Slipped femoral capital epiphyses in irradiated children: dose, volume and age relationships

Bone complications of cancer treatment

With the advancements in conventional treatment modalities such as radiation, chemotherapy, and surgery, as well as the emergence of immunotherapy, the overall cure rate for solid tumor malignancies has experienced a significant increase. However, it is unfortunate that exposure to cancer treatments can have detrimental effects on the function of osteoblasts and osteoclasts, disturbing bone metabolic homeostasis in patients, as well as causing damage to bone marrow cells and other bone tissues. Consequently, certain tumor treatment options may pose a risk for subsequent bone diseases. Common bone disorders associated with cancer treatment include osteonecrosis, bone loss, and secondary bone tumors. (1)Cancer treatment-related osteonecrosis is primarily linked to the use of radiation therapy and certain chemicals, such as bisphosphonates, denosumab, antiangiogenic agents, and immunomodulators. It has been observed that high-dose radiation therapy is more likely to result in osteonecrosis. (2)Chemicals and hormones, particularly sex hormones, glucocorticoids, and thyroid hormones or thyrotropic hormones, are among the factors that can contribute to cancer treatment-related bone loss. (3)Secondary bone tumors differ from metastases originating from primary tumors, and radiotherapy plays a significant role in their development, while chemotherapy may also exert some influence. Radiogenic secondary bone tumors are predominantly malignant, with osteosarcoma being the most common type. Chemotherapy may be a risk factor for the relatively rare occurrence of secondary Ewing sarcoma of the bone. These treatment-related bone disorders have a considerable adverse impact on the prognosis of cancer patients. Hence, it is imperative to prioritize the bone health of patients undergoing cancer treatment and give it further attention.

A Road Map for Important Centers of Growth in the Pediatric Skeleton to Consider During Radiation Therapy and Associated Clinical Correlates of Radiation-Induced Growth Toxicity

With the increasing use of advanced radiation techniques such as intensity modulated radiation therapy, stereotactic radiation therapy, and proton therapy, radiation oncologists now have the tools to mitigate radiation-associated toxicities. This is of utmost importance in the treatment of a pediatric patient. To best use these advanced techniques to mitigate radiation-induced growth abnormalities, the radiation oncologist should be equipped with a nuanced understanding of the anatomy of centers of growth. This article aims to enable the radiation oncologist to better understand, predict, and minimize radiation-mediated toxicities on growth. We review the process of bone development and radiation-induced growth abnormalities and provide an atlas for contouring important growth plates to guide radiation treatment planning. A more detailed recognition of important centers of growth may improve future treatment outcomes in children receiving radiation therapy.

Comparison of different adjuvant radiotherapy approaches in childhood bladder/prostate rhabdomyosarcoma treated with conservative surgery

BACKGROUND AND PURPOSE

Multimodality treatment approaches provide high local control and satisfying overall survival (OS) for children with localized bladder and/or prostate rhabdomyosarcoma (BP-RMS). However, current strategies including surgery and conventional radiotherapy are compromised by high rates of long-term genitourinary adverse effects. Therefore, a planning study combining organ preserving surgery with three different innovative adjuvant radiotherapy approaches was performed.

PATIENTS AND METHODS

A case of a 21-month-old boy with BP-RMS treated with polychemotherapy according to the CWS 2002-P protocol, prostatectomy, partial cystectomy, and adjuvant high dose rate brachytherapy (HDR-BT) was used to perform a planning study comparing HDR-BT with intensity-modulated radiotherapy (IMRT) and intensity-modulated proton therapy (IMPT) planning.

RESULTS

All modalities provide good coverage of the target volume and spare critical normal tissues. Rectum doses could be reduced by 2/3 using IMPT and by 1/3 using BT compared to IMRT. In terms of sparing the pelvis growth plates, BT and IMPT are also superior to IMRT.

CONCLUSION

All modalities provide good sparing of normal tissue. BT and IMPT are superior to IMRT with regard to doses on rectum and growth plates. BT is equivalent to IMPT in adequately selected tumors.

A long term results of external beam radiation therapy in hemophilic arthropathy of the ankle in children

Bleeding into joint space is critical to develop hemophilic arthropathy. To reduce the frequency of bleeding in the ankle joint of children with hemophilic arthropathy, low dose external beam irradiation was performed for 37 patients. Among them, 35 patients followed-up for longer than 1 yr (median 87 months) were enrolled for analysis. The average number of bleedings per month was 3.6 during one year prior to radiation therapy. After radiation therapy, it was decreased to 2.1 during the first year, after then it was maintained in the range of 1.0 to 1.5 until the tenth year. The bleeding frequency was reduced to 42% at the first year and it was maintained in the range of 58% to 73% from the second to the tenth year. Especially the patients who had 3 or more bleedings per month, and who had MRI score more than 3 showed significant decreases. During the follow-up period, growth disturbances and secondary malignancies were not found. External beam radiotherapy can be considered for the hemophilic patients with surgical or isotope therapies are not amenable.

Normal tissue development, homeostasis, senescence, and the sensitivity to radiation injury across the age spectrum

Late effects in normal tissues following radiotherapy vary across the age spectrum. It seems that sensitivity to radiation injury is a function of the developmental dynamics and status of the organ, its regenerative potential, and ultimately the extent to which it has begun to senesce. For instance, organ maturational processes in children can be impaired or even disabled by radiation therapy, leading to a spectrum of effects that differ from those in adults, in which the capacity and means for tissues to repair damage are the predominant predictor for chronic injury. Thus, radiation-induced impairment of growth and maturation is unique to children, whereas organ damage, with tissue-specific dysfunction in repair processes, is common to both children and adults. Finally, the susceptibility to late effects in the elderly seems to involve not only a decline in their ability to repair damage, but also cell attrition, all intertwined with effects of comorbid illness that are frequent in this age group. The challenge for clinicians is to understand these differences in the sensitivity to radiation damage with respect to age to formulate a basis for modulating therapy that can rationally minimize late effects and maximize a survivor's quality of life.

The effect of X-rays on bone: a pictorial review

The deleterious effects of X-rays on bone have been recognised for almost a century and continue to be seen today because of improved survival in patients treated for malignancy with radiotherapy with or without other treatments. In this pictorial review we present the imaging features of radiation damage to bone highlighting the differences seen in the immature skeleton and post-skeletal fusion. In the former, damage is greatest to the physis resulting in growth disturbances. In the mature skeleton there is a spectrum of changes from mild osteopenia, through disordered attempts at healing with varying degrees of sclerosis, radionecrosis which may lead to acute fractures following minimal trauma and insufficiency fractures both with refractory healing to the dreaded complication of sarcomatous transformation. The imaging appearances are illustrated and the features that help distinguish malignant change from other complications stressed.

Atypical slipped capital femoral epiphysis after radiotherapy and chemotherapy

Atypical slipped capital femoral epiphysis after radiotherapy and chemotherapy is uncommon. Only 32 cases have been reported in the literature. Because patients may have slippage at atypical ages, we report two cases of slipped capital femoral epiphysis in children and review the 32 cases previously reported to heighten clinicians' awareness of this condition in patients who have received radiation and chemotherapy for pelvic tumors. The controversy over prophylactic pinning of the uninvolved hip in radiotherapy-associated slipped capital femoral epiphysis is unresolved. It may be justifiable to fix the nonslipped epiphysis if possible prodromal signs of abnormal radiographic findings are detected. Because radiotherapy and chemotherapy were used in the two children reported, it is not possible to state whether one or both forms of treatment were responsible for the atypical slipped capital femoral epiphysis.

Radiotherapy for pediatric genitourinary tumors. Its role and long-term consequences

Radiation therapy has traditionally played a major role in the treatment of pediatric genitourinary malignancies. In particular, Wilms' tumor, rhabdomyosarcoma, and neuroblastoma often include radiotherapy in the local control phase of treatment. Recently, clinical trials have focused on decreasing the toxicity of radiotherapy through dose modifications and conformal field arrangements. Radiotherapy will continue to be a major treatment modality for this patient group if technologic advances in radiation delivery continue to increase efficacy without comorbidities.

Skeletal complications in pediatric oncology patients

Pediatric oncology patients are at risk for the development of numerous skeletal complications, and radiologic studies are important in the identification and evaluation of these conditions. Methotrexate osteopathy manifests as osteopenia, dense provisional zones of calcification, pathologic fractures, and sharply outlined epiphyses. Hypertrophic osteoarthropathy may occur with nasopharyngeal carcinoma or tumors of the lungs or pleura and manifests as cortical thickening, lamellar periosteal new bone formation, and soft-tissue swelling. Biomechanical abnormalities are often seen at bone scintigraphy in patients who have undergone surgery for bone tumors. Growth plate injury may manifest as marked deformity, sclerotic metaphyseal bands, metaphyseal fraying, and longitudinal striations. Radiation "osteitis" is seen as an initial decrease in bone density with subsequent development of a mixed radiolucent and sclerotic appearance. Ischemic necrosis of the femoral heads is best demonstrated at magnetic resonance (MR) imaging and has low signal intensity on T1-weighted images and a high-signal-intensity rim on T2-weighted images. Bone infarcts are seen as well-demarcated, often ring-shaped areas of decreased signal intensity on T1-weighted MR images and as areas of increased signal intensity on short-inversion-time inversion recovery images. Radiographic signs of infection include bone destruction, periosteal new bone formation, and sclerotic changes. Short-inversion-time inversion recovery MR imaging is particularly useful in evaluating posttherapy changes in bone marrow. Osteochondroma may demonstrate a cartilaginous cap at MR imaging, whereas the most important finding in radiation-induced sarcoma is a soft-tissue mass. Radiologists who work with children with cancer need to be familiar with these complications and their imaging appearances.

Response of growing bone to irradiation: a proposed late effects scoring system

The effect of radiation on epiphyseal bone growth is one of the most important dose-limiting factors in the radiotherapeutic management of children with malignant neoplasms. Clinical and laboratory evidence suggest that many factors may influence the severity of radiation-induced growth arrest. However, the absence of a consistent scoring system for late effects has hampered efforts to analyze the influence of various therapeutic maneuvers or to compare and collate results from different reported series. In this review, laboratory and clinical studies of radiation effects on growing bone are summarized, and a late effects scoring system is proposed.

In vivo, three-dimensional microscopy of trabecular bone

Osteoporosis, which is correlated with low bone mass and increased bone fragility, is responsible for about 1.2 million fractures per year in the United States. We have used the three-dimensional (3-D), X-ray tomographic microscope to image the trabecular bone architecture of the proximal tibias of six Sprague-Dawley rats in vivo. Three of these rats were then ovariectomized to induce estrogen depletion, and three remained as controls. Five weeks later, the tibias were reimaged. The ovariectomized rats lost approximately 65% of their trabecular bone volume as compared with an insignificant change in the control rats. The connectivity density of the trabecular bone, as measured by the Euler characteristic, was linearly correlated with trabecular bone volume, even in the ovariectomized rats. Hypoestrogenemic bone loss manifested itself in greatly reduced connectivity and fewer trabecular elements, but not in thinning of trabeculae. The ability to microscopically image sequential changes in the 3-D architecture of trabecular bone in vivo will allow exploration of the earliest stages of hypoestrogenemic bone loss and to more rapidly test the effectiveness of new clinical treatments for this major public health problem.

Postradiation slipped capital femoral epiphyses (SCFE)

This study details the case reports of two children who developed slipped capital femoral epiphyses (SCFE) after receiving external irradiation. The clinical and diagnostic features of postradiation SCFE are reviewed and discussed. Guidelines for the management of children who receive pelvic irradiation are presented.

A pertrochanteric fracture in an adolescent treated for an osteogenic sarcoma of the shaft of the femur with chemotherapy, tumour resection and endoprosthesis

Osteosarcomas of the femur are treated nowadays, if possible, by chemotherapy, resection of the tumor and reconstruction with an endoprosthesis. There is not only a risk of epiphyseal fractures in the long bones due to chemotherapy but also of a fracture in the remnant of the treated femur. These fractures should be treated conservatively because of the risk of infection and non-union if treated operatively.

Epiphyseal fractures in children treated for osteosarcoma of the femur with chemotherapy, tumourresection, and endoprosthesis: report of four fractures in two children

This paper reports on two patients, who both were under treatment for osteosarcoma of the femur. Treatment consisted of chemotherapy, resection of the tumour, and reconstruction with an endoprosthesis . Both patients sustained an epiphyseal fracture on two occasions after a minor trauma. Careful observations of the x-rays, including tomography, reveals that a metaphyseal anomaly could be the cause of these fractures. It is suggested that these metaphyseal changes are caused by chemotherapeutic agents. All fractures healed well after a conservative treatment.