Survival following relapse in childhood haematological malignancies diagnosed in 1974-2003 in Yorkshire, UK.

We examined population-based information on relapsed childhood haematological cancers, investigating factors that might influence both overall survival and survival following relapse among the 1177 children (0-14 years) diagnosed with a haematological malignancy in Yorkshire from 1974 to 2003, of whom 342 (29%) relapsed at least once. Leukaemia patients from more deprived areas were significantly less likely to relapse (odds ratio=0.54, 95% confidence interval 0.32-0.93 for most deprived quintile vs least deprived quintile; P(trend)=0.06), especially those with acute myeloid leukaemia (P=0.04). Neither ethnic group nor distance to the main treatment centre was associated with risk of relapse. Overall, patients who relapsed at least once had 5-year survival rates of 46% (41-51%) compared with 79% (76-81%) of those who did not. Five-year survival rates from the time of first relapse increased from 20% in 1974-1983 to 45% in 1984-2003. Length of first remission was a strong predictor of survival for leukaemia with a 46% reduced risk of death for every additional year of event-free survival. Of children who experienced a relapse, 46% survived at least 5 years, whereas just under half of patients survived 5 years beyond disease recurrence. This provides a baseline for future comparisons and demonstrates that relapsed childhood cancer need not imply a poor outcome.