Total body irradiation with volumetric modulated arc therapy: Dosimetric data and first clinical experience.

BACKGROUND: To implement total body irradiation (TBI) using volumetric modulated arc therapy (VMAT). We applied the Varian RapidArc™ software to calculate and optimize the dose distribution. Emphasis was placed on applying a homogenous dose to the PTV and on reducing the dose to the lungs. METHODS: From July 2013 to July 2014 seven patients with leukaemia were planned and treated with a VMAT-based TBI-technique with photon energy of 6 MV. The overall planning target volume (PTV), comprising the whole body, had to be split into 8 segments with a subsequent multi-isocentric planning. In a first step a dose optimization of each single segment was performed. In a second step all these elements were calculated in one overall dose-plan, considering particular constraints and weighting factors, to achieve the final total body dose distribution. The quality assurance comprised the verification of the irradiation plans via ArcCheck™ (Sun Nuclear), followed by in vivo dosimetry via dosimeters (MOSFETs) on the patient. RESULTS: The time requirements for treatment planning were high: contouring took 5-6 h, optimization and dose calculation 25-30 h and quality assurance 6-8 h. The couch-time per fraction was 2 h on day one, decreasing to around 1.5 h for the following fractions, including patient information, time for arc positioning, patient positioning verification, mounting of the MOSFETs and irradiation. The mean lung dose was decreased to at least 80 % of the planned total body dose and in the central parts to 50 %. In two cases we additionally pursued a dose reduction of 30 to 50 % in a pre-irradiated brain and in renal insufficiency. All high dose areas were outside the lungs and other OARs. The planned dose was in line with the measured dose via MOSFETs: in the axilla the mean difference between calculated and measured dose was 3.6 % (range 1.1-6.8 %), and for the wrist/hip-inguinal region it was 4.3 % (range 1.1-8.1 %). CONCLUSION: TBI with VMAT provides the benefit of satisfactory dose distribution within the PTV, while selectively reducing the dose to the lungs and, if necessary, in other organs. Planning time, however, is extensive.

Treatment of Patients With Myelodysplastic Syndrome With Lenalidomide in Clinical Routine in Austria.

BACKGROUND: Lenalidomide has demonstrated remarkable efficacy for therapy of lower-risk myelodysplastic syndromes (MDS) associated with 5q(-). The present evaluation aimed to describe the characteristics and outcomes of low-risk MDS patients treated with lenalidomide in Austria. PATIENTS AND METHODS: For this retrospective, multicenter, observational analysis of MDS patients who received lenalidomide, data were collected at various hospitals in Austria over a period of 3 years. MDS classification, previous and current MDS therapies, and outcome and safety of lenalidomide were evaluated. RESULTS: Forty-six percent of the patients (n = 23) had a 5q(-) syndrome, while 12% (n = 6) exhibited 5q(-) plus additional aberrations or isolated 5q(-) but ≥ 5% blasts in the bone marrow (10%, n = 5). The remaining 32% of patients (n = 16) had MDS with other World Health Organization classifications. Seventy percent belonged to lower International Prognostic Scoring System risk classes. Sixteen centers participated, involving a total of 50 patients. Most frequently used lenalidomide doses were 10 mg and 5 mg on days 1 to 21 of a 28-day cycle. Seventy-five percent of the patients received 11 months of treatment, with a median therapy period of 3.5 months; median follow-up was 3.9 months (range, 0-26 months). Response rate, defined as transfusion independence during the 2 months after lenalidomide therapy, was 64%. Median overall survival was not reached. CONCLUSION: Lenalidomide was well tolerated and is an effective and well-tolerated option for therapy of patients with 5q(-) syndrome but also lower-risk MDS patients with other World Health Organization classifications in clinical practice.