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External validation of a prognostic score for oesophageal cancer (PSOC) for patients treated with palliative intent in a resource-limited setting
DOI:
https://doi.org/10.7196/Keywords:
Oesophageal cancer; palliative care; prognostic score; risk stratification; external validation; survival analysis; AUROC; calibration; Brier score; South Africa.Abstract
Background. Oesophageal cancer (OC) is common in South Africa (SA), where late presentation limits curative treatment. In resource- constrained settings, staging may not benefit patients with a poor prognosis. The prognostic score for oesophageal cancer (PSOC), based on Eastern Cooperative Oncology Group performance status scale, body mass index and serum albumin, was previously developed to predict short-term survival.
Objective. To externally validate PSOC in an independent cohort.
Methods. We performed a retrospective validation study using prospectively collected data from two public sector hospitals in KwaZulu- Natal Province, SA. Eligible patients had histologically confirmed OC and complete PSOC data, and were treated with palliative intent. The primary endpoint was survival ≥3 months. Logistic regression assessed associations between PSOC and survival. Discrimination was quantified using the area under the receiver operating characteristic curve (AUROC), calibration with the Hosmer-Lemeshow test and accuracy with the Brier score. Secondary analyses evaluated overall survival (OS) with Kaplan-Meier and Cox models.
Results. We included 465 patients (mean age 61 years; male:female ratio 1:1), 97% with squamous cell carcinoma. Higher PSOC scores predicted improved survival (score 4 v. 0: odds ratio 11.87, 95% confidence interval (CI) 4.87 - 28.91; p<0.001). AUROC was 0.681 (95% CI 0.630 - 0.732) with good calibration (Hosmer-Lemeshow p=0.920). Median OS was 4.8 months, with significant survival differences across score groups (log-rank p<0.001). The Brier score was 0.190, indicating good predictive accuracy.
Conclusion. PSOC is a simple, validated tool for predicting short-term survival in OC, and may guide decisions on staging v. palliation in high-incidence, resource-limited settings.
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