Total body irradiation (TBI) in pediatric patients. A single-center experience after 30 years of low-dose rate irradiation.

PURPOSE: To retrospectively analyze patient characteristics, treatment, and treatment outcome of pediatric patients with hematologic diseases treated with total body irradiation (TBI) between 1978 and 2006. PATIENTS AND METHODS: 32 pediatric patients were referred to the Department of Radiation-Oncology at the University of Zurich for TBI. Records of regular follow-up of 28 patients were available for review. Patient characteristics as well as treatment outcome regarding local control and overall survival were assessed. A total of 18 patients suffered from acute lymphoblastic leukemia (ALL), 5 from acute and 2 from chronic myelogenous leukemia, 1 from non-Hodgkin lymphoma, and 2 from anaplastic anemia. The cohort consisted of 15 patients referred after first remission and 13 patients with relapsed leukemia. Mean follow-up was 34 months (2-196 months) with 15 patients alive at the time of last follow-up. Eight patients died of recurrent disease, 1 of graft vs. host reaction, 2 of sepsis, and 2 patients died of a secondary malignancy. RESULTS: The 5-year overall survival rate (OS) was 60%. Overall survival was significantly inferior in patients treated after relapse compared to those treated for newly diagnosed leukemia (24% versus 74%; p=0.004). At the time of last follow-up, 11 patients survived for more than 36 months following TBI. Late effects (RTOG ≥ 3) were pneumonitis in 1 patient, chronic bronchitis in 1 patient, cardiomyopathy in 2 patients, severe cataractogenesis in 1 patient (48 months after TBI with 10 Gy in a single dose) and secondary malignancies in 2 patients (36 and 190 months after TBI). Growth disturbances were observed in all patients treated prepubertally. In 2 patients with identical twins treated at ages 2 and 7, a loss of 8% in final height of the treated twin was observed. CONCLUSION: As severe late sequelae after TBI, we observed 2 secondary malignancies in 11 patients who survived in excess of 36 months. However, long-term morbidity is moderate following treatment with the fractionated TBI at the low-dose rate that was generally used here. Conditioning for bone marrow transplantation without radiation is an attractive option, but is not sufficiently effective to completely replace TBI for the most common pediatric indications.

Prophylaxis of heterotopic ossification in patients sedated after polytrauma : medical and ethical considerations.

BACKGROUND AND PURPOSE: Heterotopic ossification (HO) often follows acetabular fractures after multitrauma. Irradiation is a mean for prophylaxis. We established a standard procedure in our hospital for patients under sedation, when obtaining informed consent for HO prophylaxis is impossible. PATIENTS AND METHODS: We reviewed current scientific evidence, calculated the risks of radiation and presented the ethical and legal framework. The subject was scrutinised by an interdisciplinary panel. RESULTS: Irradiation is the most effective means for prophylaxis and has few adverse effects in adult patients with fractures of the acetabulum. The lifetime risk of radiation-induced cancer or infertility are insignificant. CONCLUSIONS: Informed consent for irradiation should be obtained before operation whenever possible. When this cannot be done prophylaxis can be postponed for a maximum of 3 days in order to obtain consent. If the patient is not able to communicate within this period, prophylactic irradiation should be given after consulting the relatives. The patient must be informed as soon as possible.

[Recommendations for dental care prior to intensity-modulated radiotherapy (IMRT). Adaptation of the University Hospital Zurich (USZ) guidelines]. / Empfehlung für die Zahnsanierung vor intensitäts-modulierter Radiotherapie (IMRT). UniversitätsSpital Zürich (USZ)-Richtlinien-Anpassung.

This article is aimed to inform about the recently performed adjustments of the established standard procedures for pre-radiotherapeutic dental care (GROTZ 2003; Shaw et al. 2000) on intensity modulated radiation therapy (IMRT) at the Department of Radiation Oncology, University Hospital Zurich (USZ). The adjustments described base on prospectively assessed results and clinical observations of more than 300 head and neck cancer patients treated with definitive or postoperative IMRT at the own institution. In order to explain the clinical differences between conventional radiation techniques and IMRT, a brief introduction section addresses characteristics of IMRT delivery, optimization of normal tissue sparing, and resulting improved normal tissue tolerance (Fig. 1a-c). In conclusion, careful adjustments of pre-treatment dental care as proposed (Tab. I) are recommended for IMRT patients. This requires close case-related interdisciplinary cooperation between the referring radiation oncologist and the dentist or dental care centre, respectively. The depicted sketches (Fig. 2) are thought to get completed by the radiation oncologist, in order to inform the dentist about topographic risk areas/levels for radiation-induced late effects.

IMRT in hypopharyngeal tumors.

BACKGROUND AND PURPOSE: Intensity-modulated radiation therapy (IMRT) data on hypopharyngeal cancer (HC) are scant. In this study, the authors report on early results in an own HC patient cohort treated with IMRT. A more favorable outcome as compared to historical data on conventional radiation techniques was expected. PATIENTS AND METHODS: 29 consecutive HC patients were treated with simultaneous integrated boost (SIB) IMRT between 01/2002 and 07/2005 (mean follow-up 16 months, range 4-44 months). Doses of 60-71 Gy with 2.0-2.2 Gy/fraction were applied. 26/29 patients were definitively irradiated, 86% received simultaneous cisplatin-based chemotherapy. 60% presented with locally advanced disease (T3/4 Nx, Tx N2c/3). Mean primary tumor volume measured 36.2 cm(3) (4-170 cm(3)), mean nodal volume 16.6 cm(3) (0-97 cm(3)). RESULTS: 2-year actuarial local, nodal, distant control, and overall disease-free survival were 90%, 93%, 93%, and 90%, respectively. In 2/4 patients with persistent disease (nodal in one, primary in three), salvage surgery was performed. The mean dose to the spinal cord (extension of > 5-15 mm) was 26 Gy (12-38 Gy); the mean maximum (point) dose was 44.4 Gy (26-58.9 Gy). One grade (G) 3 dysphagia and two G4 reactions (laryngeal fibrosis, dysphagia), both following the schedule with 2.2 Gy per fraction, have been observed so far. Larynx preservation was achieved in 25/26 of the definitively irradiated patients (one underwent a salvage laryngectomy); 23 had no or minimal dysphagia (G0-1). CONCLUSION: Excellent early disease control and high patient satisfaction with swallowing function in HC following SIB IMRT were observed; these results need to be confirmed based on a longer follow-up period. In order to avoid G4 reactions, SIB doses of < 2.2 Gy/fraction are recommended for large tumors involving laryngeal structures.

Osteoradionecrosis of the mandible: minimized risk profile following intensity-modulated radiation therapy (IMRT).

BACKGROUND AND PURPOSE: Osteoradionecrosis (ON) of the mandible is a serious late complication of high-dose radiation therapy for tumors of the oropharynx and oral cavity. After doses between 60 and 72 Gy using standard fractionation, an incidence of ON between 5% and 15% is reported in a review from 1989, whereas in more recent publications using moderately accelerated or hyperfractionated irradiation and doses between 69 and 81 Gy, the incidence of ON is between < 1% and ~ 6%. Intensity-modulated radiation therapy (IMRT) is expected to translate into a further important reduction of ON. The aim of this descriptive study was to assess absolute and relative bone volumes exposed to high IMRT doses, related to observed bone tolerance. PATIENTS AND METHODS: Between December 2001 and November 2004, 73 of 123 patients treated with IMRT were identified as subgroup "at risk" for ON (> 60 Gy for oropharyngeal or oral cavity cancer). 21/73 patients were treated in a postoperative setting, 52 patients underwent primary definitive irradiation. In 56 patients concomitant cisplatin-based chemotherapy was applied. Mean follow-up time was 22 months (12-46 months). Oral cavity including the mandible bone outside the planning target volume was contoured and dose-volume constraints were defined in order to spare bone tissue. Dose-volume histograms were obtained from contoured mandible in each patient and were analyzed and related to clinical mandible bone tolerance. RESULTS: Using IMRT with doses between 60 and 75 Gy (mean 67 Gy), on average 7.8, 4.8, 0.9, and 0.3 cm(3) were exposed to doses > 60, 65, 70, and 75 Gy, respectively. These values are substantially lower than when using three-dimensional conformal radiotherapy. The difference has been approximately quantified by comparison with a historic series. Additional ON risk factors of the patients were also analyzed. Only one grade 3 ON of the lingual horizontal branch, treated with lingual decortication, was observed. CONCLUSION: Using IMRT, only very small partial volumes of the mandibular bone are exposed to high radiation doses. This is expected to translate into a further reduction of ON and improved osseointegration of dental implants.