The 1998, 1999 Patterns of Care Study for Breast Irradiation after Mastectomy in Korea / 대한방사선종양학회지

PURPOSE: To determine the patterns of evaluation and treatment in patients with breast cancer after mastectomy and treated with radiotherapy. A nationwide study was performed with the goal of improving radiotherapy treatment. MATERIALS AND METHODS: A web-based database system for the Korean Patterns of Care Study (PCS) for 6 common cancers was developed. Randomly selected records of 286 eligible patients treated between 1998 and 1999 from 17 hospitals were reviewed. RESULTS: The ages of the study patients ranged from 20 to 80 years (median age 44 years). The pathologic T stage by the AJCC was T1 in 9.7% of the cases, T2 in 59.2% of the cases, T3 in 25.6% of the cases, and T4 in 5.3% of the cases. For analysis of nodal involvement, N0 was 7.3%, N1 was 14%, N2 was 38.8%, and N3 was 38.5% of the cases. The AJCC stage was stage I in 0.7% of the cases, stage IIa in 3.8% of the cases, stage IIb in 9.8% of the cases, stage IIIa in 43% of the cases, stage IIIb in 2.8% of the cases, and IIIc in 38.5% of the cases. There were various sequences of chemotherapy and radiotherapy after mastectomy. Mastectomy and chemotherapy followed by radiotherapy was the most commonly performed sequence in 47% of the cases. Mastectomy, chemotherapy, and radiotherapy followed by additional chemotherapy was performed in 35% of the cases, and neoadjuvant chemoradiotherapy was performed in 12.5% of the cases. The radiotherapy volume was chest wall only in 5.6% of the cases. The volume was chest wall and supraclavicular fossa (SCL) in 20.3% of the cases; chest wall, SCL and internal mammary lymph node (IMN) in 27.6% of the cases; chest wall, SCL and posterior axillary lymph node in 25.9% of the cases; chest wall, SCL, IMN, and posterior axillary lymph node in 19.9% of the cases. Two patients received IMN only. The method of chest wall irradiation was tangential field in 57.3% of the cases and electron beam in 42% of the cases. A bolus for the chest wall was used in 54.8% of the tangential field cases and 52.5% of the electron beam cases. The radiation dose to the chest wall was 45~59.4 Gy (median 50.4 Gy), to the SCL was 45~59.4 Gy (median 50.4 Gy), and to the PAB was 4.8~38.8 Gy, (median 9 Gy) CONCLUSION: Different and various treatment methods were used for radiotherapy of the breast cancer patients after mastectomy in each hospital. Most of treatment methods varied in the irradiation of the chest wall. A separate analysis for the details of radiotherapy planning also needs to be followed and the outcome of treatment is needed in order to evaluate the different processes.

Parotid Gland Sparing Radiotherapy Technique Using 3-D Conformal Radiotherapy for Nasopharyngeal Carcinoma / 대한방사선종양학회지

PURPOSE: Although using the high energy photon beam with conventional parallel-opposed beams radio-therapy for nasopharyngeal carcinoma, radiation-induced xerostomia is a troublesome problem for patient. We conducted this study to explore a new parotid gland sparing technique in 3-D conformal radiotherap (3-D CRT) in an effort to prevent the radiation-induced xerostomia. MATERIALS AND METHODS: We performed three different planning for four clinically node-negative naso-phar yngeal cancer patients with different location of tumor(intracranial extension, nasal cavity extension, oropharyngeal extension, parapharyngeal extension), and intercompared the plans. Total prescription dos <. Was 70.2 Gy to the isocenter, For plan-A, 2-D parallel opposing fields, a conventional radiotherapy technique, were employed. For plan-B, 2-D parallel opposing fields were used up until 54 Gy an < 3 afterwards 3-D non-coplanar beams were used. For plan-C, the new technique, 54 Gy was delivered b r 3-D conformal 3-port beams (AP and both lateral ports with wedge compensator; shielding both superficial lobes of parotid glands at the AP beam using BEV) from the beginning of the treatment and early spinal cord block (at 36 Gy) was performed. And bilateral posterio r necks were treated with electron after 36 Gy. After 54 Gy, non-coplanar beams were used for cone-down plan. We intercompared dose statistic; Dmax, Dmin, Dmean, D95, D05, V95, V05, Volume receiving 46 Gy) and dose volume histograms (DVH) of tumor and normal tissues and NTCP values of parotid glands for the above three plans. RESULTS: For all patients, the new technique (plan-C) was comparable or superior to the other plans in target volume isodose distribution and dose statistics and it has more homogenous target volume, coverage. The new technique was most superior to the other plans in parotid glands sparing (volume receiving 46 Gy: 100, 9 B, 69% for each plan-A, B and C). And it showed the lowest NTCP value of parotid glands in all patients (range of NTCP; 96-100%, 79-99%, 51-72% for each plan-A, B and C). CONCLUSION: We conclude that the new technique employing 3-D conformal radiotherapy at the beginning of radiotherapy and cone down using non-coplanar beams with early spinal cord block is highly recommended to spare parotid glands for node-negative nasopharygeal cancer patients.

Optimization of Dose Distribution for High Dose Rate Intraluminal Therapy / 대한치료방사선과학회지

The use of high dose rate remote afterloading system for the treatment of intraluminal lesions necessitates the need for a more accurate of dose distributions around the high intensity brachytherapy sources, doses are often prescribed to a distance of few centimeters from the linear source, and in this range the dose distribution is very difficult to assess. Accurated and optimized dose calculation with stable numerical algorithms by PC level computer was required to treatment intraluminal lesions by high dose rate brachytherapy system. The exposure rate from sources was calculated with Sievert integral and dose rate in tissue was calculated with Meisberger equation. An algorithm for generating a treatment plan with optimized dose distribution was developed for high dose rate intraluminal radiotherapy. The treatment volume becomes the locus of the constrained target surface points that is the specified radial distance from the source dwelling positions. The treatment target volume may be alternately outlined on a x-ray film of the implant dummy sources. The routine used a linear programming formulism to compute which dwell time at each position to irradiate the constrained dose rate at the target surface points whiles minimizing the total volume integrated dose to the patient. The exposure rate and the dose distribution to be confirmed the result of calculation with algorithm were measured with film dosimetry, TLD and small size ion chambers.

The effect of dietary fats of immune response in sublethally irradiated rats

No abstract available.

Effects of Radiofrequency Induced local Hyperthermia on Normal Canine Liver / 대한치료방사선과학회지

In order to assess the effects of radiofrequency-induced local hyperthermia on the normal liver, histopathologic findings and biochemical changes after localized hyperthemia in canine liver were studied. Hyperthermia was externally administered using the Thermotron RF-8 (Yamamoto Vinyter Co., Japan; Capacitive type heating machine) with parallel opposed electrodes. Thirteen dogs were used and allocated into one control group (N=3) and two treatment groups according to the treatment temperature. GroupI(N=5) was heated with 42.5+/-0.5degree C for 30 minutes, and GroupII(N=5) was heated with 45+/-0.5degree C for 15-30 minutes. Samples of liver tissue were obtained through a needle biopsy immediately afterhyperthermia and 7, 14 and 28 days after treatment and examined for SGOT, SGPT and alkaline phosphatase. Although SGOT and SGPT were elevated after hyperthermia in both groups (three of five in each group), there was no liver cell necrosis or hyperthermia related mortality in GroupI. A hydropic swelling of hepatocytes was prominent histologic finding. Hyperthermia with 45degree C for 30 minutes was fatal and showed extensive liver cell necrosis. In conclusion, liver damage day heat of 42.5+/-0.5degree C for 30 minutes is reversible, and liver damage by heat of 45+/-0.5degree C for 30 minutes can be fatal or irreversible. However, these results cannot be applied directly to human trial. Therefore, in order to apply hyperthermic treatment on human liver tumor safely, close observation of temperature with proper thermometry is mandatory. Hyperthermic treatment should be confined to the tumor area while sparing a normal liver as much as possible.

Treatment Result in Advanced T3 and T4 Glottic Carcinoma: YUMC Experience / 대한치료방사선과학회지

Between January 1980 and September 1988, 68 patients with advanced T3 & T4 glottic carcinoma were treated with RT and surgery/RT in the Department of Radiation Oncology, Yonsei Cancer Center and ENT, Yonsei University College of Medicine. The mean age was 60 years old (range 33 to 79 year old). The 34 patients were treated with irradiation alone, and the remaining 34 patients with surgery and irradiation. Initial nodal presentation was 37% (25/68); 31% (11/34) in RT alone group and 41% (14/34) in combined treatment group. The minimum follow-up was 2 years. The local control rate after treatment was 47% in RT alone group and 65% in combined treatment group; 57% for node negative and 27% for node positive patients treated with RT alone; 65% for node negative and 64% for node positive patients treated with combined treatment. The treatment failure was observed in 30 patients; 14 patients for primary local failure, 6 patients for regional nodal failure, 6 patients for local and regional failure, 26 patients for primary failure and/or distant metastasis, and 2 patient for regional failure and/or distant metasasis. The overall 5-year survival rate was 57%; 37% in RT alone group and 76% in combined treatment group; 55% for node negative and 20% for node positive patients treated with RT alone; 73% for node negative and 77% for node positive patients treated with combined treatment. In conclusion, the combined treatment groups in the treatment of advanced T3 and T4 glottic cancer showed the better results in local control rates and 5-year actuarial survival rates than RT alone group. We suggest that total laryngectomy and postoperative RT in the most patients of advanced glottic cancer were performed. However, in cases of node negative patients, RT alone is prefer as a treatment modality over combined surgery and RT since the treatment results were comparable and furthermore functional preservation could be achieved.