Effect of microdistribution of alpha and beta-emitters in targeted radionuclide therapies on delivered absorbed dose in a GATE model of bone marrow.

Acute hematologic toxicity is a frequent adverse effect of beta-emitter targeted radionuclide therapies (TRTs). Alpha emitters have the potential of delivering high linear energy transfer (LET) radiation to the tumor attributed to its shorter range. Antibody-based TRTs have increased blood-pool half-lives, and therefore increased marrow toxicity, which is a particular concern with alpha emitters. Accurate 3D absorbed dose calculations focusing on the interface region of blood vessels and bone can elucidate energy deposition patterns. Firstly, a cylindrical geometry model with a central blood vessel embedded in the trabecular tissue was modeled. Monte Carlo simulations in GATE were performed considering beta (177Lu, 90Y) and alpha emitters (211At, 225Ac) as sources restricted to the blood pool. Subsequently, the radioactive sources were added in the trabecular bone compartment in order to model bone marrow metastases infiltration (BMMI). Radial profiles, dose-volume histograms and voxel relative differences were used to evaluate the absorbed dose results. We demonstrated that alpha emitters have a higher localized energy deposition compared to beta emitters. In the cylindrical geometry model, when the sources are confined to the blood pool, the dose to the trabecular bone is greater for beta emitting radionuclides, as alpha emitters deposit the majority of their energy within 70 µm of the vessel wall. In the BMMI model, alpha emitters have a lower dose to untargeted trabecular bone. Our results suggest that when alpha emitters are restricted to the blood pool, as when labeled to antibodies, hematologic toxicities may be lower than expected due to differences in the microdistribution of delivered absorbed dose.

Prolonged response to 177Lu-DOTATATE therapy of a bone marrow infiltration in a refractory thymic neuro endocrine tumor.

Thymic neuro endocrine tumor (tNET) are extremely rare malignancies with poor prognosis, requiring investigation of novel therapeutic approaches. 177Lu-DOTATATE is a successful systemic treatment modality in patients with metastatic gastroenteropancreatic but it role in tNET is not yet well established. Here we report a case of a 39-year-old man with refractory bone marrow infiltration of a tNET, treated by 4 cycles of peptide receptor radionuclide therapy (PRRT) with 177Lu DOTATATE. Since the first cycle, clinical symptoms were substantially decreased, without any severe subacute haematological toxicity. Three months after the end of PRRT, both 68Ga-DOTATOC and 18F-FDG PET confirmed a partial response, already suggested by 177Lu-DOTATATE treatment scan with a significant decrease of the bone marrow uptake between the first and fourth cycle. This report highlights that PRRT could be an effective therapeutic option for advanced bone metastatic disease tNET, with the significant benefit of alleviation of bone pain and radiologic response, without severe or irreversible haematotoxicity.

[Clinical characteristics and prognosis of high-risk neuroblastoma with bone marrow metastasis in children].

Objective: To analyze the clinical characteristics of newly treated high-risk group neuroblastoma (NB) patients with bone marrow metastasis and to explore the prognostic factors. Methods: The clinical features (sex, age, stage, risk group, pathological type, metastatic site, etc.) of 203 newly treated high-risk NB patients with bone marrow metastasis admitted to Hematology Oncology Center, Beijing Children's Hospital from January 2007 to December 2016 were analyzed retrospectively. There were 118 males (58.1%) and 85 females (41.9%). Kaplan-Meier method was used for survival analysis and Cox regression was used to analyze the prognostic factors. Results: The age at onset of the 203 patients was 41 months (9-147 months). The metastatic sites at diagnosis were as follows: bone in 195 cases (96.1%), distant lymph nodes in 104 cases (51.2%), skull and endomeninx in 61 cases (30.0%), orbit in 30 cases (14.8%), pleura in 16 cases (7.9%), liver in 13 cases(6.4%), canalis spinalis in 13 cases (6.4%), other sites in 11 cases (5.4%) and skin and soft tissue in 10 cases (4.9%). In all, 194 cases were enrolled for prognostic analysis. The follow-up time was 36 months (1 day-138 months) , and the 5-years event free survival (EFS) and overall survival (OS) were 36.1% and 39.7%, respectively. A total of 118 patients (60.8%) had events (first relapse or death) with the time to event occurrence was 15 months (1 day-72 months), whereas 112 patients (57.7%) died with the event occurrence to death time was 3 months (1 day-21 months). There was no significant difference in 5-years OS between radiotherapy group and non-radiotherapy group (42.3% vs. 38.3%, χ(2)=3.671, P=0.055). The 5-years OS in transplantation group was significantly better than the non-transplantation group (44.3% vs. 35.5%, χ(2)=8.878, P=0.003), and the radiotherapy combined transplantation group also had a better 5-years OS rate than the non-radiotherapy combined transplantation group (45.8% vs. 37.3%, χ(2)=5.945, P=0.015). Univariate survival analysis showed lactate dehydrogenase ≥ 1 500 U/L, the amplification of MYCN, the metastatic sites of orbit, canalis spinalis and pleura were associated with poor prognosis of newly diagnosed high-risk NB patients (χ(2)=21.064, 13.601, 3.998, 6.183, 15.307, all P<0.05). The amplification of MYCN and the metastatic sites of pleura were risk factors for prognosis of newly diagnosed high-risk NB patients by Cox regression models (HR=1.896,1.100, 95%CI: 1.113-3.231, 1.020-1.187, both P<0.05). Conclusions: The prognosis is unfavorable in high-risk group NB patients with BM metastasis. Radiotherapy combined with transplantation can further improve the prognosis of these patients. The amplification of MYCN and the metastatic sites of pleura were the poor prognostic factors for high-risk NB patients with bone marrow metastasis.

Neuroblastoma of the Bone and Bone Marrow Without an Apparent Primary Site: Report of 4 Cases With Long-term Follow-up.

Children with neuroblastoma rarely present with metastatic disease without identifiable primary tumors. We describe the clinical and histopathologic characteristics of 4 patients aged 1, 7, 7, and 11 years with neuroblastoma involving bone or bone marrow without an apparent primary site. One patient presented with a periorbital bone lesion, 1 presented with a distal femoral lesion, and 2 presented with diffuse bone marrow involvement. All tumors were negative for MYCN amplification. All patients were alive without evidence of disease 5 years after completion of multimodality therapy. Patients with neuroblastoma of the bone and bone marrow without an apparent primary site may constitute a unique group characterized by older age at diagnosis, nonamplified MYCN tumors, and good response to treatment.

Fast, simple, and informative patient-specific dose verification method for intensity modulated total marrow irradiation with helical tomotherapy.

BACKGROUND: Patient-specific dose verification for treatment planning in helical tomotherapy is routinely performed using a homogeneous virtual water cylindrical phantom of 30 cm diameter and 18 cm length (Cheese phantom). Because of this small length, treatment with total marrow irradiation (TMI) requires multiple deliveries of the dose verification procedures to cover a wide range of the target volumes, which significantly prolongs the dose verification process. We propose a fast, simple, and informative patient-specific dose verification method which reduce dose verification time for TMI with helical tomotherapy. METHODS: We constructed a two-step solid water slab phantom (length 110 cm, height 8 cm, and two-step width of 30 cm and 15 cm), termed the Whole Body Phantom (WB phantom). Three ionization chambers and three EDR-2 films can be inserted to cover extended field TMI treatment delivery. Three TMI treatment plans were conducted with a TomoTherapy HiArt Planning Station and verified using the WB phantom with ion chambers and films. Three regions simulating the head and neck, thorax, and pelvis were covered in a single treatment delivery. The results were compared to those with the cheese phantom supplied by Accuray, Inc. following three treatment deliveries to cover the body from head to pelvis. RESULTS: Use of the WB phantom provided point doses or dose distributions from head and neck to femur in a single treatment delivery of TMI. Patient-specific dose verification with the WB phantom was 62% faster than with the cheese phantom. The average pass rate in gamma analysis with the criteria of a 3-mm distance-to-agreement and 3% dose differences was 94% ± 2% for the three TMI treatment plans. The differences in pass rates between the WB and cheese phantoms at the upper thorax to abdomen regions were within 2%. The calculated dose agreed with the measured dose within 3% for all points in all five cases in both the WB and cheese phantoms. CONCLUSIONS: Our dose verification method with the WB phantom provides simple and rapid quality assurance without limiting dose verification information in total marrow irradiation with helical tomotherapy.

Radiotherapy in metastatic ewing sarcoma.

OBJECTIVE: To review an institutional experience with radiotherapy (RT) in patients with metastatic Ewing sarcoma. METHODS: Thirty patients with metastatic Ewing sarcoma were considered. Twenty-nine received multiagent chemotherapy, whereas 22 had local therapy, which included RT in 14, surgery in 5, and surgery followed by RT in 3. RESULTS: The 5-year overall survival rate was 22.1%. On multivariate analysis, presence of uncommon sites of metastasis (brain, liver, spleen) (P<0.0001) and use of local therapy to the primary site (P<0.001) were adverse factors for survival. Local control was not achieved in the 8 patients receiving only chemotherapy. All long-term survivors had local therapy including RT to metastatic bony sites and whole-lung irradiation for pulmonary metastasis. CONCLUSIONS: The presence of uncommon sites of metastasis confers a worse prognosis. Aggressive primary treatment including RT to metastatic sites should be considered in these patients.

Tumor lysis syndrome during radiotherapy for prostate cancer with bone and bone marrow metastases without visceral metastasis.

A 60-year-old male patient presented to our clinic with metastatic (bone and bone marrow) prostate cancer. Radiotherapy (RT) with a total of 30 Gy was planned in 10 fractions for the painful left shoulder region. On the 6th day of RT, urinary output decreased suddenly and dyspnea developed. Laboratory findings suggested tumor lysis syndrome (TLS). The patient, who showed improvement in overall status and had no requirement for hemodialysis up to this time, developed sudden impairment in overall status, dyspnea, and hypotension on the 11th day of follow-up. Thirty minutes after the development of these symptoms, the patient had a cardiopulmonary arrest and died. At the time of writing this was the fourth case of TLS during RT for solid tumors in adults, the first case of TLS during RT for prostate cancer and the fifth among total cases of prostate cancer in published reports.

Anatomy driven optimization strategy for total marrow irradiation with a volumetric modulated arc therapy technique.

The purpose of this study was to evaluate the possibility of dose distribution optimization for total marrow irradiation (TMI) employing volumetric-modulated arc therapy (VMAT) with RapidArc (RA) technology setting isocenter's positions and jaw's apertures according to patient's anatomical features. Plans for five patients were generated with the RA engine (PROIII): eight arcs were distributed along four isocenters and simultaneously optimized with collimator set to 90°. Two models were investigated for geometrical settings of arcs: (1) in the "symmetric" model, isocenters were equispaced and field apertures were set the same for all arcs to uniformly cover the entire target length; (2) in the "anatomy driven" model, both field sizes and isocenter positions were optimized in order to minimize the target volume near the field edges (i.e., to maximize the freedom of motion of MLC leaves inside the field aperture (for example, avoiding arcs with ribs and iliac wings in the same BEV)). All body bones from the cranium to mid of the femurs were defined as PTV; the maximum length achieved in this study was 130 cm. Twelve (12) Gy in 2 Gy/fractions were prescribed in order to obtain the covering of 85% of the PTV by 100% of the prescribed dose. For all organs at risk (including brain, optical structures, oral and neck structures, lungs, heart, liver, kidneys, spleen, bowels, bladder, rectum, genitals), planning strategy aimed to maximize sparing according to ALARA principles, looking to reach a mean dose lower than 6 Gy (i.e., 50% of the prescribed dose). Mean MU/fraction resulted 3184 ± 354 and 2939 ± 264 for the two strategies, corresponding to a reduction of 7% (range -2% to 13%) for (1) and (2). Target homogeneity, defined as D(2%)-D(98%) was 18% better for (2). Mean dose to the healthy tissue, defined as body minus PTV, had 10% better reduction with (2). The isocenter's position and the jaw's apertures are significant parameters in the optimization of the TMI with RA technique, giving the medical physicist a crucial role in driving the optimization and thus obtaining the best plan. A clinical protocol started in our department in October 2010.

Central nervous system Hodgkin lymphoma: case report and review of the literature.

Central nervous system (CNS) involvement by Hodgkin lymphoma (HL) is extremely rare, accounting for 0.5% or less of HL cases. In contrast, CNS involvement can occur in 5-30% of patients with non-Hodgkin lymphoma. CNS HL can present at any point in the course of HL, most commonly during relapsing disease, and has been described in both immunocompromised and immunocompetent patients. We describe a case of HL affecting the CNS and bone marrow on initial presentation in a 79-year-old immunocompetent female with a prior history of squamous cell carcinoma of the larynx and adenocarcinoma of the lung. Following the case report, a review of the literature on CNS HL is presented.

Modified total body irradiation as a planned second high-dose therapy with stem cell infusion for patients with bone-based malignancies.

PURPOSE: To estimate the maximum tolerated dose of hyperfractionated total marrow irradiation (TMI) as a second consolidation after high-dose chemotherapy with autologous or syngeneic blood stem cell transfusion for patients with bone/bone marrow-based malignant disease. PATIENTS AND METHODS: Fifty-seven patients aged 3-65 years (median, 45 years), including 21 with multiple myeloma, 24 with breast cancer, 10 with sarcoma, and 2 with lymphoma, were treated with 1.5 Gy administered twice daily to a total dose of 12 Gy (n = 27), 13.5 Gy (n = 12), and 15 Gy (n = 18). Median time between the 2 transplants was 105 days (range, 63-162 days). RESULTS: All patients engrafted neutrophils (median, Day 11; range, Day 9-23) and became platelet independent (median, Day 9; range, Day 7-36). There were 5 cases of Grade 3-4 regimen-related pulmonary toxicity, 1 at 12 Gy, and 4 at 15 Gy. Complete responses, partial responses, and stabilizations were achieved in 33%, 26%, and 41% of patients, respectively. Kaplan-Meier estimates of 5-year progression-free survival and overall survival for 56 evaluable patients are 24% and 36%, respectively. Median time of follow-up among survivors was 96 months (range, 77-136 months). CONCLUSION: Total marrow irradiation as a second myeloablative therapy is feasible. The estimated maximum tolerated dose for TMI in a tandem transplant setting was 13.5 Gy. Because 20% of patients are surviving at 8 years free of disease, further studies of TMI are warranted.

Feasibility study of helical tomotherapy for total body or total marrow irradiation.

Total body radiation (TBI) has been used for many years as a preconditioning agent before bone marrow transplantation. Many side effects still plague its use. We investigated the planning and delivery of total body irradiation (TBI) and selective total marrow irradiation (TMI) and a reduced radiation dose to sensitive structures using image-guided helical tomotherapy. To assess the feasibility of using helical tomotherapy, (A) we studied variations in pitch, field width, and modulation factor on total body and total marrow helical tomotherapy treatments. We varied these parameters to provide a uniform dose along with a treatment times similar to conventional TBI (15-30 min). (B) We also investigated limited (head, chest, and pelvis) megavoltage CT (MVCT) scanning for the dimensional pretreatment setup verification rather than total body MVCT scanning to shorten the overall treatment time per treatment fraction. (C) We placed thermoluminescent detectors (TLDs) inside a Rando phantom to measure the dose at seven anatomical sites, including the lungs. A simulated TBI treatment showed homogeneous dose coverage (+/-10%) to the whole body. Doses to the sensitive organs were reduced by 35%-70% of the target dose. TLD measurements on Rando showed an accurate dose delivery (+/-7%) to the target and critical organs. In the TMI study, the dose was delivered conformally to the bone marrow only. The TBI and TMI treatment delivery time was reduced (by 50%) by increasing the field width from 2.5 to 5.0 cm in the inferior-superior direction. A limited MVCT reduced the target localization time 60% compared to whole body MVCT. MVCT image-guided helical tomotherapy offers a novel method to deliver a precise, homogeneous radiation dose to the whole body target while reducing the dose significantly to all critical organs. A judicious selection of pitch, modulation factor, and field size is required to produce a homogeneous dose distribution along with an acceptable treatment time. In addition, conformal radiation to the bone marrow appears feasible in an external radiation treatment using image-guided helical tomotherapy.

Preparation of (166)Dy/(166)Ho-EDTMP: a potential in vivo generator system for bone marrow ablation.

BACKGROUND AND AIM: Bone-seeking radiopharmaceuticals have been proposed for delivering ablative radiation doses to marrow in multiple myeloma and other haematological malignancies. The aim of this research was to examine the feasibility of labelling ethylenediaminetetramethylenephosphonate (EDTMP) with Dy/Ho as an in vivo generator system and to evaluate whether the in vitro and in vivo stability of Dy-EDTMP and Ho-EDTMP complexes is maintained when the daughter Ho is formed. METHODS: Dy was obtained by neutron irradiation of enriched Dy2O3 in a TRIGA Mark III reactor. Labelling was carried out in an aqueous phosphate medium at pH 8.0 by addition of DyCl3 to EDTMP at a molar ratio 1:1.75. Dy/Ho labelled EDTMP was obtained with a 99.3+/-0.6% radiochemical purity determined by thin-layer chromatography and high-performance liquid chromatography. RESULTS: In vitro studies demonstrated that Dy/Ho-EDTMP is unstable after dilution in saline and stable in human serum and no translocation of the daughter nucleus occurring subsequent to beta decay of Dy which could produce release of Ho. Biodistribution in mice shows a fast blood clearance after administration of Dy/Ho-EDTMP with a skeletal uptake of 22.32+/-1.86% ID/g at 2 h and 20.12+/-1.94% ID/g after 10 d, a rapid renal elimination and no accumulation in other organs. Theoretical bone marrow absorbed dose calculations indicate that the Dy/Ho-EDTMP in vivo generator system would produce 7.80 times more radiation dose to marrow than that produced by Sm-EDTMP and 3.47 times more than Ho-DOTMP per unit of initial activity retained in the skeleton. CONCLUSION: The prepared radiolabelled EDTMP has adequate properties as a stable in vivo generator system for bone marrow ablation.

Nasal NK/T-cell lymphoma with disseminated disease treated with aggressive combined therapy.

Thirty-two patients with nasal NK/T-cell lymphoma and disseminated disease (lung, skin, and bone marrow) were treated with an intensive combined therapy that consisted of three cycles of CMED (cyclophosphamide 2 g/m(2), metothrexate 200 mg/m(2), etoposide 600 mg/m(2), and dexamethasone 80 mg/m(2) with leucovorin rescue administered 24 h after) every 14 d, following high-dose radiotherapy: 55 Gy in 20 sesions to centrofacial region and three cycles more of the same chemotherapy regimen. To ameliorate the presence of severe granulocytopenia, granulocyte colony-stimulating factor, 5 microg/kg, daily for 14 d, begun on d 2 after chemotherapy, was administered. Complete response was achieved in 21 cases (65%); failure or progression was observed in 11 cases (35%). With a median follow-up of 69.1 mo, relapse has not been observed; thus, actuarial curves at 5 yr showed that event-free survival (EFS) is 100% in 21 patients and overall survival (OS) is 65%. Granulocytopenia grade IV was observed in 15% cycles, Nonhematological toxicity was mild and well tolerated. Radiotherapy was well tolerated; only mild mucositis was observed. Nasal NK/T-cell lymphoma is an rare presentation of malignant lymphoma (<1% of all cases) with a worse prognosis; less than 5% patients are alive free of disease at 1 yr. The use of intensive more specific chemotherapy and high dose of local radiotherapy, appear to be an excellent therapeutic approach with improvement in EFS and OS.

How effective is dose-intensive/myeloablative therapy against Ewing's sarcoma/primitive neuroectodermal tumor metastatic to bone or bone marrow? The Memorial Sloan-Kettering experience and a literature review.

PURPOSE: Attempts to improve outcomes of patients with Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) metastatic to bone/bone marrow (BM) have focused on chemotherapy dose intensification strategies. We now present results achieved with that approach, as carried out at Memorial Sloan-Kettering Cancer Center (MSKCC) and as reported in the literature. PATIENTS AND METHODS: Twenty-one unselected MSKCC patients with newly diagnosed ES/PNET metastatic to bone/BM received the "P6" protocol which includes cycles of cyclophosphamide (4.2 g/m(2))/doxorubicin (75 mg/m(2))/vincristine and cycles of ifosfamide (9 g/m(2))/etoposide (500 mg/m(2)). Patients in complete/very good partial remission (CR/VGPR) after P6 received myeloablative therapy with either total-body irradiation (TBI) (hyperfractionated 15 Gy)/melphalan (180 mg/m(2)) or thiotepa (900 mg/m(2))/carboplatin (1,500 mg/m(2)). We reviewed the literature. RESULTS: Only one MSKCC patient became a long-term event-free survivor; all but one relapse was in a distant site. Initial responses to P6 were CR/VGPR in 19 patients, but eight of them plus two others developed PD while receiving or shortly after completing P6. Eight patients were treated with TBI/melphalan: four relapsed 2 to 7 months after transplantation; two died early of toxicity; one died of pulmonary failure 17 months after transplantation (no evidence of ES/PNET); and one remains in CR at more than 7 years. The three patients treated with thiotepa/carboplatin relapsed 3 to 4 months after transplantation. All reports on large series of unselected patients with ES/PNET metastatic to bone/BM showed similarly unsatisfactory results. Poor outcome was seen with use of active agents for ES/PNET-cyclophosphamide, ifosfamide, doxorubicin, dactinomycin, vincristine, etoposide - at standard dosages for prolonged periods of time and at higher dosages in intensive regimens for short or prolonged periods of time. No improvements in event-free survival rates occurred with successive cooperative group or large single-institutional studies that used increasingly aggressive chemotherapeutic approaches. Inclusion of ifosfamide with or without etoposide made no difference nor did consolidation of remission with myeloablative chemoradiotherapy. Secondary leukemia emerged as a major risk with dose-intensive regimens. CONCLUSION: The MSKCC experience and findings reported in the literature suggest that dose-intensive use of the chemotherapy agents with established activity against ES/PNET is reaching its efficacy and toxicity limits. A major impact on prognosis awaits the development of entirely novel therapies.

Multifocal primary lymphoma of bone: scintigraphy and MR findings before and after treatment.

A case of multifocal primary lymphoma of bone is reviewed. Ga-67 citrate, Tc-99m HMDP, and Tl-201 scintigraphs all showed multifocal radiotracer accumulation. CT showed subtle osteolytic and osteosclerotic changes with surrounding soft tissue density mass. MRI clearly showed abnormal signal intensity in the bone marrow. After systemic chemotherapy and infield radiotherapy, the patient showed clinically complete remission. MRI showed reduction of the extraosseous components, but there was little signal change in the bone marrow despite the clinical response to the therapy. Scintigrams were more useful than MRI and CT for both staging and assessing the early response to therapy. The soluble interleukin-2 receptor level was found to be related to tumor cell activity.

Radiotherapy and high-dose chemotherapy in advanced Ewing's tumors.

BACKGROUND: Ewing's tumors are sensitive to radio- and chemotherapy. Patients with multifocal disease suffer a poor prognosis. Patients presenting primary bone marrow involvement or bone metastases at diagnosis herald a 3-year disease-free survival below 15%. The European Intergroup Cooperative Ewing's Sarcoma Study (EICESS) has established the following indications for high-dose therapy in advanced Ewing's tumors: Patients with primary multifocal bone disease, patients with early (< 2 years after diagnosis) or multifocal relapse. PATIENTS AND METHOD: As of 1987, 83 patients have been treated in the EICESS group, 39 of them at the transplant center in Düsseldorf, who have been analyzed here. All individuals received 4 courses of induction chemotherapy with EVAJA and stem cell collection after course 3 and 4. Consolidation radiotherapy of the involved bone compartments was administered in a hyperfractionated regimen 2 times 1.6 Gy per day, up to 22.4 Gy simultaneously to course 5 and 22.4 Gy to course 6 of chemotherapy. The myeloablative chemotherapy consisted of melphalan and etoposide (ME) in combination with 12 Gy TBI (Hyper-ME) or Double-ME with whole lung irradiation up to 18 Gy (without TBI). RESULTS: The survival probability at 40 months was 31% (44% DOD; 15% DOC). Pelvic infiltration did not reach prognostic relevance in this cohort. Radiotherapy encompassed 75% of the bone marrow at maximum (average 20%). Engraftment was not affected by radiotherapy. CONCLUSION: High-dose chemotherapy can improve outcome in poor prognostic advanced Ewing's tumors. The disease itself remains the main problem. The expected engraftment problems after intensive radiotherapy in large volumes of bone marrow can be overcome by stem cell reinfusion.

Radiation therapy for consolidation of metastatic or recurrent sarcomas in children treated with intensive chemotherapy and stem cell rescue. A feasibility study.

PURPOSE: To assess the role of consolidative radiation therapy (CRT) in conjunction with myeloablative therapy with or without total body irradiation (TBI) in children and young adults with metastatic or recurrent sarcoma. METHODS AND MATERIALS: Twenty-one pediatric sarcoma patients with metastatic (10) or recurrent (11) disease were entered on a prospective feasibility study of intensive myeloablative therapy with or without TBI. Median patient age was 17.8 years (range, 9.4-24.7 years). Primary histologies included Ewing's (12), PNET (3), and other soft tissue sarcomas (6). Twenty patients received induction chemotherapy. Myeloablative therapy consisted of TBI in 11 patients with either high dose melphalan/etoposide (9) or high dose cytoxan/thiotepa (2). TBI consisted of 12 Gy in 2 Gy fractions delivered twice daily over 3 days. Ten patients received high dose chemotherapy alone, either with thiotepa/carboplatinum/etoposide (8) or cytoxan/carboplatinum (2). Myeloablative therapy was followed by autologous stem cell rescue (ASCR) 24 to 48 hours after completing chemotherapy. Fourteen patients (67%) received CRT either prior to (5) or following (9) myeloablative therapy. Median CRT dose was 37.2 Gy (range, 20-60). Fifty-one disease sites were present prior to myeloablative therapy. Twelve (24%) were bulky (> 8 cm) and 18 (35%) underwent surgical debulking. The median follow-up of surviving patients was 15 months (range, 8-20) with 25% of patients having been followed for more than 20 months. RESULTS: The 3-year actuarial disease-free (DFS) and overall survival (OS) rates for the entire group were 36% and 27%, respectively. Following myeloablative treatment, responses were: 11 complete, 6 partial, 1 stable, and 3 progressive disease. Sixteen patients (71%) have relapsed. The most common site of relapse was the lung (13). Of the 51 disease sites present prior to myeloablative therapy, 36 sites (71%) were amenable to CRT. Nonamenable sites were: multiple lung metastases (13) and bone marrow (2). Twenty-six amenable sites (51%) received CRT either prior to (14) or following (12) ASCR. Amenable sites treated with CRT had a better 3-year actuarial local control (80 vs 37%) (p = 0.0065) than amenable sites not treated with CRT. Factors associated with improved disease-free survival (DFS) in univariate analysis were induction chemotherapy response (p = 0.002) and extent of surgical resection (p = 0.045). There was a trend toward improved DFS on univariate analysis with the use of TBI as part of myeloablative therapy (p = 0.07). The one factor associated with improved OS on univariate analysis was induction chemotherapy response (p = 0.007). Multivariate analysis revealed that induction chemotherapy response is the only factor that remains significant for DFS (p = 0.032) as well as for OS (p = 0.017). Patients with complete response to induction therapy had 40% probability of survival versus all other patients who had 10% survival (p = 0.05). CONCLUSION: Consolidative radiotherapy is feasible in primary metastatic or recurrent pediatric sarcoma patients treated with myeloablative therapy with or without TBI. CRT to sites amenable to irradiation provided an improved 3-year actuarial local control than that seen in sites amenable to CRT that did not undergo radiotherapy. There was a trend for improved DFS with the use of TBI. Improved DFS and OS can be predicted by response to induction therapy. This intensive regimen may improve the cure rate of advanced pediatric sarcomas in select patients.

Bone marrow suppression after strontium-89 therapy and local radiation therapy in patients with diffuse marrow involvement.

Strontium-89 is routinely used for pain control in advanced skeletal metastatic disease. A common side effect of Sr-89 therapy is a mild to moderate bone marrow suppression. To avoid complications from marrow suppression, a pretreatment platelet count of > 60,000/mm3 and a WBC count of > 2,400/mm3 are suggested. The authors present two patients who, despite satisfying these criteria, developed profound and prolonged bone marrow suppression after therapy. The severity of this response was most likely caused by pre-existing extensive bone marrow replacement with tumor. The contribution of local radiation therapy to bone marrow suppression is presumed to be minimal. The authors recommend that pretreatment criteria for determination of eligibility for Sr-89 therapy in selected patients be expanded to include steadily decreasing blood counts, and evaluation of extent of marrow involvement by biopsy or MR imaging.