Prostate cancer is one of the most frequently diagnosed cancers in men, but advances in detection have identified many tumors that are non-aggressive and grow very slowly. For men diagnosed with this specific form of the disease, a strategy of close monitoring, known as Active Surveillance (AS), has become the preferred management approach. This option allows individuals to defer intervention, avoiding the side effects of treatment until there is a confirmed need for it.
Defining Low-Risk Prostate Cancer
A prostate cancer diagnosis is categorized as low-risk only when specific diagnostic criteria are met, indicating the tumor is confined and non-aggressive. The most important factor is the tumor’s Grade Group, a modern system that has largely replaced the older Gleason Score for determining aggression.
Low-risk disease is defined by a Grade Group 1, which corresponds to a Gleason Score of 6 (3+3). This indicates that the cancer cells look very much like normal cells and are expected to be slow-growing.
The second criterion involves the Prostate-Specific Antigen (PSA) blood test, where the level must be less than 10 nanograms per milliliter (ng/mL). Finally, the cancer must be confined entirely within the prostate gland, known as localized disease (clinical stage T1 to T2a). Meeting all these criteria establishes a low-risk classification, making the patient a candidate for non-immediate treatment options.
Active Surveillance as the Primary Strategy
For individuals who meet the low-risk criteria, Active Surveillance (AS) is the recommended standard of care because it manages the risk without causing immediate harm. This strategy involves deliberately postponing definitive treatment, such as surgery or radiation, and instead monitoring the cancer closely for any signs of progression. The rationale for this approach is rooted in the understanding that many low-risk tumors are considered “clinically insignificant,” meaning they are unlikely to cause health problems during a man’s lifetime.
Immediate radical treatments like radical prostatectomy or radiation therapy carry a significant risk of side effects, including urinary incontinence and erectile dysfunction. By choosing Active Surveillance, men can avoid or delay these life-altering complications, maintaining their quality of life for as long as possible.
Long-term studies have demonstrated that for men with low-risk disease, Active Surveillance does not compromise the chance of a cure, with very low rates of cancer-specific death reported over a 10-to-15-year period. The goal is to only intervene if the cancer shows signs of becoming more aggressive, thereby preserving the curative potential of radical treatment for when it is truly needed.
The Monitoring Process
The successful implementation of Active Surveillance depends on a rigorous and consistent monitoring schedule to detect any change in the cancer’s status. The process typically involves regular PSA blood tests, which are performed every three to six months to track the protein’s level in the blood. A sudden or sustained rise in PSA may indicate that the cancer is growing more rapidly than expected.
Digital Rectal Exams (DREs) are also performed, often annually, allowing the physician to manually check for any new lumps or changes in the size or texture of the prostate. An increasingly important tool in the monitoring protocol is multi-parametric Magnetic Resonance Imaging (mpMRI), which provides detailed images of the prostate to identify suspicious areas. While the frequency varies, an mpMRI may be performed every two to three years and can help guide the placement of biopsy needles if a further tissue sample is required.
The most invasive part of monitoring is the repeat or surveillance biopsy, used to confirm the cancer’s low-risk status over time. Many protocols recommend a confirmatory biopsy within the first one to two years of diagnosis to ensure a higher-grade tumor was not missed initially. Subsequent biopsies may be scheduled every one to five years, though the need is often determined by changes in PSA level, DRE findings, or mpMRI results.
When Treatment Becomes Necessary
The transition from Active Surveillance to definitive treatment occurs when monitoring reveals evidence that the cancer is progressing beyond the low-risk threshold. The most common medical trigger is an increase in the tumor’s Grade Group, particularly a shift from Grade Group 1 (Gleason 6) to Grade Group 2 or higher (Gleason 7), which indicates the presence of more aggressive cancer cells.
Other signs of progression that may prompt a shift to treatment include the cancer growing outside the prostate (a higher clinical stage) or a rapid increase in the PSA level. In these situations, the patient and their doctor will discuss intervening with curative intent, typically involving a choice between radical prostatectomy or radiation therapy.
While medical progression is the primary reason for intervention, some men transition to treatment due to anxiety over living with a cancer diagnosis, demonstrating that the decision is also influenced by personal factors.