Multicatheter Interstitial Brachytherapy Research Articles

Thursday, July 11, 20244:00 PM - 5:30 PM BP01 Presentation Time: 4:00 PM: Accelerated Partial Breast Irradiation Using Sole Interstitial Multicatheter Brachytherapy - GEC-ESTRO Phase 3 Trial: 10-year Results in Context of Current ASTRO and GEC-ESTRO Patient Selection Criteria

Thursday, July 11, 20244:00 PM - 5:30 PM BP01 Presentation Time: 4:00 PM: Accelerated Partial Breast Irradiation Using Sole Interstitial Multicatheter Brachytherapy - GEC-ESTRO Phase 3 Trial: 10-year Results in Context of Current ASTRO and GEC-ESTRO Patient Selection Criteria

Five-year results of the very accelerated partial breast irradiation VAPBI phase I-II GEC-ESTRO trial

Background and purposeThe standard partial breast postoperative treatment for early breast carcinomas with multi-catheter interstitial brachytherapy (MIBT) requires 7–8 fractions in 4–5 days as used in the APBI GEC-ESTRO phase III trial. In 2017 the GEC-ESTRO Breast Cancer Working Group started a Phase I-II trial to study if very accelerated partial breast irradiation (VAPBI) using 3–4 fractions could be equivalent. Material81 patients with low-risk invasive carcinomas underwent high dose rate MIBT. Mean age was 68 (51–90); 33 women received 4 fractions of 6.25 Gy in 2–3 days, and 48 subsequent patients 3 fractions of 7.45 Gy in 2 days, 36 perioperatively and 45 postoperatively. ResultsMedian follow-up was 62 months, with 5-year actuarial breast recurrence of 3.4 % (two cases). One patient died due to metastasis. Pigmentation changes in the entrance of tubes remained visible only in 12.3 % in long term (skin G1 toxicity). Fibrosis or slight induration (G1) in 22.2 % and G2 in 9.9 %. No case of telangiectasia has been described. Cosmetic outcome is good or excellent in 95 % and fair in 5 %. Four tumors located in the retroareolar area showed nipple retraction. ConclusionVAPBI with MIBT using four fractions of 6.25 Gy or three fractions of 7.45 Gy in two or three days offers good local control, with a 5-year rate of fibrosis G2 similar to the GEC ESTRO phase III trial. VAPBI in two days is a good choice to decrease the total time of treatment, which is beneficial for the patient and reduces the workload.

Ten-Year Results of Accelerated Partial-Breast Irradiation with Interstitial Multicatheter Brachytherapy after Breast-Conserving Surgery for Low-Risk Early Breast Cancer.

Patients with an early carcinoma of the breast are commonly treated by breast-conserving surgery (BCS) and postoperative radiotherapy. Partial-breast irradiation has gained acceptance in the last few years. Between December 2008 and December 2017, 182 low-risk breast cancer patients treated by BCS in the four university hospitals of the province of Las Palmas and treated with APBI using interstitial multicatheter brachytherapy were included in this study. After a mean follow-up for survivors of 10 years, the treatment was shown to be safe, as no severe acute/late toxicity (grade ≥ 3) was observed. The 10-year IBTR was 1.7% (95%CI: 0.7-2.7%), and the cause-specific survival was 94.9% (95%CI: 93.2-96.6%). We suggest that multicatheter brachytherapy after BCS is safe and effective in early breast cancer patients.

Preliminary report on ultrashort perioperative partial-breast irradiation with multicatheter interstitial brachytherapy for early-stage breast cancer.

Perioperative partial-breast irradiation (PBI) with multicatheter interstitial brachytherapy (MIB) is less invasive and more convenient than postoperative one. This study aimed to compare ultrashort perioperative MIB-PBI (uPBI) and conventional perioperative MIB-PBI (cPBI) performed during the same period of time. Inclusion criteria of the study were patients aged ≥ 40years and those with T0-2 (≤ 3cm), N0-mi, and negative margins on mammography. The locoregional recurrence (LRR) and toxicity rates were compared between uPBI at a dose of 25.2Gy in four fractions and cPBI at a dose of 32Gy in eight fractions. In total, 198 patients (151 with uPBI and 47 with cPBI) were evaluated. At a median follow-up of 20.1months, one (0.66%) patient in the uPBI group had LRR. The 2-year ipsilateral breast tumor recurrence-free survival rates of the uPBI and cPBI groups were 98.7% and 100%, respectively. The highest toxicity grades were grade 1 in 23 (15.2%) and grade 2 in 2 (1.3%) patients in the uPBI group, and grade 1 in 8 (17.0%) and grade 2 in 1 (2.1%) patient in the cPBI group. None of the patients in the two groups presented with grade 3 and higher toxicities. The toxicity rates between the two groups did not significantly differ. Further, 22 (14.6%) patients in the uPBI group and 8 (17.0%) in the cPBI group, and 3 (2.0%) patients in the uPBI group and 1 (2.1%) in the cPBI had acute and late toxicities, respectively. The timing of toxicity development between the two groups did not significantly differ. Although this preliminary report included a small sample size and had a short follow-up period, the local control and toxicity rates were similar between the uPBI and cPBI groups. Further research is warranted to investigate the ideal dose schedule of MIB-PBI.

Indian Brachytherapy Society consensus recommendations for brachytherapy in breast cancer.

This consensus statement of Indian Brachytherapy Society (IBS) aims to generate practical and reproducible guidelines allowing for direct implementation in the Indian scenario. IBS board of directors appointed a panel of physicians with expertise in breast cancer and, in particular, breast brachytherapy, to develop a consensus statement. First, a literature review on breast brachytherapy was conducted, focusing on randomized trials, prospective studies, and multi-institutional series. Then, guidelines were drafted based on authors' consensus according to Indian scenario. IBS advocate accelerated partial breast irradiation (APBI) with brachytherapy following breast conservation surgery (BCS) for suitable groups of patients. Also, IBS recommends brachytherapy as the preferred technique for patients requiring tumor bed boost. Multi-catheter interstitial brachytherapy (MIB) is suitable in most situations, except for a large tumor to breast ratio, and type 2 oncoplasty or higher performed. For best cosmesis, IBS recommends a minimum 3-week gap between chemotherapy and APBI. Brachytherapy continues to be an established technique for APBI as well as boost in appropriately selected patients with early breast cancer (EBC). As breast brachytherapy is an underutilized therapy in the Indian context, this article will hopefully encourage the readers to use its clinical potential in the suitable groups of patients.

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.

Analysis of multicatheter interstitial brachytherapy: Accelerated partial breast irradiation in a retrospective cohort of early-stage breast cancer patients

To determine cardiac dose received by patients treated with high dose rate interstitial brachytherapy. Patients with early-stage, node negative breast cancer can be treated using multi-catheter interstitial brachytherapy accelerated partial breast irradiation (MIB-APBI), with the benefit of reduced treatment volumes and favorable toxicity. We conducted a retrospective review of left-sided breast cancer patients treated using MIB-APBI at our institution since 2014. The mean heart dose (MHD) was calculated using the Oncentra 3.2 planning system. The minimum distance between the planning target volume (PTVeval) and heart contour was measured manually. 81 patients were included. The upper outer quadrant was the most common site. The MHD was 97.8 cGy (EQD2a/b=2) (range 22-229 cGy). MHD significantly correlated with the closest distance between PTVeval and heart contour (correlation coefficient -0.823, p <0.001); size of PTVeval (cc) and quadrant location did not. Appropriately selected women with early-stage, low-risk, left-sided breast cancer who received MIB-APBI had acceptable MHD. There was a strong correlation between the distance of PTVeval and MHD. Quadrant breast tumor is in cannot be used as a surrogate for MHD in brachytherapy. Our findings contribute to the growing evidence of the utility and safety of MIB-APBI.

Prospective Cohort Study to Evaluate Toxicity and Cosmesis between Interstitial APBI and Ultra-Hypo-Fractionated Whole Breast Irradiation in Patients with Early Breast Cancer

Both interstitial multi-catheter brachytherapy based accelerated partial breast irradiation (APBI) and ultra-hypo-fractionated whole breast irradiation (WBI) with 5 fractions can complete treatment in a short time and result in lower treatment-related costs. Although data are available on their toxicity compared with conventional and hypo-fractionated regimens, there are few data directly comparing these two techniques. This prospective cohort study enrolled early breast cancer patients with negative ink margin, T1 or T2 stage, and tumor size of 3 cm or less, with 0 to 3 positive lymph nodes after adequate axillary dissection or negative sentinel lymph node biopsy (N0-1), regardless of receptor status (ER, PR, HER2neu). Of the total 31 patients, 15 received APBI with multi-catheter interstitial brachytherapy (35 Gy in10 fractions over 5 days with a minimum interval of 6 hours between fractions) and 16 patients received WBI (27 Gy in 5 fractions over 5 days) with either 3DCRT or VMAT technique. Acute toxicity was assessed using the RTOG toxicity grading and breast cosmesis was assessed using the Harvard breast cosmesis score. Toxicity and cosmesis were assessed immediately after treatment, after one month, and after three months of treatment. Results were compared between groups using the Mann Whitney U test. All patients completed a 3-month follow-up after completion of treatment. There was no statistically significant difference between the 2 groups in terms of highest grade toxicity (p = 0.97) and acute toxicity immediately after RT (p = 1.0) and after 1 month of RT (p = 0.91). However, at 3 months, more patients in the WBI group had a residual skin reaction than in the APBI group (p = 0.03). There was no statistically significant difference in breast cosmesis scores at any time point. 53.3%, 6.6% had grade 1 and 2 skin toxicities respectively immediately after RT in the APBI group and 62.5% of patients had grade 1 skin toxicity in WBI group. After 1 month 26.6%, 26.6% & 13.3% patients had grade 2, grade 1 and grade 3 toxicities respectively. In the WBI group, at 1 month, 50%, 18.7% and 12.5% patients had grade 1, 3 and 2 skin toxicities respectively. At 3 months, 42.8% and 7.1% of patients in the APBI group had grade 1 and grade 2 toxicities, respectively. In the WBI group, 78.5% and 7.1% of patients had grade 1 and 2 skin toxicities respectively. In this study, no difference in acute toxicity or breast cosmesis was demonstrated between APBI-based interstitial brachytherapy and ultra-hypo-fractionated WBI. Since both regimens can be administered within 5 days, the decision between them is challenging for both physicians and patients. This study can be considered hypothesis-generating and used for further planning of equivalence or noninferiority studies.

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.

Friday, June 23, 20231:30 PM - 2:45 PMPL01 Presentation Time: 1:30 PM: Accelerated Partial Breast Irradiation Using Sole Interstitial Multicatheter Brachytherapy - GEC-ESTRO Phase 3 Non-Inferiority Trial: Sub-Analysis of 10-Year Results Reflecting Current Astro Recommendations for Patient Selection

Friday, June 23, 20231:30 PM - 2:45 PMPL01 Presentation Time: 1:30 PM: Accelerated Partial Breast Irradiation Using Sole Interstitial Multicatheter Brachytherapy - GEC-ESTRO Phase 3 Non-Inferiority Trial: Sub-Analysis of 10-Year Results Reflecting Current Astro Recommendations for Patient Selection

Development, implementation, and results of a simulation-based hands-on brachytherapy workshop for medical students

PurposeThe new Medical Licensing Regulations 2025 (Ärztliche Approbationsordnung, ÄApprO) require the development of competence-oriented teaching formats. In addition, there is a great need for high-quality teaching in the field of radiation oncology, which manifests itself already during medical school. For this reason, we developed a simulation-based, hands-on medical education format to teach competency in performing accelerated partial breast irradiation (APBI) with interstitial multicatheter brachytherapy for early breast cancer. In addition, we designed realistic breast models suitable for teaching both palpation of the female breast and implantation of brachytherapy catheters.MethodsFrom June 2021 to July 2022, 70 medical students took part in the hands-on brachytherapy workshop. After a propaedeutic introduction, the participants simulated the implantation of single-lead catheters under supervision using the silicone-based breast models. Correct catheter placement was subsequently assessed by CT scans. Participants rated their skills before and after the workshop on a six-point Likert scale in a standardized questionnaire.ResultsParticipants significantly improved their knowledge-based and practical skills on APBI in all items as assessed by a standardized questionnaire (mean sum score 42.4 before and 16.0 after the course, p < 0.001). The majority of respondents fully agreed that the workshop increased their interest in brachytherapy (mean 1.15, standard deviation [SD] 0.40 on the six-point Likert scale). The silicone-based breast model was found to be suitable for achieving the previously defined learning objectives (1.19, SD 0.47). The learning atmosphere and didactic quality were rated particularly well (mean 1.07, SD 0.26 and 1.13, SD 0.3 on the six-point Likert scale).ConclusionThe simulation-based medical education course for multicatheter brachytherapy can improve self-assessed technical competence. Residency programs should provide resources for this essential component of radiation oncology. This course is exemplary for the development of innovative practical and competence-based teaching formats to meet the current reforms in medical education.

Preliminary outcomes of accelerated partial breast irradiation by interstitial multicatheter brachytherapy with intraoperative free-hand catheter implantation in early breast cancer.

To evaluate the clinical feasibility of interstitial brachytherapy by intraoperative free-hand catheter implantation in the treatment of early breast cancer after breast-conserving surgery (BCS). Between January 2018 and December 2019, 44 patients with early breast cancer after BCS who met the inclusion criteria ≥45 years old, invasive carcinoma ≤3 cm or ductal carcinoma in situ <2.5 cm, estrogen receptor positive, lymph node negative, surgical margin negative, no distant metastasis, and an ECOG performance score ≤1 were enrolled in this phase II single-arm study. The postoperative irradiation field includes the tumor bed plus 2-cm margin in all directions, except in the anterior-posterior direction. The total prescribed tumor dose was 3400 cGy delivered in 10 fractions twice daily at 6-hour intervals. The primary endpoints were acute side effects, late treatment-related toxicity, and cosmetic outcome. The secondary endpoints were local recurrence-free survival (LRFS), regional recurrence-free survival (RRFS), distant metastasis-free survival (DMFS), and overall survival (OS). The median follow-up time was 33.5 months (mean, 32.9 months; range, 20-43 months). The cosmetic results were good to very good in 92.3% of the questionnaire respondents. The acute toxicities were mild, and no acute grade 3-4 toxicity was noted. Wound infection was noted in two patients (4.5%). There was only one event of regional lymph node recurrence in one patient. The 3-year LRFS, DMFS, and OS were 100%, and RRFS was 94.7%. For two patients who had a positive lymph node based on their final pathology reports, postoperative irradiation, including whole breast and regional lymph nodes, was added. Accelerated partial breast irradiation using interstitial brachytherapy with the intraoperative free-hand catheter implantation technique provides an alternative method of postoperative radiotherapy for selected patients with early breast cancer after BCS with acceptable toxicities.

HDR-brachytherapy for accelerated partial breast irradiation: Long-term experience from a Japanese institution.

We investigated the long-term oncological outcome of high-dose-rate (HDR) multicatheter interstitial brachytherapy (MIB) for adjuvant accelerated partial breast irradiation (APBI) after breast conserving surgery in Japanese patients. Between June 2002 and October 2011, 86 breast cancer patients were treated at National Hospital Organization Osaka National Hospital (trial number of the local institutional review board, 0329). Median age was 48 years (range, 26-73 years). Eighty patients had invasive and 6 patients non-invasive ductal carcinoma. Tumor stage distribution was pT0 in 2, pTis in 6, pT1 in 55, pT2 in 22, and pT3 in one patient, respectively. Twenty-seven patients had close/positive resection margins. Total physical HDR dose was 36-42 Gy in 6-7 fractions. At a median follow-up of 119 months (range, 13-189 months), the 10-year local control (LC) and overall survival rate was 93% and 88%, respectively. Concerning the 2009 Groupe Européen de Curiethérapie-European Society for Therapeutic Radiology and Oncology risk stratification scheme, the 10-year LC rate was 100%, 100%, and 91% for patients considered as low-risk, intermediate-risk, and high-risk, respectively. According to the 2018 American Brachytherapy Society risk stratification scheme, the 10-year LC rate was 100% and 90% for patients 'acceptable' and 'unacceptable' for APBI, respectively. Wound complications were observed in 7 patients (8%). Risk factors for wound complications were the omission of prophylactic antibiotics during MIB, open cavity implantation, and V100 ≥ 190 cc. No grade ≥ 3 late complications (CTCVE version 4.0) were observed. Adjuvant APBI using MIB is associated with favorable long-term oncological outcomes in Japanese patients for low-risk, intermediate-risk, and acceptable groups of patients.

Second Conservative Treatment for Ipsilateral Breast Cancer Recurrence: First 10-Year Oncological Outcome Report

<h3>Purpose/Objective(s)</h3> To analyze long-term oncological outcome after 2^nd conservative treatment (2^ndCT) for patients with ipsilateral 2^nd breast cancer event (2^ndBCE). <h3>Materials/Methods</h3> In this retrospective observational single institution study (Health-data-hub N°F20210402152843), patients with 2^ndBCE underwent 2^ndCT based on lumpectomy plus re-irradiation of the tumor bed with multicatheter interstitial brachytherapy (MIB). Oncological outcome was investigated based on 3^rd breast cancer event (3^rdBCE-FS) and metastatic disease (MD-FS) -free survivals as well as disease-free (DFS), cause-specific (CSS) and overall (OS) survival. Prognostic factors were analyzed. Late toxicity was reported. <h3>Results</h3> From 09/2000 to 05/2013, 113 pts presented a 2^ndBCE managed by 2^ndCT. Median relapse age was 64.8 years [31 - 85]. Median time interval between 1^st and 2^ndBCE was 162 months [24 - 420]. 2^ndIBE occurred in or close to the primary tumor bed in 47.8% and 31% respectively. Median 2^ndBCE size was 11.3 mm [1 - 40] while histological type was invasive ductal or lobular carcinoma in 77% and 13.3% respectively. Regarding APBI classification, patients were low, intermediate and high-risk in 37.2%, 44.4% and 18.6% respectively. Regarding molecular classification, patients were HR+/Her2-, Her2+ and triple negative in 88.8%, 5.1% and 6.1% respectively. New axillary lymph node dissection was performed in 5 pts (4.4%). Low and high-dose rate MIB were used for 27 (24%) and 86 pts (76%) respectively. Median HDR dose was 32 Gy [32 - 34]. Systemic treatments were hormonal (83.2%) and chemo- (13.3%) therapies. With a MFU of 121.5 months [48 – 129.6], 10-y 3^rdBCE-FS, MDFS, DFS, CSS and OS were 89% [83 - 96], 89% [83 - 96], 78% [70 - 87], 95% [91 - 100] and 94% [90 – 99] respectively. In univariate analysis, APBI classification was prognostic factor for 3^rdBCE (LR: 4.8%, IR: 12% and HR: 23.8%; p = 0.02) with a trend for DFS (LR: 19%, IR: 24% and HR: 42.9%; p = 0.055). Ninety-seven complications occurred in 73 pts (G1: 55.7%; G2: 38.1%; G3: 5.2%; G4: 1%) with cutaneous (36.1%) and sub-cutaneous (27.8%) fibrosis, telangiectasia (13.4%) and hyperpigmentation (4.1%). Cosmetic outcome was excellent, good, fair and poor in 70 pts (61.9%), 33 pts (29.2%), fair 9 pts (8%) and 1 pt (0.9%) respectively. <h3>Conclusion</h3> With long-term follow-up, 2^ndBCE managed with lumpectomy and tumor bed re-irradiation (MIB) allows the patient to avoid salvage mastectomy without compromise in oncological outcome. With about 5% of G≥3 late toxicity, final cosmetic outcome remains acceptable. Larger patient cohorts are needed to refine eligibility criteria for 2^ndCT while the place of systemic therapy remains under debate.

The comparison of transforming growth factor beta-1 serum levels in early-stage breast cancer patients treated with external beam whole breast irradiation plus boost versus interstitial brachytherapy accelerated partial breast irradiation

PURPOSETransforming growth factor beta-1 (TGF-β1) is a profibrotic cytokine used as an early biomarker to develop radiation-induced fibrosis (RIF). This study aimed to compare TGF-β1 serum levels in early-stage breast cancer patients treated with whole-breast radiation therapy (WBRT) plus boost versus accelerated partial breast irradiation (APBI) using multicatheter interstitial brachytherapy. METHODS AND MATERIALSThis clinical trial study was conducted on 20 women with early-stage breast cancer after breast-conserving surgery candidate for adjuvant radiotherapy in Golestan hospital, Ahvaz, in 2021. In one group APBI with high-dose-rate brachytherapy (n = 10), the other group WBRT with external beam radiation plus boost (n = 10) was performed. Serum level of TGF-β1 was evaluated before radiotherapy, immediately after the end of radiotherapy and three months after the end of radiotherapy by Enzyme-linked immunosorbent assay technique (ELISA). ResultsMedian serum TGF-β1 level before radiotherapy was not significantly different between the two groups (p = 0.971). In both APBI and WBRT groups, serum TGF-β1 levels significantly decreased immediately after radiotherapy compared to before treatment (p = 0.005 and p = 0.007, respectively); But three months after radiotherapy, serum TGF-β1 levels increased significantly in the WBRT group (40.50 to 77.41 pg/mL; p = 0.017), while no significant change was observed in the APBI group (24.75 to 30.50 pg/mL; p = 0.332). ConclusionSHigher TGF-β1 values in the WBRT group after radiotherapy can be used as an early and vital biomarker in this treatment, and this data may corroborate links between TGF-beta1 and fibrosis and fibrosis rates between APBI and WBRT; It also shows the preference for using the brachytherapy technique in this group of patients. However, due to the small number of samples, definitive conclusions require further prospective studies.

Comparison of Breast Cancer Radiotherapy Techniques Regarding Secondary Cancer Risk and Normal Tissue Complication Probability - Modelling and Measurements Using a 3D-Printed Phantom.

BackgroundRadiotherapy after breast-conserving therapy is a standard postoperative treatment of breast cancer, which can be carried out with a variety of irradiation techniques. The treatment planning must take into consideration detrimental effects on the neighbouring organs at risk—the lung, the heart, and the contralateral breast, which can include both short- and long-term effects represented by the normal tissue complication probability and secondary cancer risk.Patients and MethodsIn this planning study, we investigate intensity-modulated (IMRT) and three-dimensional conformal (3D-CRT) radiotherapy techniques including sequential or simultaneously integrated boosts as well as interstitial multicatheter brachytherapy boost techniques of 38 patients with breast-conserving surgery retrospectively. We furthermore develop a 3D-printed breast phantom add-on to allow for catheter placement and to measure the out-of-field dose using thermoluminescent dosimeters placed inside an anthropomorphic phantom. Finally, we estimate normal tissue complication probabilities using the Lyman–Kutcher–Burman model and secondary cancer risks using the linear non-threshold model (out-of-field) and the model by Schneider et al. (in-field).ResultsThe results depend on the combination of primary whole-breast irradiation and boost technique. The normal tissue complication probabilities for various endpoints are of the following order: 1%–2% (symptomatic pneumonitis, ipsilateral lung), 2%–3% (symptomatic pneumonitis, whole lung), and 1%–2% (radiation pneumonitis grade ≥ 2, whole lung). The additional relative risk of ischemic heart disease ranges from +25% to +35%. In-field secondary cancer risk of the ipsilateral lung in left-sided treatment is around 50 per 10,000 person-years for 20 years after exposure at age 55. Out-of-field estimation of secondary cancer risk results in approximately 5 per 10,000 person-years each for the contralateral lung and breast.ConclusionsIn general, 3D-CRT shows the best risk reduction in contrast to IMRT. Regarding the boost concepts, brachytherapy is the most effective method in order to minimise normal tissue complication probability and secondary cancer risk compared to teletherapy boost concepts. Hence, the 3D-CRT technique in combination with an interstitial multicatheter brachytherapy boost is most suitable in terms of risk avoidance for treating breast cancer with techniques including boost concepts.

Extreme hypofractionation in radiation therapy for patients with early breast cancer: what is the optimal technique?

Many radiation techniques have been employed in the trend of moving towards more hypofractionated regimens in the treatment of early breast cancer. This editorial articulates the advantages of using multi-catheter interstitial brachytherapy when delivering extreme hypofractionation for partial breast radiation.

A Japanese prospective multi-institutional feasibility study on accelerated partial breast irradiation using multicatheter interstitial brachytherapy: clinical results with a median follow-up of 60months.

We carried out the first multi-institutional prospective study on accelerated partial breast irradiation (APBI) via multicatheter interstitial brachytherapy in a shorter period for early breast cancer in Japan. Patient eligibility criteria included positive hormone receptors, tumors ≤ 3cm and TNM stage pN0M0. After breast-conserving surgery (Japanese cylindrical resection) and histological confirmation of negative surgical margins and the absence of lymph node metastasis, applicator implantation was performed either postoperatively or intraoperatively. High-dose-rate brachytherapy of 36Gy in 6 fractions was delivered. Forty-six patients from six institutions received this treatment regimen, and the median follow-up time was 60months (range 57-67months). The median resected breast tissue volume was 81 cm3 (range 28-260 cm3). No Grade 4 late sequela, local recurrence nor death due to breast cancer were observed. Grade 2-3 sequelae such as rib fracture (2%), soft tissue necrosis (9%), fibrosis (20%), and breast pain (9%) were observed. The resected breast tissue volumes of the patients who had Grade ≥ 2 fibrosis and Grade < 2 fibrosis were 105.9 ± 32.3 cm3 and 76.3 ± 45.6 cm3, respectively, p = 0.02. The overall cosmetic outcome score of Excellent/Good was 74% at 60months after APBI. Grade ≥ 1 fibrosis was observed in 44% and 92% of patients who scored Excellent/Good and Fair/Poor, respectively, p = 0.004. This study showed excellent local control and survival results with minimal late sequelae.

CyberKnife versus multicatheter interstitial brachytherapy for accelerated partial breast irradiation: a dosimetrical assessment with focus on organs at risk.

BackgroundThe purpose of the study was to dosimetrically compare multicatheter interstitial brachytherapy (MIBT) and stereotactic radiotherapy with CyberKnife (CK) for accelerated partial breast irradiation with special focus on dose to organs at risk (OARs).Materials and methodsTreatment plans of thirty-one patients treated with MIBT were selected and additional CK plans were created on the same CT images. The OARs included ipsilateral non-target and contralateral breast, ipsilateral and contralateral lung, skin, ribs, and heart for left sided cases. The fractionation was identical (4 × 6.25 Gy). Dose-volume parameters were calculated for both techniques and compared.ResultsThe D90 of the PTV for MIBT and CK were similar (102.4% vs. 103.6%, p = 0.0654), but in COIN the MIBT achieved lower value (0.75 vs. 0.91, p < 0.001). Regarding the V100 parameter of non-target breast CK performed slightly better than MIBT (V100: 1.1% vs. 1.6%), but for V90, V50 and V25 MIBT resulted in less dose. Every examined parameter of ipsilateral lung, skin, ribs and contralateral lung was significantly smaller for MIBT than for CK. Protection of the heart was slightly better with MIBT, but only the difference of D2cm3 was statistically significant (17.3% vs. 20.4%, p = 0.0311). There were no significant differences among the dose-volume parameters of the contralateral breast.ConclusionThe target volume can be properly irradiated by both techniques with high conformity and similar dose to the OARs. MIBT provides more advantageous plans than CK, except for dose conformity and the dosimetry of the heart and contralateral breast. More studies are needed to analyze whether these dosimetrical findings have clinical significance.

3D-Image-Guided Multi-Catheter Interstitial Brachytherapy for Bulky and High-Risk Stage IIB-IVB Cervical Cancer.

Simple SummaryThe prognosis of locally advanced cervical cancer still remains poor. Recently, image-guided brachytherapy ameliorated local control and pelvic control in these patients. Additionally, concurrent chemoradiotherapy with interstitial brachytherapy (ISBT) demonstrated more favorable outcomes than that with intracavity brachytherapy. The purpose of our study was to evaluate the efficacy and safety of CT-MRI-guided multi-catheter ISBT for bulky (≥4 cm) and high-risk stage IIB-IVB cervical cancer. Total of 18 patients with squamous cell carcinoma received concurrent chemoradiotherapy with ISBT were assessed. Four (22.2%), seven (38.9%), and seven (38.9%) patients were diagnosed with stage II, III, and IV cervical cancer, respectively. The four-year local control, pelvic control, disease-free survival, and overall survival rates were 100%, 100%, 81.6%, and 87.8%, respectively. Although three (16.7%) patients experienced grade 3 late adverse events, no one had procedure-related complications. CT-MRI-guided multi-catheter ISBT could be a promising treatment strategy for locally advanced cervical cancer. This study aimed to evaluate the efficacy and safety of computed tomography-magnetic resonance imaging (CT-MRI)-guided multi-catheter interstitial brachytherapy for patients with bulky (≥4 cm) and high-risk, stage IIB–IVB advanced cervical cancer. Eighteen patients who underwent concurrent chemoradiotherapy with multi-catheter interstitial brachytherapy between September 2014 and August 2020 were enrolled. The prescribed dose of external beam radiotherapy was 45–50.4 Gy, and the brachytherapy high-dose-rate aim was 25–30 Gy per 5 fractions. The endpoints were four-year local and pelvic control rates, four-year disease-free and overall survival rates, and the adverse events rate. The median follow-up period was 48.4 months (9.1–87.5 months). Fifteen patients received concurrent cisplatin therapy (40 mg/m2, q1week). Four (22.2%), seven (38.9%), and seven (38.9%) patients had stage II, III, and IV cervical cancer, respectively. Pelvic and para-aortic lymph node metastases were observed in 11 (61.1%) and 2 (11.1%) patients, respectively. The median pre-treatment volume was 87.5 cm3. The four-year local control, pelvic control, disease-free survival, and overall survival rates were 100%, 100%, 81.6%, and 87.8%, respectively. Three (16.7%) patients experienced grade 3 adverse events, and none experienced grade 4–5 adverse events. CT-MRI-guided multi-catheter interstitial brachytherapy could be a promising treatment strategy for locally advanced cervical cancer.