Timely disclosure of progress in childhood cancer survival by 'period' analysis in the Automated Childhood Cancer Information System.

BACKGROUND A few years ago, a new method of survival analysis, denoted 'period' analysis, was introduced to provide more up-to-date survival estimates of cancer patients. PATIENTS AND METHODS We evaluated the period survival method using the large database of the Automated Childhood Cancer Information System (ACCIS). Our evaluation is based on data from 35 191 children diagnosed with cancer in 13 European countries between 1975 and 1989 and followed for vital status until around 1999. RESULTS Using the follow-up data available in 1989, 10-year survival for all children with cancer calculated by the period method for the 1985-89 period was 58%, while it was 43% when calculated by traditional 'cohort' life-table analysis (based on children diagnosed in 1975-79). The period method provided a better estimate of the true 10-year survival of 62%, observed 10 years later in the cohort of patients diagnosed in 1985-89. Similar results were observed for each of the common groups of childhood cancer. CONCLUSION Period analysis is especially useful for monitoring childhood cancer survival, because at a given point in time it provides more timely estimates of long-term survival expectations than the cohort life-table method. Using the ACCIS database, up-to-date estimates of period survival for childhood cancer are derived in subsequent papers in this journal.