Faculty Bibliography

Radiation-associated cardiac disease, a heterogeneous and complex disease, manifests years or even decades following radiation exposure to the chest. It is associated with a significantly higher morbidity and mortality. Often, the presentation is vague and overlaps with many diseases, presenting unique diagnostic and management issues. As a result, a high index of suspicion followed by multimodality imaging is crucial, along with comprehensive screening to enable early detection. Timing of intervention should be carefully considered in these patients, because surgery is often complex with an emerging role of percutaneous interventions.

BACKGROUND:Radiation therapy (RT)-induced cardiotoxicity is among the concerning sequelae of breast cancer (BCA) treatment, particularly in HER2-positive BCA patients who receive anthracyclines and trastuzumab-based therapy. The aim of this study was to assess for early RT-induced changes in echocardiographic and circulating biomarkers of left ventricular (LV) function and evaluate their association with radiation dose to the heart among patients with HER2-positive BCA treated with contemporary RT. METHODS:A total of 47 women with HER2-positive BCA who were treated with an anthracycline, trastuzumab, and RT to the breast and/or chest wall ± regional lymph nodes were included in this study. Two-dimensional echocardiography with speckle-tracking imaging was performed at baseline (prechemotherapy), prior to and after RT (pre-RT and post-RT), and 6 months post-RT. High-sensitivity troponin I (hsTnI) was measured pre-RT and post-RT. Associations between mean heart dose (MHD) and changes in LV function after RT were examined in multivariable linear regression models. RESULTS:The MHD was 1.8 ± 1.5 Gy for patients receiving left-sided RT (n = 26) and 1.1 ± 1.3 Gy for patients receiving right-sided RT (n = 21). Pre-RT, post-RT, and 6-month post-RT echocardiograms were performed at median (interquartile range) of 49 days (27, 77) before and 54 days (25, 78) and 195 days (175, 226) after RT, respectively. Compared with pre-RT, a minimal decrease in LV ejection fraction was observed post-RT (61% ± 7% vs 59% ± 8%; P = .003) without any significant change in global longitudinal, circumferential, or radial strain or diastolic indices at the post-RT timepoint. Median (interquartile range) concentrations of hsTnI decreased from 5.7 pg/mL (3.0, 8.7) pre-RT to 3.7 pg/mL (2.0, 5.9) post-RT. There was no significant change in systolic or diastolic indices of LV function at 6 months post-RT compared with pre-RT. MHD was not associated with changes in echocardiographic parameters of LV function after RT. CONCLUSIONS:Breast RT using contemporary techniques can be delivered without evidence of early subclinical LV dysfunction or injury as measured by echocardiography and hsTnI in patients treated with anthracyclines and trastuzumab. Future studies should focus on identifying alternative biomarkers to elucidate early RT-induced cardiovascular effects and further characterizing long-term cardiovascular outcomes associated with contemporary breast RT.

INTRODUCTION:A broad range of stakeholders have called for randomised evidence on the potential clinical benefits and harms of proton therapy, a type of radiation therapy, for patients with breast cancer. Radiation therapy is an important component of curative treatment, reducing cancer recurrence and extending survival. Compared with photon therapy, the international treatment standard, proton therapy reduces incidental radiation to the heart. Our overall objective is to evaluate whether the differences between proton and photon therapy cardiac radiation dose distributions lead to meaningful reductions in cardiac morbidity and mortality after treatment for breast cancer. METHODS:We are conducting a large scale, multicentre pragmatic randomised clinical trial for patients with breast cancer who will be followed longitudinally for cardiovascular morbidity and mortality, health-related quality of life and cancer control outcomes. A total of 1278 patients with non-metastatic breast cancer will be randomly allocated to receive either photon or proton therapy. The primary outcomes are major cardiovascular events, defined as myocardial infarction, coronary revascularisation, cardiovascular death or hospitalisation for unstable angina, heart failure, valvular disease, arrhythmia or pericardial disease. Secondary endpoints are urgent or unanticipated outpatient or emergency room visits for heart failure, arrhythmia, valvular disease or pericardial disease. The Radiotherapy Comparative Effectiveness (RadComp) Clinical Events Centre will conduct centralised, blinded adjudication of primary outcome events. ETHICS AND DISSEMINATION:The RadComp trial has been approved by the institutional review boards of all participating sites. Recruitment began in February 2016. Current version of the protocol is A3, dated 08 November 2018. Dissemination plans include presentations at scientific conferences, scientific publications, stakeholder engagement efforts and presentation to the public via lay media outlets. TRIAL REGISTRATION NUMBER:NCT02603341.

PURPOSE/OBJECTIVE:Recurrent meningiomas remain therapeutically challenging, often progressive despite multimodality salvage. There are limited data guiding reirradiation (reRT), and proton beam radiation therapy (PBRT) offers a potential advantage owing to lower integral brain dose. PATIENTS AND METHODS/METHODS:We retrospectively conducted a review of 16 patients who received PBRT reRT for recurrent meningiomas. Kaplan-Meier and proportional hazards were used to determine post-PBRT progression-free survival (PFS) and overall survival (OS) and to evaluate clinical predictors. RESULTS: = .049). Overall late grade 3+ toxicity rate was 31%. Two patients (13%) developed radionecrosis at 6 and 16 months after PBRT; only 1 was symptomatic. CONCLUSIONS:This is the first series specifically analyzing PBRT alone as a reRT strategy for recurrent meningioma. We report fair intracranial control with low rates of radionecrosis at 1 year after reRT. However, strategies to achieve durable outcomes are needed, particularly for high-grade tumors.

BACKGROUND:Postmastectomy proton radiotherapy improves normal tissue sparing in comparison to photon-based approaches. Several studies have reported dosimetry comparison and tolerable acute toxicity profile with limited follow-up. We report our institutional experience of postmastectomy proton radiation including clinical efficacy and toxicities. METHODS:From December 2013 to February 2015, 42 consecutive patients who received mastectomy for non-metastatic breast cancer were treated with adjuvant chest wall and regional nodal proton therapy at a single proton center. 3D conformal uniform scanning with en face matching fields was used. RESULTS:The median follow-up among patients was 35 months (range 1-55 months). There was one local failure, zero regional nodal failure, and six distant failures. The 3-year rate of locoregional disease-free survival was 96.3%, metastasis-free survival was 84.1%, and overall survival was 97.2%. The only local failure event occurred on the chest wall within the radiation field, approximately 2.5 years after the completion of radiation. Skin dermatitis, fatigue, and esophagitis were the most common acute toxicity. All patients developed grade 1 or 2 acute skin toxicity and there was no grade 3 or 4 acute skin toxicity. Proton radiation is able to achieve excellent target coverage with median PTV V95 over 95% and heart sparing with median mean heart dose less than 1 Gy (RBE). CONCLUSION:With close to three years of median follow-up, post-mastectomy proton radiation has shown excellent locoregional control rates and favorable toxicity profile. Long-term adverse effect of heart-sparing radiation will require longer follow-up time and randomized clinical trials.

PURPOSE:The primary goal was to map the anatomic pattern of isolated nodal recurrences (NR) in the supraclavicular (SCV), axillary, and internal mammary nodes (IMNs) in patients with breast cancer treated with curative-intent surgery with or without radiation therapy (RT). Secondary objectives were to assess clinical and pathologic factors associated with patterns of NR and survival rates. METHODS AND MATERIALS:Patients with NR after treatment at a single cancer center during 1998 to 2013 were identified. Patients with prior distant metastases or NR without correlative imaging were excluded. All NRs were overlaid onto representative axial computed tomographic images. Multivariable analysis was performed to identify clinical and pathologic characteristics associated with NR. Kaplan-Meier curves were generated to assess the rate of relapse by nodal region according to pathologic feature or radiation treatment status. RESULTS:The locations of 243 NRs among 153 eligible patients were mapped. The majority of NR occurred in the axilla (42%; 102/243), followed by the IMN (32.5%; 79/243) and the SCV (25.5%; 62/243). Radiation Therapy Oncology Group (RTOG) or European Society for Radiation therapy and Oncology (ESTRO) clinical target volume encompassed 82% (198/243) of NRs. The majority of out-of-field NRs were located in the lateral and posterior SCV region for both RTOG (67%; 30/45) and ESTRO (89%; 49/55) guidelines. The high-risk patients who received regional RT to the SCV relapsed at a similar rate in the medial, but a higher rate in lateral SCV (P = .009), compared with low-risk patients who received no nodal RT. Lymphovascular invasion most strongly associated with IMN NR (P = .001); grade 3 disease highly associated with both IMN (P = .001) and SCV NR (P = .02). The presence of an IMN NR portended for significantly inferior overall survival (OS), compared with an axillary NR, with a 5-year OS of 59% versus 72%, respectively (P = .03). CONCLUSIONS:In this 3-dimensional image-based analysis of NR patterns in breast cancer patients treated with contemporary therapies, the lateral and posterior SCV represented a distinct site of NR that is not routinely included within current breast cancer contouring atlases. Grade 3 breast cancer and LVI were most commonly associated with the development of NR in the SCV. Modifying the CTV to encompass the lateral and posterior SCV in patients with breast cancer with these features might be justified.

PURPOSE:Most studies examining accelerated partial breast irradiation (APBI) have used twice-daily fractionation. Cosmesis with this approach has produced mixed results, and the optimal fractionation scheme remains unknown. We sought to evaluate the safety and efficacy of APBI with a total dose of 40 Gy in 10 daily fractions. METHODS AND MATERIALS:Between 2010 and 2014, we prospectively enrolled 106 patients to receive APBI after lumpectomy for invasive or in situ node-negative breast cancer. Radiation was administered via 3-dimensional conformal techniques. RESULTS:to <45% may improve tolerability. Overall, 3 breast cancer recurrences arose: 1 local recurrence in the original quadrant (3 years after APBI), 1 in a different ipsilateral quadrant (5 years after APBI), and 1 with distant disease 2 years after APBI. CONCLUSIONS:should be carefully constrained to limit local morbidity. Longer follow-up will be needed to establish efficacy and subsequent local recurrence rates.