Osteonecrosis: a treatment related toxicity in childhood acute lymphoblastic leukemia (ALL)--experiences from trial ALL-BFM 95.

BACKGROUND: Osteonecrosis (ON) as a complication during treatment of acute lymphoblastic leukemia (ALL) has gained rising attention over the past decade. Corticosteroids, representing an essential element of antileukemic therapy, are known to induce ON, which in turn may cause significant morbidity. Due to spontaneous reporting of affected patients with ON, a group-wide evaluation was performed to determine incidence, risk factors, and morbidity for ON.

PROCEDURE: Patients were identified via spontaneous reporting to the study center and via questionnaire, addressing all 64 participating centers. We retrospectively analyzed 1,951 patients below 18 years of age who were treated according to trial ALL-BFM 95 between 01.01.1996 and 30.06.2000.

RESULTS: Thirty-one patients (14 male, 17 female) affected by ON were identified. The overall 5-year cumulative incidence for ON is 1.8%. The incidence for patients <10 years is 0.2%, whereas for patients >/=10 years it is 8.9% (P = 0.00) and 16.7% (P = 0.003) for patients >/=15 years. The majority (n = 20) showed ON in two or more joints, and the joints most commonly affected were knees (14 patients, 24 affected knees) and hips (11 patients, 20 affected joints). Thirteen out of 31 patients had to undergo surgery in the course of their disease.

CONCLUSIONS: Symptomatic ON is a rare event in patients treated with BFM-type chemotherapy with an overall 5-year cumulative incidence of 1.8%. The age group >/=10 years, and particularly adolescents >/=15 years have a significantly higher risk of developing ON.