Browsing by Author "Cox, John A."

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    Cost analysis of adjuvant management strategies in early stage (stage I) testicular seminoma
    (Dove Medical Press, 2015) Cox, John A.; Gajjar, Shefali R.; Lanni, Thomas B.; Swanson, Todd A.; Department of Radiation Oncology, IU School of Medicine
    BACKGROUND: Acceptable post-orchiectomy adjuvant therapy strategies for stage I seminoma patients include surveillance, para-aortic radiation therapy (RT), dog-leg RT, and a single cycle of carboplatin. The required follow-up recommendations were amended by the National Comprehensive Cancer Network (NCCN) in 2012. Given a cause-specific survival of nearly 100%, a closer analysis of the reimbursement for each treatment strategy is warranted. METHODS: NCCN guidelines were used to design treatment plans for each acceptable adjuvant treatment strategy. Follow-up charges were generated for 10 years based on 2012 (version 1.2012; unchanged in current version 1.2013) and 2011 NCCN (version 2.2011) surveillance recommendations. The 2012 Medicare reimbursement rates were used to calculate each treatment strategy and incremental cost-effectiveness ratios to compare the treatment options. RESULTS: Under the current NCCN follow-up recommendations, the total reimbursements generated over 10 years of surveillance, para-aortic RT, dog-leg RT, and carboplatin were $10,643, $11,678, $9,662, and $10,405, respectively. This is compared with the reimbursements as per the 2011 NCCN recommendations: $20,986, $11,517, $9,394, and $20,365 respectively. Factoring the rates of relapse into a salvage model, observation was found to be more costly and less effective ($-1,831, $-7,318, $-7,010) in the adjuvant management of stage I seminoma patients. CONCLUSION: Based on incremental cost-effectiveness ratios, para-aortic RT, dog-leg RT, and carboplatin are cost-effective options for the treatment of stage I seminoma when compared with observation; however, surveillance could potentially spare as many as 80%-85% of men diagnosed with stage I seminoma from additional therapy after radical inguinal orchiectomy. Such cost and reimbursement analyses are becoming increasingly relevant, but are not meant to usurp sound clinical judgment. Further studies are required to validate these findings.
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    Dosimetric Comparison of Treatment Techniques: Brachytherapy, Intensity- Modulated Radiation Therapy, and Proton Beam in Partial Breast Irradiation
    (2015) Hansen, Tara M.; Bartlett, Gregory K.; Mannina, Edward M. Jr.; Srivastava, Shiv P.; Cox, John A.; Das, Indra J.; Department of Radiation Oncology, IU School of Medicine
    Purpose: To perform a dosimetric comparison of 3 accelerated partial breast irradiation techniques: catheter-based brachytherapy (BT), intensity-modulated radiation therapy (IMRT), and proton beam therapy (PBT). Patients and Methods: Twelve patients with left-sided breast cancer treated with SAVI (Strut-Adjusted Volume Implant) were selected in this study. The original BT plans were compared with optimum plans using IMRT and PBT for 34 Gy (RBE) with 1.1 RBE in 10 fractions using identical parameters for target and organs at risk. Results: Significant reduction in maximum dose to the ipsilateral breast was observed with PBT and IMRT (mean 108.58% [PBT] versus 107.78% [IMRT] versus 2194.43% [BT], P = .001 for both PBT and IMRT compared to BT). The mean dose to the heart was 0%, 1.38%, and 3.85%, for PBT, IMRT, and BT, respectively (P < .001 and P = .026). The chest wall mean dose was 10.07%, 14.65%, and 29.44% for PBT, IMRT, and BT, respectively (P = .001 and .013 compared to BT). The PBT was superior in reducing the mean ipsilateral lung dose (mean 0.04% versus 2.13% versus 5.4%, P = .025 and P < .001). There was no statistically significant difference in the maximum dose to the ipsilateral lung, chest wall, 3-mm skin rind or in the mean ipsilateral breast V50% among the 3 techniques (P = .168, .405, .067, and .780, respectively). PBT exhibited the greatest mean dose homogeneity index of 4.75 compared to 7.18 for IMRT (P = .001) and 195.82 for BT (P < .001). All techniques resulted in similar dose conformality (P = .143). Conclusion: This study confirms the dosimetric feasibility of PBT and IMRT to lower dose to organs at risk while still maintaining high target dose conformality. Though the results of this comparison are promising, continued clinical research is needed to better define the role of PBT and IMRT in the accelerated partial breast irradiation treatment of early-stage breast cancer.
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    Improved human observer performance in digital reconstructed radiograph verification in head and neck cancer radiotherapy.
    (Springer, 2015-10) Sturgeon, Jared D.; Cox, John A.; Mayo, Lauren L.; Gunn, G. Brandon; Zhang, Lifei; Balter, Peter A.; Dong, Lei; Awan, Musaddiq; Kocak-Uzel, Esengul; Mohamed, Abdallah Sherif Radwan; Rosenthal, David I.; Fuller, Clifton David; Department of Radiation Oncology, IU School of Medicine
    Purpose: Digitally reconstructed radiographs (DRRs) are routinely used as an a priori reference for setup correction in radiotherapy. The spatial resolution of DRRs may be improved to reduce setup error in fractionated radiotherapy treatment protocols. The influence of finer CT slice thickness reconstruction (STR) and resultant increased resolution DRRs on physician setup accuracy was prospectively evaluated. Methods: Four head and neck patient CT-simulation images were acquired and used to create DRR cohorts by varying STRs at 0.5, 1, 2, 2.5, and 3 mm. DRRs were displaced relative to a fixed isocenter using 0–5 mm random shifts in the three cardinal axes. Physician observers reviewed DRRs of varying STRs and displacements and then aligned reference and test DRRs replicating daily KV imaging workflow. A total of 1,064 images were reviewed by four blinded physicians. Observer errors were analyzed using nonparametric statistics (Friedman’s test) to determine whether STR cohorts had detectably different displacement profiles. Post hoc bootstrap resampling was applied to evaluate potential generalizability. Results: The observer-based trial revealed a statistically significant difference between cohort means for observer displacement vector error (p = 0.02) and for Z-axis (p < 0.01). Bootstrap analysis suggests a 15% gain in isocenter translational setup error with reduction of STR from 3 mm to ≤2 mm, though interobserver variance was a larger feature than STR-associated measurement variance. Conclusions: Higher resolution DRRs generated using finer CT scan STR resulted in improved observer performance at shift detection and could decrease operator-dependent geometric error. Ideally, CT STRs ≤2 mm should be utilized for DRR generation in the head and break neck.