Marrow transplantation for Fanconi anaemia: conditioning with reduced doses of cyclophosphamide without radiation

Successful Outcome With Fludarabine-Based Conditioning Regimen for Hematopoietic Stem Cell Transplantation From Related Donor in Fanconi Anemia: A Single Center Experience From Turkey

BACKGROUND

Fanconi anemia (FA) is a heterogeneous autosomal recessive (and rarely X linked) disorder, which is characterized by congenital malformations, progressive bone marrow failure, and predisposition to malignancies. Hematopoietic stem cell transplantation (HSCT) is the only definitive treatment for the hematological manifestations in FA.

PROCEDURE

Twenty-seven patients with FA underwent HSCT using fludarabine (Flu) based regimen at our center between April 2004 and May 2014. One patient who developed acute leukemia before HSCT was excluded from the study. The remaining 26 patients were included. The median age of the patients at the time of transplantation was 9.6 years (range 5.6-17.0 years) and male/female ratio was 19/7. Donors were Human leukocyte antigen (HLA)-identical sibling in 18 patients, HLA-identical other relatives in six patients, and HLA 1-antigen mismatched sibling in two patients. Conditioning regimen consisted of Flu, cyclophosphamide, and antithymocyte globulin.

RESULTS

All patients engrafted but one developed poor graft function and underwent second HSCT. Acute graft versus host disease (GVHD) (≥grade 2) occurred in two patients (7.6%) and chronic GVHD in one patient (3.9%). Three patients developed venoocclusive disease (11.5%). Survival rate was 96.2% (25/26) at a median follow-up of 54 months (10-131 months) and all patients who survived were in good clinical condition. None of the patients developed secondary malignancy during the follow-up period.

CONCLUSIONS

The present study from Turkey, a middle-income country, shows successful transplant outcome with low toxicity using Flu-based conditioning in patients with FA who underwent HSCT from HLA-related donors.

How I treat MDS and AML in Fanconi anemia

Fanconi anemia (FA) is the most frequent inherited cause of bone marrow failure (BMF). Most FA patients experience hematopoietic stem cell attrition and cytopenia during childhood, which along with intrinsic chromosomal instability, favor clonal evolution and the frequent emergence in their teens or young adulthood of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). To early identify and further predict bone marrow (BM) clonal progression and enable timely treatment, the follow-up of FA patients includes regular BM morphological and cytogenetic examinations. Allogeneic hematopoietic stem cell transplantation (HSCT) remains the only curative treatment of FA patients with MDS or AML. Although questions remain concerning HSCT itself (including the need for pretransplant chemotherapy, the best conditioning regimen, and the optimal long-term follow-up of such patients especially regarding secondary malignancies), clonal evolution in the absence of significant BM dysplasia and blast cells can be difficult to address in FA patients, for whom the concept of preemptive HSCT is discussed. Illustrated by 3 representative clinical vignettes showing specific features of MDS and AML in FA patients, this paper summarizes our practical approach from diagnosis through treatment in this particular situation.

Fanconi Anemia: Overview of the Disease and the Role of Hematopoietic Transplantation

Fanconi anemia (FA) is an inherited bone marrow failure syndrome characterized by congenital abnormalities and chromosomal breakages with the occurrence of hematological and solid malignancies. FA is the most common type of inherited bone marrow failure and poses tremendous challenges. FA patients are uniquely hypersensitive to hematopoietic stem cell transplantation (HSCT) conditioning agents due to the underling chromosomal instability. HSCT has shown important progress in the last years, especially after the introduction of fludarabine and the reduction of cyclophosphamide in the preparative regimen. For patients with HLA-identical-related donors HSCT should be performed as first-line therapy, for patients with alternative donors HSCT remains a therapy with increased morbidity and mortality.

Inherited cancer syndromes in children and young adults

Geneticists estimate that 5% to 10% of all cancers diagnosed in the pediatric age range occur in children born with a genetic mutation that directly increases their lifetime risk for neoplasia. However, despite the fact that only a fraction of cancers in children occur as a result of an identified inherited predisposition, characterizing genetic mutations responsible for increased cancer risk in such syndromes has resulted in a profound understanding of relevant molecular pathways involved in carcinogenesis and/or resistance to neoplasia. Importantly, because most cancer predisposition syndromes result in an increased risk of a small number of defined malignancies, personalized prophylactic surveillance and preventive measures can be implemented in affected patients. Lastly, many of the same genetic targets identified from cancer-prone families are mechanistically involved in the majority of sporadic cancers in adults and children, thereby underscoring the clinical relevance of knowledge gained from these defined syndromes and introducing novel therapeutic opportunities to the broader oncologic community. This review highlights the clinical and genetic features of many of the known constitutional genetic syndromes that predispose to malignancy in children and young adults.

HSCT for Fanconi anemia in children: factors that influence early and late results

Fanconi anemia (FA) is a rare autosomal recessive disease characterized by congenital abnormalities, cancer predisposition and progressive BM failure. FA patients present spontaneous and induced chromosome breakage. Hematopoietic SCT (HSCT) represents the unique therapeutic option to restore normal hematopoiesis when marrow failure or clonal hematopoietic abnormality occurs. Conventional myeloablative conditioning regimen, especially including a high dose of irradiation, appeared strongly toxic for FA patients. Then, reduced-intensity conditioning regimens were developed successfully for those patients. However, TRM still remained higher than for other HSCT indications. The development of fludarabine containing a non-myeloablative conditioning regimen appears to be a major progress. Long-term follow-up is absolutely necessary.

HLA-matched sibling hematopoietic stem cell transplantation for fanconi anemia: comparison of irradiation and nonirradiation containing conditioning regimens

Related to the underlying DNA repair defect that is the hallmark of Fanconi anemia (FA), preparatory regimen-related toxicities have been obstacles to hematopoietic cell transplantation (HCT). In an attempt to decrease the risk and severity of regimen-related toxicities, nonirradiation regimens have been explored. The aim of this study is to compare outcomes after irradiation and nonirradiation regimens in 148 FA patients and identify risk factors impacting upon HCT outcomes. Hematopoietic recovery, acute and chronic graft-versus-host disease (aGVHD, GVHD), and mortality were similar after irradiation and nonirradiation regimens. In both groups of recipients aged >10 years, prior use of androgens and cytomegalovirus seropositivity in either the donor or recipient were associated with higher mortality. With median follow-ups >5 years, the 5-year probability of overall survival, adjusted for factors impacting overall mortality was 78% and 81% after irradiation and nonirradiation regimens, P = .61. In view of the high risk of cancer and other radiation-related effects on growth and development, these results support the use of nonirradiation preparatory regimens. As the peak time for developing solid tumors after HCT is 8 to 9 years, longer follow-up is required before definitive statements can be made regarding the impact of nonirradiation regimens on cancer risk.

HLA-matched related donor hematopoietic cell transplantation in 43 patients with Fanconi anemia conditioned with 60 mg/kg of cyclophosphamide

Cells from Fanconi anemia (FA) patients are hypersensitive to alkylating agents and radiation traditionally used as conditioning regimens for marrow cell transplantation, and patients experience serious toxicities. To reduce toxicities, we used progressively lower doses of cyclophosphamide (CY) for conditioning. Here, we report the results in 43 FA patients who received marrow transplantation from HLA-matched related donors (37 siblings and 6 other relatives). Conditioning consisted of 15 mg CY/kg/day for 4 days along with Mesna. Methotrexate and cyclosporine were given for graft-versus-host disease (GVHD) prophylaxis. Forty patients (93%) are alive with a median follow-up of 3.7 (range 0.6 to 7.9) years. One patient with primary graft failure was successfully retransplanted. Three of 4 patients with late graft failures were retransplanted, and 2 of those are alive; 1 died before a second marrow graft. Twelve patients including 3 with rejection had cytogenetic abnormalities in their marrow cells before transplantation. Acute grade II-III and chronic GVHD (aGVHD, cGVHD) were seen in 17% and 28.5% of patients, respectively. These results confirm and extend our previous observations that conditioning with 60 mg CY/kg allows for sustained engraftment of HLA-matched related marrow grafts in most FA patients and is associated with low toxicity, low incidences of aGVHD and cGVHD, and excellent long-term survival.

Bone marrow transplantation from matched related donors for patients with Fanconi anemia using low-dose busulfan and cyclophosphamide as conditioning

Seventeen patients with Fanconi anemia (FA) underwent allogeneic bone marrow transplantation (BMT) from matched related donors (MRD) between January 1999 and June 2003. Median age at BMT was 11 years. Conditioning regimen consisted of low-dose cyclophosphamide (CY; 40 mg/kg) and busulfan (BU; 6 mg/kg) with the addition of lymphoglobulin (20 mg/kg) in two patients. Graft-versus-host disease (GVHD) prophylaxis included cyclosporine A (CsA) and methotrexate (MTX; 5 mg/m(2) at day 1, 3, 6). All patients engrafted (for an absolute neutrophil count >0.5 x 10(9)/L) after a median time of 12 days (range 10-16 days). Fourteen patients (82%) had sustained grafts, whereas three others (18%) rejected grafts between day +39 and +80 after transplantation. Two of them are still alive after successful second PBSC transplantation and one died. Acute and chronic GVHD occurred in 23% and 13% of patients, respectively. With a median follow-up of 16 months (range 3-53 months), survival rate was 72% and Karnofsky score was at least 90%. The low-dose BU/CY regimen, in FA patients allografted from an HLA-matched related donor, allowed engraftment with relative low toxicity. Early graft failure (GF) remains a problem and may require modification of this regimen.

Low-dose cyclophosphamide conditioning for haematopoietic cell transplantation from HLA-matched related donors in patients with Fanconi anaemia

Allogeneic haematopoietic cell transplantation (HCT) is effective therapy for Fanconi anaemia (FA). FA patients do not tolerate conditioning with 200 mg/kg of cyclophosphamide (Cy), typically used in aplastic anaemia. We previously published results of studies in which Cy doses were gradually reduced from 200 to 100 mg/kg. Here we update results of the initial studies and report data on 30 new patients conditioned with Cy either at 80 mg/kg (n = 7) or at 60 mg/kg (n = 23), given over 4 days before HCT from human leucocyte antigen-matched related donors. Methotrexate and cyclosporine were given for graft-versus-host disease (GVHD) prophylaxis. All seven patients given Cy at 80 mg/kg and 21 of 23 given Cy at 60 mg/kg had sustained engraftment, while two patients, both with clonal cytogenetics abnormalities, experienced graft failure. Grades 2-3 acute GVHD rates were 57% and 14% for patients given the higher and lower Cy doses, respectively (P = 0.001). Four patients given Cy at 80 mg/kg and 22 given Cy at 60 mg/kg were alive at a median of 47 (44-58) months and 16 (3-52) months, respectively. Cy at 60 mg/kg has acceptable toxicities, low rates of GVHD, and is sufficient for engraftment of related grafts in most FA patients.

Fludarabine, low-dose busulfan and antithymocyte globulin as conditioning for Fanconi anemia patients receiving bone marrow transplantation from HLA-compatible related donors

Allogeneic hematopoietic stem cell transplantation (SCT) from unaffected donors remains the only modality for the correction of hematological abnormalities in Fanconi anemia (FA) patients. We performed four HLA-matched related donor SCT using a novel irradiation and cyclophosphamide-free conditioning regimen. The protocol included fludarabine 150 mg/m(2), busulfan 4 mg/kg, and antithymocyte globulin 90 mg/kg. Graft-versus-host disease (GVHD) prophylaxis was cyclosporin A, MTX, and daclizumab. The engraftment and occurrence of full stable donor hemopoiesis was rapid in all cases with minimal short-term toxic complications. There were no infections or febrile episodes during the inpatient phase. Three patients developed acute GVHD grade I-II involving gut and skin and one patient progressed to extensive chronic GVHD. The preparative conditioning regimen is safe and associated with low organ toxicity and effective immunosupression for the stable engraftment in FA patients undergoing SCT with matched related donors.

Preparative therapies used for those with Fanconi's anemia undergoing stem cell transplants and subsequent engraftment rates

Fanconi anemia patients are often treated with stem cell transplants to prevent myelodysplastic changes or leukemic progression. A variety of preparative regimens have been utilized. A case of a 13-year-old child with Fanconi's anemia is presented to highlight the preparative therapy utilized, engraftment rates which have been seen and the incidence of graft-vs.-host disease (GvHD). A review of the literature suggests the most successful preparative therapies with the highest engraftment rates and also suggests the best GvHD regimens.

Reduced toxicity and prompt engraftment after minimal conditioning of a patient with Fanconi anemia undergoing hematopoietic stem cell transplantation from an HLA-matched unrelated donor

Given the profound sensitivity of patients with Fanconi anemia to conventional conditioning regimens before hematopoietic stem cell transplantation (HSCT), we developed a minimally toxic regimen consisting of 2 Gy total body irradiation, 90 mg/m2 fludarabine, and postgrafting immunosuppression with cyclosporine and mycophenolate to treat FA patients undergoing HSCT from HLA-matched unrelated donors. With over 10 months follow-up, our first patient has complete and sustained engraftment. Graft-versus-host disease was limited to mild skin and liver and moderate gut manifestations. We conclude that the approach is well tolerated and ideally suited to reduce regimen-related toxicities while achieving sustained engraftment.

Bone marrow donation in childhood: one donor's perspective

Allogeneic bone marrow transplantation is an established treatment modality for leukemia, hematologic disorders and inborn errors of metabolism. while the focus of attention is the transplant recipient, the bone marrow donor (often a sibling) is both physically and emotionally involved in the process. Few reports have been written from the donor's perspective, however. One of the authors of this report (G.P.) was a marrow donor as a child, and he reflects on this experience at the completion of his first year of training in medical school.

New approaches to hematopoietic cell transplantation for hematological diseases in children

Hematopoietic cell transplantation (HCT) has been used for more 30 years for the treatment of selected malignant and nonmalignant diseases. Traditionally, HCT for hematological disorders has relied on myeloablative conditioning before HLA-identical sibling bone marrow transplantation to correct the underlying hematological defect. Most children with hematological diseases who are referred to HCT have features that portend significant morbidity and early mortality. Among SAA patients who have HLA-identical sibling donors, younger patients with profound pancytopenia might be considered early for HCT. For others who lack sibling donors, patients who receive HCT from alternate sources have generally failed one or more courses of intensive immunosuppressive therapy and remain transfusion-dependent, some with hemosiderosis, red cell alloimmunization, and platelet transfusion refractoriness [44,46,48]. Currently, HCT for SCD is generally restricted to those who have experienced a significant sickle-related complication such as stroke, recurrent acute chest syndrome, or recurrent painful episodes [7,13]. In contrast, most reserve HCT in thalassemia for younger, Lucarelli class I, good-risk patients who have HLA-identical sibling donors, and veer away from older, high-risk thalassemics for whom transplantation is a riskier clinical intervention. For groups such as young adults with thalassemia major, HCT might become more widely applicable if its toxicity was reduced. Several approaches undergoing development include reduced-intensity conditioning and attempts to prevent GVHD. New methods to reduce the intensity and toxicity of conditioning as well as to use highly purified stem cells with the reduction in graft versus host disease may allow for the use of matched unrelated donors or haploidentical donors. This would serve to provide potentially more children who could benefit from stem cell transplantation with donors. These advances will hopefully lead to benefits for the majority of children who lack HLA-identical donors.

Chromosome instability syndromes

The chromosome instability syndromes, ataxia telangiectasia (A-T), Fanconi anaemia (FA) and Bloom syndrome (BS) have been known for many years. More recently Nijmegen breakage syndrome (NBS) and ataxia telangiectasia-like disorder (ATLD) have been identified. A-T, ATLD and NBS form a group of disorders all of which show very similar cellular features that result from the consequences of increased sensitivity to ionizing radiation (IR). They also share some clinical features, particularly A-T and ATLD, and all show an immunodeficiency. A-T and NBS both show a predisposition to lymphoid tumours. Fanconi anaemia can be caused by mutations in eight different genes, although the majority of mutations are accounted for by FANCA and FANCC. The very rare Bloom syndrome is caused by mutation in a single gene, BLM. An important feature which all of these disorders have in common is that the genes identified are involved in aspects of recombination repair of DNA damage.

[Bone marrow transplantation in Fanconi's anemia: report of seven cases]

OBJECTS

Follow-up of patients with Fanconi's anemia treated in our unit and review of the literature concerning bone marrow transplantation in Fanconi's anemia.

PATIENTS AND METHODS

Ten patients were followed in our unit for 20 years. We summarize their clinical features, treatment and clinical course.

RESULTS

Among the ten patients, seven received allogeneic marrow transplantation. Only two patients are still alive. Two transplanted patients died from complications shortly after the transplantation. Three other patients died later after the transplantation, two of them from oropharyngeal carcinomas.

DISCUSSION

The 5-year survival is about 70% in the transplantation with an HLA-identical sibling donor; it is only about 30% if the donor is an HLA-matched unrelated or mismatched related patient. Furthermore, retrospective studies have shown that the long-term outcome of carcinoma is a major complication after the transplantation.

CONCLUSION

Our series of patients with Fanconi's anemia reflects fairly faithfully the complications encountered in this disease. Although the improvement of the graft technique may decrease the rate of death due to transplantation, the long-term development of solid tumors remains a problem for which no solution has been suggested up to now.

Stem cell transplantation from HLA-matched related donor for Fanconi's anaemia: a retrospective review of the multicentric Italian experience on behalf of AIEOP-GITMO

Twenty-seven consecutive Italian patients with Fanconi's anaemia (FA) underwent stem cell transplantation (SCT) from an HLA-matched related donor in 10 Italian centres of the Associazione Italiana Ematologia ed Oncologia Pediatrica (AIEOP), Gruppo Italiano di Trapianto di Midollo Osseo (GITMO). Twenty-two patients (81.5%) were conditioned with low-dose (median 20 mg/kg) cyclophosphamide (Cy) and thoraco-abdominal or total body irradiation (median dose 500 cGy), five patients (18.5%) with high-dose Cy (median 120 mg/kg). Graft-vs.-host disease (GVHD) prophylaxis was carried out with cyclosporin A in 26 cases; methotrexate (MTX) was added in eight cases. One patient received MTX alone. The median follow-up was 36 months. Ninety-two percent of patients (25 out of 27) engrafted, grade II and III acute GVHD occurred in 28% and 8% of patients, respectively, with chronic GVHD in 12.5%. Conditioning-related toxicity was mild: 4% of patients had grade III mucositis, 7.4% had grade II haemorrhagic cystitis, 14.8% had grade III liver toxicity and 11.1% had grade III renal toxicity. Transplant-related mortality at 12 months was 19.2%, survival at 36 months was 81.5%, with a median Karnofsky score of 100%. No late tumours occurred after a mean follow-up of the survivors of 5 years. None of the studied variables significantly affected the survival, including conditioning regimen, acute GVHD and clinical non-haematological phenotype. Among the studied variables, only conditioning regimens containing high-dose Cy and the presence of genital abnormalities were significantly (P < 0.05) associated with an increased rate of acute GVHD. Our study demonstrates that the Italian FA patients undergoing SCT from an HLA-matched related donor have a very good outcome. These patients, when compared with others of different ethnic origin who underwent allogeneic bone marrow transplantation, showed a less severe non-haematological phenotype, raising the possibility that this milder phenotype may have, at least in part, contributed to the outcome. Our data may provide a useful tool for further studies aiming to correlate genotype with phenotype.

Fludarabine-based stem cell transplantation protocol for Fanconi's anaemia in myelodysplastic transformation

Allogeneic stem cell transplantation (SCT) represents the treatment of choice for severe bone marrow (BM) failure in patients with Fanconi's anaemia (FA). However, for FA patients developing leukaemic or myelodysplastic transformation, the results of SCT are much less encouraging. We present a 17-year-old girl with myelodysplastic transformation of FA (refractory anaemia with excess blasts) and oculocutaneous albinism, who was treated by sibling SCT using conditioning with fludarabine, cyclophosphamide (CY) and anti-lymphocyte globulin (ALG). She had rapid engraftment with no toxicity and no graft-versus-host disease (GVHD). Twenty-two months after SCT, she had 100% donor chimaerism on Southern blot analysis.

Bone marrow transplantation from matched siblings in patients with fanconi anemia utilizing low-dose cyclophosphamide, thoracoabdominal radiation and antithymocyte globulin

Nineteen patients with Fanconi anemia (FA) and bone marrow failure underwent bone marrow transplantation (BMT) from matched siblings. Median age at BMT was 8.7 years. Conditioning consisted of low-dose cyclophosphamide (CY 5 mg/kg x 4 days) and thoracoabdominal irradiation (TAI 400 cGy). Graft-versus-host disease (GVHD) prophylaxis was cyclosporin A (CsA) in 13 patients and CsA plus methotrexate in 6 patients. Antithymocyte globulin (ATG) was added in the pretransplant as well as the post-transplant period. All patients received high-dose acyclovir from day 2 pre-BMT to day 28 post BMT, and intravenous immunoglobulins (IVIG), 500 mg/kg weekly from day 7 pre-BMT to day 90 post BMT. No fungal prophylaxis was given. All patients engrafted, (median, 14 days for an absolute neutrophil count > or =0.5 x 10(9)/l; median, 37 days for platelet count > or =20 x 10(9)/l). Fourteen (74%) patients are alive with sustained engraftment and are transfusion independent. Three (16.6%) patients developed acute GVHD; none developed chronic GVHD. Five (26%) patients developed invasive fungal infections, and two (10%) developed fatal CMV disease. We believe the addition of ATG may have contributed to the increased incidence of severe life-threatening fungal and viral infections in our series.

Severe oesophagitis after allogeneic bone marrow transplantation for Fanconi's anemia

Allogeneic bone marrow transplantation (BMT) is an effective treatment for Fanconi's anemia (FA) but it requires a dose reduction of alkylating agents used for conditioning because of the increased sensitivity of FA cells to DNA cross-linking agents. Oesophageal damage has not previously been described as a complication after allogeneic BMT for this indication. We report five cases of severe oesophagitis with stenosis in patients transplanted for FA. It occurred either early, or more surprisingly, several years after BMT and could have easily been misdiagnosed. It could be explained by hypersensitivity of the FA mucosal cells to cytotoxic agents despite the reduced doses of cyclophosphamide and irradiation or to non diagnosed congenital abnormalities of the oesophagogastric junction. However, the evolution of the oesophageal disease was favorable in all, and none of the patients developed secondary cancer. Awareness of this complication will lead to earlier diagnosis and treatment of oesophageal stenosis and related malnutrition.

Fludarabine-based protocol for human umbilical cord blood transplantation in children with Fanconi anemia

PURPOSE

A novel conditioning regimen of fludarabine monophosphate (FLM), anti-T-lymphocyte globulin (ATG), and low-dose cyclophosphamide with no irradiation for human umbilical cord blood transplantation (HUCBT) for the treatment of Fanconi anemia (FA) is described.

PATIENT AND METHODS

A 12-year-old girl with FA received a human umbilical cord blood transplant from a fully matched sibling donor. After the HUCBT, the patient was given granulocyte colony stimulating factor in combination with erythropoietin. Pretransplant conditioning consisted of FLM (30 mg/m2/d) from day -10 to day -5, cyclophosphamide (10 mg/kg/d) on day -7 and -6, and rabbit ATG (ATG-Frasenius, 10 mg/kg/d) from day -4 to day -1. Cyclosporin A (3 mg/kg/d) was administered from day -1 as graft-versus-host disease prophylaxis. Cord blood from a sibling donor was used as a source of hematopoietic stem cells.

RESULTS

Engraftment was normal and sustained. The regimen was well tolerated with very mild toxicity and no major transplant-related complications or >grade II graft-versus-host disease. Chimerism was 100% donor origin as determined by restriction fragment length polymorphism.

CONCLUSIONS

It is possible to achieve sustained engraftment and only mild toxicity in FA after HUCBT with a conditioning regimen of FLM, ATG, and cyclophosphamide with no irradiation. These preliminary results with this novel conditioning protocol are encouraging and should be evaluated in a larger group of patients with FA undergoing HUCBT.

Transplantation for Fanconi's anaemia: long-term follow-up of fifty patients transplanted from a sibling donor after low-dose cyclophosphamide and thoraco-abdominal irradiation for conditioning

We describe the long-term follow-up of 50 Fanconi's anaemia patients who were transplanted from a related donor with a median follow-up of >6 years. The survival estimate was 74.4% at 54 months and 58.5% at 100 months. All patients were conditioned with low-dose cyclophosphamide and thoraco-abdominal irradiation. Acute graft-versus-host disease (GvHD) of grade II or more developed in 26 patients and chronic GvHD developed in 30/43 (69.9%) patients. The survival of patients without chronic GvHD (n = 13) was 100%. In addition to chronic GvHD, 20 pre-transplant transfusions was shown to have an adverse impact on survival by multivariate analysis (relative risk = 7.08, P = 0.0003). Prospective follow-up of growth and endocrine function could be performed in 31 patients. Of 20 boys, six have already reached normal puberty within the expected time. Among the 11 girls, three were at the pubertal age at the time of analysis. Growth retardation was common, whereas late complications (e.g. peripheral hypothyroidism, cataract) were rare. However, the most important long-term complication was the occurrence of cancer in seven patients (8-year projected incidence 24%). Among the 32 survivors, 27 (84.5%) had a normal and four a moderately reduced performance status, and all achieved complete engraftment with donor cells. Therefore transplantation was able to cure these patients who remain at high risk for developing late complications. Clearly, a genetic predisposition and chronic GvHD could have led to the development of these cancers. However, we cannot completely rule out irradiation as a cofactor in the genesis of these cancers, and therefore no longer use irradiation for the conditioning of Fanconi's anaemia patients.