Prognostic factors for survival with metastatic spinal cord compression in the SCORAD randomized trial
Hoskin, Peter J Lopes, A. Hackshaw, A.
Hoskin, Peter J
Lopes, A.
Hackshaw, A.
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Abstract
Purpose/Objective(s): SCORAD randomized 686 patients with metastatic
spinal cord compression (MSCC) to receive either a single dose of
8Gy or 20Gy in 5 fractions; no significant difference in survival, recovery
of ambulatory status or pain control was seen (Hoskin et al, 2019). Survival
with MSCC after radiotherapy is poor and variable. The aim of this
study was to establish a prognostic model for predicting overall survival in
patients with MSCC.
Materials/Methods: The median overall survival in SCORAD is 13 weeks.
This time point has been used for the analysis. SCORAD data was
randomly divided into a training set (412, 60%) and a validation set (274,
40%) matched for key characteristics: treatment, ambulatory status, primary
tumor and extent of metastases. Multivariable Cox analysis used
twelve factors on the training set to select prognostic factors for overall
survival: treatment, sex, extent of metastases, number of MSCC sites,
baseline bowel and bladder function, prior chemotherapy, radiotherapy or
hormonal status, baseline ambulatory status, primary tumor and location of
MSCC. Using backward elimination with a significance level of 0.20 and
keeping treatment in the model, five factors were retained as prognostic
factors: sex, extent of metastases, primary tumor, baseline ambulatory
status and location of MSCC. Receiver operating characteristic (ROC)
analysis was performed to evaluate the accuracy of the reduced model in predicting 13-week overall survival. Specific cut-off values associated with
sensitivity rates for fixed false positive rate values were identified.
Results: The model indicates that, adjusted for treatment, females had
decrease risk of death compared with males (HR:0.66: 95% CI 0.47 to
0.92, p Z 0.02) as well as patients with SCC located in L1-S2 (HR:0.69:
95% CI 0.52 to 0.92, p Z 0.01) and T6-L5 (HR:0.71:95% CI 0.44 to 1.16,
p Z 0.17) compared with C1-T12. Poor survival was associated with
presence of nonskeletal mets [HR: 1.31: 95%CI 1.04 to 1.65 , p Z 0.02],
having lung (HR:3.98: 95% CI 2.85 to 5.54, p<0.001), gastrointestinal
cancer (HR: 2.97, 95% CI 2.02 to 4.37, p<0.001) or a cancer other than
prostate or breast cancer (HR:2.4: 95% CI 1.67 to 3.44, p<0.001). Patients
classified with impaired ambulatory status at baseline were also at
increased risk of death (grade 2, HR: 1.72: 95% CI 1.27 to 2.34, p Z
p<0.001; grade 3, HR: 2.5, 95% CI 1.79 to 3.48, p<0.001; grade 4, HR:
2.04: 95%CI 1.3 to 3.2, p Z 0.002). The prognostic performance of the
model was associated with a 13-weeks OS ROC area under the curve
(AUC) of 0.75, 95%CI: 0.69 to 0.81. The risk score 0.996 for the 13-
weeks OS had a false positive rate of 30% and corresponding sensitivity of
65.63%.
Conclusion: The accuracy of this prognostic model developed in SCORAD
is limited and is below the recommended level of AUC >0.85 for a strong
prognostic performance. However, this model will guide patient management
and provide the basis for stratification factors in further studies.
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Date
2020
Publisher
Collections
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Type
Meetings and Proceedings
Citation
Hoskin PJ, Lopes A, Hackshaw A. Prognostic factors for survival with metastatic spinal cord compression in the SCORAD randomized trial. International Journal of Radiation Oncology Biology Physics. 2020;108(3):S36-S