Prognostic factors of local control and progression-free survival in AJCC stages T1 and T2 cervical cancer patients treated with adjuvant brachytherapy after chemoradiotherapy.

Purpose: We assessed prognostic factors of local control and progression-free survival (PFS) of patients treated for AJCC stages T1 and T2 cervical cancer using utero-vaginal brachytherapy after chemoradiotherapy. Material and methods: This retrospective single-institution analysis included patients who underwent brachytherapy after radiochemotherapy between 2005 and 2015 at the Institut de Cancérologie de Lorraine. Adjuvant hysterectomy was optional. A multivariate analysis of prognostic factors was carried out. Results: Of 218 patients, 81 (37.2%) were AJCC stage T1, and 137 (62.8%) were AJCC stage T2. 167 (76.6%) patients had squamous cell carcinoma, 97 (44.5%) patients had pelvic nodal disease, and 30 (13.8%) patients had para-aortic nodal disease. One hundred eighty-four patients (84.4%) underwent concomitant chemotherapy, while adjuvant surgery was performed in 91 patients (41.9%) and 42 (46.2%) patients had pathological complete response. Median follow-up was 4.2 years, and local control was reported in 87.8% (95% CI: 83.0-91.8) and 87.2% (95% CI: 82.3-91.3) of patients at 2 and 5 years, respectively. In multivariate analysis, T stage (hazard ratio [HR] = 3.65, 95% CI: 1.27-10.46, p = 0.016) was associated with local control. PFS was reported in 67.6% (95% CI: 60.9-73.4) and 57.4% (95% CI: 49.3-64.2) of patients at 2 and 5 years, respectively. In multivariate analysis, para-aortic nodal disease (HR = 2.03, 95% CI: 1.16-3.54, p = 0.012), pathological complete response (HR = 0.33, 95% CI: 0.15-0.73, p = 0.006), and intermediate-risk clinical tumor volume of > 60 cc (HR = 1.90, 95% CI: 1.22-2.98, p = 0.005) were associated with PFS. Conclusions: Lower dose brachytherapy may benefit AJCC stages T1 and T2 tumors, whereas higher doses are required for larger tumors and para-aortic nodal disease involvement, respectively. Pathological complete response should be associated with better local control and not surgery.

Radiomics Method for the Differential Diagnosis of Radionecrosis Versus Progression after Fractionated Stereotactic Body Radiotherapy for Brain Oligometastasis.

Stereotactic radiotherapy (SRT) is recommended for treatment of brain oligometastasis (BoM) in patients with controlled primary disease. Where contrast enhancement enlargement occurs during follow-up, distinguishing between radionecrosis and progression presents a critical challenge. Without pathological confirmation, decision-making may be inappropriate and delayed. Quantitative imaging features extracted from routinely performed examinations are of interest in potentially addressing this problem. We explored the added value of the radiomics method for the differential diagnosis of these two entities. Twenty patients who received SRT for BoM, from any primary location, were included (8 radionecrosis, 12 progressions, pathologically confirmed). We assessed the clinical relevance of 1,766 radiomics features, extracted using IBEX software, from the first T1-weighted postcontrast magnetic resonance imaging (MRI) after SRT showing a lesion modification. We evaluated seven feature-selection methods and 12 classification methods in terms of respective predictive performance. The classification accuracy was measured using Cohen's kappa after leave-one-out cross-validation. In this work, the best predictive power reached was a Cohen's kappa of 0.68 (overall accuracy of 85%), expressing a strong agreement between the algorithm prediction and the histological gold standard. Prediction accuracy was 75% for radionecrosis, and 91% for progression. The area under a curve reached 0.83 using a bagging algorithm trained with the chi-square score features set. These findings indicated that the radiomics method is able to discriminate radionecrosis from progression in an accurate, early and noninvasive way. This promising study is a proof of concept, preceding a larger prospective study for defining a robust model to support decision-making in BoM. In summary, distinguishing between radionecrosis and progression is challenging without pathology. We built a classification model based on imaging data and machine learning. Using this model, we were able predict progression and radionecrosis in, respectively, 91% and 75% of cases.

Effect of bladder distension on doses to organs at risk in Pulsed-Dose-Rate 3D image-guided adaptive brachytherapy for locally advanced cervical cancer.

PURPOSE: To evaluate the impact of bladder distension on doses to organs at risk in patients treated with 3D image-guided adaptive pulsed-dose-rate (PDR) brachytherapy (BT) for locally advanced cervical cancer. METHODS AND MATERIALS: Twenty-two patients who had previously been treated by external beam radiation therapy (EBRT), underwent BT treatment planning to a pelvic MRI (or a CT scan in case of contraindication) after their bladder was filled with 100 cc of physiological saline (full bladder). This was immediately followed by a CT scan after emptying of the bladder. A fusion of these two examinations was conducted, and the dosimetry was duplicated for the study with an empty bladder. Equieffective doses of 2 Gy per fraction from EBRT and BT of bladder/rectum/sigmoid colon/small bowel were compared. RESULTS: A full bladder condition was found to be non-inferior in terms of the bladder D2cc (a difference of -0.9 Gy; 97.5% CI [-∞; 2.6]), and it resulted in a reduction in the bladder D0.1cc (p = 0.038). Bladder expansion resulted in a significant reduction of maximum doses received by the small bowel, both in terms of the D0.1cc (51.2 Gy vs. 63.4 Gy, p < 0.001) and the D2cc (48.5 Gy vs. 53.6 Gy, p < 0.001). A negative correlation was seen between the difference in the small bowel D2cc and the body mass index; (r = -0.55; p = 0.008). No differences were noted in regard to doses to the rectum and sigmoid colon. CONCLUSIONS: Bladder distension with 100 cc of physiological saline can reduce maximum doses received by the small bowel without the alteration of the doses received by the other organs at risk during a 3D image-guided adaptive PDR BT for locally advanced cervical cancer. However, the maintenance of a predefined bladder volume is difficult to achieve with PDR BT, whereas it could be easily managed before each session in case of high-dose-rate BT.