Comparison of the outcome of conventional osteosarcoma at two specialist international orthopaedic oncology centres

Chemotherapy Regimens for Non-Metastatic Conventional Appendicular Osteosarcoma: A Literature Review Based on the Outcomes

Osteosarcoma is a rare condition with a complex treatment. Most protocols include neoadjuvant chemotherapy, surgery, and consolidation chemotherapy as the standard of treatment. However, the use of neoadjuvant chemotherapy lacks scientific evidence proving superiority in opposition to the use of isolated chemotherapy in an adjuvant regimen after surgery. We conducted a review for studies published in English between 1980 and 2020, using the MEDLINE/PubMed and Scopus electronic databases, to evaluate the outcomes when using neoadjuvant chemotherapy or adjuvant chemotherapy strategies in the treatment of non-metastatic appendicular osteosarcoma, as well as the toxicity associated with different chemotherapeutic regimens. Patients were divided into a neoadjuvant chemotherapy group (NAC) and adjuvant chemotherapy group (ACT), depending on the chemotherapy regimen used in association with surgery. A total of 1254 articles in English were screened by title and abstract, and 146 were pre-selected for full reading and analysis. A total of 24 assays matching the inclusion criteria were selected: 10 prospective and 14 retrospective studies. This review points to an absence of significative differences in outcomes, namely overall survival, disease-free survival/event-free survival rates, or toxicity, regarding neoadjuvant or single adjuvant chemotherapy strategies used in the treatment of appendicular non-metastatic osteosarcomas. However, there is a significative difference in population dimensions between the NAC and the ACT groups. Additionally, clinical presentation, tumor localization, tumor volume, or histological type were not considered, with these variables presenting the potential to influence these results. Despite these limitations, our findings should allow a re-thinking of our current practice and promote new opportunities to optimize treatment, always looking towards better survival and lower complications rates.

Ninety Percent or Greater Tumor Necrosis Is Associated With Survival and Social Determinants of Health in Patients With Osteosarcoma in the National Cancer Database

BACKGROUND

The histologic response of osteosarcoma to chemotherapy is commonly cited as a prognostic factor and typically graded as the percent necrosis of the tumor at the time of surgical resection. Few studies, to our knowledge, have examined the relationship of tumor necrosis relative to other factors. Existing studies are limited by prolonged enrollment periods or analysis of patient subsets without the strongest predictor of mortality: metastasis at diagnosis. Additionally, the definitive threshold value for a good histologic response is commonly set at more than 90% tumor necrosis with little evidence; some authors advocate other values.

QUESTION/PURPOSES

(1) Are there alternative cutoff values for a good response to chemotherapy in a large, national cohort of contemporarily treated patients with osteosarcoma? (2) How does the association of histologic response to survival in osteosarcoma compare with other clinicopathologic factors? (3) What patient and clinical factors are associated with the histologic response?

METHODS

We identified 2006 patients with osteosarcoma diagnosed between 2010 and 2015 in the National Cancer Database (NCDB), a registry that includes 70% of all new cancers diagnosed in the United States with 90% follow-up. Patients were excluded for missing documentation of percent tumor necrosis (21% [425 of 2006]) or if definitive resection was not performed (< 1% [1 of 2006]). A total of 1580 patients were included in the analysis, with a mean follow-up duration of 37 ± 22 months. A Kaplan-Meier survival analysis, stratified by the percent tumor necrosis after chemotherapy, was performed for the 5-year period. Other covariates examined were sex, race, socioeconomic score composite, insurance type, Charlson/Deyo score, distance from the hospital, and location (metropolitan, urban, or rural). Clinical and sociodemographic data including patient-identified race from the patient's medical record is input into the NCDB by certified registrars. The NCDB only allows coding of one primary race for each patient; thus, most of our patients were grouped as White or Black race and the remaining were grouped as Other for our analysis. A multiple Cox regression analysis was performed to evaluate the effect of percent necrosis compared with other demographic, clinicopathologic, and treatment effects on survival. Finally, a multiple logistic regression analysis was performed to assess demographic and clinicopathologic characteristics associated with percent necrosis.

RESULTS

Five-year overall survival for patients with histologic gradings of 90% to 94% necrosis (70% [95% confidence interval (CI) 60.6% to 79.7%) and 95% to 100% necrosis (74% [95% CI 68% to 80.3%) was not different between groups (p = 0.47). A comparison of histologic responses below 90% necrosis found no difference in survival between patients with decreasing histologic response (p > 0.05). Necrosis of less than 90% was associated with worse survival (HR 2.00 [95% CI 1.58 to 2.52]; p < 0.001 compared with more than 90% necrosis), and factors most associated with poor survival were metastasis (HR 2.85 [95% CI 2.27 to 3.59]; p < 0.001) and skip metastasis at the time of diagnosis (HR 2.52 [95% CI 1.64 to 3.88]; p < 0.001). On multivariate analysis, adjusting for demographic, clinicopathologic, and treatment factors, social determinants of health were negatively associated with percent necrosis of 90% or more, including uninsured status (OR 0.46 [95% CI 0.23 to 0.92]; p = 0.02 compared with private insurance) and lower socioeconomic status composite (OR for the lowest first and second quartiles were 0.63 [95% CI 0.44 to 0.90]; p = 0.01 and 0.70 [95% CI 0.50 to 0.96]; p = 0.03, respectively). Race other than White or Black (OR 0.61 [95% CI 0.40 to 0.94]; p = 0.02 compared with White race) was also negatively associated with percent necrosis of more than 90% after controlling for available covariates.

CONCLUSION

This study suggests that a cutoff of 90% necrosis provides the best prognostic value for patients with osteosarcoma undergoing chemotherapy. Other threshold values did not show different survival benefits. Sociodemographic factors were associated with histologic response less than 90%. These associations must be carefully understood not as cause and effect but likely demonstrating the effects of health disparities and access to care. Although we controlled for multiple variables in our analysis, broad variables such as race may have been associated with histologic response due to unaccounted confounders. Medical providers should be aware of these associations to ensure equitable access and delivery of care because access to care may be responsible for these associations. Future studies should examine potential drivers of this observation, such as a delay in presentation or deviation from standard of care practices.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Correlation between Prognostic Factors and the Histopathological Response to Neoadjuvant Chemotherapy in Osteosarcoma: A Retrospective Study

Background

Multimodality treatment, incorporating neoadjuvant chemotherapy and adjuvant chemotherapy, is the standard management plan for osteosarcoma that increases the overall survival (OS) rate. However, data regarding prognostic factors affecting the histopathological response following neoadjuvant chemotherapy is limited. Patients and Methods. We retrospectively reviewed patients diagnosed with osteosarcoma in our center between 2008 and 2018. We classified patient characteristics according to gender, age, tumor size, site and stage at diagnosis, site of metastasis, type of surgery, necrosis rate based on the Huvos grading system, and the number of neoadjuvant chemotherapy cycles. We divided response to neoadjuvant chemotherapy into poor responder for patients with Huvos grades 1 and 2 and good responder for patients with Huvos grades 3 and 4. We also documented patients' survival and follow-up information.

Results

We reviewed 64 patients within 5–65 years of age, dominated by men (62.5%). The distal femur (53.1%) was the most common site of osteosarcoma. Fifteen (23.4%) patients had a good response while 49 (76.6%) patients were poor responders to neoadjuvant chemotherapy based on the Huvos grading system. Based on multivariate analysis, gender (p = 0.012), age (p = 0.029), symptom duration (p = 0.004), and tumor enlargement after neoadjuvant chemotherapy (p < 0.001) were significantly associated with histopathological response. A scoring system was proposed integrating these significant variables (age > 20 years = 1 point, female gender = 1 point, symptom duration > 12 weeks = 1 point, and increased tumor size after neoadjuvant chemotherapy = 2 points). This scoring system divides patients into two groups with a total score of more than two predicting a poor responder to neoadjuvant chemotherapy.

Conclusions

Age, gender, symptoms duration, and tumor size after neoadjuvant chemotherapy are the prognostic features that affect the histopathological response to neoadjuvant chemotherapy in patients with osteosarcoma.

Treatment outcome of patients with chondroblastic osteosarcoma of the limbs and pelvis

AIMS

The aim of this study was to identify factors that determine outcomes of treatment for patients with chondroblastic osteosarcomas (COS) of the limbs and pelvis.

PATIENTS AND METHODS

The authors carried out a retrospective review of prospectively collected data from 256 patients diagnosed between 1979 and 2015. Of the 256 patients diagnosed with COS of the pelvis and the limbs, 147 patients (57%) were male and 109 patients (43%) were female. The mean age at presentation was 20 years (0 to 90).

RESULTS

In all, 82% of the patients had a poor response to chemotherapy, which was associated with the presence of a predominantly chondroblastic component (more than 50% of tumour volume). The incidence of local recurrence was 15%. Synchronous or metachronous metastasis was diagnosed in 60% of patients. Overall survival was 51% and 42% after five and ten years, respectively. Limb localization and wide surgical margins were associated with a lower risk of local recurrence after multivariable analysis, while the response to chemotherapy was not. Local recurrence, advanced patient age, pelvic tumours, and large volume negatively influenced survival. Resection of pulmonary metastases was associated with a survival benefit in the limited number of patients in whom this was undertaken.

CONCLUSION

COS demonstrates a poor response to chemotherapy and a high incidence of metastases. Wide resection is associated with improved local control and overall survival, while excision of pulmonary metastases is associated with improved survival in selected patients. Cite this article: Bone Joint J 2019;101-B:739-744.

Do Surgical Margins Affect Local Recurrence and Survival in Extremity, Nonmetastatic, High-grade Osteosarcoma?

BACKGROUND

Long-term survival for all patients with osteosarcoma using current aggressive adjuvant chemotherapy and surgical resection is between 60% and 70%. In patients who present with nonmetastatic, high-grade extremity osteosarcoma of bone, limb salvage surgery is favored, when appropriate, over amputation to preserve the limb, because limb salvage may lead to a superior quality of life compared with amputation. However, concern remains that in the attempt to preserve the limb, close or microscopically positive surgical margins may have an adverse effect on event-free survival.

QUESTIONS/PURPOSES

(1) Does a positive or close surgical margin increase the likelihood of a local recurrence? (2) Does a positive or close surgical margin adversely affect the development of metastatic disease? (3) What is the relationship of surgical margin on overall survival?

METHODS

With institutional review board approval, we retrospectively evaluated 241 patients treated at our institution between 1999 and 2011. Exclusion criteria included nonextremity locations, metastatic disease at initial presentation, low- or intermediate-grade osteosarcoma, treatment regimens that did not follow National Comprehensive Cancer Network (NCCN) guidelines, incomplete medical records, and any part of treatment performed outside of Moffitt Cancer Center or All Children's Hospital. Fifty-one patients were included in the final analysis, of whom 31 (61%) had followup data at a minimum of 2 years or whose clinical status was known but had died before 2 years of followup. Margin status was defined as (1) microscopically positive; (2) negative ≤ 1 mm; and (3) negative > 1 mm. Margin status, histologic response (tumor percent necrosis), type of osteosarcoma, type of surgery, presence of local recurrence, metastatic disease, and overall survival were recorded for each patient. The mean age was 22 years (range, 12-74 years) and the mean followup was 3 years (range, 0.1-14 years). Margin status was positive in 10% (five of 51), negative ≤ 1 mm 26% (13 of 51), and negative > 1 mm 65% (33 of 51).

RESULTS

Local recurrence was noted to be 14% (seven of 51) at 3.4 years. After controlling for relevant confounding variables, the presence of a positive margin compared with a negative margin > 1 mm was the only independent predictor of local recurrence (hazard ratio [HR], 8.006; 95% confidence interval [CI], 1.314-48.781; p = 0.0241). At a mean of 3.4 years, 29% (15 of 51) of the patients developed metastatic disease with no difference with the numbers available in the probability of developing metastatic disease among the three margin groups (p = 0.614). Overall survival at 3.8 years was 75% (38 of 51). After controlling for relevant confounding variables, we found that patients with positive margins were more likely to die from disease than those with negative margins (HR, 6.26; 95% CI, 1.50-26.14; p = 0.0119); no other independent predictors of survival were identified.

CONCLUSIONS

With the numbers of patients we had, we observed that patients with extremity, nonmetastatic, high-grade osteosarcoma who had positive margins showed a higher probability of local recurrence in comparison to those with negative surgical margins. Given that positive margins appear to be associated with poorer survival in patients with high-grade osteosarcoma of the extremities, surgeons should strive to achieve negative margins, but larger studies are needed to confirm these findings.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Prognostic Significance of Serum Alkaline Phosphatase Level in Osteosarcoma: A Meta-Analysis of Published Data

Background. Serum alkaline phosphatase (SALP) is commonly elevated in osteosarcoma patients. A number of studies have investigated the prognostic role of SALP level in patients with osteosarcoma but yielded inconsistent results. Method. Systematic computerized searches were performed in PubMed, Embase, and Web of Science databases for relevant original articles. The pooled hazard ratios (HRs) and relative risks (RRs) with corresponding confidence intervals (CIs) were calculated to assess the prognostic value of SALP level. Results. Finally, 21 studies comprising 3228 patients were included. Overall, the pooled HRs of SALP suggested that elevated level had an unfavorable impact on osteosarcoma patients' overall survival (OS) (HR = 1.82; 95% CI: 1.61–2.06; p < 0.001) and event-free survival (EFS) (HR = 1.97; 95% CI: 1.61–2.42; p < 0.001). Combined RRs of SALP indicated that elevated level was associated with presence of metastasis at diagnosis (RR = 5.55; 95% CI: 1.61–9.49; p = 0.006). No significantly different results were obtained after stratified by variables of age range, cancer stage, sample size, and geographic region. Conclusion. This meta-analysis demonstrated that high SALP level is significantly associated with poor OS or EFS rate and presence of metastasis at diagnosis. SALP level is a convenient and effective biomarker of prognosis for osteosarcoma.

Osteosarcoma tissues and cell lines from patients with differing serum alkaline phosphatase concentrations display minimal differences in gene expression patterns

Serum alkaline phosphatase (ALP) concentration is a prognostic factor for osteosarcoma in multiple studies, although its biological significance remains incompletely understood. To determine whether gene expression patterns differed in osteosarcoma from patients with differing serum ALP concentrations, microarray analysis was performed on 18 primary osteosarcoma samples and six osteosarcoma cell lines from dogs with normal and increased serum ALP concentration. No differences in gene expression patterns were noted between tumours or cell lines with differing serum ALP concentration using a gene-specific two-sample t-test. Using a more sensitive empirical Bayes procedure, defective in cullin neddylation 1 domain containing 1 (DCUN1D1) was increased in both the tissue and cell lines of the normal ALP group. Using quantitative PCR (qPCR), differences in DCUN1D1 expression between the two groups failed to reach significance. The homogeneity of gene expression patterns of osteosarcoma associated differing serum ALP concentrations are consistent with previous studies suggesting serum ALP concentration is not associated with intrinsic differences of osteosarcoma cells.

A novel assessment method of serum alkaline phosphatase for the diagnosis of osteosarcoma in children and adolescents

BACKGROUND

A high serum alkaline phosphatase (ALP) level is valuable for the diagnosis of osteosarcoma in adults, but its use in teenagers is problematic because ALP levels are affected by age, gender, and pubertal stage. Because serum acid phosphatase (ACP) shows the same tetraphasic pattern as serum ALP in children and adolescents, we presumed that serum levels of ALP and ACP would have a strong correlation and that the ratio of ALP to ACP (ALP/ACP) would show little variation and would be useful for the diagnosis of osteosarcoma in teenagers. The purpose of this study was to evaluate the correlation between the serum levels of ALP and ACP and to investigate the validity of ALP/ACP in the differential diagnosis of osteosarcoma in children and adolescents.

METHODS

We retrospectively examined 538 patients aged 1-18 years, including 24 with osteosarcomas, 8 with other malignant bone tumors, 56 with benign bone tumors, and with 450 non-tumor lesions (controls). We evaluated the serum levels of ALP and ACP, both obtained by preoperative examination.

RESULTS

There were significant correlations between the serum ALP and ACP levels in the controls (r = 0.805 in males and r = 0.860 in females). The ratios of ALP to ACP in the controls showed little variation with age. In ROC curve analysis, to discriminate between the osteosarcomas and the controls, the cutoff levels of serum ALP and ALP/ACP were 956 (U/l) and 50.9 in males and 748 (U/l) and 43.3 in females, respectively. The sensitivity and specificity of serum ALP and ALP/ACP in the differential diagnosis of osteosarcoma were 50.0 and 89.0%, and 60.0 and 94.1%, respectively in males, and 61.5 and 72.7%, and 69.2 and 84.2%, respectively, in females.

CONCLUSIONS

The results suggest that ALP/ACP is more useful than the serum ALP level in diagnosing osteosarcoma because it is little affected by the age.

Atypical Presentation of High-Grade Intramedullary Osteosarcoma with Bilateral Cervical, Supraclavicular, and Axillary Lymphadenopathy: A Case Report and Literature Review

Osteosarcoma typically presents with primary site pain. The authors report a case of extensive metastatic osteosarcoma without any complaint of primary site pain during initial presentation. The 23-year-old female patient presented with simultaneous multiple cervical, supraclavicular, and axillary lymphadenopathy, as well as two large subcutaneous fat tumours. Despite initial excision biopsy of cervical lymph nodes, the diagnosis of osteosarcoma was only clinched after open biopsy of the right distal femur lesions and further histological evaluation. Though the patient was promptly started on neo-adjuvant chemotherapy and achieved excellent histological response to treatment, the disease had relapsed quickly and she succumbed to the disease one year after initial presentation. This report highlights the need to be vigilant in the workup and investigation of osteosarcoma, as the presenting symptoms may be more heterogenous than the conventional teaching of primary site pain.

Prognostic value of histological response to chemotherapy in osteosarcoma patients receiving tumor-bearing frozen autograft

Background

A variety of surgical procedures are now available for tissue reconstruction after osteosarcoma excision, and an important prognostic factor is the evaluation of response to chemotherapy using histology. Although tumor-bearing autografts are useful tools for reconstruction, re-use of the primary tumor may make it difficult to assess the histological response to chemotherapy, since the entire tumor cannot be analyzed. Here, we analyzed the prognostic value of the histological response in the patients who received frozen tumor-bearing autografts for reconstruction.

Method

Retrospective analysis of the medical records of 51 patients with high-grade osteosarcoma of the extremities was performed. All patients received reconstruction using frozen tumor-bearing autografts. Tumor necrosis was evaluated in extraskeletal masses and cancellous bone.

Results

Five-year overall survival of patients with good and poor response to chemotherapy was 82.9% and 46.4%, respectively (P = 0.044), and 5-year event-free survival was 57.7% and 36.0%, respectively (P = 0.329). Multivariate analysis revealed that a poor histological response to chemotherapy was a significant prognostic factor for overall survival (P = 0.033).

Conclusion

Histological response is an important and reliable prognostic factor in patients undergoing reconstruction using frozen tumor-bearing autografts.

High serum alkaline phosphatase cooperating with MMP-9 predicts metastasis and poor prognosis in patients with primary osteosarcoma in Southern China

Background

Osteosarcoma is a malignant tumor with high ability to form invasion and metastasis. Identifying prognostic factor in osteosarcoma is helpful to select those patients for more aggressive management. Our study evaluated serum alkaline phosphatase (ALP) cooperating with matrix metalloproteinase-9 (MMP-9) as an important prognostic predictor for local recurrence and distant metastasis of osteosarcoma.

Methods

177 cases were included from the osteosarcoma patients treated at 1st Affiliated Hospital of Sun Yat-sen University (1999-2008). Pre-chemotherapy serum ALP (pre-ALP) were studied and correlated with tumor recurrence, lung metastasis and patient survival. MMP-9 protein in tumor tissues was detected by immunohistochemistry and correlated with pre-ALP level.

Results

Pre-ALP were partitioned into normal, high, and very high groups, in each group the incidence of metastases was 12.2%, 21.2% and 34.6%, respectively (p = 0.007). In the three groups the mean disease-free survival (DFS) was 57 ± 3.15, 28 ± 3.57 and 14 ± 3.35 months, respectively (p < 0.001); overall survival (OS) was 92 ± 26.89, 39 ± 8.61 and 17 ± 5.07 months, respectively (p < 0.001). By multivariate analysis, elevated serum pre-ALP were associated with shorter DFS (p = 0.018) and OS (p = 0.031). If elevated ALP levels decreased after clinical treatment, the incidence of lung metastasis rate decreased (p = 0.028); DFS and OS were both prolonged (p < 0.001). Pre-ALP was also positively correlated with MMP-9 expression (p = 0.015) in tumor tissue.

Conclusions

Pre-ALP was an independent prognostic factor for the survival of osteosarcoma patients in south China, and correlated with MMP-9 expression and lung metastasis. ALP can also serve as a prognostic marker for treatment, and merit large-scale validation studies.

Surgical management of primary bone tumors of the spine: validation of an approach to enhance cure and reduce local recurrence

STUDY DESIGN

Multicenter ambispective cohort analysis.

OBJECTIVE

The purpose of this study is to determine whether applying Enneking's principles to surgical management of primary bone tumors of the spine significant decreases local recurrence and/or mortality.

SUMMARY OF BACKGROUND DATA

Oncologic management of primary tumors of spine has historically been inconsistent, controversial, and open to individual interpretation.

METHODS

A multicenter ambispective cohort analysis from 4 tertiary care spine referral centers was done. Patients were analyzed in 2 cohorts, "Enneking Appropriate" (EA), surgical margin as recommended by Enneking, and "Enneking Inappropriate" (EI), surgical margin not recommended by Enneking. Benign tumors were not included in mortality analysis.

RESULTS

Two cohorts represented an analytic dataset with 147 patients, 86 male, average age 46 years (range: 10-83). Median follow-up was 4 (2-7) years in the EA and 6 (5.5-15.5) years in the EI. Seventy-one patients suffered at least 1 local recurrence during the study, 57 of 77 in the EI group and 14 of 70 in the EA group. EI surgical approach caused higher risk of first local recurrence (P < 0.0001). There were 48 deaths in total; 29 in the EI group and 19 in the EA. There was a strong correlation between the first local recurrence and mortality with an odds ratio of 4.69, (P < 0.0001). EI surgical approach resulted in a higher risk of mortality with a hazard ratio of 3.10, (P = 0.0485) compared to EA approach.

CONCLUSION

Surgery results in a significant reduction in local recurrence when primary bone tumors of the spine are resected with EA margins. Local recurrence has a high concordance with mortality in resection of these tumors. A significant decrease in mortality occurs when EA surgery is used.

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

PURPOSE

Whether neoadjuvant chemotherapy safely allows close margins in osteosarcoma patients is still unknown. This study investigates the impact of close margins on local recurrence (LR) and overall survival (OS) for osteosarcoma patients treated with neoadjuvant chemotherapy.

METHODS

We retrospectively reviewed 47 cases of conventional osteosarcoma who were treated at our institution. Patient and treatment factors such as age, gender, MSTS stage, tumour site, surgery type, pathological type, tumour size, surgical margin, tumour necrosis rate, chemotherapy regimens and cycles were recorded. A close margin was defined as tumour present less than 5 mm from the closest resection margin. The average followup was 87.6 months (range, 25-135 months).

RESULTS

Twenty-five patients were alive, 22 patients had died, and eight had LR. Twenty-eight patients had wide margins, seven had positive margins and 12 had close margins. Positive margins had a greater risk of LR (57.1%) than wide margins and close margins. There was no difference in LR (8.3% vs 10.7%) between close margins and wide margins. Margin status was not correlated with OS.

CONCLUSION

Compared with wide margins, close margins did not lead to increased local recurrence in our study group. Whether close margins, as defined in our study, are just as acceptable as wide margins in terms of patient outcomes for osteosarcoma patients with neoadjuvant chemotherapy needs to be further confirmed in the future.

The relation of tumour necrosis and survival in patients with osteosarcoma

PURPOSE

We investigated whether tumour necrosis was associated with disease-free survival (DFS) and overall survival (OS) of osteosarcoma patients treated in our institution.

METHODS

We retrospectively studied the predictive value of percentage of necrosis in 40 cases of IIB osteosarcoma treated from 1999 to 2008 in our institution. Patient and treatment factors such as age, gender, tumour site, surgery type, pathological type, tumour size, margin status, percentage of tumour necrosis, chemotherapy regimens and cycles were recorded. The average follow-up was 85.9 months (range, 25-135 months).

RESULTS

Two patients had local recurrence (LR) alone, five patients had both LR and metastasis, 14 patients had metastasis alone. Twenty-four patients were alive and 16 had died. The five-year DFS and OS were 47.8% and 65.9%, respectively. Tumour necrosis grouped by 90% was not associated with DFS and OS. Patients with greater than 70% necrosis rate had a significantly higher DFS than those with less than 70%.

CONCLUSION

We found no survival advantage at 90% tumour necrosis in our study. Further study with more patients should be performed to evaluate the predictive value of necrosis rate at the cutoff of 70%.

Free vascularised fibular graft for reconstruction of defects of the lower limb after resection of tumour

We describe a retrospective review of 38 cases of reconstruction following resection of the metaphysiodiaphysis of the lower limb for malignant bone tumours using free vascularised fibular grafts. The mean follow-up was for 7.6 years (0.4 to 18.4). The mean Musculoskeletal Tumor Society score was 27.2 (20 to 30). The score was significantly higher when the graft was carried out in a one-stage procedure after resection of the tumour rather than in two stages. Bony union was achieved in 89% of the cases. The overall mean time to union was 1.7 years (0.2 to 10.3). Free vascularised fibular transfer is a major operation with frequent, but preventable, complications which allows salvage of the limb with satisfactory functional results.

Multifocal osteosarcoma in childhood

Osteosarcoma is one of the most common primary malignant bone tumours in childhood, mainly affecting the metaphysis of long extremity bones. In rare cases, patients present at time of diagnosis with multiple bone lesions, sometimes in the absence of pulmonary metastases. The pathology pattern of these multifocal osteosarcomas occurring with a rare incidence of 0.5-4% is not yet clear, and in spite of investigations in diagnosis and therapy, the prognosis is still poor. We report two cases of multifocal synchronous osteosarcoma. The age of both children at the time of tumour detection was 14 years. A synchronous or metachronous occurrence of multiple bone lesions, initially in the absence of pulmonary metastases was seen. In both cases, treatment consisted of neoadjuvant chemotherapy, oncologic surgery and adjuvant chemotherapy. Tumour response to chemotherapy was good in one patient, and poor in the other case. In both patients initial R0-resection of the tumours was performed. The disease-free time was 1 year before detection of pulmonary metastases or relapse. By the combination of chemotherapy and aggressive surgery the prognosis in multifocal osteosarcoma has been improved over the last years. Nevertheless, the survival time is still short and seems to be correlated with the initial histological tumour response to chemotherapy.

Prognostic factors and outcomes for osteosarcoma: an international collaboration

We aimed to evaluate the prognostic significance of traditional clinical predictors in osteosarcoma through an international collaboration of 10 teams of investigators (2680 patients) who participated. In multivariate models the mortality risk increased with older age, presence of metastatic disease at diagnosis, development of local recurrence when the patient was first seen, use of amputation instead of limb salvage/wide resection, employment of unusual treatments, use of chemotherapeutic regimens other than anthracycline and platinum and use of methotrexate. It was also influenced by the site of the tumour. The risk of metastasis increased when metastatic disease was present at the time the patient was first seen and also increased with use of amputation or unusual treatment combinations or chemotherapy regimens not including anthracycline and platinum. Local recurrence risk was higher in older patients, in those who had local recurrence when first seen and when no anthracycline and platinum were used in chemotherapy. Results were similar when limited to patients seen after 1990 and treated with surgery plus combination chemotherapy. This large-scale international collaboration identifies strong predictors of major clinical outcomes in osteosarcoma.