The LabPS score: Inexpensive, Fast, and Site-agnostic Survival Prediction

Abstract

Objectives: To provide a widely applicable, blood-biomarker-based and performance-status-based prognostic model, which predicts the survival of patients undergoing palliative non-brain radiotherapy. This model has already been examined in a cohort of patients treated for brain metastases and performed well.

Methods: This was a retrospective single-institution analysis of 375 patients, managed with non-ablative radiotherapy to extracranial targets, such as bone, lung, or lymph nodes. Survival was stratified by LabPS score, a model including serum hemoglobin, platelets, albumin, C-reactive protein, lactate dehydrogenase, and performance status. Zero, 0.5, or 1 point was assigned and the final point sum calculated. A higher point sum indicates shorter survival.

Results: The LabPS score predicted overall survival very well (median 0.6 to 26.5 mo, 3-month rate 0% to 100%, 1-year rate 0% to 89%), P=0.0001. However, the group with the poorest prognosis (4.5 points) was very small. Most patients with comparably short survival or radiotherapy administered in the last month of life had a lower point sum. Additional prognostic factors, such as liver metastases, opioid analgesic use, and/or corticosteroid medication, were identified.

Conclusions: If busy clinicians prefer a general prognostic model rather than a panel of separate diagnosis-specific/target-specific scores, they may consider validating the LabPS score in their own practice. In resource-constrained settings, inexpensive standard blood tests may be preferable over imaging-derived prognostic information. Just like other available scores, the LabPS cannot identify all patients with very short survival.