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

16 Cervix cancer

Li Tee Tan, Kari Tanderup, Jacob Lindegaard, Monica Serban, Remi Nout, Richard Pötter

1. Summary 2. Introduction 3. Anatomy 4. Pathology 5. Work up 6. Indications

3 3 4 5 5 6 7

9. Treatment planning

12 17 20 21 25 31 32

10. Dose, dose rate and fractionation

11. Monitoring

12. Results

13. Adverse Events 14. Key messages 15. References

7. Tumour, target volumes and organs at risk

8. Technique

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1. SUMMARY

Definitive radiotherapy, comprising external beam radiotherapy (EBRT) with concomitant cisplatin-based chemotherapy followed by brachytherapy (BT), is the treatment of choice for all patients with advanced cervical cancer (FIGO2018 IB3 – IVA). MRI-based image-guided adaptive BT (IGABT) is the new gold standard for cervical cancer BT. The technique allows for individualisation of treatment with dose and volume adaptation, and dose escalation or de-escalation where appropriate, to take into account tumour size and topography at diagnosis and at the time of BT while simultaneously sparing adjacent organs-at-risk (OAR). The entire treatment is predicated on the development of new concepts for target and OAR contouring and dose prescription and reporting, and new adapted applicators with greater flexibility for source placement including combined intracavitary-interstitial capability. A large clinical study of MRI-based IGABT in cervical cancer (EMBRACE-I) has shown unprecedented local and pelvic control rates of 92% and 87%, respectively, across all stages without increasing late morbidity.

2. INTRODUCTION

Standard of care definitive radiotherapy for cervical cancer comprises external beam radiotherapy (EBRT) with concomitant cisplatin-based chemotherapy followed by brachytherapy (BT). For many decades, technological developments in cervix cancer BT have been limited and treatment planning has been based on X-rays and approaches originally developed by the classical BT schools in the early/mid-20th century. The most commonly used system up to now is the Manchester point A system which involves standard doses prescribed to a fixed point regardless of tumour size, topography, and response to EBRT, and doses to organs at risk (OAR). This has resulted in a double penalty of suboptimal local control and survival, particularly for patients with large tumours, and significant treatment-related morbidity, particularly affecting the bowel, bladder, and vagina, with a major impact on health-related quality of life in survivors. With the advent of afterloading equipment in the 1980s, it became possible to modify individual source positions and dwell times to shape the dose distribution to the tumour topography while avoiding adjacent OAR. This has given rise to the development of new applicators with greater flexibility for source placement which would allow better adaptation of dose distributions to create complex shapes. The full potential of these new applicators is critically dependent on the use of 3D imaging, particularly magnetic

Cervical cancer has a low incidence in Western Europe and North America but remains one of the most common malignancies in women worldwide. The human papilloma virus (HPV) plays an important role in the genesis of cervical cancer and is present in >90% of cases. The HPV types most frequently implicated are types 16 and 18 found in ~70% of cases, with types 31 and 45 occurring in a further 10%. While systematic vaccination programmes against the most common high risk HPV types (16 and 18) have been initiated in several countries, they are not available in the vast majority of developing countries where cervical cancer is most prevalent. The survival rate for cervical cancer is 60-70% in Western Europe and North America, compared to only 40-50% in Central/Eastern Europe, and even lower in low- and middle-income (LMIC) countries. The lower survival rate in less affluent countries is largely due to more advanced disease at presentation because of the lack of systematic screening programmes. The availability of HPV self-testing is a potentially game-changing advance for early detection of cervical cancer [1].