Relapse rate after cessation of therapy in childhood leukemia. A material from the five Nordic countries

The experience of four hundred and ninety children from the Nordic countries who had their antileukemic therapy stopped prior to January 1981 is presented. The observation times after stopping therapy were between 1 month and 19 years. One hundred and five children (21.4%) relapsed before January 1981. No children relapsed later than four years after cessation of therapy. The calculated long term relapse rate is 28%.