Diagnosis and Staging:
The diagnosis of B-LBL was confirmed by expert haematopathologists on biopsy specimens based on the standard morphologic and immunophenotypic criteria. Staging workup included Whole-body PET/CT or Contrast-enhanced computerized tomography (CT) scans of thorax, abdomen, and pelvis, bilateral bone marrow aspiration/biopsy and cerebrospinal fluid analysis. Baseline marrow flowcytometric minimal disseminated disease (MDD) assessment by 8 to 10 color acute leukemia panel (>5lakh events) was done and analyzed using Kaluza version 1.3™. Modified St. Jude classification was used for staging.
Treatment :
All patients were treated uniformly on a modified BFM-90 protocol8. Figure-1 depicts the treatment schema used in the study. Following a 7-day prednisolone pre-phase, phase I 4-drug “induction” was delivered over 4-weeks, followed by phase II “induction” over 4-weeks; phase M contained 4-cycles of high-dose methotrexate administered as a 24 hrs continuous infusion; Re-intensification phase containing a truncated re-induction and consolidation over 6-weeks, was administered to all pB-LBL patients with advanced-stage disease (Stage III and IV). Also, a decision to give re-intensification phase in limited-stage disease (Stage-I/II) with baseline detectable MDD and/or PET positivity in the marrow and to administer local irradiation for persisting residual disease post-induction phase II irrespective of the stage was taken in Multidisciplinary tumor boards discussions on a case-by-case basis. Both limited and advanced-stage B-LBL patients were given oral maintenance chemotherapy for a period of 2years. Central Nervous System chemoprophylaxis included high dose methotrexate and intrathecal methotrexate. Until 2013, prophylactic cranial irradiation (12.6 Gy) was administered for CNS-1 & 2 status, and this was discontinued thereafter, while CNS-3 patients, continued to receive therapeutic cranial irradiation (18 Gy) after re-intensification phase. Patients with testicular involvement at presentation and having residual disease persisting post-induction phase II (D64) received testicular irradiation (24 Gy) .