Computed tomography-planned interstitial brachytherapy for locally advanced gynecologic cancer: Outcomes and dosimetric predictors of urinary toxicity

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• 作者：Mark J. Amsbaugh¹ ; Neal Bhatt¹ ; Thomas Hunter¹ ; Jeremy Gaskins² ; Lynn Parker³ ; Daniel Metzinger³ ; Ashley Amsbaugh⁴ ; Keith Sowards¹ ; Moataz N. El-Ghamry¹ ; ^{Moataz.elghamry@louisville.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Gynecologic cancer ; Interstitial brachytherapy ; Dosimetric predictors of toxicity ; Cervical cancer ; Vaginal cancer ; Endometrial cancer ; Vulvar cancer ; Brachytherapy
• 刊名：Brachytherapy
• 出版年：2016
• 出版时间：January-February 2016
• 年：2016
• 卷：15
• 期：1
• 页码：49-56
• 全文大小：1099 K

文摘

To identify dosimetric predictors of outcome and toxicity in patients receiving CT-planned interstitial brachytherapy (ISBT) for gynecologic cancers.

d="absSec_2">Methods and Materials

d="abspara0015">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.

d="absSec_3">Results

d="abspara0020">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).

d="absSec_4">Conclusions

d="abspara0025">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.