Controversies and Challenges in the Management of Osteosarcoma-an Indian Perspective

Determinants of tumor necrosis and its impact on outcome in patients with Localized osteosarcoma uniformly treated with a response adapted regimen without high dose Methotrexate- A retrospective institutional analysis

Purpose

Response to neoadjuvant chemotherapy in form of tumor necrosis predicts outcome in osteosarcoma; although response-adapted treatment escalation failed to improve outcome among patients treated with high-dose methotrexate-based (HDMTx) chemotherapy. This study aimed to identify factors predicting tumor necrosis and its impact on survival among patients with non-metastatic osteosarcoma treated with a response-adapted non-HDMTx regimen.

Methods

A retrospective single-institutional study was conducted among non-metastatic osteosarcoma patients treated with neoadjuvant therapy between 2004-2019. Patients were treated uniformly with three cycles of neoadjuvant cisplatin/doxorubicin. Post-operatively, patients with favourable necrosis (≥90 %) received 3 cycles of cisplatin/doxorubicin, while patients with poor necrosis (<90 %) received escalated treatment with alternating six cycles of cisplatin/doxorubicin and ifosfamide/etoposide. Propensity score matching (PSM) analyses were conducted to ascertain independent impact of necrosis on event-free survival (EFS) and overall survival (OS).

Results

Of 594 registered osteosarcoma patients, 280 patients (median age 17 years; male 67.1 %) were included for analysis. 73 patients (26.1 %) achieved favourable necrosis. Patients with smaller tumor size (≤10 cm) (aOR = 2.28; p = 0.030), lower serum alkaline phosphatase (≤450 IU/L) (aOR = 2.10; p = 0.035), and who had surgery earlier (<115 days) (aOR = 2.28; p = 0.016) were more likely to have favourable necrosis. On 1:2 PSM analysis, patients not achieving favourable necrosis demonstrated inferior EFS (HR = 2.68; p = 0.003) and OS (HR = 3.42; p = 0.003).

Conclusions

Patients of osteosarcoma with smaller tumor, lower serum alkaline phosphatase and earlier surgery are more likely to achieve favourable necrosis. Tumor necrosis independently predicts outcome in osteosarcoma, and response-adapted treatment escalation fails to overcome the adverse impact of poor necrosis in non-HDMTx based regimen.

Impact of delay of local control in nonmetastatic extremity primary osteosarcoma

INTRODUCTION

The timing of local control (LC) is not well studied in osteosarcoma. We assessed the impact of the delay of LC on the survival outcome of patients with osteosarcoma.

METHODS

We conducted a retrospective analysis of children (≤18 years) with nonmetastatic extremity primary osteosarcoma at King Hussein Cancer Center from January 2005 until March 2020. Patients' demographics, disease characteristics, and outcomes were collected. Events were defined as death, progression, or relapse. Cox proportional hazards regression was used for univariable and multivariable comparisons of different covariates.

RESULTS

Eighty-two patients were included; 41 (50%) were females; the median age was 12.5 years (range: 5.9-18). Sixty-four patients (78%) underwent LC by limb-salvage surgery. Fifteen patients (18%) had a delay of LC greater than or equal to 18 weeks. After a median follow-up of 54 months (range: 8-188), the 5-year event-free survival (EFS) and overall survival (OS) were 55.3% ± 5.8% and 66.6% ± 6%, respectively. On univariable analysis, LC greater than or equal to 18 weeks, progression before LC, amputation, and poor histologic response were associated with worse EFS (p = .007, .007, .006, .002) and OS (p = .01, .001, .006, .004). On multivariable analysis, LC greater than or equal to 18 weeks, progression before LC, and poor histologic response were associated with worse EFS (p < .001, .007, .002); and OS (p < .001, .007, .008). Male gender was associated with worse OS on univariable and multivariable analysis (both p = .02). After exclusion of patients with early progression before Week 11, good histologic response and LC less than 18 weeks were associated with better EFS (p = .04 and .03). While good histologic response was associated with better OS (p = .02), LC less than 18 weeks was not significant (p = .2).

CONCLUSIONS

Our findings suggest that delay in LC could have an impact on the outcomes in patients with osteosarcoma. However, further investigations involving larger sample sizes and longer follow-up are necessary to fully comprehend the extent of this influence.

Formulation and validation of a baseline prognostic score for osteosarcoma treated uniformly with a non-high dose methotrexate-based protocol from a low middle income healthcare setting: a single centre analysis of 594 patients

Introduction

The outcomes of osteosarcoma in low middle income countries (LMICs) are different due to patients presenting in advanced stages, resource constraints and the use of non-high-dose-methotrexate (HDMTX)-based regimens. This study derived and validated a prognostic score for osteosarcoma that integrates biologic and social factors and is tailored for patients from an LMIC setting using a non-HDMTX-based protocol.

Materials and methods

A retrospective study including osteosarcoma patients enrolled for treatment at a single tertiary care centre in India between 2003-19 was conducted. Baseline biologic and social characteristics were extracted from medical records and survival outcomes were noted. The cohort was randomised into a derivation and validation cohort. Multivariable Cox regression was used to identify baseline characteristics that were independently prognostic for survival outcomes in the derivation cohort. A score was derived from the prognostic factors identified in the derivation cohort and further validated in the validation cohort with estimation of its predictive ability.

Results

594 patients with osteosarcoma were eligible for inclusion in the study. Around one-third of the cohort had metastatic disease with 59% of the patients residing in rural areas. The presence of metastases at baseline (HR 3.39; p<0.001; score=3), elevated serum alkaline phosphatase (SAP) >450 IU/L (HR 1.57; p=0.001; score=1) and baseline tumour size > 10 cm (HR 1.68; p<0.001; score=1) were identified to be independent factors predicting inferior event free survival (EFS) and were included in development of the prognostic score. Patients were categorized as low risk (score 0), intermediate risk (score 1-3) and high risk (4-5). Harrell's c-indices for the score were 0.682, 0.608 and 0.657 respectively for EFS in the derivation, validation and whole cohort respectively. The timed AUC of ROC was 0.67 for predicting 18-month EFS in the derivation, validation and whole cohorts while that for 36-month EFS were 0.68, 0.66 and 0.68 respectively.

Conclusions

The study describes the outcomes among osteosarcoma patients from an LMIC treated uniformly with a non-HDMTX-based protocol. Tumor size, baseline metastases and SAP were prognostic factors used to derive a score with good predictive value for survival outcomes. Social factors did not emerge as determinants of survival.

Non-invasive intravoxel incoherent motion MRI in prediction of histopathological response to neoadjuvant chemotherapy and survival outcome in osteosarcoma at the time of diagnosis

BACKGROUND

Early prediction of response to neoadjuvant chemotherapy (NACT) is important to aid personalized treatment in osteosarcoma. Diffusion-weighted Intravoxel Incoherent Motion (IVIM) MRI was used to evaluate the predictive value for response to NACT and survival outcome in osteosarcoma.

METHODS

Total fifty-five patients with biopsy-proven osteosarcoma were recruited prospectively, among them 35 patients were further analysed. Patients underwent 3 cycles of NACT (Cisplatin + Doxorubicin) followed by surgery and response adapted adjuvant chemotherapy. Treatment outcomes were histopathological response to NACT (good-response ≥ 50% necrosis and poor-response < 50% necrosis) and survival outcome (event-free survival (EFS) and overall survival (OS)). IVIM MRI was acquired at 1.5T at baseline (t0), after 1-cycle (t1) and after 3-cycles (t2) of NACT. Quantitative IVIM parameters (D, D*, f & D*.f) were estimated using advanced state-of-the-art spatial penalty based IVIM analysis method bi-exponential model with total-variation penalty function (BETV) at 3 time-points and histogram analysis was performed.

RESULTS

Good-responders: Poor-responders ratio was 13 (37%):22 (63%). EFS and OS were 31% and 69% with 16.27 and 25.9 months of median duration respectively. For predicting poor-response to NACT, IVIM parameters showed AUC = 0.87, Sensitivity = 86%, Specificity = 77% at t0, and AUC = 0.96, Sensitivity = 86%, Specificity = 100% at t1. Multivariate Cox regression analysis showed smaller tumour volume (HR = 1.002, p = 0.001) higher ADC-25th-percentile (HR = 0.047, p = 0.005) & D-Mean (HR = 0.1, p = 0.023) and lower D*-Mean (HR = 1.052, p = 0.039) were independent predictors of longer EFS (log-rank p-values: 0.054, 0.0034, 0.0017, 0.0019 respectively) and non-metastatic disease (HR = 4.33, p < 10-3), smaller tumour-volume (HR = 1.001, p = 0.042), lower D*-Mean (HR = 1.045, p = 0.056) and higher D*.f-skewness (HR = 0.544, p = 0.048) were independent predictors of longer OS (log-rank p-values: < 10-3, 0.07, < 10-3, 0.019 respectively).

CONCLUSION

IVIM parameters obtained with a 1.5T scanner along with novel BETV method and their histogram analysis indicating tumour heterogeneity were informative in characterizing NACT response and survival outcome in osteosarcoma.

An Audit of Delays in the Management of Non-Metastatic Osteosarcoma at a Tertiary Care Center in South India

Background and objective Delays in the management of osteosarcoma (OGS) lead to tumor progression and the development of metastasis, resulting in a decrease in overall survival (OS). The primary objective of this study was to determine whether delays occur in implementing the individual steps in the management of OGS in South India. Methods In this study, core biopsy reports between October 2019 and October 2021 were retrospectively examined for a diagnosis of OGS. The primary outcome variables in this study were time to MRI, time to biopsy, time to biopsy report, time to neoadjuvant chemotherapy (NACT), time to surgery, and time to adjuvant chemotherapy (ACT). Statistical analysis was performed by comparing the outcome variables with the hypothesized mean. Results There were 38 patients with primary non-metastatic OGS. Of these, 92% received NACT, and 74% completed full treatment. The mean time to MRI was 11.3 ± 6.7 days, mean time to NACT was 15.3 ± 12.7 days, mean time to surgery was 31.1 ± 15.3 days, and mean time to ACT was 29.7 ± 10.1 days. Time to MRI was more than seven days in 68% of the cases, while time to NACT was more than seven days in 74%. Time to surgery was more than 21 days in 83% of the cases, and time to ACT was more than 21 days in 82% of the cases. Conclusion Based on our findings, there is a significant delay (p<0.05) in time to MRI, time to NACT, time to surgery, and time to ACT. The delay in time to surgery is more than the delay in time to MRI, time to NACT, and time to ACT. The delay is due to a variety of reasons, the most common being the long waiting period at the hospital.