RADICALS-RT
After radical prostatectomy, does routine adjuvant radiotherapy improve outcomes compared with observation and early salvage radiotherapy triggered by PSA recurrence?
Main results
| Outcome | Adjuvant RT | Observation + early salvage RT | Relative effect |
|---|---|---|---|
| 5-y biochemical progression-free survival | 85% | 88% | HR 1.10 (95% CI 0.81–1.49), P=.56 |
| 5-y freedom from non-protocol hormone therapy | 93% | 92% | HR 0.88 (95% CI 0.58–1.33), P=.53 |
| 10-y freedom from distant metastases | 93% | 90% | HR 0.68 (95% CI 0.43–1.07), P=.095 |
| Overall survival | No improvement demonstrated | HR 0.98 (95% CI 0.67–1.44), P=.917 | |
Radiotherapy use: 93% of men allocated to adjuvant RT received RT within 6 months, whereas only 39% of men allocated to the salvage policy received RT during follow-up. Thus, the salvage-policy strategy avoided immediate RT for most men.
Absolute effects
5-year biochemical progression-free survival was 85% with adjuvant RT versus 88% with observation and early salvage RT. The difference was not statistically significant.
10-year freedom from distant metastases was 93% versus 90%; the hazard ratio did not reach statistical significance.
Toxicity / patient-reported outcomes
Urinary incontinence was worse at 1 year with adjuvant RT (mean score 4.8 vs 4.0, P=.0023). Grade 3–4 urethral stricture within 2 years occurred in 6% versus 4% (P=.020). Long-term follow-up continued to show worse urinary and faecal incontinence with adjuvant RT; faecal incontinence remained significantly worse at 10 years (P=.017).
Clinical interpretation
The initial 5-year analysis likewise showed no improvement in biochemical progression-free survival (85% vs 88%; HR 1.10, P=.56). Meanwhile, routine adjuvant RT exposed substantially more men to treatment and increased urinary and bowel morbidity. The trial therefore provides evidence for an observation policy with early salvage RT for men with adverse pathological features after prostatectomy, rather than routinely irradiating everyone.
NNT / NNH
No efficacy NNT is calculated because the 5-year biochemical endpoint numerically favoured the salvage policy and the 10-year metastasis endpoint was not statistically definitive. For grade 3–4 urethral stricture within 2 years, the absolute harm was 2 percentage points (6% vs 4%), giving NNH = 50 (based on grade 3–4 urethral stricture within 2 years). This is an observed toxicity difference and should not be interpreted as a composite measure of overall treatment burden.