Outcome of postoperative radiotherapy following radical prostatectomy: a single institutional experience

PURPOSE: This single institutional study is aimed to observe the outcome of patients who received postoperative radiotherapy after radical prostatectomy. MATERIALS AND METHODS: A total of 59 men with histologically identified prostate adenocarcinoma who had received postoperative radiation after radical prostatectomy from August 2005 to July 2011 in Seoul St. Mary's Hospital of the Catholic University of Korea, was included. They received 45-50 Gy to the pelvis and boost on the prostate bed was given up to total dose of 63-72 Gy (median, 64.8 Gy) in conventional fractionation. The proportion of patients given hormonal therapy and the pattern in which it was given were analyzed. Primary endpoint was biochemical relapse-free survival (bRFS) after radiotherapy completion. Secondary endpoint was overall survival (OS). Biochemical relapse was defined as a prostate-specific antigen level above 0.2 ng/mL. RESULTS: After median follow-up of 53 months (range, 0 to 104 months), the 5-year bRFS of all patients was estimated 80.4%. The 5-year OS was estimated 96.6%. Patients who were given androgen deprivation therapy had a 5-year bRFS of 95.1% while the ones who were not given any had that of 40.0% (p < 0.01). However, the statistical significance in survival difference did not persist in multivariate analysis. The 3-year actuarial grade 3 chronic toxicity was 1.7% and no grade 3 acute toxicity was observed. CONCLUSION: The biochemical and toxicity outcome of post-radical prostatectomy radiotherapy in our institution is favorable and comparable to those of other studies.

High-Dose-Rate Brachytherapy for the Treatment of Vaginal Intraepithelial Neoplasia / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Vaginal intraepithelial neoplasia (VAIN), a rare premalignant condition, is difficult to eradicate. We assess the effectiveness of high-dose rate intracavitary brachytherapy (HDR-ICR) in patients with VAIN or carcinoma in situ (CIS) of the vagina after hysterectomy. MATERIALS AND METHODS: We reviewed 34 patients treated for posthysterectomy VAIN or CIS of the vagina by brachytherapy as the sole treatment. All patients underwent a coloposcopic-directed punch biopsy or had abnormal cytology, at least 3 consecutive times. All patients were treated with a vaginal cylinder applicator. The total radiation dose was mainly 40 Gy in 8 fractions during the periods of 4 weeks at a prescription point of the median 0.2 cm (range, 0 to 0.5 cm) depth from the surface of the vaginal mucosa. RESULTS: Acute toxicity was minimal. Seven patients had grade 1/2 acute urinary and rectal complications. There were 15 cases of late toxicity, predominantly vaginal mucosal reaction in 12 patients. Of these patients, two patients suffered from grade 3 vaginal stricture and dyspareunia continuously. After a median follow-up time of 48 months (range, 4 to 122 months), there were 2 recurrences and 2 persistent diseases, in which a second-line therapy was needed. The success rate was 88.2%. The average prescription point in failure patients was 1.1 mm from the surface of the vagina compared to an average of 2.6 mm in non-recurrent patients (p=0.097). CONCLUSION: HDR-ICR is an effective treatment method in VAIN patients. In spite of high cure rates, we should consider issues regarding vaginal toxicity and radiation techniques to reduce the occurrence of failure and toxicity.

High-Dose-Rate Brachytherapy for the Treatment of Vaginal Intraepithelial Neoplasia / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Vaginal intraepithelial neoplasia (VAIN), a rare premalignant condition, is difficult to eradicate. We assess the effectiveness of high-dose rate intracavitary brachytherapy (HDR-ICR) in patients with VAIN or carcinoma in situ (CIS) of the vagina after hysterectomy. MATERIALS AND METHODS: We reviewed 34 patients treated for posthysterectomy VAIN or CIS of the vagina by brachytherapy as the sole treatment. All patients underwent a coloposcopic-directed punch biopsy or had abnormal cytology, at least 3 consecutive times. All patients were treated with a vaginal cylinder applicator. The total radiation dose was mainly 40 Gy in 8 fractions during the periods of 4 weeks at a prescription point of the median 0.2 cm (range, 0 to 0.5 cm) depth from the surface of the vaginal mucosa. RESULTS: Acute toxicity was minimal. Seven patients had grade 1/2 acute urinary and rectal complications. There were 15 cases of late toxicity, predominantly vaginal mucosal reaction in 12 patients. Of these patients, two patients suffered from grade 3 vaginal stricture and dyspareunia continuously. After a median follow-up time of 48 months (range, 4 to 122 months), there were 2 recurrences and 2 persistent diseases, in which a second-line therapy was needed. The success rate was 88.2%. The average prescription point in failure patients was 1.1 mm from the surface of the vagina compared to an average of 2.6 mm in non-recurrent patients (p=0.097). CONCLUSION: HDR-ICR is an effective treatment method in VAIN patients. In spite of high cure rates, we should consider issues regarding vaginal toxicity and radiation techniques to reduce the occurrence of failure and toxicity.

Comparison between preoperative and postoperative concurrent chemoradiotherapy for rectal cancer: an institutional analysis

PURPOSE: To evaluate the treatment outcomes of preoperative versus postoperative concurrent chemoradiotherapy (CRT) on locally advanced rectal cancer. MATERIALS AND METHODS: Medical data of 114 patients with locally advanced rectal cancer treated with CRT preoperatively (54 patients) or postoperatively (60 patients) from June 2003 to April 2011 was analyzed retrospectively. 5-Fluorouracil (5-FU) or a precursor of 5-FU-based concurrent CRT (median, 50.4 Gy) and total mesorectal excision were conducted for all patients. The median follow-up duration was 43 months (range, 16 to 118 months). The primary end point was disease-free survival (DFS). The secondary end points were overall survival (OS), locoregional control, toxicity, and sphincter preservation rate. RESULTS: The 5-year DFS rate was 72.1% and 48.6% for the preoperative and postoperative CRT group, respectively (p = 0.05, the univariate analysis; p = 0.10, the multivariate analysis). The 5-year OS rate was not significantly different between the groups (76.2% vs. 69.0%, p = 0.23). The 5-year locoregional control rate was 85.2% and 84.7% for the preoperative and postoperative CRT groups (p = 0.98). The sphincter preservation rate of low-lying tumor showed significant difference between both groups (58.1% vs. 25.0%, p = 0.02). Pathologic tumor and nodal down-classification occurred after the preoperative CRT (53.7% and 77.8%, both p < 0.001). Acute and chronic toxicities were not significantly different between both groups (p = 0.10 and p = 0.62, respectively). CONCLUSION: The results confirm that preoperative CRT can be advantageous for improving down-classification rate and the sphincter preservation rate of low-lying tumor in rectal cancer.

Treatment outcome in patients with vulvar cancer: comparison of concurrent radiotherapy to postoperative radiotherapy

PURPOSE: To evaluate outcome and morbidity in patients with vulvar cancer treated with radiotherapy, concurrent chemoradiotherapy or postoperative radiotherapy. MATERIALS AND METHODS: The records of 24 patients treated with radiotherapy for vulvar cancer between July 1993 and September 2009 were retrospectively reviewed. All patients received once daily 1.8-4 Gy fractions external beam radiotherapy to median 51.2 Gy (range, 19.8 to 81.6 Gy) on pelvis and inguinal nodes. Seven patients were treated with primary concurrent chemoradiotherapy, one patient was treated with primary radiotherapy alone, four patients received palliative radiotherapy, and twelve patients were treated with postoperative radiotherapy. RESULTS: Twenty patients were eligible for response evaluation. Response rate was 55% (11/20). The 5-year disease free survival was 42.2% and 5-year overall survival was 46.2%, respectively. Fifty percent (12/24) experienced with acute skin complications of grade III or more during radiotherapy. Late complications were found in 8 patients. 50% (6/12) of patients treated with lymph node dissection experienced severe late complications. One patient died of sepsis from lymphedema. However, only 16.6% (2/12) of patients treated with primary radiotherapy developed late complications. CONCLUSION: Outcome of patients with vulvar cancer treated with radiotherapy showed relatively good local control and low recurrence. Severe late toxicities remained higher in patients treated with both node dissection and radiotherapy.

The role of postoperative pelvic radiation in stage IV rectal cancer after resection of primary tumor

PURPOSE: To evaluate the effect of pelvic radiotherapy (RT) in patients with stage IV rectal cancer treated with resection of primary tumor with or without metastasectomy. MATERIALS AND METHODS: Medical records of 112 patients with stage IV rectal cancer treated with resection of primary tumor between 1990 and 2011 were retrospectively reviewed. Fifty-nine patients received synchronous or staged metastasectomy whereas fifty-three patients did not. Twenty-six patients received pelvic radiotherapy. RESULTS: Median overall survival (OS), locoregional recurrence-free survival (LRFS), and progression-free survival (PFS) of all patients was 27, 70, and 11 months, respectively. Pathologic T (pT), N (pN) classification and complete metastasectomy were statistically significant factors in OS (p = 0.040, 0.020, and 0.002, respectively). RT did not improve OS or LRFS. There were no significant factors in LRFS. pT and pN classification were also significant prognostic factors in PFS (p = 0.010 and p = 0.033, respectively). In the subgroup analysis, RT improved LRFS in patients with pT4 disease (p = 0.026). The locoregional failure rate of the RT group and the non-RT group were 23.1% and 33.7%, showing no difference in the failure pattern of both groups (p = 0.260). CONCLUSION: Postoperative pelvic RT did not improve LRFS of all metastatic rectal cancer patients; however, it can be recommended to patients with pT4 disease. A complete resection of metastatic masses should be performed if possible.

ERRATUM: Correction for Mistyped Inequality Sign / Journal of the Korean Cancer Association, 대한암학회지

No abstract available.

The Pathological and Clinical Effects of Preoperative Chemoradiation in Rectal Cancer / 대한방사선종양학회지

PURPOSE: To evaluate the pathological and clinical effects of preoperative chemoradiation (CCRT) in cases of locally advanced rectal cancer and to determine the predictive factors for tumor downstaging. MATERIALS AND METHODS: From March 2004 to August 2008, 33 patients with locally advanced rectal cancer were treated with preoperative CCRT. Twenty-eight patients (84.8%) were treated using a concomitant boost technique while five (15.2%) patients were treated using a cone down boost technique. All patients received 50.4 Gy of irradiation and concurrent chemotherapy with 5-fluorouracil. The median follow-up duration was 24.2 months (range, 9.8 to 64.7 months). RESULTS: Thirty-one (93.9%) patients underwent surgery. Twenty-four patients (72.7%) underwent anal sphincter-preserving surgery. The 3-year disease free survival (DFS) and overall survival rates were 63.4% and 78.8%, respectively. Post-operative factors were more important for DFS. Pathologic N stage, margin status, and pathologic differentiation were significant prognostic factors (p=0.001, 0.029, 0.030). Tumor size and lymphovascular invasion were also associated with marginal significance (p=0.081, 0.073). However, only pre-treatment T stage was a significant pre-operative factor (p=0.018). The complete pathological response rate was 9.1%. T-downstaging was observed in ten (30.3%) patients, whereas N-downstaging was found in 24 (72.7%) patients. Pre-treatment T stage and the interval between CCRT and operation were the predictive factors for downstaging in a univariate analysis (p=0.029, 0.027). Pre-treatment carcinoembryogenic antigen was also associated with marginal significance (p=0.068). CONCLUSION: The survival of rectal cancer patients can be better determined based on post-operative findings. Therefore, pre-operative CCRT for downstaging of the tumor seems to be important. Pre-treatment T stage and the interval between CCRT and operation can be used to predict downstaging.

Clinical Responses and Prognostic Indicators of Concurrent Chemoradiation for Non-small Cell Lung Cancer / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: To evaluate treatment outcomes and prognostic factors in non-small cell lung cancer (NSCLC) patients treated with concurrent chemoradiation. MATERIALS AND METHODS: From January 2005 to June 2009, 51 patients were treated with concurrent chemoradiation for 3 different aims: locally advanced stage III, locally recurrent disease, and postoperative gross residual NSCLC. Median age was 63 years. Distribution of stages by the 6th edition of American Joint Committee on Cancer (AJCC) was as follows: IIIA (37.3%), IIIB (56.9%). Chemotherapy was administered every week concurrently with radiation using one of the following regimens: paclitaxel (60 mg/m2), docetaxel+cisplatin (20 mg/m2+20 mg/m2), cisplatin (30 mg/m2). Total radiation dose was 16-66.4 Gy (median, 59.4 Gy). RESULTS: Median follow-up duration was 40.8 months. The overall response rate was 84.3% with 23 complete responses. The median survival duration for the overall patient group was 17.6 months. The 3-year survival rate was 17.8%. A total of 21 patients had recurrent disease at the following sites: loco-regional sites (23.6%), distant organs (27.5%). In the multivariate analysis of the overall patient group, a clinical tumor response (p=0.002) was the only significant prognostic factor for overall survival (OS). In the multivariate analysis of the definitive chemoradiation arm, the use of consolidation chemotherapy (p=0.022), biologically equivalent dose (BED)10 (p=0.007), and a clinical tumor response (p=0.030) were the significant prognostic factors for OS.The median survival duration of the locally recurrent group and the postoperative gross residual group were 26.4 and 23.9 months, respectively. CONCLUSION: Our study demonstrated that clinical tumor response was significantly associated with OS in the overall patient group. Further investigations regarding the optimal radiation dose in the definitive chemoradiation and the optimal treatment scheme in locally recurrent NSCLC would be required.

Clinical Responses and Prognostic Indicators of Concurrent Chemoradiation for Non-small Cell Lung Cancer / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: To evaluate treatment outcomes and prognostic factors in non-small cell lung cancer (NSCLC) patients treated with concurrent chemoradiation. MATERIALS AND METHODS: From January 2005 to June 2009, 51 patients were treated with concurrent chemoradiation for 3 different aims: locally advanced stage III, locally recurrent disease, and postoperative gross residual NSCLC. Median age was 63 years. Distribution of stages by the 6th edition of American Joint Committee on Cancer (AJCC) was as follows: IIIA (37.3%), IIIB (56.9%). Chemotherapy was administered every week concurrently with radiation using one of the following regimens: paclitaxel (60 mg/m2), docetaxel+cisplatin (20 mg/m2+20 mg/m2), cisplatin (30 mg/m2). Total radiation dose was 16-66.4 Gy (median, 59.4 Gy). RESULTS: Median follow-up duration was 40.8 months. The overall response rate was 84.3% with 23 complete responses. The median survival duration for the overall patient group was 17.6 months. The 3-year survival rate was 17.8%. A total of 21 patients had recurrent disease at the following sites: loco-regional sites (23.6%), distant organs (27.5%). In the multivariate analysis of the overall patient group, a clinical tumor response (p=0.002) was the only significant prognostic factor for overall survival (OS). In the multivariate analysis of the definitive chemoradiation arm, the use of consolidation chemotherapy (p=0.022), biologically equivalent dose (BED)10 (p=0.007), and a clinical tumor response (p=0.030) were the significant prognostic factors for OS.The median survival duration of the locally recurrent group and the postoperative gross residual group were 26.4 and 23.9 months, respectively. CONCLUSION: Our study demonstrated that clinical tumor response was significantly associated with OS in the overall patient group. Further investigations regarding the optimal radiation dose in the definitive chemoradiation and the optimal treatment scheme in locally recurrent NSCLC would be required.

Radiation-induced brain injury: retrospective analysis of twelve pathologically proven cases

PURPOSE: This study was designed to determine the influencing factors and clinical course of pathologically proven cases of radiation-induced brain injury (RIBI). MATERIALS AND METHODS: The pathologic records of twelve patients were reviewed; these patients underwent surgery following radiotherapy due to disease progression found by follow-up imaging. However, they were finally diagnosed with RIBI. All patients had been treated with 3-dimensional conventional fractionated radiotherapy and/or radiosurgery for primary or metastatic brain tumors with or without chemotherapy. The histological distribution was as follows: two falx meningioma, six glioblastoma multiform (GBM), two anaplastic oligodendroglioma, one low grade oligodendroglioma, and one small cell lung cancer with brain metastasis. RESULTS: Radiation necrosis was noted in eight patients and the remaining four were diagnosed with radiation change. Gender (p = 0.061) and biologically equivalent dose (BED)3 (p = 0.084) were the only marginally influencing factors of radiation necrosis. Median time to RIBI was 7.3 months (range, 0.5 to 61 months). Three prolonged survivors with GBM were observed. In the subgroup analysis of high grade gliomas, RIBI that developed or =6 months (p = 0.085). CONCLUSION: Our study demonstrated that RIBI could occur in early periods after conventional fractionated brain radiotherapy within normal tolerable dose ranges. Studies with a larger number of patients are required to identify the strong influencing factors for RIBI development.

FDG-PET/CT as prognostic factor and surveillance tool for postoperative radiation recurrence in locally advanced head and neck cancer

PURPOSE: To evaluate the prognostic value of metabolic tumor volume (MTV) and maximum standardized uptake value (SUVmax) on initial positron emission tomography-computed tomography (PET-CT) and investigate the clinical value of SUVmax for early detection of locoregional recurrent disease after postoperative radiotherapy in patients with locally advanced head and neck squamous cell carcinoma (HNSCC). MATERIALS AND METHODS: A total of 100 patients with locally advanced HNSCC received primary tumor excision and neck dissection followed by adjuvant radiotherapy with or without chemotherapy. The MTV and SUVmax were measured from primary sites and neck nodes. The prognostic value of MTV and SUVmax were assessed using initial staging PET/CT (study A). Follow-up PET/CT scan available after postoperative concurrent chemoradiotherapy or radiotherapy were evaluated for the SUVmax value and correlated with locoregional recurrence (study B). A receiver operating characteristic (ROC) curve analysis was used to define a threshold value of SUVmax with the highest accuracy for recurrent disease assessment. RESULTS: High MTV (>41 mL) is negative prognostic factor for disease free survival (p = 0.041). Postradiation SUVmax was significantly correlated with locoregional recurrence (hazard ratio, 1.812; 95% confidence interval, 1.361 to 2.413; p < 0.001). A cut-off value of 5.38 from follow-up PET/CT was identified as having maximal accuracy for detecting locoregional recurrence by ROC analysis. CONCLUSION: MTV at staging work-up was significantly associated with disease free survival. The SUVmax value from follow-up PET/CT showed high diagnostic accuracy for the detection of locoregional recurrence in postoperatively irradiated HNSCC.

Precision Validation of Electromagnetic Physics in Geant4 Simulation for Proton Therapy / 의학물리

Geant4 (GEometry ANd Tracking) provides various packages specialized in modeling electromagnetic interactions. The validation of Geant4 physics models is a significant issue for the applications of Geant4 based simulation in medical physics. The purpose of this study is to evaluate accuracy of Geant4 electromagnetic physics for proton therapy. The validation was performed both the Continuous slowing down approximation (CSDA) range and the stopping power. In each test, the reliability of the electromagnetic models in a selected group of materials was evaluated such as water, bone, adipose tissue and various atomic elements. Results of Geant4 simulation were compared with the National Institute of Standards and Technology (NIST) reference data. As results of comparison about water, bone and adipose tissue, average percent difference of CSDA range were presented 1.0%, 1.4% and 1.4%, respectively. Average percent difference of stopping power were presented 0.7%, 1.0% and 1.3%, respectively. The data were analyzed through the kolmogorov-smirnov Goodness-of-Fit statistical analysis test. All the results from electromagnetic models showed a good agreement with the reference data, where all the corresponding p-values are higher than the confidence level alpha=0.05 set.

Radiation Therapy Combined with (or without) Cisplatin-based Chemotherapy for Patients with Nasopharyngeal Cancer: 15-years Experience of a Single Institution in Korea / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: This retrospective study was carried out to evaluate the efficacy and toxicity of radiation therapy (RT) with/without cisplatin-based chemotherapy in nasopharyngeal cancer (NPC). MATERIALS AND METHODS: One hundred forty six patients with NPC received curative RT and/or cisplatin-based chemotherapy. Thirty-nine patients were treated with induction chemotherapy (IC), including cisplatin and 5-fluorouracil followed by RT. Another 63 patients were treated with concurrent chemoradiotherapy (CCRT) using cisplatin, and 22 patients were treated with IC followed by CCRT. The remaining 22 patients were treated with RT alone. RESULTS: One hundred four (80.0%) patients achieved complete response (CR), and 23 (17.7%) patients achieved partial response (PR). The patterns of failure were: locoregional recurrences in 21.2% and distant metastases in 17.1%. Five-year overall survival (OS) and progression free survival (PFS) were 50.7% and 45.0%, respectively. Multivariate Cox stepwise regression analysis revealed CR to chemoradiotherapy to be a powerful prognostic factor for OS. CR to chemoradiotherapy and completion of radiation according to the time schedule were favorable prognostic factors for PFS. A comparison of each treatment group (IC --> RT vs. CCRT vs. IC --> CCRT vs. RT alone) revealed no significant differences in the OS or PFS. However, subgroup analysis showed significant differences in both OS and DFS in favor of the combined chemoradiotherapy group compared with RT alone, for stage IV and T3-4 tumors. Grade 3-4 toxicities were more common in the combined chemoradiotherapy arm, particularly in the CCRT group. CONCLUSIONS: This study was limited in that it was a retrospective study, much time was required to collect patients, and there were imbalances in the number of patients in each treatment group. Combined chemoradiotherapy remarkably prolonged the OS and PFS in subgroup patients with stage IV or T3-4 NPC.

EGFR, p53, Cox-2 and Bcl-2 Expression in Nasopharyngeal Carcinoma and Their Potential Clinical Implication / 대한방사선종양학회지

PURPOSE: To evaluate the relationship between the expression of EGFR, p53, Cox-2, Bcl-2 and the clinical parameters of NPC (nasopharyngeal carcinoma) patients treated with radiotherapy with/without chemotherapy, and to determine if these could be used as a biologic marker. MATERIALS AND METHODS: This study retrospectively examined 75 NPC patients who were pathologically diagnosed at St. Mary's Hospital and Kangnam St Mary's Hospital from March 1988 to August 2002 and treated with radiotherapy with/without chemotherapy. The levels of EGFR, p53, Cox-2, and Bcl-2 expression were determined immunohistochemically. The relationship between the levels of EGFR, p53, Cox-2 and Bcl-2 expression and the H-E staining findings including the WHO classification, TNM stage, tumor response to chemotherapy and radiotherapy, disease free survival (DFS), and overall survival (OS) was analyzed. RESULTS: At a median follow up of 50.8 months (range: 5.5~201 months), the 3 years OS rate and PFS rate were 68.7% and 68.2%, respectively. The five year OS rate and PFS rate were 53.5% and 51.1%, respectively. The median OS duration and PFS duration were 85.5 months and 61.1 months, respectively. The WHO classification correlated with the complete response rate, lymph node metastasis and distant metastasis. The expression of p53 was associated with increased mitosis and poor overall survival. The expression of Bcl-2 correlated with the DFS and WHO classification. The expression of Cox-2 correlated with a poor overall survival and response rate in the lymph node. However, EGFR was not correlated with any factors. CONCLUSION: These results suggest that the expression of p53, Cox-2, Bcl-2 plays role in predicting prognostic factors for NPC treated with radiotherapy with/without chemotherapy. However, further study on a larger number of patients will be needed to identify more useful biomarkers of NPC.

Radiation Response Modulation of GW572016 (EGFR/HER2 Dual Tyrosine Kinase Inhibitor) in Human Breast Cancer Xenografts / 대한방사선종양학회지

PURPOSE: We examined the effect of the dual EGFR/HER2 tyrosine kinase inhibitor, GW572016, on EGFR/HER2 receptor phosphorylation, inhibition of downstream signaling and radiosensitization in either an EGFR or HER2 overexpressing human breast cancer xenograft. MATERIALS AND METHODS: We established SCID mice xenografts from 4 human breast cancer cell line that overexpressed EGFR or HER 2 (SUM 102, SUM 149, SUM 185, SUM 225). Two series of xenografts were established. One series was established for determining inhibition of the EGFR/HER2 receptor and downstream signaling activities by GW572016. The other series was established for determining the radiosensitization effect of GW572016. Inhibition of the receptor and downstream signaling proteins were measured by the use of immunoprecipitation and Western blotting. For determining the in vivo radiosensitization effect of GW572016, we compared tumor growth delay curves in the following four treatment arms: a) control; b) GW572016 alone; c) radiotherapy (RT) alone; d) GW572016 and RT. RESULTS: GW572016 inhibited EGFR, HER2 receptor phosphorylation in SUM 149 and SUM 185 xenografts. In addition, the p44/42 MAPK (ERK 1/2) downstream signaling pathway was inactivated by GW572016 in the SUM 185 xenograft. In the SUM 225 xenograft, we could not observe inhibition of HER2 receptor phosphorylation by GW572016; both p44/42 MAPK (Erk1/2) and Akt downstream signal protein phosphorylation were inhibited by GW572016. GW572016 inhibited growth of the tumor xenograft of SUM 149 and SUM 185. The combination of GW572016 and RT enhanced growth inhibition greater than that with GW572016 alone or with RT alone in the SUM 149 xenograft. GW572016 appears to act as an in vivo radiosensitizer. CONCLUSION: GW572016 inhibited EGFR/HER2 receptor phosphorylation and downstream signaling pathway proteins. GW572016 modestly inhibited the growth of tumor in the SUM 185 xenograft and showed radiosensitization in the SUM 149 xenograft. Our results suggest that a better predictor of radiation response would be inhibition of a crucial signaling pathway than inhibition of a receptor.

The Development of Quality Assurance Program for CyberKnife / 대한방사선종양학회지

PURPOSE: Standardization quality assurance (QA) program of CyberKnife for suitable circumstances in Korea has not been established. In this research, we investigated the development of QA program for CyberKnife and evaluation of the feasibility under applications. MATERIALS AND METHODS: Considering the feature of constitution for systems and the therapeutic methodology of CyberKnife, the list of quality control (QC) was established and divided dependent on the each period of operations. And then all these developed QC lists were categorized into three groups such as basic QC, delivery specific QC, and patient specific QC based on the each purpose of QA. In order to verify the validity of the established QA program, this QC lists was applied to two CyberKnife centers. The acceptable tolerance was based on the undertaking inspection list from the CyberKnife manufacturer and the QC results during last three years of two CyberKnife centers in Korea. The acquired measurement results were evaluated for the analysis of the current QA status and the verification of the propriety for the developed QA program. RESULTS: The current QA status of two CyberKnife centers was evaluated from the accuracy of all measurements in relation with application of the established QA program. Each measurement result was verified having a good agreement within the acceptable tolerance limit of the developed QA program. CONCLUSION: It is considered that the developed QA program in this research could be established the standardization of QC methods for CyberKnife and confirmed the accuracy and stability for the image-guided stereotactic radiotherapy.

The Effect of Simulation on Recurrence after Breast-Conserving Surgery and Radiotherapy : Preliminary Results / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: To evaluate the effect of the simulation method on recurrence among the patients who received radiotherapy after breast-conserving surgery (BCS) for early breast carcinoma. METHODS AND MATERIALS: Between 1995 and 2000, 70 patients with stage I-II breast carcinoma underwent breast-conserving surgery and adjuvant radiotherapy. Twenty nine patients (41.4%) were simulated with the 2D contour-based method (September 1995 to August 1997) and 41 patients (58.6%) were simulated with the 3D CT-based method (September 1997 to February 2000). To analyze the effect of the simulation method, the patient and treatment characteristics were compared. RESULTS: The characteristics were similar for the patients between the 2D contour-based simulation group and the 3D CT-based simulation group. During a median follow-up period of 75 months, 4 (13.8%) of 29 patients who were treated with 2D simulation and 1 (2.4%) of 41 patients who were treated with 3D simulation group devel-oped treatment failure. The five-year survival rates were 89.2% and 95.1% between the 2D and 3D simulation groups (p=0.196). The five-year disease free survival (DFS) rates were 86.2% and 97.5% between the 2D and 3D simulation groups (p=0.0636). On univariate analysis, age > 40 (p= 0.0226) and the number of dissected axillary lymph node > or = 10 (p=0.0435) were independent predictors of improved 5-year DFS. CONCLUSIONS: Although our data showed marginal significance for the DFS between the two groups, it is insufficient, due to the small number of patients in our study, to prove whether 3D CT-based simulation might improve the DFS and reduce the risk of recurrence when compared with 2D contour-based simulation. Further study is needed with a larger group of patients.

The Results of Palliative Radiation Therapy in Patients with Unresectable Advanced Pancreatic Cancer / 대한방사선종양학회지

PURPOSE: To evaluate the treatment results and prognostic factors of palliative radiation therapy in the patients with unresectable advanced pancreatic cancer. MATERIALS AND METHODS: Thirty-seven evaluable patients with unresectable advanced pancreatic cancer who were treated by palliative radiation therapy for pain relief at the Department of Radiation Oncology, Kangnam St. Mary's hospital, the Catholic University of Korea between March 1984 and February 2005 were analysed retrospectively. There were 22 men and 15 women. Age at diagnosis ranged from 30 to 80 (median 57) years. Twelve patients (32.4%) had liver metastases and 22 patients (59.5%) had lymph node metastases. Radiation therapy was delivered to primary tumor and regional lymph nodes with 1~2 cm margin, and total dose was 3,240~5,580 cGy (median 5,040 cGy). Chemotherapy with radiotherapy was delivered in 30 patients (81%) with 5-FU alone (21 patients) or gemcitabine (9 patients). The follow-up period ranged from 1 to 44 months. Survival and prognostic factors were analysed using Kaplan-Meier method and log-rank test respectively. RESULTS: Overall mean and median survival were 11 and 8 months and 1-year survival rate was 20%. Among 33 patients who were amenable for response evaluation, 7 patients had good response and 22 patients had fair response with overall response rate of 87.9%. Mild to moderate toxicity were observed in 14 patients with nausea, vomiting, and indigestion, but severe toxicity requiring interruption of treatment were not observed. Chemotherapy didn't influence the survival and symptomatic palliation, but the group containing gemcitabine showed a tendency of longer survival (median 12 months) than 5-FU alone group (median 5.5 months) without statistical significance (p>0.05). The significant prognostic factors were Karnofsky performance status and liver metastasis (p0.05). CONCLUSION: Radiation therapy was effective for symptomatic palliation in the patients with unresectable advanced pancreatic cancer and would play an important part in the survival benefit with gemcitabine or other targeted agents.

Effects of Ionizing Radiation and Cisplatin on Peroxiredoxin I & II Expression and Survival Rate in Human Neuroblastoma and Rat Fibroblast Cells / 대한방사선종양학회지

PURPOSE: This study investigated the influence of irradiation and cisplatin on PrxI & PrxII expression and on their survival rates (SR) in SK-N-BE2C and Rat2 cell lines. MATERIALS AND METHODS: The amount of PrxI & PrxII production with or without N-acetyl-L-cysteine (NAC) pretreatment was studied using a western blot after 20 Gy irradiation to determine the degree of inhibition of ROS accumulation. In addition, the amount of PrxI & PrxII production after cisplatin and after combination with cisplatin and 20 Gy irradiation was studied. The SRs of the cell lines in SK-N-BE2C and Rat 2 cells, applied with 20 Gy irradiation only, with various concentrations of cisplatin and with the combination of both, were studied. The 20 Gy irradiation-only group and the combination group were each subdivided according to NAC pretreatment, and corresponding SRs were observed at 2, 6, 12 and 48 hours after treatment. RESULTS: Compared with the control group, the amount of PrxI in SK-N-BE2C increased up to 60 minutes after irradiation and slightly increased after irradiation with NAC pretreatment 60 minutes. It did not increase in Rat2 after irradiation regardless of NAC pretreatment. PrxII in SK-N-BE2C and Rat2 was not increased after irradiation regardless of NAC pretreatment. The amounts of PrxI and PrxII in SK-N-BE2C and Rat2 were not increased either with the cisplatin-only treatment or the combination treatment with cisplatin and irradiation. SRs of irradiation group with or without NAC pretreatment and the combination group with or without NAC pretreatment were compared with each other in SK-N-BE2C and Rat2. SR was significantly high for the group with increased amount of PrxI, NAC pretreatment and lower the cisplatin concentration. SR of the group in SK-N-BE2C which had irradiation with NAC pretreatment tended to be slightly higher than the group who had irradiation without NAC pretreatment. SR of the group in Rat2 which had irradiation with NAC pretreatment was significantly higher than that the group which had irradiation without NAC pretreatment. Compared to the combination group, the irradiation-only group revealed statistically significant SR decrease with the maximal difference at 12 hours. However, at 48 hours the SR of the combination group was significantly lower than the irradiation-only group. CONCLUSION: PrxI is suggested to be an antioxidant enzyme because the amount of PrxI was increased by irradiation but decreased pretreatment NAC, a known antioxidants. Furthermore, cisplatin may inhibit PrxI production which may lead to increase cytotoxicity of irradiation. The expression of PrxI may play an important role in cytotoxicity mechanism caused by irradiation and cisplatin.