Description

PDAC is one of the leading causes of cancer deaths in the UK, with the number of deaths resembling the number of new cases each year. Long term survival is poor, with around 3% of patients alive at 5 years, reducing to 1% at 10 years. Outcomes have shown minor improvement over the past few decades, with little impact in survival being achieved. This is a worldwide problem, with pancreatic cancer being 7th cause of cancer death.

Although progress has been made in terms of assessing the molecular profiling of pancreatic cancer, there has been little progress in some of the clinical aspects e.g. optimal radiological assessment to stratify patients. Currently imaging criteria following neo-adjuvant treatment has been shown to be sub-optimal in accurately defining response to treatment, which may prevent patients from receiving the treatment that gives them the best outcomes. The emerging paradigm in using pre-operative treatment (chemotherapy +/- RT) to improve outcomes for patients is likely to become the standard of care, increasing the need for advanced imaging assessments that accurately stratify patients by enhancing what is currently assessable on morphological images.

Quantified imaging biomarkers (QIMB) and radiomics are a highly promising area of RT research which will enhance the future direction of personalised treatment. Groups have used said research to examine tumour response; predict toxicity; and adapt RT for some anatomical sites. However, this area of research is particularly challenging in the abdomen, where many uncertainties exist, e.g. motion of pancreas and organs at risk; and poor image quality due to motion artefacts on imaging. New promising data is emerging from centres where patients are being treated with MR guided radiotherapy (MRgRT) systems. These include serial image analysis using delta radiomics that can predict early response in tumour; and feasibility of acquiring functional MR throughout treatment that shows apparent diffusion coefficient (ADC) change in tumour and a correlation to response. Very little work has been done to measure ADC changes during RT and this is where potential to adapt RT lies.

Diffusion MRI (dMRI) allows increased monitoring of functional changes during or post RT by providing information on the biological characteristics of tissue. Recent data even shows promise in the correlation of treatment outcome to ADC measured or compared pre and post RT, by correlating change in ADC to pathologic response; as a tool to predict patients likely to have a successful R0 resection; and in predicting patients who will not respond to CRT and may require a different disease management.