ABSTRACT
PURPOSE: To investigate the use of topotherapy for accelerated partial breast irradiation through field-design optimization and dosimetric comparison to linear accelerator-based three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiation therapy (IMRT). METHODS AND MATERIALS: Hypothetical 3-cm lumpectomy sites were contoured in each quadrant of a left breast by using dosimetric guidelines from the National Surgical Adjuvant Breast and Bowel Project B-39/Radiation Therapy Oncology Group 0413 protocol. Coplanar intensity-modulated topotherapy treatment plans were optimized by using two-, three-, four-, five-, and seven-field arrangements for delivery by the tomotherapy unit with fixed gantry angles. Optimized noncoplanar five-field 3D-CRT and IMRT were compared with corresponding topotherapy plans. RESULTS: On average, 99.5% +/- 0.5% of the target received 100% of the prescribed dose for all topotherapy plans. Average equivalent uniform doses ranged from 1.20-2.06, 0.79-1.76, and 0.10-0.29 Gy for heart, ipsilateral lung, and contralateral lung, respectively. Average volume of normal breast exceeding 90% of the prescription and average area of skin exceeding 35 Gy were lowest for five-field plans. Average uniformity indexes for five-field plans using 3D-CRT, IMRT, and topotherapy were 1.047, 1.050, and 1.040, respectively. Dose-volume histograms and calculated equivalent uniform doses of all three techniques illustrate clinically equivalent doses to ipsilateral breast, lung, and heart. CONCLUSIONS: This dosimetric evaluation for a single patient shows that coplanar partial breast topotherapy provides good target coverage with exceptionally low dose to organs at risk. Use of more than five fields provided no additional dosimetric advantage. A comparison of five-field topotherapy to 3D-CRT and IMRT for accelerated partial breast irradiation illustrates equivalent target conformality and uniformity.
Subject(s)
Breast Neoplasms/radiotherapy , Radiotherapy, Conformal/methods , Tomography, Spiral Computed/methods , Breast Neoplasms/diagnostic imaging , Breast Neoplasms/pathology , Computer Simulation , Humans , Mastectomy, Segmental , Radiotherapy Dosage , Radiotherapy, Intensity-Modulated/methodsABSTRACT
PURPOSE: Leverage the National Cancer Database (NCDB) to evaluate trends in management of nonmetastatic squamous cell cancer (SCC) of the rectum and their effect on survival for this uncommon tumor. METHODS AND MATERIALS: Retrospective data was obtained from the NCDB for patients diagnosed with SCC of the rectum between 2004 and 2014, including cT1-4, cN0-2, cM0 tumors (cohort A, n = 2296). A subgroup analysis was performed on locally advanced tumors (cT1-T2, N+ or cT3, N any, subcohort B, n = 883), treated with chemoradiation (n = 706) or trimodality therapy (n = 177) including chemotherapy, radiation, and surgery. Pathological complete response rate following neoadjuvant therapy was obtained. Univariate and multivariate logistic regression analyses were performed to generate hazard ratios (HR) investigating factors associated with overall survival. Kaplan-Meier (K-M) method was used to estimate overall surviving proportion at 5 and 10 years. RESULTS: The K-M estimated 5 and 10 year overall survival for stage I disease was 71.3% and 57.8%, respectively; stage II disease was 57.0% and 38.9%, respectively; stage III disease was 57.8% and 41.5%, respectively. On multivariate analysis, higher cT category (P < 0.001) resulted in worse survival. For locally advanced tumors (subcohort B), there was no significant difference in survival between chemoradiation alone compared to trimodality therapy (P = 0.909 on multivariate analysis). CONCLUSIONS: Most providers manage locally advanced SCC of the rectum similar to anal cancer, which results in equivalent overall survival and spares patients from the additional morbidity associated with surgical resection.
Subject(s)
Carcinoma, Squamous Cell/therapy , Rectal Neoplasms/therapy , Adult , Aged , Aged, 80 and over , Carcinoma, Squamous Cell/pathology , Databases, Factual , Female , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Neoplasm Staging , Practice Patterns, Physicians' , Rectal Neoplasms/pathology , Young AdultABSTRACT
OBJECTIVE: To create a validated tool to measure digital rectal examination proficiency and aid with teaching of the examination. DESIGN: The Digital Rectal Examination Clinical Tool was created using a modified Delphi method with 5 urologists and 5 radiation oncologists. The instrument was then validated in a population of preclinical medical students examining male urological teaching associates, and clinical trainees (third- and fourth-year medical students and urology resident physicians) examining prospectively enrolled subjects. Trainees completed paired examinations with an attending urologist, and responses were scored with reference to the attending responses. SETTING: The instrument was validated at the University of Virginia in the urology clinic, endoscopic operating room, and main operating room settings. PARTICIPANTS: We tested the instrument on consenting subjects consisting of male urologic teaching associates (n = 12), clinic patients (n = 4), and operating room patients (n = 64). The participants were undergraduate (n = 302) and graduate (n = 9) medical trainees. RESULTS: In preclerkship trainees, improved scores in subjects without abnormal compared to those with abnormal findings demonstrated validity. In clinical trainees, scores on the Digital Rectal Examination Clinical Tool increased by 2% for each additional year of training, demonstrating construct validity. CONCLUSIONS: We used an expert panel to create a novel instrument for measuring digital rectal examination proficiency and validated it with preclinical and clinical trainee cohorts at our institution.