Breast-conserving Radiation Research Articles

Radiological imaging protection: a study on imaging dose used while planning computed tomography for external radiotherapy in Japan.

Previous studies have primarily focused on quality of imaging in radiotherapy planning computed tomography (RTCT), with few investigations on imaging doses. To our knowledge, this is the first study aimed to investigate the imaging dose in RTCT to determine baseline data for establishing national diagnostic reference levels (DRLs) in Japanese institutions. A survey questionnaire was sent to domestic RT institutions between 10 October and 16 December 2021. The questionnaire items were volume computed tomography dose index (CTDIvol), dose-length product (DLP), and acquisition parameters, including use of auto exposure image control (AEC) or image-improving reconstruction option (IIRO) for brain stereotactic irradiation (brain STI), head and neck (HN) intensity-modulated radiotherapy (IMRT), lung stereotactic body radiotherapy (lung SBRT), breast-conserving radiotherapy (breast RT), and prostate IMRT protocols. Details on the use of motion-management techniques for lung SBRT were collected. Consequently, we collected 328 responses. The 75th percentiles of CTDIvol were 92, 33, 86, 23, and 32mGy and those of DLP were 2805, 1301, 2416, 930, and 1158mGy·cm for brain STI, HN IMRT, lung SBRT, breast RT, and prostate IMRT, respectively. CTDIvol and DLP values in institutions that used AEC or IIRO were lower than those without use for almost all sites. The 75th percentiles of DLP in each treatment technique for lung SBRT were 2541, 2034, 2336, and 2730mGy·cm for free breathing, breath holding, gating technique, and real-time tumor tracking technique, respectively. Our data will help in establishing DRLs for RTCT protocols, thus reducing imaging doses in Japan.

Dose and organ displacement comparisons with breast conservative radiotherapy using abdominal and thoracic deep-inspiration breath-holds: A comparative dosimetric study.

Deep-inspiration breath-hold (DIBH) reduces the radiation dose to the heart and lungs during breast radiotherapy in cancer. However, there is not enough discussion about suitable breathing methods for DIBH. Therefore, we investigated the radiation doses and organ and body surface displacement in abdominal DIBH (A-DIBH) and thoracic DIBH (T-DIBH). Free-breathing, A-DIBH, and T-DIBH computed tomography images of 100 patients were used. After contouring the targets, heart, and lungs, radiotherapy plans were created. We investigated the heart and lung doses, the associations between the heart and left lung displacements, and the thorax and abdominal surface displacements. No significant differences were observed in the target dose indices. However, the heart and lung doses were significantly lower in A-DIBH than in T-DIBH for all the indices; the mean heart and lung doses were 1.69 and 3.48 Gy, and 1.91 and 3.55 Gy in A-DIBH and T-DIBH, respectively. The inferior displacement of the heart and the left lung was more significant in A-DIBH. Therefore, inferior expansion of the heart and lungs may be responsible for the respective dose reductions. The abdominal surface displaced more than the thoracic surface in both A-DIBH and T-DIBH, and thoracic surface displacement was greater in T-DIBH than in A-DIBH. Moreover, A-DIBH can be identified because abdominal surface displacement was greater in A-DIBH than in T-DIBH. In conclusion, A-DIBH and T-DIBH could be distinguished by comparing the abdominal and thoracic surfaces of A-DIBH and T-DIBH, thereby ensuring the implementation of A-DIBH and reducing the heart and lung doses.

The Feasibility of Markerless Positioning on Breast-Conserving Radiotherapy Patients

<h3>Purpose/Objective(s)</h3> Currently, we are using a laser-based marking (LM) device to make the non-permanent reference markings for our breast radiotherapy patients. However, this method induces certain level of pain and leads to patient anxiety. Hence, we would like to investigate the possibilities of markerless positioning using our newly installed surface guided (SG) system. <h3>Materials/Methods</h3> 40 breast intact radiotherapy patients, who were treated between July 2021 to January 2022, were studied retrospectively. Firstly, the patient was aligned based on the three laser-based markings at the isocenter plane. The couch parameters (Data A) were recorded. Next, the patient was fine-tuned based on SG system to less than 1 mm and 1 degree and couch parameters (Data B) were recorded. Following by the CBCT, the image matching was done, and shifts were applied accordingly. Lastly, the final couch parameters (Data C) were recorded. All couch parameters were recorded in x, y and z axes. CBCTs were performed for the first three fractions and subsequently once a week across all the patients. The differences between Data B and Data C were identified as SG setup errors and the differences between Data A and Data C were identified as LM setup errors. Paired sample t-test was performed to compare the means between LM and SG positioning methods. P < 0.05 was considered as statistically significant. Bland-Altman plot was used to analyze the consistency between SG system and CBCT. <h3>Results</h3> The setup errors using LM and SG positioning were (0.20±0.12) cm, (0.25±0.18) cm, (0.37±0.24) cm and (0.11± 0.05) cm, (0.15±0.06) cm, (0.17±0.06) cm in x, y and z axes respectively. The systematic errors using SG positioning were significantly reduced (p <0.05) by 0.09cm, 0.1cm and 0.2cm in x, y and z axes. In addition, the absolute setup errors were all within 0.3cm in all directions. The setup accuracy using SG positioning was improved by 14.8%, 16.3% and 35.1% compared to LM positioning, in x, y and z directions. In bland-Altman scatter plot, 95% limits of agreement of x, y and z translation directions were (-0.30∼0.35), (-0.38∼0.40) and (-0.24∼0.48) cm respectively. Within the limits of agreement, the maximum absolute value of the difference was 0.3cm, 0.4cm, 0.4cm, respectively, and it was clinically acceptable. <h3>Conclusion</h3> The implementation of SG system in the breast intact radiotherapy workflow can improve the setup accuracy and making markerless positioning feasible. Furthermore, the strong correlation between SG and CBCT could potentially reduce the use of CBCT.

Abstract P3-18-02: Breast conservation plus radiotherapy provides superior survival benefit than mastectomy in triple negative breast cancer: A propensity matched national cancer database analysis

Abstract Background: Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype with a higher risk of locoregional and distance recurrence. Consequently, this population was considered poor candidate for breast conservation (BCT). Our study aim was to determine whether BCT plus radiotherapy (RT) was equivalent to mastectomy for TNBC after adjustment of selection bias of demographic and clinical characteristics. Methods: The National Cancer Database was queried for women diagnosed as primary unilateral invasive clinical T1-2N0-2 TNBC from 2004-2016. Patients who underwent mastectomy or breast conservation (partial mastectomy plus radiation) were included. A 1:1 propensity match with replacement was performed to compare breast conservation vs. mastectomy. Overall survival was analyzed using stratified multivariable Cox proportional hazard regression analysis.Results: Of 59,599 clinical T1-2N0-2 TNBC patients, 26,325 (44.2%) underwent mastectomy and 33,274 (55.8%) were treated with BCT. BCT patients were older (median age 59 vs. 54, p&amp;lt;0.001), had smaller tumors (cT1 61.7% vs. 42.9%, p&amp;lt;0.001) and node negative (cN0 85.8% vs. 73.7%, p&amp;lt;0.001). Propensity matching reduced the bias between mastectomy and breast conservation groups and generated 30,980 pairs for analysis. Median follow-up times were 41 months (range 6.97-95.8) and 39 months (range, 0.62 -94.06) for BCT and mastectomy groups, respectively. After matching, BCT+RT was associated with significantly higher OS compared to mastectomy ( 86.8% vs. 79.7%, p&amp;lt;0.001). The survival advantage was also present in multivariate cox regression after controlling age, race, insurance, facility type, clinical T and clinical N stage.Conclusions: Using both propensity matching and multivariate cox regression controlling for potential confounders, BCT+RT survival was superior to mastectomy in a retrospective analysis of a large cancer database. Citation Format: Lifen Cao, Christopher W Towe, Megan E Miller, Alberto J Montero, Robert Shenk. Breast conservation plus radiotherapy provides superior survival benefit than mastectomy in triple negative breast cancer: A propensity matched national cancer database analysis [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-18-02.

Breast Cancer in Chinese Females Aged 25 Years and Younger.

Background Breast cancer has both aggressive clinicopathological characteristics and a poor prognosis in young females. However, limited information is available for breast cancer in Chinese females aged ≤25 years. Therefore, we aimed to explore prognostic factors for invasive disease-free (iDFS) and overall survival (OS) among breast cancer patients aged ≤25 years. Methods We retrospectively analyzed data from 174 Chinese females aged ≤25 years with invasive breast cancer treated in the Cancer Hospital of the Chinese Academy of Medical Sciences from January 1, 1999, to December 31, 2018. Univariate and multivariate Cox regression analyses were performed to identify independent prognostic factors. Results The median follow-up time was 75 months (ranging from 1 to 236 months). Breast cancer patients aged ≤25 years exhibited aggressive clinicopathological characteristics, including advanced tumor stage (21.8%), lymph node metastasis (47.1%), lymphovascular invasion (24.1%), estrogen receptor negativity (44.3%), progesterone receptor (PR) negativity (42.5%), and triple-negative breast cancer (25.3%). Among them, 50 cases had locoregional recurrence and metastasis, 20 had bilateral invasiveness, and 33 had breast cancer-specific deaths. Cox multivariate analysis identified that diagnosis delay, PR status, and radiotherapy were significant prognostic factors for both iDFS and OS (P < 0.05). The risk of recurrence and metastasis was five times higher in N3 than in N0 (HR: 6.778, 95% CI: 2.268–17.141, P < 0.001). Patients with lymphovascular invasion had a threefold increase in the risk of breast cancer-specific death (HR: 4.217, 95% CI: 1.956–9.090, P < 0.001). No differences were observed between mastectomy and breast-conserving surgery (BCS) plus radiotherapy for iDFS or OS (iDFS: χ2 = 0.678, P=0.410; OS: χ2 = 0.165, P=0.685). Conclusions Breast cancer in females ≤25 years old was associated with aggressive clinical features and a worse prognosis. Young females with breast lumps should receive timely diagnosis and treatment. Young breast cancer patients with lymphovascular invasion, PR-negative status, and lymph node metastasis have an increased risk of experiencing recurrence and metastasis and should hence be closely monitored. Age at diagnosis should not be the sole deciding factor for surgical treatment methods.

Automatic Segmentation of Clinical Target Volume and Organs-at-Risk for Breast Conservative Radiotherapy Using a Convolutional Neural Network.

ObjectiveDelineation of clinical target volume (CTV) and organs at risk (OARs) is important for radiotherapy but is time-consuming. We trained and evaluated a U-ResNet model to provide fast and consistent auto-segmentation.MethodsWe collected 160 patients’ CT scans with breast cancer who underwent breast-conserving surgery (BCS) and were treated with radiotherapy. CTV and OARs were delineated manually and were used for model training. The dice similarity coefficient (DSC) and 95th percentile Hausdorff distance (95HD) were used to assess the performance of our model. CTV and OARs were randomly selected as ground truth (GT) masks, and artificial intelligence (AI) masks were generated by the proposed model. Two clinicians randomly compared CTV score differences of the contour. The consistency between two clinicians was tested. Time cost for auto-delineation was evaluated.ResultsThe mean DSC values of the proposed method were 0.94, 0.95, 0.94, 0.96, 0.96 and 0.93 for breast CTV, contralateral breast, heart, right lung, left lung and spinal cord, respectively. The mean 95HD values were 4.31mm, 3.59mm, 4.86mm, 3.18mm, 2.79mm and 4.37mm for the above structures, respectively. The average CTV scores for AI and GT were 2.89 versus 2.92 when evaluated by oncologist A (P=0.612), and 2.75 versus 2.83 by oncologist B (P=0.213), with no statistically significant differences. The consistency between two clinicians was poor (kappa=0.282). The time for auto-segmentation of CTV and OARs was 10.03 s.ConclusionOur proposed model (U-ResNet) can improve the efficiency and accuracy of delineation compared with U-Net, performing equally well with the segmentation generated by oncologists.

The Impact of Different Simulation Modalities on Target Volume Delineation in Breast-Conserving Radiotherapy.

PurposeIn the management of breast-conserving radiotherapy, computed tomography (CT) simulation is now commonly used to identify tumor bed while has difficulties defining precisely. We aimed to evaluate the impact of magnetic resonance (MR) and CT simulation on defining the postoperative tumor bed for breast-conserving radiotherapy in patients without the aid of surgical clips.MethodsFrom August 2018 to March 2019, twenty patients with T1-2N0M0 breast cancer at our institution were enrolled. All the patients underwent breast-conserving surgery without implantation of surgical clips and were prepared to receive radiotherapy. CT and MR images were acquired on the same day for each patient. Three radiation oncologists independently assigned cavity visualization score (CVS) and delineated the tumor bed based on first the CT then the MR images. Interobserver variability was assessed by volumes, generalized conformity index (CIgen) and the distance between the centers of mass (dCOM). Differences in mean values for parameters were tested by paired t-test or one-way analysis of variance, as appropriate.ResultsFirst, the mean volumes of tumor bed derived from MR were 22%, 27% and 21% smaller than those based on CT images for each observer. In addition, the mean CIgen was significantly superior, and dCOM was smaller for MR than for CT images (CIgen: 0.59 vs 0.52, P= 0.008; dCOM: 1.30 cm vs 1.39 cm, P= 0.095). Moreover, the mean CVS was 3.23±1.34 and 2.43±0.92 for MR and CT images, respectively (P= 0.035). Last, a positive association was observed between the CVS and CIgen for both modalities (P< 0.01).ConclusionCompared to CT, MR can improve the visualization of changes in the postoperative tumor bed. In addition, MR can yield a more precise definition of the tumor bed and improve the consistency of tumor bed contouring in patients without surgical clips.

Effect of auto flash margin on superficial dose in breast conserving radiotherapy for breast cancer.

PurposeTo investigate the dose‐effect of Auto Flash Margin (AFM) on breast cancer's superficial tissues based on the Treatment Planning System (TPS) in the breast‐conserving radiotherapy plan.MethodsA total of 16 breast‐conserving patients with early stage breast cancer were selected, using the X‐ray Voxel Monte Carlo (XVMC) algorithm. Then, every included case plan was designed using a 2 cm‐AFM (the value of AFM is 2 cm) and N‐AFM (without AFM). Under the condition of ensuring the same configuration of #MU and collimator, the absorbed dose after a simulated inspiratory motion was calculated again using the new plan center, which moved backward to the linac source. The dose difference between the measurement points between AFM and N‐AFM groups was compared.ResultsIn the dose results, PTVV50Gy of the AFM group was superior to that of the N‐AFM group, PTVD2%, PTVDmean, Lung_IpsiV20Gy, Lung_IpsiDmean, and BodyDmax. Also, the dose results of the N‐AFM group were significantly higher than those of the AFM group. However, there was no significant difference between Lung_ContraV5Gy, HeartDmean, and Breast_ContraV10Gy in the two groups. In the collimator alignments at the same angle between groups, the AFM group formed an apparent air region outside the collimator compared with the N‐AFM group. In the XVMC algorithm feature parameter, the AFM group had less #MU, higher QE, and slightly longer optimization time. The #segments of both groups were close to the 240 control points preset by the plan. The validation results of EBT3 film in both groups were more significant than 95%, meeting the clinical plan's application requirements. The difference in film results between groups was mainly reflected in the dose distribution at the near‐source. 4DCT was used to summarize the maximum and minimum inspiratory motion distances of 7.31 ± 0.45 and 3.42 ± 0.91 mm respectively.ConclusionsThese results suggest that the AFM function application could significantly reduce the possibility of insufficient tumor target caused by inspiratory motion and ensure sufficient tumor target exposure.

Abstract PS7-13: Associations between frailty and cancer-specific mortality among older women with breast cancer

Abstract PURPOSE Frailty is assessed when making treatment decisions among older women with breast cancer (BC), which in turn impacts survival. We evaluated associations between frailty and risks of BC-specific and all-cause mortality in older women. METHODS We conducted a retrospective cohort study of Medicare beneficiaries ages ≥65 years with stage I-III BC using the Surveillance, Epidemiology and End Results Medicare Health Outcome Survey Data Resource. Frailty was measured using the deficit-accumulation frailty index, categorized as robust, pre-frail or frail, at baseline and during follow-up. Fine and Gray competing risk and Cox proportional hazards models were used to estimate sub-distribution hazard ratios (SHR) and hazard ratios (HR) with 95% confidence intervals (CI) for BC-specific and all-cause mortality, respectively. RESULTS Among 2,411 women with a median age of 75 years at BC diagnosis, 50% were categorized as robust, 29% were pre-frail and 21% were frail. Compared to robust women, fewer frail women received breast-conserving surgery (52% vs. 63%) and radiation (44% vs. 52%). In multivariable analyses, frail women had higher risks of all-cause mortality compared to robust women (HR 2.16, 95% CI 1.80-2.60). CONCLUSION Frail women in our study had a higher cumulative hazard of BC-specific death, but this observed higher risk was not significant after accounting for differences in treatment and competing risks of other-cause death. Measuring frailty may help determine overall life expectancy but not BC-specific death. Table. Risk of Breast Cancer-Specific and All-cause Mortality, using time-varying DAFI measureEventsCrude SHRRobust 95%CIP-valueMinimally Adjusted SHRaRobust 95%CIP-valueFully Adjusted SHRbRobust 95%CIP-valueBreast Cancer-Specific MortalityDAFI CategoriesRobust891.001.001.00Pre-frail691.250.91 – 1.700.161.150.84 – 1.590.381.060.77 – 1.480.72Frail621.531.11 – 2.110.011.371.00 – 1.900.051.190.85 – 1.660.31All-Cause MortalityDAFI CategoriesRobust2721.001.001.00Pre-frail2241.551.30 – 1.84&amp;lt;0.00011.411.19 – 1.68&amp;lt;0.00011.371.15 – 1.63&amp;lt;0.0001Frail2362.32.12 – 3.02&amp;lt;0.00012.331.96 – 2.78&amp;lt;0.00012.161.80 – 2.60&amp;lt;0.0001DAFI = deficit-accumulation frailty index; HR = hazard ratio; SHR = subdistribution hazard ratios; CI = confidence intervalsa adjusted for age categories and breast cancer staging b adjusted for age categories, breast cancer staging, surgery type, radiation, Estrogen/Progestin Receptor, race/ethnicity, marital status, and education Citation Format: Connie H Yan, Chandler Coleman, Nadia A Nabulsi, Brian Chiu, Naomi Y Ko, Kent Hoskins, Gregory S Calip. Associations between frailty and cancer-specific mortality among older women with breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS7-13.

Radiation Therapy in the Hispanic Breast Cancer Population: An Analysis of Patient Demographics and the Impact of Insurance Status on Rates of Breast Conserving Radiation Therapy.

Disparities in minority healthcare include lower rates of insurance coverage and increased morbidity and mortality from cancer. We sought to evaluate the demographics of our Hispanic breast cancer population and evaluate the impact of insurance status on rates of breast conserving radiation therapy (BCT) including whole breast radiation (WBRT) and accelerated partial breast irradiation (APBI) versus postmastectomy radiation therapy (PMRT). We performed a retrospective review of 120 women with invasive and non-invasive breast cancer receiving curative RT between the dates of January 2017 through June 2019. Women identifying as Hispanic and all women from Latin America were included. BCT included WBRT with 3D-conformal RT (3D-CRT) and APBI with either 1. 3D-CRT or 2. HDR 192Ir brachytherapy interstitial catheters or surface applicators. We defined insurance status as 1. Insured, 2. Medicaid and 3. Non-insured. Additional patient demographics including age, BMI, country of birth, and anatomical stage were reviewed. Multivariable logistic regression model was used to evaluate odds ratios for primary outcome of WBRT/APBI as a BCT event vs. PMRT. 70 Hispanic women were identified for analysis. Median age, insurance status and cancer stage are listed (Table 1). The median BMI was 29.7 (22.0, 45.3) and median age was 58.5 (33.0, 81.0). The median BMI was non-significant but slightly lower in PMRT group (29.7 vs. 30, p-value = 0.82). Multivariable model was constituted with variable: age, BMI, primary insurance, anatomic stage, and country/region of birth (USA, Caribbean, and South/Central America). There were 58 BCT events (49 WBRT and 9 APBI) which explains enough power to construction of multivariable model. In a multivariable model, the insured subjects had 17.5 times higher odds of opting for WBRT/APBI BCT [OR (95% CI) = 17.53 (1.69, 432.0)] compared to non-insured subjects which was statistically significant (p = 0.036). This association was significant [OR (95% CI) = 6.36 (1.44, 34.37), p = 0.019] in a single variable model with more than 6 times higher odds. All other associations in the multivariable model were not statistically significant. Hispanic women comprise the majority of breast cancer patients treated at our community hospital with 83% receiving BCT versus PMRT. Insured status was a significant predictor of BCT with the insured population having an almost 18-fold higher rate of receiving WBRT or APBI than the non- insured population (OR = 17.53). Although this is a single institution study and limited by a small PMRT sample size, this health care disparity warrants further investigation to better understand access to care and barriers to BCT in the Hispanic population.Tabled 1Abstract 2925; TableWBRT/APBI n = 58PMRT n = 12All n = 70Age59.553.558.5Insured35338Medicaid12315Non-insured11617Stage 010010Stage I27027Stage II181028Stage III325 Open table in a new tab

Comparison of Magnetic Resonance Imaging and Computed Tomography–Based Volume Delineation of Lumpectomy Cavity Without Surgical Clips in Breast-Conserving Radiotherapy

First, to compare magnetic resonance (MR) imaging and computed tomography (CT) -based definition of lumpectomy cavity in patients without surgical clips. Second, to quantify consistency of MR and CT-based lumpectomy cavity delineation for breast-conserving radiotherapy. Between August 2018 and March 2019, twenty patients with T1-2N0M0 breast cancer at our institution were enrolled in this study. All the patients had been treated by breast-conserving surgery without implantation of surgical clips, and prepared to receive radiotherapy. MR and CT images were required in the same day for each patient. Three radiation oncologists independently assigned cavity visualization score (CVS), and delineated the lumpectomy cavity based on CT then on MR images with a 14-day interval for each patient. Interobserver variability was assessed by volumes, generalized conformity index (CIgen) and the distance between the centers of mass (dCOM). Differences in means were tested by the paired sample t-test or One-way analysis of variance, as appropriate. The median age of included patients was 48 years old (range, 33-73). Mean volumes of lumpectomy cavity derived from MR were 22%, 27% and 21% smaller than those based on CT images for each radiation oncologist. And mean CVS was 2.43±0.92 and 3.23±1.34 for CT and MR scans (P = 0.035). In addition, mean CIgen was significantly superior and dCOM was closer for MR when compared to CT (CIgen: 0.59 vs 0.52, P = 0.008; dCOM: 1.30 cm vs 1.39 cm, P = 0.095). In the subgroup with a CVS≥3, the mean dCOM was also obviously larger obtained from CT than those from the MR images (1.35 cm vs 1.19 cm, P = 0.048). A positive association was observed between CVS and CIgen for CT and MR, while CVS was negatively correlated with dCOM for MR images (both P <0.001). In the present study, when compared to CT, MR was able to improve the visualization of postoperative lumpectomy cavity changes. In addition, MR yielded a more precise definition of lumpectomy cavity and improved the consistency of lumpectomy cavity delineation in patients without the aid of surgical clips.

47: Five Year Longitudinal Analysis of Myocardial Perfusion Scintigraphy Post Radiotherapy Using Single-Photon Emission Computed Tomography (Spect) Prospective Comparison of Long Term Cardiac Function of Patients Participated in a Phase Iii Randomized Study of Breast Conserving Surgery and Radiotherapy

47: Five Year Longitudinal Analysis of Myocardial Perfusion Scintigraphy Post Radiotherapy Using Single-Photon Emission Computed Tomography (Spect) Prospective Comparison of Long Term Cardiac Function of Patients Participated in a Phase Iii Randomized Study of Breast Conserving Surgery and Radiotherapy

Ductal Carcinoma In Situ of the Breast: Perspectives on Tumor Subtype and Treatment.

Objective To evaluate ductal carcinoma in situ (DCIS) characteristics and the effect of different treatment strategies. Patients and Methods. Using data with known hormone receptor (HoR) and human epidermal growth factor receptor 2 (HER2) status obtained by the Surveillance, Epidemiology, and End Results (SEER) program from 2010-2014, the study was conducted to investigate tumor subtype-specific differences in various characteristics, overall survival (OS), and breast cancer-specific mortality (BCSM). Results A total of 3415 patients with DCIS were eligible. Compared with HoR+/HER- subgroup, patients with triple-negative (TN) and HoR-/HER+ were commonly higher in grade, larger in size, and tended to receive mastectomy (P < 0.05). The multivariate analysis revealed that patients with TN were more likely to have a poorer OS and show a higher breast cancer-specific mortality compared with the HoR+/HER- subgroup (P < 0.05). Multivariate analysis on the history of local treatment and surgery showed patients receiving breast-conserving surgery (BCS) plus radiotherapy (R) and BCS plus axillary lymph node dissection was likely to improve OS without affecting breast cancer-specific mortality (P < 0.05). Conclusion The results demonstrate that DCIS associated with TN subtype portends poor prognosis. Meanwhile, BCS plus R was a preferable option and resulted in survival rates better than those achieved with mastectomy, and SLNB should be considered as an appropriate assessment of axillary staging in patients with DCIS.

Breast cancer in women aged 80 years and older: Clinical characteristics and treatment patterns according to biologic subtype.

e12594 Background: Older age is associated with poorer breast cancer-specific survival (BCSS) outcomes, despite a higher prevalence of biologically favorable disease. We sought to evaluate differences in the clinical characteristics and management of older women according to biologic subtype of breast cancer. Methods: The Surveillance, Epidemiology, and End Results (SEER) treatment database was queried to identify all women aged 80 years or older with a first diagnosis of invasive breast cancer between 2010 and 2016. Patients were subgrouped according to biologic subtype and clinical and treatment-related variables were compared. Multivariable logistic regression was then performed to determine factors independently associated with receipt of breast-conserving surgery (BCS) and adjuvant radiation. Results: Overall, 27,375 women with a median age of 84 (range, 80-108 years) met inclusion criteria. The majority of older women were diagnosed with HR+HER2- breast cancer (78.9%), followed by HER2+ (11.0%) and triple-negative breast cancer (TNBC) (10.0%). In women with stage I-III disease, non-operative management was employed in 13.4% of HR+HER2- patients, compared to 16.7% of HER2+ patients and 11.0% of TNBC (p &lt; 0.001). In those undergoing surgery, BCS was most common in HR+HER2- patients (80.9%), compared to HER2+ (68.9%) and TNBC (67.8%; p &lt; 0.001). Axillary surgery was performed in 74.0% of early stage patients with HR+HER2- disease, compared to patients with HER2+ (77.8%) and TNBC (79.3%; p &lt; 0.001). In adjusted analyses controlling for stage and clinical variables, women aged 80 years or older with HER2+ breast cancer and TNBC had a lower likelihood of BCS (ORHER2+ 0.72, 95% CI 0.65-0.80; ORTNBC 0.72, 95% CI 0.65-0.81), and an increased likelihood of adjuvant radiation (ORHER2+ 1.14, 95% CI 1.02-1.27; ORTNBC 1.40, 95% CI 1.25-1.57). Conclusions: One fifth of women with breast cancer over age 80 are diagnosed with HER2+ and triple-negative subtypes, which are associated with more aggressive local therapy. Further studies are warranted to determine if higher rates of adjuvant radiation optimize local control in older HER2+ and TNBC patients at increased risk for early locoregional recurrences.

Evaluation of left ventricular systolic function and synchrony in patiests with early left breast cancer after breast conserving radiotherapy by layer-specific strain technique

Objective To evaluate the left ventricular systolic function and synchronization of patients with early left breast cancer after breast conserving radiotherapy by layer-specific strain technique. Methods Thirty-six patients with early left breast cancer who underwent breast surgery and radiotheraphy in Affiliated Tumor Hospital of Zhengzhou University from January 2018 to January 2019 were selected for this study. The layered strain technique was respectively applied to collect two-dimensional dynamic ultrasonic cardiograms one week before radiotherapy, one week after radiotherapy, and six months after radiotherapy. The EchoPAC 201 software was applied to analyze and obtain the global longitudinal peak strain(GLPS) and peak stain dispersion(PSD) of the epicardial layer(epi), the middle layer(mid) and endocardial layer(endo) of 17 left ventricular segments. The differences of every parameter before and after radiotherapy were compared, and the correlation of PSD and other parameters was analyzed. Results Compared with one week before radiotherapy, the absolute values of LPSepi, LPSmid, LPSendo, and GLPS all reduced significantly one week and six months after radiotherapy, and PSD increased significantly (P<0.05). Compared with one week after radiotherapy, the LPS absolute value of every layer and GLPS obviously reduced after six months, PSD obviously increased, the difference had statistical significance (P<0.05). PSD and GLPS displayed negative correlation one week after radiotherapy (r=-0.420, P<0.05), PSD and GLPS displayed negative correlation six months after radiotherapy (r=-0.641, P<0.05). Conclusions Layered strain technique can noninvasively and quantitatively evaluate the early changes of global and layered longitudinal peak strain and systolic synchrony of left ventricle in left breast cancer breast-conserving radiotherapy patients, and provides a new noninvasive test method for evaluating radioactive myocardial injury, and it has a certain guiding value to early clinical intervention and treatment of cardiovascular complications. Key words: Breast cancer, early; Radiotherapy; Layer-specific strain; Peak strain dispersion

Esthetic outcomes of using latissimus dorsi flap for breast reconstruction after breast-conserving surgery

Background Lesion location and the volume of breast excised in correlation to the total breast volume are cornerstone issues in oncoplastic surgery after surgical breast-conserving surgery affecting the esthetic management plan and protocol implemented. Aim of the study Verifying the value of using latissimus dorsi (LD) myocutaneous flaps in secondary breast reconstruction after surgical breast conservation. Patients and methods A total of 73 cases that have undergone unilateral surgical breast conservation and postoperative radiotherapy, subsequently followed by secondary reconstruction of the breast using the latissmus dorsi as a myocutaneous flap at Ain Shams University Hospital and Bahya Hospital of Breast Cancer between January 2015 and January 2018. Results Binary logistic regression statistical analysis have shown that preoperative overall esthetic score was the only significant predictor of having postoperative excellent/very good esthetic score (P Conclusion The current research study verifies the usefulness of LD flap in the restoration of adequate esthetic outcomes required after surgical conservative manner of breast tumor removal; however racial, ethnic, and anatomical differences should be considered in future research

Effect of intraoperative radiotherapy for early breast cancer on 10-year recurrence rates and overall survival.

The aim of this study was to evaluate 10-year local control and overall survival of IORT for early breast cancer treatment. We analyzed 68 patients submitted to breast conservative surgery and IORT, in the accelerator room of the Radiotherapy Service in South Brazil. In the long-term follow-up, we had 17.6% of patients with ipsilateral breast cancer recurrence, 2.9% with regional recurrence, 2.9% with contralateral breast recurrence, and 5.9% with distant metastasis. The 10-year overall survival was 82.8%. Our data show high local recurrence rates, however, good overall survival in early breast cancer patients treated with breast-conserving surgery and intraoperative radiotherapy with electron beams in the long-term follow-up.

Effects of regular bra-wearing on acute skin toxicity in breast-conserving radiotherapy women

Purpose: To evaluate the effects of regular bra-wearing during radiotherapy on acute skin toxicity (AST) and the Quality of Life (QOL) in women with breast conserving therapy (BCT). Methods: A prospective study of 99 patients with any stage of breast cancer who underwent BCT. Patients were instructed to wear an appropriate bra then they were classified by total hours of wearing bra during the radiotherapy treatment course into Non-Bra-Wearing (NBW) (0 hr.) and Bra-Wearing (BW) groups (&gt;0 hr.). The AST was assessed weekly and one week after treatment end by CTCAE v 4.03. The QOL was assessed before and one week after treatment end by The Functional Assessment of Cancer Therapy-Breast Cancer (FACT-B) Thai version 4. Results: 66 patients were in the BW group and 33 patients were in the NBW group. The rate of ≥ G2 AST was lower in the BW group compared to the NBW group (16.7% vs. 54.5%, p&lt;0.001, respectively). In the multivariate analysis, the statistically significant factors that were associated with increased the risk of ≥ G2 AST were NBW (0 hr.) (p&lt;0.001), high body mass index (p=0.001), and high percentage of maximum dose (p=0.043). There was no differences in all parts of after treatment FACT-B between the two groups (118.4 vs. 114.7, p=0.256, respectively). Conclusions: Regular BW during radiotherapy is not associated with increased risk of ≥ G2 acute skin toxicity and does not affect the QOL compared to NBW.

Breast-Conserving Radiotherapy with Simultaneous Integrated Boost—A Dosimetric Comparison of 3DCRT, VMAT and IMRT: Do We Really have a Better Plan?

The availability of more advanced technology like hypo-fractionation has the potential of being the new standard of care in breast cancer. This study evaluates whether 3DCRT with a field-in-field technique (FIF) and a simultaneous integrated boost (SIB) could provide a dosimetrically comparable plan delivered to VMAT or IMRT. 3DCRT-FIF-SIB, VMAT and IMRT-SIB plans were generated for 20 patients. The plans were compared for planning target volume coverage (PTV 95), homogeneity and conformity, dose delivered to lungs, heart and C/L breast. 3DCRT FIF provided better sparing of C/L breast V1 and V5, whole lung V5, p = 0.000. The VMAT plans spared heart V30: (0.1 ± 0.46 vs. 11.5 ± 18.3) p = 0.000 and I/L lung V20: (19.3 ± 5 vs. 32.2 ± 11.1) p = 0.000. It provided a better coverage V95: (97 ± 0.8 vs. 95 ± 2.9) p = 0.002 and sparing of the heart V30: (0.1 ± 0.5 vs. 8.6 ± 11.5) p < 0.002 and lungs I/L V20: (19.3 ± 5.0 vs. 30.7 ± 6.1) p = 0.000. The treatment was faster with less exposure in terms of MU: (529 ± 57.8 vs. 1024 ± 298) p = 0.000. 3DCRT provides a dosimetrically acceptable alternative to more advanced technologies. VMAT and IMRT provide better sparing of heart and lungs. VMAT has a slight benefit of conformity, reduced exposure and shorter treatment time.

EP-1271 Effects of regular bra-wearing on acute skin toxicity in breast-conserving radiotherapy women

EP-1271 Effects of regular bra-wearing on acute skin toxicity in breast-conserving radiotherapy women