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PURPOSE: Technological advances with commercial production of surface applicators allowed high-dose-rate (HDR) afterloading brachytherapy to overpass challenges associated with the delivery of superficial radiation when treating non-melanoma skin cancer (NMSC). We reviewed our single institutional experience using HDR to treat basal (BCC) and squamous cell (SCC) carcinomas. MATERIAL AND METHODS: A retrospective review of all patients treated with HDR and Leipzig-style applicators for NMSC at the Radiation Oncology Department, AC Camargo Cancer Center, from March 2013 to December 2018 was performed. RESULTS: Seventy-one patients with 101 lesions (BCCs, 69.3% or n = 70) and median age 80 (range, 51-102) years old were evaluated. The median follow-up was 42.8 (range, 12-82) months. The 3-year and 5-year actuarial local control (LC) rates were 97.9% and 87.2%, respectively. On univariate analysis, treatments with EQD2 less than 50 Gy (p < 0.001) and dose per fraction smaller than 3 Gy (p < 0.001) were found to be statistically significant predictive factors of a worse outcome. On multivariate analysis, SCC had a worse prognosis over BCC (p = 0.007, HR = 2.3, CI: 1.2-6.6). All patients developed some degree of acute side effects graded 1 to 2. Grade 3 acute side effects were observed in 9 (8.9%) patients. Moreover, severe late side effects (grade 3), hypopigmentation, and telangiectasia were observed in 4 (3.9%) patients. No grade 4 acute or late side effects were seen in this cohort. CONCLUSIONS: HDR offers a convenient treatment schedule for patients and is associated with excellent LC. The most effective regimen, in terms of dose and fractionation, to treat superficial NMSC with HDR remains uncertain, but a moderate minimum EQD2 dose of 50 Gy should be used.
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Introduction: An increasing number of prostate permanent seeds implant (LDR) procedures are being performed annually for localized prostate cancer (CaP). As local intraprostatic radiotherapy, LDR needs exact volume and dose calculations before and after the implant of the radioactive sources. Post-implant dosimetric analysis is mandatory and is generally evaluated by CT. As different physicians can differ in their volume definition of the prostate gland on the same post-implant CT images, the final dosimetric quality of the implant may also vary. Material and Methods: Our purpose is to identify the degree of agreement among three professionals skilled on prostate imaging and the dosimetric consequences of any disagreement in the sets of images from 36 consecutive patients submitted to LDR as monotherapy at Hospital A.C. Camargo (São Paulo, Brazil) from February 2005 to July 2006. Results: Median reconstructed prostate volumes ranged from 20.0 cc to 70.3 cc. Student´s t-test showed significant differences in the prostate volumes among the 3 observers (p <0.001, p <0.001 and p =0.010, respectively). The Pearson´s correlation coefficient was 0.912 for prostate volumes, 0.762 for D90, 0.932 for V100 and 0.935 for V150 when all reviewers were considered. The global test revealed significant differences in D90, V100 and V150 among the reviewers (p <0.0001). Conclusion: CT-based post-implant dosimetry allow the calculation of dose delivered to the prostate and surrounding and intra-prostatic normal tissues, but this method does not provide enough information to allow observers to reproducibly delineate the prostate volume without any discordance, which impacts in the final dosimetry.