Supraclavicular Field Research Articles

Radiation-induced Esophagitis in Breast Cancer Patients Treated With Supraclavicular Field Irradiation.

The objective of this research was to assess the frequency and intensity of radiation-induced esophagitis in breast cancer patients treated with supraclavicular radiotherapy field irradiation. This study involved 100 patients with positive lymph nodes receiving radiotherapy to the breast or chest wall along with supraclavicular field irradiation, with toxicity levels assessed weekly. Treatment utilized the 3D conformal technique, and variables, such as mean and maximum dose to the cervical esophagus, mean dose to the entire esophagus, and length of the esophagus within the treated area were recorded. The occurrence of grade 2 or higher esophagitis was 48%, with patients facing the risk of developing such esophagitis at an average dose of 13 Gy. The probability of grade 2 esophagitis occurring at doses exceeding 13 Gy was statistically significantly higher (p<0.001) with an odds ratio of 24.4. Limiting the mean cervical esophagus dose to <13 Gy could help reduce the frequency and severity of grade 2 or higher toxicity.

Correlation of new two-dimensional geometrical parameters to lung and heart dose-volume parameters in breast cancer radiation therapy.

To develop new two-dimensional geometric parameters for pulmonary and cardiac dose estimation in left-sided breast cancer radiation therapy without dose-volume histogram (DVH). On the CT image of 90 patients with left breast cancer, treatment planning was performed using two opposed tangent fields with/without supraclavicular. The field-in-field technique and 6MV photons were used. From DVH dosimetric parameters of mean dose, Vx (x (Gy) =5, 10, 15, 20, 30, 40, 50) were calculated, and from heart and lung outlines on the beam's eye view, new geometric parameters of percent of lung area in tangent and supraclavicular fields (%area of the lung in the tangent (ALT), %ALS) and percent of heart in tangent field (%area of the heart in the tangent (AHT)) were measured. Correlation, regression, and diagnostic performance by receiver operating characteristic curve (ROC) were investigated for statistical analysis. The Pearson coefficient between %ALT and Vx (x = 10, 15, 20, 30, 40) show strong correlation in patient treatment with only opposed tangents (>0.85) and weaker in treatment by opposed tangents with supraclavicular (0.56-0.88), the %ALS indicate weak correlation (<0.5) and %AHT show strong correlation (0.93-0.98). The regression analysis shows a positive relation between %ALT and mean dose (R2 = 0.8), V20Gy (R2 = 0.9) in the lung (tangent treatment), and between %AHT and mean dose (R2 = 0.9), V20Gy (R2 = 1.0) in the heart. The ROC analysis shows by %ALT <20.3 for treatment by just opposed fields, %ALT <22.1% for treatment tangents with supra, and %AHT <11.6%, practical lung and heart dose constraints are addressed. The proposed geometric parameters could replace previous one-dimensional maximum and central distances for predicting doses to lung and heart. This study presents simple geometric parameters that could estimate pulmonary and cardiac dose in left breast cancer treatment from a 2D radiograph.

1141: Review of supraclavicular radiotherapy field and surgical clip position post axillary node clearance

1141: Review of supraclavicular radiotherapy field and surgical clip position post axillary node clearance

Preliminary results of hypofractionated radiotherapy in breast cancer in Chandigarh, India: single-centre, non-inferiority, open-label, randomised, phase 3 trial

Globally, most of the randomised trials with hypofractionation in patients with breast cancer have used 3-dimensional conformal radiotherapy technique (3D-CRT). As facilities for 3D-CRT technique may not be available in low-resource settings, there is a need to see if hypofractionation is feasible and safe with 2-dimensional (2-D) technique. In this study, we compared a 3-week radiation schedule with a 2-week schedule of hypofractionated radiotherapy in patients with breast cancer with 2-D technique. The current study was an open-label, randomised, phase 3 trial. Patients with breast cancer, stage I-III, post mastectomy or after breast conservative surgery who needed adjuvant locoregional radiotherapy were randomised in the Department of Radiotherapy & Oncology, Post Graduate Institute of Medical Education & Research (PGIMER), Chandigarh, India; to 34Gy in 10 fractions over 2 weeks (2-week arm) or 35Gy in 15 fractions over 3 weeks to the chest wall and 40Gy/15#/3wks to breast and supraclavicular fossa (3-week arm). Boost dose when indicated was 8-10Gy/2-4#/2-4 days in both the arms. Patients were planned on a 2-dimensional (2D) simulator with 2 tangential fields to breast/chest wall and incident supraclavicular fossa field. Acute toxicity was assessed using the Radiation Therapy Oncology Group (RTOG) grading scale. Assessments were carried out weekly during radiotherapy and at 4 weeks after treatment by the physician. Cosmetic outcome was assessed using the Harvard/National Surgical Adjuvant Breast and Bowel Project (NSABP)/RTOG scale. The toxicity rates between the two arms were compared using Fisher's exact tests. The trial was approved by institutional ethics committee and registered with ClinicalTrials.gov, number NCT04075058. This study included 1121 eligible patients from June 2015 to December 2020. Median follow-up was 35 months (6-84 months). Mean age was 48 years (24-75 years). The patient characteristics were comparable between the two arms except for more mastectomies in the 3-week arm and more node-positive patients in the 2-week arm. There were more oestrogen receptor-positive tumors in the 3-week arm. Acute skin toxicities were comparable between the two arms. Grade 2 and 3 skin toxicity was 100 (18%) and 82 (15%); and 16 (3%) and 12 (2%) in the 3-week and 2-week arm (p=0.21), respectively. Cosmetic outcome was assessed as Excellent or Good for 89% of patients in the 3-week arm as compared to 94% in the 2-week arm (p=0.004). The two radiation schedules were comparable in terms of acute skin toxicity. The cosmetic outcome was better with the 2-week schedule. The preliminary findings indicate 2-week radiotherapy schedule with 2-D technique was better than the 3-week schedule in patients with breast cancer. However, disease outcomes and late-term toxicities need to be further checked. This study was funded by Science and Engineering Research Board (SERB), India.

Investigation of the dose profiles in the junction region between the supraclavicular and tangential fields

Investigation of the dose profiles in the junction region between the supraclavicular and tangential fields

Supraclavicular Irradiation Induces Lymphedema in Breast Cancer Patients Treated with Axillary Lymph Node Dissection and Taxane‐Containing Chemotherapy

Purpose. Breast cancer‐related lymphedema (LE) significantly impairs the patients’ quality of life. Axillary lymph node dissection (ALND) is a strong risk factor for LE in breast cancer surgery. In addition, postoperative administration of docetaxel (DTX) has been reported to be a risk factor for LE in patients who undergo ALND. Herein, we performed the risk of objective LE after ALND. Methods. Patients who visited the medical follow‐up clinic between 12 November 2018 and 11 January 2019 and at least one year postoperatively were eligible for this study. The risk factors for objective LE according to taxane‐containing regimen, radiation therapy, and body mass index and the effects of a taxane‐containing regimen followed by supraclavicular irradiation on LE were examined. Results. A total of 214 patients were included in this analysis, and objective LE was observed in 52 patients (24%). Univariate and multivariate analyses showed that only supraclavicular field irradiation was a statistically significant risk factor for objective LE. In addition, the sequential use of taxane‐containing regimens and supraclavicular RT was shown to be a more likely risk factor for LE than ALND alone. We also compared each taxane regimen with supraclavicular RT and found that DTX was more likely to be a risk factor for LE in cases of sequential use of supraclavicular RT than with ALND alone. However, when comparing DTX with supraclavicular RT and PTX with supraclavicular RT directly, there was no statistically significant difference in the risk of objective LE between the two groups. Conclusion. The risk for LE was more likely to be higher with the sequential use of taxane‐containing chemotherapy and supraclavicular field irradiation. Therefore, management of LE is important in these cases.

AI segmentation as a quality improvement tool in radiotherapy planning for breast cancer

AI segmentation has been recently introduced in the local department for delineation of targets and organs-at-risk (OAR) for a wide range of tumour sites. For breast radiotherapy, AI segmentation can provide target delineation (breast and lymph nodes) and required OAR, and this has enabled a stepwise series of improvements to the local planning technique.Clinician feedback deemed 67 - 89 % of nodal target volumes required no edits or only minor edits, so AI breast and lymph nodes volumes were first used to guide tangent and supraclavicular field placement, instead of a bony-anatomy based technique.Next, evolution from anatomical field-placement to true inverse optimised planning was introduced using AI to create the required target volumes. For internal mammary node (IMN) treatments, the previous 3-field technique prohibited Deep Inspiration breath-hold (DIBH), due to the couch rotation used to match field edges. The roll-out of VMAT (volumetric-modulated arc therapy) with DIBH enabled by AI therefore resulted in a dose reduction to ipsi-lateral lung, and in mean heart dose compared to the old 3-field technique. Median time from CT scan to VMAT IMN plan approval reduced from 12 days (with manual contouring) to 7 days using reviewed and edited AI-generated volumes.Consistent, high-quality contours for 9 OAR and breast PTVs for all patients facilitates comparison with NHS-E scorecards as a benchmark for plan quality. Workflows have been simplified, with significant time-savings. DIBH radiotherapy is now available to more patients, further improving dose sparing for heart and lung.

Is it the Type of Axillary Surgery or the Number of Removed Lymph Nodes That Increases the Risk of Breast Cancer Related Lymphedema (BCRL)? Results from a Prospective Screening Trial

Axillary surgery has been identified as the main risk factor for BCRL regardless the delivery of regional nodal radiation (RLNR). Yet it remains unknown if it is the type of axillary surgery or the number of removed lymph nodes (LN) that increases BCRL risks. Between 2008 and 2021, 3,350 patients (pts) who received surgery for breast cancer were enrolled in a lymphedema screening trial. Patients with bilateral breast cancer or without axillary surgery were excluded. Perometry was used to assess limb volume preoperatively in all patients. BCRL was defined as a ≥10% relative arm-volume increase arising >3 months postoperatively. The cohort was divided by axillary surgery type: axillary lymph node dissection (ALND) and sentinel lymph node biopsy (SLNB). Radiation was delivered using 3D conformal technique and RLNR was defined as the usage of anterior supraclavicular field. No hypofractionation was used and doses ranged between 50 and 50.4 Gy in 25-28 fractions. Multivariable Cox proportional hazard models compared the cumulative incidence of BCRL and local failure between different patient groups. After applying inclusion criteria, 2,623 pts were available with overall median follow-up s of 6.1 years. Of the entire cohort, 709 (27%) had ALND with a median of 16 LN removed, while 1,914 (73%) received SLNB only with a median of 2 LN removed. The median number of malignant LN and patients receiving RLNR was higher in ALND group compared to SLNB only group. Frequency distribution analysis showed that the main overlap between ALND and SLNB only groups happen in the range of 3-11 LN removed. Therefore, the primary analysis focused only on pts with 3-11 LN across both groups (n = 690: ALND n = 140, SLNB n = 550). The multivariable model adjusted for BMI, RLNR, age and breast surgery showed that in this group with 3-11 LN removed in both cohorts, ALND remained significantly associated with BCRL (HR: 4.2, p<0.0001). Separate analyses for the entire SLNB only group and ALND groups were conducted to evaluate if the BCRL risk increases per each removed LN within the same axillary surgery group. The multivariable analysis for SLNB only pts(N = 1,914) showed that for each LN removed the risk of BCRL did not increase significantly (HR:1.06, p = 0.3), similarly for ALND group (N = 709) for each LN removed (HR:1.02, p = 0.08). For pts with pathologic N2-N3 disease and clinical node negative without neoadjuvant chemotherapy receiving ALND, the number of LN removed did not significantly improve neither Local control (HR:1.02, p = 0.8) nor distant disease survival (HR:1.01, p = 0.6). ALND procedure per se is the main risk factor for BCRL not the number of LNs removed. For high-risk pts with >N2 disease, aggressive ALND did not improve tumor outcome. De-escalation with targeted axillary sampling followed by RLNR should be evaluated. Future lymphedema research should account for type of axillary surgery instead of number of LNs removed as a factor. (NCT01521741).

Cell-Free DNA Fragmentomics for Early Detection of Malignant Transformation in NF1 Patients Harboring Plexiform Neurofibromas

Malignant peripheral nerve sheath tumors (MPNST) are aggressive soft tissue sarcomas that are resistant to radiotherapy and chemotherapy, and are associated with poor survival. MPNST typically arise from benign or atypical plexiform neurofibromas (PN) in the setting of neurofibromatosis type 1 (NF1). Unfortunately, early detection by imaging and clinical examination remains very challenging. We hypothesize that cell-free DNA fragmentomic analysis can be used to precisely detect the risk for developing MPNST in NF1 patients, which could significantly improve clinical outcomes in the future through early cancer detection. We performed low-pass whole genome sequencing of plasma cell-free DNA samples from healthy controls (n = 21), patients with PN (n = 113), AN (n = 39) and MPNST (n = 71). Cell-free DNA was analyzed at a per-fragment level by tracking 4-nucleotide end motifs, and using a bin-wise fragmentomic machine learning approach called DELFI, which integrates across ratios of short (100-150 bp) versus long (151-220 bp) fragments in 5 megabase bins across the genome. End motif frequencies were compared between MPNST and PN patients, and receiver operating characteristic (ROC) analysis was used to classify disease states using DELFI fragmentomic scores. Using DELFI for genome-wide fragmentomics, followed by ROC analysis, we obtained the following accuracies: MPNST vs. AN (acc 0.62), MPNST vs. PN (acc 0.83), MPNST vs. healthy (acc 0.86), AN vs. PN (acc 0.87), AN vs. healthy (acc 0.72) and PN vs. healthy (acc 0.88). DELFI-based cell-free DNA fragmentomics was superior to the ichor CNA-based copy number alteration classifier that we published previously (Szymanski et al. PLOS Medicine, 2021) for all the aforementioned group comparisons (p < 0.001 by McNemar's test). Strikingly, the two AN cases with DELFI scores most closely resembling MPNST were separately identified by independent clinical care teams to have very high-risk features and recent history warranting short-interval follow up. Specifically, one patient had a paraspinal AN exhibiting new onset pain and rapid growth on imaging, while the other had increased FDG uptake of multiple AN lesions in a supraclavicular field treated years earlier with radiotherapy. We also measured fragment end motifs across different patient groups, and found that the CTCA end motif was more commonly present in cell-free DNA from MPNST and PN patients compared to healthy donors (Bonferroni-corrected p-value < 0.001). This study suggests that fragmentomic analysis of cell-free DNA can accurately risk-stratify NF1 patients with plexiform neurofibromas. Cell-free DNA fragmentomics outperformed our previously published copy number alteration method for distinguishing closely related patient subgroups with different malignancy risks. Atypical neurofibroma patients with cell-free DNA fragmentomic scores suggestive of MPNST were deemed clinically very high-risk for malignant transformation.

A Prospective Study of Radiation Therapy After Immediate Lymphatic Reconstruction: Analysis of the Dosimetric Implications

Axillary lymph node dissection (ALND) and regional nodal irradiation (RNI) are the primary causes of breast cancer-related lymphedema (BCRL). Immediate lymphatic reconstruction (ILR) is a novel surgical procedure that reduces the incidence of BCRL after ALND. The ILR anastomosis is placed in a location thought to be outside the standard radiation therapy fields to prevent radiation-induced fibrosis of the reconstructed vessels; however, there is excess risk of BCRL from RNI even after ILR. The purpose of this study was to understand the radiation dose distribution in relation to the ILR anastomosis. This prospective study included 13 patients treated with ALND/ILR from October 2020 to June 2022. A twirl clip deployed during surgery was used to identify the ILR anastomosis site during radiation treatment planning. All cases were planned using a 3D-conformal technique with opposed tangents and an obliqued supraclavicular (SCV) field. RNI deliberately targeted axillary Levels 1 to 3 and the SCV nodal region in 4 patients and was limited to Level 3 and SCV nodes in 9 patients. The ILR clip was located in Level 1 in 12 patients and Level 2 in 1 patient. In patients with radiation directed at only Level 3 and SCV, the ILR clip was still within the radiation field in 5 of these patients and received a median dose of 3939 cGy (range, 2025-4961 cGy). The median dose to the ILR clip was 3939 cGy (range, 139-4961 cGy) for the entire cohort. The median dose was 4275 cGy (range, 2025-4961 cGy) when the ILR clip was within any radiation field and 233 cGy (range, 139-280 cGy) when the clip was outside all fields. The ILR anastomosis was often directly irradiated with 3D-conformal techniques and received substantial radiation dose, even when the site was not deliberately targeted. Long-term analysis will help determine whether minimizing radiation dose to the anastomosis will decrease BCRL rates.

Abstract P6-03-05: Clinico-pathological co-variates define a predictive model of breast cancer related lymphoedema (BCRL) in patients undergoing axillary surgery for breast cancer

Abstract Clinico-pathological co-variates define a predictive model of breast cancer related lymphoedema (BCRL) in patients undergoing axillary surgery for breast cancer CC Tang1*, J Timbres2*, KWD Ramsey1, A Mera2, S Irshad2, E Sawyer2, AA Khan1 1 Department of Plastic Surgery, The Royal Marsden Hospital, London, UK 2 School of Cancer and Pharmaceutical Sciences, Faculty of Life Sciences and Medicine, Guy’s Cancer Centre, King’s College London, London, UK. *These authors contributed equally Introduction Breast cancer-related lymphoedema (BCRL) negatively impacts body image, limb function and quality-of-life during cancer survivorship and affects 20% of women undergoing axillary clearance (ALND).1 Stratifying women undergoing axillary intervention into high- and low-risk groups for BCRL is important to identify those most likely to benefit from surgical interventions for lymphoedema prevention (eg LYMPHA) and mitigate BCRL risk in this subset of patients. In this study, we aimed to identify prognostic factors for lymphoedema incidence to develop a more accurate model of BCRL risk. Methods We performed a retrospective cohort study of breast cancer patients undergoing axillary surgery with (Ly+) and without (Ly-) subsequent lymphoedema. Controls were identified from the Breast Cancer Clinical Database, Guy’s and St Thomas’ Hospital NHS Foundation Trust (GSTT)) and diagnosed between 2000-2016, while cases were identified from the Lymphoedema Clinic at GSTT, diagnosed between 2000-2020. A multivariate logistic regression model was derived from univariate analyses using a stepwise, iterative process, confirmed with lasso regression, and evaluated within training and validation datasets to define a predictive risk score using methods described by Pavlou et al.2 Results 2040 patients (Ly+=541, Ly-=1499) who underwent axillary surgery (ALND = 1171, SLNB = 755) (were included in our analysis with a median follow up of 7.2 years (Ly+) and 9.8 years (Ly-). The final predictive model of BCRL risk contained variables for: mastectomy, grade, T-stage, N-stage, ER status, chemotherapy and radiotherapy. Here, specifically radiotherapy including a supraclavicular fossa field was associated with developing lymphoedema. The Hosmer–Lemeshow goodness-of-fit test showed the model to be well calibrated, and evaluation of the risk score using ROC curves showed good discrimination (AUC: 0.795). Lymphoedema was not found to negatively affect overall (unadjusted HR: 1.19 (95% CI: 0.92-1.53); p=0.178 and adjusted HR: 0.53 (95% CI: 0.38-0.73); p&amp;lt; 0.001) or disease free (unadjusted HR: 2.03 (95% CI: 1.59-2.61); p&amp;lt; 0.001 and adjusted HR: 0.92 (95% CI: 0.68-1.23); p=0.57) survival. Conclusion Our study identified clinico-pathological factors such as mastectomy, grade, T-stage, N-stage, ER status, chemo- and radiotherapy (specifically radiotherapy including a supraclavicular fossa field) to be predictive of developing BCRL following axillary surgery. Our model requires further validation but may have utility in stratifying patients for whom surgical strategies for lymphoedema prevention could be deployed to mitigate BCRL risk.

Radiation-Induced Localized Bullous Pemphigoid.

Radiation-Induced Localized Bullous Pemphigoid.

Abstract GS5-12: Hypofractionated Radiotherapy in patients with Breast Cancer (HRBC): Acute toxicity data of a phase III randomized study

Abstract Background HRBC is a phase III randomized open label study of adjuvant radiotherapy in patients with breast cancer. In this study we compared a 3 weeks radiation schedule with 2 weeks. Materials and methods Patients with breast cancer, stage I-III, post mastectomy or after breast conservative surgery who needed adjuvant locoregional radiotherapy were randomized to 34Gy in 10 fractions over 2 weeks (study arm) or 35Gy in 15 fractions over 3 weeks to the chest wall and 40Gy/15#/3wks to breast and supraclavicular fossa (control arm). Boost dose when indicated was 8Gy/2# in both the arms. Patients were planned on simulator with 2 tangential fields to breast/chest wall and incident supraclavicular fossa field. Acute toxicity was assessed using a RTOG grading system. Assessment was carried out weekly during radiotherapy and at 4 weeks after treatment by the physician. Cosmetic outcome was assessed using Harvard/NSABP/RTOG scale. The toxicity between the two arms was compared using Fisher’s exact test. The trial was approved by institutional ethics committee. This trial is registered with ClinicalTrials.gov, number NCT04075058. Results This study included 1121 patients. Median follow up was 35 months (range 6-84 months). Mean age was 48 year (range 24-80 years). The patient characteristics were comparable between the two arms except for more mastectomies in the 3 week arm and more node positive patients in the 2 week arm. There were more oestrogen receptor positive tumors in the 3 week arm. Acute skin toxicities were comparable between the two arms. Grade 2 and 3 skin toxicity was 98(17%) and 82(15%); and 16(3%) and 10(2%) in the 3 week and 2 week arm (p=0.15), respectively. Cosmetic outcome was significantly better in 2 week arm 94% as compared to 90% in the 3 week arm (p=0.016). Conclusion The two radiation schedules were comparable in terms of acute skin toxicity. Cosmetic outcome was better in the 2 week schedule. Citation Format: Budhi Singh Yadav, Divya Dahiya, Manish Gupta. Hypofractionated Radiotherapy in patients with Breast Cancer (HRBC): Acute toxicity data of a phase III randomized study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr GS5-12.

Stability and reproducibility comparisons between deep inspiration breath-hold techniques for left-sided breast cancer patients: A prospective study.

Deep inspiration breath-hold (DIBH) is crucial in reducing the lung and cardiac dose for treatment of left-sided breast cancer. We compared the stability and reproducibility of two DIBH techniques: Active Breathing Coordinator (ABC) and VisionRT (VRT). We examined intra- and inter-fraction positional variation of the left lung. Eight left-sided breast cancer patients were monitored with electronic portal imaging during breath-hold (BH) at every fraction. For each patient, half of the fractions were treated using ABC and the other half with VRT, with an equal amount starting with either ABC or VRT. The lung in each portal image was delineated, and the variation of its area was evaluated. Intrafraction stability was evaluated as the mean coefficient of variation (CV) of the lung area for the supraclavicular (SCV) and left lateral (LLat) field over the course of treatment. Reproducibility was the CV for the first image of each fraction. Daily session time and total imaging monitor units (MU) used in patient positioning were recorded. The mean intrafraction stability across all patients for the LLat field was 1.3±0.7% and 1.5±0.9% for VRT and ABC, respectively. Similarly, this was 1.5±0.7% and 1.6±0.8% for VRT and ABC, respectively, for the SCV field. The mean interfraction reproducibility for the LLat field was 11.0±3.4% and 14.9±6.0% for VRT and ABC, respectively. Similarly, this was 13.0±2.5% and 14.8±9% for VRT and ABC, respectively, for the SCV. No difference was observed in the number of verification images required for either technique. The stability and reproducibility were found to be comparable between ABC and VRT. ABC can have larger interfractional variation with less feedback to the treating therapist compared to VRT as shown in the increase in geometric misses at the matchline.

Thyroid volume changes following adjuvant radiation therapy for breast cancer

Background and purposeIncidental thyroid gland irradiation frequently occurs in breast cancer patients who receive regional nodal irradiation (RNI) to the supraclavicular (SCV) region. Recent studies suggest hypothyroidism (HT) is a complication of radiation therapy (RT) that includes SCV fields. We retrospectively analyzed patients who received RNI to evaluate thyroid gland evolution following RT as well as its association with the development of HT. Materials and methods61 breast cancer patients received SCV-directed RT between 2007 and 2019 and met inclusion criteria. Thyroid glands were retrospectively contoured on CT simulation and follow-up images. Individual dose-volume histograms were analyzed to determine thyroid volume within and outside specific isodose lines. Relative thyroid volume changes based on different radiation doses were estimated by fusing post-RT scans with CT simulation. Logistic regression was performed to assess thyroid volume changes as a factor in the development of HT. ResultsMedian pre-treatment thyroid volume was 11.8 cc (range: 6.3–74.1 cc) with a median of 42.2 % within the 20 Gy and 23.2 % within the 40 Gy isodose lines. A significant decrease in thyroid volume was noted by 1-year post-treatment (p < 0.0001) and thereafter. By 4 years post-treatment, average thyroid volume was decreased by 29.7 % (range: 2.3–64.4 %). Thyroid volume receiving 40 Gy or higher demonstrated a greater decrease compared to those receiving lower irradiation dosage. HT occurred in 17 patients (27.9 %). Patients who developed HT displayed a larger decrease in the thyroid volume receiving between 20 and 40 Gy at 12 months (p = 0.033). ConclusionOur study demonstrates for the first time that a reduction in thyroid volume may be seen as early as 6 months after SCV-directed RT for breast cancer, which correlates with development of clinical and subclinical HT. Furthermore, a dose-dependent correlation exists between thyroid subvolume reduction and SCV-directed RT in breast cancer patients. As feasible, efforts should be made to reduce the dose to the thyroid in patients who undergo RNI for breast cancer.

Clinical implementation of the first Cherenkov imaging system in a community-based hospital.

PurposeTo document experiences with one year of clinical implementation of the first Cherenkov imaging system and share the methods that we developed to utilize Cherenkov imaging to improve treatment delivery accuracy in real-time.MethodsA Cherenkov imaging system was installed commissioned and calibrated for clinical use. The optimal room lighting conditions and imaging setup protocols were developed to optimize both image quality and patient experience. The Cherenkov images were analyzed for treatment setup and beam delivery verification.ResultsWe have successfully implemented a clinical Cherenkov imaging system in a community-based hospital. Several radiation therapy patient setup anomalies were found in 1) exit dose to the contralateral breast, 2) dose to the chin due to head rotation for a supraclavicular field, 3) intrafractional patient motion during beam delivery, and 4) large variability (0.5 cm to 5 cm) in arm position between fractions. The system was used to deliver deep inspiration breath hold (DIBH) treatment delivery of an electron treatment beam. Clinical process and procedures were improved to mitigate the identified issues to ensure treatment delivery safety and to improve treatment accuracy.ConclusionThe Cherenkov imaging system has proven to be a valuable clinical tool for the improvement of treatment delivery safety and accuracy at our hospital. With only minimal training the therapists were able to adjust or correct treatment positions during treatment delivery as needed. With future Cherenkov software developments Cherenkov imaging systems could provide daily surface guided radiotherapy (SGRT) and real time treatment delivery quality control for all 3D and clinical setup patients without adding additional radiation image dose as in standard kV, MV and CBCT image verifications. Cherenkov imaging can greatly improve clinical efficiency and accuracy, making real time dose delivery consistency verification and SGRT a reality.

Regional Lymph Node Radiotherapy in Breast Cancer: Single Anterior Supraclavicular Field vs. Two Anterior and Posterior Opposed Supraclavicular Fields

Objective: To compare different alternatives for the two regional Auxiliary lymph node (AXLN) and Supraclavicular lympnode (SCLNs) treatment programs by providing a perfect balance of homogeneity and by arranging target volume coverage.Study Design: Cross sectional.Place and Duration of Study: The study was conducted from 11th March 2020 to 11th September 2020 at the oncology ward of the Tertiary Care Hospital, Multan.Materials and Methods: Forty breast cancer patients were included in the study. A three-dimensional (3D) planning system and a 6MV Compact machine technique were planned for the patients with breast cancer treated with post-surgery radiation that included the SC field.Results: The minimum weight of these patients was 40kg, maximum 110kg. The minimum height was 148cm, the highest 175cm. Measurements averaged 63.5kg and 163.5cm respectively. The depth of the SC was 3-7 cm whereas the diameter of the chest wall was 12-21 cm. Body mass index has a relation with the mean of both the diameter of the chest wall and SC depth.Conclusion: Two anterior and posterior opposed supraclavicular field is a better choice for the treatment as compared to single anterior supraclavicular fields. Several hot spots were produced at the two anterior and posterior opposed supraclavicular fields due to the use of single-photon.&#x0D; How to cite this: Anwer A, Ijaz A, Arshad M. Regional Lymph Node Radiotherapy in Breast Cancer: Single Anterior Supraclavicular Field vs. Two Anterior and Posterior Opposed Supraclavicular Fields. Life and Science. 2022; 3(2): 70-74. doi: http://doi.org/10.37185/LnS.1.1.202&#x0D; This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

A Dosimetric Analysis of Incidental Radiation to the Internal Mammary Nodes with a Three-field Chest Wall Technique

Objectives: The authors’ aim was to conduct a dosimetric analysis of the incidental radiation dose to the internal mammary node (IMN) region using a three-field chest wall technique (TFCWT). Methods: This retrospective study utilized 3D-conformal radiotherapy plans of 50 post-mastectomy patients (25 left-sided and 25 right-sided). All plans used the TFCWT, composed of narrowed tangents matched medially to an AP electron field, and prescribed a total dose of 50 Gy in 28 fractions. The IMNs were not intentionally treated in all included plans. Results: The mean dose to the IMN-planning target volume (IMN-PTV) was 45.1 Gy (26.4 - 55.6, SD 6.5). Minimum doses received by 95% and 90% of the IMN-PTV were 29.3 Gy (8 - 49, SD 10.0) and 34.0 Gy (10.0 - 52.0, SD 8.6), respectively. The percent volume of IMN-PTV receiving 100%, 95%, 90%, and 80% were 47.4% (3 - 94, SD 21.6), 55.6% (6 - 97, SD 22.4), 61.92% (7 - 98, SD 22.2), and 72.61% (18-100, SD 20.2), respectively. The average ipsilateral lung V20 Gy (with supraclavicular fields) was 25.0% (16 - 29, SD 3.4), and the average heart mean dose was 2.5 Gy (0.5 - 7.9, SD 1.58). Conclusion: Although the results suggest increased IMN radiation doses with the TFCWT when compared historically to standard tangents, the incidental doses are comparatively less than that traditionally prescribed to the IMNs in high-risk patients. It is unknown whether this incidental IMN dose confers any clinical benefit.

Tangential VMAT vs. 3D-Conformal Radiotherapy for Left-Sided Whole Breast and Regional Lymph Node Irradiation

<h3>Purpose/Objective(s)</h3> Whole breast and regional nodal irradiation presents a challenge in balancing the need for target coverage with avoidance of normal tissues. The novel technique termed tangential VMAT (tVMAT) utilizes beam angles tangential to the curvature of the chest wall without beams entering perpendicular to the chest wall in the direction of thoracic organs. In this study tVMAT was compared to standard 3D-conformal radiotherapy (3DCRT) in a dosimetric analysis. To our knowledge this is the first study to assess tVMAT in left-sided breast cancer patients requiring regional nodal irradiation. <h3>Materials/Methods</h3> Ten patients with left-sided breast cancer previously treated with adjuvant RT to the breast, axillary, and supraclavicular nodal regions were selected for this study. For each patient two plans were created: 1) a standard dual-isocenter three-field 3DCRT plan (two tangents and a supraclavicular field) using field-in-field dose modulation and 2) a tVMAT plan. Each tVMAT plan utilized a single isocenter for two partial arcs with angles selected to keep the central axis of the beams tangential to the curvature of the chest wall at all points. The prescription for both techniques was 5000 cGy in 25 fractions to the breast, axillary levels I-III, and supraclavicular target volumes with a goal coverage of 95% of the breast and nodal target volumes receiving at least 95% of the prescription dose. Normal tissue dose constraints were adapted from NSABP B51. Plans were created using a treatment planning system and differences in mean values for dosimetric endpoints were assessed for statistical significance using a Student's t-test (α = 0.05). <h3>Results</h3> Compared to 3DCRT plans, tVMAT provided more uniform coverage to the breast and regional lymph nodes (mean conformity index was 1.38 for tVMAT versus 2.42 for 3DCRT, <i>P</i> < 0.01) and the max point dose for tVMAT was lower on average (112.8% for tVMAT versus 121.5% for 3DCRT, <i>P</i> < 0.001). Both plans met the breast target coverage goals, however coverage to the lymph nodes was superior for tVMAT (mean coverage to 95% of the axillary plus supraclavicular target volumes was ≥ 99.0% of the prescribed dose for tVMAT versus ≥ 94.8% for 3DCRT, <i>P</i> < 0.001). Cold spots within the breast and nodal target volumes were on average lower for 3DCRT (952 cGy for 3DCRT versus 2760 cGy for tVMAT, <i>P</i> < 0.001). OAR sparing was improved with tVMAT, with a lower average V20_Gy for the left lung (16.5% for tVMAT versus 24.6% for 3DCRT, <i>P</i> < 0.01), and lower mean heart dose (168 cGy for tVMAT versus 200 cGy for 3DCRT, <i>P</i> = 0.03). <h3>Conclusion</h3> Tangential VMAT is a promising technique for the treatment of intact breast and regional lymph nodes and may provide better target coverage and OAR sparing compared to conventional 3D-conformal techniques. The use of a single isocenter for tVMAT could yield a simplified setup and more accurate treatment delivery, ideally with the use of deep inspiration breath hold or respiratory gating.

Consolidative Radiotherapy Remains a Key Player in the Salvage Management of Hodgkin Lymphoma

The role of radiotherapy following high dose chemotherapy and autologous stem cell transplantation (ASCT) for relapsed or refractory Hodgkin lymphoma (HL) has not been addressed in a prospective randomized trial. While the benefit of consolidative radiotherapy has been demonstrated in other clinical settings for HL, concern of late radiotherapy associated toxicity and uncertain treatment efficacy remain as deterrents in the peritransplant setting.We retrospectively reviewed patients with relapsed or refractory HL who underwent high dose chemotherapy and an ASCT from 2000-2019 at our institution. The association of clinicopathologic factors with the delivery of consolidative radiotherapy was assessed by Chi squared analysis. Kaplan Meier and a cox regression analysis were used to estimate factors independently associated with progression-free survival (PFS) and overall survival (OS).From 2000-2019, 179 consecutive patients underwent salvage chemotherapy (most commonly ICE: ifofsamide, carboplatin, and etoposide) followed by high dose chemotherapy (most commonly BEAM: BCNU, Etoposide, Ara-C and Melphalan) and an autologous stem cell transplant for relapsed (63.4%) or refractory (36.6%) HL with a median follow up of 59.4 months. Post-transplant consolidative radiotherapy was delivered to a median dose of 3600 cGy in 20 fractions to 72 patients (40.2%). Consolidative radiotherapy was associated with younger age (median age 32 vs. 42 years, P < 0.001), stage I-II disease at the time of salvage chemotherapy (76.4% vs 52.3%, P = 0.001), and no prior radiotherapy (76.4% vs 45.8%, P < 0.001). On univariate analysis, consolidative radiotherapy was associated with an improved two-year PFS (84.1% vs 64.1%, P = 0.005) and OS rates (95.7% vs 80.8%, P = 0.017). In the Cox regression analysis, consolidative radiotherapy was significantly associated with improved PFS (HR: 0.492, 95% CI: 0.288-0.84, P = 0.009) along with ECOG performance status < 2 (HR: 0.188, 95% CI: 0.045-0.79, P = 0.022), achieving a complete response to salvage chemotherapy (HR: 0.463, 95% CI: 0.233-0.92, P = 0.028), and stage I-II disease (HR: 0.546, 95% CI: 0.325-0.918, P = 0.022). Similarly, consolidative radiotherapy was associated with significantly improved OS (HR: 0.398, 95% CI: 0.205-0.771, P = 0.006) along with ECOG performance status < 2 (HR: 0.073, 95% CI: 0.016-0.333, P = 0.001). Following transplantation, grade ≥2 pneumonitis was identified in 10 patients (5.6%) of which only 7 patients underwent consolidative radiotherapy which was delivered to mediastinal (50.0%), supraclavicular (10.0%), or abdominal (10.0%) fields. No patient deaths were associated with pneumonitis.Our findings suggest that consolidative radiotherapy in the salvage management of HL is associated with improved PFS and OS with low rates of treatment associated complications. Further investigation in the role of consolidative radiotherapy in this setting is warranted.