Department of Radiation Oncology, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Korea

Transcription

1 J. Korean Soc Ther Radiol Oncol : Vol. 15, No. 3, September, 1997, Department of Radiation Oncology, AsanMedical Center, College of Medicine, University of Ulsan, Seoul, Korea Purpose:In radiation therapy, NTCP is very important indicator of selecting the optimal treatment plan. In our study, we tried to find out usefullnessof NTCPin lung cancer by comparngthe incidence of radiation pneumonitis with NTCP. Methods and Materials:From August 1993 to December 1994, thirty six patients with locally advanced non-small cell lung cancer were treated by concurrent chemoradiationtherapy. Total dose of radiation therapy was 6480cGy(120cGy, bid) and chemotherapeuticagents were mitomycinc, vinblastine, cisplatin(2 cycles, 4 weeks interval). We evaluated the developmentof radiatio n pneumonitis by CT scan, chest x-ray and clinical symptoms. We used grading system of South Western Oncology Group (SWOG) for radiation pneumonitis. Dose Volume Histograms (DVH) were analyzed for ipsilateraland whole lung. Non uniform DVHwas translated to uniform DVHby effective volume method. With these data, we calculated NTCPfor ipsilateraland whole lung. Finally we compared the clinical results to NTCP. Results:Eight of thritysix patients developed radiation pneumonitis. Of these 8 patients, 6 had grade I severity and 2 had grade II. The average NTCPvalue of the patients who showed radiation pneumonitis was significantlyhigher than that of the patients without pneumonitis (66% vs. 26.4%). But the results of pulmonary function test was not correlated with NTCP. Conclusion:NTCPof lung is very good indicator for selecting rival treatmentplanning in lung cancer. According to the results of NTCP, it may be possible to adjust target volume and optimize target dose. In the near future, we are going to analyze the effect of hyperfractionationand concurrent chemotherapy in addition to NTCP : 388-1

2 KanofskyPerformance Scale(KPS) 34(94%)80 3 (a)7(19%), 3 (b)29(81%) 27(75%) (Table 2). 120cGy. cord dose AP-PA Two oblique POP 3 field technique 6480cGy 3. MotomycinC, Vinblastine,. 3 Cisplatin DVH Computer Tomography(CT) scan Chen 1) Dose slice pixel size cm Volume Histogram (DVH) Brahme2-4), Bush5), Renderplan3-dimensional planning system Fischer6,7), Yaes 8) Tumor Control. NTCPDVH Kutcher Probability(TCP) 12) effective volume method nonuniform Lyman9-11)Kutcher12,13) histogramuniform histogram TD50 Normal Tissue ComplicationProbability(NTCP) Emami14), Lyman Model. (Whole lung) (Radiation (Ipsilaterallung) Pneumonitis) (Fig. 1). DVH, NTCP. (Pulmonary Function Test, PFT) NTCP (Table 1).

3 J. Korean Soc Ther Radiol Oncol : Vol. 15, No. 3, September, 1997, Chest X-ray, Chest CT South West Oncology Groupgrading system. 1 6 Chest CT PFT Chest X-ray Lyman Model 9,10) grade 16 grade 22. NTCP NTCP NTCP (Table (Table 5, Fig. 1). 3, 4). (PFT) FVC, FEV1, DLCo p=0.07, DL/VA

4 (Table 6). DL/VA NTCP (Fig. 2).. partial volumereferencedose. (Fig. 3, Fig. 4)., 5-20% 15). NTCP Reference volume.. Partial volumereference dose 6480cGy Partial volume Mary 16)42 73 Gy( Gy) NTCP

5 J. Korean Soc Ther Radiol Oncol : Vol. 15, No. 3, September, 1997 Computer Applications in Radiation Oncology. University NTCP Press of New England, Hanover, N.H. 1976; Reference dose 6.Fischer JJ, Moulder JE. The steepness of the dose-response curve in radiation therapy. Radiology 1975; 117: FischerDB, FischerJJ.Dose response relationships in (pulmonary function test) Radiotherapy. Application of a logistic regression model. Int J RadiatOncolBiolPhys1977; 2:773 Bronchoalveolarlavage bio-marker 8.YaesRJ.Some implications of the linear quadratic model for tumor control probability. Int J Radiat OncolBiolPhys 17) 1988; 14: Lyman JT. Complication probability as assessed from dose NTCP volume histograms. Rad Res 1985; 104: Lyman JT, WolbarstAB.Opimizationof radiation therapy Rival III:A method of assessing complication probabilities from dose volume histograms. Int J Radiat OncolBiolPhys plan 1987; 13: NTCP 11.Lyman JT, WolbarstA.Optimization of radiation therapy 3 IV:A dose volume histogram reduction algorithm. Int J. RadiatOncolBiolPhys1989; 17: Chen GJY, Austin-Seymour M, Castro JC, etal.dose volume histograms in treatment planning evaluation of carcinoma of the pancreas. In proceedings Eighth International Conference on users of Computers in Radiation Therpy. IEEE ISBNO ; BrahmeA, AgrenAK.Optimal dose distribution for eradication of heterogeneous tumors. ActaOncologica 1987; 26:1-9 3.BrahmeA.Dosimetricprecision requirements in radiation therapy. Proc. of Eighth Int. Conf. on Use of Computers in Radiation therapy 1984; BrahmeA.Dosimetricprecision requirements in radiation therapy. ActaRadiologicaOncology 1984; 23: Bush U, RosenowU.Dose volume relationships. In 12.KutcherGJ, Burman C, Brewster L, etal.histogram reduction method for calculating complication probabilities for 3D treatment planning evaluations. NCI Contract Report for N01-CM , 47695, 44695, KutcherGJ.Evaluation and Scoring of Three Dimensional Treatment Plans. Proc 11th Annual Varian User's Meeting 1988; EmamiB, Lyman J, Brown A, etal.tolerance of normal tissue to therapeutic irradiation. Int J Radiat OncolBiol Phys1991; 21: Mah K, Poon P, Van DykJ, etal.assessment of acute radiation induced pulmonary changes using computed tomography. J CompAssist Tomogr1986; 10: Mary KM, Randall K, Ten H, etal.dose volume histogram and 3D treatment planning evaluation of patients with pneumonitis. Int J Radiat OncolBiolPhys 1994; 28:

6 17.,, ; 43:75-87 = =,, :.,. Dose Volume Histogram(DVH) (Effective Volume Method) (Normal Tissue Complication Probability, NTCP). : , DVH NTCP. 36 MitomycinC, Vinblastine, Cisplatin 2 (120cGy/fx, bid) 6480cGy. CTscan, DVH. Kutcher Effective Volume MethodNonuniform HistogramUniform Histogram, TD50Emami, Lyman NTCP. GradeSWOGToxicity Criteria. : 36 6 Grade I, 2 Grade II. NTCP NTCP , : NTCP NTCP. NTCP (Hyperfractionation). NTCP (Dose escalation).

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