In a trial that equalised access, outcomes did not follow disadvantage

Design

analysis of demographic and metabolic factors within a randomised controlled trial of imaging-guided salvage radiotherapy

Population

157 post-prostatectomy men with detectable PSA completing per-protocol salvage radiotherapy, followed to 48 months

Primary outcome

failure-free survival by race, socioeconomic status and allostatic load

Effect

72.8% (95% CI 53.8 to 85.0) vs 58.7% (46.6 to 68.9), P = 0.002 across both arms

A randomised trial assigned post-prostatectomy men with detectable PSA to salvage radiotherapy guided either by conventional imaging or by 18F-fluciclovine PET/CT, following them up to 48 months for failure-free survival. This analysis asked how race, socioeconomic status and metabolic dysregulation - quantified as an allostatic load score - related to outcome: 81 men completed per-protocol treatment in the conventional arm and 76 in the PET arm.

African American men had higher failure-free survival than men of other races across both arms, 72.8% (95% CI 53.8 to 85.0) against 58.7% (46.6 to 68.9), P = 0.002. In the conventional imaging arm the difference was 64.0% against 45.3% (P = 0.008); in the PET arm both groups did better and the difference narrowed to 81.5% against 73.0% (P = 0.131). Socioeconomic scores were lower and allostatic load scores higher in the African American men in both arms.

The finding matters because of what it implies about the usual explanation. Worse prostate cancer outcomes in Black men are frequently attributed to more aggressive tumour biology; here, inside a trial that standardised imaging, treatment and follow-up, the group with lower socioeconomic status and more metabolic dysregulation did better. That points at access and treatment delivery rather than biology as the driver of the disparity seen in routine care. The numbers are small and the subgroups were not what the trial was powered for, so this is a reason to interrogate pathways rather than a settled conclusion.

• Do not attribute worse outcomes in disadvantaged groups to tumour biology without evidence
• Audit time from PSA rise to salvage radiotherapy across your own patient groups
• Standardise imaging and treatment pathways rather than individualising by perceived risk
• Record and act on the treatable parts of allostatic load - blood pressure, glucose, lipids
• Read small subgroup analyses like this one as hypothesis-generating, in either direction

Why it matters

It undercuts the assumption that disparities in prostate cancer outcome are mostly biological, by showing them reverse when access is equalised.

Don't overread it

A post hoc subgroup analysis in about 157 men; it cannot establish why the difference occurred or that it generalises.

The statistics, in plain English

The confidence intervals are wide because the subgroups are small - 72.8% with an interval from 53.8% to 85.0% rests on 55 men in total. The P value of 0.002 comes from comparing two proportions that were not a prespecified trial comparison, so it does not carry the protection a primary endpoint would. In the PET arm the same comparison gave P = 0.131, which is the clearest sign that these estimates are unstable.

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