Radiotherapy For Breast Cancer Research Articles

Patient-reported symptoms before adjuvant locoregional radiotherapy for breast cancer: triple-negative histology impacts the symptom burden.

Multimodal breast cancer treatment may cause side effects reflected in patient-reported outcomes and/or symptom scores at the time of treatment planning for adjuvant radiotherapy. In our department, all patients have been assessed with the Edmonton Symptom Assessment System (ESAS; aquestionnaire addressing 11major symptoms and wellbeing on anumeric scale of 0-10) at the time of treatment planning since 2016. In this study, we analyzed ESAS symptom severity before locoregional radiotherapy. Retrospective review of 132 patients treated between 2016 and 2021 (all comers in breast-conserving or post-mastectomy settings, different radiotherapy fractionations) was performed. All ESAS items and the ESAS point sum were analyzed to identify subgroups with higher symptom burden and thus need for additional care measures. The biggest patient-reported issues were fatigue, pain, and sleep problems. Patients with triple negative breast cancer reported ahigher symptom burden (mean 30 versus20, p = 0.038). Patients assigned to adjuvant endocrine therapy had the lowest point sum (mean18), followed by those on Her-2-targeting agents without chemotherapy (mean19), those on chemotherapy with or without other drugs (mean26), and those without systemic therapy (mean41), p = 0.007. Those with pathologic complete response after neoadjuvant treatment had significantly lower anxiety scores (mean 0.7 versus1.8, p = 0.03) and atrend towards lower depression scores, p = 0.09. Different surgical strategies, age, and body mass index did not impact on ESAS scores, while the type of adjuvant systemic therapy did. The effect of previous neoadjuvant treatment and unfavorable tumor biology (triple negative) emerged as important factors associated with symptom burden, albeit in different domains. ESAS data may facilitate identification of patients who should be considered for additional supportive measures to alleviate specific symptoms.

Analysis of Different Treatment Methods for Breast Cancer

This research discusses the mechanisms of current medical treatments for breast cancer and a brief analysis of the treatments. The aim of this research is to present the different cancer therapies and to select the most promising and promising therapies for breast cancer based on the performance of each therapy, where chemotherapy, radiotherapy, and immunotherapy for breast cancer are discussed. By analyzing the various therapies, it is concluded that all three therapies selected for discussion have shown a significant increase in efficacy over their traditional counterparts, but at the same time, the risks and potential shortcomings of the newer therapies have been demonstrated in experimental trials. Through the analysis of this research, it is hoped that there will be a combination of techniques and breakthroughs in therapies for breast cancer. Each therapy has its own shortcomings, and the combination of chemotherapy, radiation, and immunotherapy with current cancer therapies will be the future of cancer breakthroughs.

Skin marker combined with surface-guided auto-positioning for breast DIBH radiotherapy daily initial patient setup: An optimal schedule for both accuracy and efficiency.

By employing three surface-guided radiotherapy (SGRT)-assisted positioning methods, we conducted a prospective study of patients undergoing SGRT-based deep inspiration breath-hold (DIBH) radiotherapy using a Sentine/Catalys system. The aim of this study was to optimize the initial positioning workflow of SGRT-DIBH radiotherapy for breast cancer. A total of 124 patients were divided into three groups to conduct a prospective comparative study of the setup accuracy and efficiency for the daily initial setup of SGRT-DIBH breast radiotherapy. Group A was subjected to skin marker plus SGRT verification, Group B underwent SGRT optical feedback plus auto-positioning, and Group C was subjected to skin marker plus SGRT auto-positioning. We evaluated setup accuracy and efficiency using cone-beam computed tomography (CBCT) verification data and the total setup time. In groups A, B, and C, the mean and standard deviation of the translational setup-error vectors were small, with the highest values of the three directions observed in group A (2.4±1.6, 2.9±1.8, and 2.8±2.1mm). The rotational vectors in group B (1.8±0.7°, 2.1±0.8°, and 1.8±0.7°) were significantly larger than those in groups A and C, and the Group C setup required the shortest amount of time, at 1.5±0.3min, while that of Group B took the longest time, at 2.6±0.9min. SGRT one-key calibration was found to be more suitable when followed by skin marker/tattoo and in-room laser positioning, establishing it as an optimal daily initial set-up protocol for breast DIBH radiotherapy. This modality also proved to be suitable for free-breathing breast cancer radiotherapy, and its widespread clinical use is recommended.

Abstract 4846: Geographic and physician-level variation in the use of hypofractionated radiotherapy for breast cancer in the U.S.: A cross-classified multilevel analysis

Abstract Hypofractionated whole-breast irradiation (HF-WBI), a radiotherapy with a larger dose per fraction and a shorter schedule for early-stage breast cancer patients post breast-conserving surgery, shows equivalent safety and efficacy compared to conventionally fractionated whole-breast irradiation (CF-WBI) regarding local recurrence and disease-free survival. While several countries have set HF-WBI as the preferred standard of care for these patients, its uptake in the U.S. has lagged behind expectations. We used the Health Care Cost Institute (HCCI) database 2008-2017, covering a third of the U.S. employer-sponsored insurance population, to identify early-stage breast cancer patients. Patients were clustered at different geographic levels (Census region, state, core-based statistical area (CBSA), hospital referral region of Dartmouth Atlas, and zip code) and the radiation oncologist level. These two levels are cross-nested. We used a Bayesian cross-classified multilevel logistic model to simultaneously model the geographic units variability and physician-level variability in HF-WBI use across the U.S. Variation metrics included intracluster correlation coefficient (ICC) and median odds ratios (MOR). ICC with a value of 0 is equivalent to MOR of 1, indicating identical outcomes across all levels. After accounting for these variations in the cross-classified multilevel model framework, we evaluated the association between HF-WBI use and clinical and demographic factors.Our study included 79,747 women (74.0%) who underwent CF-WBI and 27,999 (26.0%) who received HF-WBI. HF-WBI adoption increased over time (2008-2017). Variability across radiation oncologists (ICC = 0.272, MOR = 2.88) was notably larger than geographic areas variability. Variability across CBSA (ICC = 0.097, MOR = 1.76) was the strongest among all the geographic levels. The variation in HF-WBI use was mainly attributed to physician-level variability (ICC=0.222, MOR=2.59) based on the cross-classified multilevel model. No substantial differences were found between young (aged 64 or younger with commercial health plans) and older patients (aged 65 or older with Medicare Advantage plans) in terms of both geographic and physician-level variations. After accounting for variability in radiation oncologists and CBSAs, older age, non-reception of chemotherapy, and several community-level factors, including longer distance from home to facility and higher community education level, were associated with a higher likelihood of HF-WBI use. These results may lend insights into potential facilitators/barriers to HF-WBI uptake. Future studies can further investigate the impact of the 2018 American Society for Radiation Oncology (ASTRO) guideline and the Covid-19 pandemic on HF-WBI use, which would illuminate potential improvements of healthcare practices. Citation Format: Yijia Sun, Loren Saulsberry, Chuanhong Liao, Donald Hedeker, Dezheng Huo. Geographic and physician-level variation in the use of hypofractionated radiotherapy for breast cancer in the U.S.: A cross-classified multilevel analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4846.

Risk of thoracic soft tissue sarcoma after breast cancer radiotherapy: a population-based cohort study in Osaka, Japan.

Postoperative radiotherapy for breast cancer reportedly increases the risk of thoracic soft tissue sarcomas, particularly angiosarcomas; however, the risk in the Japanese population remains unknown. Therefore, this study aimed to investigate the incidence of thoracic soft tissue sarcoma among patients with breast cancer in Japan and determine its association with radiotherapy. This retrospective cohort study used data from the population-based cancer registry of the Osaka Prefecture. The inclusion criteria were female sex, age 20-84years, diagnosis of breast cancer between 1990 and 2010, no supraclavicular lymph node or distant metastasis, underwent surgery and survived for at least 1year. The primary outcome was the occurrence of thoracic soft tissue sarcomas 1year or later after breast cancer diagnosis. Among the 13 762 patients who received radiotherapy, 15 developed thoracic soft tissue sarcomas (nine angiosarcomas and six other sarcomas), with a median time of 7.7years (interquartile range, 4.0-8.6years) after breast cancer diagnosis. Among the 27 658 patients who did not receive radiotherapy, four developed thoracic soft tissue sarcomas (three angiosarcomas and one other sarcoma), with a median time of 11.6years after diagnosis. The 10-year cumulative incidence was higher in the radiotherapy cohort than in the non-radiotherapy cohort (0.087 vs. 0.0036%, P < 0.001). Poisson regression analysis revealed that radiotherapy increased the risk of thoracic soft tissue sarcoma (relative risk, 6.8; 95% confidence interval, 2.4-24.4). Thus, although rare, breast cancer radiotherapy is associated with an increased risk of thoracic soft tissue sarcoma in the Japanese population.

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.

Comparison of the effectiveness of intraoperative radiotherapy with external beam radiotherapy in patients with early breast cancer

Background. Breast cancer is the most common cancer in women. The main treatment for breast cancer includes surgery, chemotherapy, radiation therapy, and hormone therapy. The role of radiation therapy in the management of breast cancer continues to evolve. Radiation therapy is currently being de-escalated to include the use of intraoperative radiotherapy (IORT) and adjuvant endocrine therapy. Purpose of the study: to compare the efficacy of IORT with that of external beam radiotherapy (EBRT) in the treatment of early breast cancer. Material and Methods. A retrospective study of 559 patients with early breast cancer was conducted in Clinical Oncology Center of Saint Petersburg. The main treatment group included 273 patients who underwent breast-conserving surgery with IORT and sentinel lymph node biopsy. The control group included 286 patients who underwent breast-conserving surgery with sentinel lymph node biopsy and EBRT. Results. For all patients, the median follow-up time was 59.1 months (interquartile range: 43.7 to 80.7), the minimum follow-up period was 0.6 months, and the maximum follow-up period was 110.4 months. Recurrence occurred in 18 (6.6 %) patients of the main group and in 8 (2.8 %) patients of the control group. A statistically significant association of biological subtype with survival outcomes was found (p=0.02). The hazard ratio for Luminal B of 1.88 (95 % CI 1.02, 3.46) corresponded to a 65 % chance of an earlier onset of a negative outcome. The hazard ratio for triple-negative breast cancer of 3.01 (95 % CI 1.53, 5.95) corresponded to a 75 % chance of an earlier negative outcome. In the main treatment group, 11 (4 %) patients developed disease progression, and 2 of them died of multiple organ failure. In the control group, disease progression was observed in 18 (6.3 %) patients, 6 of whom died. However, the analysis of overall survival using the Kaplan–Meier curve showed a statistically non-significant log-rank p-value (0.73). The 3-year survival rates were 100 % (100 – 100) in the treatment group and 98.2 % (96.7 – 99.8) in the control group. The 5-yaer survival rates were 99.3 % (97.9 – 100) in the treatment group and 97.8 % (96.2 – 99.6) in the control group. These results showed advantage of IORT over EBRT. Conclusions. Intraoperative radiotherapy is a safe and effective alternative to external beam radiotherapy for early breast cancer.

Personalized Radiation Therapy for Breast Cancer.

Breast cancer is diagnosed in nearly 3 million people worldwide. Radiation therapy is an integral component of disease management for patients with breast cancer, and is used after breast-conserving surgery or a mastectomy to reduce the risk of a local recurrence. The following review describes the methods used to personalize radiation therapy by optimizing patient selection, using advanced treatment techniques to lessen the radiation dose to normal organs, and using hypofractionation in order to shorten the duration of radiation treatment.

Clinical practicality and patient performance for surface-guided automated VMAT gating for DIBH breast cancer radiotherapy

Background and purposeTo evaluate the performance of automated surface-guided gating for left-sided breast cancer with DIBH and VMAT. Materials and methodsPatients treated in the first year after introduction of DIBH with VMAT were retrospectively considered for analysis. With automated surface-guided gating the beam automatically switches on/off, if the surface region of interest moved in/out the gating tolerance (±3 mm, ±3°). Patients were coached to hold their breath as long as comfortably possible. Depending on the patient’s preference, patients received audio instructions during treatment delivery. Real-time positional variations of the breast/chest wall surface with respect to the reference surface were collected, for all three orthogonal directions. The durations and number of DIBHs needed to complete dose delivery, and DIBH position variations were determined. To evaluate an optimal gating window threshold, smaller tolerances of ±2.5 mm, ±2.0 mm, and ±1.5 mm were simulated. Results525 fractions from 33 patients showed that median DIBH duration was 51 s (range: 30–121 s), and median 4 DIBHs per fraction were needed to complete VMAT dose delivery. Median intra-DIBH stability and intrafractional DIBH reproducibility approximated 1.0 mm in each direction. No large differences were found between patients who preferred to perform the DIBH procedure with (n = 21) and without audio-coaching (n = 12). Simulations demonstrated that gating window tolerances could be reduced from ±3.0 mm to ±2.0 mm, without affecting beam-on status. ConclusionIndependent of the use of audio-coaching, this study demonstrates that automated surface-guided gating with DIBH and VMAT proved highly efficient. Patients’ DIBH performance far exceeded our expectations compared to earlier experiences and literature. Furthermore, gating window tolerances could be reduced.

Geographic and Physician-Level Variation in the Use of Hypofractionated Radiation Therapy for Breast Cancer in the U.S.: A Cross-Classified Multilevel Analysis

We aimed to assess geographic and physician-level variation for hypofractionated whole-breast irradiation (HF-WBI) use for early-stage breast cancer patients in the United States. We further evaluated the association between HF-WBI use and demographic factors after accounting for these variations. We performed a retrospective study of early-stage breast cancer patients using private employer-sponsored insurance claims from 2008 to 2017. Patients were clustered according to geographic level and by radiation oncologist. Bayesian cross-classified multilevel logistic models were used to examine the geographic heterogeneity and variation of radiation oncologists simultaneously. Intracluster correlation coefficient (ICC) and median odds ratios (MOR) were calculated to quantify the variation at different levels. We also used the cross-classified model to identify patient demographic factors associated with receiving HF-WBI. The study included 79,747 women (74.0%) who received conventionally fractionated whole-breast irradiation (CF-WBI) and 27,999 women (26.0%) who underwent HF-WBI. HF-WBI adoption increased significantly across time (2008-2017). The variation in HF-WBI utilization was attributed mostly to physician-level variability (MOR = 2.59). The variability of HF-WBI utilization across core-based statistical areas (CBSAs) (MOR = 1.55) was found to be the strongest among all geographic classifications. After accounting for variability in both CBSAs and radiation oncologists, age, receiving chemotherapy, and several community-level factors, including distance from home to facility, community education level, and racial composition, were found to be associated with HF-WBI utilization. This study demonstrated geographic and physician-level heterogeneity in the use of HF-WBI among early-stage breast cancer patients. HF-WBI utilization was also found to be associated with patient and community-level characteristics. Given observed physician-level variability, intervention through continuing medical education could help doctors to better understand the advantages of HF-WBI and promote the adoption of HF-WBI in the U.S. Influence of physician-level characteristics on HF-WBI utilization merits further study.

Application of fluorocarbon nanoparticles of 131I-fulvestrant as a targeted radiation drug for endocrine therapy on human breast cancer

BackgroundBreast cancer is the most prevalent malignant tumor among women, with hormone receptor-positive cases constituting 70%. Fulvestrant, an antagonist for these receptors, is utilized for advanced metastatic hormone receptor-positive breast cancer. Yet, its inhibitory effect on tumor cells is not strong, and it lacks direct cytotoxicity. Consequently, there's a significant challenge in preventing recurrence and metastasis once cancer cells develop resistance to fulvestrant.MethodTo address these challenges, we engineered tumor-targeting nanoparticles termed 131I-fulvestrant-ALA-PFP-FA-NPs. This involved labeling fulvestrant with 131I to create 131I-fulvestrant. Subsequently, we incorporated the 131I-fulvestrant and 5-aminolevulinic acid (ALA) into fluorocarbon nanoparticles with folate as the targeting agent. This design facilitates a tri-modal therapeutic approach—endocrine therapy, radiotherapy, and PDT for estrogen receptor-positive breast cancer.ResultsOur in vivo and in vitro tests showed that the drug-laden nanoparticles effectively zeroed in on tumors. This targeting efficiency was corroborated using SPECT-CT imaging, confocal microscopy, and small animal fluorescence imaging. The 131I-fulvestrant-ALA-PFP-FA-NPs maintained stability and showcased potent antitumor capabilities due to the synergism of endocrine therapy, radiotherapy, and CR-PDT. Throughout the treatment duration, we detected no notable irregularities in hematological, biochemical, or histological evaluations.ConclusionWe've pioneered a nanoparticle system loaded with radioactive isotope 131I, endocrine therapeutic agents, and a photosensitizer precursor. This system offers a combined modality of radiotherapy, endocrine treatment, and PDT for breast cancer.Graphical

Incidence of Nonkeratinocyte Skin Cancer After Breast Cancer Radiation Therapy

Previous studies have suggested that radiation therapy may contribute to an increased risk of subsequent nonkeratinocyte (ie, not squamous and basal cell) skin cancers. To test the hypothesis that radiation therapy for breast cancer increases the risk of subsequent nonkeratinocyte skin cancers, particularly when these cancers are localized to the skin of the breast or trunk. This population-based cohort study used longitudinal data from the Surveillance, Epidemiology, and End Results (SEER) Program for January 1, 2000, to December 31, 2019. The SEER database includes population-based cohort data from 17 registries. Patients with newly diagnosed breast cancer were identified and were evaluated for subsequent nonkeratinocyte skin cancer development. Data analysis was performed from January to August 2023. Radiation therapy, chemotherapy, or surgery for breast cancer. The primary outcomes were standardized incidence ratios (SIRs) for subsequent nonkeratinocyte skin cancer development from 2000 to 2019 based on treatment type (radiation therapy, chemotherapy, or surgery), skin cancer site on the body, and skin cancer subtype. Among the 875 880 patients with newly diagnosed breast cancer included in this study, 99.3% were women, 51.6% were aged older than 60 years, and 50.3% received radiation therapy. A total of 11.2% patients identified as Hispanic, 10.1% identified as non-Hispanic Black, and 69.5% identified as non-Hispanic White. From 2000 to 2019, there were 3839 patients with nonkeratinocyte skin cancer, including melanoma (3419 [89.1%]), Merkel cell carcinoma (121 [3.2%]), hemangiosarcoma (104 [2.7%]), and 32 other nonkeratinocyte skin cancers (195 [5.1%]), documented to occur after breast cancer treatment. The risk of nonkeratinocyte skin cancer diagnosis after breast cancer treatment with radiation was 57% higher (SIR, 1.57 [95% CI, 1.45-1.7]) than that of the general population when considering the most relevant site: the skin of the breast or trunk. When risk at this site was stratified by skin cancer subtype, the SIRs for melanoma and hemangiosarcoma were both statistically significant at 1.37 (95% CI, 1.25-1.49) and 27.11 (95% CI, 21.6-33.61), respectively. Receipt of radiation therapy was associated with a greater risk of nonkeratinocyte skin cancer compared with chemotherapy and surgical interventions. In this study of patients with breast cancer, an increased risk of melanoma and hemangiosarcoma after breast cancer treatment with radiation therapy was observed. Although occurrences of nonkeratinocyte skin cancers are rare, physicians should be aware of this elevated risk to help inform follow-up care.

Surface-guided radiotherapy systems in locoregional deep inspiration breath hold radiotherapy for breast cancer — a multicenter study on the setup accuracy

Surface-guided radiotherapy systems in locoregional deep inspiration breath hold radiotherapy for breast cancer — a multicenter study on the setup accuracy

Very accelerated partial breast irradiation in 1 or 2 days: Late toxicity and early oncological outcome of the GEC-ESTRO VAPBI cohort

PurposeTo analyze late toxicity after very accelerated partial breast irradiation (VAPBI) for low-risk breast cancer. MaterialsMethods: In this retrospective, observational, international multicenter study (HDH F20220713143949), patients with low-risk breast cancer underwent lumpectomy + vAPBI (high-dose rate multicatheter interstitial brachytherapy-MIBT). VAPBI was performed with 4(4x6.2 Gy/2d), 3(3x7.45 Gy/2d) or 1 fraction (1x16Gy or 1x18Gy/1d). Primary endpoint was late toxicity. Secondary endpoints were cumulative incidence of breast cancer local relapse (LR) and distant metastatic relapse (DMR) and specific (SS) and overall (OS) survivals. Prognostic factors for late toxicity were analyzed. ResultsFrom 01/2012 to 06/2022, 516 pts with early breast cancer were enrolled. Median follow-up was 44 months [95 %CI 39–46]. Median age was 71 years [40–100]. Median tumor size was 12 mm [1–35]. VAPBI delivered 1, 3 and 4 fractions for 205pts (39.7 %), 167pts (32.4 %) and 144pts (28 %) respectively. 221 late toxicity events were observed in 168pts (32.6 %) (Fibrosis, dyschromia, pain and telangiectasia). Grade 2 and 3 late toxicities were observed in 7.2 and 0.6 % respectively (no G4) with no difference between 1 and ≥ 2 treatment days. CTV > 50 cc (p = 0.007) and V150 > 40 % (p = 0.027) were prognostic factors for G ≥ 2 late toxicity. Four-year cumulative incidence rates of LR and DMR were 2 % [95 %CI 0–3] and 1 % [95 %CI 0–2] respectively. ConclusionsVAPBI based on 1 or ≥ 2 days of MIBT represents an attractive de-escalation of irradiation approach for low-risk breast cancer. Late toxicity profile appears acceptable while early oncological outcome shows encouraging local control. Longer follow-up is warranted in order to confirm these preliminary results.

151 (PB-058) Poster - Predictive factors of incidental internal mammary chain irradiation in breast cancer radiotherapy

151 (PB-058) Poster - Predictive factors of incidental internal mammary chain irradiation in breast cancer radiotherapy

Effects on Lung Tissue After Breast Cancer Radiation: Comparing Photon and Proton Therapies

PurposeIn breast cancer, improved treatment approaches that reduce injury to lung tissue and early diagnosis and intervention for lung toxicity are increasingly important in survivorship. The aims of this study are to (1) compare lung tissue radiographic changes in women treated with conventional photon radiation therapy and those treated with proton therapy (PT), (2) assess the volume of lung irradiated to 5 Gy (V5) and 20 Gy (V20) by treatment modality, and (3) quantify the effects of V5, V20, time, and smoking history on the severity of tissue radiographic changes. Patients and MethodsA prospective observational study of female breast cancer patients was conducted to monitor postradiation subclinical lung tissue radiographic changes. Repeated follow-up x-ray computed tomography scans were acquired through 2 years after treatment. In-house software was used to quantify an internally normalized measure of pulmonary tissue density change over time from the computed tomography scans, emphasizing the 6- and 12-month time points. ResultsCompared with photon therapy, PT was associated with significantly lower lung V5 and V20. Lung V20 (but not V5) correlated significantly with increased subclinical lung tissue radiographic changes 6 months after treatment, and neither correlated with lung effects at 12 months. Significant lung tissue density changes were present in photon therapy patients at 6 and 12 months but not in PT patients. Significant lung tissue density change persisted at 12 months in ever-smokers but not in never-smokers. ConclusionPatients treated with PT had significantly lower radiation exposure to the lungs and less statistically significant tissue density change, suggesting decreased injury and/or improved recovery compared to photon therapy. These findings motivate additional studies in larger, randomized, and more diverse cohorts to further investigate the contributions of treatment modality and smoking regarding the short- and long-term radiographic effects of radiation on lung tissue.

Quality of Life Outcomes Associated With Optimization of Treatment by Omitting Radiotherapy in Early Breast Cancer

PurposeImproved prognosis of early breast cancer (EBC) has created opportunities for treatment optimization but reducing morbidity should not inadvertently compromise quality of life (QoL). PROSPECT1 used pre-operative MRI and pathology findings to identify women suitable for radiotherapy (RT) omission following breast conserving surgery. We retrospectively explored the association between de-escalation by omission of RT and QoL in women with EBC. Materials and methodsThree groups were recruited: PROSPECT participants who omitted RT following preoperative MRI (A); participants who received RT following preoperative MRI (B); and women who received usual care - No MRI, received RT (C). Measures included the EORTC QLQ-C30 and BR23, BCTOS, DASS-21 and a measure of decision regret. Between group differences were assessed using ANOVA or nonparametric equivalents. Semi-structured interviews were analyzed with qualitative description (n = 44). ResultsData from 400 women were analyzed (125A, 102B, 173C). Group A had fewer symptoms and better body image (breast symptoms: A-B P = .003, A-C P = <.001; arm symptoms: A-B P = .004, A-C P = .011; body image: A-C P = .041) and fewer differences between the treated and untreated breasts (cosmetic: A-B P < .001, A-C P < .001; functional: A-C P = .011; breast specific pain: A-B P < .001, A-C P < .001). Two qualitative themes were found: Treatment with the biggest impact on QoL, and Specific impact of RT on QoL. ConclusionsOmission of RT was associated with better QoL and functional and cosmetic outcomes. It was highly acceptable to patients. Clinicians should consider the potential for preserved QoL associated with treatment optimization via omission of RT in treatment planning for patients with EBC.

143 (PB-050) Poster - MR-guided adaptive partial breast radiotherapy in low-risk breast cancer: a phase II study

143 (PB-050) Poster - MR-guided adaptive partial breast radiotherapy in low-risk breast cancer: a phase II study

23 (PB-4) Poster Spotlight - Development of an explainable AI prediction model for arm lymphoedema following breast cancer surgery and radiotherapy

23 (PB-4) Poster Spotlight - Development of an explainable AI prediction model for arm lymphoedema following breast cancer surgery and radiotherapy

Lymphocytopenia following adjuvant radiotherapy for breast cancer

AbstractObjectiveWe retrospectively analyzed breast cancer patients who received adjuvant radiotherapy to determine the incidence of lymphocytopenia and its risk factors.MethodsWe reviewed 812 patients with breast cancer who received postoperative radiotherapy. Patients were divided into two groups based on the use of chemotherapy, and a generalized linear regression model was used to explore predictive factors for grade 2 or higher lymphocytopenia. We also examined the effect of lymphocytopenia on overall survival.ResultsGrade 2 or higher lymphocytopenia was observed in 19.4% of patients who did not receive chemotherapy and 45.1% of patients who received chemotherapy. In multivariate analysis, bilateral disease, regional lymph node irradiation, and baseline lymphocytopenia were associated with lymphocytopenia in patients who did not receive cytotoxic chemotherapy. Regional lymph node irradiation, baseline lymphocytopenia, use of antimetabolites, and use of molecular‐targeted agents were associated with lymphocytopenia in patients treated with chemotherapy. In the survival analysis, lymphocytopenia was associated with worse overall survival only in patients treated with cytotoxic chemotherapy (p = 0.039), and not in patients who did not receive chemotherapy (p = 0.77).ConclusionThe analysis revealed the incidence and risk factors of lymphocytopenia after postoperative radiotherapy in patients with breast cancer.