RADICALS-RT

RADICALS-RT randomised 1,396 men in trial-accredited centres in Canada, Denmark, Ireland and the United Kingdom, 697 to adjuvant radiotherapy and 699 to an observation policy with salvage radiotherapy for PSA biochemical progression. Median age was 65. The trial was powered on freedom from distant metastases, designed to detect a rise from 90 percent with salvage to 95 percent at 10 years.

At a median 4.9 years, 649 of 697 men allocated adjuvant radiotherapy (93 percent) had it within 6 months, while only 228 of 699 (33 percent) in the observation group had radiotherapy within 8 years. That single number is the practical result: two men in three were spared pelvic radiotherapy.

With 169 events, 5-year biochemical progression-free survival was 85 percent with adjuvant and 88 percent with salvage radiotherapy, hazard ratio 1.10 (95 percent confidence interval 0.81 to 1.49, p=0.56). Freedom from non-protocol hormone therapy at 5 years was 93 against 92 percent, hazard ratio 0.88 (0.58 to 1.33, p=0.53).

The harm was measurable and one-sided. Self-reported urinary incontinence was worse at 1 year after adjuvant radiotherapy (mean score 4.8 against 4.0, p=0.0023), and grade 3 to 4 urethral stricture within 2 years occurred in 6 percent against 4 percent (p=0.020). The conclusion, that an observation policy with salvage radiotherapy should be the standard, is now written into practice.