In adults, acute lymphoblastic leukemia (ALL) is a rare cancer, even among hematologic malignancies, and is generally associated with long-term survival rates of approximately 40%. Conversely, ALL is the most common cancer in children and, with steady advances fueled by systematic randomized clinical trials over the decades, is now curable in more than 80% of cases.
One of the most important reasons for the worse outcomes among adult patients with ALL is intrinsic disease biology. Poor-risk genetic features occur with higher frequency, and favorable-risk genetic features occur with lower frequency in adults compared with children. A striking example of this is Philadelphia chromosome–positive (Ph+) ALL, which occurs in 25% of adult patients with ALL but in fewer than 5% of childhood patients. Importantly, the addition of BCR-ABL tyrosine kinase inhibitors (TKIs) to chemotherapy for Ph+ ALL appears to markedly improve responses. Notwithstanding these clear differences in disease biology in adults compared with children, evidence is emerging that adopting a pediatric-inspired treatment approach for adolescents and younger adults (AYAs) with ALL results in improved survival.
The impetus for developing the first NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for ALL (in this issue) arose from our desire for every adult diagnosed with ALL in 2012 and beyond to reap the benefits of 2 major recent advances that have redefined “standard of care” for adult ALL: 1) recognition that pediatric-inspired treatment regimens are both feasible and associated with improved survival in younger adult patients compared with traditional “older adult” regimens, and 2) recognition that including TKIs in the treatment of Ph+ ALL is associated with improved response and survival.