JiaKun LI, YanQing LIU, Fang DU, ZhenHua YU, Yu FENG, Hui Wang, XianHao HUO
Accepted: 2025-09-25
To address the challenges faced by general-purpose medical large language models (LLMs) in the field of brain tumor care—namely the scarcity of domain-specific data, limited clinical adaptability, and insufficient accuracy of generated content—this paper proposes BrainTumorLLM, a specialized large language model tailored for brain tumor diagnosis and treatment. Built upon the Meta-Llama-3-8B-Instruct foundation model, BrainTumorLLM is optimized through Supervised Fine-tuning (SFT) and Reinforcement Learning with Human Feedback (RLHF), and trained using a self-constructed, high-quality dataset named BrainTumorQA. This dataset comprises 11,000 question-answer pairs, encompassing both macro-level medical knowledge (symptoms, diagnostic methods, treatment strategies) and micro-level clinical cases, including 1,252 de-identified real-world brain tumor MRI reports, with privacy safeguarded via anonymization and information constraint strategies. From a technical perspective, Low-Rank Adaptation (LoRA) is employed to enhance training efficiency. A two-tier prompting framework is designed to guide the model in generating domain-specific responses at both macro and micro levels. Furthermore, human feedback learning is integrated through an expert preference-driven optimization mechanism and the Proximal Policy Optimization (PPO) algorithm, reinforcing the clinical consistency of the generated content. Experimental results demonstrate that BrainTumorLLM significantly outperforms both general-purpose and medical-domain models on brain tumor-related question answering tasks. In automatic evaluations, it achieves BLEU-1 and BLEU-2 scores of 0.3383 and 0.2684, respectively, and ROUGE-1, ROUGE-2, and ROUGE-L scores of 0.3237, 0.1466, and 0.2611. Moreover, the model’s perplexity is substantially reduced from 20.362 (base model) to 7.674, highlighting its domain-specific precision, professional accuracy, and potential for clinical application. BrainTumorLLM offers a robust AI-powered tool to support brain tumor diagnosis, treatment planning, and medical research.