Clinical experience in pediatric neuroblastoma intensity modulated radiotherapy.

BACKGROUND: In spite of the numerous publications of dosimetric comparison of intensity modulated radiotherapy (IMRT) versus conventional radiotherapy in pediatrics, few data exist regarding the clinical use of IMRT and its potential late effects. PROCEDURE: Pediatric neuroblastoma patients treated between November 2008 and October 2010 with IMRT were reviewed. Treatment plans, clinical, laboratory and radiological data at the last follow up date were evaluated. RESULTS: Thirteen patients received IMRT. The mean age was 4.9 ± 2 years. The radiation dose ranged from 21 to 25.5 Gy with a mean dose of 24.06 Gy. The mean liver dose was 9.81 Gy. The V8 of the liver was 51 ± 20%, and the V15 of the liver was 21 ± 12%. V18 of the right and left kidneys were 32 ± 27% and 23 ± 18% respectively. The minimum and maximum vertebral point doses were 12.82 and 24.87 Gy respectively. The IMRT treatment was well tolerated in terms of acute toxicity. At 26 month follow up, second malignancy and skeletal asymmetry were not noted, and the liver and the kidney functions showed no significant abnormalities. CONCLUSIONS: The use of IMRT in pediatric neuroblastoma confers higher target conformality with better sparing of the kidneys and it did not show any considerable short term side effects.

Cone beam CT for organs motion evaluation in pediatric abdominal neuroblastoma.

BACKGROUND AND PURPOSE: To quantify the organ motion relative to bone in different breathing states in pediatric neuroblastoma using cone beam CT (CBCT) for better definition of the planning margins during abdominal IMRT. METHODS AND MATERIALS: Forty-two datasets of kV CBCT for 9 pediatric patients with abdominal neuroblastoma treated with IMRT were evaluated. Organs positions on planning CT scan were considered the reference position against which organs and target motions were evaluated. The position of the kidneys and the liver was assessed in all scans. The target movement was evaluated in four patients who were treated for gross residual disease. RESULTS: The mean age of the patients was 4.1 ± 1.6 years. The range of target movement in the craniocaudal direction (CC) was 5mm. In the CC direction, the range of movement was 10mm for the right kidney, and 8mm for the left kidney. Similarly, the liver upper edge range of motion was 11 mm while the lower edge range of motion was 13 mm. CONCLUSIONS: With the use of daily CBCT we may be able to reduce the PTV margin. If CBCT is not used daily, a wider margin is needed.

Palliative spleen irradiation: can we standardize its technique?

PURPOSE: To explore the pattern of practice of palliative splenic irradiation (PSI) at the National Cancer Institute (NCI), Cairo University. PATIENTS AND METHODS: The medical records of patients referred for PSI during the time period from 1990 to 2005 were retrospectively reviewed. We compared the three most common planning techniques (two parallel opposing, single direct field, anterior and lateral fields). RESULTS: Eighteen patients who received PSI were identified. Thirteen patients were diagnosed as CML and 5 as CLL. The mean age of the patients was 44 (+/-16) years and the majority were men (60%). Spleen enlargement was documented in all cases. The single direct anterior field was the most commonly used technique. The dose per fraction ranged from 25 cGy to 100 cGy. The total dose ranged from 125 cGy to 1200 cGy and the median was 200 cGy (mean 327 cGy). There was no significant difference between CML and CLL patients regarding the dose level. Three out of 5 CLL patients and only one out of 13 CML patients received re-irradiation. All patients showed subjective improvement regarding pain and swelling. There was a significant increase in the hemoglobin level and a significant decrease in the WBC count. The single direct field shows variations in the dose from 56 to 102%; however, it is the simplest and the best regarding the dose to the surrounding normal tissues especially the kidney and the liver. CONCLUSION: PSI has a significant palliative benefit. Although the most widely accepted technique is the 2 parallel opposing anterior-posterior fields, single anterior field is also considered as a suitable option. Higher doses are needed for CLL patients compared to CML patients.