Use of Imaging to Optimise Prostate Cancer Tumour Volume Assessment for Focal Therapy Planning

Abstract

Purpose of Review Rapid advances in imaging of the prostate have facilitated the development of focal therapy and provided a non-invasive method of estimating tumour volume. Focal therapy relies on an accurate estimate of tumour volume for patient selection and treatment planning so that the optimal energy dose can be delivered to the target area(s) of the prostate while minimising toxicity to surrounding structures. This review provides an overview of different imaging modalities which may be used to optimise tumour volume assessment and critically evaluates the published evidence for each modality. Recent Findings Multi-parametric MRI (mp-MRI) has become the standard tool for patient selection and guiding focal therapy treatment. The current evidence suggests that mp-MRI may underestimate tumour volume, although there is a large variability in results. There remain significant methodological challenges associated with pathological processing and accurate co-registration of histopathological data with mp-MRI. Advances in different ultrasound modalities are showing promise but there has been limited research into tumour volume estimation. The role of PSMA PET/CT is still evolving and further investigation is needed to establish if this is a viable technique for prostate tumour volumetric assessment. Summary mp-MRI provides the necessary tumour volume information required for selecting patients and guiding focal therapy treatment. The potential for underestimation of tumour volume should be taken into account and an additional margin applied to ensure adequate treatment coverage. At present, there are no other viable image-based alternatives although advances in new technologies may refine volume estimations in the future.

Automatic Segmentation of Pelvic Cancers Using Deep Learning: State-of-the-Art Approaches and Challenges

“…Tumor size measurement is important as it directs clinical decisions for the choice of treatment and evaluation of treatment response [46,47]. Disease monitoring is essential for assessing response to RT and chemotherapy treatments.…”

Combining prostate health index and multiparametric magnetic resonance imaging in estimating the histological diameter of prostate cancer

“…Accurately estimating the tumor boundary is key to successful focal therapy, and it can also decrease the positive margin rate after radical prostatectomy. Although mpMRI is the most commonly used tool to estimate tumor volume [ 5 ], underestimation of the histological tumor volume has frequently been reported [ 10 , 11 ]. This may be because at the periphery of the index tumor the cancer may be low grade or intermixed with normal prostatic tissue, making the tumor inconspicuous on mpMRI [ 26 ].…”

“…Based on the high sensitivity and specificity for clinically significant prostate cancer, mpMRI is widely used to assess the tumor location and volume [ 5 ]. The tumor diameter on mpMRI has been correlated with extraprostatic extension, seminal vesicle invasion, and positive margin after radical prostatectomy [ 6 ].…”

Automatic Segmentation of Pelvic Cancers using Deep Learning: State-of-the-Art Approaches and Challenges

“…Tumor size measurement is important as it directs clinical decisions for the choice of treatment and evaluation of treatment response [41,42]. Disease monitoring is essential for assessing response to RT and chemotherapy treatments.…”