Oncology · Genitourinary Malignancies
The facts most likely to be tested
Prostate cancer most commonly arises in the peripheral zone of the prostate, making it palpable on digital rectal exam (DRE) as a hard, nodular, or irregular mass.
Prostate-specific antigen (PSA) is a sensitive but non-specific screening tool that can be elevated in benign prostatic hyperplasia (BPH), prostatitis, and prostate cancer.
The definitive diagnosis of prostate cancer is established via transrectal ultrasound (TRUS)-guided needle biopsy showing adenocarcinoma with a Gleason score used for histologic grading.
Prostate cancer frequently metastasizes to the axial skeleton (lumbar spine and pelvis) via the Batson venous plexus, often presenting as osteoblastic (sclerotic) lesions.
Patients with metastatic prostate cancer typically present with bone pain or pathologic fractures and may show elevated alkaline phosphatase levels due to increased osteoblastic activity.
Initial management for localized, low-risk prostate cancer often involves active surveillance to avoid the morbidity of radical prostatectomy or radiation therapy.
Advanced or metastatic prostate cancer is treated with androgen deprivation therapy (ADT), such as leuprolide (a GnRH agonist) or flutamide (an androgen receptor antagonist).
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A 72-year-old male presents to the clinic complaining of worsening lower back pain and nocturia over the past three months. On physical examination, a hard, fixed, irregular nodule is palpated on the posterior aspect of the prostate. Laboratory studies reveal an elevated PSA of 14 ng/mL and an elevated alkaline phosphatase. A plain film radiograph of the lumbar spine demonstrates multiple sclerotic lesions.
What is the most appropriate next step to confirm the diagnosis?
Transrectal ultrasound (TRUS)-guided needle biopsy
The patient's clinical presentation of a hard prostate nodule and sclerotic bone lesions is highly suggestive of metastatic prostate cancer; a biopsy is required to confirm the diagnosis and determine the Gleason score.
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Etiology / Epidemiology
Most common non-cutaneous cancer in men; age > 65, African American race, and family history are primary risk factors.
Clinical Manifestations
Often asymptomatic; advanced disease presents with obstructive voiding symptoms or bone pain from metastatic spread.
Diagnosis
Diagnosis requires prostate biopsy; screening involves PSA > 4.0 ng/mL and digital rectal exam findings.
Treatment
Localized disease managed with radical prostatectomy or radiation therapy; advanced disease requires androgen deprivation therapy.
Prognosis
High 5-year survival for localized disease; spinal cord compression is a critical late-stage complication.
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Epidemiology & Etiology
Incidence increases sharply with age, with the majority of cases diagnosed in men over 65. African American men exhibit higher incidence and mortality rates compared to other ethnicities. A strong family history (first-degree relative) significantly elevates individual risk.
Pertinent Anatomy
Prostate cancer predominantly arises in the peripheral zone, which is why early lesions are often palpable on digital rectal exam. In contrast, benign prostatic hyperplasia typically originates in the transition zone surrounding the urethra.
Pathophysiology
Most cases are adenocarcinomas driven by androgen-dependent growth. Metastasis occurs primarily via hematogenous spread to the axial skeleton, specifically the lumbar spine and pelvis, often resulting in osteoblastic lesions. Progression is graded using the Gleason score, which correlates with tumor aggressiveness.
Clinical Manifestations
Early-stage disease is typically asymptomatic. Advanced cases present with urinary retention, hematuria, or nocturia. Bone pain or pathologic fractures suggest metastatic disease, while cauda equina syndrome indicates an oncologic emergency.
Diagnosis
Screening utilizes PSA levels and digital rectal exam (DRE). A PSA > 4.0 ng/mL or abnormal DRE (nodules, induration) warrants a transrectal ultrasound-guided biopsy. The Gleason score is the definitive histologic grading system used for prognosis.
Treatment
Localized disease is treated with radical prostatectomy or external beam radiation. Advanced or metastatic disease requires androgen deprivation therapy (e.g., leuprolide). Orchiectomy is an alternative for surgical castration. Flutamide is often added to prevent the initial testosterone flare.
Prognosis
Prognosis is excellent for localized disease but poor once distant metastases occur. Bone metastases are the most common cause of morbidity. Patients require serial PSA monitoring to detect biochemical recurrence.
Differential Diagnosis
Benign Prostatic Hyperplasia: typically involves the transition zone and lacks malignant nodules
Prostatitis: presents with fever, dysuria, and a tender, boggy prostate
Prostatic Abscess: presents with severe pain and fluctuance on exam
Urethral Stricture: presents with obstructive symptoms but no prostate nodules
Bladder Cancer: presents with painless gross hematuria