The first private-hospital based proton therapy center in Korea; status of the Proton Therapy Center at Samsung Medical Center

PURPOSE: The purpose of this report is to describe the proton therapy system at Samsung Medical Center (SMC-PTS) including the proton beam generator, irradiation system, patient positioning system, patient position verification system, respiratory gating system, and operating and safety control system, and review the current status of the SMC-PTS. MATERIALS AND METHODS: The SMC-PTS has a cyclotron (230 MeV) and two treatment rooms: one treatment room is equipped with a multi-purpose nozzle and the other treatment room is equipped with a dedicated pencil beam scanning nozzle. The proton beam generator including the cyclotron and the energy selection system can lower the energy of protons down to 70 MeV from the maximum 230 MeV. RESULTS: The multi-purpose nozzle can deliver both wobbling proton beam and active scanning proton beam, and a multi-leaf collimator has been installed in the downstream of the nozzle. The dedicated scanning nozzle can deliver active scanning proton beam with a helium gas filled pipe minimizing unnecessary interactions with the air in the beam path. The equipment was provided by Sumitomo Heavy Industries Ltd., RayStation from RaySearch Laboratories AB is the selected treatment planning system, and data management will be handled by the MOSAIQ system from Elekta AB. CONCLUSION: The SMC-PTS located in Seoul, Korea, is scheduled to begin treating cancer patients in 2015.

High Dose Involved Field Radiation Therapy as Salvage for Loco-Regional Recurrence of Non-Small Cell Lung Cancer

PURPOSE: To determine the effectiveness of salvage radiation therapy (RT) in patients with loco-regional recurrences (LRR) following initial complete resection of non-small cell lung cancer (NSCLC) and assess prognostic factors affecting survivals. MATERIALS AND METHODS: Between 1994 and 2007, 64 patients with LRR after surgery of NSCLC were treated with high dose RT alone (78.1%) or concurrent chemo-radiation therapy (CCRT, 21.9%) at Samsung Medical Center. Twenty-nine patients (45.3%) had local recurrence, 26 patients (40.6%) had regional recurrence and 9 patients (14.1%) had recurrence of both components. The median RT dose was 54 Gy (range, 44-66 Gy). The radiation target volume included the recurrent lesions only. RESULTS: The median follow-up time from the start of RT in survivors was 32.0 months. The rates of in-field failure free survival, intra-thoracic failure free survival and extra-thoracic failure free survival at 2 years were 52.3%, 33.9% and 59.4%, respectively. The median survival after RT was 18.5 months, and 2-year overall survival (OS) rate was 47.9%. On both univariate and multivariate analysis, the interval from surgery till recurrence and CCRT were significant prognostic factors for OS. CONCLUSION: The current study demonstrates that involved field salvage RT is effective for LRR of NSCLC following surgery.

Dosimetry by Using EBT2 Film for Total Skin Electron Beam Therapy (TSET) / 의학물리

For treatment of Total Skin Electron beam Therapy (TSET), measurement of dose at various conditions is need on the contrary to usual radiotherapy. When treating TSET with modified Stanford technique based on linear accelerator, the energy of treatment electron beam, the spatial dose distribution and the actual doses deposited on the surface of the patient were measured by using EBT2. The measured energy of the electron beam was agreed with the value that measured by ionization chamber, and the spatial dose distribution at the patient position and the doses at several point on the patient's skin could be easily measured by EBT2 film. The dose on the patient that was measured by EBT2 film showed good agreement with the data measured simultaneously by TLD. With the results of this study, it was proven that the EBT2 film can be one of the useful dosimeter for TSET.

Evaluation of Parotid Gland Function following Intensity Modulated Radiation Therapy for Head and Neck Cancer / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: This study was undertaken to determine the parotid gland tolerance dose levels following intensity modulated radiation therapy (IMRT) for treating patients who suffered with head and neck cancer. MATERIALS AND METHODS: From February 2003 through June 2004, 34 head and neck patients with 6 months of follow-up were evaluated for xerostomia after being treated by IMRT. Their median age was 59 years (range: 29~78). Xerostomia was assessed using a 4-question xerostomia questionnaire score (XQS) and a test for the salivary flow rates (unstimulated and stimulated: USFR and SSFR, respectively). The patients were also given a validated LENT SOMA scale (LSS) questionnaire. Evaluations were performed before IMRT and at 1, 3 and 6 months after IMRT. RESULTS: All 34 patients showed significant changes in the XQS, LSS and Salivary Flow rates (USFR and SSFR) after IMRT. No significant changes in the XQS or LSS were noted in 12 patients who received a total parotid mean dose of 3,100 cGy, significant increases in the XQS and LSS were observed. The USFR and SSFR from the parotid glands in 7 patients who received 2,750 cGy were significantly lower than the baseline values at all times after IMRT. CONCLUSION: We suggest that the total parotid mean dose should be limited to < or =2,750 cGy to preserve the USFR and SSFR and so improve the subsequent quality of life.

Dosimetric Verification of Dynamic Conformal Arc Radiotherapy / 의학물리

The purpose of this study is to develop the optimization method for adjusting the film isocenter shift and to suggest the quantitative acceptable criteria for film dosimetry after optimization in the dynamic conformal arc radiation therapy (DCAR). The DCAR planning was performed in 7 patients with brain metastasis. Both absolute dosimetry with ion chamber and relative film dosimetry were performed throughout the DCAR using BrainLab's micro-multileaf collimator. An optimization method for obtaining the global minimum was used to adjust for the error in the film isocenter shift, which is the largest part of systemic errors. The mean of point dose difference between measured value using ion chamber and calculated value acquired from planning system was 0.51+/-0.43% and maximum was 1.14% with absolute dosimetry. These results were within the AAPM criteria of below 5%. The translation values of film isocenter shift with optimization were within +/-1 mm in all patients. The mean of average dose difference before and after optimization was 1.70+/-0.36% and 1.34+/-0.20%, respectively, and the mean ratios over 5% dose difference was 4.54+/-3.94% and 0.11+/-0.12%, respectively. After optimization, the dose differences decreased dramatically and a ratio over 5% dose difference and average dose difference was less than 2%. This optimization method is effective in adjusting the error of the film isocenter shift, which is the largest part of systemic errors, and the results of this research suggested the quantitative acceptable criteria could be accurate and useful in clinical application of dosimetric verification using film dosimetry as follows; film isocenter shift with optimization should be within +/-1 mm, and a ratio over 5% dose difference and average dose difference were less than 2%.

Gastrointestinal Stromal Tumor of Rectum: A Reoport of 7 Cases

PURPOSE: Gastrointestinal stromal tumors (GISTs) are rare. The aim of this study is to investigate and describe the clinicopathologic characteristics of rectal GISTs. METHODS: We retrospectively analyzed the medical records of seven patients who underwent surgery for GIST of the rectum from 1998 to 2003. RESULTS: Male and female patients were two and five respectively. The mean age was 55 years (range, 41~72 years) at the time of diagnosis. The median follow-up period was 23 months (range, 7~75 months). The chief complaints were hematochezia, constipation and anal pain. Curative resections were done in all cases. Abdominoperineal resection was done in five cases and transanal excision was done in one case. In one case, Hartmann's operation with prostatectomy was done. The mean size of tumor was 6.6 cm (1~12 cm). The pathologic feature of all cases were spindle cell type. The mitotic count shown > or =5 in 50 high power field was identified in four cases and that shown < or =5 in 50 high power field in three cases. Adjuvant radiation therapy was done in four cases. Two local recurrences occurred on 54 month and 23 month later after surgery, respectively. CONCLUSION: In cases of GIST of the rectum, the common symptom was same as other rectal tumors. Immuonhistiochemical staning of c-kit is helpful for differential diagnosis. Curative surgical resection should be done for treatment.

Evaluation of Xerostomia Following Intensity Modulated Radiotherapy (IMRT) for Head and Neck Cancer Patients / 대한방사선종양학회지

PURPOSE: This study was done to evaluate xerostomia following intensity modulated radiotherapy for patients with head and neck cancer, and to analyze the correlation between the dosimetric parameters and xerostomia parameters. MATERIALS AND MEHTODS: From February till October 2003, 13 patients with 3 months of follow-up were evaluated for xerostomia after being treated for head and neck cancer with IMRT. Their median age was 57 years (range: 43~77). Xerostomia were assessed with a 4-question xerostomia questionnaire score (XQS) and a test for salivary flow rates (unstimulated and stimulated). The patients were also given a validated LENT SOMA scale (LSC) questionnaire. The evaluations were completed before radiation therapy (pre-RT) and at 1 and, 3 months after radiation therapy (RT). We evaluated xerostomia at pre-RT, 1 and, 3 months after RT. The association between the xerostomia parameters (XQS and LSC) and salivary flow rates (unstimulated and stimulated: USFR and SSFR) was assessed at 1 and 3 months after RT. RESULTS: All 13 patients showed no significant changes in XQS, LSC and Salivary Flow rates. As a result, we couldn`t find out about xerostomia development. Based on the total mean parotid dose, 3,500 cGy, we divided these patients into two groups. The 8 patients ( or =3,500 cGy), there was a significant increase in USFR and, SSFR at 3 months after RT, and for the XQS and, LSC at 1 and 3 months after RT. The correlation between XQS and, LSC, and USFR and, SSFR in all patients (13) was significant at 3 months after RT. The correlation had a tendency to the decrease for USFR and, SSFR in proportion to the increase of XQS and, LSC. CONCLUSION: Based on the results of this study, IMRT seem to be an effective treatment to significantly decrease the xerostomia. XQS and, LSC seem to be a effective tool for predicting the xerostomia. A total parotid gland mean dose of <3,500 cGy should be a planning goal if substantial sparing of the gland function is desired. Furthermore, patients should be enrolled in a study to define a more accurate threshold dose for the parotid gland.

Analysis of Criteria for Tumor Response after Preoperative Chemoradiation Therapy for Locally Advanced Rectal Cancer: Correlation between Tumor Volume Reduction and Histopathologic Downstaging

PURPOSE: Preoperative chemoradiation treatment (CCRT) for locally advanced rectal cancer has been known to be safe and effective. The aim of study is to find any correlation between tumor volume reduction and histopathologic downstaging in locally advanced rectal cancer by preoperative CCRT. METHODS: A total of 16 patients of rectal cancer were selected. They had been T3,4 N (+) preoperatively staged by using a transrectal ultrasonography and pelvic MRI. Radiation was given, a total of 5,040 cGy over 5 weeks, and systemic chemotherapy was also given 5 FU 450 mg/m2 and leucovorin 20 mg/m2 concurrently intravenously during the first and the fifth week of CCRT. Surgery was done 4~6 weeks after completion of CCRT. A 3D CT image was obtained with AcQsim PQ 5000 3D (Philips, USA). Tumor volume was measured before and after CCRT. RESULTS: The type of operative procedures were abdominoperineal resection 7, low anterior resection 5, coloanal anastomosis 3 and Hartmann operation 1. Volume reduction was ranged from 14.6% to 84.4%. Over a 50% tumor volume reductions were in 9 patients (56.2%). Pathologic complete remission was observed in 2 patients (12.5%), who showed 72% and 58.5% tumor volume reductions. Patients showing pT and/or pN downstaging patients (N=9) had a 55.9% tumor reductions (14.6~84.4%), and patients showing no pT and/or pN downstaging (N=7) had 51.8% volume reduction (24.7~79%). CONCLUSIONS: Preoeperative CCRT has been thought to be able to decrease tumor size and volume and to increase respectability. However, among our 9 patients who showed over 50% tumor volume reductions, 3 patients did not show any T and N downstaging, which is really important for long-term oncologic outcomes.

Combined Chemotherapy and Radiotherapy versus Radiotherapy alone in the Management of Localized Angiocentric Lymphoma of the Head and Neck / 대한방사선종양학회지

PURPOSE: To clarify the clinical benefit derived from the combined modality therapy (CMT) consisting of chemotherapy (CT) and involved field radiotherapy (RT) for stage I and II angiocentric lymphomas of the head and neck. MATERIALS AND METHODS: Of 143 patients with angiocentric lymphoma of the head and neck treated at our hospital between 1976 and 1995, 104 patients (RT group) received involved field RT alone with a median dose of 50.4 Gy (range : 20-70 Gy), while 39 patients (CMT group) received a median 3 cycles (range : 1-6 cycles) of CT before involved field RT. The response rate, patterns of failure, complications, and survival data of the RT group were compared with those of the CMT group. RESULTS: Despite a higher response rate, local failure was the most common pattern of failure in patients of both groups. The patterns of failure, including the systemic relapse rate were not influenced by the addition of combination CT. Although both modalities were well tolerated by the majority of patients, aberrant immunologic disorders or medical illnesses, such as a hemophagocytic syndrome, sepsis, intractable hemorrhage, or the evolution of second primary malignancies were more frequently observed in patients of the CMT group. The prognosis of patients in the RT group was relatively poor, with a 5-year overall actuarial survival rate of 38% and disease-free survival rate of 32%, respectively. However, their clinical outcome was not altered by the addition of systemic CT. Achieving complete remission was the most important prognostic factor by univariate and multivariate analyses, but treatment modality was not found to be a prognostic variable influencing survival. Conclusions : Involved field RT alone for angiocentric lymphoma of the head and neck was insufficient to achieve an improved survival rate, but the addition of CT to involved field RT failed to demonstrate any therapeutic advantage over involved field RT alone.

Bladder Preservation by Combuned Modality Therapy for Invasive Bladder Cancer: A Five-Year Follow-up / 대한방사선종양학회지

No absract available.

Effect of Small Dose of Radiation on Induction of Apoptosis in Murine Tumors / 대한방사선종양학회지

PURPOSE: To investigate the presence of adaptive response by low dose radiation in murine tumors in relation to radiation induced apoptosis as well as related mechanism. MATERIALS AND METHODS: Syngeneic murine tumors, OCa-I and HCa-I, were given 0.05 Gy pretreatment followed by therapeutic dose of 25 Gy radiation. Induction of apoptosis was analyzed for each treatment group. Regulating molecules of apoptosis, p53, Bcl-2, Bax, Bcl-X, were also analyzed by Western blotting. RESULTS: In 0.05 Gy pretreatment group of OCa-I, 25 Gy-induced apoptosis per 1000 cells was 229, which was estimated at 30% lower level than the expected (p<0.05). In contrast, this reduction in radiation induced apoptosis was not seen in HCa-I. In the expression of apoptosis regulating molecules, p53 increased in both tumors in response to radiation. Bcl-2 and Bax did not show significant change in both tumors however, the expression of Bcl-2 surpassed that of Bax in 0.05 Gy pretreatment group of OCa-I. Bcl-X was not expressed in OCa-I. In HCa-I, Bcl-X showed increased expression even with 0.05 Gy. CONCLUSION: Adaptive response by low dose radiation is shown in one murine tumor, OCa-I, in relation to radiation induced apoptosis. Apoptosis regulating molecules including Bcl-2/Bax and Bcl-X, appear to related. This study shows an evidence that adaptive response is present, but not a generalized phenomenon in vivo.

Analysis of the Payment Rates and Classification of Services on Radiation Oncology / 대한치료방사선과학회지

PURPOSE: The main purpose of this study is to develop new payment rates for services of Radiation Oncology, considering costs of treating patients. MATERIAL AND METHODS: A survey of forty hospitals has been conducted in order to analyze the costs of treating patients. Before conducting the survey, we evaluated and reclassified the individual service items currently using as payments units on the fee-for-service reimbursement system. This study embodies the analysis of replies received from the twenty four hospitals. The survey contains informations about the hospitals' costs of 1995 for the reclassified service items on Radiation Oncology. After we adjust the hospital costs by the operating rate of medical equipment, we compare the adjusted costs with the current payment rates of individual services. RESULTS: The current payment rates were 5.05-6.58 times lower than the adjusted costs in treatment planning services, 2.22 times lower in block making service, 1.57-2.86 times lower in external beam irradiation services, 3.82-5.01 times lower in intracavitary and interstitial irradiation and 1.12- 2.55 times lower in total body irradiation. CONCLUSION: We could conclude that the current payment system on Radiation Oncology does not only reflect the costs of treating patients appropriately but also classify the service items correctly. For an example, when the appropriate costs and classification are applied to TBI, the payment rates of TBI should be increased five times more than current level.

Multimodal Approaches in the Patients with Stage I, II non-Hodgkin's Lymphoma of the Head and Neck / 대한치료방사선과학회지

PURPOSE: Traditionally the patients with early stage non-Hodgkin's lymphoma of he head and neck was treated with radiotherapy. But the results were not satisfactory due to distant relapse. Although combined treatment with radiotherapy and chemotherapy was tried with some improved results and chemotherapy alone was also tried in recent years, the choice of treatment for the patients with early stage non-Hodgkin's lymphoma of the head and neck has not been defined. Therfore, in order to determine the optimum treatment method, we analysed retrospectively the outcomes of the patients with Ann Arbor stage I and II non-Hodgkin's lymphoma localized to the head and neck who were treated at Serverance Hospital. MATERIALS AND METHODS: 159 patients with stage I and II non-hodgkin's lymphoma localized to the head and neck were treated at our hospital from January, 1979 to December, 1992. Of these patients, 114 patients whose primary sites were Waldeyer's ring or nodal region, and received prescribed radiation dose and/or more than 2 cycles of chemotherapy, were selected to analyze the outcomes according to the treatment methods (radiotherapy alone, chemotherapy alone, and combined treatment with radiotherapy and chemotherapy). RESULTS: Five year overall actuarial survival of the patients whose primary site was Waldeyer's ring was 62.5%, and that of the patients whose primary site was nodal region was 53.8%. There was no statistically significant difference between survivals of both groups. Initial response rate to radiotherapy, chemotherapy, and combined treatment was 92%, 83%, 94% respectively, and 5 year relapse free survival was 49.9%, 52.4%, 58.5% respectively (statistically no significant). In the patients with stage I, 3 year relapse free survival of chemotherapy alone group was 75% and superior to other treatment groups. In the patients with stage II, combined treatment group revealed the best result with 60.1% of 3 year relapse free survival. The effect of sequential schedule of each treatment method in the patients who were treated by combined modality was analyzed and the sequence of primary chemotherapy + radiotherapy + maintenance chemotherapy shoed the best result (3 year relapse free survival was 79.1%). There was no significant survival difference between BACOP regimen and CHOP regimen. Response to treatment was only one significant (p<0.005) prognostic factor on univariate analysis and age and mass size was marginally significant (p<0.01). On multivariate analysis, age (p=0.026) and mass size (p=0.013) were significant prognostic factor for the relapse free survival. CONCLUSION: In summary, the patients who have non-Hodgkin's lymphoma of the head and neck with stage I and mass size smaller that 10cm , can be treated by chemotherapy alone, but remainder should be treated by combined treatment method and the best combination schedule was the sequence of initial chemotherapy followed by radiotherapy and maintenance chemotherapy.

The Role of the Postoperative Adjuvant Radiation Therapy to Primary Site in Rectal Cancer Patients with Synchronous Liver Metastasis / 대한치료방사선과학회지

Among the patients with rectal cancer who entered Yonsei University Hospital for management from Jan. 1980 to Dec. 1990, we selected 23 subjects who were received surgical resection of tumor in rectum, and who proved to have liver metastasis during the diagnostic work-up, at the time of the operation, or within 3 months after starting definitive treatment. With those subjects, we investigated the role of radiation therapy by comparison of the treatment results of the patients without radiation therapy (S group) with those of the patients with radiation therapy to the primary site (S+R group). The local control rates of S group and S+R group were 64% and 89%, and 2-year survival rates were 50% and 78%, respectively. Although there was not statistically meaningful difference, local control rate and 2-year survival rate were higher in the group with radiation therapy to primary site than that without radiation therapy. The 2-year survival rates of the case with resection of the liver and the case without it were 03.6% and 58.3% respectively, which was not statistically significant. Also, the 2-year survival rate of the case with sustained local control was higher than that of the case with local failure, which was statistically significant(70.5% and 16.7%, p<0.005). From the above results, it is thought that radiation therapy to the primary site might improve the local control rate even in the patients with liver metastasis, which seems to be correlated to the higher survival rate.