-targeted receptor tyrosine kinase inhibitors (TKIs) sunitinib and inhibitor of PD-1 (anti-PD-1) nivolumab have shown antitumor activity in selected subtypes. In this study, we examine the role of TKIs and PD-1 based therapy in in vitro cocultures of sarcoma. Methods: The human osteosarcoma (SaOS-2) and synovial sarcoma (SYO-1) cell lines were treated with sunitinib. After cell death and proliferation assessment, expression of PD-L1 was analyzed by flow cytometry. Sunitinib-treated sarcoma cells were cocultured with dendritic cells (DCs), and the phenotype of mature DCs was determined by flow cytometry. Mature DCs were cultured with autologous T cells. PD-1 expression on T cells, their proliferation, T regulatory cell (Tregs) induction and IFN-γ production, before and after nivolumab exposure, were analyzed. Results: Along with its anti-proliferative and direct pro-apoptotic effect on sarcoma cell lines, sunitinib prompted PD-L1 upregulation on sarcoma cells. Interestingly, sunitinib-treated sarcoma cells drive DCs to full maturation and increase their capacity to induce sarcoma-reactive T cells to produce IFN-γ. Conversely, no effect on T cell proliferation and T cell subpopulation composition was observed. Moreover, both bone and synovial sarcoma cell lines induced Tregs through DCs but sunitinib treatment completely abrogated Treg induction. Finally, sarcoma cell lines induced PD-1 upregulation on both effector T cells and Tregs when loaded into DCs, providing a rationale for using PD-1 blockade. Indeed, PD-1 blockade by nivolumab synergized with sunitinib in inducing IFN-γ-producing effector T cells. Conclusions: Taken together, our in vitro data indicate that the treatment of sarcoma cells with sunitinib can exert significant changes on immune cell subsets toward immune activation, leading to DC-based cross-priming of IFN-γ-producing effector T cells and reduced Treg induction. PD-1 blockade with nivolumab has a synergistic effect with sunitinib, supporting the use of TKI and anti-PD-1 approach in sarcomas, and perhaps in other cancers. DC-targeted drugs, including toll-like receptor 3 inhibitors and CD47 inhibitors, are under development and our preclinical model might help to better design their clinical application.
Subject(s)
Dendritic Cells/drug effects , Dendritic Cells/immunology , Dendritic Cells/metabolism , Immune Checkpoint Inhibitors/pharmacology , Immunomodulation/drug effects , Programmed Cell Death 1 Receptor/antagonists & inhibitors , Sunitinib/pharmacology , Apoptosis/drug effects , Biomarkers , Cell Line, Tumor , Cell Proliferation/drug effects , Humans , Immunophenotyping , Interferon-gamma/metabolism , Lymphocyte Activation/drug effects , Protein Kinase Inhibitors/pharmacology , T-Lymphocyte Subsets/immunology , T-Lymphocyte Subsets/metabolism , T-Lymphocytes, Regulatory/drug effects , T-Lymphocytes, Regulatory/immunology , T-Lymphocytes, Regulatory/metabolismABSTRACT
Importance: The association between quality of surgery and overall survival in patients affected by localized gastrointestinal stromal tumors (GIST) is not completely understood. Objective: To assess the risk of death with and without imatinib according to microscopic margins status (R0/R1) using data from a randomized study on adjuvant imatinib. Design, Setting, and Participants: This is a post hoc observational study on patients included in the randomized, open-label, phase III trial, performed between December 2004 and October 2008. Median follow-up was 9.1 years (IQR, 8-10 years). The study was performed at 112 hospitals in 12 countries. Inclusion criteria were diagnosis of primary GIST, with intermediate or high risk of relapse; no evidence of residual disease after surgery; older than 18 years; and no prior malignancies or concurrent severe/uncontrolled medical conditions. Data were analyzed between July 17, 2017, and March 1, 2020. Interventions: Patients were randomized after surgery to either receive imatinib (400 mg/d) for 2 years or no adjuvant treatment. Randomization was stratified by center, risk category (high vs intermediate), tumor site (gastric vs other), and quality of surgery (R0 vs R1). Tumor rupture was included in the R1 category but also analyzed separately. Main Outcomes and Measures: Primary end point of this substudy was overall survival (OS), estimated using Kaplan-Meier method and compared between R0/R1 using Cox models adjusted for treatment and stratification factors. Results: A total of 908 patients were included; 51.4% were men (465) and 48.6% were women (440), and the median age was 59 years (range, 18-89 years). One hundred sixty-two (17.8%) had an R1 resection, and 97 of 162 (59.9%) had tumor rupture. There was a significant difference in OS for patients undergoing an R1 vs R0 resection, overall (hazard ratio [HR], 2.05; 95% CI, 1.45-2.89) and by treatment arm (HR, 2.65; 95% CI, 1.37-3.75 with adjuvant imatinib and HR, 1.86; 95% CI, 1.16-2.99 without adjuvant imatinib). When tumor rupture was excluded, this difference in OS between R1 and R0 resections disappeared (HR, 1.05; 95% CI, 0.54-2.01). Conclusions and Relevance: The difference in OS by quality of surgery with or without imatinib was associated with the presence of tumor rupture. When the latter was excluded, the presence of R1 margins was not associated with worse OS. Trial Registration: ClinicalTrials.gov Identifier: NCT00103168.
Subject(s)
Antineoplastic Agents/therapeutic use , Gastrointestinal Neoplasms/drug therapy , Gastrointestinal Neoplasms/surgery , Gastrointestinal Stromal Tumors/drug therapy , Gastrointestinal Stromal Tumors/surgery , Imatinib Mesylate/therapeutic use , Adolescent , Adult , Aged , Aged, 80 and over , Chemotherapy, Adjuvant , Digestive System Surgical Procedures/standards , Female , Humans , International Cooperation , Male , Middle Aged , Quality of Health Care , Treatment Outcome , Young AdultABSTRACT
Importance: Epithelioid sarcoma (ES) is an exceedingly rare malignant neoplasm with distinctive pathologic, molecular, and clinical features as well as the potential to respond to new targeted drugs. Little is known on the activity of anthracycline-based regimens, gemcitabine-based regimens, and pazopanib in this disease. Objective: To report on the activity of anthracycline-based regimens, gemcitabine-based regimens, and pazopanib in patients with advanced ES. Design, Setting, and Participants: Seventeen sarcoma reference centers in Europe, the United States, and Japan contributed data to this retrospective analysis of patients with locally advanced/metastatic ES diagnosed between 1990 and 2016. Local pathological review was performed in all cases to confirm diagnosis according to most recent criteria. Exposures: All patients included in the study received anthracycline-based regimens, gemcitabine-based regimens, or pazopanib. Main Outcome and Measures: Response was assessed by RECIST. Progression-free survival (PFS) and overall survival (OS) were computed by Kaplan-Meier method. Classic and proximal subtypes were defined based on morphology (according to 2013 World Health Organization guidelines). Results: Overall, 115 patients were included, 80 (70%) were men and 35 (30%) were women, with a median age of 32 years (range, 15-77 years). Of the 115 patients with ES, 85 were treated with anthracycline-based regimens, 41 with gemcitabine-based regimens, and 18 with pazopanib. Twenty-four received more than 1 treatment. Median follow-up was 34 months. Response rate for anthracycline-based regimens was 22%, with a median PFS of 6 months. One complete response (CR) was reported. A trend toward a higher response rate was noticed in morphological proximal type (26%) vs classic type (19%) and in proximal vs distal primary site (26% vs 18%). The response rate for gemcitabine-based regimens was 27%, with 2 CR and a median PFS of 4 months. In this group, a trend toward a higher response rate was reported in classic vs proximal morphological type (30% vs 22%) and in distal vs proximal primary site (40% vs 14%). In the pazopanib group, no objective responses were seen, and median PFS was 3 months. Conclusions and Relevance: This is the largest retrospective series of systemic therapy in ES. We confirm a moderate activity of anthracycline-based and gemcitabine-based regimens in ES, with a similar response rate and PFS in both groups. The value of pazopanib was low. These data may serve as a benchmark for trials of novel agents in ES.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Sarcoma/drug therapy , Adolescent , Adult , Aged , Anthracyclines/administration & dosage , Deoxycytidine/administration & dosage , Deoxycytidine/analogs & derivatives , Female , Humans , Indazoles , Kaplan-Meier Estimate , Male , Middle Aged , Pyrimidines/administration & dosage , Remission Induction , Response Evaluation Criteria in Solid Tumors , Retrospective Studies , Sulfonamides/administration & dosage , Young Adult , GemcitabineABSTRACT
BACKGROUND: Previous trials from our group suggested an overall survival benefit with five cycles of adjuvant full-dose epirubicin plus ifosfamide in localised high-risk soft-tissue sarcoma of the extremities or trunk wall, and no difference in overall survival benefit between three cycles versus five cycles of the same neoadjuvant regimen. We aimed to show the superiority of the neoadjuvant administration of histotype-tailored regimen to standard chemotherapy. METHODS: For this international, open-label, randomised, controlled, phase 3, multicentre trial, patients were enrolled from 32 hospitals in Italy, Spain, France, and Poland. Eligible patients were aged 18 years or older with localised, high-risk (high malignancy grade, 5 cm or longer in diameter, and deeply located according to the investing fascia), soft-tissue sarcoma of the extremities or trunk wall and belonging to one of five histological subtypes: high-grade myxoid liposarcoma, leiomyosarcoma, synovial sarcoma, malignant peripheral nerve sheath tumour, and undifferentiated pleomorphic sarcoma. Patients were randomly assigned (1:1) to receive three cycles of full-dose standard chemotherapy (epirubicin 60 mg/m2 per day [short infusion, days 1 and 2] plus ifosfamide 3 g/m2 per day [days 1, 2, and 3], repeated every 21 days) or histotype-tailored chemotherapy: for high-grade myxoid liposarcoma, trabectedin 1·3 mg/m2 via 24-h continuous infusion, repeated every 21 days; for leiomyosarcoma, gemcitabine 1800 mg/m2 on day 1 intravenously over 180 min plus dacarbazine 500 mg/m2 on day 1 intravenously over 20 min, repeated every 14 days; for synovial sarcoma, high-dose ifosfamide 14 g/m2, given over 14 days via an external infusion pump, every 28 days; for malignant peripheral nerve sheath tumour, intravenous etoposide 150 mg/m2 per day (days 1, 2, and 3) plus intravenous ifosfamide 3 g/m2 per day (days 1, 2, and 3), repeated every 21 days; and for undifferentiated pleomorphic sarcoma, gemcitabine 900 mg/m2 on days 1 and 8 intravenously over 90 min plus docetaxel 75 mg/m2 on day 8 intravenously over 1 h, repeated every 21 days. Randomisation was stratified by administration of preoperative radiotherapy and by country of enrolment. Computer-generated random lists were prepared by use of permuted balanced blocks of size 4 and 6 in random sequence. An internet-based randomisation system ensured concealment of the treatment assignment until the patient had been registered into the system. No masking of treatment assignments was done. The primary endpoint was disease-free survival. The primary and safety analyses were planned in the intention-to-treat population. We did yearly futility analyses on an intention-to-treat basis. The study was registered with ClinicalTrials.gov, number NCT01710176, and with the European Union Drug Regulating Authorities Clinical Trials, number EUDRACT 2010-023484-17, and is closed to patient entry. FINDINGS: Between May 19, 2011, and May 13, 2016, 287 patients were randomly assigned to a group (145 to standard chemotherapy and 142 to histotype-tailored chemotherapy), all of whom, except one patient assigned to standard chemotherapy, were included in the efficacy analysis (97 [34%] with undifferentiated pleomorphic sarcoma; 64 [22%] with high-grade myxoid liposarcoma; 70 [24%] with synovial sarcoma; 27 [9%] with malignant peripheral nerve sheath tumour; and 28 [10%] with leiomyosarcoma). At the third futility analysis, with a median follow-up of 12·3 months (IQR 2·75-28·20), the projected disease-free survival at 46 months was 62% (95% CI 48-77) in the standard chemotherapy group and 38% (22-55) in the histotype-tailored chemotherapy group (stratified log-rank p=0·004; hazard ratio 2·00, 95% CI 1·22-3·26; p=0·006). The most common grade 3 or higher adverse events in the standard chemotherapy group (n=125) were neutropenia (107 [86%]), anaemia (24 [19%]), and thrombocytopenia (21 [17%]); the most common grade 3 or higher adverse event in the histotype-tailored chemotherapy group (n=114) was neutropenia (30 [26%]). No treatment-related deaths were reported in both groups. In agreement with the Independent Data Monitoring Committee, the study was closed to patient entry after the third futility analysis. INTERPRETATION: In a population of patients with high-risk soft-tissue sarcoma, we did not show any benefit of a neoadjuvant histotype-tailored chemotherapy regimen over the standard chemotherapy regimen. The benefit seen with the standard chemotherapy regimen suggests that this benefit might be the added value of neoadjuvant chemotherapy itself in patients with high-risk soft-tissue sarcoma. FUNDING: European Union grant (Eurosarc FP7 278472).
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Neurilemmoma/therapy , Sarcoma/pathology , Sarcoma/therapy , Soft Tissue Neoplasms/pathology , Soft Tissue Neoplasms/therapy , Abdominal Wall , Adolescent , Adult , Aged , Anemia/chemically induced , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Back , Chemotherapy, Adjuvant/methods , Child , Dacarbazine/administration & dosage , Deoxycytidine/administration & dosage , Deoxycytidine/analogs & derivatives , Dioxoles/administration & dosage , Disease-Free Survival , Docetaxel , Epirubicin/administration & dosage , Etoposide/administration & dosage , Extremities , Humans , Ifosfamide/administration & dosage , Leiomyosarcoma/therapy , Liposarcoma, Myxoid/therapy , Middle Aged , Neoadjuvant Therapy/methods , Neutropenia/chemically induced , Risk Factors , Sarcoma, Synovial/therapy , Taxoids/administration & dosage , Tetrahydroisoquinolines/administration & dosage , Thoracic Wall , Thrombocytopenia/chemically induced , Trabectedin , Young Adult , GemcitabineABSTRACT
BACKGROUND: Adjuvant imatinib mesylate prolongs recurrence-free survival (RFS) after resection of localised primary gastrointestinal stromal tumours (GIST). We aimed to develop a nomogram to predict RFS after surgery in the absence of adjuvant therapy to help guide patient selection for adjuvant imatinib therapy. METHODS: A nomogram to predict RFS based on tumour size (cm), location (stomach, small intestine, colon/rectum, or other), and mitotic index (<5 or > or =5 mitoses per 50 high-power fields) was developed from 127 patients treated at Memorial Sloan-Kettering Cancer Center (MSKCC), New York, NY, USA. The nomogram was tested in patients from the Spanish Group for Research on Sarcomas (GEIS; n=212) and the Mayo Clinic, Rochester, MN, USA (Mayo; n=148). The nomogram was assessed by calculating concordance probabilities and testing calibration of predicted RFS with observed RFS. Concordance probabilities were also compared with those of three commonly used staging systems. FINDINGS: The nomogram had a concordance probability of 0.78 (SE 0.02) in the MSKCC dataset, and 0.76 (0.03) and 0.80 (0.02) in the validation cohorts. Nomogram predictions were well calibrated. Inclusion of tyrosine kinase mutation status in the nomogram did not improve its discriminatory ability. Concordance probabilities of the nomogram were better than those of the two NIH staging systems (0.76 [0.03] vs 0.70 [0.04, p=0.04] and 0.66 [0.04, p=0.01] in the GEIS validation cohort; 0.80 [0.02] vs 0.74 [0.02, p=0.04] and 0.78 [0.02, p=0.05] in the Mayo cohort) and similar to those of the AFIP-Miettinen staging system (0.76 [0.03] vs 0.73 [0.004, p=0.28] in the GEIS cohort; 0.80 [0.02] vs 0.76 [0.003, p=0.09] in the Mayo cohort). Nomogram predictions of RFS seemed better calibrated than predictions made with the AFIP-Miettinen system. INTERPRETATION: The nomogram accurately predicts RFS after resection of localised primary GIST and could be used to select patients for adjuvant imatinib therapy.