Partial Breast Irradiation for Patients With Early-Stage Invasive Breast Cancer or Ductal Carcinoma In Situ: An ASTRO Clinical Practice Guideline.

PURPOSE: This guideline provides evidence-based recommendations on appropriate indications and techniques for partial breast irradiation (PBI) for patients with early-stage invasive breast cancer and ductal carcinoma in situ. METHODS: ASTRO convened a task force to address 4 key questions focused on the appropriate indications and techniques for PBI as an alternative to whole breast irradiation (WBI) to result in similar rates of ipsilateral breast recurrence (IBR) and toxicity outcomes. Also addressed were aspects related to the technical delivery of PBI, including dose-fractionation regimens, target volumes, and treatment parameters for different PBI techniques. The guideline is based on a systematic review provided by the Agency for Healthcare Research and Quality. Recommendations were created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength. RESULTS: PBI delivered using 3-dimensional conformal radiation therapy, intensity modulated radiation therapy, multicatheter brachytherapy, and single-entry brachytherapy results in similar IBR as WBI with long-term follow-up. Some patient characteristics and tumor features were underrepresented in the randomized controlled trials, making it difficult to fully define IBR risks for patients with these features. Appropriate dose-fractionation regimens, target volume delineation, and treatment planning parameters for delivery of PBI are outlined. Intraoperative radiation therapy alone is associated with a higher IBR rate compared with WBI. A daily or every-other-day external beam PBI regimen is preferred over twice-daily regimens due to late toxicity concerns. CONCLUSIONS: Based on published data, the ASTRO task force has proposed recommendations to inform best clinical practices on the use of PBI.

Deep inspiration breath hold with electromagnetic confirmation of chest wall position for adjuvant therapy of left-sided breast cancer: Technique and accuracy.

PURPOSE: With most patients now living long after their breast cancer diagnosis, minimizing long-term side effects of breast cancer treatment, such as reducing late cardiac and pulmonary side effects of radiation therapy (RT), is particularly important. It is now possible to use an electromagnetic tracking system to allow real-time tracking of chest wall (CW) position during the delivery of RT. Here, we report our experience using electromagnetic surface transponders as an added measure of CW position during deep inspiration breath hold (DIBH). METHODS AND MATERIALS: We conducted a single-institution institutional review board-approved retrospective review of 15 female left-sided breast cancer patients treated between July 2012 and June 2013 with conventional whole breast radiation. We compared daily port films with treatment planning digitally reconstructed radiographs to establish daily setup accuracy, then used Calypso tracings to compare the position of the CW during the daily port film with the position of the CW during that day's treatment to determine the reproducibility of the breath hold position. Finally, we created competing treatment plans not using DIBH and used a paired t test to compare mean heart (MH) and left anterior descending (LAD) coronary artery dose between the 2 techniques. RESULTS: Mean total error (inter- and intrafraction) was dominated by interfraction error and was greatest in the longitudinal direction with a mean of 2.13 mm and 2 standard deviations of 8.2 mm. DIBH significantly reduced MH and LAD dose versus free breathing plans (MH, 1.26 Gy vs 2.84 Gy, P ≤ .001; LAD, 5.49 Gy vs 18.15 Gy, P ≤ .001). CONCLUSIONS: This study demonstrates that DIBH with electromagnetic confirmation of CW position is feasible, and allows potential improvement in the accurate delivery of adjuvant RT therapy for breast cancer.

Vascular and neural mechanisms of ACh-mediated vasodilation in the forearm cutaneous microcirculation.

The relative contribution of endothelial vasodilating factors to acetylcholine (ACh)-mediated vasodilation in the forearm cutaneous microcirculation is unclear. The aims of this study were to investigate the contributions of prostanoids and cutaneous C fibers to basal cutaneous blood flow (CuBF) and ACh-mediated vasodilation. ACh was iontophoresed into the forearm, and cutaneous perfusion was measured by laser-Doppler flowmetry. To inhibit the production of prostanoids, four doses of acetylsalicylic acid (ASA; 81, 648, 972, and 1,944 mg) were administered orally. Cutaneous nerve fibers were blocked with topical anesthesia. Cyclooxygenase inhibition did not change basal CuBF or endothelium-mediated vasodilation to ACh. In contrast, ASA (972 and 1,944 mg) significantly reduced the C-fiber-mediated axon reflex in a dose-dependent fashion. Blockade of C-fiber function significantly reduced axon reflex-mediated vasodilation but did not affect basal CuBF or endothelium-dependent vasodilation. The findings suggest that prostanoids do not contribute significantly to basal CuBF or endothelium-dependent vasodilation in the forearm microcirculation. In contrast, prostanoids are mediators of the ACh-provoked axon reflex.

First author research productivity of United States radiation oncology residents: 2002-2007.

PURPOSE: Participation in investigative research is a required element of radiation oncology residency in the United States. Our purpose was to quantify the first author research productivity of recent U.S. radiation oncology residents during their residency training. METHODS AND MATERIALS: We performed a computer-based search of PubMed and a manual review of the proceedings of the annual meetings of the American Society for Therapeutic Radiology and Oncology to identify all publications and presented abstracts with a radiation oncology resident as the first author between 2002 and 2007. RESULTS: Of 1,098 residents trained at 81 programs, 50% published > or =1 article (range, 0-9), and 53% presented > or =1 abstract (range, 0-3) at an American Society for Therapeutic Radiology and Oncology annual meeting. The national average was 1.01 articles published and 1.09 abstracts presented per resident during 4 years of training. Of 678 articles published, 82% represented original research and 18% were review articles. Residents contributed 15% of all abstracts at American Society for Therapeutic Radiology and Oncology annual meetings, and the resident contribution to orally presented abstracts increased from 12% to 21% during the study period. Individuals training at programs with >6 residents produced roughly twice as many articles and abstracts. Holman Research Pathway residents produced double the national average of articles and abstracts. CONCLUSION: Although variability exists among individuals and among training programs, U.S. radiation oncology residents routinely participate in investigative research suitable for publication or presentation at a scientific meeting. These data provide national research benchmarks that can assist current and future radiation oncology residents and training programs in their self-assessment and research planning.

Endothelial dysfunction precedes C-fiber abnormalities in primary (AL) amyloidosis.

Primary (AL; immunoglobulin light-chain associated) amyloidosis is characterized by the deposition of pathological proteins in the extracellular matrix of tissues and organs. Autonomic and sensory peripheral neuropathy is a common feature of this disorder. The pathogenesis of the neuropathy is poorly defined. The aims of this study were to investigate vascular and neural function in the cutaneous microcirculation of AL amyloidosis patients. Seven patients with AL amyloidosis and controls were studied. Acetylcholine and sodium nitroprusside were iontophoresed into the forearm skin. Endothelial, smooth muscle, and C-fiber-mediated cutaneous blood flow (CuBF) were recorded by laser Doppler flowmetry. Endothelial vasodilation in the forearm skin was attenuated in AL amyloidosis patients (p = 0.007). Maximum endothelium-mediated CuBF in the patient group was reduced (p = 0.047). No group differences could be detected in the C-fiber response or smooth muscle vasodilation (p value not significant). Maximum C-fiber and endothelium-independent CuBF did not differ between the two groups (p value not significant). Early in the disease, AL amyloidosis patients present with impaired endothelial function. At this stage, C-fiber and smooth muscle function are still preserved. These data suggest that endothelial abnormalities precede and may contribute to the pathogenesis of the neuropathy associated with AL amyloidosis.