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Abstract: Background: There is assumption that omitting the internal mammary chain radiotherapy (IMC RT) in patients with breast cancer (BC) will significantly reduce the cardiac exposure for all patients regardless the cardiac anatomy of each patient. Aim: to evaluate the impact of IMC RT on the dose received by the heart and its chambers in patients with favorable versus unfavorable cardiac anatomy. Patients and methods: CT scans were obtained of 20 patients with left-sided BC, 10 with favorable and 10 with unfavorable cardiac anatomy. Three plans were generated for each patient, one treating only the breast with tangents, and one treating the breast and IMC with wide photon tangents, and one treating the breast and IMC to 50Gy with photon tangent fields and a matching medial electron field. Dose volume histograms (DVHs) were generated for the heart and chambers. The equivalent uniform doses (EUDs) were calculated for each DVH, and the mean EUDs for plans with unfavorable and favorable cardiac anatomy were compared using a two-sided two-sample T-test Results: The mean dose received by the heart from plans with tangents plus IMC fields in patients with favorable cardiac anatomy was significantly lower than that received from plans with tangents only or wide tangents in patients with unfavorable anatomy (P < .0001). The average EUD for plans with tangents and IMC fields in the favorable group was 16 Gy (SD = 4.5) as compared to 36 Gy (SD = 3.6) and 37 Gy (SD = 5.1) for plans with tangents only and wide tangents in the unfavorable group, respectively ((P < .0001). The doses to the right ventricle were not significantly different. Conclusions: Ttreatment plans should be individualized based on the cardiac anatomy of each patient. Citation Format: Mohamed Alm El-Din, Andrzej Niemierko, Alphonse Taghian. Higher radiation dose to the heart in left sided breast cancer; anatomy versus dosimetry [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 P1-10-14.

Axillary node dissection (ALND) is the standard of care for patients who have a positive sentinel lymph node (SLN) on sentinel lymph node biopsy (SLNB). We sought to identify a low-risk patient population with positive SLN that may not need cALND. We analyzed SLNB for breast cancer at our institutions between 1999 and 2007. We identified 130 patients who had a positive SLN but did not undergo completion ALND. We evaluated clinical data, adjuvant treatment patterns and intermediate locoregional and distant events. The median patient age was 50; 19% had N0(i+) disease, 53% had micrometastatic (N1mi) disease, and 28% had macrometastasis. Eighty-eight percent of patients underwent radiation therapy; 66 patients (51%) had documented nodal radiation (of these 50 were treated with three fields and 14 with high tangents. Local recurrence in the breast occurred in two patients (2%) and nine patients (7%) developed distant metastases; there were no axillary/nodal recurrences. In this highly selected group of patients who had a positive SLNB but did not undergo cALND, we observed no axillary recurrences.

Precise anatomical relationships between ducts and vasculature within the nipple remain unknown. This study investigated nipple microvessels and their position relative to ducts.Nipple and duct bundle cross-sectional areas were measured in 48 specimens. Vessels located within the central duct bundle or within a peripheral rim were counted in 7 non-irradiated and 5 irradiated nipples.Mean nipple diameter was 11.1 mm and duct bundle diameter 5.2 mm. A 2-mm and a 3-mm peripheral rim of nipple tissue would result in complete duct excision in 96% and 87% of sections, respectively. Twenty-nine percent of vessels are located in the duct bundle. A 2-mm rim contains 50%; a 3-mm rim contains 66%. Similar proportions were seen in irradiated nipples.This study describes a strategy to balance duct removal with vascular preservation. Ducts can be excised leaving a rim of nipple tissue that contains a large proportion of microvessels.

BACKGROUND It has long been known that both tumor size and the presence of malignant disease in the regional lymph nodes are indicators of outcome for patients with invasive breast carcinoma; however, the way in which these two characteristics could be integrated into an overall assessment of prognosis has not been obvious. METHODS Kaplan–Meier survival estimates (15 years) according to tumor size and lymph node status were obtained for women with invasive breast carcinoma who were observed at the University of Southern California/Van Nuys Breast Center (Van Nuys, California) or at Massachusetts General Hospital (Boston, Massachusetts). RESULTS To isolate the individual contributions to death made by tumor size and lymph node status, data were sorted according to both of these variables. For women with tumors of equivalent size, lethality increased with increasing number of positive lymph nodes, such that there was an extra ≈6% chance of death associated with each positive lymph node. For women with equivalent lymph node status, tumor size was associated with increased lethality, such that each millimeter of tumor diameter was associated with an additional ≈1% chance of death. The overall lethality was equal to the sum of the contribution from lymph node status and the contribution from tumor size, and this finding led to the creation of a new technique (the Size+Nodes method) for predicting outcome. CONCLUSIONS The Size+Nodes method was shown to be capable of accurately estimating the risk of death due to invasive breast carcinoma from information on the size of the primary tumor and the number of positive lymph nodes. In addition, this method was used to stratify women into groups according to breast carcinoma lethality. In contrast, classification of women according to lymph node positivity, T status, or disease stage created groups with wide and overlapping levels of lethality. Cancer 2003. © 2003 American Cancer Society.

BACKGROUND While the question of whether the trials of breast cancer screening have resulted in a reduction in breast cancer death has been the subject of much scrutiny, there has been less attention to the reduction in tumor size achieved by screening. METHODS Size data for invasive breast tumors were assembled from a variety of sources. The health consequences that can be expected from finding tumors of various sizes were determined using a recently developed mathematical method for relating tumor size to death rate. RESULTS First, in both the Swedish two-country trial and at the MGH Breast Imaging Division, the sizes of the invasive breast cancers in the screening population (those masses seen at screening together with those found as palpable masses after screening examinations) were sufficiently smaller than the cancers found among women who had not used screening to have lead to considerable reductions in death. Second, the lack of reduction in death rates detected in both Canadian National Breast Screening Studies could be ascribed to the small reductions in tumor size achieved in these studies. Third, radiographic density had a small effect, whereas age had a negligible effect, on the capacity of mammographic screening to find breast carcinomas at smaller, and thus less lethal, sizes. CONCLUSIONS Prompt attendance at annual mammographic screening offers the potential to reduce tumor size and, presumably, breast carcinoma death, in women of all ages and density groups. Cancer 2003. © 2003 American Cancer Society.