[en] This study was performed for the evaluation of the feasibility and toxicity of hypofractionated radiation therapy for early glottic cancer. From February 1999 to February 2000, 20 patients with histologically confirmed Stage I, II glottic cancer were enrolled into this study. There were 18 males and 2 females, the median age of the patients was 59 years. The distribution of stage distribution was as follows; T1aN0-16 patients, T1bN0-1 patient, T2N0-3 patients. Eighteen patients underwent laryngomicroscopic biopsy only, and two patients underwent laser cordectomy. All patients received radical radiation therapy (2.5 Gy per fraction, 24 fractions, total 60 Gy). Median duration of treatment was 36 days. Radiation therapy were well tolerated. Most common acute reactions were odynophagia and hoarseness, and these reactions resolved after radiation therapy. There were one case of RTOG grade 3 odynophagia (5%), six cases of grade 3 hoarseness (30%). Response of radiation therapy was evaluated one month after completion of treatment. All patients revealed complete response. During follow up, total three cases of treatment failure were detected. two cases were local recurrence in 10 and 13 months of radiation therapy and one case was local recurrence and distant metastasis in 2 months of radiation therapy. This hypofractionated radiation therapy schedule was feasible and effective for control of early glottic cancer. But longer follow up time would be required to assess the long-term disease control and the late complication by shortening radiation therapy duration

[en] The objective of this study is to develop an algorithm for estimation of tumor dose using measured transmission dose as a part of the development of on-line dosimetry system. Data of transmission dose were measured under various FS, Tp and PCD with a special water phantom for 6 MV and 10 MV x-ray. SCD (source-chamber distance) was set to 150 cm. Measurements were conducted with a 0.125 cc ion chamber. Using measured data and regression analysis, two algorithms were developed for estimation of expected reading for measured data. Algorithm 1 consisted of the quadratic function of PCD and the tertiary function of A/P (area-perimeter ratio). Algorithm 2 consisted of the tertiary function of log(A/P) and the tertiary function of PCD. Algorithm 2 required less data set and was more accurate in comparing expected and observed dose. Using the algorithm developed, transmission dose can be estimated for any exposure condition, i.e. any given Tp, PCD and FS with high accuracy. To complete this algorithm, further developments are needed regarding the beam modifying device, the tissue inhomogeneity and the irregular body surface

[en] This paper provides a brief review of the advanced technologies for carbon ion radiotherapy (CIRT), with a focus on current developments. Compared to photon beam therapy, treatment using heavy ions, especially a carbon beam, has potential advantages due to its physical and biological properties. Carbon ion beams with high linear energy transfer demonstrate high relative biological effectiveness in cell killing, particularly at the Bragg peak. With these unique properties, CIRT allows for accurate targeting and dose escalation for tumors with better sparing of adjacent normal tissues. Recently, the available CIRT technologies included fast pencil beam scanning, super-conducting rotating gantry, respiratory motion management, and accurate beam modeling for the treatment planning system. These techniques provide precise treatment, operational efficiency, and patient comfort. Currently, there are 12 CIRT facilities worldwide; with technological improvements, they continue to grow in number. Ongoing technological developments include the use of multiple ion beams, effective beam delivery, accurate biological modeling, and downsizing the facility

[en] Purpose: The cyclooxygenase (COX)-2 enzyme has been shown to have an important role in carcinogenesis and apoptosis in various types of cancer. The purpose of this study was to evaluate the relationship between local recurrence or distant metastasis and COX-2 expression and apoptosis in cervical cancer patients treated with radical radiotherapy (RT). Methods and Materials: Twenty-two patients who were diagnosed with cervical cancer were enrolled in this study. All patients were treated with radical RT (external beam RT plus brachytherapy) at Seoul National University Hospital. The formalin-fixed, paraffin-embedded tissues of 11 patients who developed local recurrence (n=3) or distant metastasis (n=8) were compared with those of other patients who were disease free. Prognostic factors, including tumor size, lymph node metastatic status, and stage, were well balanced between the two groups. COX-2 expression was determined immunohistochemically, and apoptosis was assessed using in situ DNA nick end labeling (TUNEL)-based methods. Results: COX-2 expression was stronger in the local recurrence and distant metastasis patients than in those free of disease. COX-2 expression was shown to have a statistically significant influence on treatment failure by the Mann-Whitney U test (p=0.015) and the Mantel-Haenszel chi-square test (p=0.015), but its distribution did not correlate with apoptosis. Among the clinicopathologic factors, including stage, lymph node metastatic status, and tumor size, lymph node metastatic status was found to closely correlate with COX-2 expression by the Mann-Whitney U test (p=0.045) and Mantel-Haenszel chi-square test (p=0.065). Conclusion: COX-2 is believed to be one of the important factors associated with lymph node involvement and treatment failure. Our results suggest that inhibiting COX-2 may decrease treatment failure in cervical cancer treated with RT, and that COX-2 inhibitor administration may play an adjuvant role in cervical cancer treatment

[en] Rarity of olfactory neuroblastoma makes it difficult for treating physician to practice with a consistent protocol. This study is performed to analyze our experience with various treatment modalities for patients with olfactory neuroblastoma. Discussion includes review of some recently published literatures. Between June of 1979 and April of 1997, 20 patients were treated under the diagnosis of olfactory neuroblastoma at Seoul National University Hospital. There were 14 male and 6 female patients. Age at initial treatment ranged from 13 to 77 years with median of 24 years. Fifteen of 20 patients had Kadish stage C. They were treated with various combinations of surgery, radiation therapy and chemotherapy; surgery+postoperative radiation therapy+adjuvant chemotherapy for 2 patients, surgery+postoperative radiation therapy for 6, neoadjuvant chemotherapy+surgery for 1, surgery+adjuvant chemotherapy for 1, surgery only for 2, neoadjuvant chemotherapy+radiation therapy for 3, radiation therapy+adjuvant chemotherapy for 1, radiation therapy only for 3, and no treatment for 1 patient. Follow-up ranged from 2 month to 204 months with mean of 39.6 months. The overall 5- and 10-year survival rates are 20% and 10%, respectably. Four patients are alive at the time of data analysis. One of four living patients was treated with radical surgery, postoperative radiation therapy and adjuvant chemotherapy, two patients with radical surgery and postoperative radiation therapy, and one with radical surgery only. Multidisciplinary approach, including radical surgery, pre- or post-operative radiation therapy and chemotherapy, should be addressed at the initial time of diagnosis. Although limited by small number of the patients, this study suggests importance of local treatment modality, especially radical surgery in the treatment of olfactory neuroblastoma

[en] This study was undertaken to estimate the exposed dose of the medical personnel during the intracoronary radiotherapy procedure as a part of ongoing SPARE (Seoul National University Hospital Post-Angioplasty Rhenium) trial. Data of thirty-four patients among forty-two irradiated patients participating in this trial due to coronary artery stenosis were retrospectively analyzed. Intracoronary radiotherapy was delivered to the patient immediately after angioplasty ballooning. Prescribed dose was 17 Gy to media of the diseased artery and was delivered with ¹⁸⁸Re filled balloon catheter. Dosimetry was carried out with GM counter at eight different points. Ten centimeter and forty centimeter from the patient's heart were selected to represent maximum and whole-body exposed dose of the operator, respectively. Median delivered dose was 111.6 mCi with average treatment time of 576 seconds. Average exposed dose rate at 10 cm and 40 cm from the patient's heart were 0.43 mSv/hr and 0.30 mSv/hr, respectively. Average exposed dose per treatment were 0.07 mSv and 0.05 mSv for 10 cm and 40 cm from the patient's heart, respectively. Exposed doses measured are much lower than recommended limit of 50 mSv for radiation workers or 1 mSv for general population in ICRP-60. This study proves that current method of intracoronary radiotherapy incorporated in this trial is very safe regarding radiation protection

[en] We evaluated the effectiveness and safety of ipsilateral radiotherapy for the patient with well lateralized tonsil cancer: not cross midline and <1 cm of tumor invasion into the soft palate or base of tongue. From 2003 to 2011, twenty patients with well lateralized tonsil cancer underwent ipsilateral radiotherapy. Nineteen patients had T1-T2 tumors, and one patient had T3 tumor; twelve patients had N0-N2a disease and eight patients had N2b disease. Primary surgery followed by radiotherapy was performed in fourteen patients: four of these patients received chemotherapy. Four patients underwent induction chemotherapy followed by concurrent chemoradiotherapy (CCRT). The remaining two patients received induction chemotherapy followed by radiotherapy and definitive CCRT, respectively. No patient underwent radiotherapy alone. We analyzed the pattern of failure and complications. The median follow-up time was 64 months (range, 11 to 106 months) for surviving patients. One patient had local failure at tumor bed. There was no regional failure in contralateral neck, even in N2b disease. At five-year, local progression-free survival, distant metastasis-free survival, and progression-free survival rates were 95%, 100%, and 95%, respectively. One patient with treatment failure died, and the five-year overall survival rate was 95%. Radiation Therapy Oncology Group grade 2 xerostomia was found in one patient at least 6 months after the completion of radiotherapy. Ipsilateral radiotherapy is a reasonable treatment option for well lateralized tonsil cancer. Low rate of chronic xerostomia can be expected by sparing contralateral major salivary glands.

[en] The aim of this study is to investigate the delivery accuracy of intensity-modulated radiation therapy (IMRT) plans in the two-headed mode of the ViewRay^TM system in comparison with that of the normal operation treatment plan of the machine. For this study, a total of eight IMRT plans and corresponding verification plans were generated (four head and neck, two liver, and two prostate IMRT plans). The delivered dose distributions were measured using ArcCHECK^TM with the insertion of an ionization chamber. We measured the delivered dose distributions in three-headed mode (normal operation of the machine), two-headed mode with head 1 disabled, two-headed mode with head 2 disabled, and two-headed mode with head 3 disabled. Therefore, a total of four measurements were performed for each IMRT plan. The global gamma passing rates (3%/3 mm) in three-headed mode, head 1 disabled, head 2 disabled, and head 3 disabled were 99.9±0.1%, 99.8±0.3%, 99.6±0.7%, and 99.7±0.4%, respectively. The difference in the gamma passing rates of the three- and two-headed modes was insignificant. With 2%/2 mm, the rates were 96.6±3.6%, 97.2±3.5%, 95.7±6.2%, and 95.5±4.3%, respectively. Between three-headed mode and head 3 disabled, a statistically significant difference was observed with a p-value of 0.02; however, the difference was minimal (1.1%). The chamber readings showed differences of approximately 1% between three- and two-headed modes, which were minimal. Therefore, the treatment plan delivery in the two-headed mode of the ViewRay^TM system seems accurate and robust.

[en] This study was designed to examine the reliability of the new version of the AJCC staging system (1997) of nasopharyngeal carcinoma in comparison with the AJCC staging system of 1992. Between 1983 and 1996, 185 patients with histologically proven nasopharyngeal carcinoma were treated with radiation therapy at the Department of Therapeutic Radiology Seoul National University Hospital. For these patients, AJCC staging system of 1992 was compared with the 1997 version, by reviewing hospital records, computed tomography (CT) and/or magnetic resonance imaging (MRI). 5-year overall survival rates according to the 1992 and 1997 AJCC staging systems were 100%, and 100% at stage I; 100%, and 68.8% at stage ll;61.4%, and 63.8% at stage III; 61.1%, and 63.2% at stage IV. 5-year overall survival rates of each classification showed significant differences between stages (p=0.0049 for the old version, p=0.01 for the new), but no significant difference was found between the staging systems except at stage II. The new AJCC staging system allows staging as reliably as the 1992 version, but the adequacy of the newly modified staging classification should be confirmed by further clinical examination

[en] The incidence of esophageal carcinoma is increasing. Radical surgery is the treatment of choice, but large proportion of the esophageal cancer patients are with unresectable disease at the time of initial diagnosis, so radiation therapy has been the major treatment modality. We carried out retrospective analysis to see the outcome and prognostic factors of radiation therapy alone for esophageal carcinoma. From June of 1979 through December 1992, 289 patients with esophageal carcinoma were threated with radiation therapy alone at Department of Therapeutic Radiology, Seoul National University Hospital. Of these patients, 84 patients were excluded as they were ineligible for the current analyses. Twenty-two patients had distant metastasis other than supraclavicular lymph node metastasis, 52 patients received less than 45 Gy, and 10 patient were lost from follow-up. Therefore 205 patients constituted the base population of this study. According to AJCC staging system, there were 2 patients with stage I, 104 with stage IIA, 26 with stage IIB, 48 with stage III, and 25 with stage IV. Radiation dose ranged from 4500 cGy to 6980 cGy with median dose of 5940 cGy. Follow-up period of the alive patients ranged from 77 to 180 months. The median survival period of all the patients was 11 months and the 2-, 5-, and 10-year overall survival rates were 22.4%, 10.2% and 5.3%, respectively. Most of the failures were local recurrences. Of 169 failures, 134 had local failure as a component and 111 had local recurrence only. The Lymph node was most common distant metastatic site and the next was the lung. The stage, T-stage, N-stage, functional status, tumor size, and aim of treatment were statistically significant prognostic factors for survival by univariate analyses. But only tumor size and N-stage were significant by multivariate analyses. We could get 10.2% of 5 year survival rate and 5.3% of 10 year survival rate with radiation theraph alone. The size of tumor and N-stage were statistically significant prognostic factors for survival on multivariate analyses