Quantification Of Primary Tumor Volume Changes During Three Dimensional Conformal Radiotherapy For Non-small-cell Lung Cancer

ObjectiveTo evaluate primary tumor volume,pattern and around normal tissue changes, then to analysis changes basic regulation and regulation curve for patients with non–small-cell lung cancer by using repeat simulation computed tomography(CT) scans during three dimensional conformal radiotherapy; to give reason dose escalation or a decrease of normal tissue exposure for clinical treatment lung cancer.MethodsFourteen patients with histologic or cytologically proven locally advanced non-small-cell lung cancer(stageⅢA–ⅢB) were included in this study from October 2009 until September 2010, a median age of 59.5(range,47–83),12 were male, 2 were female. Radiotherapy was delivered in 2.0~2.2Gy daily fractions to a median dose of 60Gy (range, 58–64), one fraction per day, five fractions per week. All of fourteen patients received three times simulation CT scans. One repeat CT scans were performed at a median dose of 30Gy (range, 26–34) and 50Gy(range, 46–50.6) at two repeat CT scans.ResultsThe average decrease volumes of 0-30Gy,30-50Gy,0-50Gy period were (35.23±43.36),(22.38±22.07),(57.60±56.07)cm3, respectively. The average decrease volumes per day(cm3/d)of 0-30Gy,30-50Gy,0-50Gy period were(1.70±2.10),(1.75±1.48),(1.74±1.77)cm3/d, respectively. The average reduction percentage of 0-30Gy,30-50Gy,0-50Gy period were (25.74±18.69),(17.46±10.98),(43.24±15.72)%, respectively. The average regression rates of 0-30Gy,30-50Gy,0-50Gy period were(1.24±0.95),(1.39±0.79),(1.28±0.48)%/d, respectively. By paired t-test the average decrease volumes,the average decrease volumes per day,the average reduction percentage,the average regression rates of 0-30Gy,30-50Gy period have demonstrated no significant correlations of 14 patients, the T value was 1.21,-0.12,1.18,-0.38, respectively; the P value was 0.25,0.91,0.26,0.71, respectively.ConclusionsThe average regression rates,the average reduction percentage,the average decrease volumes,the average decrease volumes per day of 0-30Gy,30-50Gy period have demonstrated no significant correlations of 14 patients. We observe the average primary tumor volume constantly rates regression during three dimensional conformal radiotherapy for non-small-cell lung cancer. If changes occur, adaptive planning is appropriate to further improve the therapeutic ratio.