Impact of MRI-based planning in transperineal interstitial brachytherapy for locally advanced cervix tumors: Clinical, dosimetric and toxicity outcomes.

Autors de IIS La Fe

• Luis Suso Martí

  Autor

• José Pérez Calatayud

  Autor

Autors aliens a IIS La Fe

• Guevara Barrera, Diana
• Rodriguez Villalba, Silvia
• Sanchis-Sanchez, Enrique
• Lago Martin, Jose Domingo
• Blazquez Molina, Francisco
• Santos Ortega, Manuel

Grups d'Investigació

• Investigación Clínica y Traslacional en Cáncer

  

  Leader

  José Gómez Codina

• Unidad Mixta de Investigación en Radiofísica e Instrumentación nuclear en medicina

  Leader

  Facundo Ballester Pallares

Abstract

PURPOSE: To compare dosimetric characteristics, clinical outcomes, and toxicity in patients with locally advanced cervical cancer(LACC) treated with transperineal interstitial brachytherapy(P-ISBT), using CT-based planning or MRI-based planning with a monoinstitutional MRI-compatible applicator, Template Benidorm(TB). MATERIALS AND METHODS: We retrospectively analyzed 106 women treated with P-ISBT for LACC from 2006 to 2022. P-ISBT was CT-based, with Martinez Universal Perineal Interstitial Template(MUPIT) between 2006 and 2012, or MRI-based planning (TB) since 2013. Volumetric, clinical, and dosimetric parameters were compared between applicators. RESULTS: Forty-six (43.4%) patients were treated with MUPIT, and 60 (56.6%) with TB. Median follow-up was 42 months (4-188). No significant difference was observed in 5-year local control (LC), regional control (RC), distant failure (DF), overall survival (OS), and disease-specific survival (DSS) between applicators. The TB cohort had fewer needles (p?=?0.001), halved median CTV volume (p < 0.001), increased median D90%CTV dose (p < 0.005), and lower D2cc values in rectum/bladder (p < 0.001). G3 chronic toxicity was 15% in the MUPIT group and 6% in TB (p?=?0.15), with no G4 toxicity reported. Rectal hemorrhage was lower in the TB group (p?=?0.002). Larger CTV volumes correlated with higher rectal D2cc and rectal hemorrhage (p?=?0.001; p?=?0.029, respectively), and enterovaginal fistula (p?=?0.03; p < 0.001, respectively). Median CTV volume was 152.82 cc (35.3-256.78) in patients with chronic rectal toxicity and 102.9 cc (21.4-329.41) in those without (p?=?0.001). CONCLUSION: MRI's superior CTV-volume definition results in smaller treatment volumes, lower D2cc for rectum and bladder, and a trend towards higher CTV D90%. Rectal hemorrhage was significantly lower in the MRI-based group. A significant correlation was observed between larger CTV-volumes, higher rectal D2cc and rectal hemorrhage/enterovaginal fistula.