Mantle Cell Lymphoma in Brazil: First Report from a Real-World Evidence Study of a Third World Country

Introduction: Mantle cell lymphoma (MCL) is an uncommon type of B-cell lymphoma with an heterogeneous clinical presentation and evolution spanning from an indolent leukemic non-nodal disease to an aggressive blastoid or pleomorphic nodal disease. Moreover, MCL has strong prognostic factors such as MIPI, proliferating index by ki-67 and, recently, P53 mutation. The best therapy seems to be an intensive one with rituximab-cytarabine based induction followed by an autologous stem-cell Transplantation with median overal survival (mOS) exceding 10 years. Real world evidence studies (RWE) are important to compare clinical outcomes and population characteristics with the ones from clinical findings. Moreover, the majority of MCL patients are treated in the public system in Brazil without access to important terapies such as rituximab and BTKinhibitors.

Objective: We aimed to describe epidemiological characteristics, type of therapy and clinical outcomes of Brazilian patients with MCL diagnosticated between Jan 2010 until Dec 2021. Moreover, the comparison between outcomes according to the place of treatment (public vs private) were analyzed as well. This first report include patients from 5 public and 1 private centers from 3 cities: Rio de Janeiro, Petropolis and Brasilia.

Patients and Methods: This RWE study began locally in Rio de Janeiro but is currently being expanded across all Brazilian institutions that fulfilled the compliance and confidentiality forms. Only patients with Cyclin D1 and/or SOX11 positivity are included. All the data is collected locally and typed in an eCRF (Redcap by Einstein Hospital). This analysis were made with patients from 5 included institutions. Ki-67 values were retrieved from the pathological reports as percentages of positive MCL cells. A sample of patients from one public center was tested for P53 by immunohistochemistry(IHC) and results were scored as percentage of positive MCL cells. Statistical tests were done with SPSS 20.0 software. Survival curves were made by the Kaplan-Meier Method and compared with Log Rank test.

Results: The study included 75 patients (56 males and 19 females). Median age at diagnosis was 64 years (24y-96y). The ECOG was 0 or 1 in 68 patients. Lymphocytosis was present in 22 patients. MIPI risk-groups could be obtained in 63 patients and it was low in 18, intermediate in 23 and high in 22. The ki-67 was obtained in 43 patients and was ≤ 30% in 28, between 31% and 49% in 11 and ≥ 50% in 12 patients.The citology was reported for 24 patients and it was blastoid or pleomorphic in 8. Fifty-seven patients were treated in public institutions and 26 patients received intensive therapy among 56 patients with less than 70 years at diagnosis. The mOS was 2.1 years (0.3-8.5) for the living patients. Thirty-one patients were alive at the last follow up. The analysis of mOS according to the MIPI was 2.5y for low, 2.7y for intermediary and 2.2y for high-score (P=0.98). The Ki-67 (%) had an adverse prognosis at a cut off of 50% positive cells (3.2y vs 1.6y, P =0.01). Patients with less than 70y had different mOS according to the type of treatment given(mOS for intensive therapy 3.3y vs 1.8y (p=0.04) and there was no difference in mOS between patients treated at public vs private institutions (P=0.34). We did p53 by IHC in 19 patients and there was a trend towards worse mOS for those with > 10% positivice cells (P=0.08).

Discussion: We showed the first report from a MLC study collecting RWE from a population of a third world country with low participation in MCL pivotal trials. To the best of our knowledge this is the first attempt to describe epidemiological data and OS for MCL in a multicenter setting. The main finding is that the patients had much worse overall survival than the ones reported in studies from developed countries. Unfortunately, morphology (blastoid/pleomorphic vs others) were not reported in a majority of patients and we should work on that. Our patients had a higher percentage of adverse prognostic factors such as a high MIPI and elevated KI-67. However, the previous was not prognostic and the latter was at a cut off of 50%. P53 seems to be of prognostic importance however our sample was still short. We are looking at more detail on the factors that could explain this poor OS such as the time to diagnosis/therapy and the availability of adequate therapy.

Xavier:Takeda: Other: Speaker, Advisory board, commented articles and scientific event; Janssen: Other: Speaker, Advisory board, PI in clinical trial and scientific event ; Amgen: Other: Speaker.