Prostate cancer is a disease of men. An estimated 1.2 million cases were diagnosed in 2018, making it the second most commonly diagnosed cancer in men worldwide. It was also the most common cancer in men aged over 55. In the same year, prostate cancer was the third most common cause of cancer-related death in men in North America and Europe. From a global perspective, deaths from liver, stomach, and esophageal cancer meant that it ranked sixth for cancer deaths internationally.
The prostate is a small glandular organ (typically 20-30 g in the healthy adult male) responsible for producing most seminal fluid. It lies anterior to the rectum and encases the urethra between the bladder neck and the external urethral sphincter. The "nervi erigentes" (responsible for continence and erectile function) course from the hypogastric plexus and lie in intimate relation to its postero-lateral surfaces. These relationships are critical when considering the likely adverse events following any treatment for prostate cancer. The zonal anatomy of the prostate was described by McNeal in 1968 and remains in use today, with around 70% to 80% of cancers developing in the peripheral zone and cancer seldom found in the central zone.
The American Joint Committee on Cancer (AJCC) tumor, node, metastasis (TNM) 2018 staging classification for prostate cancer is shown in the table (see Table. Localized Prostate Cancer Staging Guidelines, Tumor). Local invasion is to surrounding structures such as seminal vesicles, bladder, and rectum. Metastasis most commonly occurs via a lymphatic route to pelvic and para-aortic lymph nodes and a hematogenous route to the bone. Visceral metastasis to the lung, liver, and other organs is relatively rare and associated with unusual pathology and a poor prognosis.
In clinical practice, prostate cancer is most conveniently categorized as:
Localized prostate cancer: T1/2/ early T3, N0, M0
Locally advanced prostate cancer: Established T3 or T4, N0/1, M0
Metastatic cancer: M1 disease
In this topic, localized prostate cancer includes cases of early T3 prostate cancer, either on the investigation (eg, transrectal ultrasound [TRUS], MRI) or on final pathology (eg, following radical prostatectomy). The natural history of prostate cancer has been extensively studied in patients treated conservatively. Most localized prostate cancer represents an indolent disease, with population studies indicating slow progression in the majority over many years.
Men with low-grade tumors rarely die from prostate cancer. They are much more likely to die from other causes first. On the other hand, men with high-grade disease are more likely to die from prostate cancer within ten years without radical treatment. The prognosis of men with intermediate-risk cancer is the most difficult to predict. The perceived increased risk of mortality compared to low-risk disease can often push clinicians towards radical treatment in these cases. Still, such a strategy has been challenged by the findings of studies such as the ProtecT study of treatments for localized prostate cancer. Prognostic markers and scoring will likely be of great interest to this group of patients.
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