Faculty Bibliography

Purpose: While Ir-192 remains the American mainstay isotope for gynecologic high dose rate (HDR) brachytherapy, Co-60 is an isotope that has been used abroad but has yet to impact the U.S. market. Co-60 has an advantage of a longer half-life than Ir-192 which may lead to long-term cost-savings; however, its higher energy requires greater shielding than does Ir-192. To assess clinicians' acceptability for this one-time shielding cost, a survey of U.S. radiation oncologists was conducted, and we previously reported their willingness-to-pay (WTP). The purpose of this study is to analyze what percentage of physicians would accept the onetime expense of additional shielding based on cost estimates from an internal shielding report and vendor price quotes for a single sample institution. Materials and Methods: A nationwide survey was undertaken to assess physician knowledge of Co-60 and their WTP a one-time expense for additional shielding, assuming a source more cost-effective than Ir-192 were available. With 440 respondents, 280 clinicians were decisionmakers who provided WTP answers, and the results were previously reported. Subsequently, we conducted shielding analysis of an HDR suite in a single sample institution to obtain the tenth-value layers (TVLs) necessary to maintain adequate shielding. Partnering with an external vendor of both lead and ultra-high density modular shielding, we calculated the costs necessary for design, shielding, shipping, and installation for both union and non-union settings, and compared these costs to decision makers' WTP. Results: For the single institution sample suite to appropriately shield for Co-60, 1.11 TVLs, 2.46 TVLs, and 1.15 TVLs would have to be added, respectively, to the walls, door, ceiling & floor to achieve the same current level of shielding. Cost estimates of adding shielding using proprietary ultra-high density modular shielding were $173.5K and $211K for non-union and union setting, respectively. Costs for lead shielding instead were $376.5K and $418K, respectively. The percentage of all 280 respondents who would accept these cost estimates for ultrahigh density modular shielding (union and non-union) or lead shielding (union and non-union) were 17.5%, 11.4%, 3.9%, and 3.2%, respectively. Of the 122 self-described decision-makers who were ABS members, the percentage of these who would accept these cost estimates for ultra-high density modular shielding (union and non-union) or lead shielding (union and non-union) were 18%, 9%, 2.4%, and 1.6%, respectively. of the 227 self-described decision-makers who were more than 5 years postresidency completion, the percentage of these who would accept these cost estimates for ultra-high density modular shielding (union and nonunion) or lead shielding (union and non-union) were 18.5%, 12.8%, 4.4%, and 3.5%, respectively. Conclusions: By comparing the cost of additional shielding for a sample institution's HDR suite with radiation oncologists' WTP, this multiinstitutional collaboration noted that less than 20% of clinicians would accept the most favorable financial situation of ultra-high density modular shielding with non-union labor. Percentage of cost-acceptability did not vary in subgroup analysis by ABS membership or years of experience. This analysis is limited by looking at the TVL requirements of only a single sample institution and cost estimates from a single vendor. However, knowing that the sole vendor of Co-60 afterloaders for gynecological cancer brachytherapy treatment has left the American market, we gain information by looking at the cost of shielding with reference to clinician WTP

PURPOSE/OBJECTIVE:To investigate cardiac toxicity associated with breast radiation therapy (RT) at 10-year follow-up in BCIRG-001, a phase 3 trial comparing adjuvant anthracycline chemotherapy (fluorouracil, doxorubicin, and cyclophosphamide) with anthracycline-taxane chemotherapy (docetaxel, doxorubicin, and cyclophosphamide) in women with lymph node-positive early breast cancer. METHODS AND MATERIALS/METHODS:Prospective data from all 746 patients in the control arm (fluorouracil, doxorubicin, and cyclophosphamide) of BCIRG-001 at 10-year follow-up were obtained from Project Data Sphere. Cardiac toxicities examined included myocardial infarction (MI), heart failure (HF), arrhythmias, and relative and absolute left ventricular ejection fraction decrease of >20% from baseline. Toxicities were compared between patients who received RT versus no RT, left-sided RT versus no RT, and internal mammary nodal RT versus no RT. RESULTS:Of the 746 patients, 559 (75%) received RT to a median dose of 50 Gy. Myocardial infarction occurred in 3 RT patients (0.5%) versus 6 no-RT patients (3%) (P=.01). Heart failure was seen in 15 RT patients (2.7%) versus 3 no-RT patients (1.6%) (P=.6). Among these, 35 RT patients (18%) had a left ventricular ejection fraction relative decrease of >20% baseline versus 7 (10%) who did not receive RT (P=.1). Arrhythmias were more common in RT patients (3.2%) versus no-RT patients (0%) (P=.01). On univariable and multivariable analysis HF was not significantly associated with RT, and MI was negatively associated with RT. CONCLUSIONS:In this retrospective analysis of prospective toxicity outcomes, there is an increased risk of arrhythmias but no clear evidence of significantly increased risk of MI or HF at 10 years in lymph node-positive women treated with breast RT and uniform adjuvant doxorubicin-based chemotherapy. Given the low incidence of these outcomes, studies with larger numbers are needed to confirm our findings.

Purpose/UNASSIGNED:Brain metastases are common in patients with limited-stage small cell lung cancer (LS-SCLC) due to the inability of most chemotherapeutics to penetrate the blood-brain barrier. Prophylactic cranial irradiation (PCI) is therefore recommended for use in patients with a good response to concurrent chemoradiotherapy. However, PCI is not always delivered; therefore, we investigated the reasons for PCI omission in patients who underwent therapy with curative intent. Methods and materials/UNASSIGNED:We retrospectively reviewed all patients with LS-SCLC who were treated with curative intent at our institution. Overall survival and cumulative incidence of brain metastasis were estimated by the Kaplan-Meier method. The Pearson χ2 test and Mann-Whitney U test were used to examine factors associated with PCI use, and prognostic factors were analyzed with Cox proportional hazards modeling. Results/UNASSIGNED:We examined 208 patients who were treated for LS-SCLC at our institution. A total of 115 patients (55%) received PCI. The most common documented reason for PCI omission was patient refusal due to neurotoxicity concerns (38%). Physician assessment of being medically unfit (33%) and of advanced age (8%) were the second and third most common reasons, respectively. Karnofsky performance status and clinical American Joint Committee on Cancer stage but not PCI were significantly associated with overall survival. Only clinical stage remained an independent factor on multivariate analysis. Conclusions/UNASSIGNED:Approximately half of patients with LS-SCLC ultimately receive PCI, generally for guideline-recommended reasons. The most common reason for PCI omission was patient concerns regarding neurotoxicity. Efforts to decrease PCI neurotoxicity, including hippocampal-sparing radiation and memantine use, may increase the use of this survival-improving intervention in eligible patients with LS-SCLC.

PURPOSE/OBJECTIVE:Ir-192 is the predominant source for high-dose-rate (HDR) brachytherapy in United States markets. Co-60, with longer half-life and fewer source exchanges, has piloted abroad with comparable clinical dosimetry but increased shielding requirements. We sought to identify practitioner knowledge of Co-60 and establish acceptable willingness-to-pay (WTP) thresholds for additional shielding requirements for use in future cost-benefit analysis. METHODS AND MATERIALS/METHODS:A nationwide survey of U.S. radiation oncologists was conducted from June to July 2015, assessing knowledge of HDR sources, brachytherapy unit shielding, and factors that may influence source-selection decision-making. Self-identified decision makers in radiotherapy equipment purchase and acquisition were asked their WTP on shielding should a more cost-effective source become available. RESULTS:Four hundred forty surveys were completed and included. Forty-four percent were ABS members. Twenty percent of respondents identified Co-60 as an HDR source. Respondents who identified Co-60 were significantly more likely to be ABS members, have attended a national brachytherapy conference, and be involved in brachytherapy selection. Sixty-six percent of self-identified decision makers stated that their facility would switch to a more cost-effective source than Ir-192, if available. Cost and experience were the most common reasons provided for not switching. The most common WTP value selected by respondents was <$25,000. CONCLUSIONS:A majority of respondents were unaware of Co-60 as a commercially available HDR source. This investigation was novel in directly assessing decision makers to establish WTP for shielding costs that source change to Co-60 may require. These results will be used to establish WTP threshold for future cost-benefit analysis.

BACKGROUND: Patients undergoing implant-based reconstruction in the setting of postmastectomy radiation therapy suffer from increased complications and inferior outcomes compared with those not irradiated, but advances in radiation delivery have allowed for more nuanced therapy. The authors investigated whether these advances impact patient outcomes in implant-based breast reconstruction. METHODS: Retrospective chart review identified all implant-based reconstructions performed at a single institution from November of 2010 to November of 2013. These data were cross-referenced with a registry of patients undergoing breast irradiation. Patient demographics, treatment characteristics, and outcomes were analyzed. RESULTS: Three hundred twenty-six patients (533 reconstructions) were not irradiated, whereas 83 patients (125 reconstructions) received radiation therapy; mean follow-up was 24.7 months versus 26.0 months (p = 0.49). Overall complication rates were higher in the irradiated group (35.2 percent versus 14.4 percent; p < 0.01). Increased maximum radiation doses to the skin were associated with complications (maximum dose to skin, p = 0.05; maximum dose to 1 cc of skin, p = 0.01). Different treatment modalities (e.g., three-dimensional conformal, intensity-modulated, field-in-field, and hybrid techniques) did not impact complication rates. Prone versus supine positioning significantly decreased the maximum skin dose (58.5 Gy versus 61.7 Gy; p = 0.05), although this did not translate to significantly decreased complication rates in analysis of prone versus supine positioning. CONCLUSIONS: As radiation techniques evolve, the maximum dose to skin should be given consideration similar to that for heart and lung dosing, to optimize reconstructive outcomes. Prone positioning significantly decreases the maximum skin dose and trends toward significance in reducing reconstructive complications. With continued study, this may become clinically important. Interdepartmental studies such as this one ensure quality of care. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.