Decision-making performance of large language models vs. human physicians in challenging lung cancer cases: A real-world case-based study

Background: Despite the promise shown by large language models (LLMs) for standardized tasks, their multidimensional performance in real-world oncology decision-making remains unevaluated. This study aims to introduce a framework for evaluating LLMs and physician decisions in challenging lung cancer cases. Methods: We curated 50 challenging lung cancer cases (25 local and 25 published) classified as complex, rare, or refractory. Blinded three-dimensional, five-point Likert evaluations (1–5 for comprehensiveness, specificity, and readability) compared standalone LLMs (DeepSeek R1, Claude 3.5, Gemini 1.5, and GPT-4o), physicians by experience level (junior, intermediate, and senior), and AI-assisted juniors; intergroup differences and augmentation effects were analyzed statistically. Results: Of 50 challenging cases (18 complex, 17 rare, and 15 refractory) rated by three experts, DeepSeek R1 achieved scores of 3.95 ± 0.33, 3.71 ± 0.53, and 4.26 ± 0.18 for comprehensiveness, specificity, and readability, respectively, positioning it between intermediate (3.68, 3.68, 3.75) and senior (4.50, 4.64, 4.53) physicians. GPT-4o and Claude 3.5 reached intermediate physician–level comprehensiveness (3.76 ± 0.39, 3.60 ± 0.39) but junior-to-intermediate physician–level specificity (3.39 ± 0.39, 3.39 ± 0.49). All LLMs scored higher on rare cases than intermediate physicians but fell below junior physicians in refractory-case specificity. AI-assisted junior physicians showed marked gains in rare cases, with comprehensiveness rising from 2.32 to 4.29 (84.8%), specificity from 2.24 to 4.26 (90.8%), and readability from 2.76 to 4.59 (66.0%), while specificity declined by 3.2% (3.17 to 3.07) in refractory cases. Error analysis showed complementary strengths, with physicians demonstrating reasoning stability and LLMs excelling in knowledge updating and risk management. Conclusions: LLMs performed variably in clinical decision-making tasks depending on case type, performing better in rare cases and worse in refractory cases requiring longitudinal reasoning. Complementary strengths between LLMs and physicians support case- and task-tailored human–AI collaboration.