Summary of Research and Clinical Advancements

ESTRO 2026 Congress report

The management of gynaecological malignancies continues to evolve, driven by the investigation of novel therapeutic combinations, advanced radiotherapy techniques, and optimised treatment schedules. During ESTRO 2026, several key sessions presented important findings aimed at improving survival outcomes and preserving quality of life in patients with cervical and ovarian cancers. The presentations highlighted the expanding role of stereotactic ablative radiotherapy (SABR) in recurrent and oligometastatic settings, the potential of re-irradiation strategies, and the balance between treatment intensification and side effects. This report summarises the main findings and clinical implications from five major studies presented at the congress, providing an overview of current developments in gynaecological radiation oncology.

The randomised, multicentre, phase III CC3 trial (NCT04678791), presented by Professor Junjie Wang from Peking University Third Hospital, China, evaluated the efficacy and safety of nimotuzumab, a humanised epidermal growth factor receptor (EGFR) monoclonal antibody, in combination with concurrent chemoradiotherapy (CCRT) for patients with locally advanced cervical squamous cell carcinoma (LACC). A total of 286 patients were randomised 1:1 to receive either nimotuzumab plus CCRT (142 patients) or CCRT alone (144 patients). The 3-year progression-free survival (PFS) rate was significantly higher in the nimotuzumab group as compared with the control arm (87.2% vs. 77.4%, P=0.031), corresponding to a hazard ratio of 0.53. The objective response rate (ORR) was also significantly improved in the experimental arm (90.14% vs. 81.25%, P=0.032), with complete responses observed in 71.83% and 65.97% of patients, respectively. The most common grade 1–2 adverse events were anaemia and leukopenia, supporting a favourable tolerability profile. These findings suggest that the addition of nimotuzumab to CCRT may improve response rates and prolong PFS in this patient population. Study limitations include the exclusively Chinese patient population, the relatively lower doses delivered to the HR-CTV, and the longer overall treatment time (OTT). Therefore, further validation and investigation are warranted before broader generalisation of these results.

Professor Won-Lee Hee from Yonsei University College of Medicine, Korea, presented updates from the ongoing phase III SABR-ROC trial (KGOG 3064/KROG 2204; NCT05444270), which is evaluating whether the addition of SABR to standard salvage therapy improves 3-year overall survival in patients with recurrent ovarian cancer. At the time of presentation, 175 of the planned 180 patients had been enrolled, although 24 premature protocol discontinuations were reported. These occurred predominantly in the standard therapy arm, mainly due to withdrawal of consent by patients dissatisfied with not being assigned to stereotactic treatment following randomisation. In the SABR arm, 16 serious adverse events (SAEs) were reported, five of which were grade 3 or higher and considered radiotherapy-related, with bowel events being the most frequent. Final results have not yet been presented, as the study only completed accrual in February 2026 and includes a planned 3-year follow-up. However, as the first phase III trial in this clinical setting, it deserves close attention in the coming years. A parallel pattern-of-care survey showed that 91.7% of radiation oncologists considered radiotherapy effective in this setting, compared with 68.8% of gynaecologic oncologists. These findings highlight the need for greater interdisciplinary alignment regarding the role of SABR in recurrent ovarian cancer.

The international, multicentre RetroCOSMOS study (NCT06150222), presented by Professor Supriya Chopra from Tata Memorial Hospital, Mumbai, evaluated retreatment strategies and post-progression survival (PPS) in patients with synchronous or metachronous oligometastatic or oligo-recurrent cervical cancer treated between 2007 and 2021 across 26 international centres. Among 421 patients with complete follow-up. The results focussed on utilisation of systemic therapies and high precision radiation in patients with oligometastasis and oligorecurrent cervical cancer. The results demonstrated very encouraging outcomes with post-progression survival (PPS) exceeding 36 months. The results established the validity of 3 subclasses in oligometastatic and oligorecurrent cervical cancer as proposed at study inception (Class A: Synchronous Oligometastasis, median PPS=71 months, Class B: Metachronous Oligometastasis median PPS= 48.4 months), and Class C: Oligorecurrent; median PPS=49.5 months). Within RetroCOSMOS registry patients undergoing gynaecological reirradiation were also registered with very encouraging 3 year PPS of 42 months. As the registry includes patients treated before 2021 therefore only a small proportion received Bevacuzimab or immunotherapy.

 These data suggest that repeated local and systemic treatment strategies may contribute to prolonged survival beyond first progression in selected patients.

The randomised, multi-institutional phase II HEROICC trial (NCT04583254), presented by Professor Luca Mendez from Verspeeten Family Cancer Centre, Canada, assessed the feasibility and tolerability of hypofractionated radiotherapy (HypoRT) compared with conventional fractionation in cervical cancer, to optimise radiotherapy resource utilisation through shorter treatment schedules. The study did not reach its planned accrual target of 48 patients, enrolling only 17 participants, with a median follow-up of 2.9 years. Patients assigned to the HypoRT arm (40 Gy in 15 fractions) experienced greater deterioration in bowel function and bowel bother domains compared with those receiving conventional treatment (45 Gy in 25 fractions). Grade 3 or higher gastrointestinal adverse events were more frequent in the hypofractionated arm, including two cases of grade 3 diarrhoea and one case of grade 4 colonic stenosis, although this difference did not reach statistical significance (p=0.082). The results from this small subset of patients indicate the importance of balancing dose fractionation and monitoring of adverse events for ongoing and future initiatives investigating hypofractionation including highly conformal adaptive techniques for gynaecological cancers.

Professor Gabriella Macchia from the Responsible Research Hospital, Italy, presented a subgroup analysis of patients with oligometastatic ovarian cancer from the large prospective MITORT3/RAD study, aimed at evaluating the safety of SABR delivered within 12 months of bevacizumab completion. The analysis included 41 patients with 68 metastatic lesions, primarily located in the abdominal, pelvic, and thoracic regions. Fifteen acute adverse events were reported in eight patients, all below grade 3, mainly consisting of upper gastrointestinal symptoms, pain, and asthenia. Only one late adverse event was observed, consisting of grade 2 intestinal sub-occlusion. With a median actuarial follow-up of 28 months, the 1- and 2-year local control rates were 82.2% and 73.3%, respectively. These findings suggest that SABR administered within one year of bevacizumab exposure appears feasible and well-tolerated in this clinical setting.

In summary, the studies presented at ESTRO 2026 reflect the increasing complexity and personalisation of treatment strategies in gynaecological oncology. The CC3 trial and RetroCOSMOS findings support the potential value of treatment intensification and repeated local approaches in selected cervical cancer patients, while the HEROICC trial highlights the importance of using conformal treatment and carefully balancing dose fractionation in trials investigating hypofractionation. The SABR-ROC and MITORT3/RAD data further support the growing interest in SABR for recurrent and oligometastatic ovarian cancer, while also emphasising the importance of multidisciplinary consensus in treatment adoption. Collectively, these studies contribute to refining the role of radiotherapy across different gynaecological malignancy settings.

Bianca Santo 
Radiotherapy Unit, “Vito Fazzi” Hospital, Lecce, Italy
 

Donato Pezzulla
Radiation Oncology Unit, Responsible Research Hospital, Campobasso, Molise, Italy