Brachytherapy in the treatment of cervical cancer: a review

Monocentric Retrospective Study: Efficacy, Feasibility, and Prognostic Factors of Single-Insertion High-Dose-Rate Brachytherapy With 4 Sessions for Locally Advanced Cervical Cancer

Purpose

This study aims to assess the feasibility and efficacy of high-dose rate (HDR) brachytherapy (BT) administered in a single insertion with 4 treatment sessions for locally advanced cervical cancer and to identify the prognostic factors influencing outcomes.

Methods and Materials

We retrospectively analyzed the clinical data of patients with cervical cancer with locally advanced disease (International Federation of Gynecology and Obstetrics 2018 IB-IVB) treated at our institution from January 2014 through December 2021. Each patient received definitive radiation therapy with an external irradiation dosage between 45 and 50.4 Gy along with concurrent chemotherapy. HDR-BT (24 Gy) was prescribed to a high-risk clinical target volume.

Results

One hundred thirty-nine patients were included and the HDR-BT program could be fully performed in 136 patients (98%). Over a median follow-up duration of 40.5 months, the 2-year local control (LC), overall survival (OS), and disease-free survival rates stood at 79.4%, 77.7%, and 61.7%, respectively, with 5-year rates at 78.2%, 61.6%, and 55.7%. Multivariate analysis revealed the primary determinant of LC as the tumor's response to external beam radiation therapy as determined via magnetic resonance imaging before BT. Parametrial involvement demonstrated a significant multivariate association with disease-free survival (P = .04). Regarding OS, parametrial invasion (P = .01) and the tumor's response postchemoradiotherapy (P = .02) emerged as significant factors. Regarding chronic toxicities, 18% (25 patients) experienced grade 3 complications. An optimal D2 cc (bowel) threshold of 70 Gy (P = .001) was identified to limit chronic digestive complications of grade 3 or higher.

Conclusions

The implementation of single-insertion, 4-session HDR-BT could be performed in 98% of the patients. It yields favorable LC and OS rates, coupled with tolerable toxicity in patients with locally advanced cervical cancer. Response to initial chemoradiotherapy evaluated on pre-BT magnetic resonance imaging is an important prognostic factor and could help to individualize therapeutic strategies.

Integration of Ultrasound in Image-Guided Adaptive Brachytherapy in Cancer of the Uterine Cervix

Cervical cancer continues to be a public health concern, as it remains the second most common cancer despite screening programs. It is the third most common cause of cancer-related death for women, and the majority of cases happen in developing nations. The standard treatment for locally advanced cervical cancer involves the use of external beam radiation therapy, along with concurrent chemotherapy, followed by an image-guided adaptive brachytherapy (IGABT) boost. The five-year relative survival rate for European women diagnosed with cervical cancer was 62% between 2000 and 2007. Updated cervical cancer treatment guidelines based on IGABT have been developed by the Gynecological working group, which is composed of the Group Européen de Curiethérapie-European Society for Therapeutic Radiology and Oncology. The therapeutic strategy makes use of three-dimensional imaging, which can be tailored to the target volume and at-risk organs through the use of computed tomography or magnetic resonance imaging. Under anaesthesia, the brachytherapy implantation is carried out. Ultrasonography is utilised to assess the depth of the uterine cavity and to facilitate the dilation of the uterine canal during the application insertion. In this study, we examine data from the international literature regarding the application of ultrasound in cervical cancer brachytherapy.

Radiochemotherapy and interstitial brachytherapy for cervical cancer: clinical results and patient-reported outcome measures

OBJECTIVE

To evaluate clinical results and long-term patient-reported outcome measures (PROMs) on quality of life in cervical cancer patients following radiochemotherapy (RCT) and brachytherapy (BT) as definitive treatment.

MATERIALS AND METHODS

Between 2003 and 2023, a total of 132 patients with advanced cervical cancer were evaluated for possible treatment. Patients treated by postoperative RCT, palliative radiotherapy, and those treated for recurrent disease were excluded. Thus, 46 patients receiving standard RCT and BT as their curative treatment were included in this study. PROMs were assessed prospectively by patients' self-completion of the EORTC-QLQ-C30 and EORTC-QLQ-CX24 questionnaires.

RESULTS

Five-year overall survival (OS), distant metastases-free survival (DMFS), and pelvic tumor-free survival rates (PTFS) were 53%, 54%, and 83%, respectively. A significant impact on OS was seen for FIGO (International Federation of Gynecologic Oncology) stage (IIB-IIIA: 79% vs. IIIB-IVA: 33%, p = 0.015), for overall treatment time (OTT; 50-65 d: 64% vs. > 65 d: 38%, p = 0.004), and for rectal D2cc (≤ 73 Gy: 50% vs. > 73 Gy: 38%, p = 0.046). The identical parameters were significantly associated with DMFS (FIGO stage: p = 0.012, OTT: p = 0.008, D2cc: p = 0.024). No parameters with a significant influence on PTFS were seen. In multivariate analysis, an impact of FIGO stage on OS (p = 0.05) and DMFS (p = 0.014) was detected, and of rectal D2cc on DMFS (p = 0.031). The overall QoL score was 63/100. Cognitive function was the least impaired (84/100), while role functioning was the worst (67/100). On the symptom scale, insomnia (46/100), fatigue (41/100), dyspnea (32/100), pain (26/100), and financial difficulties (25/100) were scored the worst. According to EORTC-QLQ-CX24, peripheral neuropathy (36/100) and lymphedema (32/100) occurred most frequently. Impaired sexual/vaginal functioning (32/100) and body image (22/100) were also frequently recorded.

CONCLUSION

In patients with advanced cervical cancer, a combination of RCT and BT remains an excellent treatment option. In terms of patient-reported long-term quality of life, specific support is needed to alleviate symptoms including lymphedema, peripheral neuropathy, and impaired sexual activity.

Intracavitary Applicator for Sequential Delivery of Localized Hyperthermia Through Non-Metallic Uterine Tandem

In this article, we report the design and demonstration of a flexible coaxial wire antenna with a low profile flexible choke for delivering localized hyperthermia (HT) treatment to the cervix through a custom designed uterine tandem applicator. Resistive and magnetic materials were investigated for determining the flexible choke design suited for intracavitary HT treatment at 915 MHz. Measurements of the intracavitary antenna with the flexible choke in tissue mimicking phantom and ex-vivo bovine muscle through the non-metallic uterine tandem prototype confirm the ability to deliver localized HT to the cervix at 915 MHz and 50 mm insertion depth.

Feasibility of 4D HDR brachytherapy source tracking using x-ray tomosynthesis: Monte Carlo investigation

PURPOSE

High dose rate (HDR) brachytherapy rapidly delivers dose to targets with steep dose gradients. This treatment method must adhere to prescribed treatment plans with high spatiotemporal accuracy and precision, as failure to do so may degrade clinical outcomes. One approach to achieving this goal is to develop imaging techniques to track HDR sources in vivo in reference to surrounding anatomy. This work investigates the feasibility of using an isocentric C-arm x-ray imager and tomosynthesis methods to track Ir-192 HDR brachytherapy sources in vivo over time (4D).

METHODS

A tomosynthesis imaging workflow was proposed and its achievable source detectability, localization accuracy, and spatiotemporal resolution were investigated in silico. An anthropomorphic female XCAT phantom was modified to include a vaginal cylinder applicator and Ir-192 HDR source (0.5 × 0.5 × 5.0 mm3 ), and the workflow was carried out using the MC-GPU Monte Carlo image simulation platform. Source detectability was characterized using the reconstructed source signal-difference-to-noise-ratio (SDNR), localization accuracy by the absolute 3D error in its measured centroid location, and spatiotemporal resolution by the full-width-at-half-maximum (FWHM) of line profiles through the source in each spatial dimension considering a maximum C-arm angular velocity of 30° per second. The dependence of these parameters on acquisition angular range (θtot = 0°-90°), number of views, angular increment between views (Δθ = 0°-15°), and volumetric constraints imposed in reconstruction was evaluated. Organ voxel doses were tallied to derive the workflow's attributable effective dose.

RESULTS

The HDR source was readily detected and its centroid was accurately localized with the proposed workflow and method (SDNR: 10-40, 3D error: 0-0.144 mm). Tradeoffs were demonstrated for various combinations of image acquisition parameters; namely, increasing the tomosynthesis acquisition angular range improved resolution in the depth-encoded direction, for example from 2.5 mm to 1.2 mm between θtot = 30o and θtot = 90o , at the cost of increasing acquisition time from 1 to 3 s. The best-performing acquisition parameters (θtot = 90o , Δθ = 1°) yielded no centroid localization error, and achieved submillimeter source resolution (0.57 × 1.21 × 5.04 mm3 apparent source dimensions, FWHM). The total effective dose for the workflow was 263 µSv for its required pre-treatment imaging component and 7.59 µSv per mid-treatment acquisition thereafter, which is comparable to common diagnostic radiology exams.

CONCLUSIONS

A system and method for tracking HDR brachytherapy sources in vivo using C-arm tomosynthesis was proposed and its performance investigated in silico. Tradeoffs in source conspicuity, localization accuracy, spatiotemporal resolution, and dose were determined. The results suggest this approach is feasible for localizing an Ir-192 HDR source in vivo with submillimeter spatial resolution, 1-3 second temporal resolution and minimal additional dose burden.

Boost modalities in cervical cancer: dosimetric comparison between intracavitary BT vs. intracavitary + interstitial BT vs. SBRT

PURPOSE / OBJECTIVE

This study compares the dosimetric plans of three distinct boost modalities in cervical cancer (CC): intracavitary (IC) with tandem/ovoids brachytherapy (BT), IC + interstitial (IS) BT, and Stereotactic-Body-Radiotherapy (SBRT). The aim is to determine the dosimetric impact in terms of target coverage and organ at risk (OAR) doses.

MATERIALS AND METHODS

24 consecutive IC + IS BT boost treatment plans were retrospectively identified. For each plan included, two additional plans were created: IC-BT and SBRT. Importantly, no planning target volume (PTV) or planning (organ at) risk volume (PRV) margins were generated, therefore all structures were identical for any boost modality. Two different normalizations were performed: (1) Normalization to the target: prescription of 7.1 Gy to the D90% (defined as the minimum dose covering 90%) of the high-risk clinical target volume (HR-CTV); (2) Normalization to the OARs. HR-CTV coverage and OARs sparing were compared. The equivalent doses in 2 Gy fractions (EQD2) of EBRT and BT for CTV-HR and OARs were calculated using the linear-quadratic model with α/β of 10 (EQD2₁₀) and 3 (EQD2₃), respectively RESULTS: A total of 72 plans were investigated. In the first normalization, the mean EQD2_3-D2cc (defined as the minimal dose of the 2 cc) of OAR was significantly higher in the IC-BT plans, and the bladder D2cc hard constraint could not be reached. IC + IS BT leads to a 1 Gy mean absolute decrease of bladder EQD2₃-D2cc (relative dose: -19%), allowing to reach the hard constraint. SBRT (without PTV) delivers the lowest EQD2₃-D2cc to the OAR. In the second normalization, IC-BT provides a significantly lower dose to the EQD2₁₀-D90% (6.62 Gy) and cannot achieve the coverage goal. SBRT (without PTV) yields the highest dose to the D90% of HR-CTV and a significantly lower EQD2₁₀-D50% and D30%.

CONCLUSION

The key dosimetric benefit of BT over SBRT without PTV is a significantly higher D50% and D30% in the HR-CTV, which increases the local and conformal dose to the target. IC + IS BT vs. IC-BT provides significantly better target coverage and a lower dose to the OARs, making it the preferred boost modality in CC.

A 3D-Printable, Low-Cost Obturator for Less Invasive Gynecologic Brachytherapy

The purpose of this report is to design, develop, and evaluate a cost-effective applicator for interstitial brachytherapy (ISBT) to minimize patient morbidity and facilitate access to curative radiation treatment for gynecologic cancers, especially in low-resource settings. A computer-aided design and prototype were developed of a proposed applicator that incorporates 44 slotted channels to gently guide needles, with or without a tandem, through the vaginal canal, effectively eliminating the need for transcutaneous needle insertions typically employed during ISBT of advanced gynecologic cancer and thus reducing the risk of vaginal laceration and bladder or rectal injury. The tested prototype was developed using AutoCAD software (Autodesk, San Francisco, CA) and 3D printed in Accura Xtreme Gray material using stereolithography. Small-scale iterative tests using a gelatin phantom were conducted on this prototype to confirm the efficacy of the applicator through inter-operator usability, needle stability, and needle arrangement. A promising prototype was developed aimed at addressing key issues with traditional perineum-based templates to facilitate ISBT, including being able to cover bulky tumors with parametrial extension reliably, decrease the risk of tissue or organ injury, and treat women with a prior hysterectomy. Results of preclinical testing demonstrated that the applicator met its purpose, suggesting that it may facilitate ISBT without the morbidity typically associated with the procedure, especially by addressing concerns associated with implementing the procedure in low-resource settings. The applicator shows substantial promise in the treatment of advanced gynecologic cancer. While further testing remains necessary to confirm its translatability to the clinical setting, the applicator appears capable of meeting its design objectives, representing its potential for improving upon current methods.

Clinical outcomes of patients treated with template-based high-dose-rate interstitial brachytherapy boost for post-operative recurrent gynecological malignancies: A retrospective analysis

Purpose

To report the clinical outcomes in patients treated with Martinez universal perineal interstitial template (MUPIT)-based interstitial brachytherapy boost for primary and recurrent vault and vaginal cancers, and to perform a comparative analysis with our previously published series of similar patients.

Material and methods

One hundred and seventeen patients treated between January, 2009 and December, 2015 were evaluated. Descriptive statistics for the patterns of relapse, local recurrence-free survival (LRFS), disease-free survival (DFS), overall survival (OS), and late toxicities were carried out. Kaplan-Meier curves were used for survival analysis. All variables with the potential to affect outcomes were tested using log-rank test for statistical significance.

Results

At a median follow-up of 63 months, LRFS, DFS, and OS at 3/5 years were 77.1%/74.7%, 61%/52%, and 72.3%/63.1%, respectively. Overall treatment time (OTT) of 56 days did not affect outcomes. Bulky tumors and OTT > 63 days adversely affected LRFS. Overall treatment time also significantly impacted DFS and OS. Grade 3-4 late bladder toxicities were observed in 1.7% patients, and grade 3-4 late rectal toxicities in 5% patients. Compared to our previous series, the outcome in the current series is better in terms of severe late toxicities (5% improvement in rectal toxicity, and 2.7% improvement in bladder toxicity) and OS by 10%. This could be attributed to the increasing use of concurrent chemotherapy and relative optimization strategies for organs at risk.

Conclusions

Patients with primary and recurrent vault and vaginal cancers treated with high-dose-rate interstitial brachytherapy boost using MUPIT resulted in modest clinical outcomes and acceptable late toxicities. OTT was the most important factor affecting the outcomes.

Investigation of in vivo source tracking error thresholds for interstitial and intra-cavitary high-dose-rate cervical brachytherapy

Purpose

The purpose of this study was to determine a comprehensive in vivo source tracking error thresholds in high-dose-rate (HDR) brachytherapy for cervical cancer. Achieving this enables the definition of an action level for imminent in vivo source tracking technologies and treatment monitoring devices, preventing clinically relevant changes to the applied dose.

Material and methods

Retrospective HDR interstitial (n = 10) and intra-cavitary (n = 20) cervical brachytherapy patients were randomly selected to determine the feasibility of implementing in vivo source tracking error thresholds. A script was developed to displace all dwell positions in each treatment plan, along all major axes from their original position. Dose-volume histogram (DVH) indices were calculated without re-optimization of modified plans to determine the appropriate in vivo source tracking error thresholds in each direction.

Results

In vivo source tracking error thresholds were directionally dependent; the smallest were found to be 2 mm in the anterior and posterior directions for both interstitial and intra-cavitary treatments. High-risk clinical treatment volume (HR-CTV) coverage was significantly impacted by displacements of 4 to 5 mm along each axis. Critically, there was a large variation in DVH metrics with displacement due to change in dwell weightings and patient anatomy.

Conclusions

Determining the dosimetric impact of dwell position displacement provides a clinical benchmark for the development of pre-treatment verification devices and an action level for real-time treatment monitoring. It was established that an in vivo source tracking error threshold needs to be patient-specific. In vivo source tracking error thresholds should be determined for each patient, and can be conducted with extension of the method established in this work.

Comparison of vaginal gauze packing technique with or without balloon in high-dose-rate brachytherapy of uterine cervical cancer: A crossover randomized controlled trial

Purpose

To compare the rectal and bladder doses using two different vaginal packing techniques among uterine cervical cancer patients receiving high-dose-rate (HDR) intracavitary brachytherapy (ICBT).

Material and methods

Forty-five patients with cervical cancer were randomized to receive two sessions of ICBT using tandem and ring applicator (Varian^©), following completion of pelvic external beam radiotherapy treatment. The procedure was performed with vaginal balloon plus gauze packing or vaginal gauze packing alone, each of which was used in one of two sessions. Sequence of the type of vaginal packing was chosen with computer-generated block randomization. A HDR dose of 8.5 Gy was prescribed to point A in all patients. Volumetric dose parameters, such as D_0.1cc, D_0.5cc, D_1cc, and D_2cc of the rectum and bladder were compared between the two techniques of vaginal packing.

Results

The mean age of patients was 51 years. Majority (88%) of patients had locally advanced stages of cancer at baseline (stage IIB or more). Rectal doses were significantly less in combined packing technique (D_0.1cc: 7.52 Gy vs. 9.02 Gy, p = 0.01; D_0.5cc: 6.46 Gy vs. 7.42 Gy, p < 0.01; D_1cc: 5.91 Gy vs. 6.7 Gy, p < 0.01; D_2cc: 5.29 Gy vs. 5.97 Gy, p < 0.01). Bladder doses were higher in the combined packing technique (D_0.1cc: 11.20 Gy vs. 10.76 Gy, p = 0.18; D_0.5cc: 9.64 Gy vs. 9.32 Gy, p = 0.56; D_1cc: 8.64 Gy vs. 8.36 Gy, p = 0.55; D_2cc: 7.56 vs. 7.33 Gy, p = 0.55).

Conclusions

Combined vaginal packing resulted in statistically significant reduction in rectal radiation dose compared with standard vaginal gauze packing in high-dose-rate brachytherapy of cervix cancer using tandem and ring applicators.

Evolution of patterns of care for women with cervical cancer in Morocco over a decade

BACKGROUND

We conducted a Pattern-of-care (POC) study at two premier-most public-funded oncology centers in Morocco to evaluate delays in care continuum and adherence to internationally accepted treatment guidelines of cervical cancer.

METHOD

Following a systematic sampling method, cervical cancer patients registered at Centre Mohammed VI (Casablanca) and Institut National d'Oncologie (Rabat) during 2 months of every year from 2008 to 2017, were included in this retrospective study. Relevant information was abstracted from the medical records.

RESULTS

A total of 886 patients was included in the analysis; 59.5% were at stage I/II. No appreciable change in stage distribution was observed over time. Median access and treatment delays were 5.0 months and 2.3 months, respectively without any significant temporal change. Concurrent chemotherapy was administered to 57.7% of the patients receiving radiotherapy. Surgery was performed on 81.2 and 34.8% of stage I and II patients, respectively. A very high proportion (85.7%) of operated patients received post-operative radiation therapy. Median interval between surgery and initiation of radiotherapy was 3.1 months. Only 45.3% of the patients treated with external beam radiation received brachytherapy. Radiotherapy was completed within 10 weeks in 77.4% patients. An overall 5-year disease-free survival (DFS) was observed in 57.5% of the patients - ranging from 66.1% for stage I to 31.1% for stage IV. Addition of brachytherapy to radiation significantly improved survival at all stages. The study has the usual limitations of retrospective record-based studies, which is data incompleteness.

CONCLUSION

Delays in care continuum need to be further reduced. Increased use of chemoradiation and brachytherapy will improve survival further.

A Three-Dimensional Printable Hydrogel Formulation for the Local Delivery of Therapeutic Nanoparticles to Cervical Cancer

Cervical cancer is the fourth most common malignancy among women. Compared to other types of cancer, therapeutic agents can be administrated locally at the mucosal vaginal membrane. Thermosensitive gels have been developed over the years for contraception or for the treatment of bacterial, fungal, and sexually transmitted infections. These formulations often carry therapeutic nanoparticles and are now being considered in the arsenal of tools for oncology. They can also be three-dimensionally (3D) printed for a better geometrical adjustment to the anatomy of the patient, thus enhancing the local delivery treatment. In this study, a localized delivery system composed of a Pluronic F127-alginate hydrogel with efficient nanoparticle (NP) release properties was prepared for intravaginal application procedures. The kinetics of hydrogel degradation and its NP releasing properties were demonstrated with ultrasmall gold nanoparticles (∼80% of encapsulated AuNPs released in 48 h). The mucoadhesive properties of the hydrogel formulation were assayed by the periodic acid/Schiff reagent staining, which revealed that 19% of mucins were adsorbed on the gel's surface. The hydrogel formulation was tested for cytocompatibility in three cell lines (HeLa, CRL 2616, and BT-474; no sign of cytotoxicity revealed). The release of AuNPs from the hydrogel and their accumulation in vaginal membranes were quantitatively measured in vitro/ex vivo with positron emission tomography, a highly sensitive modality allowing real-time imaging of nanoparticle diffusion (lag time to start of permeation of 3.3 h, 47% of AuNPs accumulated in the mucosa after 42 h). Finally, the potential of the AuNP-containing Pluronic F127-alginate hydrogel for 3D printing was demonstrated, and the geometrical precision of the 3D printed systems was measured by magnetic resonance imaging (<0.5 mm precision; deviation from the design values <2.5%). In summary, this study demonstrates the potential of Pluronic F127-alginate formulations for the topical administration of NP-releasing gels applied to vaginal wall therapy. This technology could open new possibilities for photothermal and radiosensitizing oncology applications.

Furin-responsive triterpenine-based liposomal complex enhances anticervical cancer therapy through size modulation

The accumulation and penetration of antitumor drugs in tumor tissues are directly related to their antitumor effects. The particle size of the nanodrug delivery system is one of the most important factors for the accumulation and penetration of antitumor drugs within tumor tissues. Generally, nanodelivery systems of intermediate size (100–120 nm) are capable of efficient accumulation owing to prolonged circulation and enhanced permeability and retention (EPR) effect; however, smaller ones (20–40 nm) are effective for deep penetration within tumor tissue. Currently a conventional drug delivery system cannot possess two types of optimal sizes, simultaneously. To solve this and to enhance cervical cancer treatment, a furin-responsive triterpenine-based liposomal complex (PEGcleavable Tf-CTM/L), with Tf-CTM (transferrin-modified tripterine-loaded coix seed oil microemulsion) in core, coated with a thermo-sensitive lipid and a kind of PEG shell modified with a furin-cleavable peptide was developed to improve tumor-specific accumulation and penetration. Herein, PEGcleavable Tf-CTM/L was capable of efficient accumulation because of EPR effect. The PEG shells could timely detach under stimulation of overexpressed furin protein to solve the problem of the steric hindrance dilemma. The small-sized Tf-CTM released under stimulation of tumor microthermal environment in cervical cancer, which was efficient with regards to deep penetration at tumor sites. Notably, compared to the use of triterpenine alone, PEGcleavable Tf-CTM/L promoted anticervical efficacy and displayed diminished systemic toxicity by efficient accumulation and deep penetration of antitumor drugs within tumor tissues. Our study provides a new strategy, and holds promising potential for anticervical cancer treatment.

Radiosensitization using hydrogen peroxide in patients with cervical cancer

The purpose of the present study was to analyze the feasibility and safety of radiosensitization using hydrogen peroxide for cervical cancer. In superficial tumors, breast cancer and hepatocellular carcinoma, the safety and effectiveness of radiosensitization has been reported; to the best of our knowledge, however, there are no reports on cervical cancer. A total of 20 patients with cervical cancer were recruited. Inclusion criteria were as follows: Patients who required radical external beam radiotherapy (RT); ineligible for or refused brachytherapy; age, ≥20 years; no hematogenous metastasis; Eastern Cooperative Oncology Group Performance Status up to 2; and had not undergone prior treatment. Hydrogen peroxide was used twice a week in combination with RT. A 3% hydrogen peroxide solution-soaked gauze was inserted into the vagina during RT. A total of 45 Gy was delivered in 25 fractions to the whole pelvis with a boost of 10 Gy in 5 fractions if pelvic or para-aortic metastatic lymph nodes were observed. Ultimately, 18 patients were evaluated. Among the 17 patients (excluding one patient with tumor in situ), the one- and two-year overall survival rates were both 90% in patients with stage I/II and 86% in stage III/IV cervical cancer. The adverse events were well tolerated with no severe acute or late adverse events. Although limited by small sample size, short observation time and low radiation dose, the present study demonstrated that radiosensitization treatment may be an option for patients who cannot undergo brachytherapy. The study was retrospectively registered at the university hospital medical information network center (no. UMIN000039045) on January 6, 2020.

Reproducibility of vaginal immobilization balloons in situ overnight for cervical cancer brachytherapy

Purpose

The use of vaginal immobilization balloons placed into the vagina for immobilization of tandem and ovoid (T+O) applicator during high-dose-rate (HDR) brachytherapy delivery has been used at our institution, and seems to have improved our patient comfort, decreased procedure time, and minimized applicator misplacement. We aimed to show that these balloons, while originally marketed for single-day use, are safe and maintain applicator positioning/dosimetry when left in situ overnight for treatment delivery on sequential days.

Material and methods

Forty-two paired computed tomography (CT) scans from thirteen patients who underwent T+O HDR treatments on sequential days with vaginal immobilization balloons in situ overnight were retrospectively compared to calculate mean change of balloon volumes and balloon/T+O distance to bony landmarks. Dosimetric planning was retroactively performed on day 2 using CT scan of each pair, and the change in estimated radiation delivery to the bladder and rectum was compared.

Results

No statistically significant overnight changes were found in balloon volumes or anterior balloon positioning. The posterior balloon shifted -0.29 ±0.46 cm (p = 0.03) to the anterior public symphysis and 0.32 ±0.50 cm (p = 0.01) to the right femoral head. The tandem shifted 0.37 ±0.39 cm (p = 0.002) to the pubic symphysis. There was no significant difference found in radiation delivered to the bladder or rectum between the paired scans.

Conclusions

This study showed minimal change in balloon volumes, balloons/T+O positioning, or in radiation dose to bladder and rectum when the applicator remained overnight. These findings support that inflatable vaginal immobilization balloons remaining in situ overnight for additional HDR T+O treatments on sequential days, is safe and provides stable dosimetry.

Development of a Machine Learning Model for Optimal Applicator Selection in High-Dose-Rate Cervical Brachytherapy

Purpose

To develop and validate a preliminary machine learning (ML) model aiding in the selection of intracavitary (IC) versus hybrid interstitial (IS) applicators for high-dose-rate (HDR) cervical brachytherapy.

Methods

From a dataset of 233 treatments using IC or IS applicators, a set of geometric features of the structure set were extracted, including the volumes of OARs (bladder, rectum, sigmoid colon) and HR-CTV, proximity of OARs to the HR-CTV, mean and maximum lateral and vertical HR-CTV extent, and offset of the HR-CTV centre-of-mass from the applicator tandem axis. Feature selection using an ANOVA F-test and mutual information removed uninformative features from this set. Twelve classification algorithms were trained and tested over 100 iterations to determine the highest performing individual models through nested 5-fold cross-validation. Three models with the highest accuracy were combined using soft voting to form the final model. This model was trained and tested over 1,000 iterations, during which the relative importance of each feature in the applicator selection process was determined.

Results

Feature selection indicated that the mean and maximum lateral and vertical extent, volume, and axis offset of the HR-CTV were the most informative features and were thus provided to the ML models. Relative feature importances indicated that the HR-CTV volume and mean lateral extent were most important for applicator selection. From the comparison of the individual classification algorithms, it was found that the highest performing algorithms were tree-based ensemble methods – AdaBoost Classifier (ABC), Gradient Boosting Classifier (GBC), and Random Forest Classifier (RFC). The accuracy of the individual models was compared to the voting model for 100 iterations (ABC = 91.6 ± 3.1%, GBC = 90.4 ± 4.1%, RFC = 89.5 ± 4.0%, Voting Model = 92.2 ± 1.8%) and the voting model was found to have superior accuracy. Over the final 1,000 evaluation iterations, the final voting model demonstrated a high predictive accuracy (91.5 ± 0.9%) and F1 Score (90.6 ± 1.1%).

Conclusion

The presented model demonstrates high discriminative performance, highlighting the potential for utilization in informing applicator selection prospectively following further clinical validation.

Quality Assurance in Modern Gynecological HDR-Brachytherapy (Interventional Radiotherapy): Clinical Considerations and Comments

Simple Summary

This is a focused review discussing quality assurance during interventional brachytherapy in gynecological cancers. This topic is very large and is usually addressed from the technical and physical sides, therefore, we decided to select “hot-spots” under this large title and discuss them from the point of view of clinicians. We hope that this concise and focused review will help clinicians in improving their quality assurance protocols and draw attention to the discussed issues.

Abstract

The use of brachytherapy (interventional radiotherapy) in the treatment of gynecological cancers is a crucial element in both definitive and adjuvant settings. The recent developments in high-dose rate remote afterloaders, modern applicators, treatment-planning software, image guidance, and dose monitoring systems have led to improvement in the local control rates and in some cases improved the survival rates. The development of these highly advanced and complicated treatment modalities has been accompanied by challenges, which have made the existence of quality assurance protocols a must to ensure the integrity of the treatment process. Quality assurance aims at standardizing the technical and clinical procedures involved in the treatment of patients, which could eventually decrease the source of uncertainties whether technical (source/equipment related) or clinical. This commentary review sheds light (from a clinical point of view) on some potential sources of uncertainties associated with the use of modern brachytherapy in the treatment of gynecological cancers.

Outcomes of patients with cervical cancer treated with low- or high-dose rate brachytherapy after concurrent chemoradiation

OBJECTIVE

The majority of patients with cervical cancer in Ghana present with locally advanced disease. In October 2014, high-dose rate (HDR) brachytherapy was introduced at the National Center for Radiotherapy, Accra after years of using low-dose rate (LDR) brachytherapy. The aim of this study was to compare the treatment outcomes of patients treated with LDR versus HDR brachytherapy.

METHODS

Patients with cervical cancer treated from January 2008 to December 2017 were reviewed. Those with stage IB-IIIB who received chemoradiation plus brachytherapy were included in the study. Post-operative patients and those with stage IV were excluded. The study end points were local control, disease-free survival, and overall survival at 2 years. Endpoints were estimated using the Kaplan-Meier method. Comparisons between treatment groups were performed using the log-rank test and Cox proportional hazards model.

RESULTS

We included 284 LDR and 136 HDR brachytherapy patients. For stages IB, IIA, IIB, IIIA and IIIB disease, the 2-year local control for LDR versus HDR brachytherapy was 63% and 61% (p=0.35), 86% and 90% (p=0.68), 86% and 88% (p=0.83), 66% and 60% (p=0.56), and 77% and 40% (p=0.005), respectively. The 2-year disease-free survival for LDR versus HDR brachytherapy was 64% and 61% (p=0.50), 81% and 69% (p=0.18), 81% and 80% (p=0.54), 62% and 33% (p=0.82), and 71% and 30% (p=0.001) for stages IB, IIA, IIB, IIIA, and IIIB, respectively. The 2-year overall survival for LDR versus HDR brachytherapy was 94% and 93% (p=0.92), 98% and 68% (p=0.21), 89% and 88% (p=0.60), and 88% and 82% (p=0.34) for stages IB, IIA, IIB, and IIIB disease, respectively.

CONCLUSION

There was no difference between LDR and HDR brachytherapy in local control and disease-free survival for all stages of disease, except in stage IIIB. These findings highlight the need to refine this brachytherapy technique for this group of patients.

Preliminary results of modified interstitial MIAMI brachytherapy applicator for treatment of upper and apical vaginal tumors

Purpose

Intracavitary vaginal brachytherapy (VBT) cylinders are limited in treating upper/apical vaginal disease due to the distance between the target and radiation source positions. Interstitial brachytherapy devices directly expose the vaginal mucosa to radiation sources, increasing morbidity. To target apical disease while limiting excessive treatment to the vaginal mucosa and organs at risk, we modified the commercially available multichannel MIAMI applicator, allowing the direct extension of needles into the apex with the protection of cylinder.

Material and methods

The device has one central plastic core with six peripheral channels. The modified device permits titanium needles to surpass the apical surface into vaginal tissue. A retrospective analysis on thirteen patients treated with this device was conducted. Patient demographics, gross tumor volume (GTV)/clinical target volume (CTV), initial diagnosis and management, toxicity data, and EQD₂ data for the bladder and rectum were obtained.

Results

There were ten patients with vaginal recurrences and three with primary vaginal/cervical cancers. Mean dosage of VBT treatment was 25.5 Gy in 3-5 fractions. Mean dosage of external beam radiation therapy (EBRT) treatment was 44 Gy. Common acute toxicities included diarrhea, fatigue, cystitis, and nausea. Common chronic toxicities were pelvic pain, vaginal stenosis, and skin telangiectasia. Mean EQD₂ dose for bladder and rectum were 72.3 Gy and 62.3 Gy, respectively. Ten patients had no evidence of relapse, two suffered from distant metastases, and one patient with stage IIIA cervical adenocarcinoma had loco-regional recurrence seventeen months after radiation treatment.

Conclusions

Our data suggests that the custom applicator is associated with robust dosimetric coverage, good loco-regional control, acceptable toxicity, and reduced tissue trauma. This device allows treatment of apically located vaginal tumors without significant damage to the vaginal vault and organs at risk. Additionally, it provides the flexibility to treat multiple patients with variable vaginal diameters and sizes/depths of apical tumors using a single device.

Radiotherapy and Its Intersections with Surgery in the Management of Localized Gynecological Malignancies: A Comprehensive Overview for Clinicians

Surgery, including minimally invasive surgery, and radiotherapy are key modalities in the treatment of gynecological malignancies. The aim of this review is to offer the multidisciplinary care team a comprehensive summary of the intersections of surgery and radiotherapy in the local treatment of gynecological malignancies. Recent advances in radiotherapy are highlighted. Relevant publications were identified through a review of the published literature. Ovarian, endometrial, cervical, vaginal, and vulvar cancer were included in the search. Current guidelines are summarized. The role of radiotherapy in adjuvant as well as definitive treatment of these entities is synthesized and put into context with surgery, focusing on survival and quality of life. Although these outcomes have improved recently, further research must be focused on the number of life years lost, and the potential morbidity encountered by patients.

Prognostic Significance of Tumor Regression Rate during Concurrent Chemoradiotherapy in Locally Advanced Cervix Cancer: Analysis by Radiation Phase and Histologic Type

This study aimed to evaluate the prognostic significance of tumor regression rate according to radiation phase and histologic subtype in patients with locally advanced cervical cancer (LACC) treated with chemoradiation. We retrospectively reviewed the medical records of 398 patients with FIGO stage IIB-IVA cervical cancer treated with concurrent chemoradiotherapy (CCRT) between 2001 and 2019. Tumor response was assessed using serial magnetic resonance imaging (MRI) at three time points: pre-treatment, post-external beam radiotherapy (EBRT), and post-intracavitary radiotherapy (ICR). Tumor regression pattern according to histologic subtype and radiation phase (EBRT and ICR) was evaluated. Overall survival (OS) and progression-free survival (PFS) were the primary outcomes. Of 398 patients, 44 patients had adenocarcinoma/adenosquamous carcinoma (AC/ASC) and 354 patients had squamous cell carcinoma (SCC). AC/ASC was associated with significantly worse PFS and OS than SCC (p < 0.001). AC/ASC had a relatively poorer regression rate in response to EBRT than SCC (p < 0.001), whereas there was no significant difference in overall tumor regression rate after completion of RT (EBRT and ICR) between the two histologic subtypes. Multivariable analysis demonstrated AC/ASC histology to be an independent prognostic factor of decreased PFS and OS. Moreover, tumor regression rate after completion of EBRT (post-EBRT tumor regression rate (EBRT_regression ≤ 26%) and proportion of tumor regression during EBRT to overall tumor regression (EBRT_proportion ≤ 40%) were independent predictors of poor survival in patients with LACC. Tumor regression pattern of LACC in response to CCRT differs according to histologic subtype. AC/ASC histology and poor tumor response to EBRT are independent prognostic factors for worse survival in patients with LACC. Further studies are needed to develop a CCRT protocol that is specialized for patients with AC/ASC.

CAF-1/p150 promotes cell proliferation, migration, invasion and predicts a poor prognosis in patients with cervical cancer

Cervical cancer is one of the most common malignancies among women worldwide that exhibits high morbidity and mortality rates. Thus, the discovery of novel molecules and targets for cervical cancer diagnosis and treatment is critical. The present study aimed to investigate the role of the chromatin assembly factor (CAF)-1 subunit, CAF-1/p150 on cervical cancer cell proliferation, migration and invasion. Immunohistochemical analysis was used to detect the CAF-1/p150 expression in cervical cancer tissues and to analyze the association between CAF-1/p150 expression and the prognosis of patients with cervical cancer. In addition, colony formation, wound healing and Transwell assays were used to assess the function of CAF-1/p150 in cervical cancer cells. The results demonstrated that CAF-1/p150 was expressed in both normal and cervical cancer tissues. CAF-1/p150 protein expression was localized in the cell nuclei and was highly expressed in cervical cancer tissues. Furthermore, high CAF-1/p150 expression was significantly associated with FIGO stage, local recurrence, distant metastasis and a shorter overall survival time of patients with cervical cancer. CAF-1/p150 knockdown attenuated the anchorage-independent proliferation, migration and invasion of Hela and SiHa cervical cancer cells in vitro. Taken together, the results of the present study confirmed the involvement of CAF-1/p150 in the progression of cervical cancer, and validated its use as a poor prognostic indicator in patients with cervical cancer.

Stiff to Dilate and Risky to Cut Through: Iliac Radiation Arteritis

Radiation arteritis is not an uncommon clinical situation, given that almost 50% of patients with cancer receive radiotherapy in the course of treatment. Radiation effects are non-specific, and late radiation tissue injury presentation can be very variable. However, radiation arteritis has some unique clinical and radiological features, with consequent special therapeutic considerations. Iliac radiation arteritis may be accompanied by radiation-associated iliac vein disease and small vessel disease. Therefore, diagnostic and therapeutic plans should be directed toward all possible late radiation effects as relevant. Despite the complexity of the disease process and diagnostic challenges, treatment can be very straightforward if adequately planned. Otherwise, limb loss and/or life-threatening complications can rapidly ensue. This article highlights the natural history of radiation arteritis, with a particular emphasis on the iliac segment, and discusses the risk potentials of this condition, given that limb loss may be multifactorial, not merely because of the iliac arterial flow interruption. The main lines of management are also briefly discussed.

Oral Gastrografin Facilitates Delineation of Intestinal Tracts in CT-Based Brachytherapy for Uterine Cervical Cancer

Three-dimensional image-guided brachytherapy (3D-IGBT) using computed tomography (CT) is an essential component of definitive radiation therapy for uterine cervical cancer (UCC). Treatment planning for CT-based 3D-IGBT requires delineating the high-risk clinical target volume (CTV_HR) and the organs at risk (OARs), which is difficult when the small intestine is adjacent to those delineation targets. Uncertainty in target delineation threatens the validity of 3D-IGBT treatment plans. To address this issue, we introduce the use of diatrizoate meglumine and diatrizoate sodium (gastrografin), an orally administrable iodine-based radiopaque contrast agent. We present two cases of UCC treated with CT-based 3D-IGBT and describe how intraluminal enhancement of the small intestine by oral gastrografin pretreatment facilitated discrimination between the small intestine and the adjacent CTV_HR (case no.1) or the rectosigmoid colon (case no. 2). Oral gastrografin pretreatment is a simple and cost-effective method that allows distinguishing the small intestine from the adjacent delineation target (i.e., CTV_HR and the OARs) in CT-based 3D-IGBT for UCC.

3D printer-based novel intensity-modulated vaginal brachytherapy applicator: feasibility study

Purpose

To design a novel high-dose-rate intracavitary applicator which may lead to enhanced dose modulation in the brachytherapy of gynecological cancers.

Material and methods

A novel brachytherapy applicator, auxiliary equipment and quality control phantom were modeled in SketchUp Pro 2017 modeling software and printed out from a MakerBot Replicator Z18 three-dimensional printer. As a printing material polylactic acid (PLA) filament was used and compensator materials including aluminum, stainless-steel and Cerrobend alloy were selected according to their radiation attenuation properties. To evaluate the feasibility of the novel applicator, two sets of measurements were performed in a Varian GammaMed iX Plus high-dose rate iridium-192 (¹⁹²Ir) brachytherapy unit and all of the treatment plans were calculated in Varian BrachyVision treatment planning system v.8.9 with TG43-based formalism. In the first step, catheter and source-dwell positioning accuracy, reproducibility of catheter and source positions, linearity of relative dose with changing dwell times and compensator materials were tested to evaluate the mechanical stability of the designed applicator. In the second step, to validate the dosimetric accuracy of the novel applicator measured point dose and two-dimensional dose distributions in homogeneous medium were compared with calculated data in the treatment planning system using PTW VeriSoft v.5.1 software.

Results

In mechanical quality control tests source-dwell positioning accuracy and linearity of the designed applicator were measured as ≤ 0.5 mm and ≤ 1.5%, respectively. Reproducibility of the treatment planning was ≥ 97.7% for gamma evaluation criteria of 1 mm distance to agreement and 1% dose difference of local dose. In dosimetric quality control tests, maximum difference between measured and calculated point dose was found as 3.8% in homogeneous medium. In two-dimensional analysis, the number of passing points was greater than 90% for all measurements using gamma evaluation criteria of 3 mm distance to agreement and 3% dose difference of local dose.

Conclusions

The novel brachytherapy applicator met the necessary requirements in quality control tests.

A Dosimetric Analysis of the Rectal Doses in Intracavitary Brachytherapy of Carcinoma Cervix: A Prospective Study from a Single Institute

Introduction:

Carcinoma cervix is a common gynecologic malignancy in India and is treated with radical chemoradiation where intracavitary brachytherapy (ICR) is an integral part. In ICR of cervix, the two-dimensional (2D) point-based dosimetry cervix is the most common method used in high-volume centers with rectal dose calculation at modified ICRU rectal point with rectal wire placement. The rectal dose measurement using this method underestimates the dose to the rectum, and rectal dose also varies with the type of applicator used. The aim of our study is to compare the rectal dose calculated by ICRU 38 method versus rectal dose calculated by the rectal wire method using Henschke applicator.

Materials and Methods:

This is a single-institute, dosimetric comparison study done prospectively. Fifty patients were planned for ICR after 2D orthogonal radiograph-based, computer planning by iridium 192 high-dose rate remote afterloading technique after placing the appropriate Henschke applicator. The vaginal packing was done using sterile gauze with contrast material for defining the ICRU 38 rectal point, and a rectal wire was placed for the modified ICRU rectal point. Rectal doses were calculated by both the methods and compared.

Results:

The modified ICRU rectal point recorded a lower rectal dose (mean of 25%) compared to ICRU 38 rectal point in the study patients. There were ten patients (20%) with either too much or too little contrast material which made the visualization of the rectal point and radiation planning difficult. P value by paired t-test method was 0.0001, which was statistically significant.

Conclusion:

The modified ICRU rectal point is easier to visualize than ICRU 38 method (100% vs. 80%) for dosimetry, but it underestimates the rectal doses when compared to ICRU 38 rectal point. There needs to be a correction factor applied (25% in our study for Henschke applicator) when evaluating the rectal doses calculated by rectal wire method, to reduce the rectal toxicity.

Radical radiotherapy in patients with cervix uteri carcinoma: experience of Ondokuz Mayis University

Background

Radical radiotherapy is the standard treatment for patients with locally advanced cervix uteri carcinoma (FIGO stage IB2–IVA). Worldwide, incidence and mortality rates vary among regions because of differences in lifestyles and treatment standards. Herein, we evaluated the outcomes of radical radiotherapy in patients with locally advanced cervix uteri carcinoma from the middle Black Sea region of Turkey.

Methods

We retrospectively reviewed the records of 64 consecutive patients with locally advanced cervix uteri carcinoma who were treated from January 2013 to 2016 in our radiation oncology department. All patients staging and radiotherapy planning were performed with modern imaging techniques including magnetic resonance imaging and positron-emission-tomography/computed tomography before radical radiotherapy. Thereafter, all of them were treated with external beam radiotherapy and concurrent cis-platinum-based chemotherapy followed by three-dimensional intra-cavitary high-dose-rate brachytherapy.

Results

The median age at diagnosis was 54.5 years. The median follow-up period was 21 months. Acute grade 3 toxicity was detected in 3.1% of patients. Late toxicity was not detected in any patient. The 1- and 3-year progression-free survival rates were 83.6 and 67.5%, respectively. The 1- and 3-year overall survival rates were 95.7 and 76.9%, respectively. The most important prognostic factor was the FIGO stage. Distant metastasis was the most common cause of death in patients with locally advanced cervix uteri carcinoma despite radical radiotherapy.

Conclusions

In patients with locally-advanced cervix uteri carcinoma from the middle Black Sea region of our developing country, acceptable toxicity and survival rates are achieved similar to the recent literature from developed countries with using of modern staging, planning and radical radiotherapy techniques. However, recurrence was mostly in the form of distant metastases and further investigations on systemic therapies are required.

Dosimetric effects of the Smit sleeve on high-dose-rate brachytherapy tandem and ovoids plans for patients with locally advanced cervical cancer

Purpose

Smit sleeves are used to facilitate insertion of the intrauterine tandem during brachytherapy for cervical cancer. When a tandem and ovoids system is used the base of the Smit sleeve displaces the ovoids distally. The dosimetric impact of this displacement is not known. Herein we performed a dosimetric analysis to quantify this impact on the integral dose and dose delivered to the organs at risk (OARs).

Material and methods

Eleven high-dose-rate brachytherapy plans in which a Smit sleeve was used with a tandem and ovoids were reviewed. A second set of plans was generated modifying the position of the ovoids to simulate absence of the Smit sleeve. The high-risk clinical tumor volume (HR-CTV) dose coverage was maintained the same for both sets of plans by appropriately rescaling the dwell times of the simulated plan. The mean integral dose, D_2cc to the OARs (bladder, bowel, sigmoid and rectum) and the ICRU rectum point dose were compared between the original and modified plans using a paired two-sample t-test.

Results

Simulating removal of the Smit sleeve was associated with an average reduction in the mean integral dose of 6.1% (p < 0.001) and an average reduction of 10.9% (p = 0.004) to the rectal D_2cc. Doses to the remaining OARs decreased to a lesser magnitude with only that of the sigmoid being statistically significant.

Conclusions

The use of a Smit sleeve with a tandem and ovoids system could lead to the delivery of a higher mean integral dose to achieve similar HR-CTV coverage. In addition, it could increase the dose to surrounding OARs, primarily the rectum. The clinical significance of these findings is unknown, but the potential dosimetric impact of using a Smit sleeve should be taken into consideration during the planning when this device is used.

Preserving Endocrine Function in Premenopausal Women Undergoing Whole Pelvis Radiation for Cervical Cancer

Purpose

Whole pelvis radiation therapy (WPRT) in premenopausal women with cervical cancer can cause permanent ovarian damage, resulting in premature menopause. Oophoropexy, often considered as an initial step, demonstrates safety of sparing 1 ovary at the cost of delay in initiating WPRT. Therefore, we dosimetrically compared volumetric modulated arc radiotherapy (VMAT) and intensity modulated proton therapy (IMPT) techniques to allow for ovarian-sparing WPRT.

Materials and Methods

Ten patients previously treated for cervical cancer at our institution were included in this institutional review board-approved analysis. A modified clinical treatment volume (CTV) was designed, sparing 1 ovary (left or right), as determined by the physician (ovarian-sparing CTV) and disease extent, including physical exam, positron emission tomography/computed tomography and magnetic resonance imaging. An ovarian-sparing planning target volume was determined as the ovarian-sparing CTV+5 mm for patients who were supine and 7 mm for those who were prone. All plans were calculated to a dose of 45 Gy with specific optimization goals for target volumes, while attempting to maintain a mean ovary dose (D_mean) < 15 Gy. Dosimetric goals were compared across the 2 modalities using the Mann-Whitney U test.

Results

Both treatment modalities were able to achieve primary clinical goal coverage to the uterus/cervix (P = .529, comparing VMAT versus IMPT), ovarian-sparing CTV (P = .796) and ovarian-sparing planning target volume (P = .004). All 10 IMPT plans were able to accomplish the ovary objective (14.0 ± 1.66 Gy). However, only 4 of the 10 VMAT plans were able to achieve a D_mean < 15 Gy to the prioritized ovary, with an average dose of 15.3 ± 4.10 Gy.

Conclusion

Sparing an ovary in women undergoing WPRT for cervical cancer is dosimetrically feasible with IMPT without sacrificing coverage to important clinical targets. Future work will incorporate the brachytherapy dose to the ovarian-sparing CTV and assess the clinical response of this technique as a means to preserve ovarian endocrine function.

Treatment of locally advanced cervical cancer in a patient with a bicornuate uterus with MRI-guided intracavitary/interstitial brachytherapy

Purpose

Definitive treatment for locally advanced cervical cancer (LACC) includes external beam radiation therapy (EBRT) with concurrent cisplatin and brachytherapy. Image-guided intracavitary brachytherapy utilizes CT and/or MRI for target and organ at risk delineation and has been shown to improve local control rates and decrease toxicity. Hybrid intracavitary/interstitial applicators can be used to improve tumor coverage in certain cases. We describe the use of combined intracavitary/interstitial brachytherapy to treat a cervical cancer patient with a bicornuate uterus.

Case presentation

A 30-year-old female with bicornuate uterus and FIGO IB2 adenocarcinoma of the cervix was treated with 45 Gy of EBRT to the pelvis with concurrent weekly cisplatin. An examination after EBRT demonstrated a persistent bulky tumor covering most of the cervix. Brachytherapy was delivered via a combined intracavitary/interstitial approach, using a tandem and ring applicator and an interstitial needle. The placement of the tandem was alternated between uterine cornua with each fraction, and the interstitial needle was placed on the side opposite the tandem. CT and MRI were obtained with each fraction. The patient completed the treatment without complications. Three-month restaging PET-CT showed significant interval improvement in the cervix, with a complete clinical response on physical examination. The patient is without evidence of disease 18 months after the treatment.

Conclusions

We found that the use of the hybrid applicator allowed for adequate target coverage in a patient with unusual anatomy. The patient tolerated treatment well and demonstrated favorable response on follow-up exam and imaging. The long-term curative result needs to be further evaluated.

Hyaluronate gel injection for rectum dose reduction in gynecologic high-dose-rate brachytherapy: initial Japanese experience

Perirectal hyaluronate gel injection (HGI) appears to be a promising technique for healthy tissue dose sparing in pelvic radiotherapy. In this analysis, we report our initial experience of HGI in gynecologic brachytherapy, focusing on its safety and effectiveness for dose reduction to the rectum. Between July 2013 and May 2014, 36 patients received HGI for primary/salvage gynecologic brachytherapy. Dosimetric effect analysis was based on pre- and post-HGI computed tomography dataset registration with corresponding dose-volume histogram evaluation. The maximum dose to the most exposed 0.1 cm3 (D0.1cm3) and 2.0 cm3 (D2.0cm3) were used as index values for rectum and bladder dose evaluation. The dose indexes for target volume (TV) coverage were TV D90/V100. In all cases, HGI was well tolerated, with no acute or late adverse events documented at a median follow-up of 220 days (range, 18-1046 days). Rectum D2.0cm3 and D0.1cm3 were significantly decreased by HGI (P < 0.001 and P = 0.003, respectively), with no significant impact on dosimetric parameters of bladder and TV coverage. Factors correlating negatively with the dosimetric effect of HGI were an increasing number of interstitial catheters (P = 0.003) as well as Lcranial100% (P = 0.014) and Lcranial80% (P = 0.001) [i.e. the length from the anal verge to the most cranial point at which the 100% and 80% isodose lines, respectively, crossed the rectum]. The concept of HGI for gynecologic brachytherapy is plausible, and our initial experience indicates it to be an effective technique for rectal dose reduction in radiotherapy of intrapelvic tumours.

Cervical Cancer, Different Treatments and Importance of Bile Acids as Therapeutic Agents in This Disease

Cervical cancer can be cured, because it has a long preinvasive period. Early diagnosis and treatment of cervical cancer at women are crucial for reducing of rate mortality. Today, there are many methods for detecting premalignant lesions and one of them is a conventional Papanicolaou test. Cervical cancer develops through a series of changes in the epithelium called cervical intraepithelial neoplasia (CIN). The biological and genetic characteristics of the cells at cancer in situ are irreversibly altered and abnormal cells have the potential to metastasize to others anatomical regions. Infection with human Papillomavirus, which is transmitted sexually, is considered the main cause and represent the necessary, but not the only factor for the development of cervical cancer. Types of high risk human Papillomavirus are often associated with invasive cervical cancer. The carcinogenic types of HPV 16 and 18 are responsible for 70% of cervical cancer and about 50% of CIN 3. Primary prevention of cervical cancer is aimed at reducing incidence, control of causes and risk factors. In this scientific work, in addition to explaining the various treatments necessary for the treatment of cervical carcinoma, we were discussed about the anticancer effects of the synthetic derivative of ursodeoxycholic acid, such as HS-1183, and synthetic derivatives of chenodeoxycholic acid such as HS-1199 and HS-1200. Also, the effects of bile acid complexes with metals such as platinum, zinc, nickel, and copper were considered in the effective treatment of cervical cancer.

KEY POINTS

• Lymphogenic spreading of cervical cancer occurs relatively early in the regional lymph nodes, while this sort of progression of cervical cancer is rarer in the juxtaregional (paraaortic), mediastinal and supraclavicular nodes.

Clinically proven supraclavicular metastases are not a rarity. In stages IIb and IIIa with metastases in paraaortal nodes occur a 20% metastases at the neck lymph nodes.

Hematogenic metastases are relatively rare and occur in the posterior phase. Distant metastases are detected in the lungs and liver.

Preinvasive and microinvasive stages of cervical cancer are without symptoms. With deeper invasion of the strome, certain clinical symptoms such as prolonged menstruation, increased vaginal secretions, vaginal bleeding between the two periods, contact bleeding (after coitus), unilateral pelvic pain with spreading in hip joint (infiltration of the pelvic nerve plexus), dysuric disturbance, anemia, islet of the lower extremities.

In order to diagnose the level spreading of primary lesion of cervical cancer most commonly are used the supplemental searches such as cytoscopy, rectoscopy, urography, irigography, lung and bone radiography, scintigraphy of the liver, kidney and bone, lymphography, CT (MR) of abdomen and pelvis, as well as laboratory analysis.

Surgical treatment consists of transvaginal hysterectomy, transabdominal removal of the uterus (via laparotomy), bilateral adenectomy (removal of the ovaries and the fallopian tubes), upper and middle third of the vagina and lymphonodectomy of the regional lymph nodes. The most commonly used radiotherapy, intracavitary brachytherapy, manual afterloading technique and remote afterloading techniques.

The synthetic derivatives of ursodeoxycholic acid and chenodeoxycholic acid such as HS-1183, HS-1199, and HS-1200 are used to treat cervical cancer. These derivatives of chenodeoxycholic acid and ursodeoxycholic acid are capable of inhibiting cell proliferation and inducing apoptosis in SiHa human cells of cervix.

Platinum compounds are used as catalysts in cervical cancer therapy. Clinical use of platinum complexes for which the bile acids bind is based on the desire to achieve the death of tumor cells and the spectrum of drug activity in the treatment of cervical cancer.

Bisursodeoxycholate (ethylenediamine) platinum (II) [Pt(UDC)₂(en)] is characterized by important cytotoxicity against HeLa cervical carcinoma cells and this effect already being clearly detectable after 24 h.

Positron emission tomography for staging locally advanced cervical cancer and assessing intensity modulated radiotherapy approach

AIMS

To evaluate toxicity and outcome of concomitant chemotherapy and intensity modulated radiotherapy (IMRT) with 18-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸FDG-PET/CT) based simultaneous integrated boost (SIB) of locally advanced cervical cancer (LACC).

METHODS

Patients with LACC underwent chemo-radiation with IMRT and SIB. Staging and follow-up were performed with clinical evaluation and CT, MRI, ¹⁸FDG-PET/CT. SIB was done on positive nodes with ¹⁸FDG-PET/CT based planning. CT-based planning high-dose-rate brachytherapy (HDR-BT) was delivered as subsequent boost to the primary tumor. Cisplatin concomitant chemotherapy was administered during IMRT.

RESULTS

Fourteen patients with cervical cancer were prospectively recruited between August 2014 and June 2017, 13 (93%) had a LACC, one (7%) patient was not evaluable because ¹⁸FDG-PET/CT evidenced metastases to the liver undetected by previous CT/MRI. Patients had a median age of 59 years, a median Karnofsky performance status of 100%, and a prevalence of squamous cell carcinoma histology (85%). SIB was delivered on 23 positive lymph nodes. IMRT median dose to the pelvis was 48.6 Gy in 27 fractions, SIB median dose 54 Gy in 27 fractions, HDR-BT boost median dose 21 Gy in 3 fractions. After a median follow-up of 30 months, 2-year local control and distant control were 86% and 86%, respectively. There were no grade 4 acute and/or late toxicities.

CONCLUSIONS

The ¹⁸FDG-PET/CT influenced stage assessment and RT treatment planning due to its high specificity in distant metastases and nodal involvement detection. The IMRT with SIB for positive nodes was an effective therapy with acceptable toxicity in LACC.

Risk factors for fistula formation after interstitial brachytherapy for locally advanced gynecological cancers involving vagina

Purpose

To determine risk factors for fistula formation after interstitial brachytherapy (ISBT) in patients with advanced gynecologic cancers.

Material and methods

We performed an Institutional Review Board (IRB) approved retrospective review of 44 patients treated with transperineal template-based ISBT from 2011 to 2017 at a major metropolitan county and university health system. All patients were treated with image-guided high-dose-rate ISBT. Statistical analysis was performed using the χ² test to identify factors correlated with fistula formation. Survival and tumor control outcomes were calculated using Kaplan Meier analyses.

Results

Patients had a mean age of 53 years (range, 28-81 years), a mean external beam dose of 43.1 Gy (range, 42.5-51.3 Gy), and a mean brachytherapy dose of 22.8 Gy (range, 21.3-30 Gy). Two of 44 patients had fistulas that could be definitively attributed to therapy for a fistula rate of 4.5%. Six additional patients (13.6%) developed fistula after treatment with associated recurrent disease but were included in the causality analysis. We analyzed patient tumor and treatment factors, and on univariate analyses we found that age ≥ 60 years, Hispanic ethnicity, bladder involvement, rectal D2 cc ≥ 70 Gy, and whether patients had post-radiation biopsies were predictors for fistula formation. The 1-year overall survival (OS), progression-free survival (PFS), and local control (LC) were 85%, 58.5%, and 76.9%, respectively, with a mean follow-up time 23 months (range, 4.0-68.8 months).

Conclusions

We identified factors that predict fistula formation in patients with advanced gynecologic tumors treated with ISBT. These factors can be used to stratify patients into a high-risk group, with potential for modification of brachytherapy planning to reduce their risk of fistula formation.

Bleeding after interstitial brachytherapy for cervical cancer requiring embolization

Cervical cancer is the third most common cancer among women worldwide and is usually managed with chemoradiation in advanced disease. This case presents a 41-year-old female with locally advanced cervical cancer who underwent combination intracavitary/interstitial brachytherapy after chemoradiation for local disease control. At her fifth brachytherapy session, one of the interstitial needles was malpositioned and lead to vascular injury with significant blood loss. She subsequently underwent emergent embolization of a branch of the right obturator artery with immediate clinical improvement and no complications. This is the first reported case of vascular injury from an interstitial brachytherapy needle that required arterial embolization for hemostasis.

Clinical analysis of speculum-based vaginal packing for high-dose-rate intracavitary tandem and ovoid brachytherapy in cervical cancer

Purpose

Intra-vaginal packing is used to fix the applicator and displace organs at risk (OAR) during high-dose-rate intracavitary tandem and ovoid brachytherapy (HDR-ICB). We retain the speculum from applicator placement as a dual-function bladder and rectum retractor during treatment. Our objective is to review salient techniques for OAR displacement, share our packing technique, and determine the reduction in dose to OAR and inter-fraction variability of dose to OAR, associated with speculum-based vaginal packing (SBVP) in comparison to conventional gauze packing during HDR-ICB.

Material and methods

We reviewed HDR-ICB treatment plans for 45 patients, including 10 who underwent both conventional gauze packing and SBVP. Due to institutional inter-provider practice differences, patients non-selectively received either packing procedure. Packing was performed under conscious sedation, followed by cone beam computed tomography used for dosimetric planning. Maximum absolute and percent-of-prescription dose to the International Commission of Radiation Units bladder and rectal points in addition to D_0.1cc, D_1.0cc, and D_2.0cc volumes of the bladder and rectum were analyzed and compared for each packing method using an independent sample t-test.

Results

Of the 179 fractions included, 73% and 27% used SBVP and gauze packing, respectively. For patients prescribed 6 Gy to point A, SBVP was associated with reduced mean D_0.1cc bladder dose, inter-fraction variability in D_0.1cc bladder dose by 9.3% (p = 0.026) and 9.0%, respectively, and statistically equivalent rectal D_0.1cc, D_1.0cc, and D_2.0cc. Patients prescribed 5.5 Gy or 5 Gy to point A after dose optimization, were less likely to benefit from SBVP. In the intra-patient comparison, 80% of patients had reduction in at least one rectum or bladder parameter.

Conclusions

In patients with conducive anatomy, SBVP is a cost-efficient packing method that is associated with improved bladder sparing and comparable rectal sparing relative to gauze packing during HDR-ICB without general anesthesia.

Psychiatric Care of the Radiation Oncology Patient

BACKGROUND

In recent decades, psychiatrists have become increasingly involved in the care of patients with cancer. Psychiatrists are often less familiar with the field of radiation oncology than with other medical specialties.

OBJECTIVE

Therefore, it is beneficial for consulting psychiatrists to be familiar with the basic principles of radiation therapy (RT) and its potential neuropsychiatric sequelae.

METHODS

We performed a PubMed search to identify articles describing neuropsychiatric symptoms resulting from RT, including anxiety, claustrophobia, posttraumatic stress disorder, and neurocognitive impairment. We also searched for other sequelae of RT that may produce psychiatric symptoms, such as radiation necrosis and endocrinopathies. We provide a basic introduction to the delivery of RT.

RESULTS

Psychiatrists may be involved in the treatment of patients before, during, or after RT, and each phase of treatment produces unique considerations. Anxiety about the treatment, especially the need for immobilization with a mask, can be treatment-limiting. Adverse effects from treatment, including cognitive impairment and endocrinopathies, can result in psychiatric symptoms.

CONCLUSIONS

Consulting psychiatrists should be familiar with the basic principles of RT and the neuropsychiatric sequelae that may result from the treatment. Further research is needed to identify strategies to help patients tolerate RT and to identify additional preventive and therapeutic options for RT-induced cognitive impairment.

Assessing dose contribution to pelvic lymph nodes in intracavitary brachytherapy for cervical cancer

PURPOSE

In radical radiotherapy for cervical cancer, high-dose-rate (HDR) brachytherapy is commonly used after external beam radiation therapy (EBRT) to deliver a cumulative EQD2 of 80 to 90 Gy to the primary tumor. However, there is less certainty regarding brachytherapy dose contribution to the pelvic lymph nodes. This poses a challenge as to how high a preceding EBRT dose should be prescribed to gross nodal disease, in order to achieve a cumulative tumoricidal effect. Hence, this study aims to quantify brachytherapy dose contribution to individual pelvic nodal groups, using computed tomography (CT) planning with the Manchester system.

MATERIAL AND METHODS

This is a single institution retrospective dosimetric study. CT planning datasets from 40 patients who received EBRT followed by intracavitary HDR brachytherapy (5 or 6 Gy fractions) were retrieved. The external iliac (EI), internal iliac (II), and obturator (OB) lymph node groups were contoured on each CT dataset. Applying the initial brachytherapy plan, mean doses to each nodal group were calculated for every patient, and averaged across the respective (5 or 6 Gy) study populations.

RESULTS

With a brachytherapy dose of 5 Gy to Manchester point A, the mean absolute doses received by the EI, II, and OB groups were 0.79, 1.12, and 1.34 Gy respectively, corresponding to EQD2s (α/β = 10) of 0.71, 1.04, and 1.27 Gy respectively. With a brachytherapy dose of 6 Gy, the mean absolute doses received by the EI, II, and OB groups were 1.16, 1.56, and 1.80 Gy respectively, corresponding to EQD2s of 1.08, 1.49, and 1.77 Gy, respectively.

CONCLUSIONS

Our study demonstrates that pelvic lymph nodes receive substantial dose contributions from HDR brachytherapy in cervical cancer. This should be taken into account by the radiation oncologist during EBRT planning, and adequate external beam boost doses calculated to achieve cumulative tumoricidal doses to pelvic nodal disease.

Novel anesthetic technique for combined intracavitary and interstitial brachytherapy for cervix cancer in an outpatient setting

Purpose

To determine the feasibility and safety of outpatient combined intracavitary and interstitial brachytherapy for cervix cancer with sedation and local anesthesia.

Material and methods

We included patients diagnosed with non-metastatic cervix cancer and have completed brachytherapy between December 2015 and December 2016. Moderate to deep sedation was achieved using intravenous midazolam, propofol, fentanyl, and oxycodone. Local anesthesia was achieved with 2% lignocaine gel and a paracervical block containing a mixture of 1% ropivacaine, 2% lignocaine, and 1 : 1,000 adrenaline. Ceftriaxone and ondansetron were given prophylactically. Physiologic monitoring was performed throughout and pain scores were recorded using the Numeric Rating Scale. Follow-up was conducted at 8 weeks from the last fraction of brachytherapy. The feasibility and safety endpoints were a post-anesthesia discharge score (PADS) of 9 or above, and no grade 3 or above adverse events, respectively.

Results

A total of thirty-five brachytherapy insertions were carried out on nine patients. The median age of the patients was 56 years (range, 40-65). Eight patients had American Society of Anesthesiologists’ physical status of I or II, and one had a status of III. The mean duration of the insertion was 39 minutes (standard deviation [SD] = 14), during which no adverse events occurred. There was no significant nausea or vomiting post-sedation. The median pain scores post-insertion and during recovery were 0 (range, 0-6) and 0 (range, 0-7), respectively. At discharge, all patients had pain scores of 0 and maximum PADS of 10. The mean time to discharge was 4.1 hours (SD = 0.95). There were no brachytherapy-related admissions or complications.

Conclusions

Outpatient combined intracavitary and interstitial brachytherapy for cervix cancer with sedation and local anesthesia is feasible and safe. This could potentially lead to significant cost savings.

Metal artefacts in MRI-guided brachytherapy of cervical cancer

The importance of assessing the metal-induced artefacts in magnetic resonance imaging (MRI)-guided brachytherapy is growing along with the increasing interest of integrating MRI into the treatment procedure of cervical cancer. Examples of metal objects in use include intracavitary cervical applicators and interstitial needles. The induced artefacts increase the uncertainties in the clinical workflow and can be a potential obstacle for the accurate delivery of the treatment. Overcoming this problem necessitates a good understanding of its originating sources. Several efforts are recorded in the literature to quantify the extent of such artefacts, in phantoms and in clinical practice. Here, we elaborate on the origin of metal-induced artefacts in the light of brachytherapy applications, while summarizing recent efforts that have been made to assess and overcome the induced distortions.

Dosimetric analysis of Co-60 source based high dose rate (HDR) brachytherapy: A case series of ten patients with carcinoma of the uterine cervix

AIM

To analyse the dosimetric parameters of Co-60 based high dose rate (HDR) brachytherapy plans for patients of carcinoma uterine cervix.

BACKGROUND

Co-60 high dose rate (HDR) brachytherapy unit has been introduced in past few years and is gaining importance owing to its long half life, economical benefits and comparable clinical outcome compared to Ir-192 HDR brachytherapy.

MATERIALS AND METHODS

A study was conducted on ten patients with locally advanced carcinoma of the uterine cervix (Ca Cx). Computed tomography (CT) images were taken after three channel applicator insertions. The planning for 7 Gray per fraction (7 Gy/#) was done for Co-60 HDR brachytherapy unit following the American Brachytherapy Society (ABS) guidelines. All the patients were treated with 3# with one week interval between fractions.

RESULTS

The mean dose to high risk clinical target volumes (HRCTV) for D90 (dose to 90% volume) was found to be 102.05% (Standard Deviation (SD): 3.07). The mean D2cc (dose to 2 cubic centimeter volume) of the bladder, rectum and sigmoid were found to be 15.9 Gy (SD: 0.58), 11.5 Gy (SD: 0.91) and 4.1 Gy (SD: 1.52), respectively.

CONCLUSION

The target coverage and doses to organs at risk (OARs) were achieved as per the ABS guidelines. Hence, it can be concluded that the Co-60 HDR brachytherapy unit is a good choice especially for the centers with a small number of brachytherapy procedures as no frequent source replacement is required like in an Ir-192 HDR unit.

HOTAIR enhanced aggressive biological behaviors and induced radio-resistance via inhibiting p21 in cervical cancer

We previously reported the frequent overexpression of HOX Antisense Intergenic RNA (HOTAIR) in human cervical cancer, which was significantly correlated with tumor progression and poor prognosis. In the present study, we investigated the detailed biological functions of HOTAIR in cervical cancer. In vitro, upregulation of HOTAIR inhibited apoptosis and promoted cellular proliferation, cell cycle progression, migration, and invasion; on the contrast, downregulation of HOTAIR induced more apoptosis, suppressed cellular proliferation, cell cycle, migration, and invasion. Moreover, a high level of HOTAIR was notably associated with radio-resistance and downregulation of p21 in the primary cultured cervical cancer cells. Further, we demonstrated that elevated HOTAIR could induce radio-resistance via inhibiting p21 in HeLa cells, while knockdown of HOTAIR upregulated p21 and consequentially increased the radio-sensitivity of C33A cells. Consistently, stable knockdown of HOTAIR significantly suppressed tumor growth and sensitized cervical cancer to radiotherapy in vivo. In conclusion, HOTAIR served as an onco-lncRNA in cervical cancer which could enhance various aggressive biological behaviors. Moreover, we proved that HOTAIR execute its functions mainly through inhibiting the p21 expression. These results proposed that targeting HOTAIR might be a potent therapeutic strategy in cervical cancer, especially for those patients who accepted radiotherapy.

Cervical squamous cell carcinoma with isolated tibial metastasis: A case report and review of the literature

Bone metastasis resulting from carcinoma of the cervix is rare, particularly in the isolated distal appendicular bone. A 43-year-old female was diagnosed with a right tibial tumor with progressive right knee pain for three months, which was diagnosed as poorly differentiated metastatic squamous cell carcinoma, and further confirmed by biopsy of the proximal tibia. The patient was diagnosed with cervical squamous cell carcinoma with tibial metastasis following further examination, despite a lack of gynecological symptoms. In contrast to the poor outcome commonly observed in patients with bone metastasis, the patient survived and remained disease-free 41 months after surgical excision of the metastatic tumor and radical hysterectomy followed by chemoradiotherapy. The present case is one of the few documented cases of metastasis to the tibia arising from carcinoma of the uterine cervix and may be the first regarding isolated metastasis at this site.