Describe Carcinoma of the Prostate in detail.

The Concept

Carcinoma of the prostate is an adenocarcinoma that typically arises in the peripheral zone of the gland (in contrast to BPH, which affects the central transitional zone). It is one of the commonest cancers in older men and is characteristically androgen-dependent — a fact that underlies its hormonal treatment. Its peripheral location explains why it often causes few early symptoms and why it is felt as a nodule on rectal examination.

Risk Factors & Clinical Features

Risk rises with age, a family history, and African ethnicity. Because it starts peripherally, it is frequently asymptomatic early; later it may cause LUTS, and it may present with metastatic disease — classically bone pain and back pain from osteosclerotic spinal metastases, or with weight loss. On DRE the gland is hard, nodular and irregular with loss of the median sulcus.

Spread

Prostate cancer spreads locally (into the seminal vesicles and bladder base), by lymphatics (to pelvic nodes), and by blood to bone — producing characteristically osteosclerotic (osteoblastic) metastases, especially in the axial skeleton and spine (a cause of back pain and cord compression).

Investigation, Grading & Staging

Assessment uses serum PSA (raised) and DRE, followed by multiparametric MRI and TRUS- (or MRI-) guided biopsy. The biopsy is graded by the Gleason score (now expressed as grade groups), which reflects the architectural differentiation and strongly predicts behaviour. Staging (TNM) includes a bone scan (isotope) to detect skeletal metastases.

Management

• Localised disease — options are active surveillance (low-risk disease), radical prostatectomy, or radical radiotherapy (external beam or brachytherapy).
• Locally advanced disease — radiotherapy combined with hormonal therapy.
• Metastatic disease — androgen deprivation therapy (ADT) exploiting the tumour's hormone dependence: LHRH agonists (e.g. Goserelin), anti-androgens, or surgical orchidectomy, with chemotherapy and palliative measures (radiotherapy and bisphosphonates for bone pain).

The Psa Controversy

PSA deserves a nuanced note because it is imperfect. It is prostate-specific but not cancer-specific — it also rises with BPH, prostatitis, urinary infection, catheterisation and even DRE — so a raised PSA is not diagnostic and a normal one does not exclude cancer. This is why population screening with PSA is controversial: it detects many indolent cancers that would never have caused harm ('overdiagnosis'), leading to overtreatment. PSA is best used with DRE, MRI and biopsy in a shared decision, rather than as a standalone screening test.

Spinal Cord Compression — an Emergency

A crucial clinical scenario is metastatic spinal cord compression, since prostate cancer characteristically metastasises to the spine. New back pain with leg weakness, sensory change, or bladder/bowel dysfunction in a man with prostate cancer is an emergency requiring urgent MRI and treatment (high-dose steroids, radiotherapy or surgical decompression, plus androgen deprivation) to preserve neurological function. Recognising this prevents permanent paralysis.

Hormonal Therapy in Depth

Because the tumour is androgen-dependent, androgen deprivation therapy (ADT) is the cornerstone of advanced disease. This is achieved by surgical castration (bilateral orchidectomy) or, more commonly, medical castration with LHRH agonists (e.g. Goserelin) — which paradoxically cause an initial testosterone 'flare' (covered by an anti-androgen). ADT has significant side-effects (hot flushes, loss of libido, osteoporosis, metabolic effects), and cancers eventually become 'castration-resistant', requiring further agents — so treatment balances disease control against quality of life.

A Note on Prostatitis in the Differential

When assessing the prostate it is worth remembering prostatitis in the differential of a raised PSA and prostatic symptoms. Acute bacterial prostatitis causes fever, perineal/pelvic pain, LUTS and an exquisitely tender prostate on gentle DRE (vigorous examination or massage is avoided in the acute phase), and it can markedly elevate PSA. Recognising prostatitis prevents misinterpreting a transiently high PSA as cancer, and ensures the infection is treated with an appropriate prolonged course of antibiotics.

• Peripheral zone; DRE hard/nodular/irregular; PSA raised; graded by Gleason score (grade group).
• Osteosclerotic (osteoblastic) bone metastases — spine → back pain/cord compression; bone scan for staging.
• Metastatic disease → androgen deprivation therapy (LHRH agonist e.g. Goserelin, anti-androgen, or orchidectomy).

Osteoblastic (sclerotic) bone metastases are characteristic.

• Prostate adenocarcinoma arises in the peripheral zone; common in older men; androgen-dependent.
• Often asymptomatic early; later LUTS or metastatic bone/back pain; DRE hard, nodular, irregular, sulcus lost.
• Spreads locally, to nodes, and to bone (osteosclerotic metastases, axial skeleton/spine).
• PSA + DRE + mpMRI + TRUS biopsy (Gleason score/grade group); bone scan for skeletal staging.
• Localised: surveillance/radical prostatectomy/radiotherapy; metastatic: androgen deprivation (goserelin/orchidectomy) ± chemo.