Recent developments in radiotherapy for hepatocellular carcinoma

The role of radiotherapy in practice is mainly palliative. According to the Practice Guidelines for Management of Hepatocellular Carcinoma (2009) developed by the Korean Liver Cancer Study Group and the National Cancer Center, Korea, radiotherapy can be applied for 1) refractoriness to trans-catheter hepatic arterial chemo-embolization, 2) portal vein tumor thrombosis, and 3) palliative therapy to reduce the symptoms caused by hepatocellular carcinoma. Radiotherapy is one of the most rapidly developing fields of medical research. Recent advances in intensity-modulated radiotherapy, image-guided radiotherapy, and respiratory-gated radiotherapy technologies have enabled more accurate and precise radiation delivery for the treatment of hepatocellular carcinoma. Proton therapy is also emerging as a candidate therapy for ablative measures for patients ineligible for other curative local therapies. Due to recent advances in radiotherapy technologies, radiotherapy for hepatocellular carcinoma has been evolving into stereotactic ablative radiotherapy, which delivers an ablative dose of radiation in 1 to 4 sessions. Clinical series have confirmed that it is safe in Child-Pugh A patients and local control is sustained. The possibility for performing phase 3 randomized clinical trials involving the radiotherapy modality has increased with those advances. Not merely palliative, the role of radiotherapy in the treatment of hepatocellular carcinoma will be expanded to potentially curative therapy in patients who are ineligible for other curative local therapies.

Evaluation of Difference between Skin Motion and Tumor Motion for Respiration Gated Radiotherapy / 의학물리

Accounting for tumor motion in treatment planning and delivery is one of the most recent and significant challenges facing radiotherapy. The purpose of this study was to investigate the correlation and clarified the relationship between the motion of an external marker using the Real?Time Position Management (RPM) System and an internal organ motion signal obtained fluoroscope. We enrolled 10 patients with locally advanced lung cancer and liver cancer, retrospectively. The external marker was a plastic box, which is part of the RPM used to track the patient's respiration. We investigated the quantitatively correlation between the motions of an external marker with RPM and internal motion with fluoroscope. The internal fiducial motion is predominant in the caraniocaudal direction, with a range of 1.3~3.5 cm with fluoroscopic unit. The external fiducial motion is predominant in the caraniocaudal direction, with a range of 0.43~2.19 cm with RPM gating. The two measurements ratio is from 1.31 to 5.56. When the regularization guided standard deviation is from 0.08 to 0.87, mean 0.204 cm, except only for patients #3 separated by a mean 0.13 cm, maximum of 0.23 cm. This result is a good correlation between internal tumor motion imaged by fluoroscopic unit and external marker motion with RPM during expiration within 0.23 cm. We have demonstrated that gating may be best performed but special attention should be paid to gating for patients whose fiducials do not move in synchrony, because targeting on the correct phase difference alone would not guarantee that the entire tumor volume is within the treatment field.