The Crucial Role of Advanced Image-Guided Brachytherapy for Locally Advanced Cervical Cancer in the Era of Systemic Treatment Intensification.

Background/objectives: Recent advancements in the treatment of LACC have focused on improving outcomes through systemic treatment intensification. Therefore, this review aims to analyze the brachytherapy (BT) techniques employed in recent studies that are likely to change upcoming clinical guidelines, and to discuss the evolving role of IGABT in optimizing patient outcomes.

Methods: This review focuses on BT practices reported across main phase III trials-OUTBACK, INTERLACE, CALLA, and KEYNOTE A18-compared with the EMBRACE I study. Analyzed parameters include BT modality, dose prescription techniques, imaging guidance, and overall treatment time (OTT).

Results: In EMBRACE I, MRI-based IGABT was mandatory, with 43% of patients receiving an intracavitary/interstitial (IC/IS) applicator; cumulative EQD2 D90 HR-CTV was 90 Gy with a median OTT of 46 days. The OUTBACK trial relied predominantly on point A-based BT, with limited use of volume-based BT (28%). The INTERLACE trial reported mixed BT approaches: 70% point A-based, 30% volume-based, and 20% 2D BT. A median cervical dose of 79.4 Gy was reported. CALLA maintained strong protocol adherence, with 60% volume-based BT and a median tumor EQD2 dose of 83 Gy, although lower in the Japan cohort. In the KEYNOTE A 18 cohort, volume-based BT was performed in 88% of patients, with a median D90 HR-CTV dose of 87 Gy; IC/IS applicators were used in 23% of cases.

Conclusions: Across these major studies, the following consistent pattern emerges: the quality and technique of BT impact survival outcomes and toxicity profile in LACC. MRI-based IGABT-with the use of IC/IS applicators when needed-is essential.