Focal Therapy for Anterior Cancers

While finding a precise definition for anterior prostate cancer (APC) is challenging, in simplified terms, APCs are positioned anterior to the prostatic urethra in the mid-prostate transition zone (Fig. 25.1a). The dominant segment of the anterior prostate region is the transition zone (TZ), followed by the anterior fibromuscular stroma (AFMS) and anterior horns of the peripheral zone (PZ). Estimates suggest that APCs make up around 10–38% of total prostate cancer diagnoses, with the percentages increasing in more recent studies [2–5]. About 20% of APCs are palpable in digital rectal examination, and thus, they were historically underdiagnosed or usually diagnosed at a later stage compared to posterior tumors [6]. Due to the often late-stage diagnosis of APC, there is a higher incidence of positive surgical margins, incontinence, erectile dysfunction, and biochemical recurrence, even after undergoing radical prostatectomy [7, 8]. However, with the introduction of multiparametric MRI (mpMRI) and the latest reporting system (PIRADS version 2.1, which has improved performance for TZ tumors), there is a relatively higher potential for early-stage detection. APCs present an ideal opportunity for the application of focal therapy (FT) modalities in highly selected individuals, as the distant location from neurovascular bundles maximizes the chances of improved functional outcomes. Clinicians should tailor the treatment modality or energy source based on the size and location of the APC. This personalized approach, known as the “à la carte” model, helps in minimizing side effects. This chapter will discuss the histopathological features, clinical aspects, and diagnostic challenges of APCs, along with available focal treatment options and future directions.