16. Cervix cancer - The GEC-ESTRO Handbook of Brachytherapy

Cervix cancer

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THE GEC ESTRO HANDBOOK OF BRACHYTHERAPY | Part II Clinical Practice Version 1 - 01/09/2023

Figure 5. (A) Example of diagram for recording findings of clinical examination (at diagnosis and at brachytherapy) (From www.embracestudy.dk) On the direct en face view, the shaded area represents the vaginal fornix.

a. Line separating upper third from middle third of vagina b. Line separating middle third from lower third of vagina

(B) Revised diagram for recording findings of clinical examination for CT-based contouring (From [13]) These clinical diagrams were revised to include measurement scales in all directions to facilitate recording of tumour target dimensions in a reliable and reproducible way. As parametrial disease is difficult to visualise on CT, a new parameter - “Near Maximum Distance” (NMD) - has been introduced for more precise width assessment on clinical examination.

for optimal local control and cure and attempts to replace BT with high tech EBRT techniques (e.g. IMRT or stereotactic radiotherapy) have resulted in inferior outcomes [7]. The use of image guidance has facilitated the use of BT in all stages of disease, including Stage IVA even with bladder and/or rectal fistula. Similarly, BT has an increasingly important role to maximise local control of selected patients with metastatic disease (good performance status, low volume metastases, good response to systemic chemotherapy).

7. TUMOUR, TARGET VOLUMES AND ORGANS AT RISK

In 2000, the GEC-ESTRO GYN Working Group was established to support and shape the emerging field of gynaecological IGABT. Clinicians from a few pioneering European IGABT centres (Leuven, Paris, Vienna) with different historical traditions met to discuss and agree a common language for prescribing, recording and reporting IGABT for cervix cancer. This culminated in the publication of two recommendations on contouring and dose/volume reporting in 2005 and 2006 [8, 9]. In 2005, the GEC-ESTRO GYN Working Group founded a network to promote collaboration between the increasing number of institutions with research and development activities in IGABT. The group launched the “IntErnational study on MRI-based BRachytherapy in locally Advanced CErvical cancer” (EMBRACE-I, www.embracestudy.dk) to evaluate the outcome of IGABT in a multi-centre setting in 2008. In 2010 and 2012, the GEC-ESTRO GYN network published a further two recommendations on applicator reconstruction and imaging [10, 11]. The Gyn GEC-ESTRO Recommendations I-IV have been used as the conceptual framework for the implementation of IGABT worldwide and are embedded into the new ICRU Report 89

Figure 6. General tumour and adaptive target concepts – schematic diagram General adaptive target concept with a CTV-T init based on the GTV-T init , and an individualised CTV-T adapt (CTV-T HR) based on the GTV-T init response after treatment and assessment of GTV T res . (From ICRU 89)

“Prescribing, Recording, and Reporting Brachytherapy for Cancer of the Cervix” [12]. In 2021, the GEC-ESTRO/ICRU concepts were adapted for CT-based contouring [13].

7.1 Tumour and target volumes The ICRU89/GEC-ESTRO recommendations are based on repetitive tumour assessment through clinical examination and cross-sectional imaging, with adaptation of dose according to the tumour extent at diagnosis, and the response to EBRT at the time of BT (Figure 6). A common terminology for different target volumes with different risks of recurrence at different time points has been defined.