Purpose: Limiting the heart dose in left sided breast cancer radiotherapy is critical. We sought to study the effect of using CPAP (continuous positive airway pressure) as an aid in reducing heart dose in breast cancer radiotherapy. Methods: Patients with left sided breast cancer receiving adjuvant radiotherapy were enrolled on a prospective IRB (institutional review board) approved clinical trial utilizing CPAP during radiotherapy. Each patient was simulated and planned with and without CPAP and the best dosimetric results determined the patient's treatment. Data on the differences in lung and heart volume and position as well as boost cavity position with and without CPAP were analyzed. Results: Twenty-four women from 10/16 to 10/18 were enrolled. Seven patients were not treated on study; only two of these were due to treatment issues. Median age was 54 years. 70% had breast only radiation and 30% were treated to breast\CW (chest wall) and regional nodes. The median lung volume with CPAP was 60% larger than without CPAP. (1637 vs. 996 cc) p < 0.001. The median heart volume decreased 12% with CPAP. (338 vs. 382 cc) In regards to the DVH, CPAP decreased mean heart dose from 3.02 to 1.6Gy (p = .0075) and V20 of the lungs from 17.1 to 13.8 with CPAP but this was not significant. Conclusion: CPAP assisted radiotherapy was tolerable and produced superior treatment plans in left sided breast cancer. This method is worthy of further investigation as a method to normal tissue sparing treatment of left sided breast cancer patients.

BackgroundSBRT is standard therapy for early stage lung cancer. Toxicity in central tumors has been a concern. RTOG 0813 showed that central SBRT is safe and effective. We report our experience with central SBRT.MethodsWe reviewed the records of patients treated with SBRT for central lung tumors (< 2 cm of the carina). Patients included primary lung cancer and recurrence following surgery and\ or conventional radiotherapy. All patients underwent 4DCT simulation and treatment planning was done with IMRT or VMAT techniques. Dose to the PTV was prescribed to the 95% isodose line.ResultsSeventy patients, between 5/09 and 4/13, were treated. Patients had early non-small cell lung cancer (n = 13) or locally recurrent lung cancer (n = 29) and pulmonary oligometastases (n = 28). Fifty-seven percent of the patients received BED of 132 with a schedule of 60Gy in 12 Gy fractions. Median follow up time was 18.3 months, 4/70 patients experienced local failure (6%). Median OS for the whole cohort was 4.6 years (CI 3-7 years). Ten patients had grade 1-2 radiation pneumonitis. One patient developed fatal bronchial bleeding.ConclusionsSBRT for central tumors is safe and effective in patients with central disease, reiradiation, recurrence following surgery and in oligometastes.

Background: Oral contraceptives (OC) and hormone replacement therapy (HRT) are well-established risk factors for ER positive breast cancer. Infertility is associated with an increased breast cancer risk and there is conflicting data on the influence of fertility treatments on breast cancer risk. The impact of exogenous estrogen exposure on breast cancer characteristics is not well described. Methods: A single center retrospective cohort study comprising all women with ER positive, human epidermal growth factor receptor 2 (HER2) negative, EBC whose tumors were sent to OncotypeDX analysis and were treated in our institute between 2005 and 2012. Data on exogenous estrogen exposure were collected including: OC and HRT use and prior fertility treatments. The impact of these exposures was assessed on pre-specified histopathological features including: tumor size, nodal status, ER and progesterone receptor (PR) staining, grade, Oncotype recurrence score (RS), ki67, lymphovascular and perineural invasion. Results: A total of 620 women were included, 79% (Num) were postmenopausal. Prior exposure to OC, HRT and fertility treatments was documented in 19% (103), 30% (136) and 11% (62), respectively. OC use was associated with smaller (≤1cm) tumors (30% vs. 20%, p=0.023) and were less likely to have grade 3 disease (10% vs. 19%, p=0.049). No other associations were found between exogenous estrogen exposures and tumor characteristics (Table). Conclusions: Use of OC may be associated with breast cancer with a distinct features compared to women with luminal breast cancer without history of OC use. Large scale studies are needed to better characterize these findings. Fertility treatmentHRT ≥ 2 yearsHRTOCPNo (%)Yes(%)PNo(%)Yes (%)PNo (%)Yes (%)PNo(%)Yes(%)0.1722254252165150.7002355222057240.7002255232456200.023205723304426T≤1 cm 1&lt;T≤2 T&gt;2 cm0.85917180.09815200.09815210.6671815Node positive0.06479138891100.29982126761590.29982135771590.207791488795IDC ILC Other0.1671864181473130.5001667181664190.5001667171762210.049186319187310Grade 1 230.18922078329680.70811781122770.70811781221780.7392227732275ER intensity≤1 1&lt;ER⇐2 ER&gt;20.1121470.67116150.67116140.103148PR Negative1.000530.455520.455530.28252PNI present0.772670.351780.351570.056105LVI present0.18620290.36222190.36223180.5282218Ki67 &gt;20%0.85917180.78718160.78717180.5701816Oncotype RS&gt;25 Citation Format: Orly Yariv, Rinat Yerushalmi, Assaf Moore, Tzippy Shohat, Ofer Rotem, Yasmin Korzets Ceder, Hadar Goldvaser. The impact of exogenous estrogen exposure on the characteristics of estrogen receptor (ER) positive, early-stage breast cancer (EBC) [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 PS8-21.