Ria Mulherkar, David Grimm, Paniti Sukumvanich, Madeleine Courtney-Brooks, Michelle Boisen, Jessica Berger, Sarah Taylor, Jamie Lesnock, Shannon Rush, Allison Garrett, Haider Mahdi, John Comerci, Alexander Olaiwaye, Robert Edwards, Elangovan Doraisamy, Michael Hajduk, Christopher J Houser, Hayeon Kim, John Austin Vargo
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引用次数: 0
Abstract
Introduction: Several factors of template-based interstitial brachytherapy in gynecologic cancers, including large tumor size, invasion into adjacent organs or fistula, dose heterogeneity, and twice daily fractionation cause inherent dose-escalation effects, potentially increasing toxicity. This study reports a single-institutional dose escalation experience in twice daily template-based interstitial brachytherapy treatments to demonstrate tumor control and toxicity outcomes, with the hypothesis that with image-based planning dose-escalation with interstitial brachytherapy is safe and efficacious.
Methods: Patients treated with template-based interstitial brachytherapy at our institution from 2006 to 2022 were identified. Over time, HDR brachytherapy boost dose at our institution has been dose-escalated from 18.75 Gy in 5 fractions to 27.5 Gy in 5 fractions. Local control and survival outcomes were analyzed using the Kaplan-Meier method and log-rank test to compare between groups. Formal tumor control probability (TCP) analysis was performed using logistic dose-response modeling.
Results: 214 patients were identified with median follow-up of 28.1 months (IQR 8.2-58.7). Total HDR dose correlated significantly with local and locoregional control when analyzed as a continuous variable, and when dichotomized around median dose of 25 Gy (p = 0.024). TCP analysis showed a dose-response effect between HR CTV D90 and local control in the entire cohort, and separately in cervical and vaginal cancer subsets. The actuarial 5-year incidence of grade 3 or worse toxicity was 6.1%, and there was no significant association between toxicity and total HDR dose or HR CTV D90.
Conclusion: In patient treated with twice-daily template-based interstitial brachytherapy for gynecologic cancers brachytherapy dose correlates with local control with no significant association between brachytherapy dose and toxicity, thus suggesting room for dose-escalation.
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