Retrospective study of relapsed ALL in a single institution in Brazil

Abstract

20018 Background: With contemporary protocols, 25–30% of children with ALL who achieve first complete remission (CR1) are expected to relapse. Although the majority of patients can achieve a second complete remission (CR2) with re-induction chemotherapy, only a few will maintain prolonged clinical remission. To study the pattern of ALL relapse in our institution, we performed a retrospective analysis of such events between 1994 and 2006. Methods: In the study period, 65 out of 292 (22%) patients treated at our institution for ALL suffered isolated or combined relapse. Median age was 7.2 years (range 0.4–18.2 years); 65% were male. Patients were analyzed according to immunophenotype, WBC, site of relapse and time to relapse. Kaplan-Meier life-table analyses were used to estimate survival; differences were assessed by the log-rank test. Results: Of 63 relapsed ALL that were immunophenotyped, 65% were B-cell precursors and 35% were T-cell. WBC was >50,000/mm3 in 47% of patients; 54% of them had isolated bone marrow (BM) relapse, 23% combined relapse and 23% isolated extramedullary (EM) relapse (11CNS and 4 testicular relapse); 58% had very early relapse (VER) (<18 months from CR1), 17% early relapse (ER) (18–30 months from CR1) and 25% late relapse (LR) (>30 months from CR1). The therapeutic approach was chemotherapy in 60 patients and BMT in five. CR2 was achieved in 63% of patients. Of these, 35% had a second relapse. Death rate was 66% with median follow-up of 5,3 months; 40% had cumulative survival rate = 4 years. Initial imunophenotype and WBC did not affect outcome. Patients with isolated EM relapse presented a significant superior outcome when compared with those with combined relapse (p=0.024). There was no difference in survival between isolated BM and combined relapse. As for the time to relapse, there was significant inferior outcome for patients with VER when compared with ER (p=0.0089) and LR (p=0.0041). However, there was no difference in survival between ER and LR group. Conclusions: In our casuistic, time to relapse was the main predictor of outcome. Despite continuous improvement in therapy of childhood ALL, survival rate of relapsed patients remains disappointing. No significant financial relationships to disclose.