Fine-Tuning FLAN-T5 for Biomedical Lay Summarisation (BioLaySumm 2025)

Jan 1, 2025·
Jevi Waugh
Jevi Waugh
· 1 min read
FLAN-T5 architecture, LoRA adapters, and training results.
Abstract
This project investigates full fine-tuning and parameter-efficient adaptation of FLAN-T5 models for translating expert radiology reports into layperson-friendly summaries. Using the BioLaySumm 2025 dataset, we compare full fine-tuning, Low-Rank Adaptation (LoRA), and a gradient-free Evolution Strategies approach, analysing trade-offs between performance, compute cost, and parameter efficiency.
Type
This page provides a high-level overview only.
For full methodology, experiments, training scripts, and results, see the GitHub repository.

Overview

This project focuses on biomedical lay summarisation, translating expert-level radiology reports into language accessible to non-experts. The work fine-tunes instruction-tuned FLAN-T5 models on the BioLaySumm 2025 dataset and systematically evaluates different adaptation strategies.

Methods

Three optimisation strategies are explored:

  • Full Fine-Tuning (FFT): updates all model parameters.
  • LoRA (PEFT): updates a small set of low-rank adapter weights (~2–3% of parameters).
  • Evolution Strategies (ES): gradient-free optimisation via population-based parameter perturbations.

Performance is evaluated using ROUGE-1/2/L/Lsum, with analysis of compute cost, convergence behaviour, and parameter efficiency.

Key Findings

  • LoRA achieves comparable or slightly higher ROUGE scores than full fine-tuning while training only ~2–3% of parameters.
  • FLAN-T5-Base + LoRA provides the best balance of quality and efficiency.
  • Evolution Strategies offer fast iteration but underperform gradient-based methods for this task.

Example Visuals

LoRA adapter integration
Training curves comparison

Reproducibility & Code

All experiments were run on NVIDIA A100 GPUs using PyTorch and Hugging Face Transformers. Training scripts, hyperparameters, datasets, and seeds are fully documented in the repository.

👉 Full code and documentation:
https://github.com/Jevi-Waugh/BioLaySumm-Flan-T5/tree/topic-recognition/recognition/FLAN-T5-Jevi-Waugh