Lợi ích xạ trị ung thư vú trái phối hợp hít sâu nín thở và hệ thống quản lý bề mặt quang học của máy Truebeam tại Bệnh viện Ung bướu Thành phố Hồ Chí Minh

TÓM TẮT Đối với ung thư vú (UTV) xạ trị là điều trị bổ túc cần thiết giúp giảm tái phát tại chỗ tại vùng, gia tăng sống còn. Tuy nhiên, xạ trị có tác dụng phụ lên tim mạch nhất là với UTV trái. Nhiều nghiên cứu đã chứng minh biến chứng và tử vong do tim mạch tăng tỉ lệ thuận với liều trung bình lên tim. Các kỹ thuật xạ trị mới trong xạ trị ung thư vú trái giúp tối ưu hóa liều vào thể tích xạ và bảo vệ tốt hơn cơ quan lành, càng đòi hỏi độ chính xác cao khi đặt bệnh. Các sai số do thiết bị hoặc đặt bệnh sẽ dẫn đến nguy cơ quá liều dung nạp hoặc thiếu liều và có nguy cơ tái phát. Vì vậy, xạ trị đòi hỏi sự chính xác cao trong suốt quá trình từ mô phỏng đến lập kế hoạch và tiến hành xạ trị. Xạ trị ung thư vú trái phối hợp hít sâu nín thở (DIBH - Deep Inspiration Breath - hold) và hệ thống quản lý bề mặt quang học (OSMS - Optical Surface Management System) làm cho tim di chuyển ra xa hơn khỏi vú, thành ngực trong quá trình xạ trị, giúp giảm liều tim một cách rõ rệt, vẫn đảm bảo được liều xạ lên thể tích đích. Ưu điểm của OSMS ngoài áp dụng cho đặt bệnh nhanh không cần xăm dấu trên da còn giám sát thời gian thực trong toàn bộ quá trình điều trị. Khi nhịp thở của bệnh nhân vượt quá một ngưỡng nhất định (0,3cm) chùm tia bức xạ sẽ bị tắt để ngăn ngừa độc tính. Do đó, hiểu và nắm rõ lợi ích quy trình đặt bệnh giúp đạt mục tiêu điều trị đồng thời giảm thời gian đặt bệnh để người bệnh có tâm lý thoải mái hơn, giảm áp lực về số lượng bệnh, nhất là đối với các trung tâm xạ trị lớn. ABSTRACT BENEFITS OF LEFT BREAST CANCER RADIATION COMBINATION OF DEEP INSPIRATION BREATH - HOLD AND OPTICAL SURFACE MANAGEMENT SYSTEM OF TRUEBEAM MACHINE AT CANCER HOSPITAL HO CHI MINH CITY Background: For breast cancer, radiation therapy is an essential adjuvant treatment to help reduce local recurrence and increase survival. However, radiation therapy has adverse effects on the cardiovascular systemespecially for left breast cancer. Several studies have demonstrated that cardiovascular morbidity and mortality increase in proportion to the mean cardiac dose. New radiotherapy techniques in radiation therapy for left breast cancer help optimize dose to radiation volume and better protect healthy organs, which requires high accuracy when patient set - up. Errors due to equipment or patient set - up will lead to the risk of overdosage or underdosage and risk of relapse. Therefore, radiation therapy requires high precision throughout the process from simulation to planning and conducting radiation therapy. Radiation therapy for left breast cancer combined with Deep Inspiration Breath - hold (DIBH) and Optical Surface Management System (OSMS)causes the heart to move further away from the breast and chest wall during radiation therapy, helping to reduce the cardiac dose significantly, still ensuring the radiation dose to the target volume. The advantage of OSMS is that in addition to being applied for fastpatient set - up, without tattooing on the skin, it also provides real - time monitoring during the entire treatment process. When the patient’s breathing rate exceeds a certain threshold (0,3cm) the radiation beam is turned off to prevent toxicity. Therefore, understanding and understanding the benefits of patient set - up helps to achieve treatment goals, while reducing patient set - up time for more comfort, reducing pressure on the number of patients, especially for patients large radiotherapy center. Keyword: Radiation therapy for left breast cancer, Deep Inspiration Breath - hold, Optical Surface Management System, cardiovascular risk.

The relationship between cardiac dosimetry and tumour quadrant location in left sided whole breast and chest wall adjuvant radiotherapy

BACKGROUND: Radiotherapy after breast surgery decreases locoregional recurrence and improves survival. This is not without risks from radiation exposure and could have implications in clinical practice. Our study investigates the correlation between tumour location and radiation dose to the heart. METHODS: Left-sided breast cancer patients who had radiotherapy at Aberdeen Royal Infirmary in 2010 were identified. Tumour location was established from notes and imaging. Radiotherapy planning scans were reviewed, and cardiac doses calculated. The mean cardiac dose, maximum dose and volume of the heart in the field, along with V5-V40, were determined. RESULTS: 40 patients had mastectomies and 118 breast conserving surgery. The median percentage of the heart in the field and the Interquartile Range was 0.59% (0.03–1.74) for all patients, with the highest for lower inner quadrant (LIQ) tumours 1.20% (0.29–2.40), followed by mastectomy 0.94% (0.02-1.82). The mean heart dose showed a higher median for mastectomies 1.59 Gy (1.00-1.94), followed by LIQ tumours 1.58 Gy (1.31–2.28), with an overall median of 1.42 Gy (1.13–1.95). The median percentage of the heart in the field, the mean cardiac dose and V5-V30 did not reach statistical significance, however, V40 and the maximum dose did. CONCLUSIONS: The benefits of radiotherapy after breast cancer surgery are established, but with potential harm from cardiac exposure. Our cohort showed higher radiation exposure to the heart in patients with LIQ tumours and mastectomies but reached significance only for V40 and maximum dose. This highlights tumour location as a potentially important risk factor for cardiac exposure with breast radiotherapy.

Myocardial functional and structural abnormalities after adjuvant radiotherapy for breast cancer. Relation to cardiac radiation exposure

Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): The Funds Pierre Masure, Alphonse and Marie Walckiers & De Winter-Vermant, by King Baudouin Foundation Background Radiation therapy (RXT) is a keystone in breast cancer (BC) treatment which allows to reduce risk of local recurrence and cancer related mortality. Yet these benefits may be offset by increases in cardiovascular mortality due to late radiation induced cardiotoxicity. Indeed, prior works in patients exposed to high cardiac radiation dose demonstrated development of diffuse and focal myocardial fibrosis by cMR. However, whether such effects may also occur after contemporary BC-RXT with lower cardiac dose exposure, has not yet been evaluated. Purpose To evaluate the long-term cardiac safety of contemporary RXT for BC, we sought to estimate the prevalence of cardiac functional and structural focal and myocardial abnormalities in BC survivors treated by RXT 10 years earlier, in direct relation to measured local radiation dose exposure. Methods In a prospective cross-sectional study, we studied 27 women (mean age 62 ± 7 years) treated with adjuvant RXT but without chemotherapy for a first left (n= 12) or right sided (n= 15) BC between 2009 and 2011, which had no history of coronary artery or cardiac disease and compared them to 20 age matched (64 ± 10 years) healthy female controls (without history of BC or RXT). All subjects underwent 3T cMR to measure LV volumes, function, global longitudinal (GLS), circumferential (GRS) and radial strains (GRS) as well as extracellular volume (ECV) and late gadolinium enhancement (LGE). Functional and structural abnormalities in women with BC were compared to healthy controls. We also compared abnormalities among patients with left vs right BC and related them to mean heart radiation dose measured at the time of RXT (Figure). Results Mean cardiac radiation exposure in BC survivors was 1.87 ± 1.7 Gy (range 0-7.9 Gy). Exposure was significantly (p < 0.001) higher in left (3.3 ± 0.66 Gy) than in right (0.84 ± 0.65 Gy) sided BC. Indexed LV mass was slightly lower in BC patients than in controls (46 ± 6 vs 51 ± 9 g/m2, p = 0.03), whereas indexed end-diastolic (66 ± 11 vs 66 ± 12 ml/m2, p = NS) and end-systolic volumes (25 ± 8 vs 24 ± 7 ml/m2, p = NS) were similar. Also, LV ejection fraction (63 ± 6 vs 64 ± 6, p = NS), GLS (-14.7 ± 1.9 vs -15.5 ± 1.8, p = NS), GCS (-20.0 ± 3.6 vs -19.3 ± 5.9, p = NS) and GRS (40.9 ± 10.7 vs 37.0 ± 9.0, p = NS) were not statistically different in BC survivors than in controls. No patient presented LGE, and ECV was similar in BC patients exposed to RXT (28.3 ± 2.8) than in controls (29.3 ± 2.4, p = 0.58). Also, no differences in ECV between left and right sided BC and no statistical correlation between ECV and mean heart dose (r = 0.01, p = NS) was observed. Conclusions In this preliminary work, patients with BC treated by adjuvant RXT 10 years ago, presented no significant structural or functional abnormalities in relation to cardiac dose exposure nor in comparison to healthy controls. This suggests that current RXT protocols for BC are safe without long-term functional or morphological cardiac side effects.

Low cardiac dose and neutrophil-to-lymphocyte ratio predict overall survival in inoperable esophageal squamous cell cancer patients after chemoradiotherapy

We aimed to determine the prognostic significance of cardiac dose and hematological immunity parameters in esophageal cancer patients after concurrent chemoradiotherapy (CCRT). During 2010–2015, we identified 101 newly diagnosed esophageal squamous cell cancer patients who had completed definitive CCRT. Patients' clinical, dosimetric, and hematological data, including absolute neutrophil count, absolute lymphocyte count, and neutrophil-to-lymphocyte ratio (NLR), at baseline, during, and post-CCRT were analyzed. Cox proportional hazards were calculated to identify potential risk factors for overall survival (OS). Median OS was 13 months (95% confidence interval [CI]: 10.38–15.63). Univariate analysis revealed that male sex, poor performance status, advanced nodal stage, higher percentage of heart receiving 10 Gy (heart V10), and higher NLR (baseline and follow-up) were significantly associated with worse OS. In multivariate analysis, performance status (ECOG 0 & 1 vs. 2; hazard ratio [HR] 3.12, 95% CI 1.30–7.48), heart V10 (> 84% vs. ≤ 84%; HR 2.24, 95% CI 1.26–3.95), baseline NLR (> 3.56 vs. ≤ 3.56; HR 2.36, 95% CI 1.39–4.00), and follow-up NLR (> 7.4 vs. ≤ 7.4; HR 1.95, 95% CI 1.12–3.41) correlated with worse OS. Volume of low cardiac dose and NLR (baseline and follow-up) were associated with worse patient survival.

Cardiac Dose Control and Optimization Strategy for Left Breast Cancer Radiotherapy With Non-Uniform VMAT Technology

Purpose: A novel in-house technology “Non-Uniform VMAT (NU-VMAT)” was developed for automated cardiac dose reduction and treatment planning optimization in the left breast radiotherapy. Methods: The NU-VMAT model based on IGM (gantry MLC Movement coefficient index) was established to optimize the volumetric modulated arc therapy (VMAT) MLC movement and modulation intensity in certain gantry angles. The ESAPI embedded in Eclipse® was employed to connect TPS and the optimization program via I/O relevant DICOM RT files. The adjuvant whole-breast radiotherapy of 14 patients with left breast cancer was replanned using our NU-VMAT technology in comparison with VMAT and IMRT technology. Dosimetric parameters including D1%, D99%, and Dmean of PTV, V5, V10, and V20 of ipisilateral lung, V5, D20, D30, and Dmean of heart, monitor units (MUs), and delivery time derived from IMRT, VMAT, and NU-VMAT plans were evaluated for plan quality and delivery efficiency. The quality assurance (QA) was conducted using both point-dose and planar-dose measurements for all treatment plans. Results: The IGM−NU−VMAT curves with plan optimization (range from 50% to 147%) were converged more significantly than IGM-VMAT curves (range from 0% to 297%). The dose distribution requirements of the target and normal tissues could be met using IMRT, VMAT, or NU-VMAT; the lowest Dmean was achieved in NU-VMAT plans (5.38 ± 0.46 Gy vs 5.63 ± 0.61 Gy in IMRT and 7.95 ± 0.52 Gy in VMAT plans). Statistically significant differences were found in terms of delivery time and MU when comparing IMRT with VMAT and NU-VMAT plans ( P < .05). In comparison with IMRT plans, the MU and delivery time in NU-VMAT plans dramatically decreased by 69.8% and 28.4%, respectively. Moreover, NU-VMAT plans showed a high gamma passing rate (96.5% ± 1.11) in plane dose verification and minimal dose difference (2.4% ± 0.19) in point absolute dose verification. Conclusion: Our non-uniform VMAT facilitated the treatment strategy optimization for left breast cancer radiotherapy with dosimetric advantage in cardiac dose reduction and delivery efficiency in comparison with the conventional VMAT and IMRT.