- Design
- Population-based cohort study using linked registry and national death data, indirect standardisation
- Population
- 21,503 first kidney transplant recipients in Australia and New Zealand, 1990-2019, 212,317 person-years
- Primary outcome
- Skin cancer mortality rate and standardised mortality ratio versus the general population
- Effect
- 118.2 deaths per 100,000 person-years (95% CI 104.1-134.2); SMR 11.1 overall, 4.5 for melanoma, 34.5 for keratinocyte cancer
That transplant recipients get more skin cancer is established. What this study quantifies is how much of it kills them, and which cancer does the killing.
The Australia and New Zealand Dialysis and Transplant Registry was linked to national death registers for 21,503 people who received a first kidney transplant between 1990 and 2019, giving 212,317 person-years of follow-up. There were 251 skin cancer deaths — 82 from melanoma, 169 from keratinocyte cancer. Absolute skin cancer mortality was 118.2 per 100,000 person-years (95% CI 104.1-134.2).
Against the general population, the standardised mortality ratio was 11.1 overall. Split by type it is 4.5 for melanoma and 34.5 for keratinocyte cancer. That asymmetry is the finding. Surveillance in transplant recipients has inherited melanoma-shaped thinking — look for the changing pigmented lesion — while the cancer producing most of the excess deaths is the keratotic one that gets watched.
Excess mortality was present in both sexes, every age group, every region and every decade, and was highest where ultraviolet exposure is highest: Queensland (SMR 14.8, 95% CI 11.7-18.8), Western Australia (13.1, 8.7-19.7) and New Zealand (11.0, 8.3-14.6). Much of India sits in a comparable ultraviolet band, and no equivalent Indian registry linkage exists — which is a reason to apply the surveillance principle here, not to assume the rate transfers.
- Treat a new keratotic lesion in a transplant recipient as needing definitive treatment, not observation
- Set a surveillance interval at transplant and record it in the discharge letter
- Do not let melanoma-focused teaching set the surveillance priority in this group
- Ultraviolet exposure modified the risk sharply — factor in occupation and geography
- Rapid treatment entry matters as much as detection; a waiting list undoes the surveillance
Why it matters
The cancer causing most skin cancer deaths in transplant recipients is the one surveillance treats as low-priority.
Don't overread it
This is registry data from two high-ultraviolet countries; the absolute rates should not be transferred to a different population.
The statistics, in plain English
A standardised mortality ratio of 34.5 means deaths from keratinocyte cancer occurred about 34 times more often than expected for people of the same age and sex in the general population. That sounds vast, and it is, but the baseline is very low — the absolute rate was 79.6 per 100,000 person-years. Both numbers matter: the ratio tells you where the excess is, the absolute rate tells you how much surveillance capacity it justifies.
Read the rest in the app
You have read your two free briefings this month. The app carries all 27 specialties, every morning, free — and this finding is waiting in it.
Scan to keep reading on your phone. No account needed to start.
Tomorrow morning, before your first patient
One edition a day for dermatology, written by the desk, every claim tied to its paper. Six minutes.
Get the app — free