Radiation myelopathy following transplantation and radiotherapy for non-Hodgkin's lymphoma

Stereotactic Body Radiation Therapy for Spinal Metastases: Benefits and Limitations

Progress in biological cancer characterization, targeted systemic therapies and multimodality treatment strategies have shifted the goals of radiotherapy for spinal metastases from short-term palliation to long-term symptom control and prevention of compilations. This article gives an overview of the spine stereotactic body radiotherapy (SBRT) methodology and clinical results of SBRT in cancer patients with painful vertebral metastases, metastatic spinal cord compression, oligometastatic disease and in a reirradiation situation. Outcomes after dose-intensified SBRT are compared with results of conventional radiotherapy and patient selection criteria will be discussed. Though rates of severe toxicity after spinal SBRT are low, strategies to minimize the risk of vertebral compression fracture, radiation induced myelopathy, plexopathy and myositis are summarized, to optimize the use of SBRT in multidisciplinary management of vertebral metastases.

Multimodal PET/MRI Imaging Results Enable Monitoring the Side Effects of Radiation Therapy

Radiotherapy is one of the most frequently applied treatments in oncology. Tissue-absorbed ionizing radiation damages not only targeted cells but the surrounding cells too. The consequent long-term induced oxidative stress, irreversible tissue damage, or second malignancies draw attention to the urgent need of a follow-up medical method by which personalized treatment could be attained and the actually dose-limiting organ could be monitored in the clinical practice. We worked out a special hemisphere irradiation technique for mice which mimics the radiation exposure during radiotherapy. We followed up the changes of possible brain imaging biomarkers of side effects, such as cerebral blood flow, vascular endothelial function, and cellular metabolic processes for 60 days. BALB/c mice were divided into two groups (n=6 per group) based on the irradiation doses (5 and 20 Gy). After the irradiation procedure arterial spin labeling (ASL), diffusion-weighted imaging (DWI) in magnetic resonance modality and [¹⁸F]fluoro-deoxy-D-glucose positron emission tomography (FDG-PET) scans of the brain were obtained at several time points (3, 7, 30, and 60 days after the irradiation). Significant physiological changes were registered in the brain of animals following the irradiation by both applied doses. Elevated standard uptake values were detected all over the brain by FDG-PET studies 2 months after the irradiation. The apparent diffusion coefficients from DWI scans significantly decreased one month after the irradiation procedure, while ASL studies did not show any significant perfusion changes in the brain. Altogether, our sensitive multimodal imaging protocol seems to be an appropriate method for follow-up of the health status after radiation therapy. The presented approach makes possible parallel screening of healthy tissues and the effectiveness of tumor therapy without any additional radiation exposure.

Radiation-Induced Myelitis: Initial and Follow-Up MRI and Clinical Features in Patients at a Single Tertiary Care Institution during 20 Years

Myelitis is a rare complication of radiation exposure to the spinal cord and is often a diagnosis of exclusion. A retrospective review of clinical records and serial imaging was performed to identify subjects with documented myelitis and a history of prior radiation. Eleven patients fulfilled the inclusion criteria. All patients had longitudinally extensive cord involvement with homogeneous precontrast T1 hyperintense signal in the adjacent vertebrae, corresponding to the radiation field. T2 signal abnormalities involving the central two-thirds of the cord were seen in 6/11 patients (55%). The degree of cord expansion and contrast enhancement was variable but was seen in 6 (54%) and 5 (45%) patients, respectively. On follow-up, 2 patients developed cord atrophy, while complete resolution was noted in 1. Clinical improvement was noted in 5 patients, with symptom progression in 2 patients. Our results suggest that radiation myelitis is neither universally progressive nor permanent, and some radiographic and clinical improvement may occur.

Toxic and Metabolic Myelopathies

Myelopathy describes any neurologic deficit related to the spinal cord. It is most commonly caused by its compression by neoplasms, degenerative disc disease, trauma, or infection. Less common causes of myelopathy include spinal cord tumors, infection, inflammatory, neurodegenerative, vascular, toxic, and metabolic disorders. Conditions affecting the spinal cord must be recognized as early as possible to prevent progression that may lead to permanent disability. Biopsy is rarely performed, thus the diagnosis and management rely on patient׳s history, physical examination, laboratory results, and imaging findings. Here we review the clinical presentations, pathophysiological mechanisms, and magnetic resonance imaging findings of myelopathies related to metabolic or toxic etiologies.

Delayed radiation myelopathy: Differential diagnosis with positron emission tomography/computed tomography examination

Myelopathy is a rare but serious complication of radiation therapy (RT). Radiation myelopathy is white matter damage to the spinal cord developed after a certain period of application of ionizing radiation. Factors such as radiation dose and time between applications affect the occurrence as well as the severity of myelopathy. In those patients, positron emission tomography/computed tomography examination has a very important role both in the diagnosis and in the differential diagnosis of lesions. In this case report, the case of progressive paraparesis, developed in a 52-year-old female patient operated with pulmonary mucinous cystadenocarcinoma diagnosis and who received chemotherapy and RT following surgery, has been reported.

Clinical Outcomes After Reirradiation of Paraspinal Tumors

OBJECTIVE

We present our experience with reirradiation of locally recurrent paraspinal tumors using image-guided intensity modulated radiotherapy (IG-IMRT).

METHODS

We performed a retrospective review of 37 patients who were reirradiated using IG-IMRT for recurrent paraspinal tumors between 2000 and 2005. We evaluated radiation dose to the spinal cord or cauda equina in first and second radiation treatments, time to first recurrence, and clinical outcomes after reirradiation including second recurrence, survival, pain, functional status, and toxicity.

RESULTS

Median time to local failure after first radiation was 13 months. All patients underwent salvage reirradiation, postoperatively or with IG-IMRT alone. Median radiation dose to the planning target volume (PTV) was 2000 cGy; median spinal cord or cauda equina dose was 990 cGy. Median cumulative spinal cord or cauda equina dose was 4198 cGy. Local control probability at a median follow-up of 8 months was 60%; median interval to second failure was 13 months. Survival probability at a median follow up of 12 months was 72%; median survival was 18 months. Thirty-four patients (91%) reported stable or improved pain after second radiation, and 26 (70%) had a stable or improved functional status. Mild acute toxicity occurred in 3 patients (8%). No long-term toxicity has been identified.

CONCLUSIONS

Reirradiation using IG-IMRT is safe and achieves a meaningful interval of local control with improved symptoms. Further studies with more patients and longer follow up are needed to evaluate toxicity, predictors of failure, and timing of radiation after surgical salvage.

Treatment related myelitis in hodgkin’s lymphoma following stem cell transplant, chemotherapy and radiation: a case report and review of the literature

Radiation myelitis, while rare, is one of the most devastating complications of radiation treatment. We report here a case of a 25-year-old Middle Eastern man with progressive myelopathy 21 months following low dose irradiation of the cord in the context of high dose chemotherapy and stem cell rescue and a review of the literature.

Fatal radiation myelopathy after high-dose busulfan and melphalan chemotherapy and radiotherapy for Ewing's sarcoma: a review of the literature and implications for practice

Radiation myelopathy is a rare, devastating, late effect of radiotherapy to the spinal cord. Spinal cord tolerance is currently accepted as about 50 Gy in 1.8-2 Gy fractions. However, the effect of chemotherapy on cord tolerance is unclear. This issue is important, given the increasing use of chemotherapy in combination with radiotherapy. We describe the case of a 17-year-old boy with a right apical paraspinal Ewing's tumour in the neck treated with induction chemotherapy, high-dose chemotherapy (busulfan and melphalan) with peripheral stem-cell rescue and, 4 months later, radiotherapy to the primary tumour site (cervical cord received 50 Gy in 30 fractions). After a latent period of 4 months, he developed a progressive, severe and ultimately fatal radiation myelopathy, which we suggest was due to a synergistic interaction between the high-dose chemotherapy and the radiotherapy. The use of such chemotherapy regimens in Ewing's tumours should be carefully considered, particularly when radiotherapy encompassing the spinal cord is an essential component of management.

Optimal scheduling to reduce morbidity of involved field radiotherapy with transplantation for lymphomas: A Prospective Australasian Leukaemia and Lymphoma Group Study

This study evaluated delivery of involved field radiotherapy (IFRT) with transplantation for lymphomas timed to minimise toxicity. Patients transplanted for lymphoma had infradiaphragmatic disease irradiated pre-transplant and supradiaphragmatic disease post transplant. A total of 31 patients were studied, with a median follow-up duration of 4 years. Transplant conditioning was according to clinician preference. In all, 14 patients had pre-transplant abdominopelvic IFRT and 19 had post transplant IFRT (including three who had pre-transplant IFRT). Grade III-IV haematological toxicity from pre-transplant IFRT occurred in three patients and from post transplant IFRT in 10 patients. Pre-transplant IFRT had no effect on haematological recovery post transplant, but was associated with a trend towards increased gastrointestinal toxicity (P = 0.094). Pneumonitis due to post transplant thoracic IFRT occurred in one patient. Two patients failed in involved sites after completion of protocol radiotherapy. One case of myelodysplasia has been reported. As sequenced in this study, IFRT was feasible and produced a low incidence of severe pulmonary and haematological toxicities. Patient selection, field size and radiotherapy dose warrant further study.

Phase I study of involved-field radiotherapy preceding autologous stem cell transplantation for patients with high-risk lymphoma or Hodgkin's disease

PURPOSE

This Phase I study was designed to evaluate the tolerability of involved-field radiotherapy (IFRT) to areas of persistent disease in patients with high-risk Hodgkin's disease and non-Hodgkin's lymphomas before autologous stem cell transplantation (ASCT).

METHODS AND MATERIALS

Thirty-one patients with primary refractory or relapsed Hodgkin's disease (n = 13) and non-Hodgkin's lymphoma (n = 18) were treated with IFRT followed by high-dose chemotherapy and ASCT. All patients had bulky disease (> or =5 cm) and/or an inadequate response to salvage chemotherapy. The IFRT dose was escalated to a maximum of 36 Gy. Dose-limiting toxicity was defined as Grade 3-4 Bearman toxicity (life-threatening/fatal toxicity occurring within 28 days of ASCT). The chemotherapy regimen consisted of cyclophosphamide, etoposide, and carmustine.

RESULTS

The delivered dose of IFRT was 20 Gy in 9 patients, 28-30 Gy in 20, and 32-36 Gy in 2 patients to mediastinal (n = 19) and nonmediastinal (n = 12) sites. The median interval between IFRT completion and ASCT was 19 days. One patient developed Bearman Grade 3 hepatic toxicity. No other Grade 3 or 4 Bearman toxicity was observed. An increased requirement for i.v. narcotics was observed in patients treated with mediastinal IFRT vs. nonmediastinal IFRT (p = 0.02). A trend toward increased mucositis severity was seen in patients previously treated with a larger number of chemotherapy agents (p = 0.09) and in those with a shorter interval between IFRT and ASCT (p = 0.12). Pulmonary toxicity was more common in patients treated with mediastinal IFRT than in those treated with nonmediastinal IFRT (21% vs. 0%, p = 0.13). The 2-year overall and progression-free survival rate was 70% and 49% for all patients, 84% and 50% for patients with Hodgkin's disease, and 59% and 47% for patients with non-Hodgkin's lymphoma, respectively.

CONCLUSION

The maximal tolerated dose of IFRT was not reached when Grade 3-4 Bearman toxicity was dose limiting. Increased pulmonary toxicity and mucositis severity was seen after mediastinal IFRT compared with nonmediastinal IFRT. Because local control was excellent, higher doses of IFRT are not recommended. The absolute benefit of IFRT in this patient population needs investigation in future studies.

Neurologic complications of bone marrow transplantation

The various forms of HSCT are or will soon be accepted treatments for an ever-increasing number of hematologic and solid cancers. Attempts to reduce the mortality and morbidity of HSCT and at the same time preserve or increase its efficacy in tumor control include development of nonmyeloablative allogeneic stem-cell transplant strategies [208] and allogeneic laboratory research-enhancing graft acceptance [209,210]. Eventually, these efforts will reduce complication rates of HSCT, including neurologic complications. In the interim, the consultant neuro-oncologist or neurologist with a specific inteest in this field is faced with complex clinical syndromes, neuroradiologic imaging studies and neurophysiologic tests, and generally poorly understood pathophysiologic mechanisms. Prospective studies of HSCT patients in large transplantation centers using clinical registries are needed.

A PET study on the characterization of partially reversible radiogenic lower motor neurone disease

OBJECTIVE

To investigate the pathomechanism of the rare radiogenic lower motor neurone disease (LMND) on the basis of a case history involving a partial functional recovery.

PATIENT

A 31-year-old seminoma patient received postoperative para-aortic and para-iliac telecobalt irradiation with a biologically effective dose of 88 Gy(2) (44 Gy in 2 Gy fractions/day, with an estimated alpha/beta of 2 Gy) delivered to the spinal cord following a single cycle of chemotherapy. LMND developed 4 months after the completion of radiotherapy. The patient exhibited flaccid paraparesis of the lower extremities (without sensory or vegetative signs), followed by a worsening after further chemotherapy, due to pulmonary metastatization. A gradual spontaneous functional improvement commenced and led several years later to a stabilized state involving moderately severe symptoms.

METHODS

In the 15th year of the clinical course, magnetic resonance imaging (MRI) and positron emission tomography (PET) with [(18)F]fluorodeoxyglucose (FDG) and [(11)C] methionine were conducted. Four lines of experiments (clonogenic assay using fibroblasts isolated from a skin biopsy sample of the patient, comet assay, micronucleus assay, and the testing of chromosome aberrations after in vitro irradiation of peripheral blood samples) were performed in a search for an increased individual radiosensitivity.

RESULTS

MRI investigations failed to reveal any pathological change. PET demonstrated an increased FDG accumulation, but a negligible [(11)C] methionine uptake in the irradiated spinal cord segments. The radiobiological investigations did not indicate any sign of an increased individual radiosensitivity.

CONCLUSIONS

We suggest that the observed partial functional recovery and stabilization of the symptoms of radiogenic LMND may be explained by the higher than normal density of sodium channels expressed along the demyelinated axons of the restored conduction. The increased energy demands of this type of conduction are proved by a higher metabolic rate (increased FDG uptake) of the irradiated spinal cord segments without a substantial regenerative process (lack of detectable protein synthesis).

Radiation myelitis following allogeneic stem cell transplantation and consolidation radiotherapy for non-Hodgkin's lymphoma

Myelitis is a rare but well documented complication of therapeutic radiation exposure to the spinal cord and is characterized by delayed development of paresthesias, sensory changes and, in severe cases, progressive paresis and paralysis. Although accepted radiation tolerance limits for the spinal cord have successfully limited the incidence of this problem (45-50 Gy, in daily 1.8-2 Gy fractions), aggressive systemic therapy may render patients more susceptible to radiation-related neurotoxicity. We describe the case of a 38-year-old man with refractory non-Hodgkin's lymphoma who underwent matched sibling peripheral blood stem cell transplant following a conditioning regimen of cyclophosphamide (60 mg/kg x 2) and total body irradiation (120 cGy x 11). This was followed by delivery of 30.6 Gy involved-field radiation at 1.8 Gy/day to the mediastinum and left supraclavicular fossa for bulky residual tumor. Although maximum cumulative radiation dose to the spinal cord was less than 45 Gy, the patient subsequently developed progressive lower extremity weakness and MRI abnormalities of the spinal cord limited to the radiation field. This represents the second report in the literature of this unexpected complication, prompting a need to re-examine current guidelines for radiotherapy in the context of high-dose systemic treatment.

Clinical application of in vitro radiohypersensitivity testing

The cases of two patients who suffered severe late effects of radiotherapy are reported; each tested positive for elevated in vitro radiohypersensitivity (RHS) but negative for the ataxia-telangiectasia mutation. The first patient underwent surgery and postoperative radiotherapy for lung cancer and subsequently developed fatal myelopathy. The second patient underwent triple-modality therapy for cervical cancer and suffered highly symptomatic pelvic fibrosis. The value of the testing was that it increased the confidence in the diagnosis of radiation effects and enabled suitable treatment to proceed. An increasing role for clinical RHS testing is anticipated.