Field effect induced organ distension (FOrge) features predicting biochemical recurrence from pre-treatment prostate MRI

Abstract

Aggressive cancers are known to induce field effect that affect large areas of cells at a tissue surface. This means that local deformation induced by the tumor as it grows could cause distensions in regions distant from the tumor, presumably even the surface of the organ within which the tumor is growing. In this work, we focused on evaluating whether more and less aggressive prostate cancers (i.e. tumors that subsequently resulted in disease recurrence or not) could differentially induce changes and distensions in the surface of the prostate capsule. Specifically we have developed the concept of a new imaging marker called FOrge features, that attempts to quantify the degree and nature of the deformation induced in the capsule surface on account of tumor growth and then sought to evaluate whether FOrge is predictive of the risk of biochemical recurrence in prostate cancer patients based off a pre-operative T2w MRI scan. The FOrge features were extracted from a spatially contextual surface of interest (SOI) of the prostate capsule, uniquely determined from statistically significant shape differences between prostate atlases constructed from patients who did (BCR+) and who did not (BCR−) undergo biochemical recurrence. A random forest classifier trained on the FOrge features extracted from atlas images (25 BCR+ and 25 BCR−) yielded an accuracy of 78% and an AUC of 0.72 in an independent validation set of 30 patients.