Active surveillance

1. The clinical problem

Prostate cancer shows marked biological heterogeneity. Not all tumors diagnosed during a patient's lifetime will produce symptoms, metastases or cancer-specific mortality.

At the same time, radical treatments can have significant consequences for urinary continence, sexual function, urinary function and quality of life.

2. Before the tumor: evaluate the patient

Before deciding on a treatment strategy we must consider life expectancy. Knowing chronological age is not enough: we must integrate age, comorbidities, functional status, cardiovascular disease, other malignancies, frailty and estimated life expectancy.

The importance of comorbidities is reflected in long-term follow-up studies: in older patients with a significant comorbidity burden, mortality from other causes can far exceed prostate cancer-specific mortality.

3. Two strategies that should not be confused

Active surveillance. The patient has a potentially curable disease. We decide not to treat now, but we maintain curative intent. We perform protocol-based follow-up to detect reclassification or progression and offer curative treatment when appropriate.

Watchful waiting. The intent is different. It is used mainly when the benefit of curative treatment is unlikely because of limited life expectancy, age, comorbidities or the patient's general characteristics. The goal is to avoid the adverse effects of unnecessary treatment and to start palliative treatment when symptomatic progression appears or is imminent.

4. Active surveillance vs. watchful waiting

	Active surveillance	Watchful waiting
Intent	Deferred curative	Palliative
Patient	Adequate life expectancy	Limited life expectancy
Disease	Mainly low risk and selected intermediate risk	Can apply to different risk levels depending on the patient
Follow-up	Protocol-based	Less intensive
PSA	Yes	May be used
MRI	Part of contemporary follow-up	Not necessarily
Repeat biopsies	Yes	Generally not
Trigger	Reclassification/progression	Symptoms/clinical progression
Subsequent treatment	Curative	Palliative

5. What is the goal of active surveillance?

The goal is to avoid unnecessary treatment in patients with localized cancer who do not require immediate treatment, while preserving the possibility of delivering curative therapy at the right time.

6. Who is the ideal candidate?

The classic candidate is a low-risk prostate cancer, with:

• Localized disease.
• Low Grade Group.
• Favorable PSA.
• Low tumor burden.
• No adverse histology.
• Sufficient life expectancy to benefit from deferred treatment if progression were to appear.

Active surveillance is a first-line strategy for appropriately selected patients with low-risk disease.

7. Can we monitor a Grade Group 2?

Yes, in highly selected patients. This is an important concept for the resident: active surveillance should no longer be understood exclusively as "GG1 = surveillance, GG2 = treatment." Some patients with favorable intermediate risk may be candidates after careful evaluation, but they must be informed that they have a higher probability of progression/reclassification than classic low-risk patients.

8. PRIAS criteria

The PRIAS protocol is a fundamental historical and clinical reference in active surveillance. Among the criteria included in the teaching material:

• Stage: cT ≤ 2.
• Grade Group: ISUP GG1, or selected GG2.
• PSA: ≤ 20 ng/mL.
• PSA density: < 0.25 ng/mL/cc.
• Tumor volume: in GG1 there may be greater flexibility in the number of cores; in GG2 the tumor burden must be limited. In MRI-targeted biopsies, cores from the same lesion must be interpreted considering that they represent a single focus.

9. Histology that should concern us

There are two especially important findings: cribriform pattern and intraductal carcinoma. Their presence identifies a less favorable biology.

10. Tumor burden matters

The decision does not depend solely on Grade Group. We must also consider:

• Number of positive cores.
• Percentage of involvement.
• Tumor extent.
• Amount of pattern 4.
• Number and characteristics of MRI lesions.
• PSA density.

In selected GG2, a high disease burden reduces suitability for active surveillance.

11. PSA density

PSAD = PSA / prostate volume.

PSA density adds information that PSA alone cannot provide. A rising or elevated density must be interpreted together with MRI, histology, tumor burden and PSA kinetics — never in isolation.

12. Role of magnetic resonance imaging

Multiparametric MRI profoundly changed contemporary active surveillance. It improves initial selection, identifies significant lesions not previously detected, guides biopsies and assesses changes during follow-up.

13. Importance of the initial biopsy

The quality of the biopsy with which we enroll the patient in surveillance is fundamental. If the initial evaluation underestimates the disease, the problem is not that the tumor has "progressed" rapidly: it may be an initial sampling error.

That is why modern enrollment must integrate: PSA + PSAD + MRI + adequate biopsy + pathology.

14. Follow-up

According to the EAU scheme presented in the material: PSA at least every 6 months, digital rectal exam at periodic clinical follow-up, and repeat biopsy with or without MRI according to protocol and context, usually within protocol-based schedules every few years.

Follow-up continues as long as life expectancy is sufficient for detecting progression to change management. The teaching material summarizes the EAU 2026 recommendation as PSA at least every six months, digital rectal exam and repeat biopsy with or without MRI every 2–3 years until life expectancy falls below approximately ten years.

15. The PRIAS example

PRIAS used an intensive follow-up protocol: periodic PSA, digital rectal exam, clinical evaluations, MRI, targeted biopsies and scheduled systematic biopsies. The teaching material presents PSA every 3 months, digital rectal exam every 6 months, and protocol-based biopsies/re-evaluations at entry and later during follow-up.

The message for the resident should not be to memorize a single schedule: it is to understand that active surveillance needs a protocol.

16. What do we do if PSA rises?

Suppose an initial PSA of 5.2, then 6.1, then 7.4, then 8.5. Should we automatically operate?

17. What if the MRI changes?

Example: initial MRI PI-RADS 3 stable; two years later, increase in size or greater radiological suspicion. Do we operate directly?

18. What really defines progression?

The most important information remains histological reclassification. During a follow-up biopsy we must look for an increase in Grade Group, the appearance of an adverse histological pattern or a relevant increase in tumor burden.

The teaching material identifies as findings that change the strategy: ISUP GG ≥ 3, or GG ≥ 2 with cribriform pattern or intraductal carcinoma, or GG ≥ 2 with a high burden of positive cores.

19. When to leave active surveillance?

The indication for active treatment should be based mainly on evidence that the disease no longer has the features for which we considered surveillance safe. We should reconsider treatment in the face of significant histological reclassification, and jointly weigh Grade Group, histological pattern, tumor burden, MRI, PSA/PSAD, stage, age, life expectancy and patient preferences.

20. Anxiety and active surveillance

There is another reason why some patients abandon surveillance: anxiety. The patient may say "I know I have cancer and I don't want to live with it." This should be discussed from the outset.

The evidence presented in the material shows that there may be initial anxiety, but many patients adapt and later have low levels of cancer-specific anxiety. Adequate information is part of the treatment.

21. Conversation with the patient

We should not say: "You have cancer, but we are not going to do anything."

Localized prostate cancer:

1. Assess life expectancy and comorbidities

• Limited life expectancy → consider watchful waiting.
• Adequate life expectancy → evaluate PSA + PSAD + cT + Grade Group + tumor burden + histology + MRI.

2. Low risk?

→ active surveillance, as the preferred strategy in appropriate patients.

3. GG2 / favorable intermediate risk?

Low volume? Little pattern 4? No cribriform? No intraductal carcinoma? Favorable MRI? Favorable PSAD? If the answer is yes across the board, selected active surveillance can be discussed.

4. Follow-up

Periodic PSA + clinical evaluation + MRI according to protocol/risk + repeat biopsies.

5. Is PSA changing?

Investigate, do not treat automatically → MRI / biopsy.

6. Significant histological reclassification?

→ consider active treatment.