ABSTRACT
Objective To evaluate the clinical efficacy and toxicity of intensity-modulated radiation therapy (IMRT) following prostatectomy for elderly patients with prostate cancer.Methods Ninety-eight prostate cancer patients receiving IMRT after prostatectomy were included in this study.The median age was 68 years old.The number of patients with low-,middle-and high-risk prostate cancer was 10,21 and 67,respectively.Two patients had oligometastases (pelvic bone metastases).Sixty-four patients were treated with IMRT combined with endocrine therapy.Among them,43 cases received adjuvant volumetric modulated arc therapy (VMAT),and 55 patients received salvage IMRT.The median radiotherapy dose was 72 Gy for the tumor bed.Twenty-nine patients received radiotherapy of the pelvic node region with a median dose of 50 Gy.Results The median follow-up time was 40 months.The 5-year overall survival (OS),biochemical recurrence-free survival (BRFS) and local control (LC) were 90％,76％ and 100％,respectively.The OS (88.8％ vs.90.8％,P=0.94),BRFS (75.9％ vs.71％,P=0.79) or LC (100％ vs.100％,P=0.32) did not significantly differ between the adjuvant and salvage radiotherapy groups,respectively.The incidence of grade Ⅰ-Ⅱ late rectal toxicities was 24.1％,and no ≥ grade 3 late toxicity was observed.The incidence of grade 1-2 late bladder toxicities was 29.9％,and 3.4％ for grade 3.Conclusion IMRT following prostatectomy yields high clinical efficacy and slight late toxicities in elderly patients with prostate cancer.
ABSTRACT
Objective To systematically compare the efficacy of three-dimensional conformal radiotherapy (3D-CRT) versus intensity-modulated radiotherapy (IMRT) in the treatment of prostate cancer (PCa).Methods Clinical comparative studies of IMRT and 3D-CRT in the treatment of PCa were collected from PubMed, EMBASE, China National Knowledge Infrastructure (CNKI), and Wanfang Data after two independent researchers developed the strategy and inclusion and exclusion criteria for the literature search.Articles published up to February 2017 were searched for, and the languages of publications were restricted to English and Chinese.Clinical meta-analysis of the data from the relevant studies was performed using the RevMan5.3 software.Results A total of 15 relevant retrospective cohort studies were collected from the databases in strict accordance to the search strategy and inclusion and excluding criteria.There were 4608 PCa patients, including 2229 in the IMRT group and 2379 in the 3D-CRT group.IMRT and 3D-CRT had similar adverse effects in terms of early-stage (odds ratio[OR]=0.77, 95% confidence interval[CI]:0.43-1.40, P=0.390) and late-stage (OR=0.75, 95%CI:0.55-1.04, P=0.080) urinary tract injury.However, IMRT led to reduced early-stage (OR=0.47, 95%CI:0.27-0.82, P=0.008) and late-stage (OR=0.52, 95%CI:0.35-0.78, P=0.001) intestinal injury compared with 3D-CRT.Meanwhile, the biochemical recurrence-free survival rate was also significantly higher in the IMRT group than in the 3D-CRT group (OR=1.87, 95%CI:1.51-2.32, P=0.000).Conclusions IMRT is more protective against intestinal injury with a higher biochemical recurrence-free survival rate compared with 3D-CRT during the treatment of PCa.
ABSTRACT
Objective To analyze the data from intensity-modulated radiotherapy ( IMRT) for prostate cancer guided by kilovoltage cone-beam computed tomography (CBCT), and to provide a clinical basis for selecting the optimal image registration method and reasonable target volume margins.Methods A total of 16 patients with prostate cancer who received radical IMRT were enrolled, and CBCT for online position verification was performed 214 times.The images were obtained after conventional skin marking and laser alignment, and automatic registration, bone registration, soft tissue registration, and manual registration were performed for CBCT images and planned CT images.The differences between these four registration methods were evaluated, and the margins for extending clinical target volume into planning target volume (PTV) were calculated.Results The setup errors in left-right, anterior-posterior, and cranial-caudal directions for automatic registration, bone registration, soft tissue registration, and manual registration were-0.6±2.8 mm/-0.6±4.5 mm/-0.6±3.8 mm,-0.7±2.7 mm/-0.9±4.5 mm/-0.8±4.1 mm,-0.8± 2.6 mm/-0.3±4.4 mm/-1.1±4.0 mm, and-0.6±2.9 mm/-0.7±5.1 mm/-0.9±3.9 mm, respectively. There were no significant differences between the four registration methods.The margins for extension in the left-right, anterior-posterior, and cranial-caudal directions were calculated as 4.7 mm, 5.2 mm, and 6.5 mm, respectively.Conclusions With a comprehensive consideration of various factors, a default setting of automatic registration and manual fine adjustment is appropriate for CBCT-guided radiotherapy for prostate cancer.The margins for extension in the left-right, anterior-posterior, and cranial-caudal directions are 4.7 mm, 5.2 mm, and 6.5 mm, respectively.
ABSTRACT
Objective To observe the motions of the rectum and bladder by image?guided radiotherapy ( IGRT) and to analyze their impact on treatment. Methods Eighteen patients with prostate cancer undergoing intensity?modulated radiotherapy ( IMRT) were enrolled in the study and 247 cone?beam computed tomography ( CBCT) images were obtained from this study. The clinical target volume, bladder, and rectum were contoured on all simulated CT and CBCT to examine their volume and position changes. The dose distributions were recalculated based on the data of the x?, y?, and z?axis setup errors. The doses to planning target volume ( PTV) and organs at risk were calculated in the replanning, and their impact on treatment was analyzed. Comparison of the planning and replanning results was made by paired t?test. The effects of displacements and volumes of the bladder and rectum on target doses were analyzed by Pearson correlation method. Results Great changes in the volumes of the bladder and rectum were observed during the treatment. For the planning and replanning results, PTVD95% was 7777. 37 cGy vs. 7628. 56 cGy ( P=0. 027), PTV Dmin was 87. 91 cGy vs. 83. 35 cGy (P=0. 000), and RVP was 5. 89% vs. 8. 31%(P=0. 000). There were correlations between PTVD95% and the motions of the bladder and rectum, with correlation coefficients of 0. 296 and 0. 177, respectively. The correlation coefficient between rectal volume and PTVD95% was 0. 115, indicating a certain correlation. There is a certain correlation between and PTV Dmin and bladder volume, with a correlation coefficient of?0. 128. Conclusions The recovery of the state during localization for the bladder and rectum, especially the latter, has great significance to ensure the target dose and reduce exposure of the rectum in the IMRT for prostate cancer.
ABSTRACT
Objective To evaluate the role of equivalent uniform dose (EUD) in planning optimization of intensity-modulated radiotherapy (IMRT) for prostate cancer.Methods Ten patients with prostate cancer were randomly selected who treated with IMRT.For these patients,the treatment plans were designed with dose-volume objectives.Based on these plans,new plans were designed through replacing the dose-volume objectives with maximum EUD for rectum,bladder and small bowel,while keeping the dosevolume objectives unchanged.Comparison was made between the new plans and the former cones by paired t-test.Results The conformity index of planning target volume was better with EUD optimization compared to dose-volume (1.00 ± 0.04 ∶ 0.94 ± 0.04,t =3.80,P =0.04).The D53,D30 and Dicm3 for rectum was better with EUD optimization compared to dose-volume (24.4 ± 2.7 ∶ 25.5 ± 2.6,t =-3.82,P =0.004,34.1 ±4.3∶39.1±2.1,t=-3.80,P=0.004 and51.4±1.0∶51.8±0.9,t=-2.42,P=0.039),with V10,V20 for bladder and V10,V20,V30,V40 for small bowel also better with EUD optimization (92.2 ±6.2∶99.4±1.1,t=-4.28,P=0.002;70.7±5.7∶78.7±6.3,t=-3.10,P=0.013 and 62.2±30.2∶74.7 ±30.0,t =-4.18,P =0.002;34.3 ±26.3∶46.5 ±30.9,t =-5.46,P =0.000;17.1 ±17.0∶25.1 ±22.6,t=-3.52,P=0.007;10.6± 11.5∶ 15.6± 16.1,t=-2.64,P=0.030).Conclusions The conformity index of planning target volume is better with EUD optimization compared to dose-volume.And the dose to rectum,bladder and small bowel can be reduced through optimization with EUD optimization compared to dose-volume.
ABSTRACT
Objective To prospectively evaluate the efficacy and toxicity of hypofractionated intensity-modulated radiotherapy (IMRT) for prostate cancer.MethodsFifty-two consecutive patients with localized prostate cancer were enrolled in this study between Feb.2009 and Mar.2011.All patients received hypofractionated IMRT (2.7 Gy/fx,25 fractions,total 67.5 Gy) to the prostate and seminal vesicles.32 high risk patients also received prophylactic irradiation to the pelvic lymph nodes concurrently (2 Gy/fx,25 fractions).Imaging-guided radiotherapy was employed in 35 patients.Androgen deprivation therapy was adopted in 48 of 52 patients.ResultsAfter a median follow-up of 13 months,the mean prostate specific antigen (PSA) was reduced from (40.3 ± 36.6) ng/ml before treatment to (0.5 ± 1.7)ng/ml at the last follow-up.By the time of last follow-up,2 patients (4％) failed.One had PSA failure and the other had both PSA failure and pelvic lymph node relapse.25％ of the patients experienced grade 2 acute gastrointestinal (GI) toxicity and 4％ experienced grade 3 GI toxicity.Acute grade 2 and grade 3genitourinary ( GU ) toxicity occurred in 15％ and 2％,respectively.The incidence of late grade 2 and grade 3 GI toxicity was 17％ and 0％,respectively.Late grade 2 and 3 GU toxicity was 8％ and 2％.The potency was unable to evaluate because most of the patients received androgen deprivation therapy.Conclusions The short-term PSA-free survival after 2.7 Gy/fx,25 fractions' hypofractionated IMRT for localized prostate cancer is favorable,and the acute and late GI and GU toxicity are acceptable.A longer time follow-up is warranted to ascertain the long term efficacy and safety of this regimen.
ABSTRACT
Objective To investigate the influence of endorectal balloon on normal tissue dosimetry in prostate cancer patients treated with intensity-modulated radiation therapy (IMRT). Methods Ten patients with prostate cancer were included and each had two sets of planning CT-scans:one with and one without an air-filled endorectal balloon. Target volumes and organs at risk ( rectum, bladder,femoral heads)were contoured on the 20 CT scans and IMRT plannings were performed. The prescription dose was 78 Gy to 95％ of planning target volume. The percentage of volume of organs at risk ( without or with endorectal balloon) receiving more than 10 Gy, 20 Gy, 30 Gy, 40 Gy, 50 Gy, 60 Gy, 70 Gy and 75 Cy (V10 - V70 ,in increments of 10 Gy, and V75 ) were analyzed. Results The V1o - V60 0f rectum with endorectal balloon were 75. 5％ , 52. 6％ , 35. 3％ , 26. 1％, 19. 6％ , 14. 2％ , and those without endorectal balloon were 82. 2％ , 62. 8％ , 43. 9％ , 31. 4％ , 24. 0％ , 17. 1％ , respectively ( X2 = g. 46, P< 0. 01 ). Use of endorectal balloon significantly reduced the dose to the rectum ( v10 - V60 ) . The V70 and V75 of rectum with endorectal balloon were 9. 1％ and 8. 2％; and those without endorectal balloon were 9. 9％ and 6. 2％ respectively ( X2 = 1. 82,P＞0. 05) . The difference was not significant. There were no significant differences in the dose to bladder,left and right femoral head between patients with and without endorectal balloon.Conclusions Endorectal balloon can significantly decrease the medium and low dose volume of rectum for prostate cancer patients treated with IMRT, which may reduce the rectal toxicity.
ABSTRACT
Objective With the Monte Carlo method to recaleulate the IMRT dose distributions from four TPS to provide a platform for independent comparison and evaluation of the plan quality.These results wiU help make a clinical decision as which TPS will be used for prostate IMRT planning.Methods Eleven prostate cancer cases were planned with the Corvus,Xio,Pinnacle and Eclipse TPS.The plans were recalculated bv Monte Cado using leaf sequences and MUs for individual plans.Dose-volume-histograms and isodose distributions were compared.Other quantities such as Dmin(the minimum dose received by 99% of CTV/PTV),Dmax(the maximum dose received by 1%of CTV/PTV),V110%,V105%,V95%(the volume of CTV/PTV receiving 110%,105%.95% of the prescription dose),the volume of rectum and bladder receiving>65 Gy and>40 Gy,and the volume of femur receiving>50 Gy were evaluated.Total segments and MUs were also compared.Results The Monte Carlo results agreed with the dose distributions from the TPS to within 3%/3 mm.The Xio,Pinnacle and Eclipse plans show less target dose heterogeneity and lower V65 and V40 for the rectum and bladder compared to the Corvus plans.The PTV Dmin is about 2 Gy lower for Xio plans than others while the Corvus plans have slightly lower female head V50(0.03%and 0.58%)than others.The Corvus plans require significantly most segments(187.8)and MUs(1264.7)to deliver and the Pinnacle plans require fewest segments(82.4)and MUs(703.6).Conclusions We have tested an independent Monte Carlo dose catculation system for dose reconstruction and plan evaluation.This system provides a platform for the fair comparison and evaluation of treatment plans to facilitate clinical decision making in selecting a TPS and beam delivery system for particular treatment sites.
ABSTRACT
Objective To restrospectively investigate clinical outcomes and prognositic factors in localized prostate cancer treated with neoadjuvant endocrine therapy followed by intensity modulated radiotherapy (IMRT). Methods Between March 2003 and October 2008, 54 localized prostate cancer treated by IMRT were recruited. All patients had received endocrine therapy before IMRT. The endocrine therapy included surgical castration or medical castration in combination with antiandrogens. The target of IMRT was the prostate and seminal vesicles with or without pelvis. The biochemical failure was defined according to the phoenix definition. By using the risk grouping standard proposed by D'Amico, patients were divided into three groups: low-risk group (n = 5), intermediate-risk group (n = 12), and high-risk group (n = 37). Kaplan-Meier method was used to calculate the overall survival rate. Prognostic factors were analyzed by univariate and multiple Cox regression analysis. Results The follow-up rate was 98%. The number of patients under follow-up was 39 at 3 years and 25 at 5 years. Potential prognostic factors, including risk groups, mode of endocrine therapy, time of endocrine therapy, phoenix grouping before IMRT, the prostate specific antigen doubling time (PSADT) before radiotherapy, PSA value before IMRT, interval of endocrine therapy and IMRT, irradiation region, and irradiation dose were analyzed by survival analysis. In univariate analysis, time of endocrine therapy (75 % vs 95 %, χ~2= 6. 45, P = 0. 011), phoenix grouping before IMRT (87% vs 96%, χ~2 = 4. 36, P = 0. 037), interval of endocrine therapy and IMRT (80% vs 95% ,χ~2= 11.60,P= 0. 001) ,irradiationdose(75% vs 91% ,χ~2=5.92,P= 0. 015) were statisticallysignificant prognostic factors for3 - year overall survival , and risk groups (85 vs 53 vs 29 , χ~2= 6. 40,P =0. 041) and PSADT before IMRT (62 vs 120, U =24. 50,P =0. 003) were significant factors for the median survival time. In the multiple Cox regression model, only time of endocrine therapy and phoenix grouping before IMRT were significantly related to the overall survival. The 3-year overall survival rates in patients with endocrine therapy less than 3 months versus more than 3 months were 75% versus 95% (χ~2= 5.45, P= 0.020). The 5-year overall survival rates in patients with biochemical failure versus nobiochemieal failure was 71% versus 92% (χ~2= 8.83 , P= 0.003) Conclusions Neoadjuvant endocrine therapy should last at least three months. Intensity modulate radiotherapy should start before biochemical failure after the endocrine therapy.
ABSTRACT
Objective To explore the influence of computed tomography (CT) and magnetic resonance imaging (MRI) fusing technique on target volume and dosimetrics of normal tissues in intensity modulated radiotherapy (IMRT) for prostate carcinoma.Methods Ten patients with pathologically diagnosed moderate-high risk localized prostate carcinoma were enrolled in this study.CT and MRI images were collected.Same image slices of the prostate, seminal vesicles, rectum and bladder were anatomically delineated using image fusing software.Clinical target volume (CTV) was defined as the prostate plus seminal vesicles.IMRT treatment planning was designed basing on CT and MRI images, respectively.Differences of CTV volume and dose volume histogram of rectum and bladder between the two image groups were analyzed.Results The mean volume of CTV on CT and MRI images was 84.03 cm3 and 53.53 cm3,respectively (t =2.47,P=0.024).The V50, V60 and V70 of rectum were 30.28%, 19.13%, 9.53% on MRI and 37.03%, 24.99% and 14.55% on CT images, respectively, with significent difference (t =2.71,P=0.014 for V50; t =2.83,P=0.011 for V60; t=3.19,P=0.005 for V70).The maximal dose of bladder was 81.10 Gy on MRI and 82.45 Gy on CT, respectively(t=2.41,P=0.027).Conclusions By using image fusing technique, the mean volume of the prostate plus seminal vesicles delineated on MRI image is smaller as compared to CT image.The volume of the rectum receiving high irradiation dose can be reduced when MRI was used to delineate CTV compared to CT image.
ABSTRACT
Objective To assess set-up errors measured with kilovoltage cone-beam CT (KV-CBCT), and the impact of online corrections on margins required to account for set-up variability during IMRT for patients with prostate cancer. Methods Seven patients with prostate cancer undergoing IMRT were enrolled onto the study. The KV-CBCT scans were acquired at least twice weekly. After initial set-up using the skin marks, a CBCT scan was acquired and registered with the planning CT to determine the setup errors using an auto grey-scale registration software. Corrections would be made by moving the table if the setup errors were considered clinically significant ( i. e. , ＞ 2 mm). A second CBCT scan was acquired immediately after the corrections to evaluate the residual error. PTV margins were derived to account for the measured set-up errors and residual errors determined for this group of patients. Results 197 KV-CBCT images in total were acquired. The random and systematic positioning errors and calculated PTV margins without correction in mm were:a) Lateral 3. 1,2. 1,9. 3;b) Longitudinal 1.5, 1.8, 5. 1 ;c) Vertical 4. 2,3.7, 13.0. The random and systematic positioning errors and calculated PTV margin with correction in mm were:a) Lateral 1.1,0. 9, 3.4;b) Longitudinal 0. 7, 1.1, 2. 5;c) Vertical 1.1, 1.3, 3.7. Conclusions With the guidance of online KV-CBCT, set-up errors could be reduced significantly for patients with prostate cancer receiving IMRT. The margin required after online CBCT correction for the patients enrolled in the study would be appoximatively 3-4 mm.