Radovan Vojtíšek

Association of long-term treatment outcomes with changes in PET/MRI characteristics and the type of early treatment response during concurrent radiochemotherapy in patients with locally advanced cervical cancer

Abstract 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.

Reply to: Prediction of treatment response in patients with locally advanced cervical cancer using midtreatment PET/MRI during concurrent chemoradiotherapy. In regard to Vojtíšek et al.

Prediction of treatment response in patients with locally advanced cervical cancer using midtreatment PET/MRI during concurrent chemoradiotherapy

We aimed to find metabolic, functional or morphological characteristics of the tumor predicting failure to achieve complete metabolic remission (CMR) by the midtreatment PET/MRI (positron emission tomography/magnetic resonance imaging) in cervical cancer patients. We evaluated 66 patients treated between August 2015 and November 2019 who underwent pretreatment staging, subsequent midtreatment evaluation, and definitive restaging 3 months after completing the whole treatment, all using PET/MRI. The pretreatment parameters (pre-SUVmax, pre-SUVmean, pre-MTV, pre-MTV‑S, pre-TLG, pre-TLG‑S [SUV: standard uptake value, MTV: metabolic tumor volume, TLG: total lesion glycolysis]), and the midtreatment parameters at week 5 during chemoradiotherapy (mid-SUVmax, mid-SUVmean, mid-MTV, mid-MTV‑S, mid-TLG and mid-TLG-S) were recorded. The value of ADC (apparent diffusion coefficient) was also measured. Furthermore, we recorded absolute and relative changes in all parameters-∆ and ∆%. We divided the whole group of patients into "responders" (CMR) and "non-responders" (non-CMR), and compared them on the basis of the parameters from pre-PET/MRI and mid-PET/MRI. A statistically significant difference in the evaluated parameters between responders and non-responders was found for the following parameters: mid-MTV, mid-TLG, mid-TLG‑S, mid-MTV‑S, mid-tumor size, and ∆%SUVmax. According to the ROC (receiver operating characteristic) analysis, mid-MTV‑S showed the best albeit moderate discrimination ability for the prediction of non-CMR. Significant mutual correlations of all variables, in particular between mid-MTV‑S and mid-TLG‑S and between mid-MTV and mid-TLG, were found (all p < 0.05). Our study confirmed that when using the midtreatment PET/MRI we are able to identify metabolic parameters having the discrimination ability for the prediction of non-CMR. In particular mid-MTV‑S, mid-MTV, mid-tumor size, mid-TLG‑S, mid-TLG and ∆%SUVmax.

Treatment outcomes of MRI-guided adaptive brachytherapy in patients with locally advanced cervical cancer: institutional experiences

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. 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. 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. 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.