It is well known that intracavitary radiotherapy (ICR), either alone or in combination with external-beam radiotherapy (EBRT) is an essential component of the radiation treatment of uterine cervical cancer. Although low-dose-rate (LDR) brachytherapy has been successfully applied to the management of such patients, several radiation oncologists have experience of using high-dose-rate (HDR) brachytherapy with promising clinical results over the past 4 decades. However, there has been a considerable reluctance by radiation oncologists and gynecologists in North America to employ the HDR remote afterloading technique instead of the more firmly established LDR treatment modality. In contrast, the HDR-ICR system is rapidly gaining acceptance in Korea since the introduction of the Ralstron, remotely controlled afterloading system using HDR Co-60 sources, at the Yonsei Cancer Center in 1979. According to brachytherapy statistics reported by the Korean Society of Therapeutic Radiology and Oncology, in 1997, brachytherapy was performed upon 1,758 Korean patients with uterine cervical cancer, of whom approximately 83% received HDR brachytherapy. In this review, we present our experiences of HDR-ICR for the treatment of uterine cervical cancer. In addition, we discuss the controversial points, which are raised by those considering the use of HDR-ICR for uterine cervical cancer; these issues include physical and radiobiological considerations, and the prospect of future technical improvements.
Brachytherapy/*methods ; Cervix Neoplasms/*radiotherapy ; Dose Fractionation ; Female ; Human ; Radiotherapy Planning, Computer-Assisted

To access the result of radiation therapy for 8 years experiences, 21 patients who were treated with superior vena cava syndrome had been analysed according to dose fractionation and toal dose. The results are as follows; 1. In high fractionate dose group, six of eleven patients (54.5%) exhibited relief of symptoms in 1-2 days, and additional three patients of nine (81.7%) within 3-4 days, while standard fractionated dose treatment is not effective to achieve initial relief of symptoms. 2. Graded response by total dose was correlated with total dose rather than dose fractionation. 3. Overall one year survival rate with superior vana cava syndrome was 9.1% and mean survival was 4.2 months.
Dose Fractionation ; Humans ; Radiotherapy ; Superior Vena Cava Syndrome* ; Survival Rate ; Vena Cava, Superior*

The schemes of dose fractionation play an important role in tumor radiotherapy. We used mathematical methods to describe the process of tumor cells evolution during radiotherapy, trying to find how the schemes of dose fractionation affect tumor cells. In clinical radiobiology, linear-quadratic (LQ) model is frequently used to describe radiation effects of tumor cells. We integrated LQ model with effect of oxygen, and with the phenomenon of repopulation and reoxygenation in the theory of radiation biology. While we considered the disappearing progress of doomed cells in tumor, we established the mathematical model of tumor evolution in radiotherapy. We simulated some common treatment schedules, and studied the change role of tumor cells during radiotherapy. These results can serve for the optimization of dose fractionation scheme based on tumor radiobiological characteristics.
Cell Growth Processes ; radiation effects ; Dose Fractionation ; Humans ; Models, Theoretical ; Neoplasms ; pathology ; physiopathology ; radiotherapy ; Radiobiology

Total of 53 patients of unresectable and recurrent rectal cancer treated with neutron beam during the period from Oct. 1987 to Apr. 1992 were analyzed. Dose fractionation for the neutron only group was 1.5 Gy per fraction, 3 fraction per week, 21 Gy/41/2 wks for 42 patients out of 53(76%). Neutron only but modified fractionation schedule (10% more or less of total dose) was applied for 9 patients, and mixed team (neutron boost) was for 4 patients. Complete tumor response was obtained in 40 patients(76% response rate). Local control rate was 28 out of 53(53%). Statistically significant better prognostic factors for local control were age below 49 years old (15/22, 68%) than above 50 years old (13/31, 42%), male (20/32, 63%) than female(8/21, 38%), tumor size less than 5 cm and non-metastatic(16/24, 67%) than size more than 5 cm or metastatic(12/29, 4l%). Major complication had developed in 7 patients (13%). Two year overall survival rate by Kaplan-Meier method was 30%, but it was rised to, 47% when the tumor was less than 5cm non-metastatic.
Appointments and Schedules ; Dose Fractionation ; Humans ; Male ; Middle Aged ; Neutrons* ; Rectal Neoplasms* ; Survival Rate

PURPOSE: The purpose of this study was to describe treatment patterns of radiotherapy (RT) for prostate cancer in Korea. MATERIALS AND METHODS: A questionnaire about radiation treatment technique and principles in 2013 was sent to 83 radiation oncologists and data from 57 hospitals were collected analyzed to find patterns of RT for prostate cancer patients in Korea. RESULTS: The number of patients with prostate cancer treated with definitive RT ranged from 1 to 72 per hospital in 2013. RT doses and target volumes increased according to risk groups but the range of radiation doses was wide (60 to 81.4 Gy) and the fraction size was diverse (1.8 to 5 Gy). Intensity-modulated radiation therapy was used for definitive treatment in 93.8% of hospitals. Hormonal therapy was integrated with radiation for intermediate (63.2%) and high risk patients (77.2%). Adjuvant RT after radical prostatectomy was performed in 46 hospitals (80.7%). Indications of adjuvant RT included positive resection margin, seminal vesicle invasion, and capsular invasion. The total dose for adjuvant RT ranged from 50 to 72 Gy in 24–39 fractions. Salvage RT was delivered with findings of consecutive elevations in prostate-specific antigen (PSA), PSA level over 0.2 ng/mL, or clinical recurrence. The total radiation doses ranged from 50 to 80 Gy with a range of 1.8 to 2.5 Gy per fraction for salvage RT. CONCLUSION: This nationwide patterns of care study suggests that variable radiation techniques and a diverse range of dose fractionation schemes are applied for prostate cancer treatment in Korea. Standard guidelines for RT in prostate cancer need to be developed.
Dose Fractionation ; Humans ; Korea* ; Prostate* ; Prostate-Specific Antigen ; Prostatectomy ; Prostatic Neoplasms* ; Radiotherapy* ; Recurrence ; Seminal Vesicles

BACKGROUND/AIMS: This study reports treatment outcomes after helical intensity-modulated radiotherapy (IMRT) in unresectable hepatocellular carcinoma (HCC) patients for whom transarterial chemoembolization (TACE) was considered ineffective or unsuitable. METHODS: From January 2008 to December 2011, 22 unresectable HCC patients received helical IMRT. A daily dose of 1.8 to 4 Gy was delivered at five fractions per week to deliver a total dose of 30 to 60 Gy. The most-prescribed dose fractionation was a total dose of 50 to 57.5 Gy, with a daily dose of 2.3 to 2.5 Gy. RESULTS: In the entire group, the objective response rate of the primary tumor was 72.7%. In the eight patients with portal vein thrombosis (PVT), the objective response rate of PVT was 50.0%. Median disease progression-free survival was 11.8 months, and the 1-year disease progression-free survival rate was 40.2%. The median overall survival was 14.4 months, and the 1- and 2-year overall survival rates were 86.4% and 69.1%, respectively. PVT and Child-Pugh classifications were significant prognostic factors for overall survival in multivariate analyses. CONCLUSIONS: Helical IMRT in patients with unresectable HCC resulted in high treatment response and survival rates. This study suggests helical IMRT is a practical treatment option for HCC patients in whom TACE is unsuitable or ineffective.
Carcinoma, Hepatocellular ; Disease-Free Survival ; Dose Fractionation ; Humans ; Portal Vein ; Radiotherapy, Intensity-Modulated ; Survival Rate ; Thrombosis

PURPOSE: This study was conducted to compare clinical outcomes and treatment-related toxicities after stereotactic body radiation therapy (SBRT) with two different dose regimens for small hepatocellular carcinomas (HCC) ≤3 cm in size. MATERIALS AND METHODS: We retrospectively reviewed 44 patients with liver-confined HCC treated between 2009 and 2014 with SBRT. Total doses of 45 Gy (n = 10) or 60 Gy (n = 34) in 3 fractions were prescribed to the 95% isodose line covering 95% of the planning target volume. Rates of local control (LC), intrahepatic failure-free survival (IHFFS), distant metastasis-free survival (DMFS), and overall survival (OS) were calculated using the Kaplan-Meier method. RESULTS: Median follow-up was 29 months (range, 8 to 64 months). Rates at 1 and 3 years were 97.7% and 95.0% for LC, 97.7% and 80.7% for OS, 76% and 40.5% for IHFFS, and 87.3% and 79.5% for DMFS. Five patients (11.4%) experienced degradation of albumin-bilirubin grade, 2 (4.5%) degradation of Child-Pugh score, and 4 (9.1%) grade 3 or greater laboratory abnormalities within 3 months after SBRT. No significant difference was seen in any oncological outcomes or treatment-related toxicities between the two dose regimens. CONCLUSIONS: SBRT was highly effective for local control without severe toxicities in patients with HCC smaller than 3 cm. The regimen of a total dose of 45 Gy in 3 fractions was comparable to 60 Gy in efficacy and safety of SBRT for small HCC.
Carcinoma, Hepatocellular ; Dose Fractionation ; Follow-Up Studies ; Humans ; Methods ; Radiosurgery ; Retrospective Studies

OBJECTIVETo analyse the result of late course accelerated hyper-fractionated radiotherapy (LCAHFR) of upper and middle thoracic segment esophageal T2N0M0 carcinoma.

METHODSFifty-three patients with squamous cell esophageal T2N0M0 carcinoma in the upper and middle segment were treated by LCAHFR from August 1994 to January 2000. The design of the radiation fields were based on CT and barium examination. All patients were treated with the conventional fractionated radiotherapy during the first two-thirds of the treatment to a dose about 41.4 Gy/23 F/4 to 5 weeks. This was followed by accelerated hyper-fractionated irradiation using reduced fields, twice daily at 1.5 Gy per fraction to a dose about 27 Gy/18 d. Thus, the total dose was 67-70 Gy/40-43 F/40-49 d.

RESULTSThe 1-, 2- and 5-year actuarial survival rates were 89.9%, 66.8% and 51.2%, respectively. The 1-, 2- and 5-year local control rates were 92.1%, 87.1% and 87.1%. Of the 17 patients who died, 5 died of local failure (29.4%), 9 (52.9%) of distant metastasis, 5 (29.4%) of lymph metastasis and 1 (5.9%) of bleeding from the esophagus. The Cox multivariate model showed that the site of lesion was the only prognostic factor, with upper better than the middle segment.

CONCLUSIONLate course accelerated hyper fractionated radiotherapy is one of the best radiation treatment regimen for early esophageal carcinoma in the upper and middle thoracic segment.

Aged ; Carcinoma, Squamous Cell ; radiotherapy ; Dose Fractionation ; Esophageal Neoplasms ; radiotherapy ; Female ; Humans ; Male ; Middle Aged ; Treatment Outcome

PURPOSE: To analyze the radioresponse of hepatocellular carcinomas (HCC), using accurate measurements of the tumor size in extrahepatic lymph node metastasis, and to obtain information for the future treatment of primary intrahepatic lesions. MATERIALS AND METHODS: Fifty-one extrahepatic lymph node metastases from primary HCCs, which could be treated by external radiotherapy alone, were included in this study. The radiation dose ranged from 30 to 51 Gy with fraction sizes of 2.0~3.0 Gy. Responses were determined by measuring the areas on CT scans 0, 1 and 3 months after the completion of radiotherapy. The median follow-up period of the surviving patients was 10 months. RESULTS: The overall response rate was 76%, and the important factors were; total dose of radiation, time dose fractionation (TDF) value and the biologically effective dose (BED). A dose of 45 Gy or higher showed an objective response rate of 93%, and if the TDF value was higher than 90, a similar result was observed. In about half (47%) of the patients the maximum response was observed at 3 months or later. The response duration was observable in 14 patients surviving 12 months or longer. Regrowth of irradiated lesions were observed in 4 (66.7%) patients among those who received less than 45 Gy, and in 4 (50%) among those who were treated with 45 Gy or more. There was a statistically significant difference in the survivals between the responders and non-responders (p=0.008). Gastrointestinal bleeding or ulceration was observed in 8 patients, including 3 with NCI common toxicity criteria grade III or higher. CONCLUSION: Radiotherapy was an effective palliative modality for extrahepatic metastasis in HCCs. A radiation dose of 45 Gy or higher (or a TDF value > or =90), was required for a major response.
Carcinoma, Hepatocellular ; Dose Fractionation ; Follow-Up Studies ; Hemorrhage ; Humans ; Lymph Nodes* ; Neoplasm Metastasis* ; Radiotherapy ; Tomography, X-Ray Computed ; Ulcer

To evaluate the efficacy of hyperfractionated re-irradiation using a three-dimensional conformal radiotherapy (3-D CRT) technique in patients with locally recurrent carcinoma of the nasopharynx. Four patients with locally recurrent nasopharyngeal cancer were retreated with a hyperfractionated schedule using a 3-D CRT technique. Re-irradiation was delivered in 1.1-1.2 Gy fractions twice per day (BID), with interfraction intervals of more than 6 hours. The total dose ranged from 59.4 to 69.2 Gy. A 3-D CRT technique with 5- or 6-field coplanar and/or non-coplanar beams were employed during the entire treatment procedure. All four patients achieved complete remission of locally recurrent lesions, with marked improvement of subjective symptoms, immediately after re-irradiation. All are alive and well without evidence of disease after limited follow-up periods, which range from 7 to 20 months. So far, there have been no radiation-induced neurologic complications. Four patients with locally recurrent carcinoma of the nasopharynx were successfully treated by hyperfractionated re-irradiation using a 3-D CRT technique. A relatively high re-irradiation dose of more than 60 Gy may be safely delivered with no serious acute or late radiation-induced complications in patients with local recurrences and who were initially treated with doses greater than 70 Gy.
Aged ; Dose Fractionation* ; Human ; Male ; Middle Age ; Nasopharyngeal Neoplasms/radiotherapy* ; Neoplasm Recurrence, Local/radiotherapy* ; Radiotherapy Dosage ; Radiotherapy, Conformal*