Current approaches, challenges and future directions for monitoring treatment response in prostate cancer

Abstract

Prostate cancer is the most commonly diagnosed non-cutaneous neoplasm in men in the United States and the second leading cause of cancer mortality. One in 7 men will be diagnosed with prostate cancer during their lifetime. As a result, monitoring treatment response is of vital importance. The cornerstone of current approaches in monitoring treatment response remains the prostate-specific antigen (PSA). However, with the limitations of PSA come challenges in our ability to monitor treatment success. Defining PSA response is different depending on the individual treatment rendered potentially making it difficult for those not trained in urologic oncology to understand. Furthermore, standard treatment response criteria do not apply to prostate cancer further complicating the issue of treatment response. Historically, prostate cancer has been difficult to image and no single modality has been consistently relied upon to measure treatment response. However, with newer imaging modalities and advances in our understanding and utilization of specific biomarkers, the future for monitoring treatment response in prostate cancer looks bright.

Keywords: monitoring treatment response; prostate cancer.

Figure 1

Large lesion at the right apex missed by TRUS biopsy in a patient for pre-active surveillance screening. (a) Axial T2WI shows a large well defined mass at the right apex (arrows). (b) ADC map demonstrates the mass with low ADC value (arrows). (c) DCE shows the mass with rapid contrast wash-in and -out (red color) of the mass (arrows). (d) MRSI shows elevated choline peaks of the mass (arrows). Surgery confirmed PCa Gleason score 8.

Figure 2

A small prostate cancer Gleason score 6 at the right mid PZ in a patient for AS. (a) (a) Axial T2WI shows a small low T2 signal intensity lesion at the right mid (arrow). (b) ADC map demonstrates a small low ADC signal intensity lesion at the right mid (arrow). (c) DCE demonstrates a small lesion at the right mid with contrast wash in and out (arrow).

Figure 3

Small recurrence in the left prostate surgical bed in a patient status post radical prostatectomy with a recent elevation of PSA to 0.21ng/ml. (a) Axial T2WI shows a small mass with slightly high T2 signal (arrow) relative in the left prostate surgical bed. (b) DCE shows the lesion with rapid contrast wash-in and -out (arrow) consistent with a focal recurrence.

Figure 4

Small recurrence in the right seminal vesicle (confirmed by MRI guided biopsy) in a patient status post internal radiation seeds treatment with an elevation of PSA to 2.7 ng/ml. Focal salvage brachytherapy was performed later on. (a) Axial T2WI shows a small low T2 signal intensity lesion (arrow) in the right seminal vesicle (SV). (b) ADC map demonstrates a small low ADC signal intensity lesion (arrow) in the right seminal vesicle (SV). (c) DCE shows the lesion with rapid contrast wash-in and -out (arrow) in the right seminal vesicle (SV). (d) Axial T2WI shows the small low T2 signal intensity lesion (arrow) surrounded by radiation seeds (seeds) in the right seminal vesicle (SV). (e) ADC map demonstrates no diffusion restriction at the site of the lesion (arrow) in the right seminal vesicle (SV). (f) DCE shows the lesion with disappearance of abnormal contrast enhancement (arrow) in the right seminal vesicle (SV) after focal salvage brachytherapy.