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Objectives: To evaluate the agreement among radiologists in the evaluation of rectal cancer staging and restaging (after neoadjuvant therapy) and assess whether locoregional recurrence can be predicted with this information. Materials and Methods: Pre-neoadjuvant and after-neoadjuvant therapy magnetic resonance imaging (MRI) examinations of 239 patients diagnosed with locally advanced rectal cancer were retrospectively reviewed by three radiologists. The agreement between the MRI findings (localization of tumor involvement, tumor coverage pattern, external sphincter involvement, mucin content of the mass and lymph node, changes in the peritoneum, MRI T stage, distance between tumor and MRF, submucosal sign, classification of locoregional lymph node, and EMVI) was discussed at the September 2023 meeting of the Society of Abdominal Radiology (SAR) and the interobserver and histopathological findings were examined. The patients were evaluated according to locoregional rectal cancer and lateral lymph node (LLN) staging, and re-staging was performed using MRI images after neoadjuvant treatment. The ability of the locoregional and LLN staging system to predict locoregional recurrence was evaluated. Results: Among the parameters examined, for the MRI T stage and distance between the tumor and the MRF, a moderate agreement (kappa values: 0.61–0.80) was obtained, while for all other parameters, the interobserver agreement was notably high (kappa values 0.81–1.00). LLNs during the restaging with an OR of 2.1 (95% CI = 0.33–4.87, p = 0.004) and a distance between the tumor and the MRF of less than 1 mm with an OR of 2.1 (95% CI = 1.12–3.94, p = 0.023) affected locoregional recurrence. A multivariable Cox regression test revealed that the restaging of lymph nodes among the relevant parameters had an impact on locoregional recurrence, with an OR of 1.6 (95% CI = 0.32–1.82, p = 0.047). With the LLN staging system, an increase in stage was observed in 37 patients (15.5%), and locoregional recurrence was detected in 33 of them (89.2%) (p < 0.001). Conclusions: LLN staging is not only successful in predicting locoregional recurrence among MRI parameters but is also associated with a very high level of interobserver agreement. The presence of positive LLN in the restaging phase is one of the most valuable MRI parameters for poor prognosis.

Background: The aim of this study was to investigate the efficacy of post-neoadjuvant chemotherapy (NAC) ultrasound (US), magnetic resonance imaging (MRI), and F-18fluorodeoxyglucose positron emission tomography (F-18 FDG-PET/CT) for detecting post-NAC axillary lymph node(ALN) metastasis in patients who had ALN metastasis at the time of diagnosis. Methods: This study included all breast cancer patients who received NAC for ALN metastasis; underwent axillary assessment with US, MRI, or F18FDG-PET/CT; and then were operated on in the General Surgery Clinic, Adana City Research and Training Hospital, Turkey. Patients’ data were recorded, including demographic data, clinicopathological parameters, NAC regimens, and operation types. The axillary response to chemotherapy on post-NAC US, MRI, and F-18 FDG-PET/CT was compared with the postoperative histopathological result of the ALN. Results: The study included a total of 171 female patients. The mean age of the patients was 53.28 ± 10.62 years. The post-NAC assessment revealed that the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of US for detecting ALN metastasis were 59.42%, 82.35%, 82.00%, and 60.00%, respectively, while the same measures regarding MRI for detecting ALN metastasis were 36.67%, 77.78%, 73.33%, and 42.42%, respectively. The sensitivity, specificity, PPV, and NPV of F-18FDG-PET/CT were 47.50%, 76.67%, 73.08%, and 52.27%, respectively. The evaluation of dual combinations of these three imaging techniques showed that the specificity and PPV of the combined use of US and F-18FDG-PET/CT was 100%. Conclusions: The results showed that US has the highest sensitivity and specificity for detecting ALN metastasis after NAC. Furthermore, ALND may be preferred for these patients instead of SLNB if both examinations simultaneously indicate lymph node metastasis in the post-NAC assessment with US and F-18 FDG-PET/CT. SLNB may be preferred if these two examinations simultaneously show a complete response.