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In breast cancer treatment, intensity-modulated radiation therapy (IMRT) can be utilized to deliver more homogeneous dose to target tissues to minimize the cosmetic impact. We have investigated the effect of the respiratory cycle and radiation beam-on timing on the dose distribution in free-breathing dynamic breast IMRT treatment. Six patients with early stage cancer of the left breast were included in this study. A helical computed tomography (CT) scan was acquired for treatment planning. A four-dimensional computed tomography (4D CT) scan was obtained right after the helical CT scan with little or no setup uncertainty to simulate patient respiratory motion. After optimizing based on the helical CT scan, the sliding-window dynamic multileaf collimator (DMLC) leaf sequence was segmented into multiple sections that corresponded to various respiratory phases per respiratory cycle and radiation beam-on timing. The segmented DMLC leaf sections were grouped according to respiratory phases and superimposed over the radiation fields of corresponding 4D CT image set. Dose calculation was then performed for each phase of the 4D CT scan. The total dose distribution was computed by accumulating the contribution of dose from each phase to every voxel in the region of interest. This was tracked by a deformable registration program throughout all of the respiratory phases of the 4D CT scan. A dose heterogeneity index, defined as the ratio between (D20-D80) and the prescription dose, was introduced to numerically illustrate the impact of respiratory motion on the dose distribution of treatment volume. A respiratory cycle range of 4–8 s and randomly distributed beam-on timing were assigned to simulate the patient respiratory motion during the free-breathing treatment. The results showed that the respiratory cycle period and radiation beam-on timing presented limited impact on the target dose coverage and slightly increased the target dose heterogeneity. This motion impact tended to increase the variation of target dose coverage and heterogeneity between treatment fractions with different radiation beam-on timing. The target dose coverage and heterogeneity were more susceptible to the radiation beam-on timing for patients with long respiratory cycle (longer than 6 s) and large breast motion amplitudes (larger than 0.7 cm). The same results could be found for respiratory cycle up to 8 s and respiratory motion amplitude up to 1 cm. The heart dose distribution did not change significantly regardless of respiratory cycle and radiation beam-on timing. [ABSTRACT FROM AUTHOR]

Purpose: Early-stage glottic larynx squamous cell carcinoma (GLC) is a relatively common disease with excellent oncologic control, but treatment is associated with acute dysphagia and long-term voice quality changes. This phase 1 study of hypofractionated radiation therapy for early-stage GLC increased the fraction size while reducing the number of fractions until 5-fraction stereotactic ablative radiation therapy (SABR) was delivered.Methods and Materials: Eligible patients had received a diagnosis of stage Tis to T2 GLC. Patients who had undergone prior curative-intent surgery were excluded. The equipotent dose levels were as follows: (1) level 0, 50 Gy in 15 fractions (n = 4); (2) level 1, 45 Gy in 10 fractions (n = 13); and (3) level 2, 42.5 Gy in 5 fractions (SABR level, n = 12). Grade 3 or 4 laryngeal edema, voice, dyspnea, stridor, or cough were the predefined dose-limiting toxicities.Results: Twenty-nine patients were enrolled from November 2013 to March 2017. The median and minimum follow-up times were 39.2 and 13 months, respectively. Two actively smoking patients, 1 treated in level 1 (grade 4 laryngeal edema, grade 3 dysphagia) and 1 treated in level 2 (grade 3 laryngeal necrosis, dysphagia), developed dose-limiting toxicities. The former patient soon developed a local recurrence, and the latter patient recovered. There were a total of 5 local recurrences: 2 in level 0 and 3 in level 1. The Voice Handicap Index results showed robust long-term voice quality with median values of 7 and 0 at 6 and 12 months, respectively.Conclusions: Given the tolerability, excellent voice outcomes, and preliminary efficacy data of 5-fraction glottic larynx SABR, this regimen warrants further study. [ABSTRACT FROM AUTHOR]

Purpose: To determine the pain response and prevention of vertebral compression fractures (VCFs) after single-fraction stereotactic ablative radiation therapy (SABR) in conjunction with immediate vertebroplasty for spine metastases.Methods and Materials: Patients with localized spine metastases free from VCF associated with loss of vertebral height with a pain score ≥4 using the visual analog scale were enrolled. Spine SABR was performed with 20 Gy delivered to the gross disease and 14 Gy to the contiguous bone marrow in a single fraction. Immediate, prophylactic vertebroplasty was performed within 1 month after spine SABR. The primary endpoint was pain response at 3 months compared to the historical control with external beam radiation therapy from Radiation Therapy Oncology Group study 9714. Secondary endpoints included pain response at 1 month, duration of pain response, vertebroplasty rate, VCF rate, local control, and overall survival.Results: Thirty-five patients were enrolled, of whom 29 were deemed eligible and underwent single-fraction spine SABR. Twenty-three of these patients subsequently underwent prophylactic vertebroplasty. The 3-month pain response was significantly improved compared to Radiation Therapy Oncology Group study 9714: 95% versus 51% (P < .0001). The local control with a median follow-up of 9.6 months was 92%. The freedom from VCF was 90% at 1 year. Spine SABR was well tolerated with no grade 2 or higher toxicities. A single patient with disease extending from the vertebral body into the spinal canal developed vertebroplasty-related myelopathy, which was corrected with surgery.Conclusions: Single-fraction SABR immediately followed by prophylactic vertebroplasty improves pain response compared with conventional radiation therapy while providing long-term pain control and structural stability of the treated spine. Vertebroplasty is well tolerated as a prophylactic measure in patients without loss of vertebral height after spine SABR. Pain response and VCF rates are similar to patients undergoing SABR alone. Thus, patients who would benefit most from the addition of vertebroplasty need to be further identified. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the tolerability of a dose-escalated 5-fraction stereotactic body radiation therapy for partial-breast irradiation (S-PBI) in treating early-stage breast cancer after partial mastectomy; the primary objective was to escalate dose utilizing a robotic stereotactic radiation system treating the lumpectomy cavity without exceeding the maximum tolerated dose.Methods and Materials: Eligible patients included those with ductal carcinoma in situ or invasive nonlobular epithelial histologies and stage 0, I, or II, with tumor size <3 cm. Patients and physicians completed baseline and subsequent cosmesis outcome questionnaires. Starting dose was 30 Gy in 5 fractions and was escalated by 2.5 Gy total for each cohort to 40 Gy.Results: In all, 75 patients were enrolled, with a median age of 62 years. Median follow-up for 5 cohorts was 49.9, 42.5, 25.7, 20.3, and 13.5 months, respectively. Only 3 grade 3 toxicities were experienced. There was 1 dose-limiting toxicity in the overall cohort. Ten patients experienced palpable fat necrosis (4 of which were symptomatic). Physicians scored cosmesis as excellent or good in 95.9%, 100%, 96.7%, and 100% at baseline and 6, 12, and 24 months after S-PBI, whereas patients scored the same periods as 86.5%, 97.1%, 95.1%, and 95.3%, respectively. The disagreement rates between MDs and patients during those periods were 9.4%, 2.9%, 1.6%, and 4.7%, respectively. There have been no recurrences or distant metastases.Conclusion: Dose was escalated to the target dose of 40 Gy in 5 fractions, with the occurrence of only 1 dose-limiting toxicity. Patients felt cosmetic results improved within the first year after surgery and stereotactic body radiation therapy. Our results show minimal toxicity with excellent cosmesis; however, further follow-up is warranted in future studies. This study is the first to show the safety, tolerability, feasibility, and cosmesis results of a 5-fraction dose-escalated S-PBI treatment for early-stage breast cancer in the adjuvant setting. [ABSTRACT FROM AUTHOR]