Chest Wall Deformity in the Radiation Oncology Clinic

Abstract

Abstract. Background Adjuvant radiation therapy for women with breast cancer is associated with a reduction in local recurrence and, in many patients, a survival benefit (1, 2). As risk of cardiac events is correlated with the mean heart radiation dose (MHD), radiation oncological planning often focuses on techniques to reduce the MHD in women with left-sided breast cancer (3). Individual anatomic variation, including breast size, breast ptosis, tumor bed location, heart position and chest wall shape, all impact the ability of the radiation oncologist to achieve optimal MHD. In particular, pectus excavatum (PE) has been identified as a challenging situation for treatment planning in breast cancer.PE is a congenital deformity of the chest wall associated with sternal depression. It accounts for about 90% of anterior chest wall disorders and has an incidence of one in 400 to one in 1,000 births (4). PE is about four times more prevalent in males than females (5). Classically, PE has been measured on computed tomography (CT) by the Haller index (HI), which is used to determine which patients might benefit from surgical correction. PE is well recognized as a condition which may increase MHD during left-sided breast radiation, prompting the investigation of several radiotherapy techniques to address this clinical problem, including intensity-modulated radiation therapy (6), deep inspiration breath-hold technique (DIBH) (7), and lateral decubitus positioning (8).The purpose of this analysis was to determine the incidence of PE in women treated with radiation therapy for breast cancer at our Institution and to define anatomical chest wall metrics predictive of elevated MHD in patients undergoing breast radiotherapy. Patients and MethodsData source and study cohort. We retrospectively reviewed the records of 273 patients consecutively simulated for left-sided breast cancer or at our Institution between January 2013 and December 2014. The Yale Institutional Review Board approved this study (#150301553). Patients underwent 3-dimensionsal conformal planning, with either forward planned fixed gantry field-in-field technique or wedges as indicated by individual patient geometry. Cardiac segmentation included both cardiac muscle and the pericardium, starting at the branch point of the pulmonary arteries and continuing inferiorly to the cardiac apex. The MHD was recorded from the treatment planning system using heterogeneity corrections (Eclipse Version 13.6; Varian, Palo Alto, CA, USA). Contribution to MHD from supraclavicular, axillary, or boost fields was not considered in the measurement of MHD. Patients with PE who were treated with DIBH were also retrospectively re-planned on their free breathing (FB) CT scan for comparison.Variables. Patients were classified as having PE based on physical examination at the time of consult, which was confirmed upon review of axial imaging (Figure 1). Thoracic surgeons initially developed the HI to quantify the degree of the pectus deformity by 5295 This article is freely accessible onli...

Pectus excavatum and adjuvant radiotherapy for early stage breast cancer: balancing dose to target versus heart

“…increased ADC [8] consistent with our results. On the other hand, in non-responding metastases no ADC increase was observed consistent with a sharp increase in the AUC at fraction 3 ( Supplementary Figure 4).…”

“…In one study 3D-CRT was compared to more advanced RT techniques regarding dose to target and organs at risk (OARs) [7]. Another study evaluated 3D-CRT in ten patients with PE treated with whole breast irradiation (WBI) and compared MHDs to those in a group of breast cancer patients without PE [8].…”

Is pectus excavatum a risk factor for radiation‐induced lung disease in patients undergoing radiation therapy following breast‐conserving surgery?

“…Pectus excavatum is the most common congenital chest wall deformity, with an incidence of 1 in 300–1000 births . In one study, 3.7% of 273 patients who underwent RT to left breast tissue had clinically apparent PE . There is a concern that the administration of RT to breast tissue results in a greater radiation dose to the lungs in patients with PE than in those without this condition because of the concavity of the chest wall in the former, leading to a greater frequency of pulmonary complications.…”

“…27 In one study, 3.7% of 273 patients who underwent RT to left breast tissue had clinically apparent PE. 28 There is a concern that the administration of RT to breast tissue results in a greater radiation dose to the lungs in patients with PE than in those without this condition because of the concavity of the chest wall in the former, leading to a greater frequency of pulmonary complications. Several recent studies involving dosimetric analysis of DVHs of RT to breast tissue in patients with PE revealed that IMRT delivers a smaller ipsilateral lung dose than 3D-CRT.…”

Advantages of Post-Mastectomy Proton Beam Therapy in a Breast Cancer Patient With Pectus Excavatum

“…Reduction in cardiac dose is particularly important in high-risk patients such as this patient having coexistent chemotherapy-induced cardiomyopathy. Other methods of treatment have been proposed to solve this difficult clinical problem including volume-modulated arc therapy, intensitymodulated radiation, and deep inspiration breath-hold technique resulting in cardiac radiation reduction by anywhere from 30% to 70% [9]. But PE creates another complex scenario with the inward deformity of the chest wall causing compression of the heart, which increases not only the exposure of the heart to chest wall radiation but also exacerbates the underlying decreased cardiac output [10].…”