Achieving a complete cytogenetic response (CCgR) is a major target in the t
reatment of chronic myeloid leukemia (CIVIL) with interferon-alpha (IFN-alp
ha), but CCgRs are rare. The mean CCgR rate is 13%, in a range of 5% to 33%
. A collaborative study of 9 European Union countries has led to the collec
tion of data on 317 patients who were first seen between 1983 and 1997 and
achieved CCgRs with IFN-alpha alone or in combination with hydroxyurea. The
median time to first CCgR was 19 months (95% Cl, 17-21; range, 3-84 months
). At last contact, 212 patients were still alive and in continuous CCgR; 1
05 patients had lost CCgR, but 53% of them were still alive and in chronic
phase. IFN-alpha treatment was discontinued permanently in 23 cases for res
ponse loss, in 36 cases for chronic toxicity (15 are still in unmaintained
continuous CCgR), and in 8 cases because it was believed that treatment was
no longer necessary (7 of these 8 patients are still in unmaintained conti
nuous CCgR). The 10-year survival rate from first CCgR is 72% (95% Cl, 62%-
82%) and is related to the risk profile. High-risk patients lost CCgR more
frequently and more rapidly and none survived more than 10 years. Low-risk
patients survived much longer (10-year survival probability 89% for Sokal l
ow risk and 81% for Euro low risk). These data point out that a substantial
long-term survival in CCgRs is restricted mainly to low-risk and possibly
intermediate-risk patients and occurs significantly less often in high-risk
patients. (C) 2001 by The American Society of Hematology.