Mark J Amsbaugh1, Neal Bhatt1, Thomas Hunter1, Jeremy Gaskins2, Lynn Parker3, Daniel Metzinger3, Ashley Amsbaugh4, Keith Sowards1, Moataz N El-Ghamry5. 1. Department of Radiation Oncology, University of Louisville, Louisville, KY. 2. Department of Bioinformatics and Biostatistics, University of Louisville, Louisville, KY. 3. Department of Obstetrics Gynecology and Women's Health, University of Louisville, Louisville, KY. 4. Department of Anesthesia and Perioperative Medicine, University of Louisville, Louisville, KY. 5. Department of Radiation Oncology, University of Louisville, Louisville, KY. Electronic address: Moataz.elghamry@louisville.edu.
Abstract
PURPOSE: To identify dosimetric predictors of outcome and toxicity in patients receiving CT-planned interstitial brachytherapy (ISBT) for gynecologic cancers. METHODS AND MATERIALS: Patients who received ISBT between 2009 and 2014 were reviewed. Demographic, disease specific, treatment, and toxicity data were collected. Logistic regression was used to model toxicity. A least absolute shrinkage and selection operator penalty was used to identify relevant predictors. Receiver operating characteristic curves were used to analyze the relation between dosimetric factors and urinary toxicity. RESULTS: Seventy-three patients received ISBT (21 at time of cancer recurrence and 52 at the first presentation). Thirty-six patients had cervical cancer, 16 had vaginal cancer, 13 had uterine cancer, and 8 had vulvar cancer. ISBT was performed using both high-dose-rate and low-dose-rate 192Ir sources (27 low dose rate and 46 high dose rate). With a median followup of 12 months, Grade 3 vaginal, urinary, and rectal toxicity occurred in 17.8%, 15.1%, and 6.8% of patients, respectively. No patients experienced Grade 4 or 5 toxicity. Dose to 0.1cc of urethra predicted for development of Grade 3 urinary toxicity (area under the curve of 0.81; 95% confidence interval: 0.66, 0.96). A 10% probability of a Grade 3 urinary toxicity associated with a dose of 23.1 equivalent dose in 2 Gy fractions (95% confidence interval: 9.51, 36.27 equivalent dose in 2 Gy fractions). CONCLUSIONS: ISBT is a safe treatment for gynecologic malignancies. The dose to 0.1cc significantly predicts for severe urinary toxicity. Our data suggests that dose to a small urethral volume may be the most significant predictor of urinary toxicity in patients receiving ISBT for gynecologic cancer.
PURPOSE: To identify dosimetric predictors of outcome and toxicity in patients receiving CT-planned interstitial brachytherapy (ISBT) for gynecologic cancers. METHODS AND MATERIALS: Patients who received ISBT between 2009 and 2014 were reviewed. Demographic, disease specific, treatment, and toxicity data were collected. Logistic regression was used to model toxicity. A least absolute shrinkage and selection operator penalty was used to identify relevant predictors. Receiver operating characteristic curves were used to analyze the relation between dosimetric factors and urinary toxicity. RESULTS: Seventy-three patients received ISBT (21 at time of cancer recurrence and 52 at the first presentation). Thirty-six patients had cervical cancer, 16 had vaginal cancer, 13 had uterine cancer, and 8 had vulvar cancer. ISBT was performed using both high-dose-rate and low-dose-rate 192Ir sources (27 low dose rate and 46 high dose rate). With a median followup of 12 months, Grade 3 vaginal, urinary, and rectal toxicity occurred in 17.8%, 15.1%, and 6.8% of patients, respectively. No patients experienced Grade 4 or 5 toxicity. Dose to 0.1cc of urethra predicted for development of Grade 3 urinary toxicity (area under the curve of 0.81; 95% confidence interval: 0.66, 0.96). A 10% probability of a Grade 3 urinary toxicity associated with a dose of 23.1 equivalent dose in 2 Gy fractions (95% confidence interval: 9.51, 36.27 equivalent dose in 2 Gy fractions). CONCLUSIONS:ISBT is a safe treatment for gynecologic malignancies. The dose to 0.1cc significantly predicts for severe urinary toxicity. Our data suggests that dose to a small urethral volume may be the most significant predictor of urinary toxicity in patients receiving ISBT for gynecologic cancer.
Authors: Sophia C Kamran; Matthias M Manuel; Paul Catalano; Linda Cho; Antonio L Damato; Larissa J Lee; Ehud J Schmidt; Akila N Viswanathan Journal: Brachytherapy Date: 2017-08-17 Impact factor: 2.362
Authors: Emily Flower; Salman Zanjani; Gemma Busuttil; Emma Sullivan; Wayne Smith; Kathy Tran; David Thwaites; Jennifer Chard; Viet Do Journal: J Contemp Brachytherapy Date: 2021-12-30