PURPOSE: We aimed to find predictive tumour characteristics as detected by interim positron-emission tomography/magnetic resonance imaging (PET/MRI) in cervical cancer patients. We also investigated the type of interim response. Furthermore, we compared the investigated parameters with disease-free (DFS) and overall survival (OS) outcomes. METHODS: We evaluated 108 patients treated between August 2015 and January 2023 with external-beam radiotherapy (EBRT) and image-guided adaptive brachytherapy (IGABT) who had undergone pretreatment staging, subsequent mid-treatment evaluation after completed EBRT and definitive restaging 3 months after completing the whole treatment using PET/MRI. Patients were then divided into two groups based on the RECIST and PERCIST criteria: responders (achieving complete metabolic response, CMR) and non-responders (non-CMR). These two groups were compared using selected parameters obtained at pre-PET/MRI and mid-PET/MRI. The early response to treatment as evaluated by mid-PET/MRI was categorized into three types: interim complete metabolic response, interim nodal response and interim nodal persistence. RESULTS: Mid-TLG‑S (the sum of total lesion glycolysis for the primary tumour plus pelvic and para-aortic lymph nodes) parameter showed the best discriminatory ability for predicting non-CMR. The second factor with significant discriminatory ability was mid-MTV‑S (the sum of the metabolic tumour volume of the primary tumour plus pelvic and para-aortic lymph nodes). The strongest factor, mid-TLG‑S, showed a sensitivity of 40% and a specificity of 90% at a threshold value of 70. We found a statistically significant association of DFS and OS with the following parameters: number of chemotherapy cycles, early response type and CMR vs. non-CMR. CONCLUSION: We were able to identify thresholds for selected parameters that can be used to identify patients who are more likely to have worse DFS and OS. The type of early response during concurrent chemoradiotherapy (CCRT) was also significantly associated with DFS and OS. These aspects represent an important contribution to the possible stratification of patients for subsequent individualised adjuvant treatment.

• Keywords
• Brachytherapy, Magnetic resonance imaging, Positron-emission tomography, Survival, Uterine cervical neoplasms,
• MeSH
• Brachytherapy MeSH
• Chemoradiotherapy * methods   MeSH
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Magnetic Resonance Imaging * MeSH
• Multimodal Imaging * MeSH
• Uterine Cervical Neoplasms * therapy   diagnostic imaging   pathology   mortality   MeSH
• Positron-Emission Tomography * MeSH
• Disease-Free Survival MeSH
• Radiotherapy, Image-Guided MeSH
• Aged MeSH
• Neoplasm Staging MeSH
• Treatment Outcome MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

PURPOSE: Image-guided adaptive brachytherapy (IGABT) is currently state of the art in the comprehensive treatment of patients with cervical cancer. Here, we report mature clinical data regarding IGABT of cervical cancer in a large patient sample, examining clinical outcomes, manifestations of late toxicities, and dosimetric findings. METHODS: Between May 2012 and October 2020, we performed a total of 544 uterovaginal IGABT applications in 131 consecutive patients with biopsy-proven cervical carcinoma not suitable for surgery. The median duration of follow-up was 43 months. RESULTS: The estimated 3‑, 4‑, and 5‑year LC rates were 88.3% (95% confidence interval [CI] 81.1-95.5), 86.9% (95% CI 78.5-95.3), and 85.5% (95% CI 76-95%), respectively. The 3‑, 4‑, and 5‑year OS estimates were 72.66% (95% CI 63.64-81.69%), 68.9% (95% CI 59.15-78.66%), and 63.96% (95% CI 52.94-74.97%), respectively. Patients who received ≥ 5 cycles of chemotherapy had statistically significantly better 3‑year recurrence-free survival (RFS) compared to patients who completed <5 cycles (79.07% [95% CI 60.81-97.34] vs. 58.10% [95% CI 47.22-68.98]; p = 0.0185). We recorded manifestations of genitourinary and gastrointestinal toxicity grade ≥3 in 6.9% and 5.3%, respectively. CONCLUSION: Our mature long-term data on the treatment patients with locally advanced cervical cancer show that excellent treatment outcomes can be achieved with MRI-based IGABT, as well as acceptable late morbidity.

• Keywords
• Chemoradiotherapy, Late toxicity, Local control, Overall survival, Uterovaginal brachytherapy,
• MeSH
• Brachytherapy * adverse effects   MeSH
• Radiotherapy Dosage MeSH
• Chemoradiotherapy adverse effects   MeSH
• Humans MeSH
• Magnetic Resonance Imaging MeSH
• Uterine Cervical Neoplasms * diagnostic imaging   radiotherapy   MeSH
• Radiotherapy, Image-Guided * adverse effects   MeSH
• Neoplasm Staging MeSH
• Treatment Outcome MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH