Evaluation of Rectal Dose During High-Dose-Rate Intracavitary Brachytherapy for Cervical Carcinoma

High-dose-rate intracavitary brachytherapy (HDR-ICBT) for carcinoma of the uterine cervix often results in high doses being delivered to surrounding organs at risk (OARs) such as the rectum and bladder. Therefore, it is important to accurately determine and closely monitor the dose delivered to these OARs. In this study, we measured the dose delivered to the rectum by intracavitary applications and compared this measured dose to the International Commission on Radiation Units and Measurements rectal reference point dose calculated by the treatment planning system (TPS). To measure the dose, we inserted a miniature (0.1 cm³) ionization chamber into the rectum of 86 patients undergoing radiation therapy for cervical carcinoma. The response of the miniature chamber modified by 3 thin lead marker rings for identification purposes during imaging was also characterized. The difference between the TPS-calculated maximum dose and the measured dose was <5% in 52 patients, 5–10% in 26 patients, and 10–14% in 8 patients. The TPS-calculated maximum dose was typically higher than the measured dose. Our study indicates that it is possible to measure the rectal dose for cervical carcinoma patients undergoing HDR-ICBT. We also conclude that the dose delivered to the rectum can be reasonably predicted by the TPS-calculated dose.     

Variability of Marker-Based Rectal Dose Evaluation in HDR Cervical Brachytherapy

In film-based intracavitary brachytherapy for cervical cancer, position of the rectal markers may not accurately represent the anterior rectal wall. This study was aimed at analyzing the variability of rectal dose estimation as a result of interfractional variation of marker placement. A cohort of five patients treated with multiple-fraction tandem and ovoid high-dose-rate (HDR) brachytherapy was studied. The cervical os point and the orientation of the applicators were matched among all fractional plans for each patient. Rectal points obtained from all fractions were then input into each clinical treated plan. New fractional rectal doses were obtained and a new cumulative rectal dose for each patient was calculated. The maximum interfractional variation of distances between rectal dose points and the closest source positions was 1.1 cm. The corresponding maximum variability of fractional rectal dose was 65.5%. The percentage difference in cumulative rectal dose estimation for each patient was 5.4%, 19.6%, 34.6%, 23.4%, and 13.9%, respectively. In conclusion, care should be taken when using rectal markers as reference points for estimating rectal dose in HDR cervical brachytherapy. The best estimate of true rectal dose for each fraction should be determined by the most anterior point among all fractions.     

Novel Use of the Contura for High Dose Rate Cranial Brachytherapy

A popular choice for treatment of recurrent gliomas was cranial brachytherapy using the GliaSite Radiation Therapy System. However, this device was taken off the market in late 2008, thus leaving a treatment void. This case study presents our experience treating a cranial lesion for the first time using a Contura multilumen, high-dose-rate (HDR) brachytherapy balloon applicator. The patient was a 47-year-old male who was diagnosed with a recurrent right frontal anaplastic oligodendroglioma. Previous radiosurgery made him a good candidate for brachytherapy. An intracavitary HDR balloon brachytherapy device (Contura) was placed in the resection cavity and treated with a single fraction of 20 Gy. The implant, treatment, and removal of the device were all completed without incident. Dosimetry of the device was excellent because the dose conformed very well to the target. V90, V100, V150, and V200 were 98.9%, 95.7%, 27.2, and 8.8 cc, respectively. This patient was treated successfully using the Contura multilumen balloon. Contura was originally designed for deployment in a postlumpectomy breast for treatment by accelerated partial breast irradiation. Being an intracavitary balloon device, its similarity to the GliaSite system makes it a viable replacement candidate. Multiple lumens in the device also make it possible to shape the dose delivered to the target, something not possible before with the GliaSite applicator.     

Radiation Dose in the Uterine Perforation by Tandem in 3-Dimensional Cervical Cancer Brachytherapy

Cervical cancer patients may sometimes experience different types of uterine perforation by a tandem during brachytherapy. The purpose of this study was to address possibly different management strategies regarding different tandem positions from a dosimetry aspect by evaluating radiation doses delivered to organs-at-risk (OAR) in order to help medical professionals handle different types of uterine perforation. Images and dosimetry data in cervical cancer brachytherapy with uterine perforation were reviewed. Uterine perforation was classified into anterior and posterior perforation according to their tandem positions. Radiation doses received by OAR, including D_2cc and D_1cc of the bladder, rectum, and sigmoid colon, were statistically compared with nonperforation. The doses of high-risk clinical target volume (HR-CTV) of cervical tumor and bilateral point A were also compared in order to assure that the plans had not compromised the treatment efficacy. A total of 21 applications were assessed, including 5 with anterior perforation, 4 with posterior perforation, and 12 without perforation. In anterior perforation, the bladder was the only organ that received a significantly increased dose about 30% at D_2cc and D_1cc. However, in posterior perforation, multiple OAR received significantly excessive doses: approximately 30% for the bladder, 37% for the rectum, and 100% for the sigmoid colon. The OAR dose assessment was based on a statistically equivalent cervical tumor dose. Different management strategies are possible for anterior vs posterior perforation during brachytherapy due to different detrimental extents on OAR dosimetry. The bladder warrants more attention in anterior perforation, without compromising target coverage in treatment planning. On the other hand, repositioning may be considered in posterior perforation due to relatively massive OAR detriments. This concept is a new one and is given for the first time.     

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.     

Dosimetric study of CO-60 source step size in uterine cervix intracavitary HDR brachytherapy

Purpose

The present work reports effects of source step sizes on dose distribution in patients treated with cobalt-60 (Co-60) high-dose-rate afterloading brachytherapy in carcinoma cervix (Ca-cx).

Optimization of high-dose-rate cervix brachytherapy applicator placement: the benefits of intraoperative ultrasound guidance

PURPOSE: To promote efficient workflow for image-guided high-dose-rate (HDR) brachytherapy (BT) for cervix cancer by implementing intraoperative ultrasound (US) guidance for placement and optimization of intrauterine applicators. We sought to establish this as part of routine radiation oncology practice without radiology consultation. METHODS AND MATERIALS: Thirty-five consecutive insertions were performed in 21 women between July 2006 and March 2007. Cervical dilation, tandem selection and insertion were guided by transabdominal US. Final tandem position following vaginal applicator insertion was also confirmed by US. Computed tomography (CT) imaging was used for treatment planning and to assess perforation and applicator suitability for each patient anatomy. RESULTS: Intrauterine tandem insertion was successfully guided by US in the majority of procedures (34/35). CT imaging confirmed accurate placement within the uterine canal in each case, compared with a historic institutional perforation rate of 10%. Visualizing patient anatomy during insertion altered the selection of tandem length and angle in 49% of cases, resulting in improved applicator matching to anatomy. Average insertion time significantly decreased from 34 to 26 minutes (p=0.01). Requests for assistance from gynecologic surgical oncology declined from 38% to 5.7% of procedures. CONCLUSIONS: Intraoperative US guidance for cervix BT has been successfully implemented with staff and equipment from radiation oncology. Using US during every insertion has led to improved applicator selection and placement while decreasing procedure time and reducing out of department consultations. These changes have eliminated repeat insertions due to unfavorable applicator placement (as revealed on postoperative CT), thus improving department efficiency and quality of patient care.     

The American Brachytherapy Society prostate brachytherapy LDR/HDR simulation workshops: Hands-on,step-by-step training in the process of quality assurance

PurposeEducation and training on prostate brachytherapy for radiation oncology and medical physics residents in the United States is inadequate, resulting in fewer competent radiation oncology personnel to perform implants, and is a factor in the subsequent decline of an important, potentially curative cancer treatment modality for patients with cancer. The American Brachytherapy Society (ABS) leadership has recognized the need to establish a sustainable medical simulation low-dose-rate (LDR) and high-dose-rate (HDR) brachytherapy workshop program that includes physician–physicist teams to rapidly translate knowledge to establish high-quality brachytherapy programs.MethodsThe ABS, in partnership with industry and academia, has held three radiation oncology team–based LDR/HDR workshops composed of physician–physicist teams in Chicago in 2017, in Houston in 2018, and in Denver in 2019. The predefined key metric of success is the number of attendees who returned to their respective institutions and were actively performing brachytherapy within 6 months of the prostate brachytherapy workshop.ResultsOf the 111 physician/physicist teams participating in the Chicago, Houston, and Denver prostate brachytherapy workshops, 87 (78%) were actively performing prostate brachytherapy (51 [59%] HDR and 65 [75%] LDR).ConclusionsThe ABS prostate brachytherapy LDR/HDR simulation workshop has provided a successful education and training structure for medical simulation of the critical procedural steps in quality assurance to shorten the learning curve for delivering consistently high-quality brachytherapy implants for patients with prostate cancer. An ABS initiative, intended to bend the negative slope of the brachytherapy curve, is currently underway to train 300 new competent brachytherapy teams over the next 10 years.     

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.     

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.     

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.     

A modified technique for high-dose-rate intracavitary brachytherapy in advanced cancer of the cervix

PURPOSE: To develop a modified technique for high-dose-rate intracavitary brachytherapy in cervical cancer stage IIIb. METHODS AND MATERIALS: Cervical carcinoma FIGO Stage III accounts for > 60% of all cervical cancers with radiation being the mainstay of treatment for most patients. After external beam radiation therapy (EBRT), the cervix is often flush with the vagina and the shape of the vagina may be conical with its apex at the external os level. All patients receive 2 applications with HDR brachytherapy. At the first application after the placement of the central tandem, only one ovoid is inserted and the other ovoid is replaced by a rubber tube, and the applicator assembly is fixed as usual. The contralateral ovoid is inserted at the subsequent application. RESULTS: To date, 21 locally advanced cervical cancer patients have been treated using this technique. In these patients, the mean dose to right and left Point A was 93% (range, 86-100%; median, 93%) and 95% (range, 90-100%; median, 95%), respectively. The variation of doses to the contralateral Point A was 1-14%. The mean dose to the rectal and bladder mucosa was 62% (range, 43-80%; median, 64%) and 80% (range, 50-110%; median, 71%), respectively. CONCLUSION: This modified HDR intracavitary technique may prove an alternative for centers where interstitial brachytherapy for cancer of the cervix is not available.     

支气管动脉灌注与高剂量率支气管腔内放疗联合治疗非小细胞肺癌(附27例报道)

目的: 探讨支气管动脉灌注化疗(BAI) 与高剂量率支气管腔内后装放射治疗( HDRIBB) 两项新技术联合治疗非小细胞肺癌的可行性、方法学和临床价值。材料与方法: 对27 例非小细胞肺癌采用BAI 与铱192高剂量率支气管腔内后装放射治疗两项新技术进行序贯或交替方式的联合治疗,观察主、客观近期疗效、毒副反应与并发症。结果: 24 例有临床症状的患者,71 % (17/24) 得到不同程度的改善;27 例中92 .6 % (25/27) 的患者KPS 评分提高或稳定。近期客观缓解率:CR 8 例,PR 15 例,有效率(CR+ PR) 为85 % ;病理组织学疗效:显效2 例,有效5 例,部分有效2 例。结论: 支气管动脉灌注化疗与铱192 高剂量率支气管腔内后装放射治疗联合治疗非小细胞肺癌为有效方案,有较好的近期主、客观疗效,对中央型和周围型肺癌均适用。联合治疗安全可行,毒副反应及并发症轻微。联合治疗用于早期不能耐受手术的非小细胞肺癌的根治性治疗和综合治疗后局部残存或复发的治疗具有较大的临床研究价值     

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。     

Evaluating the impact of real-time multicriteria optimizers integrated with interactive plan navigation tools for HDR brachytherapy

PurposeCurrently in high-dose-rate (HDR) brachytherapy planning, manual fine-tuning of an objective function is a common practice. Furthermore, automated planning approaches such as multicriteria optimization (MCO) are still limited to the automatic generation of a single treatment plan. This study aims to quantify planning efficiency gains when using a graphics processing unit–based MCO (gMCO) algorithm combined with a novel graphical user interface (gMCO-GUI) that integrates efficient automated and interactive plan navigation tools.Methods and MaterialsThe gMCO algorithm was used to generate 1000 Pareto optimal plans per case for 379 prostate cases. gMCO-GUI was developed to allow plan navigation through all plans. gMCO-GUI integrates interactive parameter selection tools directly with the optimization algorithm to allow plan navigation. The quality of each plan was evaluated based on the Radiation Treatment Oncology Group 0924 protocol and a more stringent institutional protocol (INSTp). gMCO-GUI allows real-time time display of the dose–volume histogram indices, the dose–volume histogram curves, and the isodose lines during the plan navigation.ResultsOver the 379 cases, the fraction of Radiation Treatment Oncology Group 0924 protocol valid plans with target coverage greater than 95% was 90.8%, compared with 66.0% for clinical plans. The fraction of INSTp valid plans with target coverage greater than 95% was 81.8%, compared with 62.3% for clinical plans. The average time to compute 1000 deliverable plans with gMCO was 12.5 s, including the full computation of the 3D dose distributions.ConclusionsCombining the gMCO algorithm with automated and interactive plan navigation tools resulted in simultaneous gains in both plan quality and planning efficiency.     

Clinical feasibility of MR-assisted CT-based cervical brachytherapy using MR-to-CT deformable image registration

PurposeThe purpose of this study is to evaluate the feasibility of using deformable image registration algorithms to improve high-dose-rate high-risk clinical target volume (HR-CTV) delineation between preapplicator implantation MRI (pre-MRI) and postapplicator implantation CT (post-CT) in the treatment of locally advanced cervical cancer (LACC).Method and materialsTwenty-six patients were identified for the study. Regions of interest were segmented on MRI and CT. A HR-CTV was delineated on pre-MRI and compared with the previously contoured HR-CTV on the post-CT. Two commercially available algorithms, ANACONDA (anatomically constrained) and MORFEUS (biomechanical model based) with various controlling structure settings, including the cervix, uterus, etc., were used to deform pre-MRI to post-CT. MRI-to-CT deformed targets are denoted as HR-CTV’. Quantitative deformation metrics include Dice index, distance to agreement, and center of mass displacement. Qualitative clinical usefulness of deformations was scored based on HR-CTV identification on CT images.ResultsFor ANACONDA and MORFEUS deformations, using a cervix controlling region of interest resulted in the highest Dice, lowest distance to agreement, and lowest center of mass displacement for HR-CTV′. With MORFEUS deformations, the deformed HR-CTV’ proved clinically useful in 23 patients.ConclusionsPrebrachytherapy implantation MRI can aid target contours for CT-based brachytherapy through ANACONDA or MORFEUS algorithms with appropriate parameter selection for LACC patients.     

Intracavitary brachytherapy for carcinoma of the uterine cervix--comparison of HDR (Ir-192) and MDR (Cs-137)

Purpose To compare the results of high dose rate (HDR) (Ir-192) and medium dose rate (MDR) (Cs-137) intracavitary brachytherapy (ICRT) for carcinoma of the uterine cervix. Materials and Methods Between May 1991 and March 2001, a total of 206 patients with Stage I-IVA previously untreated cervical cancer were treated with ICRT combined with external beam radiotherapy (EBRT). HDR was administered to a total of 135 patients: 22 patients in Stage I, 49 in Stage II, 56 in Stage III, and eight in Stage IVA. MDR was administered to a total of 71 patients: six patients in Stage I, 27 in Stage II, 33 in Stage III, and five in Stage IVA. The MDR at point A was 30 Gy/hour for HDR and 1.7 Gy/hour for MDR treatment, and the corresponding median follow-up periods for survivors were 55 and 68 months. Results For the HDR group, 5-year cause-specific survival rates were 90%, 78%, 53% and 33% for Stages I, II, III, and IVA, respectively. For the MDR group, the corresponding rates were 100%, 76%, 51%, and 40%. In the HDR group, 19 patients (14%) developed Grade 2 or higher late complications, and, in the MDR group, four patients (6%) did. Conclusions There was no statistically significant difference in cause-specific survivals between the results of HDR and MDR brachytherapy for cervical cancer. The incidence of late complications tended to be higher for the HDR group than for the MDR group, but did not show a statistically significant difference (p=0.07).     

Template-based high-dose-rate interstitial brachytherapy in gynecologic cancers: A single institutional experience

PurposeTo report the outcome and toxicities of radical external beam radiotherapy (EBRT) and template-based high-dose-rate interstitial brachytherapy (ISBT) in patients diagnosed with cervical cancer undergoing inadvertent surgery, vault cancers, and vaginal cancers at our institution.Methods and MaterialsBetween January 2000 and December 2008, 113 patients (37 patients of cervical cancer post-inadvertent surgery, 57 patients with vault cancers, and 19 patients with primary vaginal cancers) were treated with Martinez Universal Perineal Interstitial Template brachytherapy boost after EBRT. The median EBRT dose was 50 Gy, median ISBT dose was 20 Gy, whereas median total dose was 73 Gy equivalent dose at 2 Gy per fraction in all three groups.ResultsMedian followup of surviving patients for the whole group was 43 months (interquartile range, 19–67 months). The 3-year actuarial disease-free survival and overall survival for three groups was 61%, 61%, 59% and 64%, 64%, and 56%, respectively. Grade III/IV rectal toxicity was seen in 11 (10%) patients, bladder toxicity in 5 (4.5%) patients, whereas 7 (6%) patients developed Grade III small bowel toxicity. Residual disease at brachytherapy had significant impact on DFS and OS. Other factors such as age, disease volume, parametrial extension, and vaginal extension did not impact the survivals.ConclusionsMartinez Universal Perineal Interstitial Template–based high-dose-rate ISBT boost in gynecologic cancer results in a reasonable outcome in terms of survivals with acceptable late toxicities. The use of template-based ISBT is associated with a definite learning curve.