ESTRO 2024 - Abstract Book

S1070

Clinical - Gynaecology

ESTRO 2024

In total, 29/58 centres answered. Among them, 58.6% (17/29) perform ≥5 cases/year. Most of the centres are able to perform all techniques, although only 16/29 have access to BT. When in-field local relapse was given and surgery was contraindicated, 79.3% of the radiation oncologists (RTO) performed BT in endometrial cancer, but only 24% (7/29) treated with BT in cervical cancer in-field recurrence. In this clinical situation, 17.2% use SBRT for re retratment, 14% reirradiate with protontherapy (PT) and 31% of the centres indicated palliative doses, regardless of the technique. In radical intention/treatment, both in endometrial and cervical cancer reirradiation cases, 44.8% and 65.4%, respectively, prescribed doses up to the OaR tolerability. However, 38% and 19.2%, respectively, treated with doses >50Gy. For pelvic wall/parametrial in-field relapse, 46.4% of the centres reirradiated with SBRT, 32% with BT and 18% with EBRT. Among them, 60% of the centres prescribed a dose depending of the OAR tolerability. In lymph node reirradiation, SBRT was the technique of choice in most centres (90%), 38% of them precribing a dose >50Gy. As for protontherapy (PT) reirradiation, only one centre has experience, not only in local but also in infield pelvic recurrence. Regarding target volume in BT, all centres use Image-Guided Adaptive BT (IGABT) with magnetic ressonance image (MRI) to define a GTV and HR-CTV, with a margin of 5-10mm, depending on relapse extension. In EBRT and PT, the definitions of GTV, CTV and PTV are heterogeneous.

Conclusion:

Reirradiation is not well standardized in gynaecological cancer and remains a challenging treatment in the clinical practice. The results of this survey showed an increasing number of centres that offer reirradiation treatments, with SBRT being present not only in lymph node recurrences, but also in local and pelvic wall recurrences. Despite BT is the feasible alternative in local relapse, only 16/29 centres perform this technique, mainly in endometrial cancer reirradiation. In cervical cancer infield recurrence, RTOs remain conservative and around 30% of the centres indicate palliative treatment. Doses >50Gy seemed to be not usually achievable despite the technological advances and the interstitial BT. Moreover, the main objective in most retreatment doses is not to increase toxicity and sparing OaR. Nevertheless, the heterogeneity in clinical practice and the low evidence make it necessary to build some recommendations in this setting. Currently, the GINECOR working group is carrying out a systematic review and a Delphi recommendations on treatment and technique of reirradiation in gynaecological cancer.