Clinical utilization of radiation therapy in Korea between 2017 and 2019

Purpose@#This study aimed to evaluate the clinical infrastructure and utilization of radiotherapy (RT) services in Korea between 2017 and 2019. @*Materials and Methods@#We extracted the data of patients who underwent RT between 2017 and 2019 from the Health Insurance Review and Assessment Service. We further analyzed this data according to the diagnosis and treatment modalities of patients diagnosed with International Classification of Disease 10 (ICD-10) diagnostic codes C00–C97 and D00–D48. In addition, we collected statistics on RT facilities in Korea using a nationwide survey. @*Results@#The total number of patients who received RT in 2017, 2018, and 2019 were 77,901, 81,849, and 87,460, respectively. The number of patients diagnosed with ICD 10 C- and D-codes in 2019 was 86,339, of whom 39,467 were men and 46,872 women. The rate of utilization of RT among cancer patients was 30.4% in 2017 and 2018 and 30.9% in 2019. In 2019, the most common types of cancers treated with RT were breast, lung, prostate, colorectal, and liver cancers. Regarding the RT infrastructure in Korea, there were 95 radiation oncology centers, 237 megavoltage (MV) teletherapy units, 35 brachytherapy units, and two proton accelerators in 2019. There were 4.5 MV teletherapy machines per million. @*Conclusion@#The number of patients treated with RT has increased consistently from 2017 to 2019. As the number of patients with cancer increases, it is expected that the RT infrastructure will be further expanded in Korea.

The Clinical Utilization of Radiation Therapy in Korea between 2011 and 2015 / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The purpose of this study was to estimate the clinical utilization of radiation therapy (RT) in Korea between 2011 and 2015. MATERIALS AND METHODS: We analyzed the claims data from the Health Insurance Review and Assessment Service to estimate the clinical utilization of RT. The source population consisted of all patients who had any of the International Classification of Diseases 10th revision cancer diagnoses (C00-C97) and those with diagnostic codes D00-D48, who were also associated with at least one of the procedure codes related to RT. RESULTS: The total number of patients who received RT in 2011, 2012, 2013, 2014, and 2015 were 54,810, 59,435, 61,839, 64,062, and 66,183, respectively. Among them, the total numbers of male and female patients were 24,946/29,864 in 2011, 27,211/32,224 in 2012, 28,111/33,728 in 2013, 29,312/34,750 in 2014, and 30,266/35,917 in 2015. The utilization rate of RT in cancer patients has also increased steadily over the same period from 25% to 30%. The five cancers that were most frequently treated with RT between 2011 and 2012 were breast, lung, colorectal, liver, and uterine cervical cancers. However, the fifth most common cancer treated with RT that replaced uterine cervical cancer in 2013 was prostate cancer. More than half of cancer patients (64%) were treated with RT in the capital area (Seoul, Gyeonggi, and Incheon). CONCLUSION: The total number of patients who underwent RT increased steadily from 2011 to 2015 in Korea. The utilization rate of RT in cancer patients is also increasing.

Stereotactic body radiation therapy for liver oligo-recurrence and oligo-progression from various tumors

PURPOSE: To evaluate the outcomes of stereotactic body radiation therapy (SBRT) for patients with liver oligo-recurrence and oligo-progression from various primary tumors. MATERIALS AND METHODS: Between 2002 and 2013, 72 patients with liver oligo-recurrence (oligo-metastasis with a controlled primary tumor) and oligo-progression (contradictory progression of a few sites of disease despite an overall tumor burden response to therapy) underwent SBRT. Of these, 9 and 8 patients with uncontrollable distant metastases and patients immediate loss to follow-up, respectively, were excluded. The total planning target volume was used to select the SBRT dose (median, 48 Gy; range, 30 to 60 Gy, 3–4 fractions). Toxicity was evaluated using the Common Toxicity Criteria for Adverse Events v4.0. RESULTS: We evaluated 55 patients (77 lesions) treated with SBRT for liver metastases. All patients had controlled primary lesions, and 28 patients had stable lesions at another site (oligo-progression). The most common primary site was the colon (36 patients), followed by the stomach (6 patients) and other sites (13 patients). The 2-year local control and progression-free survival rates were 68% and 22%, respectively. The 2- and 5-year overall survival rates were 56% and 20%, respectively. The most common adverse events were grade 1–2 fatigue, nausea, and vomiting; no grade ≥3 toxicities were observed. Univariate analysis revealed that oligo-progression associated with poor survival. CONCLUSION: SBRT for liver oligo-recurrence and oligo-progression appears safe, with similar local control rates. For liver oligo-progression, criteria are needed to select patients in whom improved overall survival can be expected through SBRT.

The clinical utilization of radiation therapy in Korea between 2009 and 2013

PURPOSE: The purpose of this study was to estimate the clinical utilization of radiation therapy (RT) in Korea between 2009 and 2013. MATERIALS AND METHODS: We analyzed open claims data from the Health Insurance Review and Assessment Service. The subjects were patients who had diagnostic codes C00-C97 or D00-D48 according to the 10th revision of the International Classification of Diseases, with procedure codes indicating RT treatment. RESULTS: The total number of patients who received RT in 2009, 2010, 2011, 2012, and 2013 were 45,571, 49,593, 54,671, 59,172, and 61,485, respectively. Among them, the total numbers of male and female patients were 20,780/24,791 in 2009, 22,711/26,882 in 2010, 24,872/29,799 in 2011, 27,101/32,071 in 2012, and 27,941/33,544 in 2013. The five cancers that were most frequently treated with RT between 2009 and 2012 were breast, lung, colorectal, liver, and uterine cervical cancers. However, the fifth most common cancer treated with RT that replaced uterine cervical cancer in 2013 was prostate cancer. The three leading types of cancer among the male patients were lung, colorectal, and liver cancers, whereas in female patients, they were breast, uterine cervical, and lung cancers. The type of cancer most commonly treated by RT was cancer of the central nervous system in patients aged 20 years or less, breast cancer in patients aged 30-50 years, and lung cancer in patients aged 60 years or more. CONCLUSION: Data from this study provided the clinical utilization of RT in Korea between 2009 and 2013.

The Clinical Status of Radiation Therapy in Korea in 2009 and 2013 / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The purpose of this study is to estimate the clinical status of radiation therapy (RT) in Korea. MATERIALS AND METHODS: We analyzed open claims data from the Health Insurance Review and Assessment Service (HIRA). The subjects were patients with malignant neoplasms who had procedure codes concerning RT in 2009 and 2013. RESULTS: The total numbers of patients who underwent RT in 2009 and 2013 were 42,483 and 56,850, respectively. The numbers of men and women were 20,012 and 22,471 in 2009 and 26,936 and 29,914 in 2013, respectively. The five most frequent RT sites were metastatic, breast, gastrointestinal, thoracic, and gynecologic cancers in 2009, and metastatic, breast, gastrointestinal, thoracic and head and neck cancers in 2013. The three leading types of cancer among men were metastatic, gastrointestinal, and thoracic, and breast, metastatic, and gynecologic among women. According to age, the most common treatment site was the central nervous system for those aged 20 years or less, the breast for those in their 30s to 50s, and metastatic sites for those in their 60s or older. CONCLUSION: Data from this study provide an overview of the clinical status of RT in Korea.

Low Hepatic Toxicity in Primary and Metastatic Liver Cancers after Stereotactic Ablative Radiotherapy Using 3 Fractions

This study evaluated the incidence of hepatic toxicity after stereotactic ablative radiotherapy (SABR) using 3 fractions to the liver, and identified the predictors for hepatic toxicity. We retrospectively reviewed 78 patients with primary and metastatic liver cancers, who underwent SABR using 3 fractions between 2003 and 2011. To examine the incidence of hepatic toxicity, we defined newly developed hepatic toxicity> or =grade 2 according to the National Cancer Institute Common Terminology Criteria for Adverse Events v4.0 within 3 months after the end of SABR as a significant adverse event. To identify the predictors for hepatic toxicity, we analyzed several clinical and dosimetric parameters (rV(5Gy)-rV(35Gy): normal liver volume receiving or =grade 2 occurred in 10 patients (13%): grade 2 in 9 patients and grade 3 in 1 patient. On univariate analysis, baseline Child-Pugh (CP) score (5 vs. 6-8), normal liver volume, and planning target volume were the significant clinical predictors. All dosimetric parameters were significant: rV(20Gy) was the most significant predictor. On multivariate analysis, baseline CP score (hazard ratio, 0.026; P=0.001) was the only significant predictor. In conclusion, SABR using 3 fractions in primary and metastatic liver cancers produces low hepatic toxicity, especially in patients with a baseline CP score of 5. However, further studies are needed to minimize hepatic toxicity in patients with baseline CP scores> or =6.

Outcomes of stereotactic body radiotherapy for unresectable primary or recurrent cholangiocarcinoma

PURPOSE: To report the results of stereotactic body radiotherapy (SBRT) for unresectable primary or recurrent cholangiocarcinoma. MATERIALS AND METHODS: From January 2005 through August 2013, 58 patients with unresectable primary (n = 28) or recurrent (n = 30) cholangiocarcinoma treated by SBRT were retrospectively analyzed. The median prescribed dose was 45 Gy in 3 fractions (range, 15 to 60 Gy in 1-5 fractions). Patients were treated by SBRT only (n = 53) or EBRT + SBRT boost (n = 5). The median tumor volume was 40 mL (range, 5 to 1,287 mL). RESULTS: The median follow-up duration was 10 months (range, 1 to 97 months). The 1-year, 2-year overall survival rates, and median survival were 45%, 20%, and 10 months, respectively. The median survival for primary group and recurrent group were 5 and 13 months, respectively. Local control rate at 1-year and 2-year were 85% and 72%, respectively. Disease progression-free survival rates at 1-year and 2-year were 26% and 23%, respectively. In univariate analysis, ECOG performance score (0-1 vs. 2-3), treatment volume ( or =50 mL), and pre-SBRT CEA level ( or =5 ng/mL) were significant in overall survival rate. In multivariate analysis, ECOG score (p = 0.037) and tumor volume (p = 0.030) were statistically significant. In the recurrent tumor group, patients with >12 months interval from surgery to recurrence showed statistically significant higher overall survival rate than those with or =grade 3 complications. CONCLUSION: SBRT can be considered as an effective local modality for unresectable primary or recurrent cholangiocarcinoma.

Radiosurgery for Recurrent Brain Metastases after Whole-Brain Radiotherapy : Factors Affecting Radiation-Induced Neurological Dysfunction

OBJECTIVE: We retrospectively analyzed survival, local control rate, and incidence of radiation toxicities after radiosurgery for recurrent metastatic brain lesions whose initial metastases were treated with whole-brain radiotherapy. Various radiotherapeutical indices were examined to suggest predictors of radiation-related neurological dysfunction. METHODS: In 46 patients, total 100 of recurrent metastases (mean 2.2, ranged 1-10) were treated by CyberKnife radiosurgery at average dose of 23.1 Gy in 1 to 3 fractions. The median prior radiation dose was 32.7 Gy, the median time since radiation was 5.0 months, and the mean tumor volume was 12.4 cm3. Side effects were expressed in terms of radiation therapy oncology group (RTOG) neurotoxicity criteria. RESULTS: Mass reduction was observed in 30 patients (65%) on MRI. After the salvage treatment, one-year progression-free survival rate was 57% and median survival was 10 months. Age (6 months) toxicity occurred in 21%, respectively. Less acute toxicity was observed with small tumors (<10 cm3, p=0.03), and less chronic toxicity occurred at lower cumulative doses (<100 Gy, p=0.004). "Radiation toxicity factor" (cumulative dose times tumor volume of <1,000 Gyxcm3) was a significant predictor of both acute and chronic CNS toxicities. CONCLUSION: Salvage CyberKnife radiosurgery is effective for recurrent brain metastases in previously irradiated patients, but careful evaluation is advised in patients with large tumors and high cumulative radiation doses to avoid toxicity.

The Usefulness of 18F-FDG PET/CT for Predicting the Response of Locally Advanced Rectal Cancer to Neoadjuvant Chemoradiation Therapy / 대한방사선종양학회지

PURPOSE: This study aimed at assessing the value of fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET) for predicting the response of locally advanced rectal cancer to neoadjuvant CRT. MATERIALS AND METHODS: Between August 2006 and January 2008, we prospectively enrolled 20 patients with locally advanced rectal cancer and who were treated with neoadjuvant CRT at the Korea Institute of Radiological and Medical Sciences. The treatment consisted of radiation therapy and chemotherapy, and this was followed by curative resection 6 weeks later. All the patients underwent 18F-FDG PET/CT both before CRT and 6 weeks after completing CRT. The measurements of the FDG uptake (SUV(max)), the absolute difference (DeltaSUV(max)) and the percent SUV(max) difference (response index, RI(SUV)) between the pre- and post-CRT 18F-FDG PET/CT scans were assessed. The measurements of the metabolic volume, the absolute difference (Delta metabolic volume) and the percent metabolic volume difference (response index, RI(metabolic volume)) were also assessed. RESULTS: Of the 20 patients who underwent surgery, 11 patients (55%) were classified as responders according to Dworak's classification. The post-CRT SUV(max) was significantly lower than the pre-CRT SUV(max). However, there were no significant differences in the SUV(max) and the metabolic volume reduction between the responders and non-responders. We used a minimum SUV(max) reduction of 67% as the cut-off value for defining a response, with a sensitivity of 45.5%, a specificity of 88.9%, a positive predictive value of 77% and a negative predictive value of 53.8%. CONCLUSION: Although there were no statistically significant results in this study, other studies have revealed that 18F-FDG PET/CT has the potential to assess the tumor response to neoadjuvant CRT in patients with locally advanced rectal cancer.

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.

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.

Accelerated Hyperfractionated Radiotherapy for Locally Advanced Uterine Cervix Cancers / 대한방사선종양학회지

PURPOSE: To assess the efficacy of the use of accelerated hyperfractionated radiotherapy (AHRT) for locally advanced uterine cervix cancers. MATERIALS AND METHODS: Between May 2000 and September 2002, 179 patients were identified with FIGO stage IIB, IIIB, and IVA cancers. Of the 179 patients, 45 patients were treated with AHRT (AHRT group) and 134 patients were treated with conventional radiotherapy (CRT group), respectively. Patients undergoing the AHRT regimen received a dose of 30 Gy in 20 fractions (1.5 Gyx2 fractions/day) to the whole pelvis. Subsequently, with a midline block, we administered a parametrial boost with a dose of 20 Gy using 2 Gy fractions. Patients also received two courses of low-dose-rate brachytherapy, up to a total dose of 85~90 Gy to point A. In the CRT group of patients, the total dose to point A was 85~90 Gy. The overall treatment duration was a median of 37 and 66 days for patients that received AHRT and CRT, respectively. Statistical analysis was calculated by use of the Kaplan-Meier method, the log-rank test, and Chi-squared test. RESULTS: For patients that received cisplatin-based concurrent chemotherapy and radiotherapy, the local control rate at 5 years was 100% and 79.2% for the AHRT and CRT group of patients, respectively (p=0.028). The 5-year survival rate for patients with a stage IIB bulky tumor was 82.6% and 62.1% for the AHRT group and CRT group, respectively (p=0.040). There was no statistically significant difference for severe late toxicity between the two groups (p=0.561). CONCLUSION: In this study, we observed that treatment with AHRT with concurrent chemotherapy allows a significant advantage of local control and survival for locally advanced uterine cervix cancers.

Distortion of the Dose Profile in a Three-dimensional Moving Phantom to Simulate Tumor Motion during Image-guided Radiosurgery / 대한방사선종양학회지

PURPOSE: Respiratory motion is a considerable inhibiting factor for precise treatment with stereotactic radiosurgery using the CyberKnife (CK). In this study, we developed a moving phantom to simulate three-dimensional breathing movement and investigated the distortion of dose profiles between the use of a moving phantom and a static phantom. MATERIALS AND METHODS: The phantom consisted of four pieces of polyethylene; two sheets of Gafchromic film were inserted for dosimetry. Treatment was planned to deliver 30 Gy to virtual tumors of 20, 30, 40, and 50 mm diameters using 104 beams and a single center mode. A specially designed robot produced three-dimensional motion in the right-left, anterior-posterior, and craniocaudal directions of 5, 10 and 20 mm, respectively. Using the optical density of the films as a function of dose, the dose profiles of both static and moving phantoms were measured. RESULTS: The prescribed isodose to cover the virtual tumors on the static phantom were 80% for 20 mm, 84% for 30 mm, 83% for 40 mm and 80% for 50 mm tumors. However, to compensate for the respiratory motion, the minimum isodose levels to cover the moving target were 70% for the 30~50 mm diameter tumors and 60% for a 20 mm tumor. For the 20 mm tumor, the gaps between the isodose curves for the static and moving phantoms were 3.2, 3.3, 3.5 and 1.1 mm for the cranial, caudal, right, and left direction, respectively. In the case of the 30 mm tumor, the gaps were 3.9, 4.2, 2.8, 0 mm, respectively. In the case of the 40 mm tumor, the gaps were 4.0, 4.8, 1.1, and 0 mm, respectively. In the case of the 50 mm diameter tumor, the gaps were 3.9, 3.9, 0 and 0 mm, respectively. CONCLUSION: For a tumor of a 20 mm diameter, the 80% isodose curve can be planned to cover the tumor; a 60% isodose curve will have to be chosen due to the tumor motion. The gap between these 80% and 60% curves is 5 mm. In tumors with diameters of 30, 40 and 50 mm, the whole tumor will be covered if an isodose curve of about 70% is selected, equivalent of placing a respiratory margin of below 5 mm. It was confirmed that during CK treatment for a moving tumor, the range of distortion produced by motion was less than the range of motion itself.

The Clinicopathological Factors That Determine a Local Recurrence of Rectal Cancers That Have Been Treated with Surgery and Chemoradiotherapy / 대한방사선종양학회지

PURPOSE: To evaluate the pathological prognostic factors related to local recurrence after radical surgery and adjuvant radiation therapy in advanced rectal cancer. MATERIALS AND METHODS: Fifty-four patients with advanced rectal cancer who were treated with radical surgery followed by adjuvant radiotherapy and chemotherapy between February 1993 and December 2001 were enrolled in this study. Among these patients, 14 patients experienced local recurrence. Tissue specimens of the patients were obtained to determine pathologic parameters such as histological grade, depth of invasion, venous invasion, lymphatic invasion, neural invasion and immunohistopathological analysis for expression of p53, Ki-67, c-erb, ezrin, c-met, phosphorylated S6 kinase, S100A4, and HIF-1 alpha. The correlation of these parameters with the tumor response to radiotherapy was statistically analyzed using the chi-square test, multivariate analysis, and the hierarchical clustering method. RESULTS: In univariate analysis, the histological tumor grade, venous invasion, invasion depth of the tumor and the over expression of c-met and HIF-1 alpha were accompanied with radioresistance that was found to be statistically significant. In multivariate analysis, venous invasion, invasion depth of tumor and over expression of c-met were also accompanied with radioresistance that was found to be statistically significant. By analysis with hierarchical clustering, the invasion depth of the tumor, and the over expression of c-met and HIF-1 alpha were factors found to be related to local recurrence. Whereas 71.4% of patients with local recurrence had 2 or more these factors, only 27.5% of patients without local recurrence had 2 or more of these factors. CONCLUSION: In advanced rectal cancer patients treated by radical surgery and adjuvant chemo-radiation therapy, the poor prognostic factors found to be related to local recurrence were HIF-1 alpha positive, c-met positive, and an invasion depth more than 5.5 mm. A prospective study is necessary to confirm whether these factors would be useful clinical parameters to measure and predict a radio-resistance group of patients.

Locally Advanced, Unresectable Pancreatic Cancer Treated by Stereotactic Radiation Therapy / 대한방사선종양학회지

PURPOSE: In order to find out whether stereotactic radiation therapy (RT) using CyberKnife (CK) could improve survival rate and lower acute toxicity compared to conventional RT. MATERIALS AND METHODS: From April 2003 through April 2004, 19 patients with Eastern Cooperative Oncology Group (ECOG) performance status 80 cc (p-value80 cc showed better survival rate. CONCLUSION: In terms of survival, the efficacy of stereotactic radiation therapy using CK was found to be superior or similar to other recent studies achieved with conventional RT with intensive chemotherapy, high dose conformal RT, intraoperative RT (IORT), or intensity modulated RT (IMRT). Furthermore, severe toxicity was not observed. Short treatment time in relation to the short life expectancy gave patients more convenience and, finally, quality of life would be increased. Consequently, this could be regarded as an effective novel treatment modality for locally advanced, unresectable pancreas cancer. PTV would be a helpful prognostic factor for CK.

Survey on Radiotherpy Protocols for the Rectal Cancers among the Korean Radiation Oncologists in 2002 for the Development of the Patterns of Care Study of Radiation Therapy / 대한방사선종양학회지

PURPOSE: To conduct a nationwide survery on the principles in radiotherapy for rectal cancer, and develop the framework of a database of Korean Patterns of Care Study. MATERIALS AND METHODS: A consensus committee was established to develop a tool for measuring the patterns in radiotherapy protocols for rectal cancer. The panel was composed of radiation oncologists from 18 hospitals in Seoul Metropolitan area. The committee developed a survey format to analyze radiation oncologist's treatment principles for rectal cancer. The survey items developed for measuring the treatment principles were composed of 1) 8 eligibility criteria, 2) 20 items for staging work-ups and prognostic factors, 3) 7 items for principles of combined surgery and chemotherapy, 4) 9 patient set-ups, 5) 19 determining radiation fields, 6) 5 radiotherapy treatment plans, 7) 4 physical/laboratory examination to monitor a patient's condition during treatment, and 8) 10 follow-up evaluations. These items were sent to radiation oncologists in charge of gastrointestinal malignancies in all hospitals (48 hospitals) in Korea to which 30 replies were received (63%). RESULTS: Most of the survey items were replied to without no major differences between the repliers, but with the following items only 50% of repliers were in agreement:1) indications of preoperative radiation, 2) use of endorectal ultrasound, CT scan, and bone scan for staging work-ups, 3) principles of combining chemotherapy with radiotherapy, 4) use of contrast material for small bowel delineation during simulation, 5) determination of field margins, and 6) use of CEA and colonoscopy for follow-up evaluations. CONCLUSION: The items where considerable disagreement was shown among the radiation oncologists seemed to make no serious difference in the treatment outcome, but a practical and reasonable consensus should be reached by the committee, with logical processes of agreement. These items can be used for a basic database for the Patterns of Care Study, which will survey the practical radiotherapy patterns for rectal cancer in Korea.

Confirmation of the Dose Distribution by Stereotactic Radiosurgery Technique with a Multi-purpose Phantom / 대한방사선종양학회지

PURPOSE: For the purpose of quality assurance of self-developed stereotactic radiosurgery system, a multi-purpose phantom was fabricated, and accuracy of radiation dose distribution during radiosurgery was measured using this phantom. MATERIALS AND METHODS: A farmer chamber, a 0.125 cc ion chamber and a diode detector were used for the dosimetry. Six MV x-ray from a linear accelerator (CL2100C, Varian) with stereotactic radiosurgery technique (Green Knife) was used, and multi-purpose phantom was attached to a stereotactic frame (Fisher type). Dosimetry was done by combinations of locations of the detectors in the phantom, fixed or arc beams, gantry angles (20 ~100 ), and size of the circular tertiary collimators (inner diameters of 10 degrees~40 degrees mm). RESULTS: The measurement error was less than 0.5% by Farmer chamber, 0.5% for 0.125 cc ion chamber, and less than 2% for diode detector for the fixed beam, single arc beam, and 5-arc beam setup. CONCLUSION: We confirmed the accuracy of dose distribution with the radiosurgery system developed in our institute and the data from this study would be able to be effectively used for the improvement of quality assurance of stereotactic radiosurgery or fractionated stereotactic radiotherapy system.

Treatment Results of Esophageal Carcinoma Treated by Radiation Therapy / 대한방사선종양학회지

PURPOSE: To determine treatment protocol for inoperable esophageal cancer patients, we evaluated survival rate and prognostic factors. MATERIALS AND METHODS: We evaluated esophageal cancer treated by curative or palliative aim in KCCH from 1992 to 1996, retrospectively. Recurrent or underdose case below 40 Gy were excluded. The number of male and female were 35 and 5, respectively. Thirty-eight patients were squamous carcinoma and 2 patients were not biopsy proven. Ten patients were treated with radiation therapy and chemotherapy. Median dose of radiation therapy was 59.4 Gy and the range was 40-60 Gy. RESULTS:The median survival is 6.5 months and 1-year survival rate was 28.3%. Age, location, radiation dose and chemotherapy were not significant prognostic factors. Median survivals of patients with below stage III and over stage IVA were 7.6 and 6.2 months respectively, but it is not significant. CONCLUSION:The survival for esophageal cancer is very poor. For patients with curative aim, chemotherapy must be considered. For patients with palliative aim, short-term external beam radiation therapy and/or brachytherapy must be considered.

The Clinical Characteristics of Hyperthyroidism Combined with Ocular Myasthenia Gravis: Report of Six cases / 대한내분비학회지

Myasthenia gravis is an autoimmune disease characterized by impaired neuromuscular transmission due to circulating antiacetylcholine receptor autoantibodies. The relation between myasthenia gravis and thyroid disease remains unclarified. The association is thought to be uncommon and approximately 0.2% of myasthenia gravis has been reported in patients with autoimmune thyroid disease. Clinical expression of myasthenia gravis varies, ranging from a mild localized disease such as ocular myasthenia gravis (OMG) to a severe generalized disease. A higher frequency of thyroid antibodies has been observed in OMG compared to generalized myasthenia gravis, but the exact mechanisms of this increased association between OMG and thyroid autoimmunity has not been confirmed. The "see-saw" relationship between hyperthyroidism and myasthenia gravis is presented by some authors, while others reported that the optimal maintenance of euthyroid status was essential in treatment. Today many authors agree to the latter and we think that the adequate control of hyperthyroidism is more important. We have experienced six cases of hyperthyroidism combined with OMG and it was somewhat difficult to diagnose myasthenia gravis when the patient have Graves' ophthalmopathy.

The Stucture of Korean Radiation Oncology in 1997 / 대한방사선종양학회지

PURPOSE: To measure the basic structural characteristics of radiation oncology facilities in Korea during 1997 and to compare personnel, equipments and patient loads between Korea and developed countries. METHOD AND MATERIALS: Mail serveys were conducted in 1998 and data on treatment machines, personnel and performed new patients were collected. Responses were obtained from the 100 percent of facilities. The consensus data of the whole contry were summarized using Microsoft Excel program. RESULTS: In Korea during 1997, 42 facilities delivered megavoltage radiation theraphy with 71 treatment machines, 100 radiation oncologists, 26 medical physicist, 205 technologists and 19,773 new patients. Eighty nine percent of facilities in Korea had linear accelators at least 6 MeV maxium photon energy. Ninety five percent of facilities had simulators while five percent of facilities had no simulator. Ninety one percent of facilities had computer planning systems and eighty three percent of facilities reported that they had a written quality assurace program. Thirty six percent of facilities had only one radiation oncologist and thirty eight percent of facilities had no medical physicists. The median of the distribution of annual patients load of a facility, patients load per a machine, patients load per a radiation oncologist, patients load per a therapist and therapists per a machine in Korea were 348 patients per a year, 263 patients per a machine, 171 patients per a radiation oncologis, 81 patients per a therapist, and 3 therapists per a machine respectively. CONCLUSION: The whole scale of the radiation oncology departments in Korea was smaller than Japan and USA in population ratio regard. In case of hardware level like linear accelerators, simulators and computer planning systems, there was no big diffrences bewteen Korea and USA. The patients loads of radiation oncologists and therapists had no significient differences as compared with USA. However, it was desirable to consider the part time system in USA because there were a lot of hospitals which did not employ medical physicists.