• Radiation Oncology Journal
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• v.18 no.4
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• pp.257-264
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• 2000

Purpose: For early stage non-small-cell lung cancer, surgical resection is the treatment of choice. But when the patients are not able to tolerate it because of medical problem and when refuse surgery, radiation therapy is considered an acceptable alternative. We report on the treatment results and the effect of achieving local control of primary tumors on survival end points, and analyze factors that may influence survival and local control. Materials and Method : We reviewed the medical records of 32 patients with medically inoperable non-small cell lung cancer treated at our institution from June, 1987 through June, 1997. All patients had a pathologic diagnosis of non-small cell lung cancer and were not candidate for surgical resection because of either patients refusal (4), old age (2), lung problem (21), chest wail invasion (3) and heart problems (3). In 8 patients, there were more than 2 problems. The median age of the patients was 68 years (ranging from 60 to 86 years). Histologic cell type included souamous (24), adenocarcinoma (6) and unclassiried squamous cell (2). The clinical stages of the patients were 71 in 5, 72 in 25, 73 in 2 patients. Initial tumor size was 3.0 cm in 11, between 3.0 cm and 5.0 cm in 13 and more than 5.0 cm in 8 patients. Ail patients had taken chest x-rays, chest CT, abdomen USG and bone scan. Radiotherapy was delivered using 6 MV or 10 MV linear accelerators. The doses of primary tumor were the ranging from 54.0 Gy to 68.8 Gy (median; 61.2 Gy). The duration of treatment was from 37 days through 64 days (median; 0.5 days) and there was no treatment interruption except 1 patient due to poor general status. In 12 patients, concomitant boost technique was used. There were no neoadjuvant or adjuvant treatments such as surgery or chemotherapy. The period of follow-up was ranging from 2 months through 93 months (median; 23 months). Survival was measured from the date radiation therapy was initiated. Results : The overall survival rate was 44.6$\%$ at 2 years and 24.5$\%$ at 5 years, with the median survival time of 23 months. of the 25 deaths, 7 patients died of intercurrent illness, and cause-specific survival rate was 61.0$\%$ at 2 years and 33.5$\%$ at 5 years. The disease-free survival rate was 38.9$\%$ at 2 years and 28.3$\%$ at 5 years. The local-relapse-free survival rate was 35.1$\%$, 28.1$\%$, respectively. On univariate analysis, tumor size was significant variable of overall survival (p=0.0015, 95$\%$ C.1.; 1.4814-5.2815), disease-free survival (P=0.0022, 95$\%$ C.1., 1.4707-5.7780) and local-relapse-free survival (p=0.0015, 95$\%$ C.1., 1.2910- 4.1197). 7 stage was significant variable of overall survival (p=0.0395, 95$\%$ C.1.; 1.1084-55.9112) and had borderline significance on disease-free survival (p=0.0649, 95$\%$ C.1.; 0.8888-50.7123) and local-relapse-free survival (p=0.0582, 95$\%$ C,1.; 0.9342-52.7755). On multivariate analysis, tumor size had borderline significance on overall survival (p=0.6919, 955 C.1., 0.9610-5.1277) and local-relapse-free survival ( p=0.0585, 95$\%$ C.1.; 0.9720-4.9657). Tumor size was also significant variable of disease-free survival (p=0.0317, 95% C.1.; 1.1028-8.4968). Conclusion : Radical radiotherapy is an effective treatment for small (71 or f3 cm) tumors and can be offered as alternative to surgery in elderly or infirmed patients. But when the size of tumor is larger than 5 cm, there were few long-term survivors treated with radiotherapy alone. The use of hypefractionated radiotherapy, endobronchial boost, radisensitizer and conformal or IMRT should be consider to improve the local control rate and disease-specific survival rate.

• The Journal of Korean Society for Radiation Therapy
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• v.30 no.1_2
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• pp.107-116
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• 2018

Purpose : Intensity-modulated radiation therapy(IMRT) has been widely used for radiation therapy of Prostate Cancer because it can reduce radiation adverse effects on normal tissues and deliver more dose to the Prostate than 3D radiation therapy. Volumetric modulated arc therapy(VMAT) has been widely used due to recent advances in equipment and treatment techniques. VMAT can reduce treatment time by up to 55 % compared to IMRT, minimizing motion error during treatment. Materials and Methods : In this study, compared the MU and DVH values of 10 patients with prostate cancer by classifying them into 4 groups with 5 LN-Prostate groups and 5 Only-Prostate. And DQA measurements were performed using ArcCHECK and MapCHECK. Results : The results of Target and OAR dose distribution of Prostate patients are as follows. $D_{max}$ was in the range of 100~110 % in 4 groups, and more than 110 % of hot spot was not seen. Only-Prostate ($P_1$, $P_2$) without LN had a satisfactory dose distribution for the target dose, but slightly better for 2 arc plan($P_2$) than 1 arc plan($P_1$). The target dose $D_{98%}$ distribution in the LN-Prostate ($P_{L1}$, $P_{L2}$) group showed better 2 arc plan($P_{L2}$) than 1 arc plan($P_{L1}$), But in the case of 1 arc plan($P_{L1}$), the target dose $D_{98%}$ value was not enough. In OAR, the dose distribution of 1 Arc($P_1$) Plan and 2 Arc($P_2$) Plan in the Only-Prostate ($P_1$, $P_2$) Group satisfied the prescribed dose value. But, The dose distribution of 1 arc($P_1$) was slightly higher. In LN-Prostate OAR, 1 Arc($P_{L1}$) Plan showed higher dose than the prescribed dose. The Gamma evaluation pass rate of ArcCHECK and MapCHECK calculated from the DQA measurements was slightly higher than 99 % and the mean error range of the point dose measurements using the CC04 ion chamber was less than 1 %. Conclusion : In this study, Only-Prostate ($P_1$, $P_2$) group, the dose of 2 Arc plan was better. However, considering the treatment time and MU value, 1 Arc treatment method was more suitable. In the LN-Prostate ($P_{L1}$, $P_{L2}$) group, 2 Arc($P_{L2}$) treatment method showed better results and satisfied with Target $D_{98%}$ and OAR prescription dose.

• The Journal of Korean Society for Radiation Therapy
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• v.28 no.2
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• pp.171-178
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• 2016

Purpose : In order to minimize the dose of femoral head as an appropriate treatment plan for rectal cancer radiation therapy, we compare and evaluate the usefulness of 3-field 3D conformal radiation therapy(below 3fCRT), which is a universal treatment method, and 5-field 3D conformal radiation therapy(below 5fCRT), and Volumetric Modulated Arc Therapy (VMAT). Materials and Methods : The 10 cases of rectal cancer that treated with 21EX were enrolled. Those cases were planned by Eclipse(Ver. 10.0.42, Varian, USA), PRO3(Progressive Resolution Optimizer 10.0.28) and AAA(Anisotropic Analytic Algorithm Ver. 10.0.28). 3fCRT and 5fCRT plan has $0^{\circ}$, $270^{\circ}$, $90^{\circ}$ and $0^{\circ}$, $95^{\circ}$, $45^{\circ}$, $315^{\circ}$, $265^{\circ}$ gantry angle, respectively. VMAT plan parameters consisted of 15MV coplanar $360^{\circ}$ 1 arac. Treatment prescription was employed delivering 54Gy to recum in 30 fractions. To minimize the dose difference that shows up randomly on optimizing, VMAT plans were optimized and calculated twice, and normalized to the target V100%=95%. The indexes of evaluation are D of Both femoral head and aceta fossa, total MU, H.I.(Homogeneity index) and C.I.(Conformity index) of the PTV. All VMAT plans were verified by gamma test with portal dosimetry using EPID. Results : D of Rt. femoral head was 53.08 Gy, 50.27 Gy, and 30.92 Gy, respectively, in the order of 3fCRT, 5fCRT, and VMAT treatment plan. Likewise, Lt. Femoral head showed average 53.68 Gy, 51.01 Gy and 29.23 Gy in the same order. D of Rt. aceta fossa was 54.86 Gy, 52.40 Gy, 30.37 Gy, respectively, in the order of 3fCRT, 5fCRT, and VMAT treatment plan. Likewise, Lt. Femoral head showed average 53.68 Gy, 51.01 Gy and 29.23 Gy in the same order. The maximum dose of both femoral head and aceta fossa was higher in the order of 3fCRT, 5fCRT, and VMAT treatment plan. C.I. showed the lowest VMAT treatment plan with an average of 1.64, 1.48, and 0.99 in the order of 3fCRT, 5fCRT, and VMAT treatment plan. There was no significant difference on H.I. of the PTV among three plans. Total MU showed that the VMAT treatment plan used 124.4MU and 299MU more than the 3fCRT and 5fCRT treatment plan, respectively. IMRT verification gamma test results for the VMAT plan passed over 90.0% at 2mm/2%. Conclusion : In rectal cancer treatment, the VMAT plan was shown to be advantageous in most of the evaluation indexes compared to the 3D plan, and the dose of the femoral head was greatly reduced. However, because of practical limitations there may be a case where it is difficult to select a VMAT treatment plan. 5fCRT has the advantage of reducing the dose of the femoral head as compared to the existing 3fCRT, without regard to additional problems. Therefore, not only would it extend survival time but the quality of life in general, if hospitals improved radiation therapy efficiency by selecting the treatment plan in accordance with the hospital's situation.