Interstitial pneumonitis after total body irradiation: effect of partial lung shielding

The potential beneficial effects of partial lung shielding were investigated in 44 patients conditioned by whole body radiotherapy as part of the conditioning for bone marrow transplantation (BMT). The first 23 patients were irradiated with fractionated total body irradiation (TBI) to a total dose of 12 Gy. In the second series of 21 patients a 50% transmission lung shield was utilized following 6 Gy TBI. This treatment was combined in the second group with four fractions of 1.5 Gy total lymphoid irradiation (TLI), given in 2 d. The rate of idiopathic interstitial pneumonitis (IP) was 26% in the first group, compared to none in the second.     

Interstitial pneumonitis in T cell-depleted bone marrow transplantation

The incidence of interstitial pneumonitis (IP) was reviewed in 80 consecutive patients who received allogeneic T lymphocyte-depleted bone marrow transplantation (BMT) for malignant and non-malignant diseases. Pretransplant conditioning used in malignant disorders included total lymphoid irradiation (TLI) 150 cGy x 4, total body irradiation (TBI) 200 cGy x 6, and cyclophosphamide (CY) 120 mg/kg. In non-malignant diseases conditioning included no TBI, but adjusted doses of TLI in addition to CY (severe aplastic anemia) or CY and busulfan (severe beta-thalassemia major). In the malignant group only one patient developed graft-versus-host disease (GVHD) grade I; IP developed in 12 out of 61 patients (19.7%) and IP-associated fatality occurred in five patients (8.2%). Cytomegalovirus (CMV) was associated with only two of the five fatal IP. In the non-malignant group there was no GVHD; one patient out of 19 (5.2%) had IP, which was fatal and not associated with CMV. These data indicate that fatal IP may appear in the absence of GVHD. The relatively low incidence of IP-related mortality in recipients of allogeneic T lymphocyte-depleted BMT suggests that although prevention of GVHD and elimination of drugs used for GVHD prevention may reduce the incidence of fatal pulmonary complications, other approaches have to be investigated for complete prevention of IP which still represents a major complication in patients with malignant hematologic disorders treated by allogeneic BMT.     

Fractionated total body irradiation in marrow transplantation for leukaemia

Thirty consecutive patients with leukaemia were prepared for bone marrow transplantation (BMT) with cyclophosphamide (CY) 120 mg/kg followed by total body irradiation (TBI). TBI was delivered in a single dose (sTBI) of 10 Gy, at a dose rate of 0.06-0.08 Gy/min, or in fractionated doses (fTBI) of 3.3 Gy/d, on each of 3 consecutive days, at the same dose rate. Lung shielding was adopted for all patients, in order to obtain a homogeneous dose delivered to the lung and at midline. The first 12 patients were prepared with sTBI and the following 18 with fTBI. Several variables (remission status, mode of irradiation, prevention of graft versus host disease (GvHD) with methotrexate (MTX) or cyclosporin A(CyA) were then analysed for their influence on (a) incidence and mortality of GvHD, (b) incidence and mortality of interstitial pneumonia (IP), (c) 100-d survival, and (d) relapses. Our data suggest that fTBI is the single most important factor associated with a lower incidence of IP (P = 0.002), a lower mortality from GvHD and IP (P = 0.03 and 0.001) and a better 100-d survival (P = 0.03). Remission status had no significant influence on GvHD, IP and acute mortality. When compared to MTX, the use of CyA was associated with less GvHD and IP, but when only patients in remission given fTBI were analysed, this was no longer true. Relapses were mostly influenced by the remission status of the patient at transplant (P = 0.001). Although this is not a randomized study, our data suggest that fTBI can reduce the acute risks of marrow transplantation in leukaemia.     

Development of a marrow transplant regimen for acute leukemia using targeted hematopoietic irradiation delivered by 131I-labeled anti-CD45 antibody, combined with cyclophosphamide and total body irradiation

In an attempt to decrease the relapse rate after bone marrow transplantation (BMT) for advanced acute leukemia, we initiated studies using 131I-labeled anti-CD45 antibody (BC8) to deliver radiation specifically to hematopoietic tissues, followed by a standard transplant preparative regimen. Biodistribution studies were performed in 23 patients using 0.5 mg/kg trace 131I-labeled BC8 antibody. The BC8 antibody was cleared rapidly from plasma with an initial disappearance half-time of 1.5 +/- 0.2 hours, presumably reflecting rapid antigen- specific binding. The mean radiation absorbed doses (cGy/mCi131I administered) were as follows: marrow, 7.1 +/- 0.8; spleen, 10.8 +/- 1.4; liver, 2.7 +/- 0.2; lungs, 2.1 +/- 0.1; kidneys, 0.7 +/- 0.1; and total body, 0.4 +/- 0.03. Patients with acute myelogenous leukemia (AML) in relapse had a higher marrow dose (11.4 cGy/mCi) than those in remission (5.2 cGy/mCi; P = .001) because of higher uptake and longer retention of radionuclide in marrow. Twenty patients were treated with a dose of 131I estimated to deliver 3.5 Gy (level 1) to 7 Gy (level 3) to liver, with marrow doses of 4 to 30 Gy and spleen doses of 7 to 60 Gy, followed by 120 mg/kg cyclophosphamide (CY) and 12 Gy total body irradiation (TBI). Nine of 13 patients with AML or refractory anemia with excess blasts (RAEB) and two of seven with acute lymphocytic leukemia (ALL) are alive disease-free at 8 to 41 months (median, 17 months) after BMT. Toxicity has not been measurably greater than that of CY/TBI alone, and the maximum tolerated dose has not been reached. This study demonstrates that with the use of 131I-BC8 substantially greater doses of radiation can be delivered to hematopoietic tissues as compared with liver, lung, or kidney, which may improve the efficacy of marrow transplantation.     

Induction of donor-type chimerism in murine recipients of bone marrow allografts by different radiation regimens currently used in treatment of leukemia patients

Three radiation protocols currently used in treatment of leukemia patients before bone marrow transplantation (BMT) were investigated in a murine model (C57BL/6----C3H/HeJ) for BM allograft rejection. These include (a) a single dose of total body irradiation (8.5 Gy TBI delivered at a dose rate of 0.2 Gy/min), (b) fractionated TBI (12 Gy administered in six fractions, 2 Gy twice a day in 3 days, delivered at a dose rate of 0.1 Gy/min, and (c) hyperfractionated TBI (14.4 Gy administered in 12 fractions, 1.2 Gy three times a day in 3 days, delivered at a dose rate of 0.1 Gy/min). Donor-type chimerism 6 to 8 weeks after BMT and hematologic reconstitution on day 12 after BMT found in these groups were compared with results obtained in mice conditioned with 8 Gy TBI delivered at a dose rate of 0.67 Gy/min, routinely used in this murine model. The results in both parameters showed a marked advantage for the single dose 8.5 Gy TBI over all the other treatments. This advantage was found to be equivalent to three- to fourfold increment in the BM inoculum when compared with hyperfractionated radiation, which afforded the least favorable conditions for development of donor-type chimerism. The fractionated radiation protocol was equivalent in its efficacy to results obtained in mice irradiated by single-dose 8 Gy TBI, both of which afforded a smaller but not significant advantage over the hyperfractionated protocol. This model was also used to test the effect of radiation dose rate on the development of donor-type chimerism. A significant enhancement was found after an increase in dose rate from 0.1 to 0.7 Gy/min. Further enhancement could be achieved when the dose rate was increased to 1.3 Gy/min, but survival at this high dose rate was reduced. These results demonstrated indirectly that dose rate affects the expression of host-type pluripotent stem cells, the progeny of which appear 3 to 6 weeks after treatment with 8 Gy TBI delivered at a dose rate of 0.1 Gy/min, but which are eradicated if radiation is delivered at a dose rate of 1.3 Gy/min.     

Busulfan and cyclophosphamide as a preparative regimen for bone marrow transplantation in patients with prior chest radiotherapy

In a previous study, we reported that patients with hematologic malignancies who had received prior chest radiotherapy had a 32% risk of developing fatal interstitial pneumonia (IP) when prepared for bone marrow transplantation (BMT) with a regimen containing total body irradiation (TBI). To determine if avoidance of TBI would lessen the incidence of fatal IP, 37 patients who had received prior chest radiotherapy in excess of 2000 cGy were prepared with busulfan (BU, 4 mg/kg x 4 days) and cyclophosphamide (CY, 60 mg/kg x 2 days) followed by autologous (n = 15) or allogeneic (n = 22) BMT. Thirty-five of these patients had recurrent or refractory hematologic malignancies and most were heavily pretreated. Results were compared with the group of similar patients (n = 25) previously treated at our institution with a CY/TBI conditioning regimen. Among those treated with BU/CY, two patients (5%) developed fatal interstitial pneumonia, 12 (32%) died of other transplant related toxicities and 13 (35%) died of relapse. Seven (19%) patients remain alive and well. Among those treated with CY/TBI, eight (32%) died of pneumonia, six (24%) died of relapse, nine (36%) died of other causes and two (8%) remain alive and well. The 5% incidence of fatal interstitial pneumonitis in the chemotherapy conditioned group was significantly less than the 32% incidence in the previously treated CY/TBI group (p = 0.005). However, long-term survival and relapse probabilities were not significantly better than seen previously with CY/TBI, although a trend towards improved survival was observed in the BU/CY group. Avoidance of TBI appeared to lower the incidence of fatal pneumonitis in patients with prior chest radiotherapy.     

Total body irradiation with or without lung shielding for allogeneic bone marrow transplantation.

From June 1986 to June 1990, 64 patients with leukaemia (25 acute myelogenous leukaemia, 21 acute lymphoblastic leukaemia and 18 chronic myeloid leukaemia) undergoing marrow transplantation were randomized to receive cyclophosphamide (CY) and fractionated total body irradiation (TBI) without lung shielding (n = 33) or CY and fractionated TBI with lung shielding (n = 31, control group) as conditioning. Patients conditioned with TBI without lung shielding received a significantly higher total lung dose compared with the control group (p less than 0.0001). The 3-year leukaemia-free survival for patients receiving TBI without lung shielding is 54 +/- 18% versus 51 +/- 18% for patients receiving TBI with lung shielding (p = ns). There was no significant difference in the probability of leukaemia relapse (22 +/- 18% for TBI without lung shielding versus 24 +/- 18% for control group; p = ns). The probability of interstitial pneumonitis is 15 +/- 14% for TBI without lung shielding and 5 +/- 5% for TBI with lung shielding (p = ns). A higher incidence of lung fungal infection (15 versus 3%) and interstitial pneumonitis (12 versus 3%) has been documented in patients receiving TBI without lung shielding compared with the control group. The results indicate that higher radiation dose to the lung did not increase antileukaemic efficacy of TBI but seemed to be associated with the increased pulmonary toxicity.     

Eye shielding during total body irradiation for bone marrow transplantation in children transplanted for a hematological disorder: risks and benefits

This is a retrospective analysis of 188 children who underwent total body irradiation (TBI) in one or two fractions before bone marrow transplantation (BMT) for a hematological disorder. While 139 children had eye shielding during TBI to decrease cataract formation, 49 did not. The blocks used for shielding caused cylindrical areas of decreased dose intensity in the brain. The aim of the study was to determine if there was an increased risk of relapse in the eyes or in the CNS after shielding of the eyes. The probability and severity of cataract formation with and without shielding were also evaluated. None of the 49 children without shielding had a relapse in their eyes or in the CNS after BMT. Of the children with shielding, none had a relapse in the eyes but two of the 139 (1.4%) had a CNS relapse. The incidence of cataracts without shielding was 90% (19 of 21 evaluable patients), while with shielding it was 31% (20 of 64). Severe cataracts were present in eight of 21 (38%) patients without and two of 64 (3%) patients with shielding. The probability of staying cataract free for at least five years was 0.77 with and 0.33 without shielding, at 8 years it was 0.53 and 0.24 respectively. The relative risk of developing a cataract without shielding vs shielding was three (95% CI=1.5; 5.9). It appears that the incidence of relapse in the eyes and CNS is not increased when the eyes are shielded during TBI. Shielding increased the latency time of cataract formation and decreased the severity of cataracts.     

Effect of radiation dose on the development of mixed haemopoietic chimerism following T cell-depleted allogeneic bone marrow transplantation.

The presence of mixed haemopoietic chimerism (MXC) was evaluated by cytogenetic and molecular analysis in 48 patients undergoing T cell-depleted BMT. The dose of total body irradiation (TBI) prescribed to all patients (14.4 Gy) was calculated to compensate for the absence of T cells in the graft. The actual midline dose of TBI received, however, differed significantly depending on the method of TBI administration. Thus, 35 adult patients received an average midline dose of 14.3 Gy, while 13 children received a lower dose of 13 Gy. The incidence of MXC in the adult group, who had received very close to 14.4 Gy to the midline, was 34% (12/35), which is lower than in most reported T cell-depleted series. During follow-up, chimerism remained relatively stable with time but varied between haemopoietic lineages. There was no relationship with relapse. MXC in the 13 children who had received a lower midline TBI dose was significantly higher at 69% (9/13) (p < 0.05) and increased to 90% (9/10) if patients who received additional chemotherapy in their conditioning were excluded (p = 0.001). This suggests that, in terms of marrow ablation, relatively small changes in the dose of TBI may be biologically significant, at least at this dose range. Again, in the lower TBI group MXC was not predictive of relapse.     

The effect of total body irradiation dose and chronic graft-versus-host disease on leukaemic relapse after allogeneic bone marrow transplantation

One-hundred and five patients undergoing allogeneic bone marrow transplantation (BMT) for acute myeloid leukaemia (AML) (n = 61) and chronic myeloid leukaemia (n = 44) were analysed for risk factors associated with relapse. All patients received marrow from an HLA identical sibling after preparation with cyclophosphamide 120 mg/kg and total body irradiation (TBI) 330 cGy on each of the three days prior to transplantation. There was a difference of +/- 18% between the nominal total dose of 990 cGy and the actual dose received as indicated by dosimetric recordings. While interstitial pneumonitis had minimal impact on survival (4%) there was a considerable difference in the incidence of relapses. The incidence of relapse was 55% versus 11% in patients receiving less or more than 990 cGy respectively and this had a major impact on survival (38% v. 74% at 7 years) since transplant-related mortality was comparable in the two groups. A multivariate Cox analysis indicated that a lower TBI dose (less than 990 cGy) was the most significant factor associated with relapse and the second most important factor associated with recurrence of leukaemia was the absence of chronic graft-versus-host-disease (cGvHD). Actuarial relapse incidence was 62%. 28% and 18% for patients with no, limited or extensive chronic GvHD respectively. However, chronic GVHD had no significant impact on survival. Combined stratification for TBI dose and cGvHD showed that the dose effect of TBI on relapse was evident both in patients with and without cGvHD. Chronic GvHD influenced the risk of relapse only in patients receiving less than 990 cGy. These results suggest that a higher dose of TBI, within this schedule, produced long-term disease-free survival in the majority of AMLs and CMLs. Minor radiobiological side effects were experienced but a small reduction of the dose may significantly increase the risk of relapse.     

Influence of the conditioning regimen on erythrocyte chimerism, graft-versus-host disease and relapse after allogeneic transplantation with lymphocyte depleted marrow.

Three different conditioning regimens were applied to 144 patients undergoing allogeneic bone marrow transplantation (BMT) with HLA identical sibling marrow, depleted of lymphocytes by counterflow centrifugation. All regimens consisted of cyclophosphamide and fractionated total body irradiation (TBI). In 49 patients treated with regimen A the total TBI dose was 9 Gy. In regimen B the dose rate of TBI was increased and anthracyclines were added (n = 65). Thirty patients received regimen C with a total TBI dose of 12 Gy but no anthracyclines. The different conditioning regimens did not influence the percentage of patients with detectable recipient CFU-GM prior to infusion of donor marrow. The incidences of mixed erythrocyte chimerism at 6 months after BMT were 73, 33 and 20% for regimens A, B and C respectively. The conditioning regimen influenced significantly mixed erythrocyte chimerism from 6 to 24 months after BMT. Both age and the conditioning regimen influenced significantly the incidence of acute graft-versus-host disease (GVHD) (p = 0.017 and 0.0001 respectively). Acute GVHD greater than or equal to I occurred in 15, 29 and 77% of the patients treated with regimens A, B and C respectively. The incidence of acute and chronic GVHD was significantly higher in complete donor chimeras than in mixed chimeras (p less than 0.001 and p less than 0.01). The probability of relapse was 43% in 32 and 18% in 43 good risk patients treated with regimens A and B respectively (p = 0.07). Longer follow-up is needed to draw conclusions about relapse in regimen C.(ABSTRACT TRUNCATED AT 250 WORDS)     

The development of cataract in children as a late side-effect of bone marrow transplantation

Children with hematological malignancies (n = 33), severe aplastic anemia (SAA, n = 7) and other non-malignant diseases (n = 4) were followed for cataract development after bone marrow transplantation (BMT). The children with hematological malignancies were subjected to total body irradiation (TBI), 10 Gy, in one session with no shielding of the eyes as part of their conditioning regimen before BMT. The children with SAA or other non-malignant diseases received either no irradiation before BMT or a reduced dose, 8 Gy, with shielding of their eyes. After 3 years all patients who had undergone BMT for hematological malignancies had developed lens opacification. No patients in the other groups, without leukemia, showed any sign of cataract development. There was no relationship between steroid treatment for graft-versus-host disease and cataract development. No relation to age of onset of treatment or to the sex of the patient and cataract formation was seen. It seems evident from the present study that TBI given in one session was the main cause of cataract development after BMT.     

Pulmonary function following total body irradiation (with or without lung shielding) and allogeneic peripheral blood stem cell transplant

Our purpose was to determine if total body irradiation (TBI) with lung dose reduction protects against subsequent radiation-induced deterioration in pulmonary function. Between July 1997 and August 2004, 181 consecutive patients with hematologic malignancies received fractionated TBI before allogeneic peripheral blood stem cell transplant. The first 89 patients were treated to a total dose of 13.6 Gy. Thereafter, total body dose was decreased to 12 Gy with lung dose reduction to 9 or 6 Gy. All patients underwent pulmonary function test evaluation before treatment, 90 days post-treatment, then annually. Median follow-up was 24.0 months. Eighty-nine patients were treated with lung shielding, and 92 without. At 1-year post transplant, there was a small but significant difference in lung volume measurements between patients with lung shielding and those without. This was not observed at the 2-year time point. When stratified by good (>100% predicted) or poor (相似文献   

Marrow transplantation for acute nonlymphoblastic leukemia in first remission: toxicity and long-term follow-up of patients conditioned with single dose or fractionated total body irradiation

Seventy-five patients with acute nonlymphoblastic leukemia (ANL) in first remission were treated with cyclophosphamide, 60 mg/kg on each of two consecutive days followed by total body irradiation (TBI) at an exposure rate of 4-6 cGy/min from two opposing 60Co sources. The first 22 patients were given 9.2 Gy of TBI as a single dose. Subsequently 53 patients were randomized to receive either 10 Gy single dose TBI (n = 27) or 6 x 2 Gy fractionated TBI (n = 26). All patients received marrow transplants from HLA-identical siblings and all had sustained engraftment. Patients given 10 Gy of TBI had more early toxicity, especially veno-occlusive disease of the liver, than patients given 9.2 or 6 x 2 Gy of TBI. Idiopathic interstitial pneumonitis appeared to be more frequent in patients given 9.2 or 10 Gy single-dose TBI than in patients given 6 x 2 Gy fractionated TBI. Patients have now been followed from 5 to 9 years. Survival (+/- 95% confidence limits) at 5 years is 54 +/- 31% among patients given 9.2 Gy single dose TBI, 33 +/- 31% among patients given 10 Gy single dose TBI, and 54 +/- 26% among patients given 6 x 2 Gy fractionated TBI (P = 0.04). These results indicate that about half the patients with ANL transplanted while in first chemotherapy-induced remission can be expected to become long-term survivors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Changes in height, weight and plasma leptin after bone marrow transplantation

Short stature can be a severe side-effect of bone marrow transplantation (BMT). Because of the effect of weight changes on growth rate and on plasma insulin-like growth factor (IGF I), we analyzed changes in height and body mass index (BMI) in 53 patients given BMT. Group 1 (n = 22) was given 12 Gy total body irradiation (TBI) as six fractions, group 2 (n = 14) 10 Gy TBI (one dose), group 3 (n = 8) 6 Gy total lymphoid irradiation (one dose), and group 4 (n = 9) chemotherapy alone. At the first evaluation, 13/36 patients in groups 1 and 2 had low growth hormone (GH) peaks after stimulation. The mean plasma IGF I concentrations (z score) were similar in groups 1 (-2.9 +/- 0.3) and 2 (-2.5 +/- 0.3), and in groups 3 (-1.4 +/- 0.3) and 4 (-1.4 +/- 0.7), but those of group 1 were lower than those of groups 3 (P < 0.01) and 4 (P < 0.05), and those of group 2 than those of group 3 (P < 0.05). BMI during the 5 years after BMT did not change in groups 1 and 2, decreased in group 3, and increased in group 4. However, these changes were not significant. Most of the patients given TBI had BMI below the mean at 2 (66%) and 5 (57%) years later. Their BMI and leptin concentrations correlated positively with each other (P = 0.005), and negatively with GH peak (P = 0.02 for BMI and 0.007 for leptin). In conclusion, this study suggests that TBI actually decreases GH secretion and is followed by a persistent low BMI. The negative relationship between GH peak and leptin may indicate that both are markers of a TBI-induced hypothalamic-pituitary lesion.     

Fractionated versus single-dose total body irradiation at low and high dose rates to condition canine littermates for DLA-identical marrow grafts

We explored in dogs the immunosuppressive properties of 450 cGy total body irradiation (TBI) delivered from two opposing 60Co sources, as assessed by the criterion of successful engraftment of allogeneic genotypically DLA-identical littermate marrow. Two questions were asked in this study. Firstly, does dose rate affect the immunosuppressive effect of TBI when administered in a single dose? Secondly, does fractionation alter the immunosuppression of TBI when delivered at a very fast dose rate? Dose rates studied included 7 and 70 cGy/min, and fractionation involved four fractions of 112.5 cGy each, with 6-hour minimum interfraction intervals. Six of 7 dogs receiving 450 cGy single- dose TBI at 70 cGy/min showed sustained engraftment of the allogeneic marrow, compared with 1 of 7 dogs receiving single-dose TBI at 7 cGy/min (P = .01). Fractionated TBI at 70 cGy/min resulted in sustained allogeneic engraftment in 3 of 10 dogs, a result that was statistically significantly worse than that with single-dose TBI at 70 cGy/min (P = .03) and not statistically different (P = .24) from that with fractionated TBI delivered at 7 cGy/min (0 of 5 dogs engrafted). A single dose of 450 cGy of TBI delivered at a rate of 70 cGy/min is significantly more immunosuppressive than the same total dose delivered at 7 cGy/min. Fractionated TBI at 70 cGy/min is significantly less immunosuppressive than single-dose TBI at 70 cGy/min and not significantly different from fractionated TBI administered at 7 cGy/min. Results are consistent with the notion that significant DNA repair in lymphoid cells is possible during interfraction intervals at the relatively high dose rate of 70 cGy/min.     

Successful pregnancy after total body irradiation and bone marrow transplantation for acute leukaemia.

We report successful pregnancies in two young women (aged 24 and 20 years) following allogeneic bone marrow transplantation (BMT) for acute non-lymphoblastic leukaemia. Conditioning therapy consisted of cyclophosphamide (120 mg/kg) and total body irradiation (TBI, 12 Gy) in 2 Gy fractions once daily for 6 days or twice daily for 3 days. Graft-versus-host disease prophylaxis was with methotrexate alone. Both women were amenorrhoeic after BMT and gonadal testing indicated hypergonadotrophic hypogonadism. Both women had normal pregnancies (2 years and 5 years after BMT) resulting in normal healthy infants. Previously successful pregnancy has been reported after TBI in three women in whom the TBI dose was less than 8 Gy. Our cases illustrate that normal outcome of pregnancy is possible at even higher doses of TBI.     

Allogeneic marrow transplantation in patients with acute myeloid leukemia in first remission: a randomized trial of two irradiation regimens

A randomized trial of 12.0 Gy versus 15.75 Gy of total body irradiation (TBI) was performed in patients with acute myeloid leukemia undergoing allogeneic marrow transplantation while in first complete remission. All patients received 120 mg/kg cyclophosphamide followed by TBI and marrow from HLA-identical siblings. Cyclosporine and methotrexate were used for prophylaxis against acute graft-versus-host disease (GVHD). Thirty-four patients received 2.0-Gy fractions of irradiation daily for 6 days and 37 received 2.25-Gy fractions daily for 7 days. The 3-year actuarial probabilities for relapse-free survival were 0.58 for the patients who received 12.0 Gy and 0.59 for those who received 15.75 Gy. The 3-year probabilities of relapse were 0.35 for the 12.0 Gy group and 0.12 for the 15.75 Gy group (P = .06). The 3-year probabilities of transplant-related mortality were 0.12 and 0.32, respectively (P = .04). The probability of moderate to severe acute GVHD was 0.21 for the 12.0 Gy group and 0.48 for the 15.75 Gy group (P = .02). Patients exposed to the higher irradiation dose received less immunoprophylaxis against, and had a higher incidence of, acute GVHD. The increased dose of TBI significantly reduced the probability of relapse but did not improve survival because of increased mortality from causes other than relapse.     

Secondary thyroid carcinoma after allogeneic bone marrow transplantation during childhood.

The aim of this study was to evaluate the incidence and risk factors related to secondary thyroid carcinoma (STC) in patients who have undergone allogeneic BMT during childhood. Data related to the primary hematological disorder and BMT procedure were obtained from the records of 113 patients (42 F; 71 M) who underwent BMT before the age of 18 (median 10.0 years; range 1.7-18.0) and survived more than 3 years after transplant with a median follow-up of 10.1 years (range 3.0-19.0). Sixteen received cranial radiation (CRT) during first-line treatment. Pre-transplant conditioning included TBI in 85 patients, TAI in two, while 26 children did not receive irradiation. The standardized incidence ratio of STC after BMT was significantly higher (P < 0.001) than that of the general population. STC was found in eight patients, 3.1 to 15.7 years after transplant. All received TBI and three also CRT. The Cox's regression analysis, although not statistically significant due to the small study population, showed an increased risk in those who had received a cumulative radiation dose higher than 10 Gy and in those who developed chronic GVHD. Careful follow-up of thyroid status including annual ultrasound examination is recommended for early detection of tumor.