Clinically relevant radioresistant rhabdomyosarcoma cell lines: functional, molecular and immune-related characterization

BACKGROUND

The probability of local tumor control after radiotherapy (RT) remains still miserably poor in pediatric rhabdomyosarcoma (RMS). Thus, understanding the molecular mechanisms responsible of tumor relapse is essential to identify personalized RT-based strategies. Contrary to what has been done so far, a correct characterization of cellular radioresistance should be performed comparing radioresistant and radiosensitive cells with the same isogenic background.

METHODS

Clinically relevant radioresistant (RR) embryonal (RD) and alveolar (RH30) RMS cell lines have been developed by irradiating them with clinical-like hypo-fractionated schedule. RMS-RR cells were compared to parental isogenic counterpart (RMS-PR) and studied following the radiobiological concept of the "6Rs", which stand for repair, redistribution, repopulation, reoxygenation, intrinsic radioresistance and radio-immuno-biology.

RESULTS

RMS-RR cell lines, characterized by a more aggressive and in vitro pro-metastatic phenotype, showed a higher ability to i) detoxify from reactive oxygen species; ii) repair DNA damage by differently activating non-homologous end joining and homologous recombination pathways; iii) counteract RT-induced G2/M cell cycle arrest by re-starting growth and repopulating after irradiation; iv) express cancer stem-like profile. Bioinformatic analyses, performed to assess the role of 41 cytokines after RT exposure and their network interactions, suggested TGF-β, MIF, CCL2, CXCL5, CXCL8 and CXCL12 as master regulators of cancer immune escape in RMS tumors.

CONCLUSIONS

These results suggest that RMS could sustain intrinsic and acquire radioresistance by different mechanisms and indicate potential targets for future combined radiosensitizing strategies.

Prospective evaluation of multitarget treatment of pediatric patients with helical intensity-modulated radiotherapy

Background and purpose

Radiotherapy (RT) is persistently gaining significance in the treatment of pediatric tumors. However, individual features of a growing body and multifocal stages complicate this approach. Tomotherapy offers advantages in the treatment of anatomically complex tumors with low risks of side effects. Here we report on toxicity incidence and outcome of tomotherapy with a focus on multitarget RT (mtRT).

Materials and methods

From 2008 to 2017, 38 children diagnosed with sarcoma were treated with tomotherapy. The median age was 15 years (6–19 years). Toxicity was graded according to the Common Terminology Criteria for Adverse Events v.4.03 and classified into symptoms during RT, acutely (0–6 months) and late (>6 months) after RT, and long-term sideeffects (>24 months).

Results

The main histologies were Ewing sarcoma (n = 23 [61%]) and alveolar rhabdomyosarcoma (n = 5 [13%]). RT was performed with a median total dose of 54 Gy (40.5–66.0 Gy) and a single dose of 2 Gy (1.80–2.27 Gy). Twenty patients (53%) received mtRT. Median follow-up was 29.7 months (95% confidence interval 15.3–48.2 months) with a 5-year survival of 55.2% (±9.5%). The 5‑year survival rate of patients with mtRT (n = 20) was 37.1 ± 13.2%, while patients who received single-target RT (n = 18) had a 5-year survival rate of 75 ± 10.8%. Severe toxicities (grade 3 and 4) emerged in 14 patients (70%) with mtRT and 7 patients (39%) with single-target RT. Two non-hematological grade 4 toxicities occurred during RT: one mucositis and one radiodermatitis. After mtRT 5 patients had grade 3 toxicities acute and after single-target RT 4 patients. One patient had acute non-hematological grade 4 toxicities (gastritis, pericarditis, and pericardial effusion) after mtRT. Severe late effects of RT occurred in 2 patients after mtRT and in none of the single-target RT patients. No severe long-term side effects appeared.

Conclusion

Our results showed acceptable levels of acute and late toxicities, considering the highly advanced diseases and multimodal treatment. Hence, tomotherapy is a feasible treatment method for young patients with anatomically complex tumors or multiple targets. Especially mtRT is a promising and innovative treatment approach for pediatric sarcomas, delivering unexpectedly high survival rates for patients with multifocal Ewing sarcomas in this study, whereby the limited number of patients should invariably be considered in the interpretation.

Electronic supplementary material

The online version of this article (10.1007/s00066-020-01670-4) contains supplementary material, which is available to authorized users.

Worse Outcomes for Head and Neck Rhabdomyosarcoma Secondary to Reduced-Dose Cyclophosphamide

PURPOSE

Recent trends, including the use of proton therapy and administration of reduced doses of cyclophosphamide, have been adapted in head and neck (HN) rhabdomyosarcoma (RMS) to reduce late morbidity. Our primary goal was to analyze local control and survival outcomes after photon versus proton irradiation in pediatric patients with HN-RMS, with the secondary goal of analyzing the effect of cyclophosphamide dose on disease outcomes.

METHODS AND MATERIALS

This single-institution cohort study comprised 76 pediatric HN-RMS patients treated with definitive chemoradiation from 2000 to 2018. Fifty-one patients (67%) received intensity modulated photon radiation therapy, and 25 (33%) received proton therapy.

RESULTS

Local failure (LF) at 2 years was 12.5% for parameningeal RMS and 0% for orbital RMS and other head and neck sites (P = .24). Patients treated with protons were more likely to have received reduced-dose cyclophosphamide (P < .0001). The 2-year LF was 7.9% in the intensity modulated photon radiation therapy cohort versus 14.6% in the proton cohort (P = .07), with no difference in survival outcomes. Cumulative cyclophosphamide dose was significantly associated with 2-year LF: 0% for cumulative dose of >20 g/m2 versus 15.3% for ≤20 g/m2 (P = .04). In parameningeal RMS patients (n = 59), both cumulative cyclophosphamide dose and dose intensity were associated with LF (P = .01). There was a trend toward worse event-free survival for parameningeal RMS patients who received reduced-dose-intensity cyclophosphamide (59.2% vs 70.6%, P = .11).

CONCLUSIONS

Both dose-intensity and cumulative cyclophosphamide dose seem to play an important role in achieving local control for HN-RMS patients treated with either protons or photons. Longer follow-up is needed to further assess disease outcomes with proton therapy.

Patterns of failure for rhabdomyosarcoma of the perineal and perianal region

PURPOSE

To analyze prognostic factors and patterns of failure for rhabdomyosarcoma of the perineal and perianal region (PRMS), with an emphasis on radiation therapy for locoregional control.

METHODS AND MATERIALS

Detailed records of all 14 patients treated for PRMS at Memorial Sloan-Kettering Cancer Center between 1998 and 2012 were reviewed. The Kaplan-Meier method was used to assess the event-free survival (EFS) and overall survival (OS), and a competing-risks analysis was used to assess the cumulative incidence of local, regional, and distant failures.

RESULTS

Median age was 15.8 years (range, 1.1-31.9 years). High-risk features were identified: 9 of 14 patients (64%) had group 3 disease and 3 of 14 (21%) had group 4; 11 of 14 tumors (78%) were alveolar; 12 of 14 tumors (86%) were ≥5 cm; and 9 of 14 patients (64%) had involved lymph nodes (N1). Of those aged ≥10 years at diagnosis, 9 of 10 (90%) had alveolar histology, all had tumors ≥5 cm, and 8 of 10 (80%) presented with N1 disease. The rates of local, regional, and distant failure at 5 years were 17%, 31%, and 52%, respectively. Although 3 of the 4 patients with regional failure received nodal irradiation, only one of the nodal failures occurred in the radiation therapy field. The 5-year EFS was 33%, and OS was 39%. Age ≥10 years was associated with poor outcomes: EFS was 13% in patients aged ≥10 years, compared with 75% in those aged <10 years (P=.04); the OS was 13% in patients aged ≥10 years, compared with 100% in those aged <10 years (P=.04).

CONCLUSIONS

Patients with PRMS, especially those aged ≥10 years, present with poor prognostic features and continue to have poor outcomes. Given the high incidence of regional node recurrence, we recommend prophylactic ilioinguinal lymph node irradiation for all patients aged ≥10 years. For children aged <10 years, nodal evaluation is essential to determine the role for lymph node irradiation.

Delayed radiotherapy following dose intensive chemotherapy for parameningeal rhabdomyosarcoma (PM-RMS) of childhood

PURPOSE

To evaluate the local control rates and survival rates of patients with Group III parameningeal rhabdomyosarcoma (PM-RMS) treated with a dose intensive chemotherapy regimen followed by irradiation.

MATERIALS AND METHODS

Twenty-six patients with group III, PM-RMS were enrolled in a prospective pilot trial at the Mayo Clinic, Rochester, MN and Children's Hospital and Regional Medical Center Seattle, WA. The median age at diagnosis was 8.5 years (range 1.5-19 years). The male to female patient ratio was 1.6:1. Twenty-three patients had embryonal histology with the remaining three alveolar. Risk factors indicating high risk disease included intracranial extension (10 patients), base of skull erosion (12 patients), and cranial nerve palsy (10 patients). The median follow-up period for all patients was 82 months (range 17-148 months). Patients were treated with an intensified chemotherapy regimen followed by definitive local irradiation at week 12 following further chemotherapy. The median time from initiation of chemotherapy to irradiation was 16 weeks (range 6-23). The median dose delivered was 50.4Gy (50.4-66.6Gy).

RESULTS

Response was assessed after the fourth course of chemotherapy. Three patients exhibited a complete response, 22 a partial response, and 1 patient had no response after two cycles of chemotherapy and proceeded to irradiation at week 6. The 5-year estimated event free survival was 81% (+/-15%, 95% CI). Two patients died from progressive metastatic disease; 1 patient died from secondary malignancy; and 2 patients died from locally progressive disease. The 5-year local control rate was 92% (+/-10.6%, 95% CI).

CONCLUSIONS

Treatment of group III PM-RMS patients with neo-adjuvant, intensive chemotherapy with a delay in irradiation resulted in excellent local-regional control rates and survival rates and may allow for a response-based radiotherapy approach.

["Spot-scanning" proton therapy for rhabdomyosarcomas of early childhood. First experiences at PSI]

PURPOSE

To evaluate the feasibility and acute toxicity of spot-scanning proton therapy under deep sedation in young children with rhabdomyosarcomas (RMS).

PATIENTS AND METHODS

Since 2004, children requiring sedation can be admitted for proton therapy at Paul Scherrer Institute (PSI), Villigen, Switzerland. Children under 5 years of age with RMS of the head and the trunk were analyzed. All children were enrolled in a multidisciplinary treatment protocol and prospective, standardized evaluation of side effects was performed.

RESULTS

Nine children were included aged 0.9-3.8 years (embryonal RMS in six, and alveolar, undifferentiated or nonclassified in one each). The tumor site was parameningeal (n = 4), orbital (n = 3), head and neck (n = 1), and prostate (n = 1). All children were in IRS group III. Total proton dose was 46-54 CGE (cobalt-gray equivalent). Only the myelotoxicity exceeded grade 3 or 4 (RTOG/EORTC).

CONCLUSION

Proton therapy for RMS in early children is feasible and well tolerated. The prospective standardized evaluation of toxicity and quality of life needs to be continued.

The challenging role of radiation therapy for very young children with rhabdomyosarcoma

PURPOSE

To evaluate local control and toxicity for very young children treated with multimodality therapy for rhabdomyosarcoma (RMS).

METHODS AND MATERIALS

From 1990 to 2004, 20 patients<or=36 months at diagnosis were treated at our institution. Nineteen underwent chemotherapy (CMT), surgery and/or intraoperative high-dose-rate brachytherapy (IOHDR), and external-beam radiation (EBRT). Median age was 17 months. Sites included extremity (7), trunk (5), parameningeal (4), orbit (1), head/neck (1), bladder/prostate (1). Histologies consisted of 10 embryonal (53%) and 9 alveolar/undifferentiated (47%). Ten had delayed gross total resection (GTR) at median time of 17 weeks after the start of CMT, and 8 of these underwent IOHDR. Median interval between start of CMT and EBRT was 18 weeks. Median EBRT dose was 36 Gy. EBRT technique was either intensity-modulated (11), three-dimensional (3), or two-dimensional (5). Functional outcome was assessed for patients alive>or=1 year after diagnosis (15) in terms of mild, moderate, or severe deficits.

RESULTS

Median follow-up was 33 months for survivors and 23 months for all patients. Two-year actuarial local control, event-free survival, disease-specific survival, and overall survival were 84%, 52%, 74%, and 62%, respectively. All patients who began EBRT<or=18 weeks after the start of CMT had their disease controlled locally. Five have mild deficits and 10 have no deficits.

CONCLUSIONS

A reduced dose of 36-Gy EBRT after delayed GTR may maximize local control while minimizing long-term sequelae for very young children with RMS, but unresectable tumors (e.g., parameningeal) require higher doses. Normal-tissue-sparing techniques such as intensity-modulated radiation therapy and IOHDR are encouraged. Local control may be maximized when EBRT begins <or=18 weeks after initiation of CMT, but further study is warranted. Longer follow-up is required to determine the full extent of late effects.

Use of a tissue expander and a polyglactic acid (Vicryl) mesh to reduce radiation enteritis: case report and literature review

Management of stage IV rhabdomyosarcoma comprises systemic chemotherapy with local control by conservative surgery and radiotherapy. Abdominal radiotherapy may lead to radiation enteritis causing such serious morbidity as malabsorption, fistulae or stricture formation. The risk increases with the dose of radiation and length of bowel involved. Various methods have been utilised to displace the bowel from the radiation field. Usually these are applied in patients requiring pelvic irradiation. We report a case of metastatic alveolar rhabdomyosarcoma requiring radiotherapy to the right renal bed. Effective displacement of small bowel from the tumour site was achieved by a combined use of a tissue expander and Vicryl mesh. There were no complications from the surgery. This is the first report discussing combined use of a tissue expander and Vicryl mesh to aid radiotherapy to the renal fossa in a paediatric patient.

Continent urinary reconstruction in rhabdomyosarcoma: a new approach

PURPOSE

The authors present here 5 cases of continent urinary diversion in rhabdomyosarcoma applying a recently described technique for the Mitrofanoff Principle devised by the authors.

METHODS

Two previously irradiated rhabdomyosarcoma patients presenting with residual bladder disease and massive sensitive urinary urgency underwent a transverse colonic reservoir with catheterizable stoma. Two other patients presenting with a Bricker conduit underwent conversion into an ileal reservoir. One patient underwent reconstruction after a cystectomy.

RESULTS

All patients were continent and able to perform continent intermittent catheterization.

CONCLUSIONS

The technique proved to be feasible for this group of patients. The authors believe that because of its simplicity, it should be an option of continent urinary diversion when the Mitrofanoff Principle is considered.

Sentinel lymph node mapping and biopsy: a potentially valuable tool in the management of childhood extremity rhabdomyosarcoma

Multimodal therapy, involving surgery, chemotherapy and radiation, now dominates the management of rhabdomyosarcoma (RMS) in childhood. Yet, despite improvements in these practices, extremity tumors continue to fare relatively poorly. Several investigators have identified prognostic factors that can be used to direct therapy and predict outcome. These factors include histology and metastatic disease, the latter requiring accurate staging to identify. The presence of lymph node metastases has been shown to be of prognostic significance and is incorporated into pre-treatment staging schemes. Up to 50% of all surgically evaluated nodes and 17% of clinically negative nodes in extremity RMS may harbor tumor, underscoring the increased risk of understaging the disease if accurate lymph node dissection is not undertaken. Despite its importance, there appears to be no standard format by which regional nodal status is evaluated in extremity RMS. Sentinel lymph node mapping and biopsy are a minimally invasive technique, currently used in the staging of adult breast cancer and melanoma. In adults, the technique is associated with optimum nodal yield and low morbidity. We describe a case in which sentinel node mapping and dissection were used to easily and accurately stage a distal upper extremity alveolar RMS in a child with clinically and radiologically negative regional lymph nodes. The procedure yielded no positive nodes, was associated with no morbidity and spared the child more extensive radiotherapy. We propose the further evaluation of this simple and innovative technique in the overall management of this childhood malignancy.

Volumetric considerations in radiotherapy for pediatric parameningeal rhabdomyosarcomas

PURPOSE

To assess the influence of radiation volume on outcome in pediatric parameningeal rhabdomyosarcomas (PM-RMSs).

METHODS AND MATERIALS

Thirty patients ranging in age from 2 to 18 years (median 6) with PM-RMS were treated at the Hospital of the University of Pennsylvania and the Children's Hospital of Philadelphia between August 1988 and December 1999. The histologic subtypes included embryonal (n = 26), alveolar (n = 3), and undifferentiated (n = 1). Twenty-seven patients had Group III and three had Group IV disease. Twenty-seven patients underwent biopsy only and three subtotal resection. All patients were treated with multiple-agent chemotherapy and external beam radiotherapy. In 8 patients, all of whom had intracranial tumor extension, the tumor and whole brain were treated as the initial volume. In the remaining patients, most of those treated before 1992 were treated to the prechemotherapy (CMT) tumor volume for the entire treatment up to the total dose, which ranged from 45 to 59.4 Gy (median dose 57.9). In contrast, patients treated after 1992 generally received radiation initially to the pre-CMT volume (30.6-40 Gy; median dose 36) followed by a conedown to the post-CMT volume to a final dose of 41.4-55.2 Gy (median 50.4).

RESULTS

With a median follow-up of 6.2 years (range 2.1-13.3), the actuarial 5-year overall survival, progression-free survival, and local control rate for the entire group was 82%, 76%, and 76%, respectively. Seven failures and five deaths have been documented. In univariate analysis, histologic type, tumor size, and age at diagnosis were found to be predictive of overall survival and local control. No statistically significant difference in overall survival or local control was seen between patients who received a conedown to the post-CMT volume (n = 13) and patients in whom the pre-CMT volume was included for the entire treatment (n = 9).

CONCLUSION

Radiotherapy delivered to children with PM-RMS using a shrinking field technique with a post-CMT volume boost was effective and appears to give results comparable to those of patients in whom the pre-CMT volume was treated for the entire course. The use of such tailored treatment fields is likely to lead to fewer late effects and warrants further investigation.

Tc-99m MDP, thallium-201 chloride and Tc-99m MAG3 renal uptake in subacute and chronic radiation nephritis compared

The authors present a comparison of the findings for thallium-201 (Tl-201), Tc-99m MAG3 and Tc-99m MDP in subacute and chronic radiation nephritis in a 9-yr-old boy who was treated by radiation therapy for alveolar rhabdomyosarcoma of the left chest wall by a radiation port that partially included the left kidney. Tl-201 imaging three and six months later showed a cortical defect in the left kidney due to radiation nephritis. Tc-99m MDP scan showed increased uptake on both occasions, but more marked in the subacute period than in the chronic period. Tc-99m MAG3 showed decreased concentration and increased cortical retention three months later. Six months after the radiation therapy, a cortical defect corresponding to the cortical area that showed increased parenchymal retention was more prominent in the Tc-99m MAG3 scan. In the present case, Tc-99m MDP, Tl-201 and Tc-99m MAG3 findings may provide useful information for understanding pathophysiological damage in the kidney after radiation.

Near-precise interchromosomal recombination and functional DNA topoisomerase II cleavage sites at MLL and AF-4 genomic breakpoints in treatment-related acute lymphoblastic leukemia with t(4;11) translocation

We analyzed the der(11) and der(4) genomic breakpoint junctions of a t(4;11) in the leukemia of a patient previously administered etoposide and dactinomycin by molecular and biochemical approaches to gain insights about the translocation mechanism and the relevant drug exposure. The genomic breakpoint junctions were amplified by PCR. Cleavage of DNA substrates containing the normal homologues of the MLL and AF-4 translocation breakpoints was examined in vitro upon incubation with human DNA topoisomerase IIalpha and etoposide, etoposide catechol, etoposide quinone, or dactinomycin. The der(11) and der(4) genomic breakpoint junctions both involved MLL intron 6 and AF-4 intron 3. Recombination was precise at the sequence level except for the overall gain of a single templated nucleotide. The translocation breakpoints in MLL and AF-4 were DNA topoisomerase II cleavage sites. Etoposide and its metabolites, but not dactinomycin, enhanced cleavage at these sites. Assuming that DNA topoisomerase II was the mediator of the breakage, processing of the staggered nicks induced by DNA topoisomerase II, including exonucleolytic deletion and template-directed polymerization, would have been required before ligation of the ends to generate the observed genomic breakpoint junctions. These data are inconsistent with a translocation mechanism involving interchromosomal recombination by simple exchange of DNA topoisomerase II subunits and DNA-strand transfer; however, consistent with reciprocal DNA topoisomerase II cleavage events in MLL and AF-4 in which both breaks became stable, the DNA ends were processed and underwent ligation. Etoposide and/or its metabolites, but not dactinomycin, likely were the relevant exposures in this patient.

[Tumors of the anterior skull base. Effects of perioperative imaging on adjuvant radiotherapy planning]

OBJECTIVES

Treatment of anterior skull base tumours is still considered being a major challenge for all involved disciplines. Surgical management, complications, as well as the role of imaging for multimodality treatment options should be evaluated critically.

PATIENTS AND METHODS

57 patients underwent interdisciplinary one step trans-basal approaches for resection of benign and malignant anterior fossa tumours. Beside assessment of surgical results and perioperative morbidity, in 13 patients with malignant tumours perioperative imaging was evaluated with regard to further possible radio-oncological treatment options.

RESULTS

Applying trans-basal approaches radical tumour resection could be achieved in all cases independent of tumor-size (diameter 12-114 mm). Permanent postoperative complications (until 6 months postoperatively) were found in 4 cases (7%), transient complications in 7 cases (12.3%). Evaluation of perioperative imaging showed a heterogen use of different imaging modalities and revealed lack of standardization, hampering further planning of radiation therapy.

CONCLUSION

Treatment of anterior skull base tumours requires a maximum level of standardization of perioperative imaging, to grant a successful surgical and radio-oncological interdisciplinary patient management.

Alveolar rhabdomyosarcoma of the uterine cervix

Alveolar rhabdomyosarcoma is an uncommon tumor occurring mostly in extremities of children and adolescents. This type of tumor located in the uterine cervix has not been reported previously. A case of pure alveolar rhabdomyosarcoma arising from the uterine cervix in a 45-year-old patient and having a very aggressive clinical course is described. The patient presented with rapidly progressive cervical tumor, which was originally diagnosed as mesonephroid adenocarcinoma. She was treated with a radical two-stage surgical procedure and postoperative external beam and intracavitary irradiation. Despite treatment, she developed metastatic disease and died 3 months after the surgery. The aggressive course of the disease at this location was consistent with that of the majority of alveolar rhabdomyosarcoma cases of other sites reported in literature. No standard effective treatment is known for this tumor in adult patients.

Solid alveolar rhabdomyosarcoma with a t(2;13)

We report a child with a progressive "solid alveolar rhabdomyosarcoma" in whom analysis of tumor cells revealed a t(2;13) translocation characteristic of the classical alveolar subtype. Both subtypes of alveolar rhabdomyosarcoma are associated with a poor response to treatment and the occurrence of this translocation in both is suggestive of a common biologic origin.

Sarcomas of the hand and foot: analysis of local control and functional result with combined modality therapy in extremity preservation

PURPOSE

The records of 28 patients with sarcomas of the hand and foot treated at the National Cancer Institute (NCI) between 1977 and 1992 were reviewed to assess local control and functional results.

METHODS AND MATERIALS

Histologic types included 15 cases of the Ewing's sarcoma family of tumors, 7 cases of alveolar rhabdomyosarcoma, and 6 cases of nonrhabdomyosarcoma soft tissue sarcomas. Median age of all patients was 18 years (range 4-61), with a median potential follow-up of 114 months following diagnosis. Surgery varied from incisional biopsies for Ewing's Sarcoma and rhabdomyosarcoma lesions to complete excision when possible for nonrhabdomyosarcoma soft tissue sarcoma lesions. Amputation was not primarily performed, except in two patients who underwent ray resections of hand lesions (patients 13 and 24). Radiotherapy generally consisted of 50 Gy/25 fractions (fx)/5 weeks for Ewing's Sarcoma, 54 Gy/30 fx/6 weeks for rhabdomyosarcoma, and 63 Gy/35 fx/7 weeks for nonrhabdomyosarcoma soft tissue sarcomas. Chemotherapy was administered on various NCI protocols.

RESULTS

Actuarial local control for Ewing's Sarcoma was 84% at 5 and 10 years. All but one survivor are capable of hand/foot function for routine activities without orthotic requirements. Five of six patients (83%) who died of metastatic disease had functional distal extremities. Actuarial local control for rhabdomyosarcomas was 100%, with equivalent function. No patient developed a second malignancy in the treatment field.

CONCLUSIONS

Although equivalent local control may be achieved in these lesions with either amputation or radiotherapy, a prudent management course would be to defer amputation for management of local recurrences. Many patients with these lesions fail in distant sites only and die without local failure. For these patients and for those who remain long-term survivors, we believe a functional hand and foot provides a better quality of life than a prosthesis.

Acute myeloid leukemia in patients treated for rhabdomyosarcoma with cyclophosphamide and low-dose etoposide on Intergroup Rhabdomyosarcoma Study III: an interim report

The early occurrence of five cases of acute myeloid leukemia (AML) in children treated for primary rhabdomyosarcoma on the Intergroup Rhabdomyosarcoma Study III (IRS III) has prompted this report. These patients received cyclophosphamide and four received etoposide in addition to other agents. There were 1,062 eligible patients entered on IRS III between 1984 and 1991. Following surgery, treatment consisted of multiagent chemotherapy and radiotherapy in select clinical groups. Median follow-up time is 3.7 years (range 0-7.4 years). Incidence densities and odds ratios for AML were calculated for various treatment groups. Five cases of secondary AML have been reported through August 1992. A single case of osteogenic sarcoma was reported in the same period and a patient with myelodysplastic syndrome has occurred since that time. Median time to development of AML was 39 months. Incidence density of AML for patients receiving neither cyclophosphamide nor etoposide was 0, for those receiving cyclophosphamide but no etoposide it was 7.6, and when both agents were given, it was 51.6. The odds ratios of AML for the latter two groups indicated a risk of AML which was seven times higher in the patients who received both agents. A history of breast cancer was present in all five families of patients with AML and several other cancers had occurred in three families. Preliminary analysis suggests a possible causal role for low-dose etoposide in addition to that assumed for cyclophosphamide in the early development of AML among pediatric patients treated for rhabdomyosarcoma.