Estimating the Individualized Effect of Tooth Extraction before Radiotherapy on Osteoradionecrosis Using Causal...

Area of Science:

• Oncology
• Oral Surgery
• Radiotherapy

Background:

• Osteoradionecrosis (ORN) is a significant complication following radiotherapy for head and neck cancer (HNC).
• The role of prophylactic tooth extraction prior to radiotherapy in mitigating ORN risk is debated.
• Understanding heterogeneous treatment effects is crucial for personalized patient management.

Purpose of the Study:

• To determine the average treatment effect (ATE) of preradiotherapy tooth extraction on ORN risk in HNC patients.
• To estimate the conditional average treatment effect (CATE) to identify patients who benefit or are harmed by this intervention.
• To identify clinical factors that modify the treatment effect of preradiotherapy tooth extraction.

Main Methods:

• Retrospective cohort study of 2,466 adult HNC patients treated with curative radiotherapy (2011-2018).
• Causal survival forest model targeting restricted mean survival time (RMST) with 5-fold cross-validation.
• Augmented inverse probability weighting (AIPW) for calibration and rank-weighted average treatment effect (RATE) for treatment prioritization.

Main Results:

• The overall ATE of preradiotherapy extraction on ORN was not statistically significant (-0.26 months).
• Significant heterogeneous treatment effects (HTE) were observed, with some patients experiencing harm (Q1: -1.47 months RMST difference) and others benefiting (Q4: +0.94 months RMST difference).
• Eastern Cooperative Oncology Group performance status and periodontal grade were identified as independent modifiers of treatment benefit.

Conclusions:

• Preradiotherapy tooth extraction does not alter the overall ORN risk in HNC patients.
• Individualized treatment effects necessitate a move away from a one-size-fits-all approach.
• Targeted interventions based on patient-specific factors are essential for optimizing outcomes and minimizing ORN risk.