Last Updated: 2009-11-03 17:39:08 -0400 (Reuters Health)

NEW YORK (Reuters Health) - A retrospective study of children with acute lymphoblastic leukemia (ALL) suggests that the remission rate after first relapse may be higher than previously reported.

In an October 19th on-line publication in the Journal of Clinical Oncology, Dr. Mignon L. Loh of UCSF Children's Hospital, San Francisco, and colleagues observe that as members of The Therapeutic Advances in Childhood Leukemia (TACL) Consortium, they sought to gain more information on treatment efficacy.

In particular, their aim was to define response rates and disease-free survival rates in the 20% or so of ALL patients with relapsed or refractory disease. These findings would establish a comparator for future studies, including those assessing the efficacy of novel treatment approaches.

The team gathered data on patients with relapsed and refractory ALL treated at TACL institutions between 1995 and 2004 and compared outcomes with those in published reports.

Ultimately they analyzed findings in 225 patients who had at least one treatment for medullary relapse or for induction failure.

The complete remission rate for early first relapse (less than 36 months from diagnosis) was 83%. In contrast, the authors note, other researchers have reported remission rates of roughly 70% after a first early relapse.

Complete remission rates were 93% for first late marrow relapse, 44% for the second and 27% for the third.

Rates of 5-year disease-free survival were 27% after the second complete remission and 15% after the third. These results, say the investigators, "are similar to those found in the literature, though exact comparisons are difficult as a result of different cohorts of patients analyzed with different end points."

Nevertheless, having established these baseline rates, the investigators conclude that further analysis of their data "may yield valuable information regarding different chemotherapeutic regimens used and may identify particular regimens that have been more successful than others."

J Clin Oncol 2009.