ESTRO 2024 - Abstract Book

S318

Brachytherapy - Head & neck, skin, eye

ESTRO 2024

Purpose/Objective:

Since the last update of the GEC-ESTRO recommendations for head-and-neck (HN) brachytherapy in 2017 [1], advances in the understanding and management of HN cancers have influenced brachytherapy. We conducted a scoping review to map the evolution of HN brachytherapy practice and identify emerging topics since the previous guideline.

Material/Methods:

A systematic literature search was performed on Pubmed, EBSCOHost, EuropePMC, and Google Scholar for articles on HN brachytherapy from 2017 onwards; the search was last run June 29, 2023. We included primary studies on HN brachytherapy in English. This was complemented by bibliography scanning of secondary studies. Study details were extracted using a standardized template; qualitative (frequency counts) and qualitative (themes) analyses were done.

Results:

Systematic search yielded 213 unique articles, including one guideline [2] and four systematic reviews [3-6]. A total of 145 primary studies were included – 112 reported on clinical outcomes (majority were retrospective cohorts, 72); 17 were purely simulation/dosimetric studies. China consistently produced the most research output per year. The most studied sites were the oral cavity (n=75), oropharynx (n=41), and salivary glands (n=20). While high dose rate (HDR) brachytherapy was most reported on (n=58), there was resurgence of studies on low-dose rate (LDR) brachytherapy (n=52), in the form of permanent seed implants. In the latter, CT- (n=50) and template guidance (n=28) were described. While brachytherapy in the definitive setting was most discussed, 18 reported on peri-operative brachytherapy. Several reported on the use of 3D printing for template and applicator design (n=11) and new approaches to dose calculation or dose optimization algorithms (n=2). Table 1 summarizes emerging topics in relation to areas addressed in the 2017 GEC-ESTRO recommendations.

GEC-ESTRO

Recommendations

Topic

Emerging Interests (2017-2023)

(2017 Update)

Increasing LDR permanent seed implant may provide evidence for recommendations on dosimetry and treatment planning Emerging data on the utilization of interstitial seed brachytherapy for parotid cancers Increasing literature on the use of peri-operative brachytherapy, with one study reporting on longer follow up (10-year recurrence and survival rates) literature on

Schedules for HDR and pulsed-dose rate (PDR) brachytherapy (transitioning from LDR wires)

Fractionation schedules

Discussed primary brachytherapy in lip, oral cavity, oropharynx, nasopharynx, and superficial cancers

Brachytherapy use in specific subsites

Predominantly post operatively, with intraoperative and preoperative brachytherapy considered investigational delivered

Adjuvant Brachytherapy