Objective To assess the risk of skin cancer in persons treated with neonatal phototherapy (NNPT) for jaundice.

Design Retrospective cohort study.

Setting Grampian Region, Scotland, UK.

Data source Aberdeen Maternity and Neonatal Databank. NNPT exposure was abstracted from paper records spanning 1976–1990. Follow-up to 31 December 2006 by linkage to cancer registration and mortality records.

Main outcome measures Incidence ratios, standardised for age, sex, calendar period and socio-economic position.

Results After excluding neonatal deaths (n=435), the cohort comprised 77 518 persons. 5868 Received NNPT, providing 138 000 person-years at risk (median follow-up, 24 years). Two cases of melanoma occurred in persons exposed to NNPT versus 16 cases in unexposed persons, yielding a standardised incidence ratio of 1.40 (95% CI, 0.17 to 5.04; p=0.834). No cases of squamous cell or basal cell carcinoma of skin were observed in exposed persons.

Conclusions Although there is no statistically significant evidence of an excess risk of skin cancer following NNPT, limited statistical power and follow-up duration mean it is not possible categorically to rule out an effect. However, taken in conjunction with the results of the only other study to investigate risk of melanoma following NNPT, evidence available so far does not suggest a major cause for concern.