Clinical Outcomes of Postoperative Radiotherapy Following Radical Prostatectomy in Patients with Localized Prostate Cancer: A Multicenter Retrospective Study (KROG 18-01) of a Korean Population / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#The purpose of this study was to investigate the clinical outcomes of postoperative radiotherapy (PORT) patients who underwent radical prostatectomy for localized prostate cancer. @*Materials and Methods@#Localized prostate cancer patients who received PORT after radical prostatectomy between 2001 and 2012 were identified retrospectively in a multi-institutional database. In total, 1,117 patients in 19 institutions were included. Biochemical failure after PORT was defined as prostate-specific antigen (PSA) ≥ nadir+2 after PORT or initiation of androgen deprivation therapy (ADT) for increasing PSA regardless of its value. @*Results@#Ten-year biochemical failure-free survival, clinical failure-free survival, distant metastasisfree survival, overall survival (OS), and cause-specific survival were 60.5%, 76.2%, 84.4%, 91.1%, and 96.6%, respectively, at a median of 84 months after PORT. Pre-PORT PSA ≤ 0.5 ng/ml and Gleason’s score ≤ 7 predicted favorable clinical outcomes, with 10-year OS rates of 92.5% and 94.1%, respectively. The 10-year OS rate was 82.7% for patients with a PSA > 1.0 ng/mL and 86.0% for patients with a Gleason score of 8-10. The addition of longterm ADT (≥ 12 months) to PORT improved OS, particularly in those with a Gleason score of 8-10 or ≥ T3b. @*Conclusion@#Clinical outcomes of PORT in a Korean prostate cancer population were very similar to those in Western countries. Lower Gleason score and serum PSA level at the time of PORT were significantly associated with favorable outcomes. Addition of long-term ADT (≥ 12 months) to PORT should be considered, particularly in unfavorable risk patients with Gleason scores of 8-10 or ≥ T3b.

Effects of Radiation Therapy on Established Neurogenic Heterotopic Ossification

Heterotopic ossification (HO) is frequently seen on rehabilitation units after spinal cord injuries, fractures, brain injuries, and limb amputations. Currently, there is no effective treatment for HO other than prophylaxis with anti-inflammatory medications, irradiation, and bisphosphonate administration. These prophylactic treatments are not effective for managing ectopic bone once it has formed. Here we describe three cases of established neurogenic HO treated with radiation therapy (RT). All patients had decreased serum alkaline phosphatase (ALP) and bone-specific ALP levels with decreased pain but increased range of motion immediately after RT. Post-treatment X-rays revealed no further growth of the HO. All patients maintained clinical and laboratory improvements 4 or 6 months after the RT. Our results suggest that RT is safe and effective in decreasing pain and activity of neurogenic HO.

Quality Assurance of Volumetric Modulated Arc Therapy for Elekta Synergy / 의학물리

For applying the quality assurance (QA) of volumetric modulated arc therapy (VMAT) introduced in Eulji Hospital, we classify it into three different QA steps, treatment planning QA, pretreatment delivering QA, and treatment verifying QA. These steps are based on the existing intensity modulated radiation therapy (IMRT) QA that is currently used in our hospital. In each QA step, the evaluated items that are from QA program are configured and documented. In this study, QA program is not only applied to actual patient treatment, but also evaluated to establish a reference of clinical acceptance in pretreatment delivering QA. As a result, the confidence limits (CLs) in the measurements for the high-dose and low-dose regions are similar to the conventional IMRT level, and the clinical acceptance references in our hospital are determined to be 3 to 5% for the high-dose and the low-dose regions, respectively. Due to the characteristics of VMAT, evaluation of the intensity map was carried out using an ArcCheck device that was able to measure the intensity map in all directions, 360degrees. With a couple of dosimetric devices, the gamma index was evaluated and analyzed. The results were similar to the result of individual intensity maps in IMRT. Mapcheck, which is a 2-dimensional (2D) array device, was used to display the isodose distributions and gave very excellent local CL results. Thus, in our hospital, the acceptance references used in practical clinical application for the intensity maps of 360degrees directions and the coronal isodose distributions were determined to be 93% and 95%, respectively. To reduce arbitrary uncertainties and system errors, we had to evaluate the local CLs by using a phantom and to cooperate with multiple organizations to participate in this evaluation. In addition, we had to evaluate the local CLs by dividing them into different sections about the patient treatment points in practical clinics.

A Study of Optimized MRI Parameters for Polymer Gel Dosimetry / 의학물리

In order to verify exact dose distributions in the state-of-the-art radiation techniques, a newly designed three-dimensional dosimeter and technique has been took strongly into consideration. The main purpose of our study is to verify the optimized parameters of polymer gel as a real volumetric dosimeter in terms of the various study of MRI. We prepared a gel dosimeter by combing 8% of gelatin, 8% of MAA, and 10 mM of THPC. We used a Co-60 gamma-ray teletherapy unit and delivered doses of 0, 2, 4, 6, 8, 10, 12, and 14 Gy to each polymer gel with a solid phantom. We used a fast spin-echo pulse to acquire the characterized T2 time of MRI. The signal noise ratio (SNR) of the head & neck coil was a relatively lower sensitivity than the body coil; therefore the dose uncertainty of head & neck coil would be lower than body coil's. But the dose uncertainty and resolution of the head & neck coil were superior to the body coil in this study. The TR time between 1,500 ms and 2,000 ms showed no significant difference in the dose resolution, but TR of 1,500 ms showed less dose uncertainty. For the slice thickness of 2.5 mm, less dose uncertainty of TE times was at 4 Gy, as well, it was the lowest result over 4 Gy at TE of 12 ms. The dose uncertainty was not critical up to 6 Gy, but the best dose resolution was obtained at 20 ms up to 8 Gy. The dose resolution shows the lowest value was over 20 ms and was an excellent result in the number of excitation (NEX) of three. The NEX of two was the highest dose resolution. We concluded that the better result of slice thickness versus NEX was related to the NEX increment and thin slice thickness.

The Comparison of Usefulness between MDCT Angiography and DSA in the Diagnosis of Intracranial Aneurysm / 의학물리

The purpose of this study was to compare the image between DSA and MDCT Angiography and to examine whether MDCT Angiography could be useful as a screening test for the diagnosis of cerebral aneurysm in patients who were diagnosed with cerebral aneurysm on DSA. Of patients who were diagnosed with cerebral aneurysm DSA at University Hospital, 194 patients who concomitantly underwent MDCT Angiography were enrolled in the current retrospective study. The methods for analyzing cerebral aneurysm were to analyze the presence of cerebral aneurysm on DSA and MDCT Angiography. In cases in which it exceeded 1, the corresponding cases were classified as narrow-neck aneurysms. In otherwise cases, they were classified as wide-neck aneurysms. Thus, a comparative analysis could be performed to ascertain if cases were narrow-neck or wide-neck aneurysms. As compared with DSA, the sensitivity of MDCT Angiography for cerebral aneurysm was measured to be 97.4%. The degree of consistency between narrow-neck and wide-neck aneurysms was 90.2% and the proportion of undetectable an at MDCT Angiography was 2.54%. mean size was 2.4 mm. It is expected that a non-invasive diagnostic modality for a screening test for cerebral aneurysm, MDCT Angiography might be a very useful regimen as compared with an invasive one, DSA.

Validation of Radiation Volume by Analysis of Recurrence Pattern in Breast-conserving Treatment for Early Breast Cancer / 한국유방암학회지

PURPOSE: To assess the appropriateness of radiotherapy volume for patients receiving breast-conserving treatment (BCT) through analysis of recurrence pattern and factors affecting recurrence. METHODS: From 1991 to 1996, 362 patients who received BCT were retrospectively evaluated. The radiation volume was the involved breast alone in the patients with less than 4 positive axillary lymph nodes (LNs), and breast and supraclavicular fossa in patients with 4 or more positive axillary LNs. The median follow-up period was 123 months (range, 3-169 months). RESULTS: Ten-year overall, disease-free, local recurrence-free, and regional recurrence-free survival rates were 86.2%, 82.2%, 95.9%, and 95.2%, respectively. Among 310 patients receiving radiotherapy on the breast alone, 15 (4.8%) had regional recurrence. In particular, patients with inner quadrant lesions had high regional recurrence rates (11/98, 11.2%) (p<0.001). CONCLUSION: These low local recurrence rates may reveal that the current radiotherapy technique was successful. However, in cases of inner quadrant lesions, there were a considerable number of regional recurrences, even in N0 cases. This may suggest a potential role for irradiation on regional LNs in this group.

Development of Electronic Medical Chart for Radiation Oncology / 의학물리

As the radiotherapy technique development, the needs for using of medical electronic chart in the department of radiation oncology is growing. However, the complexity of affairs of radiation oncology make it difficult to develop a electronic medical chart. In this study, we introduce the electronic medical chart developed by domestic hospital. The function and example of electronic medical chart designed as radiation treatment progress was showed and the future study was presented.

Development of Electronic Medical Chart for Radiation Oncology / 의학물리

As the radiotherapy technique development, the needs for using of medical electronic chart in the department of radiation oncology is growing. However, the complexity of affairs of radiation oncology make it difficult to develop a electronic medical chart. In this study, we introduce the electronic medical chart developed by domestic hospital. The function and example of electronic medical chart designed as radiation treatment progress was showed and the future study was presented.

A Study of the Radiotherapy Techniques for the Breast Including Internal Mammary Lymph Nodes / 대한방사선종양학회지

PURPOSE: This study was designed to determine the optimum radiotherapy technique for internal mammary node (IMN) irradiation after breast-conserving surgery. MATERIALS AND METHODS: We selected ten cases of early stage partial mastectomy for plan comparison. Five of the patients were treated to the right-side breast and the rest of the patients were treated to the left-side breast. For each case, four different treatment plans were made to irradiate the entire breast, IMNs and supraclavicular lymph nodes (SCLs). The four planning techniques include a standard tangential field (STF), wide tangential field (WTF), partially wide tangential field (PWT) and a photon-electron mixed field (PEM). We prescribed a dose of 50.4 Gy to the SCL field at a 3 cm depth and isocenter of the breast field. RESULTS: The dose distribution showed clear characteristics depending on the technique used. All of the techniques covered the breast tissue well. IMN coverage was also good, except for the STF, which was not intended to cover IMNs. For the cases of the left-side breasts, the volume of the heart that received more than 30 Gy was larger (in order) for the WTF, PWT, PEM and STF. For radiation pneumonitis normal tissue complication probability (NTCP), the PWT showed the best results followed by the STF. CONCLUSION: Despite the variety of patient body shapes, the PWT technique showed the best results for coverage of IMNs and for reducing the lung and heart dose.

Evaluation of Real-time Measurement Liver Tumor's Movement and Synchrony(TM) System's Accuracy of Radiosurgery using a Robot CyberKnife / 대한방사선종양학회지

PURPOSE: This study aimed to quantitatively measure the movement of tumors in real-time and evaluate the treatment accuracy, during the treatment of a liver tumor patient, who underwent radiosurgery with a Synchrony Respiratory motion tracking system of a robot CyberKnife. MATERIALS AND METHODS: The study subjects included 24 liver tumor patients who underwent CyberKnife treatment, which included 64 times of treatment with the Synchrony Respiratory motion tracking system (Synchrony(TM)). The treatment involved inserting 4 to 6 acupuncture needles into the vicinity of the liver tumor in all the patients using ultrasonography as a guide. A treatment plan was set up using the CT images for treatment planning uses. The position of the acupuncture needle was identified for every treatment time by Digitally Reconstructed Radiography (DRR) prepared at the time of treatment planning and X-ray images photographed in real-time. Subsequent results were stored through a Motion Tracking System (MTS) using the Mtsmain.log treatment file. In this way, movement of the tumor was measured. Besides, the accuracy of radiosurgery using CyberKnife was evaluated by the correlation errors between the real-time positions of the acupuncture needles and the predicted coordinates. RESULTS: The maximum and the average translational movement of the liver tumor were measured 23.5 mm and 13.9+/-5.5 mm, respectively from the superior to the inferior direction, 3.9 mm and 1.9+/-0.9 mm, respectively from left to right, and 8.3 mm and 4.9+/-1.9 mm, respectively from the anterior to the posterior direction. The maximum and the average rotational movement of the liver tumor were measured to be 3.3degrees and 2.6+/-1.3degrees, respectively for X (Left-Right) axis rotation, 4.8degrees and 2.3+/-1.0degrees, respectively for Y (Cranio-Caudal) axis rotation, 3.9degrees and 2.8+/-1.1degrees, respectively for Z (Anterior-Posterior) axis rotation. In addition, the average correlation error, which represents the treatment's accuracy was 1.1+/-0.7 mm. CONCLUSION: In this study real-time movement of a liver tumor during the radiosurgery could be verified quantitatively and the accuracy of the radiosurgery with the Synchrony Respiratory motion tracking system of robot could be evaluated. On this basis, the decision of treatment volume in radiosurgery or conventional radiotherapy and useful information on the movement of liver tumor are supposed to be provided.

Internal Mammary Lymph Node Irradiation after Breast Conservation Surgery: Radiation Pneumonitis versus Dose?Volume Histogram Parameters / 대한방사선종양학회지

PURPOSE: To evaluate the association between radiation pneumonitis and dose-volume histogram parameters and to provide practical guidelines to prevent radiation pneumonitis following radiotherapy administered for breast cancer including internal mammary lymph nodes. MATERIALS AND METHODS: Twenty patients with early breast cancer who underwent a partial mastectomy were involved in this study. The entire breast, supraclavicular lymph nodes, and internal mammary lymph nodes were irradiated with a dose of 50.4 Gy in 28 fractions. Radiation pneumonitis was assessed by both radiological pulmonary change (RPC) and by evaluation of symptomatic radiation pneumonitis. Dose-volume histogram parameters were compared between patients with grade or =2 RPC. The parameters were the mean lung dose, V10 (percent lung volume receiving equal to and more than 10 Gy), V20, V30, V40, and normal tissue complication probability (NTCP). RESULTS: Of the 20 patients, 9 (45%) developed grade 2 RPC and 11 (55%) did not develop RPC (grade 0). Only one patient developed grade 1 symptomatic radiation pneumonitis. Univariate analysis showed that among the dose-volume histogram parameters, NTCP was significantly different between the two RPC grade groups (p<0.05). Fisher's exact test indicated that an NTCP value of 45% was appropriate as an RPC threshold level. CONCLUSION: This study shows that NTCP can be used as a predictor of RPC after radiotherapy of the internal mammary lymph nodes in breast cancer. Clinically, it indicates that an RPC is likely to develop when the NTCP is greater than 45%.

The 1998, 1999 Patterns of Care Study for Breast Irradiation after Mastectomy in Korea / 대한방사선종양학회지

PURPOSE: To determine the patterns of evaluation and treatment in patients with breast cancer after mastectomy and treated with radiotherapy. A nationwide study was performed with the goal of improving radiotherapy treatment. MATERIALS AND METHODS: A web-based database system for the Korean Patterns of Care Study (PCS) for 6 common cancers was developed. Randomly selected records of 286 eligible patients treated between 1998 and 1999 from 17 hospitals were reviewed. RESULTS: The ages of the study patients ranged from 20 to 80 years (median age 44 years). The pathologic T stage by the AJCC was T1 in 9.7% of the cases, T2 in 59.2% of the cases, T3 in 25.6% of the cases, and T4 in 5.3% of the cases. For analysis of nodal involvement, N0 was 7.3%, N1 was 14%, N2 was 38.8%, and N3 was 38.5% of the cases. The AJCC stage was stage I in 0.7% of the cases, stage IIa in 3.8% of the cases, stage IIb in 9.8% of the cases, stage IIIa in 43% of the cases, stage IIIb in 2.8% of the cases, and IIIc in 38.5% of the cases. There were various sequences of chemotherapy and radiotherapy after mastectomy. Mastectomy and chemotherapy followed by radiotherapy was the most commonly performed sequence in 47% of the cases. Mastectomy, chemotherapy, and radiotherapy followed by additional chemotherapy was performed in 35% of the cases, and neoadjuvant chemoradiotherapy was performed in 12.5% of the cases. The radiotherapy volume was chest wall only in 5.6% of the cases. The volume was chest wall and supraclavicular fossa (SCL) in 20.3% of the cases; chest wall, SCL and internal mammary lymph node (IMN) in 27.6% of the cases; chest wall, SCL and posterior axillary lymph node in 25.9% of the cases; chest wall, SCL, IMN, and posterior axillary lymph node in 19.9% of the cases. Two patients received IMN only. The method of chest wall irradiation was tangential field in 57.3% of the cases and electron beam in 42% of the cases. A bolus for the chest wall was used in 54.8% of the tangential field cases and 52.5% of the electron beam cases. The radiation dose to the chest wall was 45~59.4 Gy (median 50.4 Gy), to the SCL was 45~59.4 Gy (median 50.4 Gy), and to the PAB was 4.8~38.8 Gy, (median 9 Gy) CONCLUSION: Different and various treatment methods were used for radiotherapy of the breast cancer patients after mastectomy in each hospital. Most of treatment methods varied in the irradiation of the chest wall. A separate analysis for the details of radiotherapy planning also needs to be followed and the outcome of treatment is needed in order to evaluate the different processes.

Reappraisal of Risk Factors Predicting Liver Complications from Radiotherapy for Hepatocellular Carcinoma / 대한간학회지

BACKGROUND/AIMS: Determination of the optimal radiotherapeutic parameters for radiotherapy of hepatocellular carcinoma (HCC) is still under investigation. The purpose of this study is to identify the risk factors associated with radiation-related morbidity. METHODS: We evaluated one hundred fifty-eight patients, who were given radiotherapy for HCC between January 1992 and March 2000. Radiation-induced liver disease (RILD) was defined as the development of nonmalignant ascites without disease progression and an anicteric elevation of the alkaline phosphatase level by at least twofold. Gastrointestinal toxicity was assessed by using the RTOG-EORTC scale. RESULTS: Six patients (3.8%) displayed RILD. In these patients, three patients had not responded to other previous treatments. Two patients with portal vein thrombosis or huge sized mass, above 10 cm, showed liver toxicity and two other patients presented with Child-Pugh class B liver cirrhosis. Eight patients (5%) had gastro-duodenal ulcers. In one of these 8 patients, the left lobe close to the stomach was involved and two patients had been treated for gastro-duodenal ulcer. In two more patients, the radiation field, with using anterior/posterior radiation ports, covered a significant volume of the gastrointestinal tract. One of eight patients had been irradiated with a large fraction size (250 cGy). CONCLUSIONS: The efforts should be made to reduce the radiation-related complications for hepatocellular carcinoma by considering the volume and the function of remaining liver, the location of tumor, the tumor size and the severity of liver cirrhosis.

Optimum Radiotherapy Schedule for Uterine Cervical Cancer based-on the Detailed Information of Dose Fractionation and Radiotherapy Technique / 대한방사선종양학회지

BACKGROUND: The best dose-fractionation regimen of the definitive radiotherapy for cervix cancer remains to be clearly determined. It seems to be partially attributed to the complexity of the affecting factors and the lack of detailed information on external and intra-cavitary fractionation. To find optimal practice guidelines, our experiences of the combination of external beam radiotherapy (EBRT) and high-dose-rate intracavitary brachytherapy (HDR-ICBT) were reviewed with detailed information of the various treatment parameters obtained from a large cohort of women treated homogeneously at a single institute. MATERIALS AND METHODS: The subjects were 743 cervical cancer patients (Stage IB 198, IIA 77, IIB 364, IIIA 7, IIIB 89 and IVA 8) treated by radiotherapy alone, between 1990 and 1996. A total external beam radiotherapy (EBRT) dose of 23.4~59.4 Gy (Median 45.0) was delivered to the whole pelvis. High-dose-rate intracavitary brachytherapy (HDR-ICBT) was also performed using various fractionation schemes. A Midline block (MLB) was initiated after the delivery of 14.4~43.2 Gy (Median 36.0) of EBRT in 495 patients, while in the other 248 patients EBRT could not be used due to slow tumor regression or the huge initial bulk of tumor. The point A, actual bladder & rectal doses were individually assessed in all patients. The biologically effective dose (BED) to the tumor (alpha/beta=10) and late-responding tissues (alpha/beta=3) for both EBRT and HDR-ICBT were calculated. The total BED values to point A, the actual bladder and rectal reference points were the summation of the EBRT and HDR-ICBT. In addition to all the details on dose-fractionation, the other factors (i.e. the overall treatment time, physicians preference) that can affect the schedule of the definitive radiotherapy were also thoroughly analyzed. The association between MD-BED Gy3 and the risk of complication was assessed using serial multiple logistic regression models. The associations between R-BED Gy3 and rectal complications and between V-BED Gy3 and bladder complications were assessed using multiple logistic regression models after adjustment for age, stage, tumor size and treatment duration. Serial Coxs proportional hazard regression models were used to estimate the relative risks of recurrence due to MD-BED Gy10, and the treatment duration. RESULTS: The overall complication rate for RTOG Grades 1~4 toxicities was 33.1%. The 5-year actuarial pelvic control rate for all 743 patients was 83%. The midline cumulative BED dose, which is the sum of external midline BED and HDR-ICBT point A BED, ranged from 62.0 to 121.9 Gy10 (median 93.0) for tumors and from 93.6 to 187.3 Gy3 (median 137.6) for late responding tissues. The median cumulative values of actual rectal (R-BED Gy3) and bladder point BED (V-BED Gy3) were 118.7 Gy3 (range 48.8~265.2) and 126.1 Gy3 (range: 54.9~267.5), respectively. MD-BED Gy3 showed a good correlation with rectal (p=0.003), but not with bladder complications (p=0.095). R-BED Gy3 had a very strong association (p=<0.0001), and was more predictive of rectal complications than A-BED Gy3. B-BED Gy3 also showed significance in the prediction of bladder complications in a trend test (p=0.0298). No statistically significant dose-response relationship for pelvic control was observed. The Sandwich and Continuous techniques, which differ according to when the ICR was inserted during the EBRT and due to the physicians preference, showed no differences in the local control and complication rates; there were also no differences in the 3 vs. 5 Gy fraction size of HDR-ICBT. CONCLUSION: The main reasons optimal dose-fractionation guidelines are not easily established is due to the absence of a dose-response relationship for tumor control as a result of the high-dose gradient of HDR-ICBT, individual differences in tumor responses to radiation therapy and the complexity of affecting factors. Therefore, in our opinion, there is a necessity for individualized tailored therapy, along with general guidelines, in the definitive radiation treatment for cervix cancer. This study also demonstrated the strong predictive value of actual rectal and bladder reference dosing therefore, vaginal gauze packing might be very important. To maintain the BED dose to less than the threshold resulting in complication, early midline shielding, the HDR-ICBT total dose and fractional dose reduction should be considered.

Optimum Radiotherapy Schedule for Uterine Cervical Cancer based-on the Detailed Information of Dose Fractionation and Radiotherapy Technique / 대한방사선종양학회지

BACKGROUND: The best dose-fractionation regimen of the definitive radiotherapy for cervix cancer remains to be clearly determined. It seems to be partially attributed to the complexity of the affecting factors and the lack of detailed information on external and intra-cavitary fractionation. To find optimal practice guidelines, our experiences of the combination of external beam radiotherapy (EBRT) and high-dose-rate intracavitary brachytherapy (HDR-ICBT) were reviewed with detailed information of the various treatment parameters obtained from a large cohort of women treated homogeneously at a single institute. MATERIALS AND METHODS: The subjects were 743 cervical cancer patients (Stage IB 198, IIA 77, IIB 364, IIIA 7, IIIB 89 and IVA 8) treated by radiotherapy alone, between 1990 and 1996. A total external beam radiotherapy (EBRT) dose of 23.4~59.4 Gy (Median 45.0) was delivered to the whole pelvis. High-dose-rate intracavitary brachytherapy (HDR-ICBT) was also performed using various fractionation schemes. A Midline block (MLB) was initiated after the delivery of 14.4~43.2 Gy (Median 36.0) of EBRT in 495 patients, while in the other 248 patients EBRT could not be used due to slow tumor regression or the huge initial bulk of tumor. The point A, actual bladder & rectal doses were individually assessed in all patients. The biologically effective dose (BED) to the tumor (alpha/beta=10) and late-responding tissues (alpha/beta=3) for both EBRT and HDR-ICBT were calculated. The total BED values to point A, the actual bladder and rectal reference points were the summation of the EBRT and HDR-ICBT. In addition to all the details on dose-fractionation, the other factors (i.e. the overall treatment time, physicians preference) that can affect the schedule of the definitive radiotherapy were also thoroughly analyzed. The association between MD-BED Gy3 and the risk of complication was assessed using serial multiple logistic regression models. The associations between R-BED Gy3 and rectal complications and between V-BED Gy3 and bladder complications were assessed using multiple logistic regression models after adjustment for age, stage, tumor size and treatment duration. Serial Coxs proportional hazard regression models were used to estimate the relative risks of recurrence due to MD-BED Gy10, and the treatment duration. RESULTS: The overall complication rate for RTOG Grades 1~4 toxicities was 33.1%. The 5-year actuarial pelvic control rate for all 743 patients was 83%. The midline cumulative BED dose, which is the sum of external midline BED and HDR-ICBT point A BED, ranged from 62.0 to 121.9 Gy10 (median 93.0) for tumors and from 93.6 to 187.3 Gy3 (median 137.6) for late responding tissues. The median cumulative values of actual rectal (R-BED Gy3) and bladder point BED (V-BED Gy3) were 118.7 Gy3 (range 48.8~265.2) and 126.1 Gy3 (range: 54.9~267.5), respectively. MD-BED Gy3 showed a good correlation with rectal (p=0.003), but not with bladder complications (p=0.095). R-BED Gy3 had a very strong association (p=<0.0001), and was more predictive of rectal complications than A-BED Gy3. B-BED Gy3 also showed significance in the prediction of bladder complications in a trend test (p=0.0298). No statistically significant dose-response relationship for pelvic control was observed. The Sandwich and Continuous techniques, which differ according to when the ICR was inserted during the EBRT and due to the physicians preference, showed no differences in the local control and complication rates; there were also no differences in the 3 vs. 5 Gy fraction size of HDR-ICBT. CONCLUSION: The main reasons optimal dose-fractionation guidelines are not easily established is due to the absence of a dose-response relationship for tumor control as a result of the high-dose gradient of HDR-ICBT, individual differences in tumor responses to radiation therapy and the complexity of affecting factors. Therefore, in our opinion, there is a necessity for individualized tailored therapy, along with general guidelines, in the definitive radiation treatment for cervix cancer. This study also demonstrated the strong predictive value of actual rectal and bladder reference dosing therefore, vaginal gauze packing might be very important. To maintain the BED dose to less than the threshold resulting in complication, early midline shielding, the HDR-ICBT total dose and fractional dose reduction should be considered.

Radiation Dose-escalation Trial for Glioblastomas with 3D-conformal Radiotherapy / 대한방사선종양학회지

PURPOSE: To investigate the effects of radiation dose-escalation on the treatment outcome, complications and the other prognostic variables for glioblastoma patients treated with 3D-conformal radiotherapy (3D-CRT). MATERIALS AND METHODS: Between Jan 1997 and July 2002, a total of 75 patients with histologically proven diagnosis of glioblastoma were analyzed. The patients who had a Karnofsky Performance Score (KPS) of 60 or higher, and received at least 50 Gy of radiation to the tumor bed were eligible. All the patients were divided into two arms; Arm 1, the high-dose group was enrolled prospectively, and Arm 2, the low-dose group served as a retrospective control. Arm 1 patients received 63~70 Gy (Median 66 Gy, fraction size 1.8~2 Gy) with 3D-conformal radiotherapy, and Arm 2 received 59.4 Gy or less (Median 59.4 Gy, fraction size 1.8 Gy) with 2D-conventional radiotherapy. The Gross Tumor Volume (GTV) was defined by the surgical margin and the residual gross tumor on a contrast enhanced MRI. Surrounding edema was not included in the Clinical Target Volume (CTV) in Arm 1, so as to reduce the risk of late radiation associated complications; whereas as in Arm 2 it was included. The overall survival and progression free survival times were calculated from the date of surgery using the Kaplan-Meier method. The time to progression was measured with serial neurologic examinations and MRI or CT scans after RT completion. Acute and late toxicities were evaluated using the Radiation Therapy Oncology Group neurotoxicity scores. RESULTS: During the relatively short follow up period of 14 months, the median overall survival and progression free survival times were 15+/-1.65 and 11+/-0.95 months, respectively. There was a significantly longer survival time for the Arm 1 patients compared to those in Arm 2 (p=0.028). For Arm 1 patients, the median survival and progression free survival times were 21+/-5.03 and 12+/-1.59 months, respectively, while for Arm 2 patients they were 14+/-0.94 and 10+/-1.63 months, respectively. Especially in terms of the 2-year survival rate, the high-dose group showed a much better survival time than the low-dose group; 44.7% versus 19.2%. Upon univariate analyses, age, performance status, location of tumor, extent of surgery, tumor volume and radiation dose group were significant factors for survival. Multivariate analyses confirmed that the impact of radiation dose on survival was independent of age, performance status, extent of surgery and target volume. During the follow-up period, complications related directly with radiation, such as radionecrosis, has not been identified. CONCLUSION: Using 3D-conformal radiotherapy, which is able to reduce the radiation dose to normal tissues compared to 2D-conventional treatment, up to 70 Gy of radiation could be delivered to the GTV without significant toxicity. As an approach to intensify local treatment, the radiation dose escalation through 3D-CRT can be expected to increase the overall and progression free survival times for patients with glioblastomas.

Analysis of the Causes of Subfrontal Recurrence in Medulloblastoma and Its Salvage Treatment / 대한방사선종양학회지

PURPOSE: Firstly, to analyze factors in terms of radiation treatment that might potentially cause subfrontal relapse in two patients who had been treated by craniospinal irradiation (CSI) for medulloblastoma. Secondly, to explore an effective salvage treatment for these relapses. MATERIALS AND METHODS: Two patients who had high-risk disease (T3bM1, T3bM3) were treated with combined chemoradiotherapy. CT-simulation based radiation-treatment planning (RTP) was performed. One patient who experienced relapse at 16 months after CSI was treated with salvage surgery followed by a 30.6 Gy IMRT (intensity modulated radiotherapy). The other patient whose tumor relapsed at 12 months after CSI was treated by surgery alone for the recurrence. To investigate factors that might potentially cause subfrontal relapse, we evaluated thoroughly the charts and treatment planning process including portal films, and tried to find out a method to give help for placing blocks appropriately between subfrotal-cribrifrom plate region and both eyes. To salvage subfrontal relapse in a patient, re-irradiation was planned after subtotal tumor removal. We have decided to treat this patient with IMRT because of the proximity of critical normal tissues and large burden of re-irradiation. With seven beam directions, the prescribed mean dose to PTV was 30.6 Gy (1.8 Gy fraction) and the doses to the optic nerves and eyes were limited to 25 Gy and 10 Gy, respectively. RESULTS: Review of radiotherapy portals clearly indicated that the subfrontal-cribriform plate region was excluded from the therapy beam by eye blocks in both cases, resulting in cold spot within the target volume. When the whole brain was rendered in 3-D after organ drawing in each slice, it was easier to judge appropriateness of the blocks in port film. IMRT planning showed excellent dose distributions (Mean doses to PTV, right and left optic nerves, right and left eyes: 31.1 Gy, 14.7 Gy, 13.9 Gy, 6.9 Gy, and 5.5 Gy, respectively. Maximum dose to PTV: 36 Gy). The patient who received IMRT is still alive with no evidence of recurrence and any neurologic complications for 1 year. CONCLUSION: To prevent recurrence of medulloblastoma in subfrontal-cribriform plate region, we need to pay close attention to the placement of eye blocks during the treatment. Once subfrontal recurrence has happened, IMRT may be a good choice for re-irradiation as a salvage treatment to maximize the differences of dose distributions between the normal tissues and target volume.

The Optimal Radiation Dose in Localized Head and Neck Diffuse Large Cell Lymphoma / 대한방사선종양학회지

PURPOSE: To determine the optimal radiation dose in a localized non-Hodgkin's lymphoma of the head and neck in the treatment setting for combined chemoradiotherapy. MATERIALS AND METHODS: Fifty-three patients with stage I and II diffuse large cell non-Hodgkin's lymphoma of the head and neck, who were treated with combined chemoradiotherapy between 1985 and 1998 were retrospectively reviewed. The median age was 49 years, and the male-to-female ratio was approximately 1.6. Twenty-seven patients had stage I disease and 26 had stage II. Twenty-three patients had bulky tumors (> or =5 cm) and 30 had non-bulky tumors ( or =5 cm. CONCLUSION: A dose of 30 Gy is sufficient for local control in patients with a non-bulky ( or =5 cm).

Meta Analysis for the Relation between Korean Dietary Factors and Stomach Cancer

BACKGROUND: The prevalence of stomach cancer had decreased in developed countries, but still remains high in Korea. There was an agreement that dietary factors were the most important factors in gastric carcinogenesis. We undertook a meta-analysis to verify the relation between Korean food items and stomach cancer. METHODS: We searched all studies compatible for meta-analysis by computer and by manual and found two studies. We analyzed 14 dietary factors presented in the two studies by Peto's method. We calculated summary odds ratios and test for homogeneity. RESULTS: Among the 14 dietary factors, salt preference (odds ratio 1.72 [95%CI 1.29-2.30] P<0.001), soybean paste stew (odds ratio 4.19 [95%CI 2.99-5.89] P<0.001), hot pepper soybean paste stew (odds ratio 1.96 [95%CI 1.45-2.64] P<0.001), Kimchi (odds ratio 2.05 [95%CI 1.43-2.94] P<0.001), meat/fish stew (odds ratio 1.58 [95%CI 1.17-2.13] P=0.003), Bulgogi/broiled fish (odds ratio 1.84 [95%CI 1.37-2.49] P<0.001), salted side dishes (odds ratio 1.96 [95%CI 1.47-2.61] P<0.001), and chemical seasoning (odds ratio 2.55 95%CI 1.62-4.02 P<0.001) were risk factors to gastric cancer. But mung bean pancake (odds ratio 0.2 [95%CI 0.14-0.31] P<0.001) Dubu (odds ratio 0.59 [95%CI 0.43-0.83] P=0.002), and garlic (odds ratio 0.45 [95%CI 0.32-0.63] P<0.001) were preventable factors against gastric cancer. Red pepper (odds ratio 1.21 [95%CI 0.91-1.63] P=0.19) and boiled rice (odds ratio 1.39 [95%CI 0.87-2.2] P=0.16) were risk factors to gastric cancer, and sesame oil preference (odds ratio 0.68 [95%CI 0.46-1.01] P=0.06) was a preventable factor against gastric cancer, but these results were not statistically significant.