ESTRO 2025 Congress report
By the reirradiation focus group (report #5/5)

1. Evolving practice: how reirradiation is shaping the role of the RTT
   RTT Symposium
   Presenter: Aileen Duffton

Advances in radiotherapy planning and delivery technologies have significantly expanded the possibilities for complex treatments, including reirradiation. These intricate treatments increase the need for skilled interdisciplinary collaboration across the entire treatment pathway. Reirradiation in particular poses particular challenges: increased risks from cumulative dose exposure, a scarcity of prospective studies, and inconsistent reporting of technical details in published literature.

ESTRO has launched several initiatives to address these gaps, including the establishment of a dedicated reirradiation focus group, a special journal issue on reirradiation, collaborative efforts to improve service delivery, and the development of guidelines that are intended to optimise all stages of the patient care pathway.

Radiation therapists (RTTs) play a pivotal role in the multidisciplinary team and are in direct contact with patients. Their role is evolving, as reirradiation presents opportunities for advanced practice. RTT-led roles have been established in areas such as image-guided radiotherapy (IGRT) and adaptive radiotherapy, highlighting the potential for task shifting. Advanced practice by RTTs not only enhances care delivery but also contributes to the profession’s development through skill innovation.

However, to implement advanced practice safely and effectively, there is a growing need for standardisation. This includes clear educational frameworks, defined levels of practice, and structured career progression. Advanced practice should extend beyond task delegation to involve unique RTT competencies and leadership in innovation.

The aim of this study was to optimise the IGRT protocol for reirradiation by gathering expert RTT feedback. A working group of 11 RTTs, each with over six years of IGRT experience, participated in two 90-minute workshops. Discussions covered acquisition, online image registration, and decision-making processes.

From these sessions, eight core themes, 19 challenges, and 35 key statements were identified. The themes were categorised into two domains, shown below.

• Professional practice and collaboration

1. Communication challenges and multidisciplinary involvement
2. Radiographer role and development
3. Clinical information and intent
4. Standards and guidelines

• Technical and clinical implementation:

5. Individualised approaches
6. Technical planning considerations
7. Imaging and verification techniques
8. Anatomical site-specific considerations

A manuscript is in preparation regarding these findings.

In conclusion, while a standardised framework for reirradiation practices is achievable, it must remain patient-centred and individualised. Interdisciplinary communication is critical, and advanced RTT practice is a key vehicle to improve patient care, expand RTT education opportunities, and promote professional growth.

Aileen Duffton

2. 𝘉𝘳𝘢𝘤𝘩𝘺𝘵𝘩𝘦𝘳𝘢𝘱𝘺 𝘧𝘰𝘳 𝘤𝘢𝘯𝘤𝘦𝘳 𝘳𝘦𝘪𝘳𝘳𝘢𝘥𝘪𝘢𝘵𝘪𝘰𝘯: t𝘩𝘦 𝘣𝘦𝘴𝘵 𝘵𝘰𝘰𝘭 𝘪𝘯 𝘵𝘩𝘦 𝘴𝘩𝘦𝘥?
   𝘙𝘛𝘛 𝘋𝘦𝘣𝘢𝘵𝘦
   𝗖𝗵𝗮𝗶𝗿𝘀: Primoz Petric (Switzerland), Mateusz Bilski (Poland)

➤ Speakers: Cyrus Chargari (France), Nicole Eder-Nesvacil (Austria), Umesh Mahantshetty (India), Alfonso Gomez-Iturriaga (Spain), Cristina Gutiérrez Miguélez (Spain), Luca Tagliaferri (Italy)

The debate provided discussion of detailed rationale, techniques, clinical outcomes, challenges, and future directions across various cancer sites, and supported brachytherapy's role in this challenging setting.

Physics and radiobiology rationale: Nicole Eder-Nesvacil discussed the physics aspects of the use of brachytherapy for reirradiation and explained why it was considered an excellent tool for this task due to its potential delivery of high target doses with steep dose gradients that spare surrounding normal tissues. She highlighted advantages of its use, such as flexibility, precise focal boosting, the use of hydrogel spacers, superior motion control due to planning for the clinical target volume without the need for a PTV, and the potential to use various fixation methods. Dosimetric uncertainties and the underlying dose distribution from previous external beam radiotherapy (EBRT) were discussed as crucial considerations for reirradiation.

Cyrus Chargari provided the radiobiology perspective. He emphasised the importance of the integral dose and how brachytherapy minimised it by delivering high doses to limited volumes. He noted the challenge of predicting complications and how brachytherapy could counteract hypoxia in fibrotic environments. Both these speakers concluded that brachytherapy offered the best dose distribution and target motion control for reirradiation and that dose prescription could be combined with previous treatments. They also called for advanced tools for rapid dose accumulation and uncertainty assessment in treatment planning systems. A critical point raised was the danger of considering the recovery factor in previously irradiated tissue and the importance of patient information and previous treatment cycles.

Application in gynaecological cancers Dr Umesh Mahant Shetty discussed the role of brachytherapy in the reirradiation of recurrent gynaecological cancers. He noted that local recurrences were often in-field (5-15%) and that salvage surgeries, while effective, showed significant rates of late morbidity. Brachytherapy offered symptom relief and improved quality of life because it delivered high doses locally. Advances in image-guided adaptive brachytherapy (IGABT) for cervical cancer (Retro-EMBRACE, EMBRACE, EMBRACE II) have shown remarkable outcomes in primary settings, and these findings could be used to inform reirradiation uses. Patient selection was identified as the most important prognostic factor. It involved restaging with PET-CT, state-of-the-art multiparametric MRI, tissue diagnosis, and evaluation of late sequelae from previous radiation. A multidisciplinary tumour board was stated to be essential. Various reirradiation approaches (brachytherapy alone, EBRT+brachytherapy, stereotactic body radiotherapy (SBRT), proton therapy, chemo and intraoperative radiotherapy (IORT) ) were mentioned, but the talk was focused on brachytherapy. Examples from Dr Umesh’s centre demonstrated the combination of EBRT (in the form of VMAT) with concomitant chemotherapy and brachytherapy for vaginal recurrence after prior radiotherapy and surgery, and the use of EBRT+brachytherapy for recurrent endometrial cancer. Experience at the Tata Memorial Centre in Mumbai, India, with 76 patients showed decent rates of local control, PFS and OS rates (60-70% after two years) with modest toxicity.

A review of 45 publications highlighted the challenges of relying on studies that involve small sample sizes and non-standardised protocols. Longer intervals between treatments improve outcomes, though the number of late toxicities may be slightly higher. Experience with advanced brachytherapy applications and imaging is crucial. Guidelines from ESTRO, the European Society of Gynaecological Oncology and the European Society of Pathology recommend IGABT as an alternative to radical surgery when high morbidity is a concern, and this suggests the need for referral to specialist centres. Challenges include defining cumulative dose-volume parameters and harmonising doses; a recent paper addressed these issues. Modalities should be offered based on radiation classification.

Application in prostate cancer Dr. Alfonso Gomez discussed salvage brachytherapy for radiorecurrent prostate cancer. Patient selection criteria included biochemical factors (prostate-specific antigen levels of < 10-20, DT > six months, failure interval > two years, life expectancy > five years), tumour characteristics (Gleason, extension, single lesion, oligorecurrence), functional status, and comorbidities. Evidence for salvage treatment with brachytherapy or SBRT is limited, mainly from small single-centre studies. Key studies were reviewed, including a prospective phase II trial that had shown 10-year biochemical failure and distant failures. A meta-analysis (MASTER) compared the results of the use of radiotherapy-based strategies (brachytherapy, SBRT) with those for non-radiotherapy approaches (radical prostatectomy, cryotherapy, high-intensity focused ultrasound), and reported that the non-radiotherapy methods showed similar efficacy but worse toxicity than radiotherapy. The conclusion was that salvage brachytherapy was effective and safe with careful selection and advanced imaging, and that it remained a leading technique for tumour control, reductions in side effects, and good quality of life.

Application in breast cancer A discussion highlighted that the use of intraoperative brachytherapy (IORT) was often recommended for local relapse in breast cancer, as it allowed precise tube placement during surgery to avoid a second procedure and reduce complications. A paper was published on this approach regarding a study of 24 patients, and it demonstrated the feasibility of its use. IORT is advantageous because the surgeon removes the tumour, accurate placement of clips and tubes is ensured and hence optimal dosimetry, which is difficult to achieve with external radiotherapy. A 2013 publication from the ESTRO breast cancer working group on 200 patients who had been treated with a second conservative treatment plus brachytherapy showed a low relapse rate (5.6% at five years) and good cosmetic outcomes (85%). Hospital data on 40 patients who were followed up for over five years also showed low relapse rates. The literature contains extensive studies that support the use of brachytherapy for these patients, and external radiotherapy is also a viable option with guidelines supporting its use. The TAM score can be used to help to identify candidates for second conservative treatment, and this can aid in minimising treatment volume and respecting patient preferences.

Application in head-and-neck cancers Dr. Luca Tagliaferri discussed perspectives on head-and-neck cancer recurrence after full-course radiotherapy. Surgery is often the first choice, but a combination of surgery with adjuvant radiotherapy/chemo improves local control and disease-free survival rates, but not OS due to high toxicity. Interventional radiotherapy (brachytherapy) offers an opportunity to enhance outcomes as an exclusive or perioperative approach. Studies show promising results with the use of radiotherapy alone using pulsed-dose-rate brachytherapy and iodine-125 seed implantation. Perioperative interventional radiotherapy involves catheter placement on the tumour bed post-debulking for targeted treatment of microscopic disease, showing improved local control and survival, especially with collaboration and advanced technologies (3D printing, endoscopy).

 

3. 𝘕𝘦𝘹𝘵-𝘨𝘦𝘯𝘦𝘳𝘢𝘵𝘪𝘰𝘯 𝘳𝘢𝘥𝘪𝘰𝘵𝘩𝘦𝘳𝘢𝘱𝘺: 𝘙𝘦𝘪𝘳𝘳𝘢𝘥𝘪𝘢𝘵𝘪𝘰𝘯 & 𝘍𝘓𝘈𝘚𝘏
   𝘚𝘺𝘮𝘱𝘰𝘴𝘪𝘶𝘮
   C𝗵𝗮𝗶𝗿𝘀: Stefanie Corradini (Germany), Jonas Willmann (Switzerland)

➤ Speakers: Yolande Lievens, Véronique Vendrely, Myriam Ayadi Zahra, Elettra Ferrari, Donato Pezzulla, Anouk Sesink, Elise Konradsson, Filip Härberger

Three talks during this symposium covered topics related to reirradiation. This session highlighted the expanding and nuanced role of reirradiation in modern cancer care. From randomised data in pelvic recurrences to high-precision ion therapy and real-world peer-reviewed clinical workflows, the evolving landscape of reirradiation emphasises multidisciplinary collaboration, robust data integration, and patient-specific decision-making.

Reirradiation in locally recurrent rectal cancer: GRECCAR15 Phase III trial (Véronique Vendrely)

The GRECCAR15 trial addressed a key clinical dilemma: whether neoadjuvant reirradiation added value to systemic therapy in patients with locally recurrent rectal cancer (LRRC) who had previously been treated with radiation. In this randomised phase III study, 58 patients were assigned to either neoadjuvant FOLFIRINOX alone or with pelvic reirradiation afterwards through the use of intensity-modulated radiotherapy (30.6Gy in 17 fractions with capecitabine). Although feasibility and safety were confirmed—with no increase in grade ≥3 perioperative morbidity—the addition of reirradiation failed to improve R0 resection rates significantly (56.5% vs. 52.2%). Despite early trial closure due to low accrual, the study contributed important insights into the balancing of treatment intensification and surgical outcomes in LRRC.

Virtual multidisciplinary reirradiation boards: improving decision-making (Myriam Ayadi Zahra)

A French multicentre initiative presented a structured, virtual peer review model for complex reirradiation cases. Over 12 months, 113 cases were discussed in 47 meetings that involved 13 institutions. The meetings—centred on indications, dose prescriptions, and cumulative EQD2 dose evaluation using MIM software—resulted in major clinical changes in a substantial portion of cases: altered dose prescriptions (35%), disapproved indications (16%), and calls for re-planning due to OAR constraints (7%). This collaborative framework was particularly valuable for young radiation oncologists and contributed to the harmonisation of practice across regions.

Carbon ion reirradiation for sacral chordoma: promising results from retrospective analysis (Elettra Ferrari)

Carbon ion reirradiation (CIR) was explored in a cohort of 33 patients with recurrent sacral chordoma who had been treated previously with photon, proton, or carbon ion radiotherapy. With a median follow-up of 32 months, two- and three-year OS rates reached 91% and 87%, respectively, with modest toxicity (three cases of grade 3 events). In-field PFS after two and three years was 50% and 29% respectively. Notably, seven patients underwent a second course of CIR, with favourable disease control in most. These results support CIR as a safe and effective reirradiation option in selected patients, offering a nonsurgical salvage alternative.

 

Dr Bartek Tomasik
Department of Oncology and Radiotherapy, Faculty of Medicine
Medical University of Gdańsk
Gdańsk, Poland
Member of the ESTRO reirradiation focus group
ESTRO 2025 Social media ambassador for reirradiation
bartlomiej.tomasik@gumed.edu.pl
LinkedIn: Bartłomiej Tomasik
X: https://x.com/B_Tomasik (@B_Tomasik)

 

 

Dr Gian Marco Petrianni
Operative Research Unit of Radiation Oncology
Fondazione Policlinico Universitario Campus Bio-Medico
Rome, Italy
Member of the ESTRO reirradiation focus group
ESTRO 2025 Social media ambassador for reirradiation
g.petrianni@policlinicocampus.it
LinkedIn: Gian Marco Petrianni
X: Gian Marco Petrianni