• Asian Pacific Journal of Cancer Prevention
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• 제15권6호
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• pp.2793-2796
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• 2014

Background: Glioblastoma multiform (GBM) is a highly aggressive tumor with median survival of approximately 14 months. Management consists of maximal surgical resection followed by post-operative chemoradiation with concurrent then adjuvant temozolamide. The standard radiotherapy dose is 60Gy in 2-Gy fractions recommended by the radiation therapy oncology group (RTOG). With the vast majority of tumor recurrences occurring within the previous irradiation field and the poor outcome associated with standard therapy, regimens designed to deliver higher radiation doses to improve local control and enhance survival are needed. In this study, we report a single institutional experience in treatment of 68 consecutive patients with GBM, treated with resection, and given post-operative radiotherapy followed by concurrent and/or adjuvant chemotherapy. Results: Of the 80 patients who entered this study, 68 completed the treatment course; 45 (66.2%) males and 23 (33.8%) females with a mean age at diagnosis of $49.0{\pm}12.9$ (21-75) years. At a median follow up of 19 months, 39 (57.3%) patients had evidence of tumor progression and 36 (52.9%) had died. The median over all survival for all patients was 16 months and progression free survival for all patients was 6.02 months. All potential prognostic factors were analyzed to evaluate their effects on overall survival. Age ${\leq}50$ year, concurrent and adjuvant chemotherapy and extent of surgery had significant p values. We found lower progression rate among patients who received higher doses of radiotherapy (>60Gy). Higher radiation doses improved progression free survival (p=0.03). Despite increasing overall survival, this elevation was not significant. Conclusions: This study emphasize that higher radiation doses of (>60Gy) can improve local control and potentially survival, so we strongly advise prospective multi centric studies to evaluate the role of higher doses of radiotherapy on GBM patient outcome.

• Asian Pacific Journal of Cancer Prevention
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• 제16권7호
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• pp.2889-2894
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• 2015

Background: To investigate the impact of the breast size, shape, maximum heart depth (MDH), and chest wall hypotenuse (the distance connecting middle point of the sternum and the length of lung draw on the selected transverse CT slice) on the volumetric dose to heart with whole breast irradiation (WBI) of left-sided breast cancer patients. Materials and Methods: Fifty-three patients with left-sided breast cancer undergoing adjuvant intensity-modulated radiotherapy (IMRT) were enrolled in the study. The primary breast size and shape, MHD and DCWH (chest wall hypotenuse) were contoured on radiotherapy (RT) planning CT slices. The dose data of hearts were obtained from the dose-volume histograms (DVHs). Data were analyzed by one-way analysis of variance (ANOVA), Student's t-test and linear regression analysis. Results: Breast size was independent of heart dose, whereas breast shape, MHD and DCWH were correlated with heart dose. The shapes of breasts were divided into four types, as the flap type, hemisphere type, cone type and pendulous type with heart mean dose being $491.8{\pm}234.6cGy$, $752.7{\pm}219.0cGy$, $620.2{\pm}275.7cGy$, and $666.1{\pm}238.0cGy$, respectively. The flap type of breasts shows a strong statistically reduction in heart dose, compared to others (p=0.008 for V30 of heart). DCWH and MHD were found to be the most important parameters correlating with heart dose in WBI. Conclusions: More attention should be paid to the heart dose of non-flap type patients. The MHD was found to be the most important parameter to correlate with heart dose in tangential WBI, closely followed by the DCWH, which could help radiation oncologists and physicsts evaluate heart dose and design RT plan in advance.

• Radiation Oncology Journal
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• 제34권4호
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• pp.265-272
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• 2016

Purpose: The purpose of this study is to evaluate the treatment outcomes of adjuvant radiotherapy using vaginal brachytherapy (VB) with a lower dose per fraction and/or external beam radiotherapy (EBRT) following surgery for patients with stage I endometrial carcinoma. Materials and Methods: The subjects were 43 patients with the International Federation of Gynecology and Obstetrics (FIGO) stage I endometrial cancer who underwent adjuvant radiotherapy following surgery between March 2000 and April 2014. Of these, 25 received postoperative VB alone, while 18 received postoperative EBRT to the whole pelvis; 3 of these were treated with EBRT plus VB. The median EBRT dose was 50.0 Gy (45.0-50.4 Gy) and the VB dose was 24 Gy in 6 fractions. Tumor dose was prescribed at a depth of 5 mm from the cylinder surface and delivered twice per week. Results: The median follow-up period for all patients was 57 months (range, 9 to 188 months). Five-year disease-free survival (DFS) and overall survival (OS) for all patients were 92.5% and 95.3%, respectively. Adjuvant radiotherapy was performed according to risk factors and stage IB, grade 3 and lymphovascular invasion were observed more frequently in the EBRT group. Five-year DFS for EBRT and VB alone were 88.1% and 96.0%, respectively (p = 0.42), and 5-year OS for EBRT and VB alone were 94.4% and 96%, respectively (p = 0.38). There was no locoregional recurrence in any patient. Two patients who received EBRT and 1 patient who received VB alone developed distant metastatic disease. Two patients who received EBRT had severe complications, one each of grade 3 gastrointestinal complication and pelvic bone insufficiency fracture. Conclusion: Adjuvant radiotherapy achieved high DFS and OS with acceptable toxicity in stage I endometrial cancer. VB (with a lower dose per fraction) may be a viable option for selected patients with early-stage endometrial cancer following surgery.

• Asian Pacific Journal of Cancer Prevention
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• 제16권8호
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• pp.3257-3265
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• 2015

Background: Radiotherapy is an important treatment of choice for breast cancer patients after breast-conserving surgery, and we compare the feasibility of using dual arc volumetric modulated arc therapy (VMAT2), single arc volumetric modulated arc therapy (VMAT1) and Multi-beam Intensity Modulated Radiotherapy (M-IMRT) on patients after breast-conserving surgery. Materials and Methods: Thirty patients with breast cancer (half right-sided and half left-sided) treated by conservative lumpectomy and requiring whole breast radiotherapy with tumor bed boost were planned with three different radiotherapy techniques: 1) VMAT1; 2) VMAT2; 3) M-IMRT. The distributions for the planning target volume (PTV) and organs at risk (OARs) were compared. Dosimetries for all the techniques were compared. Results: All three techniques satisfied the dose constraint well. VMAT2 showed no obvious difference in the homogeneity index (HI) and conformity index (CI) of the PTV with respect to M-IMRT and VMAT1. VMAT2 clearly improved the treatment efficiency and can also decrease the mean dose and V5Gy of the contralateral lung. The mean dose and maximum dose of the spinal cord and contralateral breast were lower for VMAT2 than the other two techniques. The very low dose distribution (V1Gy) of the contralateral breast also showed great reduction in VMAT2 compared with the other two techniques. For the ipsilateral lung of right-sided breast cancer, the mean dose was decreased significantly in VMAT2 compared with VMAT1 and M-IMRT. The V20Gy and V30Gy of the ipsilateral lung of the left-sided breast cancer for VMAT2 showed obvious reduction compared with the other two techniques. The heart statistics of VMAT2 also decreased considerably compared to VMAT1 and M-IMRT. Conclusions: Compared to the other two techniques, the dual arc volumetric modulated arc therapy technique reduced radiation dose exposure to the organs at risk and maintained a reasonable target dose distribution.

• Radiation Oncology Journal
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• 제13권2호
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• pp.173-180
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• 1995

Purpose: Unresectable rectal cancer has a grave prognosis. regardless of the therapy used and median survival is less than 1 rear. Also, it is reported by many authors that $50-80\%$ of unresectable lesions were rendered resectable by radiation therapy and the median survival time for the completely resected patients were better than that of the unresected patients. So we analyzed retrospectively our data for the better treatment outcome in these patients. Materials and MEthods:From 1980 to 1992, 45 patients with initially unresectable tumors in the rectum were treated with radiation therapy with/without surgery in Department of Radiation Oncology, Yonsei Cancer Center 10 MV radiation and multiple field technique (box or AP/PA) were used. The total dose was 28-70 Gy and median dose was 48 Gy. We evaluated the lesion status at 45-50 Gy for operability. If the lesions appeared to be resectable, the Patients were operated on 4-6 weeks after radiation therapy. But if the lesions were still fixed, the radiation dose was increased to 60-65 Gy. Results: For all patients, the 2-year actuarial survival was $13.3\%$ and median survival was 9.5 months. Of 6 patients who had received less than 45 Gy, only $17\%$ of patients responded, but in the patients who had received more than 45 Gy, $60\%$ of response rate was achieved Six of the 24 patients$(25\%)$ underwent surgical resections following RT. For patients undergoing curative resection. the two-rear survival was $50\%,$ but that of the patients without resection was $9.5\%$ (p<0.01). Survival of patients with complete response following RT was $50\%$ at 2 years. Survival of patients with partial response, stable disease and progressive disease after RT was $13.4\%,\;15.4\%,\;0\%$ respectively (P<0.05). Conclision: Our data suffests that the efforts which can increase the response rate and aggressive surgical approach are needed to achieve the better local control and survival in unresectable rectal cancers.

• Radiation Oncology Journal
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• 제29권4호
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• pp.236-242
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• 2011

Purpose: To compare photon thunderbird with deep match (technique 1) with 3-field technique with electron inguinal boost (technique 2) in acute skin toxicity, toxicity-related treatment breaks and patterns of failure in elective inguinal radiation therapy (RT) for curative chemoradiation in anal cancer. Materials and Methods: Seventeen patients treated between January 2008 and September 2010 without evidence of inguinal and distant metastasis were retrospectively reviewed. In 9 patients with technique 1, dose to inguinal and whole pelvis area was 41.4 to 45 Gy and total dose was 59.4 Gy. In 8 patients with technique 2, doses to inguinal, whole pelvis, gross tumor were 36 to 41.4 Gy, 36 to 41.4 Gy, and 45 to 54 Gy, respectively. The median follow-up period was 27.6 and 14.8 months in group technique 1 and 2, respectively. Results: The incidences of grade 3 radiation dermatitis were 56% (5 patients) and 50% (4 patients), dose ranges grade 3 dermatitis appeared were 41.4 to 50.4 Gy and 45 to 54 Gy in group technique 1 and 2, respectively (p = 0.819). The areas affected by grade 3 dermatitis in 2 groups were as follow: perianal and perineal areas in 40% and 25%, perianal and inguinal areas in 0% and 50%, and perianal area only in 60% and 25%, respectively (p = 0.196). No inguinal failure has been observed. Conclusion: Photon thunderbird with deep match technique and 3-field technique with electron inguinal boost showed similar incidence of radiation dermatitis. However, photon thunderbird with deep match seems to increase the possibility of severe perineal dermatitis.

• Journal of Korean Neurosurgical Society
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• 제45권5호
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• pp.275-283
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• 2009

Objective : We retrospectively analyzed survival, local control rate, and incidence of radiation toxicities after radiosurgery for recurrent metastatic brain lesions whose initial metastases were treated with whole-brain radiotherapy. Various radiotherapeutical indices were examined to suggest predictors of radiation-related neurological dysfunction. Methods : In 46 patients, total 100 of recurrent metastases (mean 2.2, ranged 1-10) were treated by CyberKnife radiosurgery at average dose of 23.1 Gy in 1 to 3 fractions. The median prior radiation dose was 32.7 Gy, the median time since radiation was 5.0 months, and the mean tumor volume was $12.4cm^3$. Side effects were expressed in terms of radiation therapy oncology group (RTOG) neurotoxicity criteria. Results : Mass reduction was observed in 30 patients (65%) on MRI. After the salvage treatment, one-year progression-free survival rate was 57% and median survival was 10 months. Age(<60 years) and tumor volume affected survival rate(p=0.03, each). Acute (${\leq}$1 month) toxicity was observed in 22% of patients, subacute and chronic (>6 months) toxicity occurred in 21 %, respectively. Less acute toxicity was observed with small tumors (<$10cm^3$. p=0.03), and less chronic toxicity occurred at lower cumulative doses (<100 Gy, p=0.004). "Radiation toxicity factor" (cumulative dose times tumor volume of <1,000 Gy${\times}cm^3$) was a significant predictor of both acute and chronic CNS toxicities. Conclusion: Salvage CyberKnife radiosurgery is effective for recurrent brain metastases in previously irradiated patients, but careful evaluation is advised in patients with large tumors and high cumulative radiation doses to avoid toxicity.

• Radiation Oncology Journal
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• 제36권2호
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• pp.153-162
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• 2018

Purpose: We aimed to evaluate clinical outcomes including progression-free survival (PFS), overall survival (OS), partial response, and complete response in patients who underwent radiation therapy (RT) for mycosis fungoides (MF). Also, we sought to find prognostic factors for clinical outcomes. Materials and Methods: Total 19 patients confirmed with MF between 1999-2015 were retrospectively reviewed. Clinical and treatment characteristics, clinical outcomes, and and toxicities were analyzed. Results: Eleven patients were treated with total skin electron beam radiotherapy (TSEBT) and 8 patients with involved field radiation therapy (IFRT) with median dose of 30 Gy, respectively. The median time interval from diagnosis to RT was 2.6 months (range, 0.4 to 87.3 months). The overall response rate was 100%; 11 patients (57.9%) had a complete response and 8 patients (42.1%) a partial response. The presence of positive lymph node at the time of consultation of RT was associated with lower OS (p = 0.043). In multivariate analysis, PFS was significantly lower for patients with increased previous therapies experienced following RT (p = 0.019) and for patients showing PR during RT (p = 0.044). There were no reported grade 3 or more skin toxicities related with RT. Conclusion: Both IFRT and TSEBT are effective treatment for MF patients. Patients with short disease course before RT or complete response during RT are expected to have longer PFS. Positive lymph node status at the initiation of RT was associated woth poor OS, suggesting other treatment modalities such as low-dose RT for patients with low life-expectancy.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.123-131
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• 2024

Electron paramagnetic resonance (EPR) dosimetry for a tooth from an individual exposed is well known as retrospective dosimetry in radiological accidents. A major constraint of the conventional X-band tooth-EPR dosimetry is the necessity to extract the tooth of the exposed patient for dose assessment. In this study, to conduct the dose assessments of exposed patients through part-extraction of tooth enamel, the minimum detectable dose (MDD) of the tooth enamel was evaluated based on the amount of mass. Further, a field test was conducted via intercomparison using various dose assessment methods to verify the feasibility of X-band tooth-EPR dosimetry using the minimum mass of tooth enamel. The intercomparison results demonstrated that effective dose determination via X-band tooth-EPR dosimetry is reliable. Consequently, it was determined that the minimum mass of tooth enamel required to evaluate an absorbed dose above 0.5 Gy is 15 mg. Thus, EPR dosimetry using 15 mg of tooth enamel can be applied in the triage and initial medical response stages for patients exposed during radiological accidents. This approach represents an advancement in managing radiological accidents by offering a more efficient and less invasive method of dose assessment.

• Radiation Oncology Journal
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• 제2권2호
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• pp.177-184
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• 1984

A retrospective analysis of survival data of i2 cases with brain astrocytomas was presented. All patients received post·operative radiotherapy in the period of $1973\~1983$ at YUMC, Yonsei Cancer Center. There were 24 patients with Grade II, 12 patients with Grade III and 16 patients with Grade IV astrocytomas. Survival rates o ere analyzed according to histologic grade of malignancy, age, tumor location, radiation dose and extent of surgical tumor resection. 5year actuarial survival for patients with Grade II astrocytomas was $32.9\%$ and Grade III was $42.9\%$. The 1 year and 2 year survival rate of Grade astrocytomas were $46.7\%$ and $0\%$. Histologic grade of tumor was important prognostic factor in brain astrocytomas. Age and extent of surgical resection were significant prognostic (actors in all grades of astrocytomas and tumor location and radiation dose were significant in Grade f astrocytomas.