Dong Han Lee

Stereotactic body radiation therapy for inoperable hepatocellular carcinoma as a local salvage treatment after incomplete transarterial chemoembolization

The objective of this study was to evaluate the efficacy and safety of stereotactic body radiation therapy (SBRT) as a local salvage treatment after incomplete transarterial chemoembolization (TACE) for inoperable hepatocellular carcinoma (HCC).

Preliminary result of stereotactic body radiotherapy as a local salvage treatment for inoperable hepatocellular carcinoma.

To evaluate the toxicity and efficacy of stereotactic body radiotherapy (SBRT) for the treatment of localized hepatocellular carcinoma (HCC) in the absence of another standard treatment option.

Image-Guided Stereotactic Body Radiation Therapy in Patients With Isolated Para-Aortic Lymph Node Metastases From Uterine Cervical and Corpus Cancer

PURPOSE The aims of this study were to evaluate the role of stereotactic body radiation therapy (SBRT) as a local treatment for isolated para-aortic lymph node (PALN) metastases originating from uterine cervical and corpus cancer. METHODS AND MATERIALS We retrospectively enrolled 30 patients with isolated PALN metastases originating from uterine cervical and corpus cancer who had received SBRT using the CyberKnife (CK). All patients were shown to have isolated PALN metastases by computed tomography (CT) and/or positron emission tomography (PET)-CT. The overall survival (OS), local control (LC) rate, and disease progression-free survival (DPFS) rate were calculated according to the Kaplan-Meier method. Comparison between prognosis groups was performed using log-rank analysis. Toxicities were also evaluated. RESULTS The 4-year OS rate was 50.1%, and the median survival time was not reached. The OS rate among symptomatic patients was significantly lower than that among asymptomatic patients (p = 0.002). The 4-year actuarial LC rate was 67.4%. Patients with a planning target volume of </=17 ml had significantly higher LC rates (p = 0.009). The 4-year DPFS rate was 45.0%, and the median time to disease progression was 32 months. Small planning target volume was a favorable prognostic factor (p = 0.043). Grade 3 or 4 complications requiring hospitalization were reported in 1 patient at 20 months after SBRT. CONCLUSION The OS and LS rates were promising, and the incidence of toxicities was low. Use of SBRT with the CyberKnife is an effective modality for treating isolated PALN metastases in patients with uterine cervical and corpus cancer.

High-dose stereotactic body radiotherapy correlates increased local control and overall survival in patients with inoperable hepatocellular carcinoma

BackgroundRecent studies using stereotactic body radiotherapy (SBRT) for hepatocellular carcinoma (HCC) have reported high tumor response and local control. However, the optimal SBRT dose remains unknown, and it is still not clear whether a dose response relationship for local control (LC) and overall survival (OS) exist or not. We performed this study to determine whether a dose response relationship for LC and OS is observed in SBRT for inoperable HCC.MethodsBetween 2003 and 2011, 108 patients with HCC were treated with SBRT. All patients were unsuitable for surgery or local ablation and had incomplete response to transarterial chemoembolization. Eighty-two patients with a longest tumor diameter (LD) less than or equal to 7.0 cm who were treated with 3-fraction SBRT and were analyzed. This cohort comprised 74 Child-Turcotte-Pugh (CTP) class A patients and 8 CTP class B7 patients. The median LD was 3.0 cm (range, 1.0–7.0 cm), and the median dose was 51 Gy (range, 33–60 Gy).ResultsLC and OS rates at 2 years after SBRT were 87% and 63%, respectively, with a median follow-up duration of 30 months for all patients. The 2-year LC/OS rates for patients treated with doses of > 54, 45–54, and < 45 Gy were 100/71, 78/64, and 64%/30%, respectively (p = .009/p < .001). Multivariate analysis revealed that the SBRT dose (p = .005) and Barcelona Clinic Liver Cancer stage (p = .015) were significant prognostic factors for OS. Correlation analysis revealed a positive linear relationship between the SBRT dose and LC (p = .006, R = .899)/OS (p = .002, R = .940) at 2 years. Based on the tumor-control probability model, a dose of 54.8 Gy provides 2-year LC with a 90% probability. Five patients experienced grade 3 or higher gastrointestinal toxicity, and 6 had deteriorating of CTP score by greater than or equal to 2 within 3 months of SBRT.ConclusionsThis study demonstrated a dose response relationship for LC and OS with SBRT for HCC. Higher LC rates resulting from an increased dose may translate into survival benefits for patients with HCC.

Stereotactic Body Radiation Therapy Using Three Fractions for Isolated Lung Recurrence from Colorectal Cancer

Objective: To determine the feasibility of stereotactic body radiotherapy (SBRT) using 3 fractions for isolated colorectal lung metastases. Methods: From June 2003 to December 2006, 13 cases of isolated pulmonary metastasis from colorectal cancer were treated by SBRT due to an inoperable state (7 patients), or the patient’s refusal to undergo surgical excision (6 patients). All patients underwent chemotherapy for salvage treatment. SBRT doses ranged from 39 to 51 Gy in 3 fractions. Nine patients had a solitary lesion, 3 patients had 2 lesions, and 1 patient had 3 lesions. Median tumor volume for the 18 lesions was 5.9 ml (range 1.6–45 ml). Results: Follow-up duration was 15–57 months. Three-year overall survival, local control and progression-free survival rates were 64.7, 52.7 and 11.5%, respectively.Univariate analysis showed that total internal target volume was a significant prognostic factor for local control. During the follow-up, 11 of the 13 patients experienced local recurrence, distant metastasis or both. The most frequent site of failure was in a nontargeted lung region. No severe complication was attributed to SBRT. Conclusion: Our study suggests the potential feasibility of SBRT for selected patients with 1–3 small metastatic nodules. A further larger-scale study is required to define the indications for SBRT in cases with isolated pulmonary metastasis from colorectal cancer.

Hypofractionated Stereotactic Radiation Therapy for Skull Base and Upper Cervical Chordoma and Chondrosarcoma: Preliminary Results

Introduction: Chordoma and chondrosarcoma are rare tumors of the base of the skull and are difficult candidates for surgical treatment. They are also usually resistant to conventional radiation therapy. We report preliminary results of hypofractionated stereotactic radia- tion therapy (SRT) using the Cyberknife system (Accuray Inc., Sunnyvale, Calif., USA) for primary and recurrent chordomas and chondrosarcomas of the skull base and upper cervical region. Material and Methods: Nine pathologically proven chordoma/chondrosarcoma patients underwent Cyberknife treatment, and in 4 patients Cyberknife was performed as a primary adjuvant treatment after operation. Remainder of the patients had previously received conventional radiotherapy except 1 who had received Gamma Knife treatment. The prescribed tumor dose ranged from 21 to 43.6 Gy in three to five fractions. The dosimetric characteristics were evaluated for conformity and coverage indices. Dose volume histograms of both the tumor and the critical structure were obtained, and the dose delivered to a specific volume (25, 50 and 100%) of the critical structure was calculated in each case. Mass response was measured on follow-up MRI scans. Total tumor doses of different fractionation numbers were converted into single session equivalent doses and linear quadratic equivalent doses of conventional radiation for comparison among patient groups. Result: Nosignificant complications were observed during the treatment and early follow-up periods except one instance of transient esophagitis and one instance of otitis. All treatment plans met the criteria for standard protocol of radiosurgery suggested by the Radiation Therapy Oncology Group, specifically in terms of conformity index, which ranged from 1.01 to 1.83. Three plans had a coverage index that was rated as a minor acceptable deviation. All patients were followed from 11 to 30 (median 24) months following the treatment with regular magnetic resonance images, and 4 patients showed mass reduction. Disease progression was not noted in any patient during the above follow-up period except 1 patient who showed asymptomatic recurrence on 27-month follow-up MRI. Dose volume histograms revealed that the relative dose to volume percent of critical structure, measured at 25, 50 and 100%, was apparently lower in the pretreatment surgical decompression group than in the nondecompression group. Two patients developed radiation-induced myelopathy. The delivered radiation dose to the critical structure calculated using the linear-quadratic formula was within the acceptable range in one case and exceeded 70 Gy at 50% volume of the spinal cord in the other. Conclusion: The hypofractionated Cyberknife SRT is effective in generating therapeutic response in these radioresistant tumors, with minimal toxicity during the procedure and early follow-up period. Repeated radiosurgical treatment may also be feasible for tumor recurrences but deserves great caution with respect to the biological effects of the accumulated dose on the adjacent critical structures. Cyberknife SRT may be a potentially valuable treatment option once the long-term results and appropriate dose calculators are optimally defined.

Image-guided stereotactic body radiation therapy for localized prostate cancer.

PURPOSE We report the results of a retrospective study of stereotactic body radiation therapy (SBRT) using CyberKnife for localized prostate cancer. The study focused on the safety and feasibility of this treatment modality. MATERIALS AND METHODS Between October 2002 and December 2007, 44 patients suffering from localized adenocarcinoma of the prostate were treated with SBRT using CyberKnife at the Korea Cancer Center Hospital. The patients were divided into 3 groups: a low-risk group (5 patients), an intermediate-risk group (10 patients), and a high-risk group (29 patients). Five patients received 32 Gy in 4 fractions, 28 patients received 34 Gy in 4 fractions, and 11 patients received 36 Gy in 4 fractions. RESULTS The median age of the patients was 69 years (range, 53-79 years) and the median duration of follow-up 40 months (range, 12-78 months). There were 6 acute and 3 late grade 2 urinary toxicities, and 4 acute and 5 late grade 2 rectal toxicities, but there were no grade 3 or higher treatment-related toxicities. The 5-year cause-specific survival rate and progression-free survival rate were both 100%. At last follow-up, the biochemical failure-free rate of the low-risk, intermediate-risk and high-risk patients was 100%, 100% and 90.8%, respectively. CONCLUSION SBRT using CyberKnife for localized prostate cancer is safe and well tolerated. We obtained promising results with 34 Gy in a 4-fraction regimen especially for the high-risk patients.

Local tumor control after retreatment of spinal metastasis using stereotactic body radiotherapy; comparison with initial treatment group

Abstract Background. The aim of this study is to evaluate local control rates after stereotactic body radiotherapy (SBRT) in recurrent spinal metastasis after external beam radiotherapy (EBRT) and new spinal metastatic lesions. Material and methods. Retrospective review of medical records and radiological data was performed on 54 retreatment and 131 initial SBRT patients. To compare various fractionation schedules, the biologically effective dose (BED) was applied. SBRT dose was calculated with linear-quadratic model and normalized to a 2-Gy equivalent dose (nBED, α/β =2 Gy for spinal cord, α/β =10 Gy for tumor). Doses to a point within the spinal cord that received the maximum dose (Pmax) were checked. Local control failure was defined as progression by imaging study. Overall survival, progression free survival, delivered radiation dose to tumor and spinal cord, and spinal cord Pmax nBED were compared in two groups. Results. The mean delivered radiation doses to tumor margin during SBRT were 51.1 Gy2/10 (retreatment) and 50.7 Gy2/10 (initial treatment). Mean survival was 29.6 months (overall)/20.7 months (retreatment)/ 32.4 months (initial treatment). Mean progression free period was 23.9 months (overall)/18.0 months (retreatment)/ 26.0 months (initial treatment). Radiological control rates of retreatment and initial treatment group were 96%/95% at six months, 81%/89% at 12 months and 79%/90% at 24 months. Among 54 retreatment lesions, 13 lesions showed local control failure during follow-up. With regard to spinal cord radiation dose during SBRT, Spinal cord Pmax nBED was 46.2 Gy2/2 (retreatment) and 48.7 Gy2/2 (initial treatment). In retreatment group, total nBED to spinal cord was a mean of 83.4 Gy2/2. There was no case of radiation myelopathy detected. Conclusions. Retreatment of spinal metastases using SBRT provided effective local control without neurological complications.

Stereotactic body radiotherapy for isolated para-aortic lymph node recurrence after curative resection in gastric cancer.

The aim of this study was to investigate whether stereotactic body radiotherapy (SBRT) can salvage gastric cancer patients with para-aortic lymph node (PALN) recurrence. From January 2003 to December 2006, 7 patients were treated for isolated PALN recurrence from gastric cancer after curative resection. Follow up durations ranged from 19 to 33 months (median; 26 months), and SBRT doses from 45 Gy to 51 Gy (median 48 Gy) in 3 fractions. Disease progression-free and overall survivals and toxicities were recorded. Response to treatment was assessed by computed tomography. Final patient outcomes were as follows: 2 were alive without evidence of disease, 3 remained alive with disease, and 2 patients died of disease. Five of 7 patients showed complete response and 2 patients partial response between 3 and 11 months after SBRT. Three-year overall and disease progression-free survival rates post-SBRT were 43% and 29%, respectively. No severe complication was detected during follow-up. Selected patients with isolated PALN recurrence can be salvaged by SBRT without severe complications.

Predictor of Severe Gastroduodenal Toxicity After Stereotactic Body Radiotherapy for Abdominopelvic Malignancies

PURPOSE To identify the predictors for the development of severe gastroduodenal toxicity (GDT) in patients treated with stereotactic body radiotherapy (SBRT) using 3 fractionations for abdominopelvic malignancies. METHODS AND MATERIALS From 2001 to 2011, 202 patients with abdominopelvic malignancies were treated with curative-intent SBRT. Among these patients, we retrospectively reviewed the clinical records of 40 patients with the eligibility criteria as follows: 3 fractionations, follow-up period≥1 year, absence of previous radiation therapy (RT) history or combination of external-beam RT and the presence of gastroduodenum (GD) that received a dose higher than 20% of prescribed dose. The median SBRT dose was 45 Gy (range, 33-60 Gy) with 3 fractions. We analyzed the clinical and dosimetric parameters, including multiple dose-volume histogram endpoints: V20 (volume of GD that received 20 Gy), V25, V30, V35, and Dmax (the maximum point dose). The grade of GDT was defined by the National Cancer Institute Common Toxicity Criteria version 4.0, and GDT≥grade 3 was defined as severe GDT. RESULTS The median time to the development of severe GDT was 6 months (range, 3-12 months). Severe GDT was found in 6 patients (15%). Dmax was the best dosimetric predictor for severe GDT. Dmax of 35 Gy and 38 Gy were respectively associated with a 5% and 10% probability of the development of severe GDT. A history of ulcer before SBRT was the best clinical predictor on univariate analysis (P=.0001). CONCLUSIONS We suggest that Dmax is a valuable predictor of severe GDT after SBRT using 3 fractionations for abdominopelvic malignancies. A history of ulcer before SBRT should be carefully considered as a clinical predictor, especially in patients who receive a high dose to GD.