Radiology: Imaging Cancer
Radiology: Imaging Cancer
Multiparametric MRI before and after Focal Therapy for Prostate Cancer: Pearls and Pitfalls for the Reporting Radiologist
Oncologic Basis of Focal Therapy
Oncologic Basis of Focal Therapy
Whole-gland treatment approaches such as radical prostatectomy and radiation therapy have long been regarded as the reference standard of definitive treatment of prostate cancer, with robust long-term oncologic outcome data. However, these interventions are associated with substantial morbidities, including urinary incontinence and erectile dysfunction.
To reduce overtreatment of prostate cancer, active surveillance was introduced two decades ago, where patients with low-risk or favorable intermediate-risk disease are closely monitored and undergo definitive treatment only when more aggressive disease manifests. While active surveillance is a reasonable option for low-grade, localized cancers, controversy remains over whether patients with intermediate-risk disease are suitable candidates. Besides the risk of progressive disease, active surveillance is disadvantageous, as patients are subjected to frequent follow-up visits, repeat imaging and biopsies, and anxiety and financial strain.
Consequently, various focal therapy options have been explored in an attempt to find a middle ground between whole-gland therapy and active surveillance. Considerable evidence suggests that although prostate cancer is often multifocal, it is the pathologic characteristics of the largest or most aggressive cancer focus (index lesion) that determines tumor progression and metastasis risk. It may therefore be sufficient to treat the index lesion and adopt active surveillance for the remaining low-risk lesions. The challenge of focal therapy is to improve quality of life without jeopardizing oncologic control and to focus treatment on the tumor while minimizing injury to the rest of the prostate, particularly the neurovascular bundles, bladder neck, and urethral sphincter.
Due to the paucity of reliable evidence on long-term efficacy and lack of randomized trials supporting these emerging treatment strategies, current European Association of Urology and American Urological Association guidelines recommend focal therapy to be performed only in experienced centers within the context of a clinical trial or a well-designed prospective cohort study. However, short- and intermediate-term clinical data have shown promising oncologic and functional outcomes, supporting these strategies as potential standard-of-care options. These techniques have garnered much interest and have been fast gaining popularity among physicians and patients.