In many settings, including oncology, increasing the dose of treatment results in both increased efficacy and toxicity. With the increasing availability of validated biomarkers and prediction models, there is the potential for individualized dosing based on patient specific factors. We consider the setting where there is an existing dataset of patients treated with heterogenous doses and including binary efficacy and toxicity outcomes and patient factors such as clinical features and biomarkers. The goal is to analyze the data to estimate an optimal dose for each (future) patient based on their clinical features and biomarkers. We propose an optimal individualized dose finding rule by maximizing utility functions for individual patients while limiting the rate of toxicity. The utility is defined as a weighted combination of efficacy and toxicity probabilities. This approach maximizes overall efficacy at a prespecified constraint on overall toxicity. We model the binary efficacy and toxicity outcomes using logistic regression with dose, biomarkers and dose–biomarker interactions. To incorporate the large number of potential parameters, we use the LASSO method. We additionally constrain the dose effect to be non‐negative for both efficacy and toxicity for all patients. Simulation studies show that the utility approach combined with any of the modeling methods can improve efficacy without increasing toxicity relative to fixed dosing. The proposed methods are illustrated using a dataset of patients with lung cancer treated with radiation therapy.

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Purpose: To evaluate the current status of stereotactic body radiotherapy (SBRT) for early staged non-small cell lung cancer (NSCLC) at main cancer hospitals in China. Methods and Materials: The questionnaire was sent by mail and email to 21 hospitals, which include the patient enrollment, treatment technique, dose and fractionation, quality control, disease control and side effects. Results: Nineteen hospitals responded. It was found that SBRT has been used for early staged NSCLC in most of the hospitals participating in the survey. The patient characteristics and techniques were relatively consistent, but there were many controversies regarding dose fractionation and quality control. Conclusions: SBRT for early staged NSCLC has been applied at main cancer hospitals in China. However, considerable variation exists. The establishment of clinical guidelines and standardized quality control are crucial for further improvement.