Cancer screening promises health benefits but it also delivers harms and costs. A substantial problem is overdiagnosis of tumors not needing treatment. There are well established principles for starting cancer screening, but we also need periodical evaluations and stopping rules. For that we must have the results of methodic empirical studies with proper estimates of benefits and harms. Proponents of screening emphasize its advantages but hold back on its drawbacks. Several studies have argued that a universal population screening approach, especially for breast cancer, is no longer tenable. We need a fresh and independent assessment of screening practices.