Care needed in interpretation of cancer survival measures.

[First paragraph] Cancer patient survival obtained from population-based cancer studies is the optimum method to monitor and assess the effectiveness of patient care.1 Consideration of these estimates in conjunction with estimates of cancer incidence and mortality is still important.2 As a result, there is much interest in the assessment of progress in terms of cancer survival.3 and 4 Quantification of the improvements in cancer patient survival because of successes in some areas, such as treatment, diagnostic techniques, and awareness or screening campaigns, is of paramount importance to health-care officials, health policy makers, and charities supporting these developments in cancer control. However, to make a fair comparison—to compare like with like—is essential to assess progress accurately.