The recent report by Chen et al. (2011) also supports the lifetime carcinogen hypothesis. If we presume that the only effect of alcohol drinking was to increase the growth rate of pre-existing tumors, then the relationship between breast cancer risk and alcohol drinking would be limited to recent drinking. However, Chen et al found that when examined separately, alcohol consumption in early adulthood (18 to 40 years) and after 40 years, were both strongly associated with the risk of breast cancer (Chen et al., 2011). These findings are not consistent with a pure tumor-promoter type mechanism for ethanol and breast cancer, but are consistent with a cumulative carcinogen mechanism.
