Discussion
The prognostic roles of RDW and D-Dimer were explored in subjects with
DLBCL. We observed that high RDW and D-Dimer were two prognostic factors
related to OS and PFS among DLBCL cases. Recently, evidence has been
confirmed the relationship between RDW and poor prognosis in various
cancers (44, 45). Furthermore, increased RDW was associated with worse
prognosis in blood malignancies such as chronic myeloid leukemia (46),
chronic lymphocytic leukemia (47), NK/T lymphoma (48), multiple myeloma
(49), and DLBCL (40).
Inflammation is a pivotal factor which plays a role in progression of
tumor and is known as one of its prominent features (25, 50). In this
study, the pooled analysis results revealed that high values of RDW were
associated with poor PFS and OS. Although the main mechanism of the
relationship between RDW and the prognosis of DLBCL patients has not
been clearly and fully investigated, high RDW can be attributed to the
disturbance in erythropoiesis and the changes in red blood cell
maturation (51).
Some findings have provided evidence that there is an association
between RDW and some markers such as IL-6, CRP (C - reactive protein),
TNF-I and II (Tumor Necrosis Factor), TK (Thymidine Kinase), ESR
(Erythrocyte Sedimentation Rate), and Ferritin which the accuracy and
sensitivity in DLBCL patients are in a state of ambiguity (13). The
relationship between RDW and malnutrition conditions might be explained
by treatment with poor response and poor prognosis of patients who
suffer from cancer (41). In addition, the disruption in iron absorption
and metabolism mechanism observed in most cancers also contributes to
increase the level of RDW (52), and increased RDW is considered as a
turning point in the relationship between inflammation and worse
prognosis of subjects who suffer from DLBCL. On the other hand, poor
coagulation conditions are associated with poor prognosis and the
outcomes such as VTE (venous thrombosis embolism) and DIC (disseminated
intravascular coagulation).
Treatment of various cancers is associated with hypercoagulable states
and according to the evidence, the changes in coagulation and
fibrinolysis pathways have a great impact on cancer prognosis
(19).Moreover, tumor-related degradation products such as D-Dimer as a
prognostic factor of the final outcome should be used in all types of
cancer (20, 26, 29). Some studies have indicated that elevated D-Dimer
values as a suitable factor in solid tumor patients is associated with
poor prognosis (53) and D-Dimer decreases significantly after the first
chemotherapy (19). Also, it has been proved that there is an association
between values of D-Dimer and tumor progression, distant metastasis, and
tumor volume (54, 55). However, our pooled analysis results showed that
by increasing in the D-Dimer values as a prognostic factor, we witnessed
worsening OS in the DLBCL patients.
In this study, our findings determined the prognostic role of RDW and
D-Dimer in DLBCL patients. Since the values of RDW and D-Dimer can be
easily accessible in the patient tests at low cost, considering to these
prognostic indicators would be helpful in the prognosis of DLBCL
patients. However, the present study had some limitations. As a result
of small number of publications on the role of D-Dimer in DLBCL
patients, it was not possible to provide PFS in this study. On the other
hand, the basic values for grouping the individuals based on RDW were
different in the studies. Therefore, we could not be able to conduct
subgroup analysis.