Favorable outcome for infant acute lymphoblastic leukemia after hematopoietic stem cell transplantation.

Infants with acute lymphoblastic leukemia (ALL) have a poor prognosis when treated with standard chemotherapy. A subset of these infants, particularly those with mixed-lineage leukemia (MLL) rearrangements, has a high likelihood of relapse. Hematopoietic stem cell transplantation (HSCT) performed early in first remission may improve outcome. We present the results of 16 patients with infant ALL who were treated with HSCT in first remission. Six patients were < or =6 months of age at diagnosis, 11 had an initial white blood cell count of >50000/microL, and all patients with determinable cytogenetics had a high-risk karyotype [t(4:11) abnormality or other MLL rearrangement]. All patients received 150 cGy of total body irradiation for 8 doses (1200 cGy). Fifteen of 16 patients received etoposide at 1000 mg/m(2) as a continuous infusion over 24 hours and cyclophosphamide at 60 mg/kg/d for 3 days. Eight patients received HSCT from an HLA-identical sibling, and 8, from unrelated cord blood. Twelve (75%) patients remain long-term survivors (median follow-up, 4.7 years). Two patients, 1 of whom had minimal residual disease at HSCT, died after relapse following HSCT. Two patients died of transplant-related causes. The HSCT was well tolerated; 15 patients achieved neutrophil engraftment at a median of 16 days. Acute and chronic graft-versus-host disease were minimal in these patients. These results support the use of HSCT in the treatment of infant ALL, especially when used as consolidation in first remission. The risk of relapse seems to be decreased with this approach. Further work is being performed to determine the long-term effects from this therapy.     

Impact of conditioning regimen intensity on outcome of allogeneic hematopoietic cell transplantation for advanced acute myelogenous leukemia and myelodysplastic syndrome.

We reviewed 136 patients with advanced acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) undergoing allogeneic transplantation to assess the impact of conditioning regimen intensity on outcome. Thirty-nine patients receiving nonmyeloablative stem cell transplantation (NST) were compared with 97 patients receiving myeloablative transplantation. Patients receiving NST were at high risk for treatment-related complications given that they were older, 57 vs 43 years (P < .001), and more likely had received previous or myeloablative transplantation (54% vs 2%; P < .0001). The cumulative risk of relapse was higher for patients after NST (61% vs 38%; P = .02). The 100-day mortality was less after NST (15% vs 32%) Overall survival (OS) at 2 years was 28% for NST and 34% for myeloablative transplantation (P = .89). Progression-free survival (PFS) at 2 years was 20% for NST and 31% for myeloablative transplantation (P = .31). Cox regression analysis showed that the intensity of the conditioning regimen had no effect on either OS or PFS. Despite the high-risk features of patients with advanced AML or MDS undergoing NST, OS and PFS in these patients was similar to those in patients receiving myeloablative transplantation. These results demonstrate that dose intensity plays a significant role in control of disease after transplantation, but that this benefit is negated by increasing treatment-related mortality. These results suggest that NST is a reasonable alternative for patients with advanced AML and MDS at high risk for complications after myeloablative transplantation.     

Occurrence,risk factors and outcome of adenovirus infection in adult recipients of allogeneic hematopoietic stem cell transplantation

BackgroundAdenovirus (ADV) infections can have a high mortality in immunocompromised patients and are difficult to treat.Objectives and study designWe retrospectively analyzed occurrence and risk factors of ADV infection in 399 adults with hematological disorders undergoing hematopoietic stem cell transplantation (allo-HSCT), focusing on alternative donor transplantation (ADT) and disseminated disease.ResultsADV infection occurred in 42 patients (10.5%). Disease was localized in 18 and disseminated in 6 patients. ADV infection was observed in 15% after ADT, performed in 29% of all recipients, and was less frequent (6%) in T-cell-replete (TCR) haploidentical transplantation using post-transplantation cyclophosphamide (PTCY) than in other ADT protocols. Lower age, the use of alternative donor grafts and acute graft-versus-host disease (GvHD) ≥ grade II were risk factors for ADV infection.After failure of standard antiviral treatment, three patients with disseminated ADV disease received one dose of ADV-specific T cells, resulting in virological response in 2/3 patients, clearance of ADV viremia in 2/2 patients, and survival of 1/3 patients; both patients with pneumonia died.ConclusionsADV infection was of moderate occurrence in our adult recipients of allo-HSCT despite a high proportion of potential high-risk patients receiving ADT. TCR strategies using PTCY might limit ADV complications in haploidentical transplantation. Despite feasible adoptive therapy strategies, outcome of disseminated disease remains dismal.     

Invasive mold infections in acute leukemia patients undergoing allogeneic hematopoietic stem cell transplantation

Background/purposePatients with acute leukemia undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) are exposed to high risk of developing invasive fungal infections, and the invasive mold infections (IMIs) are becoming more and more common after transplantation. Here, we conducted a retrospective study to analyze demographics, microbiology, and risk factors for IMIs development in adult acute leukemia patients undergoing allo-HSCT.MethodsWe reviewed 245 adult acute leukemia patients undergoing allo-HSCT from January 2003 to December 2014. Clinical characteristics including age, sex, conditioning regimens, European Group for Blood and Bone marrow Transplantation (EBMT) risk score, and presence of acute graft-versus-host disease (aGVHD) or chronic GVHD (cGVHD) were collected and analyzed. Cox proportional hazard model was adopted to explore the independent risk factors for IMIs developments.ResultsSeventeen of 245 patients developed IMIs during the study period. The cumulative incidence of IMIs in this cohort was 8.7% and 16.8% at 6 and 12 months, respectively, with Aspergillus species being the most common pathogen. The significant risk factors predicting IMIs were unrelated donor transplantation (hazard ratio [HR] 5.11), smoking (HR 3.55), EBMT risk score > 2 (HR 4.22), and moderate to severe cGVHD (HR 3.76).ConclusionsWe identified four risk factors-unrelated donor transplantation, smoking, EBMT risk score >2 and moderate to severe cGVHD to predict IMIs among acute leukemia patients undergoing allo-HSCT. This cohort study suggests early identification of high-risk patients and to provide better prevention strategies would reduce the incidence and severity of IMIs in these patients.     

Allogeneic stem cell transplantation for Philadelphia chromosome-positive acute lymphoblastic leukemia.

The prognosis for adult and pediatric patients with Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) treated with chemotherapy alone is extremely poor. An overview of the biology and clinical features of Ph+ ALL is presented in this review. The experience with chemotherapy and autologous stem cell transplantation (SCT) is summarized. Allogeneic SCT offers a curative option for patients who have an appropriately matched donor. Variables affecting outcome after allogeneic SCT, including age, stage of disease, source of stem cells, preparatory regimen, and molecular and cytogenetic details, are analyzed. The City of Hope/Stanford University experience with fractionated total body irradiation and high-dose etoposide is described, and future directions for monitoring and treating minimal residual disease are discussed.     

Harnessing dendritic cells to improve allogeneic hematopoietic cell transplantation outcome

In clinical practice, hematopoietic cell transplantation (HCT) is now recognized as a powerful means of delivering effective cellular immunotherapy for malignant and non-malignant diseases. In patients with severe hematological malignancies, the success of allogeneic HCT is largely based on immunologic graft-versus-tumor (GVT) effects mediated by allogeneic T lymphocytes present in the graft. Unfortunately, this beneficial effect is counterbalanced by the occurrence of graft versus host reactions directed against normal host tissues resulting in graft versus host disease (GVHD), a potentially life-threatening complication that limits the success of allogeneic HCT. Therefore, while preserving beneficial GVT effects, a major objective in allogeneic HCT is the prevention of GVHD. Studies in the last decade revealed the central role of dendritic cells and macrophages in modulating graft versus host immune reactions after allogeneic HCT. In this review, we summarize recent progress and potential new therapeutic avenues using dendritic cell-based strategies to improve allogeneic HCT outcome.     

Haploidentical/mismatched hematopoietic stem cell transplantation without in vitro T cell depletion for T cell acute lymphoblastic leukemia

The outcome of T cell acute lymphoblastic leukemia (T-ALL) is poorly understood. Allogeneic hematopoietic stem cell transplantation (HSCT) remains 1 of the best options to cure T-ALL. However, many patients cannot find an HLA-matched donor. Our institute established a new protocol for haplo-identical HSCT. Busulfan, cyclophosphamide, cytosine arabinoside, and methyl CCNU plus antithymocyte globulin was used for conditioning therapy. Seventy-two patients diagnosed with T-ALL underwent transplantation from haploidentical donor family members. The incidence rates of grades II to IV acute graft-versus-host disease (aGVHD) and of grades III and IV aGVHD were 49% ± 12% and 19% ± 12%, respectively. The cumulative incidence rate for chronic GVHD (cGVHD) at 2 years after HSCT was 41% ± 12%. After a median follow-up of 12 months, 15 patients had relapsed, 14 died from relapse, and 41 patients were still alive without disease recurrence. The probability of leukemia-free survival (LFS) was 44.2% ± 7.4% at 3 years. Patients transplanted during their first complete remission (CR1) had a lower relapse rate (18.8% versus 37.5%, P = .049, with a relative risk [RR] = 0.247, P = .007), a lower nonrelapse mortality (NRM) rate (16.6% versus 50.0%, P = .046, with an RR = 0.279, P = .024), and better LFS (54.8% versus 12.5%, P = .001, with an RR = 0.315, P = .004) compared with patients transplanted beyond CR1. This study confirmed that haploidentical/mismatched HSCT could be an alternative treatment choice for T-ALL.     

Demodicidosis simulating acute graft-versus-host disease after allogeneic stem cell transplantation in one patient with acute lymphoblastic leukemia

One important differential diagnosis of facial erythema in a patient receiving an allogeneic bone marrow transplant (BMT) is acute graft-versus-host disease (GVHD). Demodex folliculorum has been rarely implicated in the development of facial rashes in immunosuppressed patients, including BMT recipients. We report the case of a patient, suffering from acute lymphoblastic leukemia, who after bone marrow transplantation developed a facial rash due to D. folliculorum mimicking GVHD. Differential diagnosis of facial rashes and demodicidosis after BMT is reviewed.     

Autologous versus allogeneic unrelated donor transplantation for acute lymphoblastic leukemia: comparative toxicity and outcomes.

For patients with high-risk or relapsed acute lymphoblastic leukemia (ALL) lacking a related histocompatible donor, autologous (Auto) and unrelated donor (URD) transplantation are available options. We compared outcomes and toxicities in 712 patients with ALL (517 URD, 195 Auto) in first complete remission (CR1) or second complete remission (CR2) who underwent transplantation. All patients were <50 years old, although URD patientswere younger (median age, 14 versus 18 years, P < .002). The proportion of patients in CR1 versus CR2 was similar (36% versus 38%, P = .57), but more URD recipients than Auto recipients had high-risk karyotypes (25% versus 13%, P = .003) and white blood cell (WBC) counts > or =50 x 10(9)/L (33% versus 14%, P < .001). Engraftment was similar in URD and Auto recipients. Ex vivo purging delayed but did not prevent engraftment after Auto transplantation. Transplantation-related mortality was higher after URD transplantation (42%+/-8%) than after Auto transplantation (20%+/-12%) in CR1 (P = .004) and also in CR2. Conversely, relapse was more frequent after Auto transplantation in CR1 (Auto, 49%+/-12% versus URD, 14%+/-5%) and CR2 (64%+/-8% versus 25%+/-5%) (P < .0001). These findings showed net similar outcomes for these 2 transplantation choices. Transplantation in CR1 yielded similar 3-year survival rates for URD (51%+/-7%) and Auto (44%+/-12%), as did transplantation in CR2 (40%+/-6% versus 32%+/-9%, respectively). Multivariate regression analysis identified significantly better disease-free survival after the first 6 months in matched URD versus Auto in younger patients, in those in CR2 with CR1 >1year, WBC <50 x 10(9)/L, performance status > or =90%, and in those who have undergone transplantation since 1995. These comparative data suggest that both matched URD and Auto transplantation can yield extended survival. Although URD transplantation offers substantially better protection against leukemic relapse, improvements in allotransplantation safety and refinements in patient selection are required to better aid treatment decision making for the best overall survival.     

Risk factors for moderate-to-severe chronic graft-versus-host disease after allogeneic hematopoietic stem cell transplantation.

Among 810 consecutive hematopoietic stem cell transplantation (HSCT) patients, 679 survived more than 3 months and were evaluated for chronic GVHD. The aim of this study was to find predisposing factors increasing the risk of development of moderate-to-severe chronic GVHD. Many of the donors were HLA-identical siblings or related (n = 435), 185 were HLA-matched unrelated, and 59 were mismatched related or unrelated donors. Most of the patients had a hematological malignancy (n = 568), but 111 patients with a nonmalignant disease were included. Two hundred twenty-three patients (33%) developed mild, 41 (6%) moderate, and 15 (2.2%) severe chronic GVHD. The 5-year probability of development of moderate-to-severe chronic GVHD was 10%. We analyzed 30 potential risk factors for chronic GVHD. In the multivariate analysis, acute GVHD) grades II to IV (relative hazard [RH], 2.30; 95% CI, 1.29-4.10; P = .005), CML diagnosis (RH, 2.37; CI, 1.38-4.08; P = .002) and transplantation from an immunized female donor to a male recipient (RH, 2.16; CI, 1.14-4.11; P = .02) were independent risk factors for moderate-to-severe chronic GVHD. Recipient age also was significant (RH, 2.42; CI, 1.23-4.77; P = .01) if CML was not included in the analysis. In patients with no risk factors, the 5-year probability of development of moderate-to-severe chronic GVHD was 5%. In patients with 1 risk factor, the probability was 13%; 2 risk factors, 23%; and 3 risk factors, 45%. Among patients who developed chronic GVHD (n = 279), acute GVHD grades II to IV (RH, 2.18; CI, 1.23-3.86; P < .01) was the only predictive factor for moderate-to-severe chronic GVHD versus mild disease. Patients with previous acute GVHD grades II to IV may benefit from more aggressive initial treatment. This possibility would have to be examined in clinical trials.     

地西他滨联合造血干细胞移植治疗骨髓增生异常综合征转化急性白血病

背景：由骨髓增生异常综合征转化的急性白血病为难治白血病,临床疗效差,缓解率低,生存期短,因此探索新的有效治疗方法极为重要。 目的：观察地西他滨联合造血干细胞移植治疗骨髓增生异常综合征转化急性白血病的临床疗效及并发症。 方法：骨髓增生异常综合征转化的急性髓细胞白血病患者1例,先后予2个疗程地西他滨及异基因造血干细胞移植,观察临床疗效、地西他滨的毒副作用及移植相关并发症。 结果与结论：经2个疗程地西他滨治疗后,达到完全缓解,主要不良反应为骨髓抑制并发感染,该患者再接受异基因造血干细胞移植后获得无病生存213 d,移植过程中出现急性移植物抗宿主病及肺部感染。结果提示地西他滨联合造血干细胞移植治疗骨髓增生异常综合征转化急性白血病获得良好效果,毒副作用及相关并发症可控制,为临床上骨髓增生异常综合征转化急性白血病的治疗提供了新方法。     

异基因造血干细胞移植后的相关并发症及危险因素

背景：有效预防和治疗异基因造血干细胞移植后并发症是提高患者存活率的重要因素。 目的：分析异基因造血干细胞移植后相关并发症的发生和危险因素。 方法：应用文献检索的方法获取异基因造血干细胞移植后相关并发症研究的文献,对符合研究标准的文献进行深入的数据分析,文章选取异基因造血干细胞移植后极易发生的并发症进行分析,如肺部并发症、真菌性败血症、巨细胞病毒感染以及中枢神经系统并发症等。 结果与结论：异基因造血干细胞移植后易出现肺部并发症,而且死亡率较高,肺部并发症的发病机制可能与移植物抗宿主病和巨细胞病毒抗原血症相关。异基因造血干细胞移植后真菌性败血症病原菌以假丝酵母菌属为主,死亡率较高,应二级预防性和早期经验性抗真菌治疗。更昔洛韦、膦甲酸钠对异基因造血干细胞移植后巨细胞病毒感染的治疗有效。中枢神经系统并发症在异基因造血干细胞移植后发生率较低,但在治疗过程也不容忽视。异基因造血干细胞移植后相关并发症的发生与多种危险因素有关,在临床治疗过程中要对相关因素采取预防措施,减少并发症的发生,提高患者的存活率。     

Second malignancies after allogeneic hematopoietic cell transplantation.

Allogeneic hematopoietic cell transplantation (allo-HCT) may prolong life and cure patients suffering from otherwise fatal diseases. However, the growing population of long-term survivors has led to the realization of multiple long-term complications, including the risk of second malignancies. Compared to the autologous setting, allo-HCT carries a much higher risk of posttransplant lymphoproliferative disorder (PTLD), which usually occurs within the first year after allo-HCT and is strongly associated with the Epstein-Barr virus (EBV). Treatment-related myelodysplastic syndromes (tMDS) and second leukemias are extremely rare. Both autologous and allo-HCT carry increased risks for second solid malignancies (SSM). The cumulative incidence of SSM continues to increase in each of the largest studies with as much as 20 years of follow-up, likely related to the long latency of radiation-related SSM. Systematic, prospective monitoring, vigilant screening processes, and well-maintained survivorship clinics and databases are absolute necessities, and should be included in the infrastructure of individual transplant centers and networks, with mandatory periodic reporting of second malignancy incidences. Primary care and transplant physicians alike must be aware of the risk of second malignancies after allo-HCT. Most importantly, guidelines should be developed in regard to screening and prevention of second malignancies, so that physicians can provide state-of-the-art counsel and care for the benefit of our patients.     

非清髓性异基因造血干细胞移植治疗高龄白血病

背景：非清髓异基因造血干细胞移植减轻了预处理强度,减少了移植相关的死亡。 目的：分析非清髓性异基因造血干细胞移植治疗老年急性白血病的疗效及其安全性。 方法：71岁急性单核细胞白血病M5b 患者1例,行非清髓性异基因造血干细胞移植。供者为患者同胞弟弟,60岁,HLA 5个位点相合,ABO血型相同。预处理用药包括采用氟达拉滨、塞替派、环磷酰胺和马利兰针剂。移植物抗宿主病预防用抗胸腺球蛋白、巴利昔单抗、环孢素A、麦考酚酯肠溶片及丙种球蛋白,移植后并发症防治和支持治疗：更昔洛韦防治巨细胞病毒感染、前列腺素E1、丹参、肝素及熊去氧胆酸防治肝静脉闭塞症,预处理后外周血中性粒细胞低于0.5×109 L-1时开始予粒细胞集落刺激因子5 μg/(k g•d)促进造血重建。必要时输注辐照的浓缩红细胞和血小板,供者采用粒细胞集落刺激因子,连用 7 d,第6,7天采集外周血造血干细胞,当天输注给患者。 结果与结论：移植后28 d完成造血重建。移植后50 d,行STR检测结果显示供受者100%一致。移植后+20~30 d陆续出现“出血性膀胱炎”、“败血症(洋葱伯克霍尔德菌胞菌)”,移植后2个月出现黄疸、肝功能损害,诊断“急性移植物抗宿主病Ⅲ度(肝脏,3级) ”,经过抗感染、保肝、调整免疫抑制药物治疗后病情缓解。结果表明采用以氟达拉滨为基础的非清髓性外周血造血干细胞移植治疗有多种合并症老年急性白血病是一种有效安全的方法。     

Myeloperoxidase immunoreactivity in adult acute lymphoblastic leukemia.

To evaluate the frequency and significance of myeloperoxidase positivity in adult acute lymphoblastic leukemia (ALL), bone marrow biopsy material from 82 adults with ALL was evaluated with a polyclonal myeloperoxidase (pMPO) antibody. Nineteen cases (23%) demonstrated evidence of pMPO immunoreactivity. Positive cases were precursor B-cell lineage, and CD13 or CD15 expression was more frequent than in the pMPO-negative cases. A subset of pMPO-positive cases studied with a monoclonal MPO antibody was negative. Western blot analysis using the pMPO antibody showed the expected 55-kd band for myeloperoxidase in pMPO-positive and pMPO-negative ALLs, suggesting a lack of specificity of this antibody in ALL. Forty-two percent (8/19) of the pMPO-positive ALL cases demonstrated evidence of t(9;22) by either karyotype or polymerase chain reaction analysis. The pMPO-positive ALLs had a lower frequency of extramedullary disease than the pMPO-negative group and a trend toward improved overall survival compared with the pMPO-negative group. Immunoreactivity with pMPO in adult ALL may lead to an incorrect interpretation of biphenotypic acute leukemia using a recently described scoring system, and a revision to that scoring system is proposed to accommodate pMPO-positive ALL.     

白消安在非亲缘异基因造血干细胞移植预处理中的应用

背景：口服白消安剂型胃肠道吸收不稳定,影响异基因造血干细胞疗效且毒性增加。静脉剂型白消安在国内最近几年用于临床,但在非亲缘异基因移植预处理中应用的相关报道甚少。 目的：探讨静脉剂型白消安在非亲缘异基因造血干细胞移植预处理中应用的疗效并观察其毒副作用。 方法：14例非亲缘异基因干细胞移植采用静脉剂型白消安联合环磷酰胺预处理方案,18例亲缘异基因干细胞移植采用口服白消安联合环磷酰胺预处理方案,观察两组造血重建、植入率等疗效指标及胃肠道反应、口腔黏膜炎、出血性膀胱炎、肝功能损害、移植物抗宿主病等相关毒性指标。 结果与结论：两组患者植入率均为100%。静脉剂型组肝脏毒性、口腔黏膜炎发生率明显低于口服剂型组(14% vs. 67%,7% vs. 55%),差异均有显著性意义(P < 0.01),而胃肠道反应、出血性膀胱炎、造血重建、急性移植物抗宿主病、局限性移植物抗宿主病等方面差异均无显著性意义(P > 0.05)。结果可见静脉剂型白消安应用于非亲缘异基因造血干细胞移植预处理可获得满意疗效,且毒副反应少。     

CTLA-4 polymorphism and clinical outcome post allogeneic hematopoietic stem cell transplantation

CTLA-4 inhibitory molecule plays an important role in regulating T cell activation. It is considered a crucial element in keeping the immune balance and has been implicated in cancer, autoimmunity and transplantation immunology. Inconsistent observations are reported regarding its association with hematopoietic stem cell transplantation (HSCT). Genotyping of CTLA-4 was performed in recipients and their HLA-matched donors for +49A/G and CT60 polymorphisms (80 and 94 pairs, respectively) using PCR-RFLP. No association was encountered between both polymorphisms in patients and donors and acute or chronic graft versus host disease. Significant association was observed between recipient +49A/G G allele and lower disease-free survival and overall survival compared to AA genotype (HR: 2.17, p = 0.03, 95% CI: 1.05–4.48 and HR: 2.54, p = 0.01, 95% CI: 1.16–5.54), respectively. Our results suggest that CTLA-4 genotyping may predict outcome in patients post HSCT. To validate our results, further studies on a larger cohort are needed.     

Comparison of autologous and allogeneic bone marrow transplantation for treatment of high-risk refractory acute lymphoblastic leukemia

Chemoradiotherapy and transplantation of bone marrow from matched sibling donors have been useful for the treatment of acute lymphoblastic leukemia in patients with a poor prognosis but are not available to some two thirds of patients who do not have a matched allogeneic donor. We undertook this study to compare autologous and allogeneic marrow transplantation in the treatment of such cases. We treated 91 patients with high-dose chemoradiotherapy and followed them for 1.4 to 5 years. Forty-six patients with an HLA-matched donor received allogeneic marrow, and 45 patients without a matched donor received their own marrow taken during remission and purged of leukemic cells with use of monoclonal antibodies. Bone marrow engraftment occurred earlier in patients who received autologous marrow. Recipients of autologous marrow had shorter hospital courses, with significantly fewer peritransplantation deaths than recipients of allogeneic marrow. Post-transplantation relapse of leukemia was the most frequent cause of treatment failure; relapses occurred in an estimated 37 percent of patients with allogeneic grafts in whom graft-versus-host disease developed, 75 percent of patients with allogeneic grafts in whom graft-versus-host disease did not develop, and 79 percent of patients who received autologous grafts. The interval before relapse was significantly shorter in the autologous-marrow group than in the allogeneic-marrow group. Recipients of autologous and allogeneic marrow whose first pretransplantation remissions were short (less than 18 months) had eventual outcomes similar to those whose first remissions were longer than 18 months. Patients with a first remission lasting less than 18 months had an outcome better than that expected with chemotherapy alone. The fractions of "cured" patients were estimated to be 20 percent in the autologous-marrow group and 27 percent in the allogeneic-marrow group--not a significant difference, but because of the limited statistical power of the study, the question of long-term disease-free survival must still be considered open.