Stem Cell Transplantation |
GvHD/Immunotherapy Committee of the Spanish Group of Hematopoietic Stem Cell Transplantation (GETH: Grupo Español de Trasplante Hemopoyético)
Correspondence: David Gallardo, MD, PhD, Clinical Haematology, Department, Institut Català dOncologia, Hospital Josep Trueta, Avda. França s/n, 17007 Girona, Spain. E-mail:27532dgg{at}comb.es
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Design and Methods: We performed a retrospective case-control study including 820 adult patients who had received an allogeneic stem cell transplant from an HLA-identical sibling donor. Quality of life (QoL) was assessed in 150 patients using the EORTC Quality of Life Questionnaire C30 (QLQ-C30).
Results: There were no statistically significant differences in overall survival at ten years (bone marrow: 48.9% vs. peripheral blood stem cells: 39.8%; p=0.621), transplant-related mortality (bone marrow: 28.9% vs. peripheral blood stem cells: 34.4%; p=0.682) or relapse incidence at 9 years (29.4% vs. 35.2%, respectively; p=0.688). Similar outcomes were maintained independently of the phase of the disease. However, multivariate analysis identified a higher incidence of acute graft-versus-host disease grades II-IV (p: 0.023; Hazard ratio [HR]: 1.41; 95% confidence interval [CI]: 1.05–1.89) and grades III-IV (p: 0.006; HR: 1.89; 95% CI: 1.20–2.98), in the peripheral blood stem cells-stem cell transplant group. As previously described, extensive chronic graft-versus-host disease was also more frequent in the peripheral blood stem cells group (28% vs. 15.6%; p<0.001). Patients transplanted with peripheral blood stem cells had significant impairment of role and social functioning.
Conclusions: Although overall survival was not affected by the stem cell source, peripheral blood stem cell transplants were associated with a higher risk of both acute and chronic GvHD. Global quality of life was similar in both groups, but patients transplanted with peripheral blood stem cells showed worse role and social functioning scores, probably related to the increased incidence of chronic graft-versus-host disease.
Key words: stem cell source, graft-versus-host disease, allogeneic stem cell transplantation.
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PBSC became the preferred source of stem cells for autologous transplantation between 1992 and 1996. However, for allogeneic transplantation the change of stem cell source was delayed three years, due basically to 2 major concerns. The first was the large number of T-lymphocytes infused with PBSC, which could lead to an increased development of acute graft-versus-host disease (aGvHD). The other concern was the long-term safety of the use of G-CSF in healthy donors. Nevertheless, the follow-up of these G-CSF mobilized donors up to six years showed the absence of long-term complications,2 leading to an increased confidence in the procedure. In addition, the first pilot studies and phase II trials demonstrated a faster hematologic recovery, as seen in the autologous setting, with no significant increase in aGvHD.3–5 All these factors led to an increase in the use of G-CSF mobilized PBSC for allogeneic SCT, and now, almost 75% of allogeneic SCT are performed with PBSC.1
However, many studies have shown that the use of PBSC was associated with an increased risk of chronic GvHD (cGvHD).6–8 Moreover, a randomized study performed by the EBMT showed an increased incidence of aGvHD after PBSC transplantation from HLA-identical sibling donors.8 The association between PBSC transplants and aGvHD has been later confirmed by two meta-analyses.9,10
Similarly, the impact of the stem cell source on transplant-related mortality (TRM) and overall survival (OS) in the allogeneic setting is still not clear. Whereas most of the studies have found a similar OS and TRM between BM and PBSC transplants,8,10,11 other authors found an association between the use of PBSC and a lower TRM and better OS.12–14 In contrast, Eapen et al.15 reported an increased TRM and a worse OS in children receiving an allogeneic PBSC transplant from an HLA-identical sibling, when compared with patients receiving allogeneic BM.
In order to detect the relevant differences between both stem cell sources, we conducted a retrospective case-control study to compare the clinical outcome of patients receiving PBSC or BM allogeneic transplantation from an HLA-identical sibling donor.
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Table 1. Comparison of the clinical characteristics between the bone marrow and the peripheral blood transplanted patients.
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2 test for qualitative variables and Students t-test for continuous variables.
The Kaplan-Meier method was applied for the analysis of OS and disease-free survival (DFS). Curves were compared using the log-rank test. Statistical incidence estimates were used to determine the cumulative incidence of aGVHD, non-relapse mortality and relapse depending on the stem cell source. Death without signs of aGVHD was considered a competing risk in the analysis of aGVHD incidence. Only aGVHD grades II–IV were considered for the analysis of aGVHD incidence. The competing risk for relapse was death in complete remission. Cumulative incidence of non-relapse mortality was calculated after considering death in complete remission as a competing risk. Multivariate Cox regression models using a backward stepwise procedure with the likelihood ratio criterion (inclusion/exclusion criteria: p
0.05/p>0.10, respectively) were applied to analyze the combined effects of stem cell source and other factors on OS, relapse, and aGVHD. All variables in the univariate analysis with a p value at or below 0.2 were included in the multivariate analysis. Univariate and multivariate logistic regression model were used to evaluate differences in chronic GvHD. p values were two-sided and those lower than 0.05 were considered statistically significant.
Grading of graft-versus-host disease and analysis of outcome
Acute GvHD was graded according to consensus criteria.16 Patients alive 80 days after transplantation with sustained donor engraftment were considered to be evaluable for chronic GvHD.
TRM was defined as death from all causes in the absence of relapse. Once patients were classified as in relapse, they remained so even if they entered a second remission after treatment. Disease-free survival (DFS) was calculated using the time interval from transplantation to either relapse or death in remission, whichever occurred first.
Quality of life assessment
QOL was assessed using the Spanish version of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire, EORTC QLQ-C30, version 3.0 17. The questionnaire consists of 30 items assessing five functional domains (physical, role, emotional, cognitive and social), symptom scales (fatigue, nausea and pain) and six single items (dyspnea, sleep disturbances, appetite loss, constipation, diarrhea, and financial impact of the disease and treatment) and a single global QOL scale. The response options have four categories: not at all, a little, quite a bit or very much, or as a modified visual analog scale going from 1 to 7. All scores are linearly transformed to a 0 to 100 scale. Higher scores on the functioning scales and the global quality of life scale indicate better functioning, while higher scores on the symptom scales reflect more problems. For the analysis, results on the global quality of life and the functioning scales were summarized in very poor (0–20), poor (21–40), intermediate (41–60), good (61–80) and very good (81–100). Symptom scales were summarized as none to slight (0–29), moderate (30–69) and severe (70–100).
Quality of life was assessed in a sample of 150 patients (77 transplanted with PBSC and 73 transplanted with BM) surviving without relapse at least six month after transplantation. These patients were asked to participate in the study when attending their post-transplant clinical control during a six-months period of recruitment. The patients responding in both groups were at similar time points after the transplant. The EORTC QLQ-C30 questionnaires were given directly to the patient by their personal physician. The patients returned the questionnaires either personally or by mail. None of the patients who had been asked to participate refused to collaborate in this study.
The QLQ-C30 responses were scored and analyzed according to the scoring manual provided by the EORTC Study Group on Quality of Life.18
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Figure 1. Cumulative incidence of grades II-IV (Figure 1A) and III-IV (Figure 1B) acute graft-versus-host disease according to stem cell source.
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Table 2. Multivariate analysis for aGvHD grades II-IV and III-IV. Only variables with a p value <0.2 in the univariate analysis are shown.
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Chronic graft-versus-host disease
We found a significantly higher incidence of extensive chronic GvHD after PBSC transplantation (28% vs. 15.6% for BM recipients; HR: 2.11; 95% CI: 1.43–3.11; p<0.001). In multivariate analysis, the use of PBSC was an independent risk factor for extensive chronic GvHD (HR: 2.18, 95%CI: 1.47–3.24; p<0.001).
Relapse
There were no significant differences in relapse incidences between PBSC and BM groups. The relapse incidence at three, five and nine years in the PBSC group was 26.3%, 28.7% and 29.4% vs. 26.8%, 29.7% and 35.2% in the patients treated with BM transplantation, respectively (p=0.688).
The differences in relapse incidences between both stem cell sources were not significant either in the early-disease group (22.4% for patients transplanted with PBSC vs. 21% those receiving BM at three years, 24.5% vs. 23.3% at five years and 25.6% vs. 31.6% at nine years, respectively; p=0.897) nor in the advanced disease group, (35.5% vs. 40.4% at three years, 48.5% vs. 49.2% at five years and 48.5% vs. 49.2% at nine years, respectively; p=0.415).
Transplant-related mortality
The cumulative incidence of mortality due to non-relapse causes was comparable between PBSC and BM: 28.3% vs. 27.2% at three years, 28.7% vs. 27.6% at five years and 34.4% vs. 28.9% at nine years, respectively (p=0.682). The transplant-related mortality (TRM) was also similar for patients with early phase of disease: 22.4% vs. 21% at three years, 24.5% vs. 23.3% at five years and 25.6% vs. 31.6% at nine years, respectively (p=0.897). Patients with advanced disease transplanted with PBSC or BM also showed comparable TRM cumulative incidence (35.5% vs. 40.4% at three years, 48.5% vs. 49.2% at five years and 48.5% vs. 49.2% at nine years, respectively, p=0.415). The day 100 TRM was also similar: PBSC 15% vs. BM 14.5%; p=0.682.
Overall survival
Univariate analysis showed a comparable overall survival for both groups (PBSC: 52% vs. BM: 53.1% at three years; 47.9% vs. 50.2% at five years and 39.8% vs. 48.9% at nine years, respectively; HR: 1.05; 95% CI: 0.86–1.28; p=0.621) (Figure 2). There were also no statistically significant differences between the two groups in patients with early phase disease (PBSC: 61.5% vs. BM: 61% at three years; 57.7% vs. 59.3% at five years and 56.7% vs. 57.4% at nine years, respectively; HR: 0.98; 95% CI: 0.75–1.28; p=0.906) or with advanced disease (PBSC: 29.3% vs. BM: 34.8% at three years, 24.7% vs. 29% at five years and 11.5% vs. 29% at nine years, respectively; HR: 1.19; 95% CI: 0.87–1.61; p=0.265).
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Figure 2. Overall survival according to stem cell source.
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Quality of life assessment
There was no statistical difference in global QoL between patients transplanted with PBSC and those transplanted with BM as a stem cell source: 73% of patients transplanted with PBSC obtained scores indicating a good/very good global health status/QoL, compared with 78.6% for patients receiving BM (p=0.434).
Patients transplanted with PBSC grafts showed statistically significant lower scores in relation to role functioning (work and household activities) and social functioning and a trend towards worse physical functioning. Also, they showed higher scores when measuring financial difficulties related to the treatment and health. The increased financial difficulties are probably due to the greater expenses related with the immunosuppressive drugs required for cGvHD treatment.
Table 3 shows the quality of life scores for both groups after answering the QLQ-C30.
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Table 3. Comparison of quality of life scores between the bone marrow and the peripheral blood groups.
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Interestingly, a lower relapse incidence and a higher DFS have been previously described for patients with advanced disease transplanted with PBSC allografts, suggesting that the higher incidence of chronic GvHD may be an important tool to control the minimal residual disease. However, it has also been suggested that an increased rate of cGvHD-related morbidity and mortality may obviate the long-term benefit. In the present study we found no differences between both stem cell sources in relapse incidence and DFS, even when we focused the analysis on patients transplanted in advanced disease phases. Similarly, we did not observe differences in overall survival at ten years between patients transplanted with BM or PBSC.
Our study offers new data concerning the QoL for long-term survivors. It is well known that extensive chronic GVHD can adversely affect quality of life,21–24 but none of the published randomized trials comparing BM and PBSC collected analyzable data on quality of life. We found that patients receiving PBSC had a worse role and social functioning, and also a trend towards a worse physical functioning. This impairment in functioning scales is probably due to the increased incidence of chronic GvHD after PBSC transplantation. Our results are in agreement with findings reported by Worel et al.21 which described significantly lower physical, role and social scores in patients experiencing chronic GvHD.
We can conclude from our study that, despite obtaining similar long-term survival and DFS, patients receiving PBSC have a higher incidence of both acute and chronic GvHD and worse social and role functioning indicators after quality of life assessment. These data are relevant for clinical practice, and can shift the choice of source from peripheral blood toward bone marrow in a proportion of cases. There are situations where PBSC offer advantages over BM such as weight unbalance between donor and recipient or major ABO incompatibility. However, on most occasions, BM offers a similar survival with less GvHD and a better quality of life. Additional studies to evaluate quality of life with long-term follow-up and a higher number of patients, are needed in order to clarify the role of the different stem cell sources in allogeneic hematopoietic stem cell transplantation. Until these studies clarify the situation, peripheral blood can not be considered equal to or better than bone marrow for an important proportion of patients.
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DG designed the study, analyzed data and wrote the paper; RdlC, JBN, IE and EC collected data, performed the quality of life studies, revised the article, and gave final approval; AI, AJ-V, CV, CM, DC, SB, DS, CS, JMR and JdlR collected data, revised the article and gave final approval.
The authors reported no potential conflicts of interest.
Funding: this study was financed by grant FIS PI080413 from the Fondo de Investigaciones Sanitarias, Instituto de Salud Carlos III, Ministerio de Sanidad y Consumo.
Received for publication February 4, 2009. Revision received March 18, 2009. Accepted for publication April 3, 2009.
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