Elsevier

Urology

Volume 85, Issue 6, June 2015, Pages 1224-1228
Urology

Review Article
Tumors of the Anterior Prostate: Implications for Diagnosis and Treatment

https://doi.org/10.1016/j.urology.2014.12.035Get rights and content

Tumors of the anterior prostate (ie, the portion of the prostate anterior to the urethra) account for approximately 20% of all prostate cancers. Although anterior prostate cancers frequently occur, they have historically been underdetected because of infrequent sampling. Recent advances in multiparametric magnetic resonance imaging and improved biopsy schemes have significantly increased our diagnostic accuracy for detecting anterior tumors. Herein, we review these developments and highlight key aspects of the diagnosis and management of anterior prostate cancers.

Section snippets

Prostate Anatomy

Our current understanding of prostate anatomy is largely based on the seminal work of McNeal. He demonstrated that the human prostate is a composite organ, made up of a nonglandular region, the anterior fibromuscular stroma (AFMS), and 3 distinct glandular zones: (1) the peripheral zone (PZ), (2) the central zone, and (3) the transition zone (TZ; Fig. 1).2

Location and Relevance

The majority of prostate tumors are located posteriorly in the PZ.4, 5 In the remaining cases, tumors are located anteriorly, in the anterior horn of the PZ, the AFMS, or the anterior portion of the TZ. These regions are usually nonpalpable on digital rectal examination (Fig. 2).

In a series of 224 men who underwent radical prostatectomy (RP), 71% of the nonpalpable tumors in the apex of the prostate were located anteriorly.6 Likewise, among 259 patients who underwent RP with exclusively

Prostate Biopsy Schemes

Until the 1980s, transperineal biopsy performed under digital guidance was the predominant method of prostate cancer diagnosis. Introduction of serum prostate-specific antigen (PSA) testing in the 1990s mandated a prostate biopsy in men with an elevated value despite a normal digital rectal examination, using a systematic sampling scheme.11 Initially, biopsies in this era were taken according to the Stamey protocol,12 in which samples were obtained in the midparasagittal plane at the base, mid,

Anterior Prostate Sampling

When using the traditional sextant scheme, anterior tumors are more difficult to detect than posterior tumors. In a series of 547 RP specimens, carcinoma was located predominantly anterior to the urethra in 21% of the specimens.17 In this series, patients who had anterior tumors were significantly more likely to require >1 set of sextant biopsies to diagnose malignancy compared with those with posterior tumors. Wright and Ellis18 showed early on that anterior apical prostate biopsies enhanced

Implications for Active Surveillance

Tumors of the anterior prostate present a special challenge to the management of patients on active surveillance (AS). Duffield et al23 endeavored to characterize disease progression in patients in whom AS failed. Of 470 men on AS, 48 (10%) had progressed and underwent RP, within an average time of 29.5 months after diagnosis. Analysis of the prostatectomy specimens in this subset of men determined that 27% were clinically insignificant according to the Epstein criteria. However, among this

Multiparametric Magnetic Resonance Imaging of the Prostate—the Gold Standard

mpMRI (T1- and T2-weighted imaging, diffusion-weighted imaging with apparent diffusion coefficient mapping, and dynamic contrast enhancement) is the preferred study for imaging prostate cancer and to aid in targeted biopsy of suspicious lesions. Targeted biopsy, via various techniques, has been demonstrated to be an efficient and effective method to detect clinically significant prostate cancer.25, 26, 27, 28, 29 Importantly, mpMRI performs best for the detection of clinically significant

Implications for Radical Prostatectomy

The prostatic apex poses a special challenge at RP because of its variable morphology, presence of the dorsal venous complex, and lack of a true capsule.37 These anatomic issues contribute to the higher positive surgical margin rate regularly seen in this region of the prostate at RP. Godoy et al38 found an overall 9.8% positive margin rate among 1308 consecutive RP specimen, with 25.8% of these occurring at the apex or anteriorly. Positive margins in these locations also translated to worse

Conclusion

Anterior prostate cancer remains an undervalued entity despite its frequent occurrence. Anterior apical cores should be integrated into standard biopsy templates at initial biopsy. Men with a prior negative biopsy in whom there is high clinical suspicion should undergo mpMRI with subsequent targeted biopsy. For men who elect AS or require definitive treatment, knowledge of APC can provide meaningful information, which may alter management.

References (40)

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Financial Disclosure: The authors declare that they have no relevant financial interests.

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