Preliminary clinical outcomes of patients treated with vaginal brachytherapy alone using multi-channel vaginal brachytherapy applicator in operated early-stage endometrial cancer.

BACKGROUND: Recommendations for adjuvant treatment for postoperative, early-stage endometrial cancer varies from observation through vaginal brachytherapy alone to pelvic radiation. While observation alone can lead to recurrence, external radiotherapy has increased morbidity. The aim of this study is to show our results with vaginal brachytherapy alone using a multichannel applicator for treatment of early-stage endometrial cancer. MATERIALS AND METHODS: Consecutive patients undergoing vaginal brachytherapy alone following surgery for early-stage endometrial cancer were examined. A Miami multichannel vaginal brachytherapy applicator was used to deliver HDR brachytherapy in 62 patients from May 2013 to June 2018. CT scan-based images guided planning. A dose of 5.5-6.5 Gy × 4 fractions was prescribed 5 mm from the surface of the applicator. RESULTS: At a median follow up of 19 months (6-48 months), 93% of patients treated were alive with no recurrence. Two patients had only local recurrence, and 1 was salvaged with external radiotherapy and chemotherapy. There was only one nodal failure and 2 distant failures. There was no grade 2 or higher vaginal, gastrointestinal or genitourinary toxicity. CONCLUSION: Vaginal brachytherapy alone using a multichannel applicator can be considered for early-stage endometrial cancers without compromising outcomes.

Single Institution Experience of Postoperative Electron Beam Radiation Therapy in the Treatment of Keloids.

PURPOSE: Surgical excision followed by postoperative radiation therapy is an accepted modality to prevent keloid recurrence. Our practice has been to use electron beam radiation postoperatively to prevent recurrence, and we share our experience with this method in this study. METHODS AND MATERIALS: Twenty-two patients with 40 keloids treated postoperatively with electron beam radiation at our institution from 2014 to 2019 were analyzed retrospectively. Electron beam radiation was used for treatment in all cases, and radiation was initiated within 24 hours of surgery. A dose of 20 Gy in 5 fractions was delivered to the postoperative scar in 95% of the sites, and 8 Gy to 10 Gy in a single fraction was delivered to the remaining 5%. The patients were followed up, and recurrences were documented. RESULTS: At a mean follow-up of 35 months (range, 7-66 months), local control and cosmesis were achieved in 90% (36 of 40) of the treated sites with electron beam radiation therapy delivered at a dose of 20 Gy in 5 fractions. All recurrent keloids were located on the anterior chest wall over the sternum. There was no difference in outcome based on age, sex, or keloid length. CONCLUSIONS: Electron beam radiation therapy is a feasible, convenient, and safe modality for postoperative treatment of keloids. It achieves excellent local control with no grade 3 or higher toxicities.

Studies on Fundamental Interaction Parameters for Stainless Steel and Titanium Biomaterials Using Flattened and Un-Flattened Megavoltage X-Ray Beams.

Purpose: This work presents the measure of fundamental interaction parameters like mass attenuation coefficient (µ/ρ), mean energy, total atomic (σa) and electronic (σe) cross section, effective atomic number (Zeff), electron density (Nel) and mean free path (mfp) using FF and UF megavoltage x-ray beam for high Z implants. Methods: Narrow beam geometry is used to find out mass attenuation coefficient (µ/ρ) (MAC) which is then used to calculate mean energy (using NIST data), total atomic (σa) and electronic cross section (σe) for different energies. The effective atomic number (Zeff), Electron density (Nel), mean free path (mfp) for both flattened and unflattened x-ray beams for high Z material stainless steel (SS316) and titanium alloy (Grade 5) are studied. Results: The mean energies calculated from NIST data against mass attenuation coefficient were in good agreement with Monte Carlo value. It shows that spectral weighted effective atomic number is independent of megavoltage energies in the Compton region. Effective electron density calculated using Zeff and MAC method is lesser compared to direct method for both high Z materials. The mean free path (mfp) is higher along the central axis than off-axis for flattened beam in comparison to unflattened beam for both of the high Z materials studied because of the variation in energy spectrum for both FF and UF x-ray beams. Conclusion: This study elaborated the fundamental interaction parameters of different energies of flattened and unflattened x-ray beam interactions with high Z materials such as Stainless Steel (SS316) and Titanium (Grade5) relevant in a clinical scenario.