Long-term effectiveness and safety of image-based,transperineal combined intracavitary and interstitial brachytherapy in treatment of locally advanced cervical cancer

PurposeThe aim of the study was to evaluate the impact of image-based combined intracavitary-interstitial brachytherapy (IC-ISBT) using a transperineal template in locally advanced cervical cancer treatment.Methods and MaterialsA total of 94 patients of cervical cancer stage IIB-IVA underwent image-based transperineal interstitial brachytherapy without tandem (ISBT) or with tandem (IC-ISBT) between June 2008 and June 2018 at our institution. After pelvic chemoradiation, 42 patients underwent ISBT and 52 IC-ISBT. Dosimetric data, clinical response, and toxicity records of these patients were reviewed.ResultsClinical stage distribution was as follows: IIB: 22.4% (21), IIIA: 10.6% (10), IIIB: 56.4% (53), and IVA: 10.6% (10). Mean high-risk clinical target volume was 75.72 cc, and mean cumulative equivalent of 2 Gy per fraction for high-risk clinical target volume was 81 Gy. The median followup was 35.5 months. Overall 3- and 5-year local control, disease-free survival (DFS), and overall survival (OS) were 84% and 84%, 69.1% and 62.9%, and 80.9% and 71.5%, respectively. Local control (90.4% vs. 76.2%; p = 0.048) and DFS (78.8% vs. 57.1%; p = 0.04) were significantly better in the patients of IC-ISBT arm. IC-ISBT (hazard ratio: 0.763; 95% confidence interval 0.217, 1.38; p = 0.046) and D90 dose >85 Gy (hazard ratio: 0.957; 95% confidence interval 0.927, 1.07; p = 0.037) were predictors of better DFS on univariate analysis. Overall survival was not affected significantly by any of the factors. Grade 3 and 4 late complications were recorded in 3.2% (3) of patients and were similar in both arms (p = 0.86). However, the mean rectum 2 cc dose was significantly lower in the IC-ISBT arm (p = 0.038).ConclusionsCombined IC-ISBT is a safe and effective approach to treat ICBT unsuitable cases. It integrates the benefits of ICBT to the adaptability of ISBT around various targets and should be practiced whenever feasible to provide superior outcomes in locally advanced cervical cancer.     

局部晚期宫颈癌腔内放疗联合组织间插植的剂量学研究

目的 比较局部晚期宫颈癌单纯腔内放疗与腔内联合组织间插植放疗的剂量学差异。方法 2016年5月—2017年3月局部晚期宫颈癌患者共35例,均行根治性放疗,治疗方法为外照射+腔内联合组织间插植放疗。调强放射治疗处方剂量为46.8~50.4 Gy/26~28次,1.8 Gy/次。腔内联合组织间插植放疗剂量为7 Gy/次,1次/周,共4次。同一患者首先置入三管式后装放疗施源器,采集CT图像制定治疗计划,取出三管式施源器后,置入宫腔管并植入插植针,再次采集图像制定放疗计划。分别评价比较两组计划中靶区及危及器官的受照剂量差别。结果 共制定212次后装放疗计划,其中单纯腔内治疗计划106例,腔内联合组织间插植治疗计划106例。腔内联合组织间插植放疗组计划较单纯腔内放疗组的靶区剂量明显升高,高危临床靶区（CTV）的D₉₀、中危CTV的D₉₀均显著增高（t=-6.01、-2.73,P<0.05）,膀胱、直肠、乙状结肠的D_{2 cm³}显著降低（t=3.07、4.52、2.91,P<0.05）。结论 局部晚期宫颈癌应用腔内联合插植放疗可以明显提高靶区剂量,并降低危及器官膀胱、直肠和乙状结肠的受照剂量。     

Predicting the necessity of adding catheters to intracavitary brachytherapy for women undergoing definitive chemoradiation for locally advanced cervical cancer

PurposeTo identify if baseline patient or magnetic resonance imaging (MRI) features can predict which women are at risk for inadequate tumor coverage with only intracavitary tandem and ovoid (T + O) brachytherapy and to correlate tumor coverage with clinical outcomes.Methods and MaterialsWe performed a retrospective study of 50 women with cervical cancer treated with chemoradiation at a single institution between January 2014 and December 2015. All patients had a 3T-MRI performed at baseline (MRI1) and at the completion of external beam radiation therapy (MRI2). Gross tumor volume initial (GTV-T_init) was measured on MRI1 and high-risk clinical tissue volume (CTV_HR) on MRI2. CTV_HR extending beyond point A was classified as too large for adequate coverage with T + O and requiring interstitial needles. Multivariate analysis was performed to determine predictive factors of inadequate coverage. Kaplan–Meier and Cox Regression were performed to correlate inadequate coverage with outcomes.ResultsMean patient age was 49.2 ± 13.2 years, and 84% had Federation of Gynecology and Obstetrics IIB/IIIB disease. Forty-two percent of women were estimated to have inadequate tumor coverage with T + O brachytherapy. The GTV-T_init volume and dimensions (superior-inferior, left-right, anterior-posterior) on MRI1 were all important predictive factors of inadequate coverage on multivariate analysis. Receiver operating characteristics curves identified optimal thresholds of superior-inferior ≥ 4.5 cm (area under the curve [AUC] = 0.718), left-right ≥ 4.5 cm (AUC = 0.745), anterior-posterior ≥ 5.0 cm (AUC = 0.767), and GTV-T_init ≥ 85 cm³ (AUC = 0.842). Patients with inadequate coverage had worse clinical outcomes.ConclusionsBaseline MRI tumor size may predict inadequate CTV_HR coverage at the time of brachytherapy (i.e., the need for interstitial needles). This may help identify a subset of women requiring early referral to adequately resourced centers to improve clinical outcomes.     

三种不同优化方法在局部晚期宫颈癌腔内联合组织间插植近距离治疗计划中的剂量学比较

目的 比较分析局部晚期宫颈癌腔内联合组织间插植近距离治疗计划3种优化方法的剂量学差异。方法 回顾性选取局部晚期宫颈癌患者20例,对每例患者根据不同优化方法,分别制定3种计划,分别为手动计划组,基于图形优化;逆向1计划组,基于模拟退火优化算法;逆向2计划组,在逆向1组基础上增加了靶区（CTV）最大剂量限定。比较计划中CTV的体积剂量参数V₂₀₀、V₁₅₀、V₁₀₀、D₁₀₀、D₉₀、均匀性指数（HI）,以及直肠、膀胱、乙状结肠的剂量参数D_{0.1 cm³}、D_{1 cm³}、D_{2 cm³}。结果 CTV方面,手动组和2个逆向组的D₁₀₀参数差异无统计学意义（P>0.05）,但2个逆向组的V₂₀₀、V₁₅₀、V₁₀₀、HI参数明显优于手动组（t=-3.422~9.910,P<0.05）。逆向1组的V₁₀₀和D₁₀₀优于逆向2组（t=7.238、5.032,P<0.05）。危及器官（OARs）方面,与手动组相比,2个逆向组中直肠、膀胱、乙状结肠的D_{0.1 cm3}、D_{1 cm³}和D_{2 cm³}明显降低（t=2.235~5.819,P<0.05）。结论 对于局部晚期宫颈癌腔内联合组织间插植技术,基于3组优化方法的计划均能满足临床需求,且使用逆向优化方法保证了靶区剂量覆盖,同时减少直肠、膀胱、乙状结肠的最大受量。     

Clinical outcomes using image-guided interstitial brachytherapy for definitive cervical cancer patients with high-risk clinical target volumes greater than 30 cc

PurposeGiven the limited data using an interstitial approach with 3D-based planning for definitive cervical cancer utilizing the GEC-ESTRO defined high-risk clinical target volume (HR-CTV), we reviewed our institutional experience of cervical cancer patients with HR-CTVs ≥ 30 cc to determine whether our clinical and toxicity outcomes are acceptable.MethodsA retrospective review of 37 cervical cancer patients with high-risk clinical target volumes (HR-CTVs) ≥30 cc treated with interstitial image-guided brachytherapy (IS IGBT) was performed. All patients received external beam radiotherapy to a median dose of 45 Gy, followed by IS IGBT delivered in a single implant to a median dose of 6 Gy × 5 fractions. Median HR-CTV was 59 cc. A median HR-CTV D₉₀ of 87.44 Gy was achieved. Kaplan–Meier method was used to evaluate local control (LC), distant control, and overall survival (OS), with stratification by overall treatment time (OTT) ≤ 7 or >7 weeks.ResultsMedian followup was 17 months. The estimated 2-year LC, distant control, and OS were 77.6% (confidence interval [CI]: 63.8–94.5%), 56.8% (CI: 41.3–78.1%), and 54.4% (CI: 39.4–75%), respectively. The 2-year LC for OTT ≤7 weeks and >7 weeks were 100% and 58.3%, respectively (p = 0.026). The 2-year OS for OTT ≤7 weeks and >7 weeks were 77.8% and 38%, respectively (p = 0.021).DiscussionsIS IGBT can achieve a high D₉₀ to the HR-CTV even in the setting of large-volume disease and results in a favorable LC and toxicity profile. OTT > 7 weeks is associated with significant decrease in LC and OS.ConclusionsEfforts should be made to complete whole treatment within 7 weeks as this is associated with improved clinical outcomes.     

宫颈癌腔内联合组织间插植近距离治疗优化算法剂量学分析研究

目的在宫颈癌腔内联合组织间插植近距离治疗(IC/ISBT)中, 基于剂量学及生物学模型的帮助, 进行图形优化(GO)、模拟退火逆向计划优化算法(IPSA)和混合逆向计划优化算法(HIPO)的比较分析, 为宫颈癌IC/ISBT治疗优化方法的选择提供依据。方法选取65例接受影像引导下IC/ISBT的宫颈癌患者。所有患者后装治疗计划分别采用GO、IPSA、HIPO优化的方式制定3次, 处方剂量高危临床靶区体积(HRCTV)D90均为6 Gy。针对3种优化方案的用时、剂量-体积参数及放射生物学差异, 采用非参数Friedman检验以及非参数Wilcoxon秩检验进行比较分析。结果逆向计划优化耗时均较正向计划耗时短, 时间分别是GO 135.03 s、IPSA 46.53 s、HIPO 98.36 s, 肿瘤靶区剂量中高剂量照射的V150%(53.66%)在HIPO计划中略高, 而高剂量照射的V200%(30.29%)在GO计划中更高。GO的适形度指数(CI)(0.91)较其他计划更好, 差异具有统计学意义(χ2=69.98, P<0.001)。HIPO计划的膀胱与直肠的D1 cm3、D2...     

Combined intracavitary and interstitial brachytherapy of cervical cancer using the novel hybrid applicator Venezia: Clinical feasibility and initial results

PurposeTo report on first-in-human experience and the initial clinical results using the hybrid applicator Venezia (Elekta, Sweden) in the treatment of patients with locally advanced cervical cancer.Material and MethodsBetween March, 2017, and February, 2018, a total of 40 fractions were performed on patients undergoing definitive chemoradiation and brachytherapy (BT) for cervical cancer. A plan comparison was conducted evaluating the hybrid applicator with the clinically used intracavitary and interstitial (IC/IS) BT against a standard plan prescribed to Point A and a manually optimized plan using only intracavitary (IC) BT. Overall 80 treatment plans were retrospectively generated.ResultsThe clinical use of the hybrid applicator system proved to be feasible in all 40 treatment fractions. The applicator consists of the IC tandem and two lunar-shaped ovoids forming a ring that serves as a template for defined parallel and oblique (12°) needle insertion. MRI preplanning was performed the day before the implant. One to six needles were placed per fraction, and overall a total of 66 needles were used. No complications such as bleeding or organ penetration occurred due to needle placement. Significant differences in IC/IS, Point A, and IC plans were derived for dose application to the target volume; D₉₀ high-risk clinical target volume was 90.7 vs. 88.1 vs. 80.8 Gy (p = 0.008). Likewise, sparing of organs at risk differed significantly for bladder D_2cc 79.4 vs. 91.8 vs. 79.2 Gy (p = 0.03) and rectum D_2cc 58.7 vs. 67.3 vs. 62.5 Gy (p = 0.03).ConclusionThe clinical application of the Venezia applicator is feasible and allows significantly improved dose coverage while at the same time sufficiently sparing organs at risk.     

宫颈癌腔内联合组织间插植近距离后装治疗中IPSA和HIPO逆向优化算法的比较分析

目的 比较宫颈癌腔内联合组织间插植三维后装计划中模拟退火逆向优化（IPSA）和混合逆向优化（HIPO）剂量分布的差异,为宫颈癌腔内联合组织间插植后装治疗逆向计划优化方法的选择提供依据。方法 选取2016年12月至2017年5月于河北省沧州中西医结合医院43例宫颈癌患者资料,所有患者原后装治疗计划采用IPSA优化,基于原图像信息,给定同样的初始约束条件,不进行手动优化,直接计算IPSA和HIPO计划,对高危靶区（HR-CTV）剂量体积参数D₉₀、D₁₀₀、V_100%,以及均匀性指数（HI）、适形指数（CI）、危及器官（OAR）（膀胱、直肠和乙状结肠）D_{2 cm³}的数据进行评价。结果 两组间HR-CTV的D₉₀、D₁₀₀以及CI剂量差异无统计学意义（P>0.05）,但HIPO组HR-CTV的V_100%为（87.72±0.49）%;HI为（0.51±0.08）,明显高于IPSA组的（85.01±0.55）%,HI（0.42±0.06）,差异具有统计学意义（t=2.54、3.02,P<0.05）。对于OAR,与IPSA计划相比,HIPO计划中膀胱的D_{2 cm³}（3.42±0.17）Gy,直肠的D_{2 cm³}（3.04±0.37）Gy,明显低于IPSA计划膀胱的D_{2 cm³}（3.57±0.28）Gy,直肠的D_{2 cm³}（3.21±0.48）Gy,差异具有统计学意义（t=0.27、0.19,P<0.05）。乙状结肠D_{2 cm³}剂量两者差异无统计学意义。结论 在宫颈癌腔内联合组织间插植后装治疗中,采用HIPO优化比IPSA优化可以获得更好的靶区HI以及减少膀胱和直肠的受照剂量。     

Three-dimensional image-guided combined intracavitary and interstitial high-dose-rate brachytherapy in cervical cancer: A systematic review

PurposeTo evaluate the local control and toxicities of three-dimensional image-guided combined intracavitary and interstitial (IC/IS) high-dose-rate brachytherapy (BT) in cervical cancer through a systematic review.Methods and MaterialsA systematic review of relevant studies was performed through the PubMed, Web of Science, and Cochrane Library databases through May 10, 2020. Articles reporting on IC/IS technology, volumetric doses to high-risk clinical target volume (HR-CTV) and organs at risk (OARs), tumor control and/or treatment-related side effects were identified. The key information, including the type of applicator, implantation technology, characteristics of implantation, volumetric doses, tumor control, and/or treatment-related side effects, was extracted. A probit model analysis between HR-CTV D90 and tumor local control was performed.ResultsTwelve studies encompassing 520 patients were included in the probit model between HR-CTV D90 and the local control rate. The probit model showed a significant relationship between the HR-CTV D90 value and the local control probability, p = 0.003. The prescribed dose of 85 Gy_EQD2,10 would in theory warrant an 87.4% (95% confidence interval 82.5%–90.5%) local control rate.ConclusionIC/IS BT is an appropriate method to achieve a high therapeutic ratio for tumors with large volumes or poor responses after external irradiation in cervical cancer. The probit model showed that the dose escalation of HR-CTV D90 was helpful to improve the local tumor control rate.     

模拟退火逆向优化算法在宫腔管联合插植针的宫颈癌三维后装腔内放疗中的应用

目的 探讨模拟退火逆向优化算法（IPSA）在以插植针为施源器的宫颈癌三维后装腔内放疗中的应用效果。方法 以2016年10月至2018年7月接受根治性外照射及腔内联合组织间插植的局部晚期宫颈癌患者60例为研究对象,其中宫腔管联合1~4根插植针的患者各15例。在每例患者的同一套CT图像上,分别用正向的图形优化（GRO）方式和IPSA完成两种放疗计划,采用配对t检验分析两种计划方式的剂量学差异。结果 IPSA计划的D₉₀、V₁₀₀均高于GRO计划（t=-4.742、-4.823,P<0.05）,但靶区一致性指数（CI）和靶区适形指数（COIN）略低于GRO计划（t=9.642、8.783,P<0.05）。两组计划的靶区高量（V₁₅₀、V₂₀₀、V₃₀₀）比较,差异无统计学意义（P>0.05）。两组计划的膀胱、直肠D_{2 cm³}相近（P>0.05）。宫腔管联合1根插植针时,IPSA较GRO的平均D₉₀只提高了4 cGy （P>0.05）;但随着插植针管数的增加,IPSA相比于GRO,D₉₀提高的幅度也逐渐增加;当增加到4根插植针时,IPSA较GRO的平均D₉₀增加了14 cGy （t=-3.180,P<0.05）。与GRO相比,IPSA的V₁₀₀提高的幅度同样随着插植针管数的增加而逐渐增加。结论 在以宫腔管联合插植针为施源器的宫颈癌三维后装治疗中,相比于GRO计划,IPSA计划在未增加靶区高量和危及器官剂量的情况下,可以提高靶区的覆盖度（D₉₀、V₁₀₀）,且随着插植针管数的增多,IPSA较GRO在提高靶区覆盖度方面的优势也更为明显。     

不同HR-CTV下单纯腔内治疗与腔内联合组织间插植治疗在宫颈癌三维后装治疗中的对比研究

目的 研究不同高危临床靶体积（HR-CTV）下单纯腔内治疗与腔内联合组织间插植（腔内+插植）治疗技术在宫颈癌三维后装治疗中的剂量学差异,并探讨HR-CTV是否存在阈值。 方法 回顾性分析2019年10月至2021年2月于广西医科大学第四附属医院接受根治性放疗的100例中晚期宫颈癌患者的临床资料,年龄35~63岁,中位年龄51岁。根据后装治疗技术不同将患者分为单纯腔内治疗组（45例）、腔内+插植治疗组（55例）。按患者每个计划的HR-CTV大小分为6个体积范围进行分析,即HR-CTV≤40 cm3、40 cm33、50 cm33、60 cm33、70 cm33、HR-CTV>80 cm3。 采用独立样本t检验比较2种后装治疗技术在不同体积范围内的靶区和危及器官（OAR）的剂量学参数。 结果 当HR-CTV≤40 cm3时,单纯腔内治疗组的靶区剂量（D90、D100）、靶区覆盖度（V100）及靶区高量（D50、V150、V200）均高于腔内+插植治疗组,且差异均有统计学意义（t=2.826~3.927,均P<0.05）,但靶区适形指数（CI）、OAR膀胱和直肠D2 cm3（2 cm3的OAR体积接受的最低照射剂量）的差异均无统计学意义（t=0.186、1.871、0.258,均P>0.05）。当70 cm33和HR-CTV>80 cm3时,腔内+插植治疗组的靶区剂量（D90、D100）、靶区覆盖度（V100）、CI、OAR直肠和膀胱D2 cm3剂量均显著优于单纯腔内治疗组,且差异均有统计学意义（t=−6.872~3.782,均P<0.05）,而2种治疗技术的靶区高量（D50、V150、V200）相近,差异无统计学意义（t=0.613~1.918,均P>0.05）。当40 cm33时,2组的靶区剂量（D90、D100）、靶区覆盖度（V100 ）以及直肠D2 cm3的差异均无统计学意义（t=−1.759~0.710,均P>0.05）,但腔内+插植治疗组的CI显著优于单纯腔内治疗组,且差异均有统计学意义（t=−2.590、−4.577、−3.144,均P<0.05）。 结论 对于小体积靶区（≤40 cm3）,单纯腔内治疗技术在不增加OAR剂量的情况下能更好地提高靶区剂量和靶区内高剂量体积;当靶区体积较大特别是>70 cm3时,腔内+插植治疗技术能在显著提高靶区处方剂量和适形度的同时更好地保护OAR。     

Practically achievable maximum high-risk clinical target volume doses in MRI-guided intracavitary brachytherapy for cervical cancer: A planning study

PurposeTo explore maximum high-risk clinical target volume (HR-CTV) doses that can be practically achieved when organs at risk (OARs; bladder, rectum, and sigmoid) doses are allowed to equal current recommended thresholds in MRI-based intracavitary brachytherapy (BT) planning for cervical cancer.Methods and MaterialsPlanning MRI sets were retrieved for 21 patients who received pulsed-dose-rate BT boost. Plans were generated using manual optimization (MO) by adjusting dwell positions and times to obtain the prescribed HR-CTV isodose that includes 90% of target (D₉₀) coverage of 35 Gy while limiting OAR doses to below recommended tolerances (prescribed dose target [TGT] plans). Additional planning was performed with automatic volume optimization (VO) to evaluate target coverage relative to the MO plans. The MO and VO approaches were then applied with the objective of obtaining the highest possible HR-CTV coverage when OAR doses were allowed to equal threshold tolerance values (maximized [MAX] plans). A two-tailed paired t test was performed to determine the statistical significance of the results; significance level set at p < 0.013.ResultsMO and VO planning techniques could conform HR-CTV D₉₀ to the prescribed dose quite similarly for TGT plans. Using the MAX approach, the HR-CTV D₉₀ could be increased by 30% and 37% for MO and VO, respectively, without exceeding OAR thresholds. Sigmoid and often rectum were the dose-limiting structures during MAX planning.ConclusionsSimple differences in the approach to volumetric MRI-based cervix BT treatment planning can impact HR-CTV D₉₀. Consequently, dose escalation for MRI-guided cervix BT appears feasible in this manner should clinical circumstances warrant.     

Radiobiological optimization comparison between pulse-dose-rate and high-dose-rate brachytherapy in patients with locally advanced cervical cancer

PurposeOnly scarce data are available on the possibility to include radiobiological optimization as part of the dosimetric process in cervical cancer treated with brachytherapy (BT). We compared dosimetric outcomes of pulse-dose-rate (PDR) and high-dose-rate (HDR)-BT, according to linear-quadratic model.Methods and MaterialsThree-dimensional dosimetric data of 10 consecutive patients with cervical cancer undergoing intracavitary image-guided adaptive PDR-BT after external beam radiation therapy were examined. A new HDR plan was generated for each patient using the same method as for the PDR plan. The procedure was intended to achieve the same D₉₀ high-risk clinical target volume with HDR as with PDR planning after conversion into dose equivalent per 2 Gy fractions (EQD2) following linear-quadratic model. Plans were compared for dosimetric variables.ResultsAs per study's methodology, the D₉₀ high-risk clinical target volume was strictly identical between PDR and HDR plans: 91.0 Gy (interquartile: 86.0–94.6 Gy). The median D₉₈ intermediate-risk clinical target volume was 62.9 Gy_EQD2 with HDR vs. 65.0 Gy_EQD2 with PDR (p < 0.001). The median bladder D_2cc was 65.6 Gy_EQD2 with HDR, vs. 62 Gy_EQD2 with PDR (p = 0.004). Doses to the rectum, sigmoid, and small bowel were higher with HDR plans with a median D_2cc of 55.6 Gy_EQD2 (vs. 55.1 Gy_EQD2, p = 0.027), 67.2 Gy_EQD2 (vs. S 64.7 Gy_EQD2, p = 0.002), and 69.4 Gy_EQD2 (vs. 66.8 Gy_EQD2, p = 0.014), respectively. For organs at risk (OARs), the effect of radiobiological weighting depended on the dose delivered. When OARs BT contribution to D_2cc doses was <20 Gy_EQD2, both BT modalities were equivalent. OARs EQD2 doses were all higher with HDR when BT contribution to D_2cc was ≥20 Gy_EQD2.ConclusionBoth BT modalities provided satisfactory target volume coverage with a slightly higher value with the HDR technique for OARs D2_cc while intermediate-risk clinical target volume received higher dose in the PDR plan. The radiobiological benefit of PDR over HDR was predominant when BT contribution dose to OARs was >20 Gy.     

Impact of dosimetric parameters on local control for patients treated with three-dimensional pulsed dose-rate brachytherapy for cervical cancer

PurposeTo investigate the impact of dose-volume histograms parameters on local control of three-dimensional (3D) image-based pulsed dose-rate brachytherapy (BT).Methods and MaterialsWithin a French multicentric prospective study, the data of the 110 patients treated for cervical cancer with external beam radiotherapy followed by 3D image-based and optimized pulsed dose-rate BT were analyzed. Delineation procedures were performed on magnetic resonance imaging in a minority of cases and on CT for the majority of cases, adapted from the Gynaecological Groupe Européen de Curiethérapie—European Society for Therapeutic Radiology and Oncology recommendations. Optimization procedure was left to the discretion of the treating center.ResultsAt 2 years, local control rate reached 78%. Dose to Point A, total reference air kerma, and intermediate-risk clinical target volume (IR-CTV) V₆₀ were predictive factors for local control (p = 0.001, p = 0.001, and p = 0.013, respectively). Patients with IR-CTV V₆₀ <75% had a relative risk of local recurrence of 3.8 (95% confidence interval, 1.4–11.1). There was no correlation found between the high-risk clinical target volume dosimetric parameters and local control.ConclusionsThis multicentric study has shown that 3D image-based BT provides a high local control rate for cervical cancer patients. The V₆₀ for IR-CTV was identified as an important predictive factor for local control.     

422例宫颈癌患者调强放疗加后装治疗的不良反应和预后因素分析

目的 观察宫颈癌患者调强放疗+后装治疗±化疗的不良反应和疗效,分析其预后影响因素。方法 回顾性分析徐州医科大学附属江阴临床学院、南京医科大学附属常州市第二人民医院和苏州大学附属第一医院收治的422例接受调强放疗+后装治疗±化疗的宫颈癌患者的临床资料和随访结果,其中同期放化疗353例,单纯放疗69例。Kaplan-Meier法计算总生存（OS）率,Logrank法行预后单因素分析和Cox法行预后多因素分析。结果 同期放化疗与单纯放疗完全缓解（CR）率分别为77.6%和65.2%,两组差异有统计学意义（χ²=4.812,P<0.05）。全组患者1、3和5年OS率分别为93.4%、79.4%和65.0%。年龄、国际妇产科联盟（FIGO）2009分期、淋巴结转移状况、病理类型、放疗同期的化疗情况、近期疗效和序贯化疗情况是影响预后的因素（χ²=6.375~613.123,P<0.05）。多因素分析显示,FIGO分期、淋巴结转移状况、病理类型、放疗同期的化疗情况和近期疗效是影响患者预后的独立因素（χ²=3.930~42.994,P<0.05）。盆腔淋巴结阳性患者行或未行预防性腹主动脉旁淋巴结（PALN）引流区放疗后PALN转移率分别为6.1%和16.8%,差异无统计学意义（P>0.05）;预防性PALN引流区放疗患者的OS高于未行预防性放疗患者（χ²=3.953,P<0.05）。结论 宫颈癌患者采用调强放疗+后装治疗±化疗的治疗模式可取得较好的长期生存。盆腔淋巴结转移患者行预防性PALN引流区放疗有助于改善OS。FIGO分期、病理类型、淋巴结转移状况、是否同期放化疗以及近期疗效是影响患者预后的独立因素。     

The equivalent dose contribution from high-dose-rate brachytherapy to positive pelvic lymph nodes in locally advanced cervical cancer

PurposeDefinitive radiation therapy for locally advanced cervical cancer involves external beam radiation therapy (EBRT) and high-dose-rate (HDR) brachytherapy. There remains controversy and practice pattern variation regarding the optimal radiation dose to metastatic pelvic lymph nodes (LNs). This study investigates the contribution of the pelvic LN dose from HDR brachytherapy.Methods and MaterialsFor 17 patients with 36 positive pelvic LNs, each LN was contoured on a computed tomography (CT) plan for EBRT and on brachytherapy planning CTs using positron emission tomographic images obtained before chemoradiation. The mean delivered dose from each plan was recorded, and an equivalent dose in 2-Gy fractions (EQD2) was calculated. A Student's t test was performed to determine if the mean delivered dose is significantly different from the mean prescribed dose and EQD2.ResultsThe average prescribed dose from the total EBRT was 54.09 Gy. The average prescribed HDR dose to International Commission on Radiation Units point A was 26.81 Gy. The average doses delivered to the involved LNs from EBRT and brachytherapy were 54.25 and 4.31 Gy, respectively, with the corresponding EQD2 of 53.45 and 4.00 Gy. There was no statistically significant difference (p < 0.05) between the mean delivered and the prescribed doses for EBRT and between the delivered dose and the EQD2 for EBRT and brachytherapy.ConclusionsOur study shows that the HDR contribution is 7% (4.00 Gy) of the total EQD2 (57.45 Gy). The HDR contribution should be accounted for when prescribing the EBRT boost dose to pelvic LNs for the optimal therapeutic dose.     

Early outcomes and impact of a hybrid IC/IS applicator for a new MRI-based cervical brachytherapy program

PurposeThe purpose of this study was to report early outcomes and assess the learning curve in a new MRI-based cervical brachytherapy program.MethodsWe accrued 33 patients prospectively, and only patients with ≥3 months' followup (n = 27) were assessed for disease control and toxicity. Eras were defined as first half and second half for the intracavitary (IC)-only era (n = 13 each), and the intracavitary/interstitial (IC/IS) era was separated by difference in applicator availability (n = 7). Dose to 90% of the high-risk clinical target volume (D₉₀ HR-CTV) and minimum dose to the maximally irradiated 2 cubic centimeters (D_2cc) to organs at risk were used to assess dosimetry. Statistics were performed with t tests and Kaplan–Meier method.ResultsMedian followup was 14.7 months. Median treatment duration was 50.5 vs. 57 days for patients treated with external beam radiation therapy at our institution vs. an outside institution (p = 0.03). One-year local control, noncervical pelvic control, distant metastasis–free rate, and overall survival were 84.0%, 96.0%, 78.5%, and 91.3%, respectively. When comparing the first half and second half eras of IC only, there were no differences in median D₉₀ HR-CTV or D_2cc of the bladder, rectum, or sigmoid. Comparing the entire IC era to the IC/IS era, median D₉₀ HR-CTV trended higher from 88.0 Gy to 92.9 Gy (p = 0.11). D_2cc rectum decreased from 69.3 Gy to 62.6 Gy (p = 0.01), and D_2cc bladder trended lower from 87.5 Gy to 83.6 Gy (p = 0.09).ConclusionsThere was no significant difference between the first half and second half eras with IC-only MRI-based brachytherapy. Incorporation of an IC/IS applicator generated the greatest dosimetric improvement. Early results of the MRI-based brachytherapy program are favorable.     

宫颈癌二维近距离后装治疗中危及器官参考点剂量与三维体积剂量的相关性研究

目的 利用宫颈癌二维近距离后装治疗中危及器官（OARs）点剂量预测其三维体积剂量,评估在特定条件下,二维计划OARs体积剂量能否满足三维后装剂量限值要求。方法 回顾性分析基于CT图像的10例宫颈癌患者近距离后装治疗计划,将处方参考点剂量定为600 cGy,膀胱和直肠参考点剂量<360 cGy,设计并优化得到二维后装治疗计划。采用Pearson相关分析法对膀胱、直肠参考点剂量及OARs体积受量做相关性分析,利用线性回归方法得出膀胱、直肠参考点与其体积剂量的线性方程。结果 膀胱、直肠参考点剂量分别与其D_{1 cm³}、D_{2 cm³}、D_{5 cm³}和平均剂量显著正相关（r=0.559~0.668,P<0.05）;膀胱、直肠参考点剂量分别是其D_{2 cm³}的1.404和1.181倍;内外照射完成后膀胱、直肠D_{2 cm³}的相当于200 cGy分次等效生物剂量（EQD2）分别为8 410.0和6 827.0 cGy,均低于二者体积剂量限值。结论 利用膀胱、直肠参考点剂量能在一定程度上预测其体积剂量,对于满足膀胱、直肠参考点剂量低于处方剂量60%二维近距离后装计划,可将膀胱、直肠体积受量控制在相对安全的剂量范围内。而由于缺乏对小肠、乙状结肠剂量检测,二维后装计划在临床使用上仍然具有很大局限性。