Introduction Fire-fighting occupations and nightshift work are possibly/probably carcinogenic to humans (Groups 2A/2B), according to IARC. Some recent studies also found a higher risk for prostate cancer (PCa) for these occupational categories. However, results are inconsistent and most did not consider the aggressiveness of the tumour.

Objectives To study the risk of PCa among protective service workers and medical professionals, occupations frequently entailing night-shift work, with a particular interest for aggressive cancers.

Methods EPICAP, PROtEuS and MCC-SPAIN are three population-based case-control studies conducted respectively in France, Canada and Spain that included overall 3,859 PCa cases newly diagnosed between 2005 and 2014 in men ≤ 85 years old and 4,359 population-based controls frequency-matched on age. Participants have been interviewed face-to-face on their socio-demographic characteristics, lifestyle, leisure activities and complete occupational history for each job held. Occupations were coded using the International Standard Classification of Occupations 1988. Unconditional logistic regressions were performed to assess the association between selected occupations and PCa risk, using the Gleason score at diagnosis, after adjusting for potential confounders.

Results Regarding protective service occupations, we observed positive associations with PCa among participants who has ever worked as police officers (odds ratio (OR)=1.49 [95% confidence interval 1.03 ; 2.17]), as police inspectors and detectives (OR=1.90 [1.06 ; 3.40]), and as fire-fighters (OR=1.62 [0.92 ; 2.86]). We found a negative association for those who ever worked in the armed forces (OR=0.67 [0.53 ; 0.86]). Positive associations with PCa were observed for health professionals (except nursing) who had worked ≥10 years (OR=1.54 [0.99 ; 2.39]). Analyses taking into account PCa aggressiveness, screening and nightshift work are in progress.

Conclusion Excess PCa risks were observed for occupations that involve a high frequency of nightshift work.