Introduction
Among common types of non-Hodgkin’s lymphoma, diffuse large B-cell
lymphoma (DLBCL) accounts for approximately 35% of lymphoma cases in
western countries (1-3). Most often, chemoimmunotherapy with standard
regimens such as R-CHOP (rituximab, cyclophosphamide, doxorubicin,
vincristine prednisone) is the treatment for DLBCL patients. However,
prognosis of these patients is highly heterogeneous and it is very
difficult to predict the final outcome of the disease in the patients.
In addition, about 40% of DLBCL patients experience relapse or are
resistant to treatment (4, 5).
In the recent years, several prognostic factors such as Hemoglobin,
Lymphocyte/Monocyte Ratio, Beta-2 microglobulin, and
Neutrophil/Lymphocyte Ratio have been proposed to project the survival
rate of DLBCL patients (6-9). Nevertheless, easier and more available
factors with high sensitivity are required for prediction of prognosis
of DLBCL patients. Red blood cell distribution width (RDW) is considered
a systemic inflammatory response marker that can be easily evaluated
through the Complete Blood Count (CBC) test and has acceptable
sensitivity in many diseases such as cardiovascular and autoimmune
diseases and sepsis (10-13). D-Dimer as a sensitive index of the process
of fibrin formation and destruction is widely used in the deep venous
thrombosis detection, intravascular coagulation, sickle cell anemia, and
myocardial infarction (14-18). Recent studies introduced that
tumor-related degradation products for the coagulation and fibrinolytic
system, such as D-Dimer, can be used as outcomes prediction for tumor
(19). Furthermore, scientific evidence recently revealed the association
of RDW and D-Dimer with many cancers such as breast cancer (20-22), lung
cancer (23, 24), blood cancers (25-27), prostate cancer (28), and other
malignancies (29-32). However, the prognostic roles of RDW and D-Dimer
in cancer and its possible mechanism in tumor progression are being
discussed. Besides, several studies indicated that D-Dimer had a
possible role in proliferation of cancer cells, adhesion, and
angiogenesis, which may bring about malignant tumors growth. Cancer
patients usually face hypercoagulable states that increase the risk of
embolism. Hence, D-Dimer levels have prognostic role and are associated
with survival of patients with cancer. Considering the differences
between the results of the studies regarding sample sizes, study
designs, and the controversy among the results, we deemed it necessary
to conduct a meta-analysis regarding comprehensively investigating the
RDW and D-Dimer prognostic roles among patients with DLBCL.