The primary goal of screening for breast cancer is to detect the disease at a smaller size and presumably earlier stage. A review of the literature is presented, which evaluates the ability of thermography, mammography, and clinical examination to lower the threshold size at detection and evaluate the predictive value of a positive test as compared with the prevalence of cancer existing in the population reported. We have found little evidence to indicate that clinical thermography lowers the stage at detection, and neither does a positive thermogram in screening seem to have a strong predictive value. Clinical examination can lower threshold over current threshold levels, but only at the expense of a very high biopsy rate. The data reported in the literature show that mammography can advance the stage at detection and have a reasonably high predictive value compared with the isoprobability baseline.