Intracavitary Brachytherapy For Cervical Cancer Research Articles

264 - Dosimetric difference of urinary bladder and rectum in patients undergoing intracavitary brachytherapy for cervical cancer under Sedation and General anesthesia. A Case at Bugando Cancer Center and Ocean Road Cancer Institute

264 - Dosimetric difference of urinary bladder and rectum in patients undergoing intracavitary brachytherapy for cervical cancer under Sedation and General anesthesia. A Case at Bugando Cancer Center and Ocean Road Cancer Institute

Effects of pain management using nonsteroidal anti-inflammatory drug suppositories during brachytherapy for cervical cancer: A single-center prospective observational study

IntroductionNo standardized pain management protocol exists for intracavitary brachytherapy, and various methods of analgesia have been used in different countries and institutions. This study aimed to investigate the effects of pain management during intracavitary brachytherapy using non-steroidal anti-inflammatory drugs (NSAIDs) or acetaminophen suppositories. MethodsIn this single-center, prospective, observational study, patients undergoing intracavitary brachytherapy for cervical cancer completed a questionnaire survey after each brachytherapy session, which comprised questions regarding pain intensity, satisfaction with analgesia, and desire for effective anesthesia. ResultsData analysis was performed using data from 100 brachytherapy sessions of 27 patients. The median numerical rating scale (NRS; 0–10) score for each intracavitary brachytherapy session was 3–4. The median satisfaction scale score for analgesia (5-point scale, 1–5) for each session was approximately 4. Eight patients (29.6%) answered that they desired anesthesia more effective than suppositories at any session of brachytherapy. A comparison of the high (NRS≥4) and low (NRS≤3) NRS groups during the first session revealed that the high NRS group tended to have higher NRS scores and lower satisfaction with analgesia during all sessions. A positive correlation was observed between tumor size and the NRS score during the first brachytherapy session. ConclusionsThe NRS score was approximately 3–4, and satisfaction with analgesia was approximately 4 out of 5 when NSAIDs or acetaminophen suppositories were used as analgesics during intracavitary brachytherapy for cervical cancer. Although the current pain management protocol is clinically acceptable, inadequate analgesia is indicated in approximately 30% of patients.

Low-dose-rate, high-dose-rate, and pulsed-dose-rate intra-cavitary brachytherapy for cervical cancer: The very first comparison study

Low-dose-rate, high-dose-rate, and pulsed-dose-rate intra-cavitary brachytherapy for cervical cancer: The very first comparison study

Development and validation of a novel scoring system to predict the risk of uterine perforation during intracavitary brachytherapy for cervical cancer.

To develop and validate a novel scoring system for predicting the risk of uterine perforation during brachytherapy (BT) in cervical cancer patients and to stratify patients based on this score to guide the use of ultrasound guidance during BT. Fifty patients with uterine perforation during BT between January 2018 and December 2020 were included. Common reasons for perforation were identified and a scoring system was developed. This was then applied to a cohort of 50 patients without perforation. The 2 cohorts were compared using the χ² test. To validate the scoring system, all newly diagnosed patients who underwent BT in 2021 were scored, and analysed using χ² test and receiver operator characteristic curves. The mean score in the test cohort was 10.16 (range=7-14) and 5.92 (range=5-8) for patients with and without perforation. In the validation cohort, the mean score was 6.9 (range=5-10) and 9.33 (range=7-11) for those with and without perforation. Patients with a score <8 were classified as low risk, while those with a score ≥8 were classified as high risk. Among the criteria evaluated for validation, response to external beam radiotherapy, uterine position, cervico-uterine angle (uterine flexion), identification of cervical os at BT assessment, and the total score were significant predictors, while previous history of perforation, uterine length, and additional uterine anomaly were not. The novel scoring system is an effective predictor of perforation risk during BT. Implementing this during BT assessment can optimize the need for ultrasound guidance during the procedure.

Impact of the COVID-19 Pandemic on Brachytherapy and Cancer Patient Outcomes: A Systematic Review

To assess the impact of the COVID-19 pandemic on the use of brachytherapy as a treatment modality in patients with gynecologic and prostate cancers including treatment delays, increased burden of mortality and associated clinical outcomes. A comprehensive search of PubMed, Cochrane Library, CINAHL, Scopus, and Web of Science was conducted using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Databases were searched for studies published through January 2023 using MeSH terms and keywords related to "COVID and brachytherapy". Inclusion criteria included all studies reporting on the impact of COVID-19 on treatment delay, treatment omission, recurrence rates and clinical outcomes in patients requiring brachytherapy for prostate or gynecologic cancers. Data were extracted from two pairs of independent reviewers. Of the 292 screened records, 8 retrospective studies met the eligibility criteria and were selected. A total of 15,879 patients were included, of which 829 brachytherapy patients were identified. An Italian study reported an increase in the use of adjuvant radiation therapy (RT) in patients with uterine cancers during the lockdown period while the use of vaginal cuff brachytherapy remained stable. Hypofractionated regimens were the preferred approach in RT centers worldwide. Intracavitary brachytherapy for cervical cancer was limited to 3-4 fractions to limit personnel and patient exposure. RT treatment delay was the most common COVID-related care change ranging between 19% and 53% followed by treatment omission (2-28%). Causes of treatment delays and omissions were multifactorial: patient fear, COVID-19 infection, barriers to accessing care and operating room closures. Two studies reported modified brachytherapy approaches using single-application (SA) rather than multiple applications (MA) approaches with excellent local control, shorter overall treatment time, but at the expense of increased grade ≥2 vaginal, genitourinary and gastrointestinal events. For cervical cancer patients, overall treatment time (OTT) was significantly impacted by COVID-19 as reported by 2 studies from India. OTT >60 days occurred in 40-53% of patients with COVID-19 infection being the main cause of treatment delays of up to 3 weeks. This is the first systematic review to assess the impact of the COVID-19 pandemic on brachytherapy in patients with gynecologic and prostate cancers. Although many expert consensus recommendations have been published during the pandemic regarding radiation therapy, few studies evaluated its clinical impact on brachytherapy delivery and patient outcomes. The impact of the pandemic on gynecologic and prostate cancers is yet to be determined as well as the long-term outcomes on patients treated during the lockdown period.

Prospective Dosimetric Comparison Study Between Volumetric Modulated Arc Therapy and Intracavitary Brachytherapy for Cervical Cancer

Although volumetric modulated arc therapy (VMAT) boost can achieve highly conformal dose distributions for cervical cancer, VMAT has the disadvantage of requiring set-up and organ motion margins. This study prospectively recruited patients with the cervical cancer and compared VMAT plan with intracavitary brachytherapy (ICBT) plan. All patients treated with ICBT for locally advanced cervical cancer between April 2020 and September 2022 were enrolled. Patients had whole-pelvis radiotherapy, followed by CT scans with and without the tandem and ovoid in the same session (for the planning of ICBT and VMAT, respectively). ICBT planning characterizes the high-risk clinical target volume (HR-CTV) as the target volume and the bladder, rectum, sigmoid colon and small bowel loop as the organ at risk (OAR). VMAT planning defines the HR-CTV + 3 mm as the target volume and bladder, rectum + 3 mm (planning organ at risk volume (PRV) rectum), sigmoid colon + 3 mm (PRV sigmoid) and bowel bag as the OAR to account for set-up and organ motion. ICBT and VMAT plans were optimized for maximal dose received by at least 90% (D90%) of the target volume without impairing the dose constraints for the OARs. The prescribed dose (PD) was 26 Gy in 4 fractions. The dose constraints were determined as 25.2 Gy for D2 ml in the bladder and 20 Gy for D2 ml in the other OARs. The D90% and D100% of the target volume and D2 ml of OARs were compared between 2 plans using paired two-tailed Student's t test. Seventeen patients were enrolled. Dose and volume parameters for the 2 plans are shown in Table 1. Of the 17 patients, D90% of the target volume received 100% PD in 4 cases with ICBT plans, in 6 cases for VMAT plans, and in 2 cases with both methods. For D90% of the target volume, ICBT plans were greater than VMAT plans in 4 cases, with a maximum difference of 5.6 Gy (ICBT: 26.0 Gy, SBRT: 20.4 Gy). VMAT plans were higher than ICBT plans in 11 cases, with a maximum difference of 10.3 Gy (ICBT: 14.5 Gy, SBRT: 24.8 Gy). The dose-limiting OARs to attain D90% of target volume were bladder in 12 cases and small bowel loop in 1 case for ICBT plans, while PRV rectum in 11 cases, PRV sigmoid in 4 cases and bowel bag in 1 case for VMAT plans. This prospective study with 17 ICBT-eligible patients revealed D90% of the target volume demonstrated no substantial difference between VMAT and ICBT plans, while D100% showed a significant increase in VMAT plan compared to ICBT plan. Even with a set-up and organ motion margins on the HR-CTV and OARs, VMAT may have a dosimetric advantage over ICBT if the target geometry is complicated and close to the OARs.

Feasibility of Using a Single Planning MRI for Two-Insertion Intracavitary Brachytherapy for Cervical Cancer

MRI is an essential tool in treatment planning for cervical cancer patients undergoing definitive chemoradiation involving brachytherapy. However, due access to MRI for many patients may be limited. We sought to examine the feasibility and quality of treatment planning for organs at risk (OAR) and target volumes of a single treatment planning MRI for a planned two-insertion HDR intracavitary cervical brachytherapy. Eighteen patients with cervical cancer who underwent MRI-based treatment planning for intracavitary brachytherapy were selected for analysis. Patients underwent two intracavitary applicator insertions using a tandem and ring applicator (TnR_1 and TnR_2) with both CT (for digitization only) and MRI following each insertion and two fractions delivered with each insertion (total 7 Gy x 4fx). MRI-based TnR_2 plans were retrospectively replanned with the following procedure: 1) register MRI from TnR_1 to TnR_2 CT, 2) transfer cervix contour (Cx_simul) and plan from TnR_1 to TnR_2 CT, simulating blinding from TnR_2 MRI, 3) crop Cx_simul from TnR_2 OARs, 4) adjust plan only to meet OAR constraints or clinical doses if clinical plan (TnR_2 original MRI plan summed with TnR_1 and EBRT doses) violates constraints. Coverage changes (∆_D90%) in actual MRI defined TnR_2 cervix (Cx_real) was compared to clinical plans and evaluated against our clinical target goal: >85 Gy EQD2 (EBRT+BT). Differences between Cx_simul and Cx_real contours were evaluated with Dice Similarity Coefficient (DSC). Changes in bladder, rectum, rectosigmoid, and bowel D2cc was evaluated. Procedure time was recorded to determine time added by MRI (time between CT and final MRI timestamps; n = 29). Plan modification to meet OAR constraints was required for 5/18 plans. Cx_real target coverage from clinical to simulated plans decreased in 7/18 plans (∆_D90% = 1.7±6%). Composite EQD2 was <85 Gy in 2/18 cases, with ∆_D90% of -1.3% (clinical EQD2<85 Gy for this case also) and -7.3%, which was due to inconsistent cervix shape between insertions 1 and 2. Cervix DSC values between Cx_simul and Cx_real ranged from 0.68-0.88 (mean = 0.78 ± 0.06). Bladder, rectum, rectosigmoid, and bowel D2cc increased on average 4 ± 12%, 3 ± 9%, 5 ± 10%, and 5 ± 17%, respectively. Including planning MRI increased procedure time by 41.8 ± 10.4 min. The proposed method of utilizing TnR_1 MRI contours for TnR_2 CT planning reduces procedure time and provides reasonable target coverage for most cases. OAR assessment varies between imaging modality which likely represents variability in OAR position rather than treatment planning modality. Next steps are to increase patients studied, and implement this technique prospectively while waiting for TnR_2 MRI completion and compare the clinical TnR_2 MRI plan with the TnR_2 CT plan created with Cx_simul. This will provide further confidence in validity of the approach and ensure plan quality is maintained prior to full implementation.

Dosimetric Difference of Urinary Bladder and Rectum in Patients Undergoing Intracavitary Brachytherapy for Cervical Cancer under Procedural Sedation and General Anesthesia: A Survey at Bugando Cancer Center and Ocean Road Cancer Institute

Background: High-Dose-Rate Intracavitary Brachytherapy (HDR-ICBT) is a commonly employed treatment modality for cervical cancer, delivering a high dose of radiation directly to the tumor site while minimizing exposure to surrounding healthy tissues. Anaesthesia administration during HDR-ICBT varies, with some centres using Sedation (CS) and others employing General Anaesthesia (GA). Despite the widespread use of these anaesthesia techniques, their potential impact on dosimetric outcomes, particularly in the urinary bladder and rectum, remains an area of interest and investigation. Objective: This study aimed to determine the dosimetric difference in the urinary bladder and rectum doses among cervical cancer patients undergoing HDR-ICBT under CS and GA. The study was conducted at Bugando Cancer Centre (BCC) and Ocean Road Cancer Institute (ORCI) to compare the dosimetric outcomes between the two anaesthesia techniques. Methods: A total of 273 patients who underwent HDR-ICBT for cervical cancer were included in the study. Patients were divided into two groups based on the anaesthesia technique used during the procedure: 143 patients received GA, and 130 patients received CS. Dosimetric parameters of the urinary bladder and rectum doses were collected and analysed using descriptive statistics and the independent samples t-test. Results: The findings demonstrated a statistically significant dosimetric difference in the mean urinary bladder dose between patients treated under GA and CS (p &lt; 0.001). Patients under GA received a significantly lower mean urinary bladder dose compared to those under CS. However, no statistically significant difference was observed in the mean rectum dose between the two anaesthesia groups (p = 0.689). Conclusion: The study reveals that the choice of anesthesia technique significantly impacts the urinary bladder dose during HDR-ICBT for cervical cancer. Patients receiving GA had a lower mean urinary bladder dose compared to those under CS. However, no significant dosimetric difference was observed in the mean rectum dose between the two anesthesia groups. These findings emphasize the importance of considering anesthesia techniques during treatment planning to optimize dosimetric outcomes and patient safety in HDR-ICBT. Further investigation and long-term follow-up are warranted to validate and expand upon these results. Collaboration between radiation oncologists and anesthesia teams is crucial to enhance treatment efficacy and minimize potential complications during HDR-ICBT for cervical cancer

Comparison of Dose-Volume Histograms in Intracavitary Brachytherapy of Cervical Cancer using Manual Plan and Inverse Optimization Technique

Comparison of Dose-Volume Histograms in Intracavitary Brachytherapy of Cervical Cancer using Manual Plan and Inverse Optimization Technique

Dosimetric comparison of rectal dose-reductive techniques in intra-cavitary brachytherapy for cervical cancer: A retrospective analysis.

Rectal complications in radiotherapy for cervical cancer can highly affect quality of life and correlate with rectal dose. Vaginal gauze packing (VP) and rectal retraction (RR) are widely used for rectal dose reduction in high-dose-rate brachytherapy. We aimed to perform a dosimetric comparison of these two methods for three-dimensional image-guided adaptive brachytherapy. We retrospectively examined 50 patients with cervical cancer treated with definitive radiotherapy, including intra-cavitary brachytherapy, performed with VP and RR. We extracted two fractions for each patient: one fraction with VP and the next fraction with RR, and then compared dose-volume parameters. In total, 50 fractions each were analyzed in VP and RR groups. Dose to 90% (D90) of high-risk clinical target volume (HR-CTV), and minimum dose to most exposed 2.0 cm3 of other organs at risk (D2cm3) for the rectum and bladder were determined from planning computed tomography. There were no significant differences between VP and RR in D90 of HR-CTV (mean: 7.479 Gy and 7.652 Gy, respectively, p = 0.172). The D2cm3 values for the rectum (mean: 4.234 Gy vs. 4.627 Gy, p = 0.008) and bladder (mean: 5.959 Gy vs. 6.690 Gy, p < 0.001) were significantly lower with VP compared with RR. VP reduced the dose to the rectum and bladder when compared with RR without impairing the dose to CTV.

Anesthesia for Intracavitary Brachytherapy: a 19-month Experience at the Philippine General Hospital during the COVID-19 Pandemic.

Brachytherapy is the only demonstrated technique of delivering the high radiation dose required to control cervical cancer (>80 Gray [Gy]) without causing unwanted side effects. There is still limited data available in the Philippines regarding the anesthetic management of patients receiving intracavitary brachytherapy for cervical cancer. It is the aim of this study to present the anesthetic management of these procedures performed in a non-operating site remote from the main hospital during the first 1 ½ years of the COVID-19 pandemic. A retrospective review of 446 eligible charts was made. Data collected included demographic variables, ASA physical status classification, anesthetic technique, anesthetic agents used, oxygen supplementation device, duration of procedure, intra-procedure complication, intra-procedure pain medications, post-procedure pain medications, recovery room (RR) rescue medications, time to fulfill discharge criteria, and patient disposition. Four hundred forty-six (446) anesthetic encounters involving 117 patients is presented. Charts from 46 patients were excluded as it cannot be located. Mean age of the patients was 49 years with majority having normal BMI. Spinal anesthesia (SA) was more frequently (75%) used compared to total intravenous anesthesia (TIVA). Less than 5% immediate anesthesia-related complications were recorded and all patients were discharged on the same day. Spinal anesthesia and TIVA are safe and effective anesthetic techniques in patients with cervical cancer undergoing high dose intracavitary brachytherapy. Prospective studies to assess other aspects of their care as well as anesthesia-related long-term effects from repetitive anesthetic exposure is recommended.

Comparison of dose volume histograms and international commission of radiation units and measurement point doses to bladder and rectum in carcinoma cervix patients treated with intracavitary brachytherapy in department of radiotherapy

International commission of radiation units and measurement point doses to the bladder and rectum in carcinoma cervix patients treated with intracavitary brachytherapy in the department of radiotherapy. The aim: to evaluate two-dimensional point-based dose planning and three-dimensional computed tomography-based dose-volume parameters for high-dose-rate intracavitary brachytherapy of cervical cancer. Materials and methods: prospective study done between the years June 2018 to April 2020, a total of 50 prospectively registered women of non-metastatic carcinoma cervix treated with definitive concurrent chemo-radiotherapy followed by HDR intracavitary brachytherapy who met inclusion criteria were accrued in the study. All women in the study were treated with 50 Gy EBRT then assessment was done for response and adequacy for comfortable insertion of application. Brachytherapy procedure was performed under sedation in the lithotomy position. Results: Median age of the entire group was 54.5 years, majority of them were in their 5th (34 %) or 4th (28 %) decade. Pathologically, all were squamous cell carcinoma. Most common subtype was large cell non keratinizing type (64 %). Major bulk of the study is contributed by stage IIA, IIB, IIIB. All patients were treated with external beam radiotherapy of 50Gy in 25 fractions with 2Gy per fraction followed by high dose rate brachytherapy of 7 Gy per fraction for 3 fractions, one week apart to a total intracavitary brachytherapy dose of 21Gy. Conclusion: Results from the study suggests that rectum ICRU reference points can be surrogate markers for D2cc, but not for bladder and hence reporting should preferably be done in volumetric method rather than reference point doses

Intracavitary brachytherapy with additional Heyman capsules in the treatment of cervical cancer

PurposeBrachytherapy is a mandatory component of primary radiochemotherapy in cervical cancer. The dose can be applied with a traditional intracavitary approach (IC alone) or with multiple catheter brachytherapy to optimize dose distribution in an individual concept. We therefore evaluated whether the utilization of a tandem–ring applicator plus additional intracavitary applicators (add IC) provides an advantage over the traditional IC alone approach, as this method is less time consuming and less invasive compared to a combined intracavitary/interstitial brachytherapy.MethodsTwenty three procedures of intracavitary brachytherapy for cervical cancer with additional intracavitary applicators performed in seven patients treated between 2016 and 2018 in our institution were included in this study. Plans were optimized for D90 HR-CTV with and without the utilization of the additional applicators and compared by statistical analysis.ResultsD90 for HR-CTV was 5.71 Gy (±1.17 Gy) for fractions optimized with add IC approach and 5.29 Gy (±1.24 Gy) for fractions without additional applicators (p < 0.01). This translates to a calculated mean EQD2 HR-CTV D90 of 80.72 Gy (±8.34 Gy) compared to 77.84 Gy (±8.49 Gy) after external beam therapy and four fractions of brachytherapy for add IC and IC alone, respectively (p < 0.01). The predictive value of improved coverage of HR-CTV in the first fraction was high.ConclusionIn a subgroup of cases, the addition of intracavitary Heyman capsules can be an alternative to interstitial brachytherapy to improve the plan quality compared to standard IC alone brachytherapy. The benefit from the addition of applicators in the first fraction is predictive for the following fractions.

Dose Variation To Critical Points In Low Dose Rate Intracavitary Brachytherapy Of Cervical Cancer As Justification For Incident Learning

Background: Low Dose Rate (LDR) brachytherapy necessitates a more extended treatment duration. This technique maintains the patient on the treatment machine for a longer length of time, which may cause changes in the applicators' position due to vaginal packing soaking and patient movement for incident learning justification.&#x0D; Objective: The purpose of this study is to evaluate pre- and post-dosage variation to points 'A' and 'B,' as well as vital organs (i.e. bladder and rectum), for low dose rate (LDR) brachytherapy at Komfo Anokye Teaching Hospital and justify the need for incident learning system.&#x0D; Method: Forty (40) patients with invasive cervical cancer were treated with LDR brachytherapy equipment (A Curietron Cesium Manuel (AMRA)-France, CA 98.22) to point 'A' at doses ranging from 30 to 35 Gy. Adult patients selected for the study ranged from 25 to 60 years simulated. For each patient, orthogonal images of anterior-posterior (AP) and (LAT) were taken by positioning the patient on the Varian Acuity Simulator Couch at 00 and 900, respectively, and two sets of orthogonal images (before and after treatment), in each case, were considered. The treatment was then planned using the AP and LAT images obtained based on the four arrangements used, namely 1-2-5, 1-3-5, 1-4-5, and 1-5. The treatment planning system used for the study was the Prowess Panther system 4.6.&#x0D; Results: The dosage disparity at point 'A' was determined to be 1.16 per cent, which is highly commendable compared to previous research that established dose variations of 2%, 35%, 8%, and 20%. In this study, the dosage variation at point B was 0.75 per cent. The bladder and rectum had average alterations of 2.32 per cent and 0.30 per cent, respectively.&#x0D; Conclusion: The difference observed between prescribed, and deposited dosage was 2.11 per cent for quality assurance and incident learning reasons. Unrealistic expectations, reliance on reminders and quick remedies, and faults in the systemic view of failure were discovered and addressed as managerial issues. It is critical not to underestimate these difficulties because they are frequently significantly more severe than the technical issues being addressed. Incident issues were not recorded per patients under review, but near misses and non-conformance were observed. The geometric variances between the Intracavitary Brachytherapy Treatment (ICBT) applicators and the essential organs change during the treatment process, resulting in dosage changes. Does variance is within the required standard limits; it can be stated that Komfo Anokye Teaching Hospital's practice satisfies the international standard and is an intrusion into the Directorate Incident Learning System.

Active small bowel sparing in intracavitary brachytherapy for cervical cancer.

To propose and evaluate an active method for sparing the small bowel in the treatment field of cervical cancer brachytherapy by prone position procedure. The prone position procedure consists of five steps: making bladder empty, prone-positioning a patient on belly board, making the small bowel move to abdomen, filling the bladder with Foley catheter and finally turning the patient into the supine position. The proposed method was applied for the treatment of seven cervical cancer patients. Its effectiveness was evaluated and a correlation between the patient characteristics and the volumetric dose reduction of small bowel was also investigated. Brachytherapy treatment plans were built before and after the proposed method, and their dose-volume histograms were compared for targets and organs-at-risk. In this comparison, all plans were normalized to satisfy the same D90% for high-risk clinical target volume. For the enrolled patients, the average dose of small bowel was significantly reduced from 75.2±4.9Gy before to 60.2±4.0Gy after the prone position procedure, while minor dosimetric changes were observed in rectum, sigmoid and bladder. The linear correlation to body mass index, thickness and width of abdominopelvic cavity and bladder volume were 76.2, 69.7, 28.8 and-36.3%, respectively. The application of prone position procedure could effectively lower the volumetric dose of the small bowel. The dose reduction in the small bowel had a strong correlation with the patient's obesity and abdominal thickness. This means the patients for whom the proposed method would be beneficial can be judiciously selected for safe brachytherapy.

Impact of different treatment plans on EQD2 for intracavitary brachytherapy of cervical cancer

BackgroundCancer is one of the leading causes of death worldwide. According to GLOBOCAN estimates, there were 341,831 deaths from cervical cancer in 185 countries in 2020. The aim of this study was to compare equieffective dose (EQD2) at 2 Gy per fraction by using dose volume histograms (DVHs) derived from external beam radiotherapy (EBRT) and high-dose rate brachytherapy (HDR-BRT) treatment plans used in cervical cancer radiotherapy.MethodsFifteen patients with stage IIB-IIIB cervical cancer were included in this retrospective study. Treatment with three-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT) was planned for all patients in 28 fractions, with a total of 50.4 Gy to be delivered to the whole pelvic region. After EBRT, manual optimization (MO) or inverse optimization (IO) HDR-BRT plans were created in 4 fractions with a total of 28 Gy. The plans obtained were grouped as IMRT + IO, IMRT + MO, 3DCRT + IO, and 3DCRT + MO by calculating EQD2s among these plans. D90, D95, and D98 values were compared in all plans for CTVHR total EQD2. In addition, EQD2 values ​for critical organs at risk (OARs) such as rectum, bladder, small intestine, and sigmoid were compared in all plans for volumes of 2 cm3, 1 cm3, and 0.1 cm3, respectively.ResultsThere was no significant difference between the treatment groups in terms of CTVHR D90 and CTVIR D90 values; However, CTVHR D95 (p = 0.000) and CTVHR D98 (p = 0.000) values ​were found to be better in IMRT + IO technique. The IMRT + IO technique provided better protection for 2 cm3, 1 cm3, and 0.1 cm3 volumes of OARs compared to other techniques.ConclusionsConsidering all parameters such as CTVHR, CTVIR, rectum, bladder, small intestine, and sigmoid, combination of IMRT + IO treatment option was found to be significantly superior in total EQD2 calculations compared to other plans.

Intra-fractional dosimetric analysis of image-guided intracavitary brachytherapy of cervical cancer

BackgroundTo assess the intra-fractional dosimetric variations of image-guided brachytherapy of cervical cancer.MethodsA total of 38 fractions (9 patients) undergoing brachytherapy for cervical cancer underwent a CT scanning for treatment planning (planning CT) and a Cone-beam CT (CBCT) scanning immediately prior to delivery (pre-delivery CBCT). The variations of volumes as well as the dosimetric impact from treatment planning to delivery (intra-application) were evaluated. The dose volume histogram parameters including volume, D90 of high-risk clinical target volume (HRCTV) and D2cc of organs at risk (OARs) were recorded.ResultsThe relative differences (mean ± 1SD) of the volume and D90 HRCTV across the two scans were − 2.0 ± 3.3% and − 1.2 ± 4.5%, respectively. The variations of D2cc for bladder, rectum, sigmoid and small intestine are − 0.6 ± 17.1%, 9.3 ± 14.6%, 7.2% ± 20.5% and 1.5 ± 12.6%, respectively. Most of them are statistically nonsignificant except the D2cc for rectum, which showed a significant increase (P = 0.001). Using 5% and 10% uncertainty of physical dose for HRCTV at a 6 Gy × 5 high-dose-rate schedule, the possibility of total equivalent doses in 2 Gy fractions (EQD2) lower than 85 Gy is close to 0% and 3%, respectively. Performing similar simulation at 15% and 20% uncertainty of a 4 Gy physical dose for OARs, the possibility of total EQD2 dose exceeding 75 Gy is about 70%. Less than 1% of the total EQD2 of OARs would exceed 80 Gy.ConclusionsAverage intra-fractional dosimetric variation of HRCTV was small in an interval of less than 1 h, and the possibility of total EQD2 exceeding 85 Gy is higher than 97%. The intra-fractional dosimetric variations of OARs might result in an overdose for OARs in a single fraction or the whole treatment. It is necessary to detect unfavorable anatomical changes by re-imaging and take interventions to minimize applied doses and reduce the risk of complications.

Doses to Organs at Risk Calculated Using Plato and Oncentra Softwares in Intracavitary Brachytherapy

This is a retrospective study, the organ doses to the bladder and rectum were compared between Nucletron PLATO V14.2.3 (BV) and newer version software Oncentra MasterPlan V4.3 (OMP) treatment planning systems (TPS). The treatment data of 32 intracavitary brachytherapy patients at Hospital Universiti Sains Malaysia from January 2010 to June 2015 were used. These data sets were used for catheter reconstruction for both PLATO and OMP TPS followed by independent verification using Excel. There is no significant difference in mean doses to organs at risk (OARs) that calculated by both TPS (p&gt;0.05). The mean percentage of doses calculated by PLATO TPS for bladder and rectum were 66.58 ± 27.42 % and 46.27 ± 14.47 % respectively. While the mean percentage of doses for bladder and rectum calculated by OMP TPS were 65.68 ± 24.24 % and 46.46 ± 16.66 respectively. The mean percentage difference in doses comparison between independent verification calculation and PLATO TPS was 1.96 ± 6.00% and then became 6.37 ± 5.17% when it was compared with OMP TPS. Overall, the dose calculation differences for both versions of TPS were within the range recommended by Nuclear Regulatory Commission (NRC). The dose calculations of the two treatment planning systems showed good agreement and both could be used in planning intracavitary brachytherapy for cervical cancer. Whereas Excel based independent verification suitable to be implemented as routine dose verification programme prior to treatment delivery.

Prevention of uterine perforation during intracavitary brachytherapy of cervical cancer

PurposeIntracavitary brachytherapy (ICBT) is a part of standard treatment for loco-regionally advanced cervical cancers. ICBT requires a tandem applicator insertion through cervical canal into uterine cavity. Accurate placement through cervical canal, which is distorted by cancer, is crucial to successful treatment. The objective of this study was to investigate actual complication rate of a Smit sleeve insertion performed by experienced gynecologists in a tertiary referral center.Material and methodsClinical data of 328 patients with cervical cancer treated using ICBT, between January 2013 and August 2019, were retrospectively evaluated. Predisposing factors that could have increased the risk of uterine perforation were recorded. Pre-operative ultrasound was carried out for visualization of uterine curvature and selection of an appropriate Smith sleeve length. All applications were performed by a gynecologic oncology fellow or an expert gynecologist.Results317 patients were suitable for analysis. Only one (0.3%) applicator placement resulted in uterine perforation. In two patients, Smit sleeve dislocated after first brachytherapy and reinserted. Adequate applicator placement was achieved, and treatment was completed as planned in 316 cases.ConclusionsA cervical sleeve technic, which reduced the need for multiple insertions and placement of this instrument by an expert gynecologist minimize the risk of complication relative to historical controls.

Intraoperative ultrasound guidance during intra-cavitary brachytherapy of cervical cancer

Intraoperative ultrasound guidance during intra-cavitary brachytherapy of cervical cancer