Dosimetry of conformal dynamic arc radiotherapy and intensity modulated radiotherapy in unresectable cholangiocarcinoma

Background: Radiotherapy in cholangiocrcinoma has to overcome organ tolerance of the upper abdomen. Hi-technology radiotherapy may improve conformity and reduce dose to those organ. Objective: Quantitatively compare the dosimetry of conformal dynamic arc radiotherapy (CD-arcRT) and intensity modulated radiotherapy (IMRT) in unresectable cholangiocarcinoma. Material and methods: Eleven cases of unresectable cholangiocarcinoma were re-planned with IMRT and CDarcRT at King Chulalongkhorn Memorial Hospital between 20 September 2004 and 31 December 2005. Both the planning techniques were evaluated using the dose volume histogram of the planning target volume and organ at risk. The conformation number and dose to critical normal structures were used to determine the techniques. Results: IMRT technique was significantly conformed to the planning target volume than CD-arcRT in term of conformation number. For critical structure, IMRT significantly reduced the radiation dose to liver in terms of mean liver dose, V30Gy and V20Gy of the right kidney. Conclusion: The advantage of IMRT was more conformity and reduced dose to critical structure compared with CD-arcRT, but there was no difference between these techniques in terms of V20Gy of left kidney and maximum dose to the spinal cord.

Intracranial germ cell tumors: experience in King Chulalongkorn Memorial Hospital.

A retrospective study was performed on 69 patients with intracranial germ cell tumors who were treated at the Division of Radiation Oncology, Department of Radiology, King Chulalongkorn Memorial Hospital from 1990 to 2000. Median age was 15 years. Forty-two cases (60.87%) had histologically confirmed germinoma or nongerminomatous germ cell tumors. Germinoma was the predominate histology followed by mixed germ cell tumors. Pineal and suprasellar regions were the two leading sites, hydrocephalus (85.5%) and diplopia (57.97%) were the two most common clinical presentations. Only 13 cases had the result of cerebrospinal fluid (CSF) cytology or magnetic resonance imagine (MRI) of the spine before initial treatment. Serum tumor markers, Alpha fetoprotein and beta-human chorionic gonadotropin, were available in 66.67 per cent. Total or partial tumor removal were feasible in 24 cases. Whole brain irradiation was given in almost all cases with the median dose of 3,600 cGy. The median total tumor dose was 5,400 cGy. Whole spine radiation was utilized in 17 cases. The mean follow-up time was 41 months. The five-year disease free survival was 73.59 per cent. Overall 3 and 5 year survival rates were 86.45 per cent and 81.64 per cent, respectively.

Results of radiation therapy in stage 1B cervical carcinoma at King Chulalongkorn Memorial Hospital: fifteen-year experience.

A retrospective study was performed on 131 patients with stage 1B cervical carcinoma who were referred and treated with external beam radiation and intracavitary brachytherapy at the Division of Radiation Therapy, Department of Radiology, King Chulalongkorn Memorial Hospital between February 1985 and February 2000. Primary outcomes were overall survival rate, progression free survival rate, recurrence, and treatment-related complications. The treatment results from different sources of intracavitary radiation therapy were secondary endpoints. The number of patients treated with Ra-226, Cs-137, and Ir-192 intracavitary irradiation were 12, 84, and 35 patients respectively. The median follow-up times were 69, 59, and 21 months for Ra-226, Cs-137, and Ir-192, respectively. Actuarial 5-year overall survival rate was 89 per cent. The 5-year progression free survival rate was 80 per cent. Actuarial 5-year survival and progression free survival rate were comparable among different sources of intracavitary brachytherapy (p = 0.553 and p=0.793, respectively). The overall recurrent rate was 16.8 per cent. Of the recurrence; 40.9 per cent was locoregional, 54.6 per cent was distant failure, and 4.5 per cent was combined locoregional and distant failure. The overall complication rate was 25.95 per cent. The severe complication rates (Grade III-V) from treatment occurred in the urinary bladder (0.76%) and in the small bowel (0.76%.) These results suggest that radiation therapy alone is an effective treatment for stage 1B cervical carcinoma. Additionally, all types of intracavitary brachytherapy provide comparable clinical results.