The Prostate Testing for Cancer and Treatment (ProtecT) trial provides extensive long-term data on managing localized prostate cancer. It was initiated due to uncertainty over the best treatment approach for cancer confined to the prostate gland. The study’s findings have since offered clarity, shaping contemporary care for one of the most common cancers in men.
The ProtecT Trial’s Design
The ProtecT trial was a large-scale, randomized controlled trial conducted across the United Kingdom between 1999 and 2009. It involved 82,429 men aged 50 to 69 who had a prostate-specific antigen (PSA) blood test. From this group, 1,643 men diagnosed with localized prostate cancer were randomly assigned to one of three management strategies.
The three trial groups represented the main treatment options. One group was assigned to active monitoring, involving regular PSA tests to track the cancer’s status with an option for radical treatment if it progressed. The second group underwent radical prostatectomy, the surgical removal of the prostate gland. The third group received external-beam radiotherapy to destroy cancer cells, often preceded by short-term hormone therapy.
The trial was designed to directly compare the long-term effectiveness and side effects of these different approaches. Its goal was to determine if one treatment offered a better chance of survival from prostate cancer.
Key Survival and Progression Findings
After an average follow-up of 15 years, the trial showed that death from prostate cancer was very low regardless of the initial treatment. The mortality rate was not significantly different between active monitoring (3.1%), surgery (2.2%), and radiotherapy (2.9%). Overall survival from prostate cancer was approximately 97% across all groups, showing the initial treatment choice had little effect on this outcome.
While survival rates were similar, the trial found differences in disease progression and metastasis (the spread of cancer). The active monitoring group had a higher incidence of metastasis (9.4%) compared to the surgery (4.7%) and radiotherapy (5.0%) groups. This shows that active monitoring was associated with a greater likelihood of the cancer advancing beyond the prostate.
Local progression, where the cancer grew but stayed in the pelvic region, was also more common in the active monitoring group (25.9%) than the prostatectomy (10.5%) and radiotherapy (11.0%) groups. Men in the active monitoring arm were therefore more likely to eventually receive long-term androgen-deprivation therapy. However, the development of metastatic disease did not automatically lead to death, as many of these men survived for years after the cancer had spread.
Comparing Treatment Side Effects
The ProtecT trial tracked quality-of-life outcomes, revealing distinct side effect profiles for each treatment. Using annual questionnaires for over a decade, the study focused on patient-reported urinary, bowel, and sexual function. These differences highlight the trade-offs patients face when making treatment decisions.
Men who underwent radical prostatectomy experienced the most persistent side effects related to urinary and sexual function. Urinary incontinence, specifically needing to wear pads, was much more common in the surgery group. Difficulties achieving and maintaining an erection were also more frequently reported by this group. While some issues improved after six months, they remained more prevalent long-term.
The radiotherapy group reported different side effects, primarily impacting bowel function. Six months post-treatment, these men experienced more bowel problems like rectal bleeding and fecal urgency. While many symptoms lessened over the next few years, some men experienced increasing bowel issues long-term.
Men on active monitoring initially avoided the side effects of radical treatments. However, over the 15-year follow-up, about 61% eventually transitioned to surgery or radiotherapy. At that point, they then faced the side effects associated with those interventions.
Implications for Modern Prostate Cancer Treatment
The ProtecT trial’s results have validated active monitoring as a primary management strategy for many men with localized prostate cancer. Since survival rates at 15 years were nearly identical regardless of the path taken, the findings support a less urgent approach to treatment decisions. This allows patients to carefully weigh the potential for treatment-related side effects.
The trial highlights the importance of shared decision-making between a patient and their clinical team. The choice of therapy involves balancing the reduced risk of cancer progression against the quality-of-life side effects. Patients can be assured that choosing active monitoring initially is unlikely to affect their long-term survival, empowering them to choose based on personal priorities.
The evidence from ProtecT supports giving men time to understand the different outcomes associated with each approach. While the surgical and radiotherapy techniques used in the trial have evolved, subsequent studies show that modern methods carry similar side effect profiles. This makes the ProtecT findings relevant for today’s patients and supports a more patient-centered approach to care.