Occupational exposure to metals and prostate cancer: CAPLIFE study

Few studies have explored the association between occupational metal exposure and prostate cancer (PCa), without considering combined effects and tumor characteristics. The aim is to analyze the potential individual and joint exposure to occupational metals on PCa risk, considering tumor aggressiveness and stage. CAPLIFE is a case-control study that included 464 cases and 428 controls. Lifetime occupational exposure to chromium (Cr), nickel (Ni), iron (Fe), and lead (Pb) was estimated using the Spanish job-exposure matrix (MatEmESp). Metal exposure was defined as: i) ever vs. never exposure; ii) lifetime cumulative exposure (prevalence*intensity*duration); and iii) duration (years), both categorized into tertiles (T) based on controls. Multivariable logistic regression and Quantile g-Computation models assessed individual and joint effects, stratified by International Society of Urological Pathology (ISUP) grade and tumor stage [localized and locally advanced (cT3/cT4 or N1) or metastatic (M1) tumors]. No association was observed between individual metal exposure and overall PCa, nor when stratified by ISUP grade. For locally advanced or metastatic tumors, higher odds were observed for Cr, Ni, and Fe. Specifically, the strongest associations were observed for Ni [exposure, aOR_evervsnever= 1.99 (95%CI 1.02-3.89), lifetime cumulative exposure, aOR_T3vsnever= 3.53 (95%CI 1.34-9.30), and duration, aOR _T3vsnever= 3.58 (95%CI 1.37-9.37)]. Metal mixture exposure was also associated with locally advanced or metastatic tumors, aOR= 1.41 (95%CI 1.04-1.91), with Ni showing the only positive weight. In conclusion, no association was found for overall PCa, nor with the ISUP grade. However, exposure to Cr, Ni, and Fe, as well as joint metal exposure, was linked to higher odds of locally advanced or metastatic PCa. Although these results should be interpreted with caution as occupational exposure was estimated using a job-exposure matrix, they may, if confirmed, support preventive strategies to reduce occupational metal exposure.