HOW TO TREAT B-CELL LYMPHOMA, UNCLASSIFIABLE, WITH FEATURES INTERMEDIATE BETWEEN DIFFUSE LARGE B-CELL LYMPHOMA AND BURKITT LYMPHOMA. SINGLE CENTRE EXPERIENCE.

ABSSUB-3784

Background: B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma (DLBCL/BL) is a separate entity in the WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues 2008. It is nowadays a provisional category of a spectrum of features between two borderline lymphomas – difusse large B-cell lymphoma (DLBCL) and Burkitt lymphoma (BL). These lymphomas have morphological and genetic features of both DLBCL and BL, so they cannot be clearly  included in either one of those two entities. DLBCL/BL generally has an agressive clinical course and no guidelines for treatment are available yet.

Aims: To compare efficacy of different treatment options.

Methods: Retrospectively we reviewed clinical data from our institution's register between years 2010-2013. Subsequently we analysed therapy outcome due to chosen regimens. The treatment strategy decision was made depending on patient's age, clinical stage of the disease and the IPI score. All of the histology samples were reviewed by experienced pathologists, in majority of the cases including FISH and genetic abnormalities diagnostic tests.

Results: Since January 2010 to December 2013 we registered 30 patients with newly diagnosed DLBCL/BL, constituting approximately 3.4 % of all non-Hodgkin lymphomas (n=881). For comparison, in the same time period, we registered 301 cases of DLBCL (34%) and 16 cases of BL (1.8%). There were 14 men and 16 women, average age being 65 years (38-86y). One patient (86y) was treated by paliative radiotherapy only and died within 1 month due to lymphoma progression. 10/30 patients (33%), average age 53y (38-66y), clinical stage I-IV, average IPI score 3 (0-5), median LDH 5.27 µkat/l (2.79-107), were treated with intensive approach, when R-CHOP treatment was enhanced with 3-4 cycles R-CODOX-M with or without R-IVAC up to 5-7 chemotherapy cycles total. Two patients  from this group died, one (53y) had confirmed concurrent BCL2-IGH and MYC rearrangement (double-hit lymphoma), was primarily chemoresistant, and died within 4 months from diagnosis due to lymphoma progression. The second one (60y) died due to treatment toxicity and concurrent illness (sepsis and ischemic cerebral stroke) immediately after treatment completion. The remaining  8 patients (80%) from a group of intensively treated are nowadays in complete remission lasting 3-31 months depending on the treatment completion date. 19/30 patients (63%), average age 71y (57-86y), clinical stage I-IV, average IPI score 3 (0-5), median LDH 4.99 µkat/l (2.5-40.14), got usual R-CHOP based chemotherapy, in 9 cases (47%) including 1-2 cycles of high dose methotrexate or high dose cytarabine finally. 3 patients (16%) from this group died during the treatment or within 6 months after treatment completion due to lymphoma progression. 3 patients (16%) from this group relapsed within one year and recieved another chemotherapy regimens. 13 patients (68%) from this group are in complete remission or the treatment is nowadays still ongoing. We haven't  evaluated the disease free survival (DFS) and overall survival (OS) yet, because of short follow-up.

Summary/Conclusion: Despite short follow-up, our data suggest that R-CHOP based chemotherapy is less effective than it's combination with intensive regimens containing R-CODOX-M and R-IVAC. The most important factor that influenced the treatment strategy was patients' age. For setting the proper treatment guidelines bigger patients cohorts and a longer follow up of the survivals are required.

Keywords: None

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