Preliminary Results of Stereotactic Radiosurgery Using Stereotactic Body Frame / 대한방사선종양학회지

PURPOSE: To evaluate efficacy and complication of stereotactic radiosurgery using stereotactic body frame. METHODS AND MATERIALS: From December 1997 to June 1999, 11 patients with primary and metastatic tumors were treated with stereotactic radiosurgery using stereotactic body frame(Precision Therapy(TM)). Three patients were treated with primary hepatoma and seven with metastatic tumor from liver, lung, breast, trachea and one with arteriovenous malformation on neck. We used vacuum pillow for immobilization and made skin marker on sternum and tibia area with chest marker and leg marker. Diaphragm control was used for reducing movement by respiration. CT-simulation and treatment planning were performed. Set-up error was checked by CT-Simulator before each treatment. Dose were calculated on the 80~90% isodose of isocenter dose and given consecutive 3 fractions for total dose of 30 Gy (10 Gy/fraction). RESULTS: Median follow-up was 12 months. One patient (9%) showed complete response and four patients (36%) showed partial response and others showed stable disease. Planning target volumes (PTV) ranged from 3 to 111 cc (mean 18.4 cc). Set-up error was within 5 mm in all directions (X, Y, Z axis). There was no complication in all patients. CONCLUSION: In primary and metastatic tumors, stereotactic radiosurgery using stereotactic body frame is very safe, accurate and effective treatment modality.

Clinical Experience of Three Dimensional Conformal Radiation Therapy for Non-Small Cell Lung Cancer / 대한방사선종양학회지

PURPOSE: This prospective study has been conducted to assess the value of three dimensional conformal radiation therapy (3DCRT) for lung cancer and to determine its potential advantage over current treatment approaches. Specific aim of this study were to 1) find the most ideal 3DCRT technique 2) establish the maximum tolerance dose that can be delivered with 3DCRT and 3) identify patients at risk for development of radiation pneumonitis. MATERIALS AND METHODS: Beginning in Nov. 1994, 95 patients with inoperable non-small cell lung cancer (stage I; 4, stage II; 1, stage IIIa; 14, stage IIIb; 76) were entered onto this 3D conformal trial. Areas of known disease and elective nodal areas were initially treated to 45 Gy and then using 3DCRT technique 65 to 70 Gy of total dose were delivered to the gross disease. Sixty nine patients received 65 Gy of total dose and 26 received 70 Gy. Seventy eight patients (82.1%) also received concurrent MVP chemotherapy. 3DCRT plans were compared with 2D plans to assess the adequacy of dose delivery to target volume, dose volume histograms for normal tissue, and normal tissue complication probabilities (NTCP). RESULTS: Most of plans (78/95) were composed of non-coplanar multiple (4-8) fields. Coplanar segmented conformal therapy was used in 17 pateints, choosing the proper gantry angle which minimize normal lung exposure in each segment. 3DCRT gave the full dose to nearly 100% of the gross disease target volume in all patients. The mean NTCP for ipsilateral lung with 3DCRT (range ; 0.17-0.43) was 68% of the mean NTCP with 2D treatment planning (range ; 0.27-0.66). DVH analysis for heart showed that irradiated volume of heart could be significantly reduced by non-coplanar 3D approach especially in the case of left lower lobe lesion. Of 95 patients evaluable for response, 75 (79%), showed major response including 25 (26%) with complete responses and 50 (53%) with partial responses. One and two year overall survivals of stage lll patients were 62.6% and 35.2% respectively. Twenty percent (19/95) of patients had pneumonitis ; Eight patients had grade 1 pneumonitis and 11 other patients had grade 2. Comparison of the average of NTCP for lung showed a significant difference between patients with and without radiation pneumonitis. Average NTCP for patients without complication was 62% of those with complications. CONCLUSIONS: This study showed that non-coplanar multiple fields (4-8) may be one of the ideal plans for 3DCRT for lung cancer. It also suggested that 3DCRT may provide superior delivery of high dose radiation with reduced risk to normal tissue and that NTCP can be used as a guideline for the dose escalation.

Radiation Therapy of Intracranial Germinoma / 대한치료방사선과학회지

PURPOSE: Intracranial germinoma is the most radiocurable tumor of the primary intracranial neoplasm. But, the optimum radiation dose and target volume remain controversial. In this retrospective study, we analysed the spreading pattern at presentation and the pattern of the failure and survival of intracranial germinoma. MATERIALS AND METHODS: From 1989 to 1996, 23 patients were treated for intracranial germinoma at Department of Radiation Oncology. Twenty-one patients were treated at their initial presentation and 2 patients were treated for recurrent disease. Six patients had multiple tumor masses on MRI and 7 patients had ventricular seeding on MRI. The examination of cerebrospinal fluid cytology was done in 15 patients and 3 out of 15 patients had positive cerebrospinal cytology. In tumor marker study of alpha-FP and beta-hCG, 6 patients had mildly elevated beta-hCG in serum or cerebrospinal fluid. Twenty-one patients were treated with whole craniospinal axis irradiation and 2 patients were given whole ventricular radiation therapy. The total dose was ranged between 4500cGy and 5600cGy to primary tumor site (median 5580 cGy). Dose to the entire ventricular system ranged from 1980cGy to 3960 cGy (median 2700cGy) and dose to the spinal axis ranged from 2160cGy to 3900cGy (median 2700cGy). RESULTS: Of 23 patients, 21 patients are alive without evidence of disease for median 4 years follow-up. One patient who had markedly elevated alpha-FP and beta-hCG suffered from persistent disease after radiation therapy and received 2 cycles of chemotherapy. She died 9 months after chemotherapy. One patient who developed ventricular seeding after gamma-knife was treated with whole craniospinal irradiation, he died after 1 year due to probably brain necrosis. The hematologic toxicity of 3 or 4 grade were seen in 7 patients, and patient's endocrinologic dysfunction was not deteriorated after radiation therapy. One patient had been treated with growth hormone replacement due to short stature. CONCLUSIONS: This retrospective study has confirmed the excellent result of radiation therapy in intracranial germinoma. The complication rate during or after radiation therapy is considered within acceptable range. It is necessary to further investigate the optimal dose and treatment volume of radiation therapy. The role of chemotherapy in the treatment of intracranial germinoma should be further investigated.

Radiation Therapy of Nasopharyngeal Carcinoma / 대한치료방사선과학회지

PURPOSE: This is a retrospective study to evaluate the results of radiation therapy and prognostic factors influencing the results in nasopharyngeal carcinoma. MATERIALS AND METHODS: From October 1989 to May 1996, 56 patients were treated for nasopharyngeal carcinoma at Department of Radiation Oncology. According to stage, patients were distributed as follows: stage I (2), II (13), III (11), IV (30). Twenty-eight patients were treated with radiation therapy only, 7 patients were treated with neoadjuvant chemotherapy followed by radiation therapy. Twenty-one patients were treated with radiation therapy and weekly CDDP. After external beam radiotherapy of 60Gy, 46 patients received boost dose with intracavitary radiation and 9 patients with 3D conformal therapy. One patient received boost dose with 2 dimensional photon beam therapy. The tumor dose ranged from 69.4Gy to 86.2Gy with median dose of 74.4Gy. The follow-up period ranged from 5 months to 92 months with a median of 34 months. RESULTS: Forty-seven patients achieved complete response and 8 patients showed partial response. One patient showed minimal response. Patterns of failure were as follows : locoregional recurrence (8) and distant metastasis (18). Among these patients, 2 patients failed locoregionally and distantly. The sites of distant metastasis were bone (8), lung (8) and liver (4). Five years survival rate was 67.2% and 5 years disease-free survival rate was 53.6%. KPS (P=0.005) and response of radiation therapy (P=0.0001) were significant prognostic factors for overall survival. KPS (P=0.02) and response of radiation therapy (P=0.005) were significant prognostic factors for disease-free survival. CONCLUSION: This retrospective study showed that distant metastasis was the predominant pattern of relapse in nasopharyngeal cancer. Neoadjuvantchemotherapy or weekly CDDP did not influence the distant metastasis-free survival. For advanced T stage, 3D conformal therapy provided an improved dose coverage compared to ICR. But further follow-up was needed in patients with 3D conformal therapy to assess the efficacy of this therapy. Development of techniques of radiation therapy to improve locoregional control and of more effective systemic chemotherapy regimen are needed.