High Versus Low Dose-Rate Intracavitary Irradiation for Adenocarcinoma of the Uterine Cervix / 대한방사선종양학회지

PURPOSE: The incidence of adenocarcinoma of the uterine cervix is low. Traditionally, Low Dose R ate (LDR) brachytherapy has been used as a standard modality in the treatment for patients with carcinoma of the uterine cervix. The PURPOSE of this report is to evaluate the effects of the High dose rate (HL)R) brachytherapy in the patients with adenocarcinoma of the uterine cervix compared with the LDR. MATERIALS AND METHODS: From January 1971 to December 1992, 106 patients of adenocarcinoma of uterine cervix were treated with radiation therapy in the Department of Radiation Oncology, Yonsei University with curative intent. LDR brachytherapy was carried out on 35 patients and 7 1 patients w -re treated with HDR brachytherapy. In LDR Group, 8 patients were in stage I, 18 in stage II and 9 in st;ge III. External radiation therapy was delivered with 10 MV X-ray, daily 2 Gy fractionation, total dose 40-46 Gy (median 43 Gy), And LDR Radium intracavitary irradiation was performed with Henschke applicator, 22-59 Gy to point A (median 43 Gy). In HDR Group, there were 16 patients in stage I, 38 in stag 0.05). There was no statistical difference in terms of the 5-year overall survival rate between HDR Group and LDR Group in a denocarcinoma of the uterine cervix. There was 1 1% of late complication rates in LDR Group and 27% in HDR Group. There were no prognostic factors compared HDR with LDR group. The incidence of the late complication rate in HDR Group stage II, III was higher than that in LDR Group ( 16.7% vs. 31.6% in stage II, 11. 1% vs. 35.3% in stage III, p>0.05). Although the incidence of radiation induced late complication rate was higher in HDR Group stage II and III patients than that in the LDR Group, statistical significance was not detected and within acceptable level. CONCLUSION: There was no difference in terms of 5-year survival rate and failure pattern in the patients with adenocarcinoma of the uterine cervix treated with HDR and LDR brachytherapy. Even late complication rates were higher in the HDR group it was an acceptable range. This retrospective study suggests that HDR brachytherapy seems to replace the LDR brachytherapy in the adenocarcinoma of the uterine cervix. However, further studies will be required to refine the dose rate effects.

The Correlation between DNA Ploidy and the Clinicohistologic Findings in Colorectal Cancer / 대한방사선종양학회지

PURPOSE: DNA ploidy pattern was shown to correlate with several clinicohistologic findings in several tumors. Aim of this study was to evaluate the correlation of the clinicohistologic findings in colorectal cancer and the failure pattern in rectosigmoid cancer with DNA ploidy. MATERIALS AND METHODS: DNA flow cytometry using the Hedley methods on paraffin embedded specimen from 117 patients with colorectal cancers after curative resection was performed. We tried to find the correlation between DNA ploidy and various clinicohistologic findings. And then the correlation DNA ploidy and the failure pattern in 75 patients of rectosigmoid cancer was analized. RESULTS: Forty samples (34.2%) from tumors gave aneuploidy histogram. There was no significant difference in the frequency of DNA aneuploidy in terms of age, sex, depth of invasion, location and Dukes stage. But there was a significant correlation between DNA ploidy and the failure rates in Dukes stage B rectosigmoid cancer ( p=0.048). CONCLUSIONS: These findings suggest that DNA ploidy pattern shows the correlation with the treatment failure rates in Dukes stage B rectosigmoid, but not with many other clinicohistologic findings. However, more patients will be needed to disclose these findings.

Photon Energy Dependence of the Sensitivity of LiF TLDs Loaded with Thin Material / 대한방사선종양학회지

PURPOSE: An investigation has been carried out on the factors which affect the response reading of thermoluminescent dosimeters (TLD-100) loaded with thin material in high energy photon. The aim of the study was to assess the energy response of TLD-100 to the therapeutic ranges of photon beam. MATERIALS AND METHODS: In this technique, TLD-100 (abbreviated as TLD) chips and three different thin material (Tin, Gold, and Tissue equivalent plastic plate) which mounted on the TLD chip were used in the clinical photon beam. The thickness of each metal plates was 0.1 mm and TE plastic plate was 1 mm thick. These compared with the photon energy dependence of the sensitivities of TLD (normal chip), TLD loaded with Tin or Gold plate, for the photon energy range 6 MV to 15 MV, which was of interest in radiotherapy. RESULTS: The enhancement of surface dose in the TLD with metal plate was clearly detected. The TLD chips with a Gold plate was found to larger response by a factor of 1.83 in 10 MV photon beam with respect to normal chip. The sensitivity of TLD loaded with Tin was less than that for normal TLD and TLD loaded with Gold. The relative sensitivity of TLD loaded with metal has little energy dependence. CONCLUSION: The good stability and linearity with respect to monitor units of TLD loaded with metal were demonstrated by relative measurements in high energy photon (6~15 MV) beams. The TLD laminated with metals embedded system in solid water phantom is a suitable detector for relative dose measurements in a small beam size and surface dose.

Low Dose Cisplatin as a Radiation Sensitizer in Management of Locally Advanced Squamous Cell Carcinoma of the Uterine Cervix: Evaluation of Acute Toxicity and Early Response / 대한방사선종양학회지

PURPOSE: To evaluate possible acute toxicity and early response of concurrent radiation therapy and low dose daily cisplatin as a radiosensitizer in patients with locally advanced uterine cervical carcinomas. MATERIALS AND METHODS: From December 1996 to January 1999, 38 previously untreated patients with locally advanced squamous cell carcinoma of the uterine cervix (from stage IIB to stage IIIB) were treated at Inha University Hospital. All patients underwent standard pretreatment staging procedures after the initial evaluation by gynecologists and radiation oncologists. Sixteen patients with huge cervical mass (>4 cm) were submitted to the group treated with concurrent radiation therapy and low dose daily cisplatin while the remainder was treated with radiation therapy alone. Radiation therapy consisted of 4500 cGy external beam irradiation to whole pelvis (midline block after 3060 cGy), 900~1000 cGy boost to involved parametrium, and high dose-rate intracavitary brachytherapy (a total dose of 3000~3500 cGy/500 cGy per fraction to point A, twice per week). In the group treated with low dose cisplatin concurrently, 10 mg of daily intravenous cisplatin was given from the 1st day of radiation therapy to the 20th day of radiation therapy. Acute toxicity was measured according to expanded common toxicity criteria of the NCI (C) Clinical Trials. Early response data were analyzed at minimum 4 weeks' follow-up after completion of the treatment protocol. RESULTS: Hematolgic toxicity was more prominent in patients treated with radiation therapy and cisplatin. Six of 16 patients (37.5%) treated with radiation therapy and cisplatin and one of 22 patients (4.5%) treated with radiation therapy alone experienced grade 3 leukopenia. In Fisher's exact test, there was statistically significant difference between two groups regarding leukopenia (P=0.030). There was no apparent difference in the frequency of gastrointestinal and genitourinary toxicity between two groups (P=0.066). Three of 16 patients (18.7%) treated with radiation therapy and cisplatin and two of 22 patients (9.1%) treated with radiation therapy alone experienced more than 5 kg weight loss during the treatment. There was no statistically significant difference on weight loss between two groups (P=0.63). Two patients on each group were not evaluable for the early response because of incomplete treatment. The complete response rate at four weeks' follow-up was 80% (16/20) for the radiation therapy alone group and 78% (11/14) for the radiation therapy and cisplatin group. There was no statistically significant difference in early response between two treatment groups (P=0.126). CONCLUSION: This study led to the conclusion that the hematologic toxicity from the treatment with concurrent radiation therapy and low dose daily cisplatin seems to be more prominent than that from the treatment of radiation therapy alone. There was no grade 4 hematologic toxicity or mortality in both groups. The hematologic toxicity in both treatment groups seems to be well managable medically. Since the risk factors were not balanced between two treatment groups, the direct comparison of early response of both groups was not possible. However, preliminary results regarding early response for patients with bulky cervical tumor mass treated with radiation therapy and low dose daily cisplatin was encouraging. Longer follow-up is necessary to evaluate the survival data. A phase III study is needed to evaluate the efficacy of concurrent daily low dose cisplatin with radiation therapy in bulky cervical cancer.

Evaluation of Usefulness of Portal Image Using Electronic Portal Imaging Device (EPID) in the Patients Who Received Pelvic Radiation Therapy / 대한방사선종양학회지

PURPOSE: To evaluate the usefulness of electronic portal imaging device through objective compare of the images acquired using an EPID and a conventional port film. MATERIAL AND METHODS: From Apr. to Oct. 1997, a total of 150 sets of images from 20 patients who received radiation therapy in the pelvis area were evaluated in the Inha University Hospital and Severance Hospital. A dual image recording technique was devised to obtain both electronic portal images and port film images simultaneously with one treatment course. We did not perform double exposure. Five to ten images were acquired from each patient. All images were acquired from posteroanterior (PA) view except images from two patients. A dose rate of 100-300 MU/min and a 10- MV X-ray beam were used and 2-10 MUs were required to produce a verification image during treatment. Kodak diagnostic film with metal/film imaging cassette which was located on the top of the EPID detector was used for the port film. The source to detector distance was 140 cm. Eight anatomical landmarks (pelvic brim, sacrum, acetabulum, iliopectineal line, symphysis, ischium, obturator foramen, sacroiliac joint) were assessed. Four radiation oncologist joined to evaluate each image. The individual landmarks in the port film or in the EPID were rated - very clear (1), clear (2), visible (3), not clear (4), not visible (5). RESULTS: Using an video camera based EPID system, there was no difference of image quality between no enhanced EPID images and port film images. However, when we provided some change with window level for the portal image, the visibility of the sacrum and obturator foramen was improved in the portal images than in the port film images. All anatomical landmarks were more visible in the portal images than in the port film when we applied the CLAHE mode enhancement. The images acquired using an matrix ion chamber type EPID were also improved image quality after window level adjustment. CONCLUSION: The quality of image acquired using an electronic portal imaging device was comparable to that of the port film. When we used the enhance mode or window level adjustment, the image quality of the EPID was superior to that of the port film. EPID may replace the port film.

Radiotherapy of Supratentorial Primitive Neuroectodermal Tumor / 대한치료방사선과학회지

PURPOSE: To evaluate the efficacy of combined treatment of surgery and chemoradiotherapy for supratentorial primitive neuroectodermal tumors (SPNET) and obtain the prognostic factors and complications. MATERIAL AND METHODS:The age of 18 patients ranged from 1 to 27 years (median=5 years). There were 12 males and 6 females. The extents of surgery were gross total (n=9), subtotal (n=8), biopsy only (n=1). Craniospinal radiotherapy was delivered to all the patients except 2 patients who were treated only with the whole brain and primary lesion. Radiation dose were 3120-5800cGy (median=5460) to primary mass, 1500-4200cGy (median=3600cGy) to the whole brain and 1320-3600cGy (median= 2400 cGy) to the spinal axis. Chemotherapy was done in 13 patients. Median follow-up period was 45 months ranged from 1 to 89 months. RESULTS: Patterns of failure were as follows; local recurrence (1), multiple intracranial recurrence (2), spinal seeding (3), craniospinal seeding (2) and multiple bone metastasis (1). Two of two patients who did not received craniospinal radiotherapy failed at spinal area. All the relapsed cases died at 1 to 13 months after diagnosis of progression. The 2- and 5-year overall survival rates were 61% and 49%, respectively. The age, sex, tumor location did not influence the survival but aggressive resection with combined chemotherapy showed better outcome. Among 9 survivors, complications were detected as radiation necrosis (n=1), hypopituitarism (n=2), cognitive defect (n=1), memory deficit (n=1), growth retardation (n=1). CONCLUSION: To improve the results of treatment of SPNET, maximal surgical resection followed by radiation therapy and chemotherapy is necessary. The extended radiation field including craniospinal axis may reduce the recurrence in spinal axis.

Evaluation of Staging with MR Imaging in the Uterine Cervical Cancer / 대한암학회지

PURPOSE: Uterine cervical carcinoma is the most common cancer in Korean women. We evaluated the accuracy of magnetic resonance (MR) imaging in determining the stage and extent of disease in cervical carcinoma. MATERIALS AND METHODS: From January 1994 through December 1996, in all 35 patients, MR imaging was performed before any operative procedure. With a 1.5T superconducting magnet, TR (repetition time)/TE (echo time) of 483/9msec for T1-weighted images and 3750/98msec for T2-weighted images were used. All patients underwent radical hysterectomy or total abdominal hysterectomy and had detailed histologic evaluation. MR image were reviewed and compared with pathologic findings on the presence of tumor size, depth of stromal invasion and vagina extension. RESULTS: The accuracy of MRI in determination of stage was 74%. Its accuracy was 60% for the assessment of tumor size. Tumor size was underestimated in 6 patients (17%) and overestimated in 8 patients (23%). Tumor infiltration into the stroma was classified as no, partial, complete. The accuracy of MRI in cervical stromal invasion was 66%. CONCLUSION: MR is a relatively promising method for staging and evaluating extent of disease in carcinoma of the uterine cervix.

Endobronchial Brachytherapy for MalignantAirway Obstruction: Low Dose Rate Versus High Dose Rate / 대한치료방사선과학회지

PURPOSE: This is a retrospective study to compare the palliation rates, survival rates and complications of low dose rate and high dose rate endobronchial brachytherapy in the management of malignant airway obstruction. METHODS AND MATERIALS: Forty three consecutive patients with malignant airway compromise from primary or metastatic lung tumors were treated with low dose rate(LDR) endobronchial Iridium-192 insertion (21 patients) between October 1988 and June 1992, and high dose rate(HDR) endobronchial brachytherapy(22 patients) between August 1992 and April 1994 with palliative aim. Flexible fiberoptic bronchoscopy under fluoroscopic control was utilized in all 91 provedures. Twenty seven LDR provedures delivereda dose of 5-7.5 Gy to a 1.0 cm radius respectively. RESULTS: Subjective and objective responses to treatments were evaluated on follow-up examinations by clinical examination, chest x-rays and CT scan of the chest had been demonstrated on 8 LDR patients and 10 HDR patients. CONCLUSION: The technique of LDR and HDR endobronchial brachytherapy is simple and well tolerated procedure with minimal morbidity. It provides excellent palliation by keeping airway patent in these short life-spanned patients.

Extracranial Doses with LIINAC Stereotactic Radiosurgery / 대한치료방사선과학회지

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