The Journal of The Korean Society for Therapeutic Radiology and Oncology 

About: The Journal of The Korean Society for Therapeutic Radiology and Oncology is an academic journal. The journal publishes majorly in the area(s): Radiation therapy & Breast cancer. Over the lifetime, 230 publications have been published receiving 723 citations.

Dose Response Relationship in Local Radiotherapy for Hepatocellular Carcinoma.

Abstract: PURPOSE Dose escalation using three-dimensional conformal radiotherapy (3D-CRT) is based on the hypothesis that increasing the dose can enhance tumor control. This study aimed to determine whether a dose-response relationship exists in local radiotherapy for primary hepatocellular carcinoma (HCC). METHODS AND MATERIALS One hundred fifty-eight patients were enrolled in the present study between January 1992 and March 2000. The exclusion criteria included the presence of an extrahepatic metastasis, liver cirrhosis of Child class C, tumors occupying more than two-thirds of the entire liver, and a performance status on the Eastern Cooperative Oncology Group scale of more than 3. Radiotherapy was given to the field, including the tumor, with generous margin using 6- or 10-MV X-rays. The mean radiation dose was 48.2 +/- 7.9 Gy in daily 1.8-Gy fractions. The tumor response was assessed based on diagnostic radiologic examinations, including a computed tomography scan, magnetic resonance imaging, and hepatic artery angiography 4-8 weeks after the completion of treatment. Liver toxicity and gastrointestinal complications were evaluated. RESULTS An objective response was observed in 106 of 158 (67.1%) patients. Statistical analysis revealed that the total dose was the most significant factor associated with the tumor response. The response rates in patients treated with doses <40 Gy, 40-50 Gy, and >50 Gy were 29.2%, 68.6%, and 77.1%, respectively. Survivals at 1 and 2 years after radiotherapy were 41.8% and 19.9%, respectively, with a median survival time of 10 months. The rate of liver toxicity according to the doses <40 Gy, 40-50 Gy, and >50 Gy was 4.2%, 5.9%, and 8.4%, respectively, and the rate of gastrointestinal complications was 4.2%, 9.9%, and 13.2%, respectively. CONCLUSIONS The present study showed the existence of a dose-response relationship in local radiotherapy for primary HCC. Only the radiation dose was a significant factor for predicting an objective response. The results of this study showed that 3D-CRT can theoretically be used for treating primary HCC.

Film Dosimetry for Intensity Modulated Radiation Therapy: Dosimetric Evaluation.

Abstract: X-ray film has been used for the dosimetry of intensity modulated radiation therapy (IMRT). However, the over-response of the film to low-energy photons is a significant problem in photon beam dosimetry, especially in regions outside penumbra. In IMRT, the radiation field consists of multiple small fields and their outside-penumbra regions; thus, the film dosimetry, for it involves the source of over-response in its radiation field. In this study we aim to verify and possibly improve film dosimetry for IMRT. Two types of modulated beams were constructed by combining five to seven different static radiation fields using 6 MV x rays. For verifying film dosimetry, x-ray films and an ion chamber were used to measure dose profiles at various depths in a phantom. The film setups include both parallel and perpendicular arrangements against the beam incident direction. In addition, to reduce an over-response, we placed 0.01 in. (0.25 mm) thick lead filters on both sides of the film. Compared with ion-chamber measurement, measured dose profiles showed the film over-response at outside-penumbra and low-dose regions. The error increased with depths and approached 15% as a maximum for the field size of 15 cm x 15 cm at 10 cm depth. The use of filters reduced the error down to 3%. In this study we demonstrated that film dosimetry for IMRT involves sources of error due to its over-response to low-energy photons, with the error most transparent in the low-dose region. The use of filters could enhance the accuracy in film dosimetry for IMRT. In this regard, the use of an optimal filter condition is recommended.

Enhancement of Tumor Radioresponse by Combined Chemotherapy in Murine Hepatocarcinoma.

Abstract: Background and Aims: Recent studies have shown that local radiotherapy can be an effective component of the treatment for hepatocellular carcinoma. To further improve therapeutic efficacy, use of drugs that can beneficially interact with radiation has been suggested. The purpose of this study was to identify drugs that can enhance radioresponse of murine hepatocarcinoma. Methods: C3H/HeJ mice bearing 8 mm tumors of murine hepatocarcinoma, HCa-I, were treated with 25 Gy radiation and one of the following drugs: 5-Fu, 150 mg/kg; adriamycin, 8 mg/kg; cisplatin, 6 mg/kg; paclitaxel, 40 mg/kg; and gemcitabine, 50 mg/kg. Tumor response to the treatment was determined by the use of a tumor growth delay assay and by an enhancement factor. The apoptotic level was assessed in tissue sections. The expression of regulating molecules was analyzed by using western blotting for p53, Bcl-2, Bax, Bcl-XL, Bcl-XS, and p21WAF1/CIP1. Results: Among the drugs tested, only gemcitabine enhanced the antitumor effect of radiation, with an enhancement factor of 1.6. The induction of apoptosis by a combination of gemcitabine and radiation was shown as only an additive level. In the analysis of radiation-induced expression of regulating molecules, the most significant change by combining gemcitabine with radiation was the activation of p21WAF1/CIP1. Conclusion: Gemcitabine is the first to show an enhancement of radioresponse of murine hepatocarcinoma when combined with radiation. The key element of enhancement is thought to be p21WAF1/CIP1.