| Objective : 1. The aim of this study was to investigate the movement, and the factors that influence such movement of pancreatic lesions and to provide a reference for determination of Interal target volume(ITV) during Stereotactic Body Radiation Therapy. 2. To evaluate the efficacy and safety of Cyber Knife®Stereotactic Body Radiation Therapy treatment for locally advanced pancreatic cancer.Method:1. We implanted 10 gold markers into the inner pancreatic tumors of 10 pancreatic carcinoma patients guided by B-ultrasound, CT, endoscopic ultrasonography or during the tumor resection. The marked motion of pancreatic lesions in the L-R(Left-Right side) 〠A-P(Anterior-Posterior side) and S-I(Superior-Inferior side) directions was measured using 4D-CT scan. By the analysis and processing of 4D workstation, we got ten series of breathing phase from 0-90%. Contoured the outline of the gold markers in Pinnacle planning system, and automatically determined the target centroid position of gold markers.Record the centroid position’s three-dimensional space coordinates of each breath phase and calculated the movement of L- R(Left and Right side), A- P(Anterior-Posterior side) and S- I(Superior- Inferior side) directions. Based on the statistical analysis of the detected movements, we investigated the relevant influencing factors of pancreatic lesions with multinomial linear regression, which include age, height, weight, positon and volume of the tumor. 2. The efficacy of Cyber Knife®treatment was analyzed in 59 locally advanced pancreatic cancer patients treated between October 2006 and September 2014. The median tumor volume was 27.1 ml(13.0-125.145 ml). The median prescribed dose was 45 Gy(35-50Gy),delivered in 5 fractions(3-8 fractions). The overall survival(OS) rates and freedom from local progression(FFLP) rates were estimated using the Kaplan-Meyer survival curve.Results : 1. The 10 patients, 5 men and 5 women, with a median age 66 years(range 28-76 years), height 167.5 cm(range 158-180 cm) and weight 61.4 kg(range 49-74 kg). The lesions, average volume 50.81 ml(range 9.63–125.15 ml),were located in the body of pancreas in 4 cases and in the head of pancreas in 6.Data showed that the mean motion amplitudes of pancreatic lesions were0.16±0.09cm(range 0.06-0.29cm) 〠0.31±0.12cm(range 0.13-0.47cm) and0.72±0.25cm(range 0.31-1.16cm) in L-R〠A-P and S-I side. Motion amplitude was not correlated with the height, weight or age of the patients nor with the location, but the S-I motion amplitude was correlated with the size of the tumor obviously(P<0.05). 2. The median follow-up time for all patients was 10.9 months(3.2-48.7 months) and 15.6 months(3.9-37.6 months) among surviving patients.The median OS was 12.5 months, and the 1-year and 2-year survival rates were53.9% and 35.1%, respectively. The 1-year FFLP rate was 90.8% based on the computed tomography(CT) evaluation. The pain relief rate was 92.5% 2 weeks after the treatment. Grade 1-2 acute and late-stage gastrointestinal(GI) reactions were observed in 61% patients. Grade 1-2 acute and late GI toxicity were observed in 61% of patients. One patient experienced grade 3 toxicity with incomplete intestinal obstruction.Conclusions:1. The motion of pancreatic lesions was mainly influenced by the respiratory motion and has maximal amplitude in the S-I direction. Therefore,motion in the S-I direction should be given a priority consideration while determining the ITV. The tumor volume is the main influence factors affect the respiratory movement range of S-I direction. 2. Excellent clinical efficacy was obtained after treatment of locally advanced pancreatic cancer using Cyber Knife®,with minimal toxicity. |
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