Faculty Bibliography

PURPOSE: To compare boundaries of prostate tumors on MRI and histologic assessment from radical prostatectomy (RP) using detailed software-assisted co-registration, in order to define an optimal treatment margin to achieve complete tumor destruction during image-guided focal ablation. METHODS: 33 patients who underwent 3T MRI before RP were included. A radiologist traced lesion borders on MRI and assigned a suspicion score (SS) from 2-5. 3D reconstructions were created from high-resolution digitalized slides from RP specimens and co-registered to MRI using advanced software. Tumors were compared between histology and MRI using the Hausdorff Distance (HD) and stratified by MRI-SS, Gleason Score (GS), and lesion diameter. Cylindrical volume estimates of treatment effects were used to define the optimal treatment margin. RESULTS: 46 histologically confirmed cancers underwent 3D software-based registration with MRI. MRI underestimated tumor sizes, with the maximal discrepancy between MRI and histologic boundaries for a given tumor averaging 1.99+/-3.1mm (18.5% of the MRI diameter). Boundary underestimation was larger for MRI-SS>/=4 lesions (+3.49+/-2.1mm; p<0.001) and GS>/=7 lesions (+2.48+/-2.8mm; p 0.035). On average, a simulated cylindrical treatment volume based on the MRI boundary missed 14.8% of the tumor volume compared with a simulated cylindrical volume based on the histologic boundary. A simulated treatment volume based on a 9mm treatment margin achieved complete histologic tumor destruction in 100% of patients. CONCLUSION: MRI underestimates histologically-determined tumor boundaries, especially for high MRI-SS and high GS lesions. A 9mm treatment margin around an MRI-visible lesion consistently ensures treatment of the entire histologic tumor volume during focal ablative therapy.

PURPOSE: To evaluate the 6-month effects of the recommended drug and light dosage in focal vascular-targeted photodynamic therapy (VTP) using TOOKAD((R)) Soluble in patients with localized prostate cancer (LPCa). METHODS: We performed a pooled analysis of 117 men with LPCa, PSA <10 ng/mL, and Gleason score /= 1 (N = 67). Mean prostate necroses at week-1 were 76.5 and 86.3 %, respectively. In both groups, PSA levels at month 6 decreased by 2.0 ng/mL. Small changes from baseline for IPSS and IIEF-5 indicated a slight improvement in urinary function and a slight deterioration in sexual function. CONCLUSIONS: Focal VTP treatment with TOOKAD((R)) Soluble at 4 mg/kg and 200 J/cm resulted in a negative 6-month biopsy rate of 68.4 % for the whole population and 80.6 % for patients treated by hemiablation with LDI >/= 1. The treatment was well tolerated. Two phase III studies will reach completion in early 2015.

PURPOSE: In an era of increasing prostate cancer incidence and earlier detection, the assessment of clinical significance of prostate cancer is critical. Minimally invasive therapies are increasingly being investigated in localized prostate cancer. METHODS AND RESULTS: In this review, we discuss the current status of magnetic resonance imaging targeted fusion prostate biopsy and focal therapy for prostate cancer, its rationale, and techniques. CONCLUSION: Focal therapy offers a promising outlook for prostate cancer treatment, with the goal of effectively achieving cancer control while minimizing morbidity. Long term studies are needed.