Rapid advances in prostate imaging have aided in the development of focal therapy and a non-invasive method of estimating tumor volume. To deliver the optimal energy dose to the prostate’s target area(s) while minimizing toxicity to surrounding structures, focal therapy relies on an accurate estimate of tumor volume for patient selection and treatment planning. 

Research provided an overview of various imaging modalities that may be used to optimize tumor volume assessment and evaluates the published evidence for each modality. Multi-parametric MRI (mp-MRI) has emerged as the gold standard for patient selection and directing focused therapy treatment. The available evidence implied that mp-MRI might underestimate tumor volume, albeit findings vary widely. Pathological processing and effective co-registration of histological data with mp-MRI continue to be key methodological obstacles. Although advances in many ultrasound techniques are promising, research into tumor volume estimates has been restricted. The use of PSMA PET/CT in prostate tumor volumetric evaluation is still changing, and further research is needed to determine whether this is a feasible approach.

mp-MRI offers the tumor volume information needed to select and direct focused therapy treatment. However, to achieve proper treatment coverage, the risk for underestimating tumor volume should be considered, and an extra margin should be implemented. There are no other suitable image-based options at the moment, while improvements in new technologies may refine volume calculations in the future.

Reference: link.springer.com/article/10.1007/s11934-020-00987-y