Brachytherapy Techniques Research Articles

Patients-Reported Outcomes of Acute Side Effects During Head and Neck Cancer Radiotherapy: A Cross-Sectional Study at Andalas University Hospital Padang

Background: Head and neck cancer is a malignancy originating from the upper aerodigestive tract. Head and neck cancer patients undergoing radiotherapy using brachytherapy, 2DRT, 3CDRT, and IMRT techniques. Patients undergoing radiotherapy will experience several acute side effects consisting of mucositis, dysphagia, xerostomia, and dermatitis. This is influenced by the technique and dose given. This study aims to grade and time the acute side effects of radiotherapy for head and neck cancer at the Andalas University Hospital Padang. Methods: A quantitative descriptive method with a cross-sectional approach is used. Secondary data with a total sample of 88 patients. This research uses medical record data and is analyzed using statistical analysis methods. Results: This study found that the most head and neck cancer patients who underwent radiotherapy were male 57 (64.8%) patients, nasopharyngeal subsite 41 (46.6%) patients with non-keratinizing nasopharyngeal carcinoma 32 (36.4%) patients. The most common radiotherapy technique for head and neck cancer was IMRT in 58 (65.9%) patients with a dose of 61-70 Gy in 78 (88.6%) patients and the most common stage was IV A in 51 (58%) patients. Patients did not undergo chemotherapy treatment in 51 (58%) and surgery in 69 (78.4%). Body mass index (BMI) before radiotherapy was normal in 74 (84.1%) patients and after radiotherapy became underweight in 57 (64.8%) patients resulting in weight loss 1 kg in 83 (94.3%) patients. The highest grade of radiotherapy side effects was grade 1 which consisted of mucositis 84 (95.5%), dysphagia 83 (94.3%), xerostomia 78 (88.6%), and dermatitis 78 (88.6%) patients. The most frequent timing of mucositis side effects occurred in the 3rd week in 40 (45%) patients, dysphagia in the 3rd week in 41 (47%) patients, xerostomia in the 3rd week in 33 (38%) patients, and dermatitis at week 6 in 24 (27%) patients. Conclusions: Patients with head and neck cancer who undergo radiotherapy from week 1 to week 7 will experience side effects, including mucositis, dysphagia, xerostomia, and dermatitis. The average side effect appears in the 3rd week with grade 1.

Investigating and Analyzing Prognostic Factors and Their Impact on Recurrent Cervical Cancers.

The incidence of cervical cancer in Indiais significantly high, and the average recurrence age is much less. The standard line of treatment consists of concurrent chemoradiotherapy. If a recurrence occurs, the treatment options or set of interventions are limited and suboptimal. Through this review, we have analyzed and classified the possible prognostic factors for cervical cancer into three broad categories, viz., (a) disease-related factors, (b) patient-related factors, and (c) treatment-related factors. Disease-related factors include tumor histology, tumor size, stage, parametrial involvement (PMI), Prognostic Nutritional Index (PNI), lymphovascular space invasion (LVSI), and nodal status. Patient-related factors include overall treatment time (OTT), nutritional status, hemoglobin level, comorbidities, and age. Treatment-related factors include addition of chemotherapy, techniques of external beam radiotherapy (EBRT), techniques of brachytherapy, and quality assurance for radiation therapy delivery. Out of these, extremely significant prognostic factors were tumor size and stage, nodal status, PMI, nutritional status, and addition of chemotherapy. Impactful factors include younger age, histology, LVSI, associated comorbidities, hemoglobin level, OTT, and patient-specific quality assurance. The factor that is not related or significant is the technique used for EBRT and brachytherapy delivery.

Dose and DNA damage modelling of diffusing alpha-emitters radiation therapy using Geant4

Purpose:Diffusing alpha-emitters radiation therapy (DaRT) is a brachytherapy technique using α-particles to treat solid tumours. The high linear energy transfer (LET) and short range of α-particles make them good candidates for the targeted treatment of cancer. Treatment planning of DaRT requires a good understanding of the dose from α-particles and the other particles released in the 224Ra decay chain. Methods:The Geant4 Monte Carlo toolkit has been used to simulate a DaRT seed to better understand the dose contribution from all particles and simulate the DNA damage due to this treatment. Results:Close to the seed α-particles deliver the majority of dose, however at radial distances greater than 4 mm, the contribution of β-particles is greater. The RBE has been estimated as a function of number of double strand breaks (DSBs) and complex DSBs. A maximum seed spacing of 5.5 mm and 6.5 mm was found to deliver at least 20 Gy RBE weighted dose between the seeds for RBEDSB and RBEcDSB respectively. Conclusions:The DNA damage changes with radial distance from the seed and has been found to become less complex with distance, which is potentially easier for the cell to repair. Close to the seed α-particles contribute the majority of dose, however the contribution from other particles cannot be neglected and may influence the choice of seed spacing.

A diffusion-leakage model coupled with dose point kernels (DPK) for dosimetry of diffusing alpha-emitters radiation therapy (DaRT).

Diffusing alpha-emitters radiation therapy (DaRT) is a novel brachytherapy technique that leverages the diffusive flow of 224Ra progeny within the tumor volume over the course of the treatment. Cell killing is achieved by the emitted alpha particles that have a short range in tissue and high linear energy transfer. The current proposed absorbed dose calculation method for DaRT is based on a diffusion-leakage (DL) model that neglects absorbed dose from beta particles. This work aimed to couple the DL model with dose point kernels (DPKs) to account for dose from beta particles as well as to consider the non-local deposition of energy. The DaRT seed was modeled using COMSOL multiphysics and the DL model was implemented to extract the spatial information of the diffusing daughters. Using Monte-Carlo (MC) methods, DPKs were generated for 212Pb, 212Bi, and their progenies since they were considered to be the dominant beta emitters in the 224Ra radioactive decay chain. A convolution operation was performed between the integrated number densities of the diffusing daughters and DPKs to calculate the total absorbed dose over a 30-day treatment period. Both high-diffusion and low-diffusion cases were considered. The calculated DPKs showed non-negligible energy deposition over several millimeters from the source location. An absorbed dose>10Gy was deposited within a 1.8mm radial distance for the low diffusion case and a 2.2mm radial distance for the high diffusion case. When the DPK method was compared with the local energy deposition method that solely considered dose from alpha particles, differences above 1Gy were found within 1.3 and 1.8mm radial distances from the surface of the source for the low diffusion and high diffusion cases, respectively. The proposed method enhances the accuracy of the dose calculation method used for the DaRT technique.

1556: Interstitial, surface and combined techniques of high dose rate brachytherapy for lip cancer

1556: Interstitial, surface and combined techniques of high dose rate brachytherapy for lip cancer

2811: Two brachytherapy techniques for the management of lower third vaginal involvement in cervix cancer

2811: Two brachytherapy techniques for the management of lower third vaginal involvement in cervix cancer

Advances in Head-and-Neck Interventional Radiotherapy (Brachytherapy)

Interventional radiotherapy, also known as brachytherapy, is the use of sealed radioactive sources that directly deliver radiation to the tumor or tumor bed. Its unique dose distribution profile allows for high conformality, making it a very useful modality in the treatment of cancers in the head and neck, where different organs and substructures that serve various but related functions are situated close to each other. In recent years, we have seen several important technological breakthroughs in the field, especially regarding its application in head and neck cancers. These include advances in treatment delivery, dosimetry planning , image guidance , and catheter positioning techniques . These innovations, which often require interdisciplinary interventions, have resulted in enhanced treatment accuracy, and therefore, major clinical advantages in terms of increased local control and decreased toxicity, as well as economic benefits. In order to highlight the differences from old brachytherapy techniques, a more appropriate terminology should perhaps be adopted, to signify these advancements that resulted in new opportunities, approaches and better outcomes – interventional radiotherapy (IRT). Such a change in terminology will not only allow recognition of these advances, but also a meaningful distinction from obsolete techniques and suboptimal outcomes that are associated with traditional brachytherapy. This is very important in increasing awareness among professionals outside the field of radiation oncology. We briefly review these recent advances, the current indications, and future directions for IRT in head-and-neck cancers. Keywords : interventional radiotherapy, brachytherapy, head-and-neck cancers, image-guidance

Development of learning-based online C-arm CT imaging technique for image-guided adaptive brachytherapy

Existing protocols for image-guided adaptive brachytherapy (BT) pose distinct limitations, which include: (1) the possible misalignment of the application position as a consequence of patient translocation between the treatment room and the computed tomography (CT)/magnetic resonance imaging (MRI) suite, (2) an inherent inability to continually monitor physiological and anatomical changes during the course of 3–10 fraction treatment regimens, and (3) insufficient tracing of the radioactive source movement within the patient's body. In response to these challenges, this study proposes an innovative deep-learning-based C-arm CT/SPECT imaging system tailored specifically for image-guided adaptive BT. This technological advancement aims to enable the execution of high-precision online adaptive BT, thereby amplifying the adaptability and effectiveness of oncological care. An image dataset of 66 non-contrast pelvic CT studies was acquired and limited-angle cone-beam CT (CBCT) images were generated by mathematically calculating sinograms for voxel phantoms based on these CT images. Using a Generative Adversarial Network (GAN), low-quality CBCT images obtained using a 110° limited-angle rotating C-arm system were transformed into high-quality diagnostic CT images. The performances of these networks were evaluated by comparing them with CBCT images reconstructed using an iterative reconstruction method and ground-truth images. Synthetic CT images were successfully transformed from low-quality CBCT images, considerably reducing streaking artifacts and preserving the anatomical structures. Our deep-learning-based image reconstruction technique could successfully improve the image quality of limited-angle CBCT, similar to the ground-truth image quality, with a faster speed than the latest iterative reconstruction algorithm. We expect that this will be effectively implemented in online image-guided adaptive BT and patient dose verification.

Salvage high-dose rate brachytherapy for local recurrence of prostate cancer after radical prostatectomy

Background. The current need for optimization of salvage treatment methods is dictated by the growing expansion of indications for radical prostatectomy in many centers in the developed countries of the world.Aim. To evaluate the effectiveness, toxicity, and technical characteristics of high-dose rate brachytherapy in treatment of local prostate cancer (PCa) recurrences after radical prostatectomy.Materials and methods. Between January 2015 and December 2020, salvage high-dose rate brachytherapy was performed in 17 patients at the Russian Scientific Center of Roentgenology and Radiology for local recurrence of PCa after radical prostatectomy. All patients underwent multiparametric magnetic resonance imaging of the pelvis at the stage of primary diagnosis in order to determine macroscopic tissue component in the prostate bed area. To rule out regional and distant metastases, all patients underwent positron emission tomography with 18F- or 68Ga-labeled prostate-specific membrane antigen. All patients included in the study underwent perineal biopsy of the prostate bed and seminal vesicles.Results. Median follow-up in the treatment group was 35.7 (24–54) months. Overall survival was 100 %. Prostatespecific antigen-specific survival was 88.2 %. There were no local recurrences of PCa in the treatment group. In patients with local PCa recurrence, significant predictors of treatment failure were the presence of clinically extremely high risk of progression at initial diagnosis (p = 0.003), development of biochemical relapse up to 24 months after main treatment (p = 0.001), and increased blood level of prostate-specific antigen above 10 ng/mL during registration of biochemical relapse (p = 0.002).Conclusion. High-dose rate brachytherapy is a safe and effective salvage treatment for local recurrence of PCa after radical prostatectomy. In addition to the brachytherapy technique, the diagnostic stage is also of great importance providing visualization of the exact location of tumor recurrence.

Disinsert, retract and rotate technique of plaque brachytherapy.

Plaque brachytherapy is commonly used in the management of choroidal melanomas. The surgical steps usually involve creating a conjunctival peritomy, fixing the recti muscles, with or without disinserting them based on the location of the lesion, and placing the plaque. The inferior oblique muscle is attached close to the macula, and in cases of perimacular or peripapillary lesions, the muscle needs to be sacrificed. The authors here demonstrate a novel technique of placing radioactive plaque without disinserting the inferior oblique muscle in cases of perimacular or peripapillary choroidal melanomas. The video demonstrates how the "disinsert, retract, and rotate technique" of brachytherapy plaque placement can be performed and what are the fundamentals behind this technique. The authors have performed this procedure multiple times and there has been no incidence of plaque tilt or migration. In perimacular and peripapillary choroidal melanoma brachytherapy plaque placement, the inferior oblique muscle can be spared. The simple technique does not lead to any tilt or migration of the radioactive plaque. https://youtu.be/YMIg3rYyp2o.

Post- versus intra-operative implant for breast cancer interstitial brachytherapy: How to choose?

Breast brachytherapy (BB) represents an important radiation therapy modality in modern breast cancer treatments. Currently, BB is mainly used for accelerated partial breast irradiation (APBI), local boost after whole breast radiation therapy (WBRT), and as salvage re-irradiation after second lumpectomy (APBrl). Two multi-catheter interstitial brachytherapy (MIB) techniques can be offered: intra-operative (IOB) and post-operative (POB) brachytherapy. The aim of this article was to summarize current available data on these two different brachytherapy approaches for breast cancer. A literature search was performed, and different experiences published by BB expert teams were analyzed and compared. These two different brachytherapy approaches for breast cancer have also been presented and discussed during meetings of the GEC-ESTRO BCWG. In addition, expert recommendations were defined. A comprehensive description and practical comparison of both the techniques, i.e., IOB and POB, considering the latest available published data were presented. Different technical, logistic, and clinical aspects of both the methods were thoroughly examined and analyzed. This detailed comparison of the two breast brachytherapy techniques was supported by scientific data from extensive experience of experts, facilitating an objective analysis that, to our knowledge, has not been previously published. Based on the comprehensive analysis of both the brachytherapy techniques available, this article serves as a valuable resource to guide breast teams in selecting the optimal BB technique (POB or IOB), considering hospital environment, multi-disciplinary collaboration, and patient logistics.

Dosimetric comparison of intra-cavitary brachytherapy technique with free-hand (intra-cavitary + interstitial) technique in cervical cancer.

The aim of the study was to dosimetrically compare intra-cavitary brachytherapy technique (ICBT) with free-hand (intra-cavitary + interstitial, IC + IS) technique. Twenty seven locally advanced carcinoma cervix patients were included in the study. Patients with more than medial 1/3rd parametrial residual disease without extending upto lateral pelvic wall were included, following external beam radiotherapy (EBRT), in which cobalt-60 high-dose-rate (60Co HDR) brachytherapy source was used. Dose for both plans were 6.5 Gy × 4 fractions, 2 fractions per day, 6 hours apart, over 2 days. Free-hand brachytherapy technique, consisted of placement of central tandem and 2 ovoids along with needles without using template, was applied. Two plans were generated by activating and deactivating the needles, and compared by normalizing to V100. A total of 79 needles were applied. Using paired-t test, dosimetric comparison of both the plans was done. Free-hand plan had a significant higher mean V90 (volume receiving 90% of the dose) of 94.2% compared with 87.22% in ICBT plan (p ≤ 0.0001). Free-hand and ICBT plans presented a mean V100 values of 89.06% and 81.51% (p ≤ 0.0001), respectively, favoring free-hand plan. The mean D90 (dose to 90% volume), D98, and D100 of free-hand plan were 6.28 Gray (Gy), 4.91 Gy, and 3.62 Gy, respectively, but equivalent parameters in ICBT plan were 5.26 Gy, 3.72 Gy, and 2.61 Gy, with p value ≤ 0.0001. In both the plans, D2cc of the bladder, rectum, and sigmoid were 4.59 Gy, 3.98 Gy, 2.77 Gy, and 4.46 Gy, 3.90 Gy, 2.67 Gy, respectively, with no statistical significance. Free-hand brachytherapy (IC + IS) achieves a statistically significant better dose distribution to high-risk clinical target volume (HR-CTV) comparing with ICBT technique with similar dose to organs at risk.

Patient Experiences of Brachytherapy for Locally Advanced Cervical Cancer: Hearing the Patient Voice Through Qualitative Interviews

BackgroundBrachytherapy for gynaecological cancer is reported to cause pain, anxiety and distress with no clear guidance for optimising patient experiences. The aim of this study was to explore patient experiences of brachytherapy and views on improvements. Materials and MethodsSemi-structured interviews were undertaken with patients who had received brachytherapy for locally advanced cervical cancer. Two cohorts were recruited: cohort one had recently had brachytherapy, cohort two were a year post brachytherapy. Four recruitment sites were selected, where brachytherapy is given in different ways, some with short day case procedures and others having one or two overnight stays with applicators in place. Consecutive patients were invited to interview. Participants were asked to retell their brachytherapy story, with views on their care and ideas for improvement. Interviews were audio-recorded, transcribed and data analysed following Braun and Clarke's method for reflexive thematic analysis.16 ResultsThirty five interviews were conducted (20 in cohort one and 15 in cohort two). Participant's ages ranged from 28 to 87 years. The interview duration ranged from 22 to 78 minutes. Difficult and traumatic experiences were reported, including periods of severe pain and perceptions of poor care. However, some participants described positive experiences and what went well.Three themes were developed: 1) How I got through it 2) Unpleasantness, discomfort and the aftermath 3) Emotional consequences and traumaSome aspects of medium and long duration brachytherapy were found to be more problematic compared with short duration brachytherapy. Exploring experiences at one year post brachytherapy has provided insights into the long-lasting impact of brachytherapy experiences. ConclusionHearing the patient voice has demonstrated that further work is needed to improve patient care in modern brachytherapy techniques using different regimes and durations, to minimise difficult and traumatic patient experiences. Study insights will inform future work to develop clinical care recommendations.

Phase II Trial of Five-Fraction Accelerated Partial Breast Irradiation Using Noninvasive Image-Guided Breast Brachytherapy

NIBB has potential advantages over other APBI techniques by delivering highly conformal radiation with minimal collateral dose to the heart and lung compared with external beam techniques, but unlike other brachytherapy techniques NIBB is non-invasive. Previous data has shown encouraging outcomes using a 10-fraction regimen. To improve efficiency, convenience, and cost, reduction in the fraction number is desirable. Final results of a prospective phase II trial are reported. NIBB APBI was delivered using 28.5Gy in 5 fractions daily over 1 week. Patient eligibility criteria required: invasive carcinoma ≤2.0 cm or DCIS ≤3.0 cm, ER positive (if invasive), lymph node negative, LVI absent, and lumpectomy with margins negative by 2mm. The primary endpoint was grade ≥ 2 subcutaneous fibrosis/induration <30%. Secondary endpoints included any late toxicity, cosmetic outcome, and local control. 40 patients were treated with a median follow-up of 59.7 months. The mean age was 67 years (50-89 years) and tumor size was 1.0cm (0.3-2.0cm). 80% had invasive carcinoma. The mean breast separation with compression was 6.7cm (3.5-8.9cm). The 5-year actuarial local control was 96.6% and overall survival was 96.9%. Grade 2 and 3 late toxicities were 15% and 0%, respectively. The rate of grade 2 subcutaneous fibrosis/induration was 2.5% (+/-2.5%) meeting the study's primary endpoint. The most common late toxicity of any grade was skin telangiectasia; 22.5% grade 1 and 15% grade 2. Only breast separation was associated with telangiectasia risk, p=0.002. Overall cosmetic outcome was excellent, good, and fair/poor in 75%, 25%, and 0%, respectively. NIBB APBI delivered in 5 fractions results in a low rate of late toxicity and a high rate of good/excellent cosmetic outcomes. Telangiectasia risk can be minimized by keeping breast separation ≤7.0cm. The local failure rate was appropriately low. Further investigation of this technique is warranted.

Dosimetric comparison of postoperative interstitial high-dose-rate brachytherapy and modern external beam radiotherapy modalities in tongue and floor of the mouth tumours in terms of doses to critical organs.

The aim of the study was to dosimetrically compare interstitial high-dose-rate (HDR) brachytherapy (BT) and modern external beam radiotherapy modalities, as volumetric modulated arc therapy (VMAT) and stereotactic radiotherapy with Cyberknife (CK) of tumours of the tongue and floor of the mouth in terms of dose to the critical organs. In National Institute of Oncology, Budapest, between March 2013 and August 2022 twenty patients (11 male/9 female) with stage T1-3N0M0 tongue (n = 14) and floor of mouth (n = 6) tumours received postoperative radiotherapy because of close/positive surgical margin and/or lymphovascular and/or perineural invasion. High-dose-rate interstitial brachytherapy applying flexible plastic catheters with a total dose of 15 × 3 Gy was used for treatment. In addition to BT plans VMAT and stereotactic CK plans were also made in all cases, using the same fractionation scheme and dose prescription. As for the organs at risk, the doses to the mandible, the ipsilateral and the contralateral salivary glands were compared. The mean volume of the planning target volume (PTV) was 12.5 cm3, 26.5 cm3 and 17.5 cm3 in BT, VMAT and CK techniques, respectively, due to different safety margin protocols. The dose to the mandible was the most favourable with BT, as for the salivary glands (parotid and submandibular) the CK technique resulted in the lowest dose. The highest dose to the critical organs was observed with the VMAT technique. The mean values of D2cm3 and D0.1cm3 for the critical organs were as follows for BT, VMAT and CK plans: 47.4% and 73.9%, 92.2% and 101.8%, 68.4% and 92.3% for the mandible, 4.8% and 6.7%, 7.3% and 13.8%, 2.3% and 5.1% for the ipsilateral parotid gland, 3.5% and 4.9%, 6.8% and 10.9%, 1.5% and 3.3% for the contralateral parotid gland, 7.3% and 9.4%, 9.0% and 14.3%, 3.6% and 5.6% for the contralateral submandibular gland. The present results confirm that BT, despite being an invasive technique, is dosimetrically clearly beneficial in the treatment of oral cavity tumours and is a modality worth considering when applying radiotherapy, not only as definitive treatment, but also postoperatively. The use of the CK in the head and neck region requires further investigation.

Dosimetric Investigation of Interstitial Versus Combined Interstitial with Intracavitary High Dose Rate Brachytherapy for Cervical Cancer

The purpose of the study was to evaluate clinical target (HR-CTV) coverage and OAR doses of ISBT and IS-ICBT brachytherapy techniques for cervix cancer. As this is a retrospective study, 11 patients treated from 2018 to 2022 were identified, ISBT (n=4) and IC-ISBT (n=7). Dose-volume histogram (DVH) from Oncentra Treatment Planning System and dosimetric parameters were analyzed and evaluated.The results showed the mean EQD2 of HR-CTV for both techniques were 89.1 ± 11.71 Gy while the mean EQD2 of D2cc for bladder, rectum and sigmoid were 88.9 ± 16.71 Gy, 81.2 ± 12.63 Gy, and 70.1 ± 15.95 Gy, respectively. For IC-ISBT technique, the mean EQD2 of HR-CTV was 91.5 ± 8.4 Gy which was slightly exceeds the dose constraints of 80 to 90 Gy based on ABS recommendation. HR-CTV volume that ranged from 34.93 - 168.33 cm3. The mean of CI was 0.90 and the mean of DHI for this technique was 0.36 ± 0.06. Meanwhile for ISBT technique, the mean HR-CTV volume range from 26.95 - 82.82 cm3. The mean EQD2 of HR-CTV was at 85.1 ± 16.75. The mean CI and DHI were at 0.85 ± 0.16 and 0.37 ± 0.1, respectively. As a conclusion, the mean EQD2 doses to the rectum (81.2 Gy) in both techniques slightly exceeded the limit from ABS recommendation. The mean DHI value was not quite significant different in both techniques. However, the IS-ICBT technique was more superior in conforming dose to HR-CTV based on higher CI value compared to ISBT alone.

Impact of Race and Socioeconomic Factors on Clinical Outcomes in Cervical and Endometrial Cancer Patients Treated with Brachytherapy

Racial and socioeconomic disparities impact cancer care and outcomes. This project aimed to evaluate relationship between race and socioeconomic factors and clinical outcomes in patients with cervical and endometrial cancer. All cervical and endometrial cancer patients treated with brachytherapy at our institution from 2007-2017 were identified. Race, insurance status, employment status, disability status, and distance from brachytherapy center were recorded. Clinical characteristics including stage at presentation, number of involved nodes, histology, and brachytherapy technique (cervical cancer only) were recorded. PFS and OS were calculated from date of last brachytherapy fraction, with censorship at date of last follow-up. Correlation was tested between race and socioeconomic factors and PFS and OS using Cox regression models. Association with other outcomes was examined with Wilcoxon rank sum tests, Fisher's exact tests, and Spearman's rank correlation coefficients. A total of 251 cervical and 130 endometrial cancer patients were identified, with median follow-up 5.2 years and 4.8 years, respectively. For cervical cancer, UVA showed significant correlation for PFS and OS with race, insurance status, employment status, and disability status. For endometrial cancer, UVA showed significant correlation for PFS with race, insurance status, and disability status, and for OS with race and insurance status. For cervical cancer, MVA showed significantly improved PFS in patients with insurance (p < 0.001) and patients who were employed (p = 0.002), and significantly improved OS in patients who were white (p = 0.039), patients with insurance (p<0.001), and patients who were employed (p-0.001). For endometrial cancer, MVA showed significantly improved PFS and OS in patients who were white (p = 0.003 and p = 0.005, respectively) and patients with insurance (p = 0.027 and p = 0.002, respectively). For cervical cancer, there was no correlation between insurance or employment status and stage. For endometrial cancer, there was no correlation between race or insurance status and stage. For cervical cancer, insurance and employment status are significant predictors of PFS and OS, and race is additionally a significant predictor of OS. For endometrial cancer, race and insurance status are significant predictors of PFS and OS.

Investigating the Relationship between the Dose to the Recto-Vaginal Reference Point and Vaginal Stenosis among Cervical Cancer Patients Treated at a North American Academic Institution

In the treatment of locally advanced cervical cancer (LACC) with image-guided brachytherapy, there are limited data concerning the optimal vaginal dose constraints to minimize risk of vaginal stenosis (VS). While the dose to the recto-vaginal reference point (RV-RP) has been reported to be associated with VS, the EMBRACE dose constraint of 65Gy is a higher value than we typically measure at our institution. We hypothesize that there may be an association between the dose to the RV-RP and VS at lower values than previously reported. Following IRB approval, data were collected for 87 LACC patients treated at a single institution between 12/2012 - 4/2022 with available CTCAEv4.0 VS scores and minimum follow-up of 4 months. Only patients treated with tandem/ring or tandem/ovoid applicators, with or without interstitial needles, were included. Perineal template and cylinder-based applications were excluded. Dose to the RV-RP was retrieved from the treatment planning system. Primary endpoint was grade 2 or higher (G ≥ 2) VS. The Kaplan-Meier method was used to estimate the cumulative incidence of VS. The log-rank test and multivariable Cox proportional-hazards regression were used to evaluate the association between dose to the RV-RP with VS G ≥ 2. The cohort median age was 48 (IQR 38-61). 59 patients (68%) were stage I or II (FIGO 2009) and 28 (32%) were stage III. Ethnicity was Hispanic or Latino in 20 patients (23%). Technique was predominantly tandem/ring (78%), high-dose-rate (79%), and intracavitary without interstitial needles (83%). The most common dose-fractionation was 28Gy in 4 fractions (following 45Gy to the pelvis). The median cumulative HR-CTV D90% dose was 83.1Gy (IQR 79.7 - 86.5). Median dose to the RV-RP was 51.1Gy (IQR 49.2 - 55.8). Only 9 patients (10%) had a dose to the RV-RP higher than 65Gy (max 71.1). Median follow-up was 22.6 months (range: 4.2 - 114). The 2-year incidence of VS G ≥ 2 was 24.4%. Dose to the RV-RP was associated with VS G ≥ 2. The 2-year incidence of VS G ≥ 2 for patients with RV-RP dose <51 vs ≥51Gy was 13.1% vs 34.6% (p = 0.038). On multivariable regression, dose to the RV-RP ≥51Gy (HR 2.94 CI 1.16 -7.48, p = 0.024), Hispanic or Latino ethnicity (HR 3.71 CI 1.38 - 9.99, p = 0.01), and stage III (HR 2.33 CI 1.06 - 5.12, p = 0.035) were significantly associated with increased risk of VS G ≥ 2. We observed a statistically significant association between the dose to the RV-RP and VS G ≥ 2, when stratified by our median dose to the RV-RP of 51Gy, which is lower than the dose constraint of 65Gy previously reported by EMBRACE. These findings may be partially explained by differences in patient demographics or brachytherapy technique. Further investigation of the relationship between the dose to the RV-RP and development of VS G ≥ 2 across broader populations is warranted.

Very APBI in 1 or 2 Days: Late Toxicity and Early Oncological Outcomes of the GEC-ESTRO Cohort

To analyze late toxicity after very accelerated partial breast irradiation (VAPBI) for low-risk breast cancer. In this retrospective observational international multicenter study (HDH F20220713143949) from 7 European centers, patients with low-risk breast cancer underwent lumpectomy + adjuvant VAPBI based on high-dose rate (HDR) multicatheter interstitial brachytherapy (MIB). VAPBI was performed with 4 (4 × 6.2 Gy/2 d), 3 (3 × 7.45 Gy/2 d) or 1 fraction (1 × 16 Gy or 1 × 18 Gy/1 d). Primary endpoint was late toxicity. Secondary endpoints were oncological outcome based on cumulative incidence of breast cancer local relapse (LR) and distant metastasis disease (DMD) and cause-specific (CSS) and overall (OS) survival. Prognostic factors for late toxicity were analyzed. From 01/2012 to 06/2022, the GEC-ESTRO VAPBI cohort included 516 pts with an early breast cancer. Median follow-up was 42 months [95% CI = 39 - 44]. Median age was 71 years [40 - 100]. Median tumor size was 12 mm [1 - 46]. Tumor was mainly invasive ductal carcinoma (78%), pN0 (88.5%), with positive hormonal receptors (98.5%) and negative HER2 overexpression (96%). Patients underwent hormonal and chemo-therapy in 93.8% and 2.3% respectively. Catheter placement was performed peri or post-operatively in 50.2% and 49.8% respectively. Median time interval between surgery and VABPI was 10 days [6 - 65]. VAPBI delivered 1, 3 and 4 fractions for 205 pts (39.7%), 167 pts (32.4%) and 144 pts (28%) respectively. Median CTV was 40.7 cc [95% CI = 26.6 - 72], median V100%, V150%, D90% and Dose non-uniformity ratio (DNR) were 90.2% [95% CI = 84.1 - 97.2], 24.2% [95% CI = 18.9 - 31.6], 103.8% [95% CI = 100.1 - 107.4] and 0.28 [95% CI = 0.23 - 0.33] respectively, 211 late toxicity events were observed in 168 pts (32.6%). Fibrosis, dyschromia, pain and telangiectasia were observed in 26.7%, 7.9%, 7.2% and 0.4 respectively. Grade 2 and 3 late toxicities were observed in 7.2 and 0.6% respectively (no G4). Grade ≥2 late toxicity was observed in 8.1%, 16.7% and 3.7% after 1, 3 and 4 fractions, respectively (p = 0.004). CTV > 50 cc (p = 0.007) and V150 > 40% (p = 0.027) were prognostic factors for G≥2 late toxicity. Regarding oncological outcome, 4-year cumulative incidence of LR, RR and DMD were 2% [95% CI = 0 - 3], 1% [95% CI = 0 - 2] and 1% [95% CI = 0 - 2] respectively. CSS and OS were 98% [95% CI = 96 - 100] and 93% [95% CI = 90 - 96] respectively. No significant difference was observed in terms of oncological outcome between the 3-fractionation groups. VAPBI based on 1 or 2 days of HDR MIB represents an attractive de-escalation irradiation approach for low-risk breast cancer. Late toxicity profile appears acceptable while early oncological outcome shows excellent local control. Brachytherapy technique remains a key component of clinical outcome. Longer follow-up is warranted in order to confirm these encouraging preliminary results.

Utilizing a novel hybrid brachytherapy technique FINITO (Freehand Interstitial Needles in addition to Tandem and Ovoid) for locally advanced cervical cancer

PURPOSEWe aimed to assess the clinical feasibility and advantages of using a novel hybrid brachytherapy technique by placing Freehand Interstitial Needles in addition to the Tandem and Ovoid applicator (FINITO) for the treatment of locally advanced cervical cancer (LAC). METHODS AND MATERIALSA retrospective analysis was performed on two cohorts of patients with LACC treated at our institution: 29 patients in the FINITO group and 17 patients in the control group using T&O only approach. Clinical outcomes of interest included local control (LC), progression-free survival (PFS), overall survival (OS), and rates of acute and late toxicities. Kaplan–Meier methodology was used to estimate OS, PFS, and LC. Wilcoxon signed-rank test was used to compare the median values for dosimetry parameters. A p-value of ≤ 0.05 was considered statistically significant. All statistical analyses were performed using RStudio. RESULTSAt a median of 2 years there was no difference in rates of OS, PFS or LC between the FINITO and the control group of patients. The 2-year OS, PFS, and LC for the FINITO group were 59% (95% CI 34%–100%), 58% (95% CI 38%–89%), and 84% (95% CI 69%–100%), respectively. Late toxicities were significantly lower in the FINITO group for both gastrointestinal and genitourinary symptoms (p = 0.001 and 0.01, respectively) as compared to the T&O group. CONCLUSIONBased on the equivalent LC rate and lower toxicity profile, our FINITO technique appears to be an excellent alternative to the standard intracavitary brachytherapy in patients with advanced disease, especially in resource-limited settings.