Marieke van Son

164 CHAPTER 9 Case Presentation A 77-year-old male visited the radiation oncology department for a follow-up consul- tation nine years after initial prostate cancer treatment with whole-gland Iodine-125 brachytherapy (145Gy). His further medical history consisted of an asymptomatic tho- racic aortic aneurysm and his medication included antihypertensive drugs, a choles- terol-lowering statin, and an anticoagulant. The initial cT1ciT2aNxMx prostate tumor (staged on MRI) was located in the left peripheral zone (initial prostate-specific antigen (PSA) 7.9 ng/ml). Treatment-related toxicity involved increased urinary frequency and transient obstructive complaints for which he received tamsulosin 0.4 mg once daily for approximately 18 months post-implantation. His erectile function declined but was sufficient for penetrative intercourse without the need for supporting medication. PSA levels dropped to a nadir of 0.2 ng/ml one year after treatment and remained stable during the first three years of follow-up. Later, a steady upward trend was seen with a PSA doubling time (PSADT) of 12 months up to the level of 2.5 ng/ml seven years posttreatment. This was considered a biochemical recurrence according to the Phoenix definition (PSA nadir+2 ng/ml) and radiographic evaluation for recurrent disease was performed using 3T multiparametric-MRI (mp-MRI) and F18-Choline PET-CT. However, there were no signs of local recurrence or distant metastases, nor on repeat imaging one year later. When the patient returned to our department, the PSA level had further increased to 6.7 ng/ml (prostate-specific antigen doubling time (PSADT) 18 months) and a 68Ga-PS- MA PET-CT followed. The scan revealed local high uptake in the right dorsal peripheral zone next to the prostate midline and in the right seminal vesicle (Figure 1). A 3T mp-MRI (Figure 2) and MRI-guided target biopsies confirmed this lesion (25% adenocarcino- ma in one out of two cores, suggested Gleason score 4+3=7). Upon this, the patient was treated with MRI-guided focal salvage high-dose-rate brachytherapy (HDR-BT).