Brachytherapy Fractions Research Articles

Quality of life and Comprehensive Geriatric Assessment (CGA) in older adults receiving Accelerated Partial Breast Irradiation (APBI) using a single fraction of Multi-Catheter Interstitial High-Dose Rate Brachytherapy (MIB). The SiFEBI phase I/II trial

ObjectivesThe SiFEBI trial demonstrated that a post-operative Multicatheter Interstitial Brachytherapy (MIB) appears feasible and with acceptable toxicity in older adults aged 70 years and older presenting with low-risk breast cancer. The aim of the present ancillary study was to analyze the quality of life and Comprehensive Geriatric Assessment (CGA) domains within 6 months in older adults receiving Accelerated Partial Breast Irradiation (APBI) using a single fraction of MIB. Materials and MethodsFrom 11/2012 to 09/2014, 37 patients were included and 26 were evaluable. Patients (pts) aged 70 years and older with a Balducci score of 1 or 2 and presenting with low-risk breast cancer were prospectively enrolled in this phase I/II trial (NCT01727011). After lumpectomy, intra-operative catheter implantation was performed for post-operative APBI after pathological findings. Quality of life (QoL) evaluation and CGA were scheduled at baseline and 1, 3, and 6 months after APBI. Autonomy decline was defined as a 1-point decrease in Activities of Daily Living (ADL). ResultsMean age was 77 years. Within the first 6 months of follow-up, no autonomy decline was observed in ADL, 3 patients had an autonomy decline in Instrumental Activities of Daily Living (IADL) and 2 patients had a slower gait speed but no changes in cognitive function, nutritional status, and depression screening. Global QoL was quite similar at baseline compared to 1, 3, and 6 months. No differences were observed for functional items. ConclusionAPBI based on a single fraction of MIB in older adults with low-risk breast cancer appears to be feasible with a minimal loss of autonomy regarding IADL, no loss of autonomy in ADL, an acceptable decrease in other CGA domains, and with no impact on global quality of life.

00003 Volumetric assessment of cervical cancer tumor volume during definitive chemoradiation and the risk of early distant metastasis

ABSTRACT IMPACT: This study assesses patient and volumetric risk factors for distant recurrence within 6 months of completion of curative chemoradiation with brachytherapy in locally advanced cervical cancer. OBJECTIVES/GOALS: Initial tumor volume and tumor shrinkage velocity are prognostic of cure and survival after curative chemoradiation (CRT) for cervical cancer. We explored whether local tumor volumetric changes influence time to distant recurrences outside the radiation field. METHODS/STUDY POPULATION: We performed a retrospective cohort study of patients with FIGO Stage IB-IVA cervical cancer treated with curative CRT and brachytherapy at a tertiary academic center with minimum 3 months follow up and standard post-treatment FDG-PET. Patients received 6 weekly fractions of brachytherapy interdigitated with external beam radiation and cisplatin. Tumor volumes were assessed by MRI at brachytherapy planning. Patients who developed distant metastasis were classified as earliest (3-6 months), early (6-24 months) or late (>24 months) following completion of CRT. Absolute and percent decrease in tumor volume for each fraction were calculated with respect to first brachytherapy volume. Fisher’s exact and Mann Whitney-U tests were used for comparison of categorical and continuous variables. RESULTS/ANTICIPATED RESULTS: 143 of 574 (25%) patients developed distant metastasis. Distribution of age, histology, FIGO 2018 stage, primary tumor SUVmax, treatment length, and pre/post treatment squamous cell carcinoma antigen levels were not associated in each group. Para-aortic lymph metastases were more common in patients with earliest distant recurrence (33% earliest, 26% early, 12% late, p=0.03). Median initial tumor volume in the earliest (n=24), early (n =29) and late (n=9) groups was 57, 28 and 40 mL, respectively (p=0.08); 57 (earliest) vs 30mL (early+late groups), p=0.04. Average mid treatment (fraction 4) and end of treatment (fraction 6) percent shrinkage was 80 (earliest) vs 73 (early+late), p=0.84 and 94 vs 92, p=0.95, respectively. Neither absolute nor percent tumor shrinkage differed between early vs. late groups. DISCUSSION/SIGNIFICANCE OF FINDINGS: Tumor volumetric changes during definitive chemoradiation were not associated with the timing of developing distant metastasis, which is linked to presence of lymph node metastasis and tumor volume at diagnosis.

Comparison of clinical outcomes achieved with image-guided adaptive brachytherapy for cervix cancer using CT or transabdominal ultrasound

PurposeThis study aimed to evaluate retrospectively the treatment results when using various image-guided adaptive brachytherapy treatments for cervical cancer treated by radical radiotherapy. Methods and MaterialsFrom 2014 to 2017, 188 patients with cervical carcinoma were treated by whole pelvic radiotherapy plus four fractions of image-guided brachytherapy. Eight patients were excluded because of missing data. Consequently, 180 patients were analyzed. Of 180 patients, 92 were treated by CT-based brachytherapy (CT-BT), and transabdominal ultrasound–based brachytherapy (TAUS-BT) was used to treat another group. The treatment results and toxicity outcomes were evaluated by comparing the image-guidance techniques. ResultsThe mean follow-up time was 32 months (interquartile range 29.5–42 months). The mean age was 57 years (interquartile range from 50 to 65 years). In the CT-BT group, the mean cumulative doses to high-risk clinical target volume, bladder, rectum, and sigmoid were 87.2 Gy, 84.0 Gy, 68.8 Gy, and 69.8 Gy, respectively. In the TAUS-BT group, the mean cumulative doses to the cervix reference, bladder, and rectum points were 84.0 Gy, 65.5 Gy, and 74.0 Gy, respectively. There were no differences in the 2-year local control rate (p = 0.88) and disease-free survival rate (p = 0.34) in both groups. No difference in gastrointestinal and genitourinary toxicity was observed in both groups, but there was higher vaginal toxicity in the TAUS-BT group compared with the CT-BT group (p = 0.03). ConclusionsNo difference in treatment results was observed between CT-based and TAUS-based approaches. However, TAUS-BT had higher vaginal toxicity in our retrospective analysis.

Effects of brachytherapy on cytogenetic parameters and oxidative status in peripheral blood lymphocytes of gynecologic cancer patients.

The state-of-the-art brachytherapy technologies with high-dose sources of 60Co and 192Ir within contemporary treatment protocols for cancer patients allow achieving maximum dose distribution in the clinical target and with minimum radiation exposure of surrounding organs and tissues. For minimization and overcoming the early and late radiation complications, development of respective radiobiological criteria along with perfecting of physical and technical characteristics of the ionizing radiation sources are required. To study the effect of 192Ir radiation on the chromosomal aberrations and prooxidant/antioxidant status of blood lymphocytes in gynecological cancer patients. The patients (n= 45) with endometrial, cervical and secondary cancer of vagina were enrolled in the study. For brachytherapy, the irradiation of vaginal mucosa was conducted using "GammaMed plus" device for contact radiation therapy with 192Ir source. Prior to irradiation and in 20-24h after brachytherapy session, the venous blood samples were obtained and peripheral blood lymphocytes (PBL) were cultured for cytogenetic analysis. The prooxidant/antioxidant status was determined in hemolysates by the method of hydrogen peroxide-induced chemiluminescence. The average level of spontaneous chromosome aberrations in PBL of the patients was (7.8± 0.4) per 100metaphases, which is more than twice higher than the upper limit of the average population values. The frequency of chromosome aberrations in PBL of patients after brachytherapy session was (15.3± 1.0) per 100metaphases. An increased intensity of O2- generation by PBL after brachytherapy session was also noticed. Local irradiation at a dose of 6Gy featuring the first dose fraction of brachytherapy induces extra chromosomal aberrations in PBL of gynecological cancer patients and intensifies prooxidant processes in the blood.

Study of Two Fractions versus Three Fractions of High Dose Rate Brachytherapy in Locally Advanced Carcinoma of Uterine Cervix after Pelvic Concurrent Chemoradiotherapy

Study of Two Fractions versus Three Fractions of High Dose Rate Brachytherapy in Locally Advanced Carcinoma of Uterine Cervix after Pelvic Concurrent Chemoradiotherapy

Dosimetric changes and interfraction anatomical variations during high dose rate brachytherapy of cervical cancers- Can replanning be avoided?

Interfraction variations occur due to tumour regression during cervical intarcavitary brachytherapy (ICR) requiring replanning with every fraction. This study aimed to determine the correlation of interfraction variations in positioning of applicator and its relationship with relative dosimetry if the dwell time and source positions of the plan of first fraction were applied to other subsequent fractions.This is a retrospective review of the orthogonal radiographs of cervical cancer patients treated from 2013 to 2016 in our institute, receiving ICR with the same dose prescription to point A using a tandem and two ovoids applicators. A hypothetical second and third plan were obtained by applying the same source positions and dwell time as in the first fraction plan. The dose delivered to point A, point B, cervical point, bladder point and rectal point were determined. The actual doses in the treated second and third fractions were compared with these hypothetical plans for any significant change in relative dosimetry. Statistical differences between groups were analysed using 2 tailed paired t test. There was consistant increase in the doses to the point B, bladder point and rectal point in all the hypothetical plans with statistically significant difference observed for point B (p=0.001), rectal point (p=0.000) and bladder point(p=0.041).The conception of avoiding the replanning if similar interfraction conditions are achieved looks promising but the significant findings observed in this study warrants strongly to continue as per current recommendation of replanning with every fraction of brachytherapy.

Looking Beyond D90: A Novel Way of Correlating Brachytherapy Quality With Local Control in Cervix Cancer

The current formalism for reporting and adding the effects of BT and external beam (EB) RT doses are based on a single metric, D90 to HR-CTV and its EQD2. Previously published work however, has demonstrated that BED(D90) is unable to distinguish between plans that are optimized differently or created with different applicator systems. In comparison, EUBED and gBEUD, which both integrate voxel level BED, are better at discerning these important differences. We sought to measure local control in women being treated with radiotherapy for locally advanced cervix cancer and assess its correlation with EUBED and gBEUD over the whole volume of HR-CTV compared to the traditional, single point metrics D90. 163 women with FIGO 2018 IB3-IIIC2 cervical cancer from 3 institutions were included. All women received EBRT ± chemotherapy and 3-5 fractions of intracavitary brachytherapy. The median follow-up for all women was 59.5 months (range 0-87 months). At this time 6.1% have had local recurrences, 12.2% distant recurrences, 1.2% both local and distant. Data was extracted from TPS and dosimetric and radiobiological quantities computed. EUBED and gBEUD were calculated for each fraction. EUBED uses an extra parameter α (range 0.05-0.5Gy-1) with smaller values typically associated with radioresistant tumors. Similarly, gBEUD uses a parameter a which allows a variable emphasis on hot/cold spots (range –5,5). Distributions were compared using the 2-sample Kolmogorov-Smirnoff test at 5% significance. Distributions of all dosimetric quantities were compared among institutions, starting with CTV size and D90. D90 did not distinguish between patient populations with different outcomes. EUBED integrates biological effect over a volume in a manner very similar with gBEUD for negative a. Such exponents are typically used in relation with local control emphasizing ‘cold spots.’ Interestingly, a large ‘hot’ volume is present in all T&O and T&R applications and some practitioners even emphasize contiguity of 150% or 200% isodoses in their plans. gBEUD for positive values [3.5] proved to be the only metric that successfully predicted local recurrence. Based on these findings, gBEUD should be included routinely to the set of parameters used to evaluate implants. This is particularly important now, when based on increased use of MRI and of hybrid devices one has the ability to create dose distributions which are significant departures from the classical pear.Tabled 1Abstract 3063; TableInstitutionABCHR-CTV Volume (cm3)41.6±15.031.9±14.936.2±21.0D90 (%PD)101.5±11.7112.5±24.3117.2±10.5 Open table in a new tab

Preliminary Results Of MR-Guided Brachytherapy Boost To External Beam Radiotherapy For Intermediate And High Risk Prostate Cancer

To determine if the superior soft tissue differentiation on magnetic resonance imaging (MRI)-guided high dose rate (HDR) brachytherapy (BT) planning increases the therapeutic index of BT boost intensification strategies for localized prostate cancer (PCa), we report the early results of a prospective study of HDR BT boost using a MRI only workflow. Eligible patients (pts) included intermediate- (IR) and high-risk (HR) PCa. Treatment consisted of whole gland boost with HDR BT (15Gy single, or 10Gy two fractions), using MRI alone for BT needle insertion and treatment planning (technical details previously described). Where applicable, the second fraction was usually delivered during week 3 or 4 of external beam radiotherapy (EBRT). EBRT to prostate +/- pelvic nodes, as clinically indicated, commenced within 1 week following BT. EBRT was planned using intensity modulated radiotherapy. Pts also received androgen deprivation therapy (ADT) as per their risk status. Follow-up assessments included CTCAE (v4)-graded toxicity, EPIC questionnaire, and PSA at baseline, 1, 3, 6, 12, 24, 36, and 60 months. Between 2010 and 2018, 120 pts were enrolled and had >6-month follow-up. Median age of pts was 69.5 years (47 – 78 years); 53 (44 %) pts had IR, and 67 (56 %) pts had HR PCa. The median baseline PSA was 12.3 ng/ml (3.2 – 148 ng/ml). Overall, 87 (73%) pts had ADT of whom 56 (64%) had HR disease. Median duration of ADT was 2 years. A total of 144 BT fractions were completed with 22 (18%) pts receiving 2 x 10Gy and 97 (81%) pts received 1 x 15Gy. 43% of pts received subsequent EBRT 37.5Gy/15# to prostate alone. 57% of pts received pelvic and prostate EBRT with majority receiving 46Gy/23# (40 – 60Gy). The median PTV V100 was 95% (91.5 – 99.1%). Median urethra D0.5cc, rectum D0.5cc and bladder D0.5cc were 122% (106 – 166%), 83% (62 – 93%) and 90% (63 – 124%). After a median follow-up of 36 months (6 – 109 months), the overall 3-year biochemical recurrence (Phoenix definition) free rate was similar between IR and HR pts at 94%. At last follow up, 1 patient had seminal vesicle recurrence, 6 (5%) had developed metastatic disease confirmed radiologically. EPIC GU, GI, and sexual domain scores showed mean declines from baseline at 1-month post treatment and then gradual recovery. GU scores returned toward baseline levels by 24 months, GI by 36 months. Sexual domain demonstrated minimal recovery by 36 months follow up. Late CTCAE grade 2/3 GU, GI and sexual toxicities occurred in 22%, 6%, and 5% of pts, respectively. There were 6 (5%) CTCAE grade 3 adverse events, 3 sexual and 3 GU, but no grade 4 toxicity. Early results of MR-guided BT boost in PCa is associated with acceptable biochemical control, toxicity and quality of life. Late grade ≥2 toxicities were comparable to other studies and GU/GI quality of life returned to baseline by 3 years. Further follow up will determine long-term outcomes.

Acute Toxicity and Local Response using Three Fractions of High Dose Rate (HDR) Brachytherapy for Curative Treatment of Carcinoma Cervix.

Descriptive study. Radiation Oncology Section, Department of Oncology, The Aga Khan University Hospital, Karachi, Pakistan from January 2008 till December 2015. Protocol was formulated for carcinoma cervix to complete treatment in 7 weeks. Patients were treated with chemotherapy and pelvic EBRT to a total dose of 45 Gy/25 fractions, followed by three intracavitary HDR brachytherapy fractions of 8 Gy each. Vaginal toxicity and local clinical response was assessed at the end of treatment, at 4 and 8 weeks. A total of 57 patients were treated with HDR brachytherapy and 49 patients were evaluated for assessment of toxicity and response. According to FIGO staging system, two had stage IB2, one had IIA, thirty-six had IIB, seven had IIIB, one had IVA disease and two had IVB with para aortic nodes. Concurrent gemcitabine and cisplatin were given to 26 (46%); whereas, 28 (49%) received concurrent cisplatin alone. Grade III acute vaginal mucosal toxicity was seen in 52 and Grade IV acute vaginal mucosal toxicity was observed in 08 patients. At completion of treatment, 40 patients had complete clinical response, at 4 weeks follow-up, complete regression of disease was found in 3 more and at 8 weeks none had clinical residual disease. This regimen of HDR brachytherapy treatments is feasible, efficacious, and well-tolerated for carcinoma cervix in a setup with cost constraints. Long term toxicity and disease control remains to be reported with longer follow-up. Key Words: Carcinoma cervix, High dose rate brachytherapy, Acute toxicity, Local response, External beam radiation therapy, Intracavitary brachytherapy.

A knowledge-based organ dose prediction tool for brachytherapy treatment planning of patients with cervical cancer

PurposeThe purpose of this study is to explore knowledge-based organ-at-risk dose estimation for intracavitary brachytherapy planning for cervical cancer. Using established external-beam knowledge-based dose-volume histogram (DVH) estimation methods, we sought to predict bladder, rectum, and sigmoid D2cc for tandem and ovoid treatments. Methods and materialsA total of 136 patients with loco-regionally advanced cervical cancer treated with 456 (356:100 training:validation ratio) CT-based tandem and ovoid brachytherapy fractions were analyzed. Single fraction prescription doses were 5.5–8 Gy with dose criteria for the high-risk clinical target volume, bladder, rectum, and sigmoid. DVH estimations were obtained by subdividing training set organs-at-risk into high-risk clinical target volume boundary distance subvolumes and computing cohort-averaged differential DVHs. Full DVH estimation was then performed on the training and validation sets. Model performance was quantified by ΔD2cc = D2cc(actual)-D2cc(predicted) (mean and standard deviation). ΔD2cc between training and validation sets were compared with a Student's t test (p < 0.01 significant). Categorical variables (physician, fraction-number, total fractions, and case complexity) that might explain model variance were examined using an analysis of variance test (Bonferroni-corrected p < 0.01 threshold). ResultsTraining set deviations were bladder ΔD2cc = −0.04 ± 0.61 Gy, rectum ΔD2cc = 0.02 ± 0.57 Gy, and sigmoid ΔD2cc = −0.05 ± 0.52 Gy. Model predictions on validation set did not statistically differ: bladder ΔD2cc = −0.02 ± 0.46 Gy (p = 0.80), rectum ΔD2cc = −0.007 ± 0.47 Gy (p = 0.53), and sigmoid ΔD2cc = −0.07 ± 0.47 Gy (p = 0.70). The only significant categorical variable was the attending physician for bladder and rectum ΔD2cc. ConclusionA simple boundary distance-driven knowledge-based DVH estimation exhibited promising results in predicting critical brachytherapy dose metrics. Future work will examine the utility of these predictions for quality control and automated brachytherapy planning.

Changes in the cervical microbiota of cervical cancer patients after primary radio-chemotherapy

ObjectiveSeveral recent studies have identified a potential interaction between the vaginal microbiota and gynecological cancers, but little is known about the cervical microbiota and its changes during cancer treatment. Therefore,...

COVID-19 impact on timing of brachytherapy treatment and strategies for risk mitigation

PurposeThe purpose of this study was to highlight the importance of timely brachytherapy treatment for patients with gynecologic, breast, and prostate malignancies, and provide a framework for brachytherapy clinical practice and management in response to the COVID-19 pandemic. Methods and MaterialsWe review amassing evidence to help guide the management and timing of brachytherapy for gynecologic, breast, and prostate cancers. Where concrete data could not be found, peer-reviewed expert opinion is provided. ResultsThere may be a significant negative impact on oncologic outcomes for patients with gynecologic malignancies who have a delay in the timely completion of therapy. Delay of prostate or breast cancer treatment may also impact oncologic outcomes. If a treatment delay is expected, endocrine therapy may be an appropriate temporizing measure before delivery of radiation therapy. The use of shorter brachytherapy fractionation schedules will help minimize patient exposure and conserve resources. ConclusionsBrachytherapy remains a critical treatment for patients and may shorten treatment time and exposure for some. Reduced patient exposure and resource utilization is important during COVID-19. Every effort should be made to ensure timely brachytherapy delivery for patients with gynecologic malignancies, and endocrine therapy may help temporize treatment delays for breast and prostate cancer patients. Physicians should continue to follow developing institutional, state, and federal guidelines/recommendations as challenges in delivering care during COVID-19 will continue to evolve.

Fast and fully-automated multi-criterial treatment planning for adaptive HDR brachytherapy for locally advanced cervical cancer

PurposeTo develop and evaluate a fast, automated multi-criterial treatment planning approach for adaptive high-dose-rate (HDR) intracavitary + interstitial brachytherapy (BT) for locally advanced cervical cancer. Methods and materialsTwenty-two previously delivered single fraction MRI-based HDR treatment plans (SFclin) were used to guide training of our in-house system for multi-criterial autoplanning, aiming for an autoplan quality superior to the training plans, while respecting the clinically desired “pear-shaped” dose distribution. Next, the configured algorithm was used to automatically generate treatment plans for 63 other fractions (SFauto). The SFauto plans were compared to the corresponding SFclin plans in blind pairwise comparisons by an expert clinician. Then, the effect of adaptive autoplanning on total treatment (TT) plans (external beam + 3 BT fractions) was evaluated for 16 patients by simulating the clinically applied adaptive strategy to generate TTauto plans and compare them with the corresponding clinical treatments (TTclin). ResultsIn the blind comparisons, all SFauto plans were considered clinically acceptable. In 62/63 comparisons, SFauto plans were considered at least as good as, or better than the corresponding SFclin. The average optimization time for autoplanning was 20.5 ± 19.2 s (range 4.4–106.4 s) per plan. In 14 of 16 TTauto plans, the desired total dose of 90 Gy (EQD2) was obtained, compared to only 9 in the corresponding TTclin, while autoplanning also decreased bladder and rectum doses. ConclusionsFast, fully-automated multi-criterial treatment planning for adaptive HDR-BT for locally advanced cervical cancer is feasible. Autoplans were superior to corresponding clinical plans.

Implementation of peer-review quality rounds for gynecologic brachytherapy in a high-volume academic center

PurposeWhile peer review is critical for quality and safety in radiotherapy, there are neither formal guidelines nor format examples for brachytherapy (BT) peer review. We report on a gynecologic BT peer-review method implemented at a high-volume academic center. Methods and MaterialsWe analyzed discussions at bimonthly gynecologic BT peer-review rounds between July and December 2018. Rounds consisted of 2–5 attending physicians with gynecologic BT expertise, 1–2 BT physicists, and trainees. Peer-review targets included clinical case review, contours, implant technique, dose/fractionation, and target/organ-at-risk (OAR) dosimetry. The projected/final target and OAR dosimetry were analyzed. Results55 separate implants from 44 patients were reviewed. Implants were mostly reviewed after the first BT fraction (n = 16, 29%) or at another time point during BT (n = 20, 36%). One (2%) implant was presented prospectively. The applicator type and BT technique were reviewed for all implants. Dose/fractionation was evaluated for 46 implants (84%); contours were discussed for 21 (38%). Target and OAR dosimetry were reviewed for 54 (98%) and 28 implants (51%), respectively. Six cases (11%) underwent minor changes to the applicator type to improve target and/or OAR dosimetry. One case (2%) had a major change recommended to the dose/fractionation. ConclusionsGynecologic BT peer review may enhance BT quality by allowing for implant optimization and formal review of challenging cases, ultimately improving medical decision-making and team communication. Peer review should be implemented in centers offering gynecologic BT.

Predictive value of Excel forms based on an automatic calculation of dose equivalent in 2 Gy per fraction in adaptive brachytherapy for cervical cancer.

PurposeExternal beam radiotherapy (EBRT) combined with brachytherapy (BT) is the standard mode of radical radiotherapy for locally advanced cervical cancer. The cumulative equivalent doses in 2 Gy per fraction (EQD2) is an important basis for estimating the probability of local control of tumors and monitoring the occurrence of side effects in normal tissues. The purpose of this study was to explore the predictive value of Excel forms based on an automatic calculation in radical adaptive BT for cervical cancer.Material and methodsA retrospective analysis of 119 patients suffering from cervical cancer, treated with radical radiotherapy. All patients were treated with EBRT and adaptive BT. EBRT prescribed dose was 42.0-50.4 Gy in 21-28 fractions. BT nominal prescribed dose was 28 Gy in 4 fractions, separated by one week. Total EQD2 prediction at nth (n = 1-3) BT (TEPBn) or actual cumulative EQD2 (ACEQD2) can be calculated automatically by inputting the physical dose based on an in-house designed application. The relationship between TEPBn and ACEQD2 was evaluated, and the predictive value of Excel forms based on the automatic calculation was analyzed.ResultsFor the volume of high-risk clinical target, there was a significant decrease between BT1 and BT2. Similarly, for the volume of intermediate-risk clinical target, there was a significant decrease between BT2 and BT3. The sensitivity ranges of TEPB1, TEPB2, and TEPB3 prediction were 74.5-91.3%, 83.7-95.7%, and 92.9-99.1%, respectively, and the specificity ranges were 46.7-80.0%, 53.3-90.5%, and 66.7-90.5%, respectively.ConclusionsThe in-house designed application has the function of quickly reading dose-volume histogram (DVH) parameters from the treatment planning system, which allows for balance between the total dose to target volumes and organs at risk (OARs). Excel forms based on EQD2 automatic calculation presents high predictive accuracy.

Comparison of initial computed tomography-based target delineation and subsequent magnetic resonance imaging-based target delineation for cervical cancer brachytherapy.

PurposeFor cervical brachytherapy planning, magnetic resonance imaging (MRI) is preferable to computed tomography (CT) for target delineation. However, due to logistical and financial restrictions, in-room MRI is sometimes not routinely available in brachytherapy centers. Our institution has created a workflow that integrates MRI-based target delineation with an in-room CT scanner, with the aim of improving target coverage and conformality. This study reports the initial dosimetric results with using this workflow.Material and methodsA retrospective review was performed on 46 consecutive patients who received definitive chemoradiation with 5 fraction intracavitary high-dose-rate (HDR) brachytherapy for cervical cancer. Fraction 1 was planned from CT only. Outpatient MRI was obtained after Smit sleeve placement and first insertion to assess concurrent chemoradiotherapy tumor response. This MRI was registered to the CT for planning fractions 2-5. The median prescription dose for the cohort was 25 Gy (range, 25-29 Gy).ResultsThe D90 to the high-risk clinical target volume (HR-CTV) and D2cc rectal dose were increased from fraction 1 to fraction 2-5 averaged (p < 0.05). Among the 18 patients with complete volumetric data, there was no significant difference in HR-CTV size, with an average decrease of 1.73 cc (p > 0.05) with MRI fusion. Eleven out of 18 patients had changes in high-risk target volume greater than 20%, with an absolute average change in volume of 31.5%.ConclusionsThe use of asynchronous MRI for target delineation, with co-registration to CT for each fraction of brachytherapy was associated with higher D90 to the HR-CTV. We observed slightly higher D2cc rectal doses with MRI, but cumulative rectal doses were within accepted thresholds. High-risk target volumes were not consistently increased or decreased, but MRI fusion was associated with target volume changes greater than 20% in over half of the treated patients.

Combined external pelvic chemoradiotherapy and image-guided adaptive brachytherapy in treatment of advanced cervical carcinoma: experience from a single institution.

PurposeExternal pelvic chemoradiotherapy and image-guided adaptive brachytherapy (IGABT) were studied in advanced cervical carcinomas. Treatment modalities were defined and related to outcomes and side effects.Material and methodsFrom a single cancer center, 138 patients with advanced cervical cancer were recruited. All patients were treated with external radiotherapy and IGABT. A dosimetric study was performed and related to treatment outcome and side effects. Toxicity of the organs at risk was evaluated by the CTCAE-grading system.ResultsThe median follow-up was 44 months. More than 60% of the tumors were FIGO stage IIB-IIIB and 82% were squamous cell carcinomas. Largest tumor size (width) was in mean 41 mm and 27% had lymph node spread. The mean total external dose was 51 Gy, and the mean total dose to the high-risk clinical target volume (HRCTV) was 88 Gy. In 130 patients (94%), weekly cisplatin was given in 4-6 cycles. The median number of brachytherapy fractions was four, and in 86 patients, interstitial needles were applied. The primary local control was 97% and 94% after four local recurrences. The overall pelvic control was 89%. The overall recurrence rate was 25% and distant metastases rate was 22%. The overall 5-year survival rate was 65% and cancer-specific survival rate was 69%. Prognostic factors were FIGO stage and total brachytherapy dose (D90) to HRCTV. Late serious toxicity of the bladder and intestine were rare, occurring in only 3% of patients.ConclusionsThe local and pelvic control rates were excellent in this series. The IGABT was an important part of the treatment schedule and could probably not be replaced by increasing the external pelvic dose. Adenocarcinomas seemed to benefit from the addition of interstitial needles. Late serious toxicity was rare.

Time-driven activity-based costing of adjuvant vaginal cuff brachytherapy for uterine cancer in an integrated brachytherapy suite

PurposeAdjuvant vaginal cuff brachytherapy is well tolerated and reduces the risk of local recurrence in endometrial cancer. However, there is provider variation in the number of radiation treatments, which ranges from three to six fractions. Using time-driven activity-based costing, we calculated the cost to deliver three vs six fractions to determine the value of each regimen at our brachytherapy suite with CT-on-rails. Methods and MaterialsProcess maps were created to represent each step from initial consult to completion of therapy. Components of care included personnel, equipment, and consumable supplies. The capacity cost rate was determined for each resource and calculated for each regimen. ResultsThe total direct costs to deliver three- and six-fraction treatment courses were $1,415 and $2,227, respectively. Personnel cost accounted for 63% of overall expenditures. Computed tomography simulation and planning, required for the first fraction, cost $232 for both regimens. Duties of the procedural nurse (scheduling, patient setup, and turnover) consumed the most time at 35% of total personnel minutes. ConclusionsTime-driven activity-based cost analysis revealed a 57% relative increase, but modest absolute increase, in delivery costs for six vs three fractions of brachytherapy at our institution. This current analysis may influence considerations of the relative value between the two treatment schedules, but this methodology should not be interpreted as informative for reimbursement policy evaluation.

Is one brachytherapy fraction of 7Gy similar to more fractions after external beam irradiation in postoperative endometrial carcinoma?

To determine whether brachytherapy with a single hypofractionated dose of 7Gy provides the similar vaginal-cuff relapses and safety profile in terms of complications compared to schedules of 2 or 3 fractions of lower doses in patients treated previously with external beam irradiation in postoperative endometrial carcinoma. From June 2003 to December 2016, 325 patients were treated with 3 different schedules of high-dose-rate brachytherapy after external beam irradiation for postoperative endometrial carcinoma. The patients were divided into 3 groups: Group-1: 125 patients were treated with 3 fractions of 4-6Gy per fraction (3 fractions/week) between 2003 and 2008; Group-2: 93 patients were treated with 2 consecutive daily fractions of 5-6Gy between 2008 and 2011; Group-3: 107 patients received a single fraction of 7Gy between 2011 and 2016. Bladder and rectum complications were assessed using RTOG scores and with the objective scores of LENT-SOMA for the vagina. the chi-square test. The mean follow-up of Groups 1, 2 and 3 was 95, 67 and 51months, respectively. Three patients in Group-1, 2 in Group-2, 1 in Group-3 developed vaginal-cuff relapse (p = 0.68). No differences were found in late toxicity among the three groups. One single dose of 7Gy is safe and effective and may be the best treatment schedule with a similar incidence of vaginal-cuff relapses, complications and patient comfort with less hospital attendance.

Optimization of the accelerated partial breast brachytherapy fractionation considering radiation effect on planning target and organs at risk

The same fractionation scheme of accelerated partial breast irradiation (APBI) with brachytherapy is usually applied to APBI patients without considering the radiaton effect on the planning target and organs at risk (OARs) for an individual patient. The purpose of this study is to report the results of optimization of the fractionation scheme by evaluating the radiation effect on target and OARs with a modified linear-quadratic model, universal survival curve (USC), based on dose-volume histograms (DVHs). Ten breast patients treated with multilumen balloon brachytherapy were selected. The minimum skin and chest wall/rib (CW/rib) spacing ranged from 2.5 to 14.3 mm and from 0.5 to 25.0 mm, respectively. The USC model parameters were set as: (1) breast:α = 0.3, β = 0.05; (2) skin: acute reaction α = 0.101, β = 0.009; late reaction α = 0.064, β = 0.029; (3) CW/rib: α = 0.3, β = 0.12. Boundary dose Dt was 6 Gy for both target and OARs. The relation between radiation effects on the target (ET) and OARs (EOAR) were plotted for fraction numbers (N) from 1 to 20. If ET is set at a certain value, the fractionation that results in a minimum EOAR value corresponds to the optimal fractionation. The results show that the optimal fractionation is different for different OAR damage effects. For most of the patients, N = 2 is best for minimizing skin acute reactions while N = 20 is best for minimizing skin late reactions. N varies from 3 to 20 among patients for minimizing CW/rib toxicity. The determined unique optimal N for treatment delivery was found to vary from 1 to 20 among these 10 patients resulted from balancing the different damage effects considering the spatial dose for a given patient geometry. Optimal fractionation can be achieved for an individual patient by evaluating the radiation effect on tumor and OARs with the USC model based on the patient specific DVHs with APBI brachytherapy.