The negative ANSA-RAD trial, when contrasted with the positive STAMPEDE trial, demonstrates that patient selection is paramount in adjuvant therapy. The difference in outcomes was driven by risk definition, not the drug. This reinforces that "negative" trials are clinically vital for defining which patient populations do not benefit, preventing widespread overtreatment.

The debate over the STAMPEDE and ENSA-RAD trials stems from a misunderstanding. They aren't contradictory but study different cohorts within the "high-risk" category. STAMPEDE focused on the highest-risk patients, while ENSA-RAD included a broader group. Combining their data could provide a more nuanced treatment approach.

Early neoadjuvant trials in the 1990s failed to show clinical benefit because they included many low-risk patients and used less potent hormonal therapies. The PROTEUS trial's success was built on learning from this history by strictly enrolling high-risk patients and using a powerful androgen receptor pathway inhibitor (ARPI).

The impressive 68% pathological complete response (pCR) in the SAKK neoadjuvant bladder cancer study may be misleading. Such high rates in single-arm trials are often driven by patient selection biases, such as enrolling patients with earlier T2 disease and those who've had thorough initial surgeries.

The Proteus trial's requirement of 2,000 patients highlights a fundamental issue in adjuvant therapy: to prove a modest benefit, a vast number of patients who may already be cured by surgery must be treated. This means many participants endure toxic therapy with no personal benefit, raising ethical concerns.

Even when testing drugs in heavily pre-treated patients, clinical trials incorporate subtle biological selection criteria. For instance, the COMPASS trial excludes patients with visceral metastases, a tactic to enrich for a population more likely to respond and avoid the most aggressive disease subtypes.

Registrational clinical trials for prostate cancer drugs enroll patients who are substantially younger (median age 67-69) and healthier than the typical real-world patient (median age 73-74). This gap means trial data on efficacy and safety doesn't perfectly apply to the majority of patients seen in clinic.

The clinical definition of "high-risk" prostate cancer is evolving due to improved diagnostics. The move from digital rectal exams to more sensitive MRI for T-staging means more patients meet the criteria for being high-risk. This "stage migration" makes it challenging to apply findings from older clinical trials to a contemporary patient population.

The definition of high-volume disease, a key factor in chemotherapy decisions for prostate cancer, has changed across major trials like CHARTERED and STAMPEDE. This evolution, including variations in bone metastases counts and inclusion of Gleason score, complicates cross-trial analysis and highlights its weakness as a surrogate for true disease biology.