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Objective:To analyze the clinically acceptable and reproducible bladder and rectum volumes of prostate cancer patients during radiotherapy under bladder and bowel preparation, aiming to provide quantitative indicators for bowel and bladder preparation before and after radiotherapy.Methods:Clinical data of 275 prostate cancer patients with strict bladder and bowel preparation and completion of whole course radical radiotherapy at Sun Yat-sen University Cancer Center from April 2015 to December 2020 were retrospectively analyzed. Patients were scanned with cone beam CT (CBCT) before each treatment and the setup error was recorded. Sixty-six patients were selected by simple random sampling and the bladder and rectum on daily CBCT was outlined using MIM software. The relationship between the ratio of daily bladder or rectum volume to the planned bladder or rectum volume (relative value of volume) and setup error was analyzed. Quantitative data were expressed as mean±SD. Normally distributed data were analyzed by paired t-test while non-normally distributed data were assessed by Kruskal-Wallis test.Results:The bladder and rectum volume on planning CT were (370.87±110.04) ml and (59.94±25.07) ml of 275 patients. The bladder and rectum volumes on planning CT were (357.51±107.38) ml and (65.28±35.37) ml respectively of the 66 selected patients with 1611 sets of CBCT images. And the bladder and rectum volumes on daily CBCT were (258.96±120.23) ml and (59.95 ± 30.40) ml. The bladder volume of patients was decreased by 3.59 ml per day on average during the treatment and 0.37 ml for the rectum volume. According to the bladder volume on planning CT, all patients were divided into three groups: <250 ml, 250-450 ml and >450 ml groups. The relative value of volume in the 250-450 ml group during the course of radiotherapy was the smallest. And the setup error in the superior and inferior (SI) direction was (0.28±0.24) cm and (0.19±0.17) cm in the left and right (LR) direction, significantly lower than those in the other two groups (both P≤0.027). According to the rectum volume on planning CT, all patients were divided into four groups: <50 ml, 50-<80 ml, 80-120 ml and >120 ml groups. The <50 ml group had the smallest relative value of volume during radiotherapy, and the setup error in the SI direction was (0.26±0.22) cm and (0.24±0.22) cm in the anterior and posterior (AP) direction, significantly smaller than those in the other groups (both P≤0.003). The setup errors in the SI, LR, AP directions of the enrolled 66 patients were (0.30±0.25) cm, (0.20±0.18) cm and (0.28±0.27) cm, respectively. Among them, the relative value of bladder volume in the AP direction was (0.73±0.37) in the setup error <0.3 cm group, which was statistically different from those in the setup error 0.3-0.5 cm and >0.5 cm groups (both P<0.05). Conclusion:Under the bladder and bowel preparation before planning CT, the appropriate bladder and rectum volumes are in the range of 250-450 ml and <50 ml, which yields higher reproducibility and smaller setup error.
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Objective:To evaluate the efficacy of first-line tyrosine kinase inhibitors (TKI) plus immune checkpoint inhibitors (ICI) in metastatic fumarate hydratase-deficient renal cell carcinoma (FH-deficient RCC).Methods:The data of 87 metastatic FH-deficient RCC patients from West China Hospital ( n=44), Renji Hospital ( n=27) and Sun Yat-sen University Cancer Center (n=16) from Mar 2019 to Aug 2022 were retrospectively analyzed. The median age was 37(30, 47) years, the male to female ratio was 1.9∶1. The median size of tumor was 7.5(5.0, 10.0) cm. Sixty-one patients (70.1%) had germline FH mutations, and 26 patients (29.9%) had somatic FH mutations. Forty-nine patients (56.3%) metastasis disease at initial diagnosis, and 38 patients (43.7%) had metachronous metastasis. The most common site of metastasis was lymph node (41/87, 47.1%), followed by bone (33/87, 37.9%), liver (22/87, 25.3%), and lung (14/87, 16.1%). Fifteen patients (17.2%) had weak expression of FH protein and 59 patients (67.8%) had positive PD-L1 expression. The most common treatments were sintilimab plus axitinib (52/87, 59.8%), followed by pembrolizumab plus cabozantinib (7/87, 8.0%), tirelizumab plus axitinib (6/87, 6.9%), pembrolizumab plus axitinib (5/87, 5.7%), and toripalimab plus axitinib (4/87, 4.6%). Thirteen patients (13/87, 14.9%) received other ICI plus TKI combination treatments. Statistical analysis was conducted using R 4.2.3 software. Kaplan Meier survival curve was used to evaluate survival data, and log-rank test was used to compare differences between treatment groups. Results:The overall objective response rate (ORR) and disease control rate (DCR) of first-line TKI + ICI were 39.1% and 89.7%, respectively. The median progression-free survival (PFS) and overall survival (OS) were 16.5 months and 71.0 months, respectively. For first-line sintilimab plus axitinib, the ORR and DCR were 44.2% and 92.3%, respectively. The median PFS was 17.3 months and the median OS was not reached for this combination treatment. The efficacy of first-line tirelizumab plus axitinib was inferior to other treatment strategies (median PFS: 4.0 vs. 16.6 months, P<0.001; median OS: 22.0 vs. 71.0 months, P=0.043). Subgroup analyses further showed that the efficacy of ICI+ TKI combination therapy was consistent in patients with different clinicopathologic and genomic features. However, patients with liver metastasis had shorter OS than those without liver metastasis (median OS: 26.3 vs. 71.0 months, P=0.021). Conclusion:First-line TKI + ICI is effective for metastatic FH-deficient RCC and can significantly prolong the survival of the patients.
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Objective:To investigate the efficacy of different treatment modes for locoregional recurrence after nephrectomy in patients with renal cell carcinoma.Methods:A total of 106 patients with locoregional recurrence after nephrectomy without distant metastasis (77 males and 29 females) admitted to Sun Yat-sen University Cancer Center from October 2001 to July 2020 were retrospectively analyzed. The median age was 51 (40, 60) years old. Radical nephrectomy was performed in 90 patients with primary tumor and partial nephrectomy was performed in 16 patients. Pathological diagnosis showed that 54 cases were clear cell carcinoma and 52 cases were non-clear cell carcinoma. 53 cases were in stage T 1-2 and 53 cases in stage T 3-4. The median diameter of recurrent lesions was 3.2 (2.0, 6.3) cm, and the median number was 2 (1, 4). The recurrence sites were divided into renal fossa recurrence (33 cases), renal fossa±retroperitoneal lymph node recurrence (38 cases), and intra-abdominal spread (35 cases). The median duration from primary surgery to local recurrence was 14.8 (7.3, 35.8) months. Two treatment groups were identified as systemic therapy alone (Group A) and local therapy with or without systemic therapy (Group B). The Kaplan-Meier method was used to compare the progression free survival (PFS) and overall survival (OS) between Group A and Group B. The Cox model was used to perform univariate and multivariate analysis. Results:Of all the 106 patients, 33 patients were in Group A and 73 patients were in Group B. In Group A, 29 patients (87.9%) received targeted therapy, and 4 patients (12.1%) received targeted therapy combined with immunotherapy. In Group B, 34 patients (46.6%) received surgery or ablation and 39 patients (53.4%) received SBRT, of which 62 patients (84.9%) received concurrent systemic therapy. Among them, 58 patients (93.5%) received targeted therapy, and 4 patients (6.5%) received targeted therapy combined with immunotherapy. The median follow-up period was 29.0 (15.4, 45.9) months, 64 patients progressed on tumor including 28 patients died. The median PFS and OS were 15.6 (7.1, 35.2) months and 66.9 (37.8, not reached) months. The median PFS of Group A and Group B were 7.6(5.0, 17.2)months and 22.2(9.6, 63.9)months respectively ( P=0.001), median OS of Group A and Group B were 45.7 (23.4, 62.8)months and 71.0(50.6, not reached)months respectively, and the 2-year OS were 70.6% and 85.5% in Group A and Group B respectively ( P=0.023). The univariate analysis showed local therapy with or without systemic therapy was significantly reduced 56% risk of tumor progression ( HR=0.44, P=0.003) and reduced 60% risk of death ( HR=0.40, P=0.028). The multivariate analysis showed that the OS was associated with ECOG score( HR=10.20, 95% CI 4.13-25.30, P<0.001)and local therapy( HR=0.23, 95% CI 0.09-0.58, P=0.002). Conclusion:Compared with systemic therapy alone, local therapy with or without systemic therapy can effectively improve the PFS and OS of patients with locoregional recurrence after nephrectomy.
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Radical prostatectomy(RP)was commonly used in localized prostate cancer. For patients with adverse pathological features (APF) after RP, it was controversial about choosing adjuvant radiotherapy or salvage radiotherapy (SRT). Recent studies have found that early salvage radiotherapy(ESRT) had both the same cancer control and reduced overtreatment compared to adjuvant radiotherapy. Nomogram and Gene Classifier(GC) could predict the risk of recurrence after RP and contribute to choose adjuvant radiotherapy or ESRT. PSMA PET/CT was more sensitive to detect distant metastasis after biochemical recurrence, which was helpful to decide whether to implement SRT.
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Objective:To provide evidence for the selection of fixation devices and CTV to PTV margins (M ptv) in precision radiotherapy for pelvic tumors by analyzing three fixation devices in precision radiotherapy for prostate cancer. Methods:From April 2015 to December 2020, 133 prostate cancer patients treated with pelvic drainage area irradiation in our center were retrospectively analyzed. The patients were fixed with 1.2m vacuum bag (n=39), 1.8m vacuum bag (n=44) and personalized prone plate by our center (n=50). Each patient was asked to complete our bowel and bladder preparation process before positioning and radiotherapy. The registration of CBCT to planned CT before each treatment adopted the same registration box and algorithm. Setup errors in the SI, LR and AP directions under qualified bowel and bladder conditions were recorded. Setup errors in three directions under three fixation devices and corresponding M ptv values were analyzed. The correlation between setup errors with age and body mass index (BMI) was analyzed. Results:Analysis of 3333 setup errors data showed: in the SI and LR directions, the mean setup errors of 1.2m vacuum bag (3.26mm, 2.34mm) were greater than those of 1.8m vacuum bag (2.51mm, P<0.001; 1.90mm, P<0.001), and personalized prone plate (3.07mm, P=0.066; 2.10 mm, P=0.009). In the AP direction, the mean setup errors of 1.2m vacuum bag (supine)(2.20mm) were smaller than those of 1.8m vacuum bag (3.33mm, P<0.001) and personalized prone plate (3.61mm, P<0.001). The setup errors of 1.8m vacuum bag in all directions were smaller than those of personalized prone plate (P≤0.028). According to Van Herk's expansion formula, the M ptv of 1.2m vacuum bag in three directions was approximately 4 mm. The M ptv of 1.8m vacuum bag and personalized prone plate in the SI and LR directions was approximately 3 mm, and more than 5 mm in the AP direction. The setup errors were not correlated with age or BMI. Conclusions:From the setup errors results of three devices, 1.8m vacuum bag is the best, followed by personalized prone plate. And supine position is better than prone position in the AP direction.
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Objective:To investigate the prognosis after salvage radiotherapy with or without hormone therapy for prostate cancer.Methods:From May 2014 to December 2020, 248 patients undergoing salvage radiotherapy due to prostate-specific antigen (PSA)persistence or biochemical progression after radical prostatectomy at Sun Yat-sen University Cancer Center (n=157) and West China Hospital, Sichuan University (n=91) were analyzed. Median age was 66 (45-78) years old. Median PSA was 23.50 (0.18-845.00) ng/ml. The number of PSA persistence and biochemical progression were 143 (59%) and 105 (42%). The number of pT 2, pT 3a, pT 3b, pT 4, and unknown T stage was 99, 49, 78, 15 and 7 cases.The number of N 0, N 1 and unknown N stage was 153, 44 and 51 cases. 165 cases had positive surgical margin. Gleason score of 6, 7, 8, >8 score and unknown was in 12, 104, 34, 90 and 8 patients. Early and late salvage radiotherapy was performed in 117 and 131 patients, and 70 patients (28%) were CRPC. Hormone therapy was used combined with radiotherapy in 182 patients (73%). PSA decline after radiotherapy was compared with Chi-squre test. Kaplan-Meier method and log-rank test were used to compare progression free-survival (PFS)after radiotherapy. Univariate and multivariate analyses of PFS were performed using Cox proportional hazards model. Early salvage radiotherapy was defined as PSA≤0.5 ng/ml before radiotherapy, and late salvage radiotherapy was defined as PSA>0.5ng/ml. Results:PSA response (PSA decline ≥50%) rate was 94% (233/248), and 82% (203/248) patients had PSA decline ≥ 90%. Twelve (5%) patients had rising PSA after completing radiotherapy, but only 4 (2%) had real progression. The median PFS was 69 months (95% CI 68-70), and 3-year and 5-year PFS rate were 80% and 67%. PFS of PSA persistence and biochemical progression were similar ( HR =0.71, 95% CI 0.37-1.37, P=0.311). Compared with late salvage radiotherapy, early salvage radiotherapy had better PFS [69 (95% CI 68-70) vs. 59 (95% CI 44-74) months, P<0.001]. Compared with hormone sensitive, castration-resistant was associated with worse PFS (5-year PFS rate 74% vs. 51%, P<0.001). In multivariate analysis, Gleason score>8, castration-resistant and late salvage radiotherapy were unfavorable prognostic factors. Conclusions:In patients receiving salvage radiotherapy with or without hormone therapy for PSA persistence and biochemical progression after radical prostatectomy, high PSA level before radiotherapy and castration resistant is associated with poor prognosis.
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Objective@#To report the experience on the multi-disciplinary management of metastatic renal cell (mRCC) patients in a single center.@*Methods@#Data of 168 mRCC patients treated by multi-disciplinary team (MDT) at Sun Yat-sen University Cancer Center from December 2007 to February 2019 was retrospectively analyzed.Three treatment groups were identified, including 76 patients with 55 males and 21 females, received anti-angiogenic agents alone (Group A), 66 patients with 55 males and 11 males, received anti-angiogenic agents plus local therapy (Group B)and 26 patients, with 19 males and 7 females, received anti-angiogenic agents plus immunotherapy and local therapy (Group C). The Sunitinib, Sorafenib, Axitinib were chosen for the TKI. The Pembrolizumab was used for immunotherapy. The stereotactic body radiation therapy and surgical excision were considered as the local therapy. The study aims to compare the age, gender, IMDC score, pathology, nbephrectomy, adverse events, progression-free survival and overall survival (OS).@*Results@#Of all patients, the median follow-up duration was 23 months (ranging 6-117 cmonths). The PFS was 18.3 months and median OS was 33.5 months. The 2 years and 5 years survival rate was 66% and 35%, respectively. The median OS of Group A, B and C were 29.8 months, 44.6 months and not reached. 2y-OS was 58%, 67% and 89%, while 5y-OS 12%, 46% and 57%.There was no difference in age, gender, IMDC score, pathology, synchronous metastases or nephterectomy between the three groups. The prognostic result in TKI based combination therapy was superior to TKI therapy alone, which the 5y-OS was 51% and 11%, respectively. The prognostic result in group C's moderate-high risk mRCC patients was superior to group A and B. The median OS in TKI+ DC and CIK+ Pembrolizumab was 49.1 months and 53.1 months. On univariate analyses, IMDC score, nephrectomy and treatment group was associated with OS (P<0.05). On multivariate analyses, treatment group, nephrectomy was associated with OS (P<0.05). The risk of death of Group C decreased about 60% [HR 0.39 (0.17, 0.89), P=0.026]. 78 (46.4%) patients on TKI alone and 16 (61.5%) patients treated with TKI plus immunotherapy had Grade 3 or 4 adverse events. 16 (20.3%) patients had Clavien Ⅲ-Ⅳ toxicity after surgical procedures. 6 (5.7%) patients had Grade 3 toxiciy after SBRT.@*Conclusions@#Patients treated with combined therapy had better survival than those treated with anti-angiogenic agents alone. MDT approach could bring survival benefit to mRCC patients.
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Objective:To evaluate the efficacy and safety of switch from prednisone (AA+ P) to dexamethasone (AA+ D) in metastatic castration-resistant prostate cancer patients (mCRPC) progressing on abiraterone plus prednisone.Methods:Between November 2016 and December 2019, 46 mCRPC patients were switched to AA+ D after progression on AA+ P at Sun Yet-sen University Cancer center. Median age was 72 years(50 to 89 years), with median androgen deprivation therapy (ADT) duration 14.6 months(2.1 to 168.5 months). PSA level at the time of diagnosis, the initiation of AA+ P treatment, the time of switch were 258.9 ng/ml, 56.6 ng/ml, 25.1 ng/ml, respectively. 42 (91.3%), 12(26.1%), 7(15.2%) patients had bone metastasis, lymph node metastasis, visceral metastasis, respectively. 28 patients had Gleason score ≥8, and 11 patients had Gleason score<8. The primary endpoint was progression free-survival (PFS). Secondary endpoints included PSA response rate of PSA decline ≥50% and ≥30% and safety. Patients were divided into different risk level groups according to PSA level at the time of switch and PFS on AA+ P.Results:The median follow-up of 46 patients was 4.9 months, 40 patients progressed at the last follow-up, the treatment was terminated in 1 patient because of cerebral infarction, 5 patients were still on the treatment of AA+ D. Median PFS on AA+ D of 46 patients was 3.7 (1.6-24.1) months. A total of 12 (26.1%) patients showed a PSA decline≥50% after treatment with AA+ D, and 21 (45.7%) patients showed a PSA decline ≥30%. The median PFS was 8.5 (2.7-24.1) and 3.0 (1.6-17.8) months for patients with PSA decline≥50% and PSA didn’t decline ≥50%, respectively. Four factors below were significantly associated with a longer PFS on AA+ D after steroid switch in univariate analysis: lower PSA level at the time of switch (<30 ng/ml, HR=0.30, 95% CI 0.14-0.64, P=0.002), longer ADT sensitivity duration (≥18 months, HR=0.55, 95% CI 0.28-1.06, P=0.045), longer AA+ P treatment PFS (≥8 months, HR=0.36, 95% CI 0.18-0.72, P=0.004), and greater PSA decline on AA+ D (≥50%, HR=0.30, 95% CI 0.17-0.75, P=0.007). The above mentioned factors were also independent prognostic factors associated with better PFS on AA+ D after steroid switch in multivariate analysis. Treatment with AA+ D was well tolerated in all patients, with no grade 3/4 toxicity reported. Conclusions:Switching from prednisone to dexamethasone is effective and safe in mCRPC patients progressing on abiraterone plus prednisone. Patients with lower PSA level at the time of switch, longer ADT sensitivity duration, longer AA+ P treatment PFS and greater PSA decline on AA+ D might gain better efficacy.
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Adjuvant therapy is the supplemental treatment to radical prostatectomy (RP) aiming to decrease the risk of relapse, including adjuvant androgen deprivation therapy, adjuvant radiation therapy (ART) and adjuvant chemotherapy. The 2020 version of the EAU guideline updated with a new RCT of ART to emphasize the importance of ART in high-risk patients, and to recommend that RT should be given to the pelvic lymphatics and the prostatic fossa for the pN 1 patients.
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Objective:To evaluate the efficacy and safety of Tyrosine Kinase Inhibitors (TKIs) combined with stereotactic body radiation therapy(SBRT) in the treatment of renal cell carcinoma (RCC) patients with bone metastasis.Methods:The clinical data of 80 RCC patients with bone metastasis in Sun Yat-sen University Cancer Center from April 2010 to April 2020 were analyzed retrospectively. Among them, 64 patients were medium or high risk according to the International Metastatic Renal Cell Carcinoma Database Consortium(IMDC) score. Twenty-four patients received TKI therapy alone(Group A), and the other 56 cases received TKIs combined with SBRT to bone metastastic lesions (Group B).Results:The median follow-up period was 20.7 months (4.8-115.6 months), 70 patients received second or third-line targeted drug therapy, and 4 patients in group A and 15 patients in group B received TKI plus immunotherapy. Fifty-four patients had symptoms of bone pain before radiotherapy, 46 patients were satisfied with the analgesic effect after SBRT treatment. Twelve patients got complete response (CR) after bone lesions, and 32 patients achieved partial response (PR). Forty patients died of disease progression during follow-up. The median OS was: 20.7 months vs not reached(Group A vs. Group B), and the 2-y OS and 5-y OS were 50% vs. 62%, and 19% vs. 56%, respectively ( P=0.006). There were only 2 patients (3.6%) had grade 3 SBRT related adverse events. Conclusions:SBRT combined with TKIs improved the quality of life and prolonged the overall survival of RCC patients with bone metastasis.
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Objective To report the experience on the multi-disciplinary management of metastatic renal cell (mRCC) patients in a single center.Methods Data of 168 mRCC patients treated by multidisciplinary team (MDT) at Sun Yat-sen University Cancer Center from December 2007 to February 2019 was retrospectively analyzed.Three treatment groups were identified,including 76 patients with 55 males and 21 females,received anti-angiogenic agents alone (Group A),66 patients with 55 males and 11 males,received anti-angiogenic agents plus local therapy (Group B)and 26 patients,with 19 males and 7 females,received anti-angiogenic agents plus immunotherapy and local therapy (Group C).The Sunitinib,Sorafenib,Axitinib were chosen for the TKI.The Pembrolizumab was used for immunotherapy.The stereotactic body radiation therapy and surgical excision were considered as the local therapy.The study aims to compare the age,gender,IMDC score,pathology,nbephrectomy,adverse events,progression-free survival and overall survival (OS).Results Of all patients,the median follow-up duration was 23 months (ranging 6-117 cmonths).The PFS was 18.3 months and median OS was 33.5 months.The 2 years and 5 years survival rate was 66％ and 35％,respectively.The median OS of Group A,B and C were 29.8 months,44.6 months and not reached.2y-OS was 58％,67％ and 89％,while 5y-OS 12％,46％ and 57％.There was no difference in age,gender,IMDC score,pathology,synchronous metastases or nephterectomy between the three groups.The prognostic result in TKI based combination therapy was superior to TKI therapy alone,which the 5y-OS was 51％ and 11％,respectively.The prognostic result in group C's moderate-high risk mRCC patients was superior to group A and B.The median OS in TKI + DC and CIK + Pembrolizumab was 49.1 months and 53.1 months.On univariate analyses,IMDC score,nephrectomy and treatment group was associated with OS (P ＜ O.05).On multivariate analyses,treatment group,nephrectomy was associated with OS (P ＜ O.05).The risk of death of Group C decreased about 60％ [HR O.39 (0.17,0.89),P =O.026].78 (46.4％)patients on TKI alone and 16 (61.5％) patients treated with TKI plus immunotherapy had Grade 3 or 4 adverse events.16 (20.3％) patients had Clavien IⅢ-V toxicity after surgical procedures.6 (5.7％) patients had Grade 3 toxiciy after SBRT.Conclusions Patients treated with combined therapy had better survival than those treated with anti-angiogenic agents alone.MDT approach could bring survival benefit to mRCC patients.
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Objective:To evaluate the preliminary clinical efficacy and safety of stereotactic body radiation therapy (SBRT) in combination with targeted therapy for metastatic renal cell carcinoma (mRCC).Methods:Clinical data of 58 patients with mRCC who were treated with SBRT in combination with targeted therapy in Sun Yat-sen University Cancer Center from June 2013 to December 2018 were retrospectively analyzed. Among them, 79.3% patients were classified as intermediate or high risk according to International Metastatic Renal Cell Carcinoma Database Consortium Criteria. The median biologically equivalent dose (BED) was 147 Gy (67 to 238 Gy).Results:Overall, 32, 13, 7, 5 and 1 patients received SBRT for 1, 2, 3, 4 and 6 metastatic sites (105 lesions) and 71.4% of them were bone lesions. Targeted therapy was continued during SBRT. With a median follow-up of 9.4 months (range 2.7 to 40.1 months), 18 patients died. The 1-year local control rate was 97.4%. The 1-year progression-free survival was 50.3%. The 1-and 2-year overall survival was 72% and 53%. Approximately 85% patients experienced pain relief after SBRT. Patients who achieved complete or partial response after SBRT obtained better overall survival than those with stable disease or disease progression (1-year overall survival: 83% vs. 48%, P=0.021). In the whole cohort, 6 cases developed Grade Ⅲ adverse events, 4 of which were Grade Ⅲ myelosuppression, 1 case of Grade Ⅲ neuropathy and 1 case of radiation-induced skin injury. Conclusion:Preliminary study reveals that combined use of targeted therapy and SBRT is an efficacious and safe treatment of advanced mRCC.
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Objective:The aim of the study is to investigate the inter-observer and intra-observer precision in manually segmentation of organs-at-risk(OARs) for cervical cancer on the basis of MR image, and to preliminarily explore sequence selection designed for radiotherapy planning.Methods:Thirty cervical cancer patients scanned by MR-sim from 2016 to 2018 in the department of radiotherapy of Sun Yat-sen university cancer center were retrospectively analyzed. T1WI, T1dixonc and T2WI sequence from MR-simulator were selected and imported into Monaco planning system. Manual segmentation of 5 organs-at-risk (bladder, rectum, anal canal, and left/ right femoral head) was done by 2 independent experienced physicians on three sequences acquired from these patients. A month later, the second segmentation of the OARs in the T1WI sequence was done by one of the two physicians. Dice similarity coefficient (DSC), Hausdorff distance (HD) and position difference(Δ x, Δ y, Δ z) of each OAR were used to analyze the robustness of inter-observer and intra-observer segmentation OARs. Results:The HD values of five OARs segmentation by the two physicians in T1WI, T1dixonc and T2WI sequences and the same physician in T1WI at different time were all less than 2 mm; the position differences were less than 5 mm. The DSC values, HD values and difference position values of the two physician and the same physician at different time was positively correlated with the volume of OARs ( R=0.178-0.582, P<0.05). Due to the small volume of the anal canal (7.385±1.555) cm 3, the DSC values were less than 0.7 and the performance was slightly worse. The average DSC values of other OARs were all greater than 0.82. Comparing the DSC, HD and position differences of OARs in the three sequences, DSC values of rectum, left / right femoral head and bladder, HD values of left/right femoral head and rectum, and Δ z axis difference of anal canal and right femoral head of T1WI sequence were better than T1dixonc ( t=-3.116-3.604, P<0.05); DSC value of rectum and HD value of anal canal in T1WI sequence were better than T2WI sequence( t= 2.934, 3.677, P<0.05 ); T1dixonc sequence rectal DSC, right femoral head Δ z axis difference were slightly better than T2WI( t=6.806, 2.130, P<0.05 ). T2WI sequence bone tissue (left/right femoral head) stability was better than T1WI, T1dixonc, and the difference was statistically significant ( t=-6.580-6.542, P<0.05). Conclusions:From three index of DSC, HD and position difference, the robustness of inter-observer and intra-observer segmentation of bladder, rectum and femoral head are fine based on MR sequence, followed by anal canal. In addition, the robustness of OARs segmentation by T1WI sequence is better than that of T1dixonc and T2WI sequence.
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External beam radiotherapy which is one of the major treatment options for patients with prostate cancer,has entered an accurate radiation era,with the advancement of radiation technology and the consensus of target volume definition recently.Clinical control of prostate cancer has been improved dramatically with the saccurate delivery of dose escalation.Image-guided radiotherapy,proton therapy and hypofractionated radiation therapy are the research direction for better control.