Cancers, Mainly Male, as Population Biomarkers for Breast Cancer Mortality

Background. BCM correlates significantly with mor tality from other site-specific cancers and cardiovascular diseases for both sexes. These other mortalities could be used as independent biomarkers (predictors) of BCM allowing an evaluation of the importance of common etiological factors. Methods. BCM (age-adjusted, 45–74 years), obtained around 1992 from 37 countries worldwide, was estimated in multivariate regression to identify the best predictors. Results. Male and female biomarkers predicted BCM with a R2 of 0.80 and 0.69, respectively. Strongest correlation was obtained with male colon, prostate, lung, and rectum cancer and female esophagus cancer (R2 = 0.84, P < 0.0001). The estimated independent mean percentage contribution ± SD to BCM was 40 ± 7 from prostate cancer, 38 ± 9 from male colon, 13 ± 6 from male lung and rectum cancer combined, and 9 ± 3 from female esophagus cancer. The regression equation (1992 data) predicted mean BCM in 28 available countries from 1967 to 1991 with a mean error of 5%. BCM in individual countries was also reliably predicted from 1967 to 1991, r = 0.86 to 0.90 (P < 0.0001). In 1953, r was 0.74 (P < 0.0001). Conclusions. The evidence suggests a major influence of modifiable environmental factors common to BCM, its biomarkers, and both sexes: most likely nutrition, smoking, and alcohol intake. The results obtained with male data suggest a minor impact of sex-linked risk factors and, until recently, of treatment and early detection on BCM at the population level.