Assessment of resection margins in bone sarcoma treated by neoadjuvant chemotherapy: Literature review and guidelines of the bone group (GROUPOS) of the French sarcoma group and bone tumor study group (GSF-GETO/RESOS)

BACKGROUND

Standardized reports are essential to meeting the bone sarcoma reference center certification requirements of the French National Cancer Institute (INCa). The usual classifications of the Musculoskeletal Tumor Society (MSTS), the American Joint Committee on Cancer (AJCC/IUCC) TNM R classification and the American College of Pathologists, are inexact inasmuch as they fail to include chemotherapy impact on tumor cells in assessing surgical margins. This leads to inconsistent interpretation by teams managing bone sarcoma. The present literature analysis sought to assess the limitations of existing classifications for purposes of standardized reporting of the management of surgical specimens from patients with osteosarcoma or Ewing sarcoma receiving neoadjuvant chemotherapy, by addressing the following questions: 1) What is the prognostic value of margins and chemotherapy response in the classifications? 2) What are the histologic changes induced by chemotherapy, with what impact on interpretation of margins?

METHOD

A PubMed literature analysis was performed, targeting the prognostic value of resection margin assessment, in September 2018. French bone pathology group (Groupe français des pathologistes osseux) and international guidelines on bone specimen management were referred to so as select items for a standardized report. Eight of the 523 articles retrieved met the study eligibility criteria.

RESULTS

Minimal distance between tumor and surgical margin, with a>2mm threshold, seemed to be the optimal parameter for predicting local recurrence. Good chemotherapy response and appendicular skeletal location were associated with lower risk of local recurrence. None of the available classifications take into account the microscopic changes induced by chemotherapy in interpreting resection margins.

DISCUSSION

To standardize practice, GROUPOS developed a standardized report for bone sarcoma specimens, considering the histopathologic changes in the tumor after neoadjuvant chemotherapy. The TNM R system was adapted and a threshold of>2mm was chosen as an acceptable limit to qualify surgical resection as safe (R0). R1 status (≤2mm) was subdivided into subgroups a, b and c, to include margin measurement in relation to the post-chemotherapy scar: R1a, resection within the scar; R1b, resection in healthy tissue,≤2mm from the scar and/or residual viable cells; and R1c, resection within the lesion in contact with viable cells or within coagulation necrosis areas. The GROUPOS members drew up this standardized report so as to ensure a common language, improving bone sarcoma management in specialized centers. Reliable data can thus be established for national and international multicenter studies.

LEVEL OF EVIDENCE

IV.

Metabolic profile and neoadjuvant chemotherapy sensitivity in high-grade bone sarcoma

e22506

Background: Neoadjuvant chemotherapy with intercalated surgery is the standard of care for resectable high-grade bone sarcoma (BS) but identification of biomarkers for chemosensitivity prediction is still needed. Methods: We recruited 121 pts with new primary localized or metastatic BS, measured fasting blood glucose and insulin, body mass index (BMI). The HOMA-IR (Homeostasis Model Assessment) score ((Glucose (mmol/l) x Insulin) / 22.5), which has been proven to reliably detect insulin resistance was calculated, and patients with HOMA-IR > 2.6 were considered as insulin resistant (IR). We collected characteristics usually associated with insulin resistance (IR): age, obesity, diabetes, dyslipidemia and hypertension. Results: Out of 121 pts, 48 (40%) were IR: HOMA-IR > 2.6. Thirty IR patients (62%) had no cardiovascular risk factor. In univariate analysis, IR was associated with obesity (BMI > 30 kg/m2)(23% vs 3%, p = 0.0013), but not with age (median 38.4 vs 43.3 years, p = 0.15). IR was more prevalent in Ewing sarcoma (12/21; 57%) and chondrosarcoma (7/13; 54%) followed by osteosarcoma (25/61; 41%) and other rare bone sarcomas (4/26; 15.3%)(p = 0.037). After preoperative chemotherapy and surgery of Ewing tumor and osteosarcoma, pathologic tumor necrosis was higher in IR pts (85.8 vs 69.3%, p = 0.012). Using multivariate linear regression models, IR was independently associated with pathologic tumor necrosis (p = 0.042) but not with obesity (p = 0.55). Conclusions: Our results suggest that tumor-induced metabolic profile may help to discriminate best candidates for preoperative chemotherapy in high-grade bone sarcomas. Further studies are needed to confirm and explain these results.

Improved local relapse-free and overall survival with secondary surgery after a first R1 or R2 resection in soft tissue sarcoma (STS) of the limbs or trunk wall: An analysis 10,931 patients (pts) in NETSARC

11056

Background: We previously reported that secondary resection (2Surg) improved local relapse free (LRFS) but not overall survival (OS) in a retrospective series of pts with localized STS after unplanned 1st excision. Here we investigated the impact of 2Surg specifically after a first R1 or R2 resection in the 10931 pts with STS of the limb or trunk wall included in the nationwide NETSARC database from 2010 to 2017. Methods: NETSARC (netsarc.org) is a network of 26 reference sarcoma centers with specialized multidisciplinary tumor boards (MDT), funded by the French NCI (INCa). Since 2010, presentation to an MDTB and second pathological review are mandatory for sarcoma pts. Statistics were performed with SPSS23.0. LRFS, metastasis-free survival (MFS), OS compared with the logrank test. Results: The series included 5598 (51.2%) males. Median age was 56.7. Tumor sites: 5295 (49.4%) lower limb, 3670 (33.6%) trunk wall. 1966 (18.0%) upper limb. As previously reported in the entire series, local RFS (LRFS) and RFS (p<0.001), but not OS, were superior for pts presented to a NETSARC MDT (NMDT), or operated in a NETSARC center (N=4417, 41%). LRFS & OS were best for pts presented to a NMDT AND operated in NETSARC centers; while the worst LRFS & OS were observed in pts presented in a NMDT but not operated there (p<0.001). Among the 2081 pts with a first R1 resection in whom 2Surg was documented, 1047 (50.3%) were reoperated. R1 reoperated pts had a superior LRFS, metastatic free survival (MFS) and OS (p<0.001). LRFS (p<0.001), MFS (p=0.05) and OS (p<0.001) were superior after 2Surg only in pts operated 1st outside a Netsarc center. There were 823 pts with a first surgery with R2 resection in whom 2Surg was documented: 619 (75.2%) were reoperated. R2 reoperated patients had a superior LRFS and OS (p=0.01). MFS was not different. LRFS (p<0.001) & OS (p<0.001) were superior after 2Surg only in pts operated 1st outside a Netsarc center. 2028 (%) pts had 2Surg. Pts for whom 2Surg was in a NetSARC center had a superior LRFS (p<0.001) and OS (p=0.01) when operated first outside a NETSARC center. Conclusions: In this nationwide series of limb or trunk wall STS, 2Surg after a R1 or R2 primary excision improves LRFS & OS when the pts were operated 1st outside a reference center. 2Surg in a NETSARC center was associated with a better LRFS and OS.

Sarcomas in patients over 90: Natural history and treatment-A nationwide study over 6 years

Soft tissue sarcomas (STS) are rare tumors accounting for less than 1% of human cancers. While the highest incidence of sarcomas is observed in elderly, this population is often excluded or poorly represented in clinical trials. The present study reports on clinicopathological presentation, and outcome of sarcoma patients over 90 recorded in the Netsarc.org French national database. NETSARC (netsarc.org) is a network of 26 reference sarcoma centers with specialized multidisciplinary tumor board (MDTB), funded by the French National Cancer Institute to improve the outcome of sarcoma patients. Since 2010, presentation to an MDTB, second pathological review, and collection of sarcoma patient characteristics and follow‐up are collected in a database Information of patients registered from January 1, 2010, to December 31, 2016, in NETSARC were collected, analyzed and compared to the younger population. Patients with sarcomas aged >90 have almost exclusively sarcomas with complex genomics (92.0% vs. 66.3%), are less frequently metastatic (5.3% vs. 14·7%) at diagnosis, have more often superficial tumors (39.8% vs. 14.7%), as well as limbs and head and neck sites (75.2% vs. 38.7%) (all p < 0.001). Optimal diagnostic procedures and surgery were less frequently performed in patients over 90 (p < 0.001). These patients were less frequently operated in NETSARC centers, as compared to those of younger age groups including aged 80–90. However, local relapse‐free survival, metastatic relapse‐free survival and relapse‐free survival were not significantly different from those of younger patients, in the whole cohort, as well as in the subgroup of operated patients. As expected overall survival was worse in patients over 90 (p < 0.001). Patients over 90 who were not operated had worse overall survival than younger patients (9.9 vs. 27.3 months, p < 0.001). Patients with STS diagnosed after 90 have distinct clinicopathological features, but comparable relapse‐free survival, unless clinical practice guidelines recommendations are not applied. Standard management should be proposed to these patients if oncogeriatric status allows.

What's new?

While the highest incidence of soft‐tissue sarcoma (STS) is observed in the elderly, this population is often excluded or poorly represented in clinical trials. Therefore, little is known about the characteristics, treatment, and outcomes of STS in these patients. In this study, the authors analyzed numerous clinical characteristics of patients with sarcoma diagnosed at age 91 or older. They conclude that standard STS management and clinical practice guidelines should be followed for these patients if possible.

Biological secondary contributors to osteoporosis in fractured patients, is an early systematic assay relevant?

OBJECTIVE

To evaluate the prevalence of biological abnormalities leading to secondary osteoporosis in recently fractured patients.

METHODS

Adults older than 50, hospitalized for a non-vertebral fracture from July 2015 to October 2016, were assessed for bone fragility contributors in the orthopedics department. Bone mineral density (BMD) measurements and vertebral fracture assessment (VFA) were performed within 3 months. We assessed the prevalence of biological abnormalities in all the patients with recent fracture and in subgroups.

RESULTS

Among 439 hospitalized patients for non-vertebral low trauma fracture, 372 had biological tests (285 women, mean age 77.5 ± 13 years) and 353 (94.6%) had at least ≥ 1 biological abnormality, most frequently vitamin D insufficiency (< 75 nmol/L) (80%). Hypercalcemia was found in 22 (7.7%) patients, explained by possible primary hyperparathyroidism in 6 cases, and by the other causes of hypercalcemia including postoperative low albumin. A high PTH level was observed in 64 (20.8%) patients. We found 3 monoclonal bands. Results were similar in patients with and without vertebral fracture or osteoporosis. Finally, many biological abnormalities can be explained by the postoperative context (low TSH, hypogammaglobulinemia, low albumin, low alkaline phosphatase) and need a control.

CONCLUSION

This study performed in patient with recent low trauma non-vertebral fractures showed that 94.6% of patients had at least one contributor to bone fragility, which was the vitamin D insufficiency in most of cases. We found a high proportion of biological abnormalities which require additional explorations but most of them can be explained by the postoperative context.

Osteosarcoma after the age of fifty: A clinicopathological study

INTRODUCTION

Osteosarcoma, a primary malignant bone tumor, has a well-recognised double peak of incidence in early adolescence and after 50 years. This study investigates the clinical features and prognostic factors of patients older than 50 years with osteosarcoma.

MATERIEL AND METHODS

From January 2000 to December 2012, in one bone tumor reference center, 32 patients aged more than 50 years at the diagnosis (mean age: 62.4 years (50-85), sex ratio: 13 males, 19 females) diagnosed with osteosarcoma were included. Patients younger than 50 years at diagnosis or with a non-histologically proved osteosarcoma were excluded. For each patient, we registered medical history, tumor location, systemic and local extension, treatment, and survival.

RESULTS

62% were located in the extremities and 28% in the axial skeleton. 6 were secondary sarcomas. Mean delay between first symptoms and biopsy was 7.4 months (range from 0 to 28 months). Ten patients had a systemic osteosarcoma with one or more pulmonary metastases. Six patients were treated with palliative care (18.8%). Eighteen patients received neodajuvant chemotherapy, sixteen of them received postoperative chemotherapy. Twenty-five patients had surgery. Postoperative complications were reported in eight cases (25%). Overall survival for all 31 patients was 25% at 5 years and 6.2% at 10 years. Survival without metastases was 15.6% at 5 years and nil at 10 years. Median survival time for the 22 localised osteosarcoma patients was 4 years (0.9-12.6) versus 1.2 years (0.3-12.3) for the 10 systemic osteosarcoma patients (p = 0.01).

CONCLUSION

Metastases at diagnosis, age, axial location are worse prognostic for survival.

Patients with Revision Modern Megaprostheses of the Distal Femur Have Improved Disease-Specific and Health-Related Outcomes Compared to Those with Primary Replacements

We asked whether there would be any difference between primary and revision modern cemented fixed hinge megaprosthesis of the distal femur in function and activity-related outcomes following treatment of a bone tumor. An identical custom-made fixed hinge cemented megaprosthesis with a hydroxyapatite collar was used in all cases. The main outcomes were joint-specific function, disease-specific activity, and health-related quality of life. Implant survival was also evaluated. Patients in the revision group performed slightly better than patients in the primary group on disease-specific (Toronto Extremity Salvage Score, p = 0.033; Musculoskeletal Tumor Society, p = 0.072) and health-related outcomes (Short Form 36 [SF-36] physical component, p = 0.085; SF-36 mental component, p = 0.069) but not on joint-specific outcomes (Knee Society Score, p = 0.94). The cumulative probabilities of revision for any reason were 14.5% (7-25%) at 5 years with no statistically significant difference between primary and revision procedures (p = 0.77). In conclusion, patients undergoing a revision have similar joint-specific functional outcome but improved disease-specific and health-related outcomes. Implant survival are similar between groups.

Higher complications after previous external beam radiation for extremity soft-tissue sarcoma in the surgical treatment of a local recurrence: a comparative retrospective study of one hundred and three patients

PURPOSE

The use of adjuvant radiation in the treatment of soft-tissue sarcoma (STS) is equivocal in selected cases. Our objective was to compare the short-term outcomes in patients operated on for a local recurrence who had radiation for the primary tumour to those who were spared radiation.

METHODS

This was a retrospective study of 103 patients treated for a local recurrence: 48 (47%) with previous radiation and 55 (53%) without. Our primary outcome criterion was to identify the differences in the local treatment provided. Secondary outcomes were the cumulative incidence of a surgical site infection/wound complication (SSI/WC), variables associated with SSI/WC, and local recurrence.

RESULTS

Amputation and the incidence of re-operation were significantly more frequent in patients who received previous radiation compared to patients without previous radiation (27% vs 9%, p = 0.02, for amputation; 26% vs 36% at 2 years for SSI/WC, p = 0.049). Multivariable regression models found previous radiation (p = 0.049), arteriopathy (p = 0.012), location at lower limb (p = 0.09), and use of a flap (0.0048) associated with the risk of SSI/WC.

CONCLUSIONS

Previous radiation is associated with an increased risk of amputation and reoperation for SSI/WC when treating a local recurrence. This information should be accounted for when deciding for the use of radiation.

Can a Single-Use and Patient-Specific Instrumentation Be Reliably Used in Primary Total Knee Arthroplasty? A Multicenter Controlled Study

BACKGROUND

The aim of this controlled multicenter study is to evaluate the clinical and radiologic outcomes of primary total knee arthroplasty (TKA) using single-use fully disposable and patient-specific cutting guides (SU) and compare the results to those obtained with traditional patient-specific cutting guides (PSI) vs conventional instrumentation (CI).

METHODS

Seventy consecutive patients had their TKA performed using SU. They were compared to 140 historical patients requiring TKA that were randomized to have the procedure performed using PSI vs CI. The primary measure outcome was mechanical axis as measured on a standing long-leg radiograph using the hip-knee-ankle angle. Secondary outcome measures were Knee Society and Oxford knee scores, operative time, need for postoperative transfusion, and length of hospital stay.

RESULTS

The mean hip-knee-ankle value was 179.8° (standard deviation [SD] 3.1°), 179.2° (SD 2.9°), and 178.3° (SD 2.5°) in the CI, PSI and SU groups, respectively (P = .0082). Outliers were identified in 16 of 65 (24.6%), 15 of 67 (22.4%), and 14 of 70 (20.0%) knees in the CI, PSI, and SU group, respectively (P = .81). There was no significant difference in the clinical results (P = .29 and .19, respectively). Operative time, number of unit transfusion, and length of hospital stay were not significantly different between the 3 groups (P = .45, .31, and 0.98, respectively).

CONCLUSION

The use of an SU in TKA provided similar clinical and radiologic results to those obtained with traditional PSI and CI. The potential economic advantages of single-use instrumentation in primary TKA require further investigation.

The indications and donor-site morbidity of tibial cortical strut autografts in the management of defects in long bones

Aims

The primary aim of this study was to determine the morbidity of a tibial strut autograft and characterize the rate of bony union following its use.

Patients and Methods

We retrospectively assessed a series of 104 patients from a single centre who were treated with a tibial strut autograft of > 5 cm in length. A total of 30 had a segmental reconstruction with continuity of bone, 27 had a segmental reconstruction without continuity of bone, 29 had an arthrodesis and 18 had a nonunion. Donor-site morbidity was defined as any event that required a modification of the postoperative management. Union was assessed clinically and radiologically at a median of 36 months (IQR, 14 to 74).

Results

Donor-site morbidity occurred in four patients (4%; 95% confidence interval (CI) 1 to 10). One patient had a stress fracture of the tibia, which healed with a varus deformity, requiring an osteotomy. Two patients required evacuation of a haematoma and one developed anterior compartment syndrome which required fasciotomies. The cumulative probability of union was 90% (95% CI 80 to 96) at five years. The type of reconstruction (p = 0.018), continuity of bone (p = 0.006) and length of tibial graft (p = 0.037) were associated with the time to union.

Conclusion

The tibial strut autograft has a low risk of morbidity and provides adequate bone stock for treating various defects of long bones. Cite this article: Bone Joint J 2018;100-B:667-74.

BRCA2 Loss-of-Function and High Sensitivity to Cisplatin-Based Chemotherapy in a Patient With a Pleomorphic Soft Tissue Sarcoma: Effect of Genomic Medicine

We report the case of a patient with a BRCA2 germline mutation who developed a localized pleomorphic soft tissue sarcoma of the leg with poor prognostic features. BRCA2 germline mutations were not previously reported to be associated with pleomorphic sarcoma. BRCA2 loss-of-heterozygosity was found in the tumor, resulting in a complete BRCA2 loss-of-function. BRCA2 deficiency is associated with sensitivity to cisplatin-based chemotherapy in breast and ovarian cancer patients. We used a cisplatin-based chemotherapy. A rapid major partial response was obtained, which allowed a curative and conservative surgical resection of the sarcoma followed by adjuvant irradiation. This case illustrates that sarcoma patients may present unexpected but targetable genetic abnormalities and that BRCA2 loss-of-function may be targetable in sarcoma as it is associated with enhanced sensitivity to cisplatin. Our observation emphasizes the input of genomic medicine in clinical practice, its importance for treatment decisions, and the overlap between constitutional and somatic genetics.

Proximal femoral osteosarcoma: Diagnostic challenges translate into delayed and inappropriate management

BACKGROUND

The proximal femuris is an uncommon site of osteosarcoma. The unusual manifestations at this site may lead to diagnostic and therapeutic mistakes. We therefore performed a retrospective study to estimate the proportions of patients with imaging study findings and/or clinical manifestations typical for osteosarcoma and/or inappropriate treatment decisions.

HYPOTHESIS

Proximal femoral osteosarcoma often produces atypical clinical and radiological presentations.

MATERIAL AND METHODS

Consecutive patients who underwent surgery at our center to treat proximal femoral osteosarcoma were included. For each patient, we collected the epidemiological characteristics, clinical symptoms, imaging study findings, treatment, and tumor outcome. Proportions were computed with their confidence intervals.

RESULTS

Twelve patients had surgery for proximal femoral osteosarcoma between 1986 and 2015. Imaging findings were typical in 1 (8%) patient; they consisted of ill-defined osteolysis in 11/12 (92%) patients, a periosteal reaction in 1/12 (8%) patient, soft tissue involvement in 7/12 (58%) patients, and immature osteoid matrix in 11/12 (92%) patients. No patient had the typical combination of pain with a soft tissue swelling. Management was inappropriate in 2/12 (17%) patients, who did not undergo all the recommended imaging studies before surgery and were treated in another center before the correct diagnosis was established. At last follow-up, 4 patients had died (after a mean of 7 years) and 8 were alive (after a mean of 4 years).

CONCLUSION

Proximal femoral osteosarcoma is uncommon and rarely produces the typical clinical and imaging study findings. The atypical presentation often results in diagnostic errors and inappropriate treatments. Ill-defined osteolysis on standard radiographs should prompt computed tomography or magnetic resonance imaging of the proximal femur. Treatment in a specialized center is imperative.

LEVEL OF EVIDENCE

IV, retrospective study.

Improved survival using specialized multidisciplinary board in sarcoma patients

BACKGROUND

Sarcomas are rare but aggressive diseases. Specialized multidisciplinary management is not implemented for all patients in most countries. We investigated the impact of a multidisciplinary tumor board (MDTB) presentation before treatment in a nationwide study over 5 years.

PATIENTS AND METHODS

NETSARC (netsarc.org) is a network of 26 reference sarcoma centers with specialized MDTB, funded by the French National Cancer Institute to improve the outcome of sarcoma patients. Since 2010, presentation to an MDTB and second pathological review are mandatory for sarcoma patients in France. Patients' characteristics and follow-up are collected in a database regularly monitored and updated. The management and survival of patients presented to these MDTB before versus after initial treatment were analyzed.

RESULTS

Out of the 12 528 patients aged ≥15 years, with a first diagnosis of soft tissue and visceral sarcoma obtained between 1 January 2010 and 31 December 2014, 5281 (42.2%) and 7247 (57.8%) were presented to the MDTB before and after the initiation of treatment, respectively. The former group had generally worse prognostic characteristics. Presentation to a MDTB before treatment was associated with a better compliance to clinical practice guidelines, for example, biopsy before surgery, imaging, quality of initial surgery, and less reoperations (all P < 0.001). Local relapse-free survival and relapse-free survival were significantly better in patients presented to a MDTB before initiation of treatment, both in univariate and multivariate analysis.

CONCLUSION

The compliance to clinical practice guidelines and relapse-free survival of sarcoma patients are significantly better when the initial treatment is guided by a pre-therapeutic specialized MDTB.

Impact of Sequential Culture Results on Diagnosis and De-Escalation of the Antibiotic Regimen in Joint and Bone Infections

BACKGROUND

According to existing guidelines, orthopedic specimens collected in joint and bone infections (JBI) in our institution are cultured on several media sets and incubated for two, seven, and 14 days. The optimal timing for de-escalation of the first-line antibiotic combination according to the culture results needs to be defined.

METHODS

Single-center, retrospective analysis of all adult patients with a first documented episode of JBI between May 2012 and April 2013.

RESULTS

Ninety patients were included, 51 males (57%), median age 58 y (range 18-87 y), with prosthesis infection in 62 cases (69%). Rapidly growing pathogens (Staphylococcus aureus [n = 36] and Enterobacteriaceae [n = 12]) usually were diagnosed within two days, whereas coagulase-negative staphylococci (n = 25) and Propionibacterium acnes (n = 13) generally were identified after seven days (p < 10^-5). Positive culture results at day 2 fit with definitive microbiological diagnosis in 95% of cases, and prolonged incubation led to the identification of additional micro-organisms in only four of 76 patients (5%) with day-2-positive cultures. Conversely, for those with negative two-day culture (n = 14), the seven-day culture allowed identification of less virulent pathogens in eight cases (57%).

CONCLUSIONS

Our results suggest that, in JBI, de-escalation of the empirical antibiotic regimen can be based on micro-organisms identified on the two-day culture set. The impact of such a strategy on clinical outcomes, antibiotic consumption, and costs needs to be assessed in larger studies.

Is it safe to preserve the deltoid when resecting the proximal humerus for a primary malignant bone tumour? A comparative study

AIMS

Resection of the proximal humerus for the primary malignant bone tumour sometimes requires en bloc resection of the deltoid. However, there is no information in the literature which helps a surgeon decide whether to preserve the deltoid or not. The aim of this study was to determine whether retaining the deltoid at the time of resection would increase the rate of local recurrence. We also sought to identify the variables that persuade expert surgeons to choose a deltoid sparing rather than deltoid resecting procedure.

PATIENTS AND METHODS

We reviewed 45 patients who had undergone resection of a primary malignant tumour of the proximal humerus. There were 29 in the deltoid sparing group and 16 in the deltoid resecting group. Imaging studies were reviewed to assess tumour extension and soft-tissue involvement. The presence of a fat rim separating the tumour from the deltoid on MRI was particularly noted. The cumulative probability of local recurrence was calculated in a competing risk scenario.

RESULTS

There was no significant difference (adjusted p = 0.89) in the cumulative probability of local recurrence between the deltoid sparing (7%, 95% confidence interval (CI) 1 to 20) and the deltoid resecting group (26%, 95% CI 8 to 50). Patients were more likely to be selected for a deltoid sparing procedure if they presented with a small tumour (p = 0.0064) with less bone involvement (p = 0.032) and a continuous fat rim on MRI (p = 0.002) and if the axillary nerve could be identified (p = 0.037).

CONCLUSION

A deltoid sparing procedure can provide good local control after resection of the proximal humerus for a primary malignant bone tumour. A smaller tumour, the presence of a continuous fat rim and the identification of the axillary nerve on pre-operative MRI will persuade surgeons to opt for a deltoid resecting procedure. Cite this article: Bone Joint J 2017;99-B:1244-9.

Using Bayesian statistics to estimate the likelihood a new trial will demonstrate the efficacy of a new treatment

Background

The common frequentist approach is limited in providing investigators with appropriate measures for conducting a new trial. To answer such important questions and one has to look at Bayesian statistics.

Methods

As a worked example, we conducted a Bayesian cumulative meta-analysis to summarize the benefit of patient-specific instrumentation on the alignment of total knee replacement from previously published evidence. Data were sourced from Medline, Embase, and Cochrane databases. All randomised controlled comparisons of the effect of patient-specific instrumentation on the coronal alignment of total knee replacement were included. The main outcome was the risk difference measured by the proportion of failures in the control group minus the proportion of failures in the experimental group. Through Bayesian statistics, we estimated cumulatively over publication time of the trial results: the posterior probabilities that the risk difference was more than 5 and 10%; the posterior probabilities that given the results of all previous published trials an additional fictive trial would achieve a risk difference of at least 5%; and the predictive probabilities that observed failure rate differ from 5% across arms.

Results

Thirteen trials were identified including 1092 patients, 554 in the experimental group and 538 in the control group. The cumulative mean risk difference was 0.5% (95% CrI: −5.7%; +4.5%). The posterior probabilities that the risk difference be superior to 5 and 10% was less than 5% after trial #4 and trial #2 respectively. The predictive probability that the difference in failure rates was at least 5% dropped from 45% after the first trial down to 11% after the 13th. Last, only unrealistic trial design parameters could change the overall evidence accumulated to date.

Conclusions

Bayesian probabilities are readily understandable when discussing the relevance of performing a new trial. It provides investigators the current probability that an experimental treatment be superior to a reference treatment. In case a trial is designed, it also provides the predictive probability that this new trial will reach the targeted risk difference in failure rates.

Trial registration

CRD42015024176.

Electronic supplementary material

The online version of this article (doi:10.1186/s12874-017-0401-x) contains supplementary material, which is available to authorized users.

Brain and skull base MRI findings in patients with Ollier-Maffucci disease: A series of 12 patient-cases

OBJECTIVES

To estimate the prevalence rate of silent cranial and intracranial lesions in a series of Ollier-Maffucci patients.

PATIENTS AND METHODS

Cerebral MRI was routinely performed in Ollier-Maffucci patients followed-up in our tertiary centers. Patients with previous history of skull base or intracranial tumors were excluded from the study. Clinical and radiological datas were retrospectively collected. The occurrence rate and nature of abnormal cerebral MRIs were determined.

RESULTS

Twelve patients were included. A glioma-looking lesion was found in one patient (8%), while skull base lesions were evidenced in 3 others (25%). A regular MRI follow-up was recommended for each patient, with a time interval varying between 1year and 3years depending on the likelihood of tumoral evolutivity, as infered from the MRI findings.

CONCLUSION

All in all, the high rate of intracranial and skull base lesions with a malignant potential warrants to include cerebral MRI in the routine follow-up of Ollier-Maffucci patients.