What are the diagnostic steps for prostate cancer?

Prostate Cancer Diagnosis

Prostate cancer diagnosis requires a combination of PSA testing and digital rectal examination (DRE), followed by ultrasound-guided prostate biopsy for confirmation when these tests suggest cancer. 1

Initial Diagnostic Steps

1. PSA Testing and Digital Rectal Examination

   • Serum PSA measurement and DRE should be performed in patients presenting with urinary symptoms 2, 1
   • PSA risk stratification:
     • 0-2 ng/mL: ~1% risk of prostate cancer
     • 4-10 ng/mL: ~25% risk of prostate cancer

     • 10 ng/mL: >50% risk of prostate cancer 2, 1

   • DRE alone can detect significant cancers even when PSA is normal, with 20% of DRE-detected cancers having high Gleason scores (≥7) 3

2. Prostate Biopsy

   • Indicated when there is suspicion of clinically significant prostate cancer (abnormal DRE and/or elevated PSA) 2, 1
   • Should be performed under transrectal ultrasound (TRUS) guidance 2, 1
   • A minimum of 8-12 cores should be obtained 2, 1
   • Extended biopsy schemes (>6 cores) reduce false negative rates from 20% to 5% 1
   • Pathology report should include:
     • Extent of involvement of each core
     • Gleason score
     • Dominant and highest Gleason pattern 2, 1

Advanced Diagnostic Imaging

1. MRI

   • Multiparametric MRI is recommended before TRUS-guided biopsy to identify suspicious lesions for targeted sampling 1
   • Particularly valuable for patients with:
     • Prior negative biopsies but persistent suspicion
     • Patients on active surveillance 1, 4
   • Combines conventional and functional MRI techniques:
     • Diffusion-weighted imaging
     • Dynamic contrast-enhanced MRI
     • MR spectroscopy 4

2. Additional Imaging for Staging

   • Pelvic imaging (MRI or CT) should be performed before radical treatment when risk of nodal involvement exceeds 15% 2
   • Bone scintigraphy is indicated when:
     • Bone metastases are clinically suspected
     • Gleason score is >4+3
     • Serum PSA is >15 ng/mL 2

Special Considerations

1. Negative Biopsy with Persistent Suspicion

   • Consider PCA3 urine testing or repeat biopsy 1
   • Repeat biopsies detect cancer in 10-21% of patients with initially negative biopsies 1
   • MRI-targeted biopsies are recommended for patients with prior negative biopsies 1, 4

2. Biomarkers

   • Additional serum and urine biomarkers can aid in diagnosis:
     • Serum: 4K score, prostate health index (phi)
     • Urine: SelectMDx, ExoDx Prostate Intelliscore, MyProstateScore, PCA3 5
   • Free PSA measurement can help assess prostate cancer risk, especially when total PSA is 4-10 ng/mL 2

3. Biopsy Complications

   • Common complications include rectal or urinary hemorrhage, infection, and urinary retention 1
   • Most complications are transient and well-tolerated 1

Diagnostic Algorithm

1. Measure serum PSA and perform DRE in men with urinary symptoms
2. If PSA is elevated (>2.5-4.0 ng/mL) and/or DRE is abnormal, proceed to prostate biopsy
3. Perform TRUS-guided biopsy with a minimum of 8-12 cores
4. If biopsy is positive, perform risk stratification based on Gleason score, PSA level, and clinical stage
5. For high-risk patients, perform additional imaging (MRI/CT of pelvis, bone scan) for staging
6. If biopsy is negative but suspicion remains high, consider MRI-targeted biopsy or additional biomarker testing

This diagnostic approach ensures timely and accurate diagnosis of prostate cancer, which is crucial for appropriate treatment selection and improved patient outcomes.