ALK-positive ALCL responds well to standard chemotherapy treatments, putting most patients in long-term remission. Most people with ALK-negative ALCL initially respond to treatment, but more people will relapse within five years than those with ALK-positive ALCL. ALK-negative patients (and some ALK-positive patients with certain risk factors) are sometimes treated more aggressively, often with a stem cell transplantation after remission. ALK-positive ALCL usually affects children and young adults. ALK-negative ALCL is more common in patients over the age of 55 years.