5.1 Active Surveillance & Watchful Waiting

5.1 Active Surveillance & Watchful Waiting

The widespread implementation of serum prostate-specific antigen (PSA) screening led to a dramatic stage shift toward localized, screen-detected prostate cancer. However, this diagnostic migration also precipitated widespread overdiagnosis and overtreatment of clinically indolent, low-risk tumors that pose negligible lifetime risk of metastasis or cancer-specific mortality. In response, modern urological practice incorporates two distinct conservative, observational management strategies: Active Surveillance (AS) and Watchful Waiting (WW). For the Fellow of the European Board of Urology (FEBU) examination, differentiating between these two modalities—their clinical intent, candidate selection criteria, surveillance intensity, and intervention thresholds—is essential.

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1. Conceptual Distinction: Curative vs Palliative Intent

Although both paradigms avoid immediate invasive intervention at diagnosis, their fundamental clinical philosophies, monitoring protocols, and clinical outcomes differ radically:

Active Surveillance (AS)

• Primary Intent: Strictly curative.
• Objective: To monitor low-risk, organ-confined disease proactively with serial biomarkers, imaging, and re-biopsies. The goal is to safely delay or avoid the urinary, sexual, and bowel toxicities of radical intervention without forfeiting the therapeutic window for definitive cure if clinically significant progression is confirmed.
• Target Population: Men with localized, low-risk (and highly selected favourable intermediate-risk) prostate cancer, good functional status, and a substantial life expectancy (typically >10 to 15 years).
• Follow-up Protocol: Structured, intensive, and proactive, incorporating regular PSA measurements, annual clinical examinations, serial multiparametric MRI (mpMRI), and systematic/targeted restaging biopsies.
• Treatment Trigger: Biopsy-confirmed progression beyond appropriate AS criteria, particularly Grade Group ≥3, cribriform/intraductal histology, or substantial disease extent; selected low-volume GG2 does not automatically require treatment.

Watchful Waiting (WW)

• Primary Intent: Strictly palliative.
• Objective: To minimize treatment burden when competing mortality limits the benefit of cure. Palliative treatment addresses symptomatic local progression (e.g., obstruction or haematuria), metastatic symptoms, or progression judged imminent.
• Target Population: Asymptomatic patients unsuitable for curative treatment because of limited life expectancy, usually <10 years, frailty or major comorbidity; WW can apply across localized-disease risk groups.
• Follow-up Protocol: Individualized and usually symptom-focused. Annual or six-monthly PSA can help in higher-risk disease, with examination or imaging if progression is suspected. Routine AS-style restaging biopsies are not required.
• Treatment Trigger: Symptomatic or imminent progression, using appropriate palliation such as TURP for obstruction, ADT for progressing disease or radiotherapy for painful bone metastases.

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2. EAU Eligibility Criteria for Active Surveillance

EAU recommends AS as standard care for suitable men with low-risk disease and recognizes selected favourable intermediate-risk candidates. Selection combines pathology, PSA, examination, MRI and biopsy extent. Cohort protocols such as PRIAS, Johns Hopkins and Toronto differ; their entry thresholds are not universal EAU requirements.

Common Selection Features

• Histopathological Grade: ISUP Grade Group 1 (Gleason 3 + 3 = 6) is the usual starting group. Selected low-volume GG2 may also qualify; GG3 is excluded.
• PSA and Clinical Stage: Classic cohorts commonly use PSA <10 ng/mL and cT1c–cT2a. Clinical T-stage is based on DRE; MRI findings are reported separately.
• Biopsy Tumour Volume: Assess the number and involvement of positive systematic cores together with MRI lesion extent. There is no universal GG1 limit of two or three positive cores. Multiple targeted cores from one lesion do not independently measure whole-gland tumour volume.
• PSA Density: A low PSAD is reassuring, and <0.15 ng/mL/cc is a commonly used threshold. Higher PSAD increases concern but does not itself diagnose an unsampled high-grade anterior or apical cancer.
• MRI and Sampling: Review MRI for disease extent and ensure suspicious lesions have been adequately sampled. MRI suspicion alone does not establish grade; extraprostatic or seminal-vesicle involvement is incompatible with routine localized-disease AS selection.

Selected Favourable Intermediate-Risk Disease

EAU gives a weak recommendation to offer AS to selected GG2 patients, for example <10% pattern 4, PSA <10 ng/mL, ≤cT2a, low MRI extent and low biopsy extent (≤3 GG2-positive cores, ≤50% involvement per core), without cribriform or intraductal histology. Discuss the increased metastatic-progression risk. These systematic-biopsy limits must not be applied as a count of repeated targeted cores from the same lesion.

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3. Longitudinal Monitoring Protocol & Modalities

Once a patient is enrolled in an active surveillance program, rigorous serial monitoring is mandated to detect occult undersampling (sampling error on initial biopsy) or true biological clonal progression.

Standard Surveillance Schedule

1. PSA Kinetics & Serum Monitoring:
   • Total PSA measurement every 3 to 6 months.
   • PSA doubling time (PSADT) and PSA velocity are monitored. A rising PSA with PSADT <3 years prompts MRI and repeat biopsy. PSA change alone does not justify radical treatment; base a treatment change on biopsy progression.
2. Digital Rectal Examination (DRE):
   • Performed every 6 to 12 months to identify palpable progression to cT2b, cT2c, or cT3 disease.
3. Multiparametric MRI (mpMRI):
   • Repeat MRI according to risk and the biopsy schedule, and when PSA or clinical findings raise concern. EAU does not prescribe one universal 12–18-month then 2–3-year MRI schedule.
   • PRECISE (Prostate Cancer Radiological Estimation of Change in Sequential Evaluation) scores serial MRI change from 1 to 5. MRI progression prompts biopsy confirmation before a treatment change.
4. Confirmatory & Surveillance Biopsies:
   • Confirmatory Biopsy: If the initial systematic biopsy was performed without MRI, obtain MRI before confirmatory sampling, generally within 6–12 months. EAU weakly recommends omitting confirmatory biopsy after upfront MRI with targeted/perilesional sampling; it is not mandatory for every patient.
   • Repeat Sampling: Take targeted and perilesional cores from PI-RADS ≥3 lesions. Systematic cores can add information about more widespread disease. If MRI is unavailable, retain protocol-based confirmatory biopsy.
   • Serial Biopsy: Generally every 2–3 years until life expectancy falls below 10 years, rather than stopping automatically at age 75. Stable low-risk disease, stable MRI (PRECISE 3) and stable PSAD <0.15 may justify omission of repeat biopsy under a weak EAU recommendation; stable MRI alone does not replace biopsy.

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4. Criteria for Switching to Active Curative Intervention

The decision to change from AS to radical prostatectomy or radiotherapy considers biopsy findings, disease extent, life expectancy and patient preference:

• Histopathological Progression: GG≥3 is a strong reason to leave AS. An upgrade to low-volume GG2 alone is not a definitive reason to stop, particularly when found on targeted biopsy; reassess whether favourable selection criteria remain satisfied.
• Adverse Morphology: Cribriform adenocarcinoma or intraductal carcinoma on biopsy excludes continued AS.
• Increasing Extent: Reclassify initially low-volume GG2 when repeat non-MRI systematic biopsy shows >3 positive cores or >50% involvement per core. Targeted positive-core count alone is not a volume threshold.
• MRI or Clinical Change: New MRI progression, including suspected extraprostatic or seminal-vesicle involvement, or a changing DRE requires reassessment and biopsy. Report MRI staging separately from DRE-based clinical T-stage; do not switch treatment on MRI, PSA or DRE change alone.
• Patient Preference and Anxiety: Persistent anxiety can justify active treatment after shared decision-making; psychological support is another option. Approximately 10% experience anxiety during AS, which is not the same as a 10% discontinuation rate.

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5. Comparative Management Framework