Purpose: An integrated magnetic resonance scanner and linear accelerator (MR-linac) was implemented with daily online adaptive radiation therapy (ART). This study evaluated patient-reported experiences with their overall hospital care as well as treatment in the MR-linac environment. Methods: Patients pre-screened for MR eligibility and claustrophobia were referred to simulation on a 1.5T MR-linac. Patient-reported experience measures were captured using two validated surveys. The 15-item MR-anxiety questionnaire (MR-AQ) was administered immediately after the first treatment to rate MR-related anxiety and relaxation. The 40-item satisfaction with cancer care questionnaire rating doctors, radiation therapists, the services and care organization and their outpatient experience was administered immediately after the last treatment using five-point Likert responses. Results were analyzed using descriptive statistics. Results: 205 patients were included in this analysis. Multiple sites were treated across the pelvis and abdomen with a median treatment time per fraction of 46 and 66 minutes respectively. Patients rated MR-related anxiety as “not at all” (87%), “somewhat” (11%), “moderately” (1%) and “very much so” (1%). Positive satisfaction responses ranged from 78-100% (median 93%) across all items. All radiation therapist-specific items were rated positively as 96-100%. The five lowest rated items (range 78-85%) were related to general provision of information, coordination, and communication. Overall hospital care was rated positively at 99%. Conclusion: In this large, single-institution prospective cohort, all patients had low MR-related anxiety and completed treatment as planned despite lengthy ART treatments with the MR-linac. Patients overall were highly satisfied with their cancer care involving ART using an MR-linac
Background: 10-25% of patients diagnosed with breast cancer have triple negative breast cancer (TNBC). TNBC is more aggressive than receptor-positive breast cancer. Objective: The objective of this study is to examine the demographics of this patient population. Methods: The Commission on Cancer tumor registry was queried for breast cancers from 2006 to 2013. The tumors were divided into groups according to receptor status. Patient demographics were then analyzed along with TNM staging defined by the American Joint Committee on Cancer. Results: Breast cancer tumors were identified (n=3267) and complete receptor data was available for 1238 tumors. Of these, 83% (1028/1238) of tumors were non-TNBC, while 17% (210/1238) were TNBC. Patients with TNBC were more likely be <40 years of age (p=0.018) and African American (p<0001). No significant difference was found comparing insurance type, median household income, or duration from diagnosis to definitive treatment between the TNBC and non-TNBC groups. Conclusion: TNBC is more common among African-American and younger women, but not more common among uninsured patients or those below the poverty level. This suggests an actual difference in tumor biology and not simply a health disparity
The purpose of this work is to quantify the dosimetric effect of two types of uncertainty in permanent prostate brachytherapy implants: failure to (1) image or (2) precisely localize all the seeds implanted. Both of these aspects are due to limitations of current imaging technology. An idealized pre-plan as well as clinical post-implant data for I-125 were used in this analysis. Monte Carlo simulations were done to evaluate the impact of missing seeds and of seed localization uncertainty on predicting the dose distributions. The indices chosen to compare dose distributions were the dose received by 90% of the target volume (D90), and the tumour control probability (TCP). Initial results show that for both types of uncertainties considered in this work, the mean values for TCP and D90 decreased as the magnitude of the uncertainty (number of seeds missing or magnitude of displacement) increased. For both sources of uncertainty, the effects were larger for the pre-plan (with a fixed lattice of seeds) than for the clinical cases (in which seeds were less orderly). Although the trends seen in mean values for TCP and D90 allow generalizations on the expected effect of seed localization uncertainties for a series of patients, the variability in those mean values demonstrate that for a single treatment in an individual patient it is very difficult to predict the values of TCP and D90 in the presence of the imaging uncertainties considered here.
We have evaluated the effect of the anisotropy of individual seeds on dose distributions for permanent prostate implants using and The dose distributions were calculated for various implants using both the line source and point source calculational formalisms, for two different models of and seeds. The dose distributions were compared using cumulative dose volume histograms (DVH) and cumulative difference dose volume histograms (ΔDVH) for the prostate target volume and for the rectum surface. The DVHs could not distinguish between the dose distributions from isotropic and non-isotropic seeds. However, the ΔDVHs were useful in determining the fraction of the target volume for which the difference between the dose distribution for line sources and for point sources exceeded a threshold value. The dose distributions were calculated (1) for all the seeds oriented co-linearly, along either the x-, y-, or z-axis, and (2) for the seeds at randomized orientations, more closely resembling the clinical situation. For all cases, there was a significant difference in the effect of seed anisotropy from the different seed types. For the geometrically simpler test cases with a small number of seeds, the effect of anisotropy on the dose distribution was too large to ignore for any of the seed types investigated. For the idealized pre-plan case, the effect was much smaller. For clinical prostate implants, the calculations done with seeds oriented co-linearly along the z-axis (needle implant axis) were a reasonable approximation for those from simulations of seeds with randomized orientations. Again, the effect of anisotropy varied drastically between different seed models, and also between different clinical cases. However, the effect of anisotropy must be considered in the context of all the other uncertainties in clinical brachytherapy treatments.
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