ESTRO 2024 - Abstract Book

S253

Brachytherapy - Gynaecology

ESTRO 2024

Figure 2. Cumulative EQD2 doses to the OARs with and without free hand needles.

(FHN=free hand needle)

Conclusion:

Our study shows that using free hand needles with the standard cervical cancer applicator, you can increase the dose to the HR-CTV and decrease bladder and rectum doses. There was no significant change with GTVD98 dose, which is explained by GTV being at the high dose area and when free hand needles are usually helping to reach the edges of the HR-CTV. The largest advantage was shown with a specific group of cervical cancer patients with large tumours (appr. 70 cm3).

With OARs, using free hand needles resulted less dose deposited to all delineated organs except to the vaginal wall (recto-vaginal point). Statistically significant differences were found with bladder and rectum.

We recognize that free hand technique requires experience and skill from the physician and dose planner. Without such expertise this might lead to needles being not optimally positioned and at worst case can result in major vein or organ perforation. However, using blunt tipped needles may help avoiding perforations. Right applicator selection, such as ones with oblique needle paths or custom made applicators may also help with positioning needles to the target.

Keywords: cervix cancer, interstitial, free hand needles

References:

[1] Recommendations from Gynaecological (GYN) GEC-ESTRO Working Group (I): concepts and terms in 3D image based 3D treatment planning in cervix cancer brachytherapy with emphasis on MRI assessment of GTV and CTV, Christine Haie-Meder, Richard Pötter, Erik Van Limbergen, et al., Radiother Oncol. 2005 Mar 74(3):235-45