Ihl Bohng Choi

Stereotactic body radiation therapy with or without transarterial chemoembolization for patients with primary hepatocellular carcinoma: preliminary analysis

BackgroundThe objectives of this retrospective study was to evaluate the efficacy of stereotactic body radiation therapy (SBRT) for small non-resectable hepatocellular carcinoma (HCC) and SBRT combined with transarterial chemoembolization (TACE) for advanced HCC with portal vein tumor thrombosis (PVTT).MethodsThirty one patients with HCC who were treated with SBRT were used for the study. We studied 32 HCC lesions, where 23 lesions (22 patients) were treated targeting small non-resectable primary HCC, and 9 lesions (9 patients) targeting PVTT using the Cyberknife. All the 9 patients targeting PVTT received TACE for the advanced HCC. Tumor volume was 3.6–57.3 cc (median, 25.2 cc) and SBRT dose was 30–39 Gy (median, 36 Gy) in 3 fractions for consecutive days for 70–85% of the planned target volume.ResultsThe median follow up was 10.5 months. The overall response rate was 71.9% [small HCC: 82.6% (19/23), advanced HCC with PVTT: 44.4% (4/9)], with the complete and partial response rates of 31.3% [small HCC: 26.1% (6/23), advanced HCC with PVTT: 11.1% (1/9)], and 50.0% [small HCC: 56.5% (13/23), advanced HCC with PVTT: 33.3% (3/9)], respectively. The median survival period of small HCC and advanced HCC with PVTT patients was 12 months and 8 months, respectively. No patient experienced Grade 4 toxicity.ConclusionSBRT for small HCC and SBRT combined with TACE for advanced HCC with PVTT showed feasible treatment modalities with minimal side effects in selected patients with primary HCC.

STEREOTACTIC BODY RADIOTHERAPY FOR PATIENTS WITH UNRESECTABLE PRIMARY HEPATOCELLULAR CARCINOMA: DOSE-VOLUMETRIC PARAMETERS PREDICTING THE HEPATIC COMPLICATION

PURPOSE To identify the parameters that predict hepatic toxicity and deterioration of hepatic function. MATERIALS AND METHODS A total of 47 patients with small unresectable primary hepatocellular carcinoma received hypofractionated stereotactic body radiotherapy (SBRT) using the CyberKnife. Of those, 36 patients received no other local treatments that could influence hepatic toxicity at least for 3 months after the completion of SBRT. The gross tumor volume (GTV) was 18.3 ± 15.9 cm(3) (range, 3.0-81.3 cm(3)), and the total dose administered was 30-39 Gy (median, 36 Gy). To assess the deterioration of hepatic function, we evaluated the presence or absence of the progression of Child-Pugh class (CP class). To identify the parameters of predicting the radiation-induced hepatic toxicity and deterioration of the hepatic function, several clinical and dose-volumetric parameters were evaluated. RESULTS Of 36 patients, 12 (33%) developed Grade 2 or higher hepatic toxicity and 4 (11%) developed progression of CP class. The multivariate analysis showed that the only significant parameter associated with the progression of CP class was the total liver volume receiving a dose less than 18 Gy (<18 Gy). CONCLUSIONS The progression of CP class after SBRT limits other additional local treatments and also reflects the deterioration of hepatic function. Therefore, it would be important to note that the presence or absence of the progression of CP class is a dose-limiting factor. The total liver volume receiving <18 Gy should be greater than 800 cm(3) to reduce the risk of the deterioration of hepatic function.

Primary radiation therapy in patients with localized orbital marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT Lymphoma).

PURPOSE To evaluate the outcomes of patients with localized orbital marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT lymphoma) who were treated with radiotherapy (RT). METHODS AND MATERIALS We retrospectively reviewed the records of 46 patients who were treated with RT for pathologically confirmed localized stage IE marginal zone B-cell lymphoma of MALT. The radiation dose ranged from 21.6 to 45 Gy (median, 30.6 Gy) at 1.8-2.0 Gy per fraction. Median follow-up duration was 32.3 months (range, 3.1-113.6 months). RESULTS Forty-three patients (93%) achieved complete remission (CR), and three patients (7%) achieved partial remission (PR). Five-year relapse-free survival, cause-specific survival, and overall survival were 93%, 100%, and 100%, respectively. Among the patients with CR, two had recurrence at three sites. One patient relapsed locally and was successfully salvaged with reirradiation. The other patient relapsed in a distant site and was successfully treated with six cycles of CHOP chemotherapy. Late complications were noted in four patients. Two patients developed cataracts at 26 and 37 months after completion of RT. The other two patients developed nasolacrimal duct obstructions at 4 and 11 months after completion of RT. CONCLUSION Our study showed that a modest dose of RT is an excellent treatment modality with low complication and recurrence rates. We suggest that a dose of 30.6 Gy is tolerable and sufficient for treating orbital MALT lymphoma. Even following recurrence, successful salvage is possible with RT or chemotherapy.

Evaluation of the Accuracy of the CyberKnife

The use of stereotactic radiosurgical systems to treat intracranial and extracranial tumors and other lesions requires a high degree of accuracy in target identification and localization. CyberKnife can deliver, with a high degree of precision, a single or several fractions of radiation dose to a well-defined small intracranial or extracranial target. The accuracy of the output factor directly affects the accuracy of dose delivery in CyberKnife system. The purpose of this study was to evaluation the total system accuracy of the CyberKnife and also to estimate an output factor for CyberKnife using the several detectors. Accuracy of target localization was measured in anthropomorphic head phantom containing a spherical target, fiducial markers, and two pieces of film. The accuracy measured is the displacement of the dose contours from the treatment plan to that measured in the exposed phantom. All measurements of the output factors for collimators were performed by six different detectors: diode detector, X-Omat V film, Gafchromic EBT film, 0.015, 0.125 and 0.6 cc ionization chamber. Each collimator normalized with respect to the output factor of the largest collimator. We performed the E2E test and the general film dosimetry for estimation target localization in CyberKnife. The targeting error of the skull tracking mode and fiducial tracking mode were 0.956 mm and 0.923 mm. We could confirm the accuracy of total system is less than the 1 mm. For larger collimators, the output factors from six detectors showed a good agreement. For the collimators less than 15 mm, there were substantial differences in the output factors among different detectors. That is, the value of output factor for the 5 mm collimator of a diode and Gafchromic film was each 0.656 and 0.777. The Gafchromic EBT film was considered more accurate than the others detectors.